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Distribution Of Foraminifera And Radiolaria In Sediments Of The Scotia Sea Area, Antarctic Ocean

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Distribution Of Foraminifera And Radiolaria In Sediments Of The Scotia Sea Area, Antarctic Ocean

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Content This dissertation has been microfilmed exactly as received 68-7179 ECHOLS, Ronald Jam es, 1937- DISTRIBUTION OF FORA.MINIFERA AND RADIO LA RIA IN SEDIMENTS OF THE SCOTIA SEA AREA, ANTARCTIC OCEAN. University of Southern California, Ph.D., 1967 Geology University Microfilms, Inc., Ann Arbor, Michigan DISTRIBUTION OF FORAMINIFERA AND RADIOLARIA IN SEDIMENTS OF THE SCOTIA SEA AREA, ANTARCTIC OCEAN by R onald James E ch o ls A D i s s e r t a t i o n P re s e n te d to th e FACULTY OF THE GRADUATE SCHOOL UNIVERSITY OF SOUTHERN CALIFORNIA In P a r t i a l F u l f i l l m e n t o f th e R e q u ire m e n ts f o r th e Degree DOCTOR OF PHILOSOPHY (Geology) Septem ber, 19^7 UNIVERSITY O F SO U TH ERN CALIFORNIA THE GRADUATE SCHOOL UNIVERSITY PARK LOS ANGELES, CALIFORNIA 9 0 0 0 7 This dissertation, written by __________ .&oirald..James. E ch o ls...................... under the direction of his. Dissertation Com mittee, and approved by all its members, has been presented to and accepted by the Graduate School, in partial fulfillment of requirements for the degree of D O C T O R OF P H IL O S O P H Y Dean Chair CONTENTS Page ABSTRACT......................... 1 INTRODUCTION........................................ 3 % ♦ G e n e r a l ............................................. 3 A c k n o w le d g m e n ts ....................................................... 9 P r e v io u s w o r k ....................................................................................... 10 F i e l d and l a b o r a t o r y m e t h o d s ............................................... 12 F i e l d m ethods . ................................................................... 12 L a b o r a to r y m ethods ........................................ 13 F o r a m i n i f e r a l s tu d y ........................................................ 13 L iv in g f o r a m i n i f e r a l s t u d y ......................... . 14 R a d i o l a r i a n s tu d y .............................................................. 15 S ed im en t t e x t u r a l a n a l y s i s .................................... 15 DESCRIPTION OF THE ENVIRONMENT................................................... 17 B a th y m e try ................................... 17 O c e a n o g r a p h y .............................. 19 G e n e ra l a c c o u n t ........................................................................ 19 W ater m a s s e s ........................................................................ 22 C u r r e n t s .................................................................................. 23 The A n t a r c t i c C onvergence . ............................... 29 S ea i c e ........................ 29 E n v iro n m e n ta l p a ra m e te r s .......................... 32 T e m p e r a t u r e ............................................................................. 32 11 Page S a l i n i t y ................................................................................. 44 O x y g e n ........................................ 44 N u t r i e n t s a l t s ................................................................. . 45 S e d im e n ts . ........................................................................................... 46 T e x tu re . ................................................................................. 46 D iato m c o n t e n t ............................................................................ 52 CALCAREOUS AND NON-CALCAREOUS FORAMINIFERAL ASSEMBLAGES: A STUDY OF CARBONATE SOLUTION IN THE SCOTIA AND WEDDELL S E A S ........................................ 57 G e n e r a l ...................................................................................................... 57 D i s t r i b u t i o n o f c a l c a r e o u s an d n o n - c a l c a r e o u s a s s e m b la g e s ........................................................ 59 E v id e n c e o f s o l u t i o n o f c a l c a r e o u s t e s t s . . . . 73 C o rro d e d c a l c a r e o u s t e s t s .............................................. 74 L i v e - t o t a l r a t i o s .................................................................. 76 R e g io n a l d i s t r i b u t i o n o f t h e e v id e n c e f o r s o l u t i o n . . . . . . . 84 S o u th e r n and e a s t e r n S c o t i a R idge . . . . . . 84 N o rth e r n S c o t i a R id g e ........................................................ 86 Deep s e a ................................................................................. 88 D i s c u s s i o n ........................................................................................... 91 DISTRIBUTION OF PLANKTONIC FORAMINIFERA .......................... 100 G e n e r a l ...................................................................................................... 100 V a r i a t i o n s i n p l a n k t o n i c a s s e m b la g e s .......................... 101 i l l Page N o rth ern S c o t i a R i d g e ............................................. 105 E a s t - c e n t r a l S c o t i a S e a ........................................ 106 N o rth ern W ed dell S e a .................................................. 106 C lim a tic s i g n i f i c a n c e o f th e W eddell Sea r e l i c t p l a n k t o n i c a sse m b la g e s ................................... 108 DISTRIBUTION OF BENTHONIC FORAMINIFERA.................... I l l G e n e r a l .......................................................................................... I l l D i v e r s i t y ............................................................................ 112 S tan d in g c r o p ................................................................. 114 B a th y m e tric z o n a tio n ................................................................. 119 C a lc are o u s b a th y m e t r i c z o n a t i o n .................... 120 S lop e s o u th o f S o u th G e o r g i a ..................... 120 E a s te r n and s o u th e r n S c o t i a R idge .. .. . . 123 N o n -c a lc a re o u s b a th y m e tr ic z o n a tio n .................... 125 B a th y m e tric b o u n d a r i e s ................................... 125 B a th y a l and a b y s s a l a sse m b la g e s . . . . . . 134 Comparison w ith o t h e r d e p th z o n a tio n s . . . . 137 W ater m asses and b e n th o n lc f o r a m i n i f e r a l a s s e m b la g e s ........................................ l 4 l A byssal and t r e n c h b i o t o p e s ........................................ 145 N o n -c a lc a re o u s a b y s s a l b i o t o p e s .............................. .... . 146 D e s c r ip tio n o f b i o t o p e s ............................................. 146 S i g n i f ic a n c e o f e n v ir o n m e n ta lly r e s t r i c t e d s p e c i e s . . ................................... 177 Trench b io to p e ........................................................................... 182 l v Page C om parison w ith f o r a m i n i f e r a l fa u n a s from o t h e r t r e n c h e s ............................... 185 A b y s s a l c a l c a r e o u s a s s e m b la g e s . .............................. 186 Some o b s e r v a t i o n s on c a l c a r e o u s an d p o s s i b l y s i l i c e o u s a g g l u t i n a t e d f o r a m i n i f e r a ..................... 187 D i s t r i b u t i o n o f c a l c a r e o u s a g g l u t i n a t e d f o r a m i n i f e r a ........................................................................ 188 D i s t r i b u t i o n o f w h i t e , p o s s i b l y s i l i c e o u s f o r a m i n i f e r a .............................................. 191 R e l a t i o n s h i p b etw een a g g l u t i n a t e d f o r a m i n i f e r a w ith c a l c a r e o u s w a l ls an d th o s e w ith p o s s i b l y s i l i c e o u s w a l ls .................................................................. 194 DISTRIBUTION OP RADIOLARIA.............................................................. 199 G e n e r a l ........................................................................................... 199 R a d i o l a r l a n ab u n d an c e . ......................................................... 199 P a u n a l a n a l y s i s .................................................................................. 200 Spongoplegm a a n t a r c t i c u m ............................................. . 203 S p h a e r i d s ................................................................................................. 209 P e r o m e lis s a d e n t i c u l a t a and H e lo th o lu s h i s t r i c o s a ( n o t d i s t i n g u i s h e d ) ......................................................... 209 S pon g u ru s p y lo m a tic u s ......................................................... 212 D is c - s h a p e d r a d i o l a r l a n s ................................................... 219 v Page Summary o f th e r a d i o l a r i a n d i s t r i b u t i o n s . . . 219 D epth h a b i t a t s o f A n t a r c t i c r a d i o l a r i a n s . . . 222 F a c to r s i n f l u e n c i n g r a d i o l a r i a n d i s t r i b u t i o n s ..................................................................... 226 SUM M ARY AND CONCLUSIONS.............................................................. 233 SYSTEMATIC D E SC R IP T IO N S ...................................................... 242 FAUNAL REFERENCE L I S T ................................................................... 258 PLATES OF FORAMINIFERA................................................................... 279 REFERENCES.............................................................................................. . 315 APPENDIX...................................................................................................... 323 v l TABLES Table Page 1. O c c u rre n c e s o f I n t e r n a l L in in g s o f C a lc a re o u s F o r a m in i f e r a .............................................. 77 2. R e l a t i v e F re q u e n c ie s o f F o r a m in if e r a i n T o ta l A ssem b lag es ......................................... In P o c k e t 3. R e l a t i v e F re q u e n c ie s o f F o r a m in if e r a i n L iv in g F aunas ..................... I n P o c k e t 4. Summary o f T ren ch and A b y s s a l B io to p e s . . . . 173 5. O c c u rre n c e s o f R are S p e c i e s .......................................... 325 6 . Specim ens per_G ram o f S ed im en t ..................................... 327 7. R e l a t i v e F r e q u e n c ie s o f R a d i o l a r i a n s . . . . . 329 8. S edim ent P r o p e r t i e s .......................................... 331 9 . S t a t i o n L o c a tio n s and S am pling D a t a ..................... 333 v i l FIGURES Figure Page 1. In d ex M a p ........................................................................................... - 5 2. S t a t i o n L o c a tio n s .................................................................. 8 3 . G e n e r a liz e d V e r t i c a l and M e rid io n a l C i r c u l a t i o n o f A n t a r c t ic W ater M asses . . . 21 4 . S u rfa c e C u r r e n t s ......................... . . ................................ 26 5 . C u rr e n ts i n th e Warm Deep L ayer . ...................... 28 6 . C u r r e n ts i n A n ta r c tic B ottom W a t e r ........................... 31 7 . A nnual P e r io d o f Cover by S e a - i c e .......................... 34 8 . L o c a tio n o f H y drographic S t a t i o n s and V e r t i c a l P r o f i l e A-A’ .................................................. 36 9 . D i s t r i b u t i o n s o f T em p eratu re, S a l i n i t y , and Oxygen Along V e r t i c a l P r o f i l e A-A1 . . 38 10. D i s t r i b u t i o n o f T em perature a t th e L ev e l o f Maximum T em perature i n th e Warm Deep L ayer ............................................................ 4 l 11. D i s t r i b u t i o n o f T em perature a t th e -2000 M eter L e v e l .......................................................................... 43 12. P e rc e n ta g e o f Sand and G ra v el i n B ottom S edim ents ............................................................ 48 13. S i l t : C l a y R a t i o ............................. 50 14. Abundance o f Diatom s i n Bottom S ed im en ts . . . 54 15. D i s t r i b u t i o n o f A byssal C a lc a re o u s and N o n -c a lc a re o u s S u rfa c e A ssem blages and S u b s u rfa c e C a lc a re o u s A ssem blages . . . 6 l 1 6 . P e rc e n ta g e o f C a lc a re o u s Specim ens i n T o ta l B e n th o n ic A ssem blages ................................... 66 17. C a lc a re o u s B en th o n ic F o r a m in if e r a — Number p e r g r a m ................................................................. 68 viii Figure Page 18. N o n - c a lc a r e o u s B e n th o n ic F o r a m i n i f e r a - - Number p e r g ram ................................................... 70 1-9. E la n k to n ic F o r a m i n i f e r a — Number p e r gram . . . 72 20. D epth D i s t r i b u t i o n o f th e P e r c e n t a g e s o f C a lc a r e o u s S p ecim en s i n T o ta l B e n th o n ic A sse m b la g es .................................................... 79 2 1 . D epth D i s t r i b u t i o n o f th e P e r c e n ta g e s o f C a lc a r e o u s B e n th o n ic s i n L iv in g F o r a m i n i f e r a l A sse m b la g es ......................................... 8 l 2 2 . D epth D i s t r i b u t i o n o f L i v e : T o t a l R a t i o s o f C a lc a r e o u s a n d N o n -c a lc a re o u s S p e c i m e n s .................................................................................. 83 2 3 . L e v e l o f C a lc iu m C a rb o n a te S a t u r a t i o n P l o t t e d A g a i n s t D epth f o r S t a t i o n s N o rth a n d S o u th o f th e A n t a r c t i c C o n v e r g e n c e ............................................................................ 95 2 4 . S iz e and C o i l i n g R a t i o s o f G lo b i g e r i n a p a c h y d e r m a ............................................................................. 104 2 5 . D i v e r s i t y ( S im p s o n 's In d e x ) P l o t t e d A g a in s t D ep th ........................................................................ 116 2 6 . S ta n d in g C rop (S p ecim en s p e r 10 s q u a re c e n t i m e t e r s ) ................................................... 118 2 7 . D epth d i s t r i b u t i o n o f c a l c a r e o u s f o r a m i n i f e r a on th e S lo p e S o u th o f S o u th G e o rg ia . . . . 122 2 8 . C u m u lativ e Number o f N o n -c a lc a re o u s S p e c ie s Added t o an d D e le te d fro m t h e Fauna w i t h I n c r e a s i n g D e p t h .................................... 127 2 9 . G e n e r a liz e d D e p th D i s t r i b u t i o n o f I m p o r ta n t N o n - c a lc a r e o u s S p e c ie s ..................... 130 3 0 . C u m u lativ e F r e q u e n c i e s o f B a th y a l, A b y s s a l, an d N o n - d e f i n i t i v e S p ecieB P l o t t e d A g a in s t D epth ............................... 136 3 1 . C om parison o f D e p th Z o n a tio n s i n th e A n t a r c t i c ........................................................................ 140 l x Figure Page 32. S a l i n i t y - P o t e n t i a l T em p erature C u rv es S o u th o f S ou th G e o r g i a ............................................. 144 3 3 . R e la ti v e F re q u e n c ie s o f D om inant T ren ch and A b y ssa l N o n -c a lc a re o u s S p e c ie s . . . . 147 A. M a r t i n o t t l e l l a a n t a r c t i c a .......................................... 148 B. E g g e r e ll a p a rk e ra e v a r. B. . . ............................ 150 C. C rib ro s to m o id e s u m b i l i c a t u l u s s o l d a n i i . . 152 D. Reophax sp . A.......................................... • ....................... 154 E. Cyclammina p u s i l l a ........................................................ 156 F. C rib ro s to m o id e s subglobosuB .................................... 158 G. G lo m ospira c h a r o ld e s . . . . . .......................... l6 0 H. A dercotrym a g l o m e r a t u m .............................................. 162 I . T r i t a x i s in h a e r e n s ........................................................ 164 J . P o rta tro c h am m in a e l t a n l n a e ......................................... l 66_ K. Conotrocham m ina k e n n e t tl . . . ................................. 168 • L. C rib ro s to m o id e s s p h a e r l l o c u l u s ................................. 170 34. A b y ssa l B io to p e s ............................................................................ 172 35* D i s t r i b u t i o n s o f M a r t i n o t t l e l l a a n t a r c t i c a and Cyclammina p u s i l l a ............................................. 181 3 6 . O c c u rre n c e s o f Those A g g lu tin a te d F o r a m in if e r a w hich Have C a lc a re o u s Cement and Those w hich Have P o s s ib ly S i l i c e o u s Cement Com p a re d w ith the, P e rc e n ta g e o f C a lc a re o u s F o ra m in if e ra i n T o.tal A ssem blages . . . . . 190 3 7 . E g g e r e lla p a rk e ra e v a r . A and E . p a r k e r a e v a r . B: Number o f Chambers P l o t t e d A g a in s t L ength o f T e s t ............................ 197 3 8 . R a d i o l a r i a —Number o f Specim ens p e r gram . . . 202 3 9 . Spongoplegma a n ta r c tlc u m —P e r c e n t o f T o ta l R a d i o l a r i a n s ...................................... 205 4 0 . Spongoplegma a n ta r c tlc u m —Number p e r gram , . 208 4 1 . S p h a e rid R a d i o l a r i a n s — P e rc e n t o f T o ta l R a d io la r ia n s ................................... 211 4 2 . P e ro m e lls s a d e n t i c u l a t a and H e lo th o lu s h l s t r l c o s a (n o t d i s t i n g u i s h e d ) — P e r c e n t o f T o ta l R a d io l a r i a n s .............................. 214 x Figure Page 4 3 . P e r o m e lis s a d e n t i c u l a t a and H e lo th o lu s h i s t r i c o s a ( n o t d i s t i n g u i s h e d ) — Number p e r g r a m .................................................................. 216 4 4 . S p o n g u ru s p y l o m a t ic u s — P e r c e n t o f T o ta l R a d i o l a r i a n s ....................................................................... 218 4 5 . D is c - s h a p e d R a d i o l a r i a n s — P e r c e n t o f T o t a l R a d i o l a r i a n s ....................................................... 221 4 6 . R e l a t i v e F r e q u e n c ie s o f D om inant R a d io l a r i a n S p e c ie s P l o t t e d A g a in s t D epth ....................................................................... 225 x l ABSTRACT T here a r e two c o n t r a s t i n g k in d s o f f o r a m i n i f e r a l a s sem b lag es i n th e S c o t i a an d n o r t h e r n W ed d ell S e a s . One i s com posed l a r g e l y o f p l a n k t o n i c s and c a l c a r e o u s b e th o n i c s an d th e o t h e r i s l a r g e l y o f n o n - c a l c a r e o u s a g g l u t i n a t e d b e n t h o n i c s . C a lc a r e o u s a s s e m b la g e s , w h ich a r e t y p i c a l o f a r e a s n o r th o f th e A n t a r c t i c C o n v erg en ce a t d e p th s above 4000 m e te r s , a r e l a r g e l y r e s t r i c t e d to a r e a s o f th e S c o t ia Sea j u s t s o u th o f t h e A n t a r c t i c C o n v e rg e n c e . T hus, on th e n o r t h e r n S c o t ia R id g e , a t d e p th s b e tw ee n 360 m e te r s and a b o u t 3400 m e te r s , 60 to 99 p e r c e n t o f t h e b e n th o n i c s a r e c a l c a r e o u s ; b u t a t s i m i l a r d e p th s on th e s o u th e r n a n d e a s t e r n S c o t i a R id g e , o n l y 0 to 53 p e r c e n t o f th e b e n th o n ic s a r e c a l c a r e o u s . F u r th e r m o r e , d e e p - s e a a s s e m b la g e s a r e p r e d o m in a n tly n o n - c a l c a r e o u s e x c e p t f o r p r o b a b le r e l i c t c a l c a r e o u s a s s e m b la g e s i n f i v e sa m p le s from 2000 to 3780 m e te r s i n t h e n o r t h e r n W e d d e ll S e a . A s i g n i f i c a n t f a c t o r l i m i t i n g t h e d i s t r i b u t i o n o f c a l c a r e o u s f o r a m i n i f e r a i s t h e r a t e o f s o l u t i o n o f c a lc iu m c a r b o n a t e . The r a t e o f s o l u t i o n h a s b een q u a l i t a t i v e l y e s t im a te d from th e r a t i o o f l i v i n g t o t o t a l c a l c a r e o u s s p e c i mens u s i n g th e same r a t i o f o r n o n - c a l c a r e o u s sp e c im e n s a s a s t a n d a r d . V ery h ig h r a t i o s f o r c a l c a r e o u s sp e c im e n s i n d i c a t e r a p i d d e s t r u c t i o n o f em pty c a l c a r e o u s s k e l e t o n s . S o lu t i o n o f c a l c a r e o u s s k e l e t o h s , e v id e n c e d by s e v e r e l y c o r ro d e d sp e c im e n s, o c c u r s th r o u g h o u t th e a r e a , b u t th e r a t e i s a p p a r e n t l y much h i g h e r i n a r e a s o f n o n - c a lc a r e o u s a s se m b la g es th a n i n a r e a s o f c a l c a r e o u s a s s e m b la g e s . High s o l u t i o n r a t e s may p a r t i a l l y r e f l e c t t h e c h e m is tr y o f b o t tom w a te r s s in c e m e a su re m e n ts i n t h e a r e a have shown t h a t s e a w a te r i s more u n d e r s a t u r a t e d i n c a lc iu m c a r b o n a te a t a l l d e p th s s o u th o f t h e A n t a r c t i c C o n v erg en ce th a n n o r th o f i t . D epth d i s t r i b u t i o n s o f c a l c a r e o u s an d n o n - c a lc a r e o u s f o r a m i n i f e r a w ere s t u d i e d s e p a r a t e l y . A d i s t i n c t i v e u p p e r b a t h y a l (330 to 750 ni) c a l c a r e o u s f a u n a on th e n o r t h e r n S c o t i a R idge i s a s s o c i a t e d w i t h th e te m p e r a tu r e maximum s t r a tu m o f th e Warm Deep L a y e r. A t s i m i l a r d e p th s on th e s o u th e r n and e a s t e r n S c o t i a R id g e , te m p e r a t u r e s a r e 1.6°C c o l d e r and th e r a t e o f c a r b o n a t e s o l u t i o n i s v e ry h ig h ; h e r e , c a lc a r e o u s s p e c i e s a r e d o m in a n tly e u r y b a t h y a l . Seven n o n - c a lc a r e o u s f o r a m i n i f e r a l d e p th b o u n d a r ie s w ere r e c o g n i z e d , th e m ost s i g n i f i c a n t o c c u r r i n g a t 2100 to 2300 me t e r s . 1 2 F iv e d i s t i n c t i v e f o r a m i n i f e r a l b i o to p e s h a v in g c h a r a c t e r i s t i c e n v iro n m en ts p a t t e r n th e a b y s s a l f l o o r s . The E a s t S c o tia B a sin b io to p e i s c h a r a c t e r i z e d by d ia to m a c e o u s s e d i m ents and m oderate d e p th s (2490 to 3470 m ). V o lc a n ic s e d i m ents i n t h e T rench Rim b io to p e „are a l s o d ia to m a c e o u s , b u t d e p th s a r e g r e a t e r (3980 to 4650 m ). The P e r i p h e r a l Wed d e l l Sea b io to p e and t h e C e n tr a l W ed d ell Sea b io to p e a re c h a r a c t e r i z e d by n o n -d ia to m a c e o u s c l a y s and s i l t y c l a y s . The T rench b io to p e I s lo c a te d below 5500 m e te rs in th e S o u th Sandwich T ren ch . In c o n t r a s t to th e h ig h ly d ia to m a c e o u s S c o tia Sea s e d i m e n ts, t h e r e a re v e ry few d ia to m s In W ed d ell Sea s e d im e n ts . The s o u th e r n l i m i t o f d ia to m a c e o u s s e d im e n ts o c c u r s i n th e n o r th e r n W eddell Sea j u s t s o u th o f th e S c o tia R id g e . From th e S c o t i a Sea to th e W eddell S ea, c o n c u r r e n t w ith th e t r a n s i t i o n from d iato m ac eo u s to n o n -d ia to m a c e o u s s e d im e n ts , th e abundance o f r a d i o l a r i a n s f a l l s fro m more th a n 1 0 ,0 0 0 to l e s s th a n 10 specim ens p e r gram o f se d im e n t and th e c h a r a c t e r o f th e r a d i o l a r i a n a sse m b la g e s ch an g e s m a rk e d ly . The dom inant S c o tia Sea r a d i o l a r i a n s p e c i e s a re a lm o st la c k in g i n s p a rs e W eddell Sea a sse m b la g e s t h a t a r e composed o f a gro u p o f s p h e r i c a l r a d i o l a r i a n s p e c i e s . These s p h e r i c a l s p e c i e s a p p e a r to b e s u r v i v o r s i n an e c o l o g i c a l l y m ar g i n a l e n v iro n m en t. Low p rim a ry p r o d u c t i v i t y s u g g e s te d by r a r i t y o f diato m s i n W eddell Sea se d im e n ts may be a f a c t o r c a u s in g th e W eddell Sea en v iro n m en t to be m a rg in a l f o r r a d i o l a r i a n s . One new g e n u s, P o rta tro c h a m m in a , and f i v e new s p e c i e s o f F o r a m ln if e r id a a re d e s c r i b e d . The new s p e c ie s a r e : A m m o flin tin a a r g e n t e a , Conotrocham m ina k e n n e t t i , G y ro ld ln a s u b p l a n u l a t a , P o rtatro ch am m in a e l t a n i n a e , and Trochammina q u a d rlc a m e r a ta . The g enus Cystammina Newmayr i s emended and t r a n s f e r r e d from th e Trocham m inidae to th e R z e h a k in ld a e . i INTRODUCTION G e n e ra l The p u r p o s e o f t h i s s tu d y i s to d e te rm in e t h e d i s t r i b u t i o n s o f f o r a m i n i f e r a i n s e d im e n ts o f t h e S c o t i a S e a and n o r t h e r n W e d d e ll Sea and to r e l a t e them t o p r o p e r t i e s o f th e w a te r and s u b s t r a t e . D uring t h e c o u rs e o f t h e i n v e s t i g a t i o n , r e g i o n a l d i f f e r e n c e s i n r a d i o l a r i a n f a u n a s w ere n o t e d . S in c e t h e s e have s i g n i f i c a n t e n v iro n m e n ta l i m p l i c a t i o n s , t h e d i s t r i b u t i o n s o f s e l e c t e d r a d i o l a r i a n s p e c i e s o r g r o u p s o f s p e c i e s w ere a l s o s t u d i e d . T o ta l ( l i v e p l u s d e a d ) f o r a m i n i f e r a l a sse m b la g e s w ere s t u d i e d i n 89 s a m p le s , l i v i n g f o r a m i n i f e r a l p o p u l a t i o n s i n 3^ s a m p le s, and r a d i o l a r i a n s i n 67 s a m p le s . The a r e a i n v e s t i g a t e d l i e s i n th e s o u th w e s te rn A t l a n t i c Ocean B e c to r o f th e S o u th e rn Ocean an d i s b o u n d ed a p p r o x i m a t e l y by l a t i t u d e s 48°S and 67°S an d l o n g i t u d e s 21°W a n d 51°W ( F ig u r e l ) . As th e A n t a r c t i c C o n v erg en ce i s l o c a t e d a lo n g i t s n o r t h e r n b o u n d a ry , th e s tu d y a r e a i s w i t h i n t h e A n t a r c t i c zo n e o f t h e S o u th e rn Ocean (D eacon, 1 9 6 3 ) . T h is s tu d y i s b a s e d on m a t e r i a l s c o l l e c t e d b y s t a f f members o f th e U n i v e r s i t y o f S o u th e rn C a l i f o r n i a M a rin e 3 F ig u re 1 In d e x map o f th e S c o t i a S ea A rea 4 5 90*W 2000M> • if INDEX MAP FI8U R E I B io lo g y P ro g ram . S am pling was c o n d u c te d fro m t h e U .S . A n t a r c t i c R e s e a r c h S h ip , U .S .N .S . ELTANIN, on C r u i s e s J3 8 , and 9 i n 196 3 an d C r u is e 12 i n 1964. I n g e n e r a l , r o u t i n e sa m p le s w ere ta k e n a b o u t one d e g re e o f l a t i t u d e a p a r t a lo n g v a r i o u s n o r t h - s o u t h t r a v e r s e s , a lt h o u g h a more com plex s a m p lin g p a t t e r n was u s e d i n th e a r e a o f t h e S o u th S andw ich T ren c h on C r u is e 8 (F ig u r e 2 ) . T hese b a s i c s a m p lin g p a t t e r n s w ere su p p le m e n te d by t h r e e s lo p e t r a v e r s e s l o c a t e d on th e n o r t h e r n , s o u t h e r n , and e a s t e r n lim b s o f t h e S c o t i a R id g e . D e p th s b etw een 200 and 7700 m e te r s w ere sa m p le d . UBe h a s b e en made o f h y d r o g r a p h ic and c a lc iu m c a r b o n a te s a t u r a t i o n m ea su re m e n ts made from th e U .S .N .S . ELTANIN by t h e s c i e n t i c s t a f f s o f Lamont G e o lo g ic a l O b B e r v a to ry . and T exas A&M U n i v e r s i t y . S ed im en t t e x t u r a l a n a l y s e s w ere c o n d u c te d a s p a r t o f t h i s s tu d y , b u t b s e was a l s o made o f th e m a rin e g e o lo g y s t u d i e s o f th e s t a f f o f F l o r i d a S t a t e U n i v e r s i t y . E ach o f t h e s e i n s t i t u t i o n s a s s i g n s i t s own s e t o f s t a t i o n num bers to I t s c o l l e c t i o n s . S in c e r e f e r e n c e I s made to t h e s t a t i o n s o f t h e v a r i o u s i n s t i t u t i o n s , t h e s e s t a t i o n s a r e h e r e d i s t i n g u i s h e d from one a n o t h e r by p r e f i x e s : th e s t a t i o n s o f t h i s s tu d y a r e p r e f i x e d by USC, th e h y d ro g ra p h y s t a t i o n s b y LGO, t h e c a r b o n a te s a t u r a t i o n s t a t i o n s b y E, and t h e m a rin e g e o lo g y s t a t i o n s b y FSU. T h ro u g h o u t t h i s r e p o r t th e te rm b a t h y a l r e f e r s to th o s e b e n th o n ic e n v iro n m e n ts from th e e d g e s o f t h e I n s u l a r s h e l v e s to 2000 m e t e r s , and a b y s s a l t o t h o s e from 2000 me- > F ig u r e 2 S t a t i o n L o c a tio n s B a th y m e try , i n p a r t , i s a f t e r Herdman (1932) an d Holmes (G oodell-, 1 9 6 4 ). Echo so u n d in g s o f th e U .S .N .S . ELTANIN from H eezen and J o h n so n ( 1 9 6 5 ) and from t h e h o u r l y d a t a s h e e t s o f th e U .S .N .S . ELTANIN w ere a ls o u s e d . 7 8 i i BATHYMETRY IN METERS □ 7 2 8 □ 736 yftOO' SOUTH r.EORQI 673*'wE*'*u \ 7 25H 4 6 0 ■ 6 7 2 -6 8 5 / □ 6 9 4 SOUTH SANDWICH ISLANDS £ > 7.645 * Tcdfi — ■ 7 0 0 ■ 4 6 1 ■ 712 ■ 1066 70S* ■ 5 4 6 to o o 607 ■ □1031 SOUTH ORKNEYS •497 □ 1062 5 0 0 -5 0 6 —A5Z6 • GRAVITY CORE A P ETERSEN GRAB 0 TRAWL SAMPLE ■ 1016 CORE WITH MENZIES TRAWL OR HYDROGRAPHIC CAST ■ SURFACE PRESENT ■ SURFACE ABSENT SL _ aiT w « - A N T A n C T i c — — — — e / N C L t — — STATION LOCATIONS FIGURE 2 t e r s to somewhat more th a n 5000 m e te r s . These d e f i n i t i o n s a r e w ith in th e f l e x i b l e l i m i t s recommended by H edgpeth (1 9 5 7 ). A cknowledgm ents The w r i t e r e x p r e s s e s s i n c e r e g r a t i t u d e to D r. O r v i l l e L. Bandy who s u g g e s te d th e p ro b le m and whose g u id a n c e , c r i t i c i s m , and p a ti e n c e made th e s tu d y p o s s i b l e . S p e c ia l th a n k s a re a ls o d i r e c t e d to D r. D. S. G o r s lin e and D r. J . L. Mohr f o r c r i t i c a l r e a d in g o f th e m a n u s c rip t and f o r h e l p f u l s u g g e s tio n s . The w r i t e r b e n e f i t e d from d i s c u s s i o n s w ith D r. J . P. K e n n e tt, Mr. R. L. K olpack, and members o f th e M ic ro p a le o n to lo g y L a b o ra to ry o f th e A lla n Hancock Founda t i o n . D r. R ic h a rd Casey k i n d ly a s s i s t e d i n i d e n t i f y i n g r a d i o l a r i a n s p e c i e s . C o l le c t i o n o f th e Bamples was f a c i l i t a t e d by th e w h o le h e a rte d c o o p e r a tio n o f t h e s h i p ’s p e r s o n n e l and s c i e n t i f i c s t a f f o f th e U .S .N .S . ELTANIN. Sedim ent t e x t u r e s w ere a n a ly z e d by Mr. P e t e r B a rn e s , Mr. R. L. K olpack, Mr. D avid Cook, and Mr. Herman Zimmerman. Mr. R. K. S t a u f f e r d r a f t e d th e f i g u r e s and Mr. M. T. Sm ith p ro v id e d ty p in g and e d i t o r i a l a s s i s t a n c e . I l l u s t r a t i o n s o f fo ram i n i f e r a l specim ens a re by th e a u t h o r ’s w if e , Mary E. Wade E c h o ls . Type sp ecim en s from th e c o l l e c t i o n s o f th e U .S . N a tio n a l Museum w ere exam ined th ro u g h th e c o u r te s y o f Dr. R ic h a rd C l f e l l l and th e s t a f f o f th e U .S . N a tio n a l Museum. 10 O f f ic e and la b o r a to r y f a c i l i t i e s were p r o v id e d by t h e .A ll a n Hancock F o u n d atio n o f th e U n iv e r s ity o f S o u th e rn C a l i f o r n i a . T h is .stu d y was s u p p o rte d by th e O f f i c e .o f A n t a r c t i c R e se a rc h o f th e N a tio n a l S c ien c e F ou ndation (G ra n t GA-2 3 8) . P re v io u s Work F o r a m in ife r a from th e S c o tia and W eddell S eas c o l l e c t e d by th e S c o t t i s h A n t a r c t ic E x p e d itio n and th e D is c o v e ry E x p e d itio n were s tu d ie d by E a rla n d (1933, 1934, 1 9 3 6 ). H is d e s c r i p t i o n s o f sam ples, l i s t s o f s p e c ie s o c c u r r e n c e s , and q u a l i t a t i v e n o te s on abundance o f s p e c ie s c o n ta in much u s e f u l in f o r m a tio n . An e a r l i e r r e p o r t on th e f o r a m i n if e r a o f th e S c o t t i s h A n t a r c t ic E x p e d itio n was p u b l i s h e d by P e a rc ey (1 9 1 4 ). S h is k h e v is h (1964) s t u d i e d a few c o re s from th e n o r th e rn S c o tia S e a . S y s te m a tic d e s c r i p t i o n s o f f o r a m i n if e r a from o t h e r p a r t s o f th e A n t a r c t ic Ocean r e s u l t e d from th e C h a lle n g e r E x p e d itio n (B rady, 1884), th e B r i t i s h A n t a r c t i c E x p e d itio n (Chapman, 1 9 l6 a ,1 9 l6 b ) , th e T e rra Nova E x p e d itio n (H eron- A lie n and E a r la n d , 1922), th e German S o u th P o la r E x p e d itio n (W lesner, 193l)> th e A u s tr a la s ia n A n t a r c t i c E x p e d itio n (Chapman and P a r r , 1937), and th e BANZARE E x p e d itio n ( P a r r , 1 9 5 0 ). S h o r te r r e p o r t s were p u b lis h e d by W arth ln (1934) and Cushman (1 9 4 5 ). Uchio ( 1960b) p u b lis h e d th e f i r s t q u a n t i t a t i v e s tu d y o f A n t a r c t ic f o r a m in if e r a b a sed on 11 sam ples from Lutzow- V 11 Holm Bay. McKnight ( 1962) s tu d ie d th e e co lo g y o f f o r a m i n if e r a I n th e R oss S ea, and Pflum ( 1966) r e p o r t e d on f o u r p r o f i l e s d i s t r i b u t e d from th e R oss Sea to th e' B e llin g s h a u s e n S ea. B la n c -V e rn e t ( 1965) s tu d ie d th e f o r a m in if e r a i n some s h a llo w - w a te r sam ples from o f f A d e lie Land. K en n ett ( 1966, i n p r e s s ) s t u d i e d 48 sam ples from th e Ross Sea and, u s in g e v id e n c e from th e d i s t r i b u t i o n o f f o r a m i n if e r a , re c o g n iz e d a d e p th o f e f f e c t i v e c a rb o n a te s o l u t io n o f o n ly 500 m e te r s . R u s s ia n w o rk e rs (S a id o v a , 1 9 6 lj S h c h e d rin a , 1964) s tu d ie d t h e d i s t r i b u t i o n o f f o r a m in if e r a in th e P a c i f i c and I n d ia n Ocean s e c t o r s o f th e A n t a r c t ic Ocean. Bandy and E ch o ls (1964) reex am in ed p r e v io u s q u a n t i t a t i v e s t u d i e s and com p a re d th e d e p th d i s t r i b u t i o n s o f c o sm o p o litan s p e c ie s i n th e A n t a r c t i c Ocean w ith t h e i r d e p th d i s t r i b u t i o n s i n tem p e r a t e o c e a n s. The . d i s t r i b u t i o n o f p la n k to n ic f o r a m in if e r a i n b o tto m se d im e n ts on b o th s i d e s o f th e A n t a r c t ic C onvergence was s t u d i e d by B l a i r ( 1965) . L iv in g p la n k to n ic f o r a m in if e r a from th e A n t a r t i c Ocean were s tu d ie d by Chen and Be' ( 1965)* Chen ( 1966) , Be' ( in p r e s s ) , and B o lto v sk o y ( 1966a ) . Hays ( 1965) h a s p u b lis h e d th e o n ly p r e v io u s q u a n t i t a t i v e a n a l y s i s o f A n t a r c t ic r a d i o l a r i a n asse m b la g es i n b o t tom s e d im e n ts . A n t a r c t ic r a d i o l a r i a n taxonomy h a s been s t u d i e d by E h ren b erg (1 8 4 4 ), H aeckel ( 1887)* H aecker ( 1908) , P opofsky (1 9 0 8 ), R le d e l (1 9 5 8 ), and Nakaseko (1 9 5 9 ). 12 F i e l d and L a b o ra to ry Methods F i e ld Methods A t o t a l o f 76 g r a v i t y c o r e s , 12 P e te rs e n g r a b s , and 1 mud sam ple f o r t u i t o u s l y r e t a i n e d i n a tr a w l were a n a ly z e d ; su p p le m e n ta ry in f o rm a tio n on l a r g e f o r a m i n if e r a l s p e c ie s (> 0 .5 0 5 mm) was p r o v id e d by M enzies tr a w l sam p les. Most o f th e c o re sam ples were ta k e n a s se co n d a ry o b j e c t i v e s d u rin g two o t h e r k in d s o f sam pling o p e r a t io n s . In one m ethod a c o r e r was su sp en d ed from th e b r i d l e o f a M enzies t r a w l ; i n th e o t h e r method a c o r e r was suspended a t th e end o f th e l i n e d u rin g h y d ro g ra p h ic c a s t s . In b o th m ethods, th e c o r e r rem ained n e a r th e ocean f l o o r u n t i l the p rim a ry sam p lin g o b j e c t i v e was co m p lete d , and w h ile t h e r e , i t o f t e n p e n e t r a t e d b o tto m s e d im e n ts two o r more tim e s . In some c a s e s th e s u r f a c e o f th e sed im en t was pushed above the c o re l i n e r a s a d d i t i o n a l se d im e n t was tamped i n t o th e low er p a r t o f th e c o re b a r r e l . When t h i s o c c u r r e d , an e f f o r t waB made to c o l l e c t th e s u r f a c e se d im e n t i n a p l a s t i c bag a f t e r rem oval o f th e l i n e r . The u p p e r segm ents o f 12 c o re s which la c k e d s u r f a c e m a t e r i a l have been u se d f o r f o r a m i n if e r a l a n a l y s i s . In p r a c t i c e , th e s e sam ples from unknown s t r a t i - g r a p h ic I n t e r v a l s u se d i n c o n ju n c tio n w ith s u r f a c e sam ples d e m o n s tra te th e u n if o r m ity o f a b y s s a l fa u n a s th ro u g h o u t th e b a s in s i n w hich th e y o c c u r r e d and th ro u g h th e unknown tim e i n t e r v a l s I n v o lv e d . S u rfa c e and n o n - s u rf a c e sam ples a re 13 i d e n t i f i e d by d i f f e r e n t sym bols on F ig u r e 2. G r a v ity c o re sa m p le s w ere ta k e n i n a t r a v e r s e from t h e S o u th Sandw ich I s l a n d s i n t o t h e S o u th Sandw ich T rench an d a c r o s s th e s o u th e r n s lo p e o f S o u th G e o rg ia I s l a n d . In a d d i t i o n , P e te r s e n g r a b s w ere o b t a i n e d i n a t r a v e r s e a c r o s s th e s o u th e rn S o u th O rkney s l o p e . A l a y e r o f s u r f a c e m a t e r i a l a b o u t 2 cm t h i c k was r e moved from e ac h g ra b sam ple and p r e s e r v e d w ith e t h y l o r i s o p r o p y l a l c o h o l . On C r u is e 7 a l c o h o l was i n tr o d u c e d i n t o th e c o re l i n e r s above t h e c o re s u r f a c e , b u t on s u b s e q u e n t c r u i s e s , 10 p e r c e n t f o r m a lin b u f f e r e d to s a t u r a t i o n w ith h ex am eth y len em in e was u s e d a s p r e s e r v a t i v e . Rose b e n g a l s t a i n was added to th e p r e s e r v a t i v e i n c o r e s b e g in n in g w ith C ru is e 8 . L a b o r a to r y M ethods F o r a m ln i f e r a l S tu d y G r a v ity c o r e s w ere s p l i t l o n g i t u d i n a l l y o r e x tr u d e d , and th e u p p e r 5 cm from o n e - h a l f o f a c o re o r th e t o t a l u p p e r 2 cm w ere rem oved f o r f o r a m l n l f e r a l a n a l y s i s . P e t e r sen g ra b sam p les w ere th o r o u g h ly m ixed w ith a r o s e b e n g a l s o l u t i o n and a llo w e d to s ta n d f o r a t l e a s t 24 h o u r s . The c o r e s and g ra b sa m p le s w ere d r i e d and w eig h ed , and th e n w ashed th ro u g h a s i e v e w ith a 0 . 0 6 l mm m esh. P rio r to c o u n tin g , sam p les w ere d ry s i e v e d on a 0 .5 0 0 mm m esh, and a l l sp ecim en s r e t a i n e d on th e l a r g e s c r e e n w ere l d e n t l - f i e d and c o u n te d . I f d e t r i t a l p a r t i c l e s w ere a b u n d an t i n th e f r a c t i o n l e s s th a n 0 .5 0 0 mm i n d ia m e te r , f o r a m i n if e r a w ere c o n c e n tr a te d by f l o t a t i o n on p e r c h l o r e t h y l e n e u n t i l th e p ro c e d u re y i e l d e d few a d d i t i o n a l sp e c im e n s. I f foram i n i f e r a w ere a b u n d a n t, th e sam ple o r c o n c e n tr a ti o n was s p l i t w ith a m o d ifie d O tto m i c r o s p l i t t e r o f 200 to 400 b e n th o n ic specim ens w hich w ere i d e n t i f i e d and c o u n te d . The m a t e r i a l w hich d id n o t f l o a t was s p l i t to an a l i q u o t e q u a l to t h a t to w hich th e c o n c e n tr a ti o n was s p l i t and th e n s ie v e d on a 0 .1 2 5 mm m esh. A l l f o r a m i n if e r a r e t a i n e d on th e 0 .1 2 5 mm mesh w ere c o u n te d and i d e n t i f i e d , a p ro c e d u re w hich r e c o v e r e d m ost s p e c ie s w hich s y s t e m a t i c a l l y r e s i s t c o n c e n tr a ti o n by f l o t a t i o n . The a l i q u o t o f th e r e s i d u e p a s s in g th ro u g h th e 0 .1 2 5 mm mesh to be c o u n te d depended upon i t s am ount, b u t u s u a l l y was a b o u t o n e - e ig h th o r o n e - f o u r t h o f t h a t u se d i n th e t o t a l c o u n t. L iv in g F o r a m ln if e r a l S tudy The sam ples w ere s t a i n e d w ith r o s e b e n g a l to d i s t i n g u is h f o r a m i n i f e r a l sp ecim en s c o n ta in in g p ro to p la s m from empty t e s t s (W alton, 1 9 5 2 ). C ounts w ere made o f a b o u t 200 s t a i n e d specim ens when p o s s i b l e , b u t i n m ost sam ples th e t o t a l l i v i n g p o p u la tio n was much l e s s . S ta in e d and d r i e d p ro to p la s m form s d a rk r e d k e r n e l s to r e l a t i v e l y t h i c k l a y e r s a g a i n s t one o r more o f th e i n t e r i o r s i d e s o f th e cham b e r s . The s t a i n e d m a t e r i a l may be found i n m ost cham bers 15 o f a specim en, o r th e g r e a t e r q u a n ti t y may be c o n c e n tr a te d i n a few o f th e l a r g e r cham bers. Most a g g l u t i n a t e d specim ens were dampened i n d i v i d u a l l y o r p la c e d i n a s m a ll drop o f w a te r on th e c o u n tin g t r a y . T h is makes th e t e s t more t r a n s p a r e n t , c a u se s s l i g h t e x p an s io n o f th e d r ie d p ro to p la s m , and b r i g h te n s th e s t a i n . I t was o f t e n n e c e s s a r y to b re a k a g g lu t i n a t e d t e s t s to v e r i f y th e n a tu r e o f th e c o n te n ts . The m ethod d e s c r ib e d was a p p lie d o n ly a f t e r much e x p e r i e n c e to 3^ sam ples o r p a r t s o f sam ples w hich had n o t been p r e v i o u s ly tam pered w ith th o ro u g h p ic k in g . R a d io l a r i a n Study R a d io la r ia n a sse m b la g es were a n a ly z e d a f t e r c o m p le tio n o f th e f o r a m i n i f e r a l s tu d y , and i f th e sam ple had been p r e v i o u s l y f l o a t e d on p e r c h l o r e t h y le n e , c o u n ts w e r e made on e q u a l a l i q u o t s o f c o n c e n tr a te and r e s i d u e . I f r a d i o l a r i a w ere a b u n d a n t, a r e p r e s e n t a t i v e s p l i t o f from 500 to 1000 specim ens was o b ta in e d w ith a m o d ifie d O tto m i c r o s p l i t t e r . The sam ples were sp re a d e v e n ly on a b la c k c o u n tin g t r a y w ith a g r i d , and s p e c ie s f r e q u e n c ie s were d e te rm in e d w ith th e a id o f a p o i n t c o u n te r . Sedim ent T e x tu r a l A n a ly sis The c o a rs e f r a c t i o n (>62 m icro n s) was s c re e n e d w ith 3 - ln c h d ia m e te r n e s tin g T y le r s i e v e s , and th e f i n e f r a c t i o n 16 was a n a ly z e d by th e p i p e t t e t e c h n iq u e . I n c o re s * th e s e g m ent d i r e c t l y b e lo w t h a t s e l e c t e d f o r f a u n a l a n a l y s i s was u t i l i z e d f o r t e x t u r a l a n a l y s i s * e i t h e r 2 to 5 cm o r 5 to 10 cm. I f a c o re was u n u s u a l l y s h o rt* o r I f th e u p p e r segm ent v a r i e d c o n s p ic u o u s ly I n t e x t u r e from th e lo w e r, th e same seg m en t was u s e d f o r b o th f a u n a l and t e x t u r a l a n a l y s e s a n d t h e c o a r s e f r a c t i o n was c a r e f u l l y s ie v e d w ith m anual a g i t a t i o n to m in im iz e damage to f o r a m i n i f e r a l t e s t s . DESCRIPTION OP THE ENVIRONMENT B a th y m e try The S c o t i a Sea i s ho unded on t h e n o r t h , e a s t , and s o u th h y t h e S c o t i a R id g e , an e lo n g a te lo o p o f i s l a n d s and s u b m a rin e r i d g e s J o i n i n g T i e r r a d e l Fuego i n t h e n o r t h to th e A n t a r c t i c P e n i n s u l a i n th e s o u th ( F ig u r e l ) . The W edd ell Sea l i e s s o u th o f th e S c o t i a R idge and e a s t o f t h e A n t a r c t i c P e n i n s u l a ; i n th e s o u th i t c u t s d e e p ly i n t o th e A n t a r c t i c C o n tin e n t. M ost o f t h e f l o o r o f t h e S c o t i a Sea i s ru g g e d (F ig u r e 2 ) , e s p e c i a l l y . th e s o u t h e a s t e r n p a r t w here r i d g e s t r e n d i n g i n a s u b m e r id io n a l d i r e c t i o n r i s e 1500 to 3000 m e te r s o v e r a d j a c e n t a r e a s o f l e v e l b o tto m (H eezen and T h a rp , 1958; A v ilo v and G e rs h a n o v ic h , 1 9 6 6 ) . T h ere i s a s m a ll b a s i n w ith a f l a t f l o o r d e e p e r th a n 5000 m e te r s J u s t n o r t h o f th e S o u th O rkney I s l a n d s (M a th e r, 1 9 6 6) . By c o n t r a s t , t h e f l o o r o f th e c e n t r a l a r e a o f th e Wed d e l l Sea i s a sm ooth a b y s s a l p l a i n , l y i n g below 4000 m e t e r s . On t h e w e s t an d n o r th w e s t i t r i s e s g e n t l y to w a rd la n d w ith o n ly I s o l a t e d r e l i e f f e a t u r e s . E a s t o f 39°W and n o r t h o f 62°30> S , h o w e v er, a s e r i e s o f e a s t - w e s t r i d g e s p a r a l l e l th e s o u th e r n lim b o f t h e S c o t i a R id g e and l o c a l l y r i s e w e ll o v e r IT 18 2000 m e te rs above th e a d j a c e n t 's e a f l o o r ( F ig u r e 2 ) . t The c o n t i n u i t y o f th e S c o t i a R idge I s b ro k e n by f i v e g a p s w hich d i v id e th e r i d g e I n t o d i s t i n c t se g m en ts e a c h w ith i t s own to p o g r a p h ic p e c u l i a r i t i e s . Two o f th e s e g a p s , e a c h .m o re th a n 250 km w ide a t t h e 2000 m e te r i s o b a t h and w ith s a d d le s more th a n 3000 m e te rs d e e p , o c c u r i n th e n o r t h e rn lim b o f th e S c o t i a R idge on e i t h e r s id e o f S o u th G eo r g i a . Of th e t h r e e g a p s 'i n th e s o u th e r n lim b o f th e S c o t ia R id g e , th e c e n t r a l one e a s t o f th e S o u th O rkney I s l a n d s a lo n g 39° to 40°W i s th e w id e s t and d e e p e s t . S o u th G e o rg ia I s l a n d and th e S o u th O rkney I s l a n d s crown seg m en ts o f t h e S c o t i a R idge w hich a r e to p p e d by b ro a d i n s u l a r s h e lv e s c o n s i d e r a b ly d e e p e r th a n th e w o rld a v e ra g e f o r s i m i l a r p h y s io g r a p h ic f e a t u r e s . A p r o f i l e a c r o s s th e s h e l f and s lo p e s o u th o f S o u th G e o rg ia I s l a n d a lo n g 38°W, and a n o th e r one a c r o s s th e s h e l f and s lo p e s o u th o f th e S o uth O rkney I s l a n d s a lo n g 4 5 °2 0 'w w ere sam p l e d f o r f o r a m i n i f e r a . The S o u th G e o rg ia B h e lf i s a b o u t 60 km w ide and 200 m e te r s deep a lo n g th e p r o f i l e j th e s lo p e a p p e a r s to be b ro k e n i n t o ru g g e d h i l l s . The s h e l f s o u th o f th e S outh O rkney I s l a n d s I s a b o u t 160 km w ide a lo n g th e p r o f i l e . The i n n e r p a r t o f t h i s s h e l f l i e s b e tw een 220 and 240 m e te r s , b u t t h e o u t e r p a r t d e e p e n s to a s h e l f b r e a k a t a b o u t 460 m e te r s . The s lo p e s o u th o f th e S o u th O rkney I s l a n d s i s r e l a t i v e l y s t e e p , a b o u t 7 ° . 19 T here a r e no I s l a n d s on th e s o u th e rn S c o tia R idge b e tw een 39°W and 31°W. I t s u p p e r s u r f a c e a p p e a rs to c o n s i s t o f r i d g e s and tro u g h s w ith e a s t - w e s t l i n e a t i o n and r e l i e f o f up to 2500 m e te r s . The e a s t e r n segm ent o f th e S c o tia R idge i s th e S outh Sandw ich I s l a n d A rc . H ere, e le v e n v o lc a n ic i s l a n d s r i s e s t e e p l y from a g e n e r a l c r e s t l e v e l s l i g h t l y d e e p e r th a n 1000 m e te r s . A c co rd in g to Heezen and Johnson ( 1965K th e i s l a n d s a r e l o c a t e d j u s t w e st o f th e e a s t e r n edge o f a t i l t e d f a u l t b lo c k . The i s l a n d a r c i s p a r a l l e l e d on i t s convex s id e by th e S outh Sandwich T ren c h , d e s c r ib e d i n d e t a i l by Heezen and Johnson ( 1 9 6 5) . T h is a r c u a t e d e p re s s io n was t r a c e d o v e r a d i s t a n c e o f 1100 km b e g in n in g w e st o f South G eorg ia and e n d in g a t 6 l° S and 21°W w here i t m erges w ith th e g e n e r a l to p o g ra p h y . M eteor Deep (8264 m ), th e g r e a t e s t known d e p th i n t h e S o u th A t l a n t i c Ocean i s found i n th e n o r t h e a s t e r n p a r t o f th e t r e n c h . W alls o f th e tr e n c h a r e s te e p (1 :5 to 1 :1 5 ) below th e 2000 fath om (3660 m) i s o b a t h . L o cal tr e n c h a b y s s a l p l a i n s have a maximum w id th o f 4 m ile s (7 .4 km). O ceanography G e n e ra l A ccount G. E. R. Deacon (1933, 1937> 19^3) h a s made th e moBt co m p reh en siv e s tu d y o f th e o cean o g rap h y o f th e stu d y a r e a , Figure 3 G e n e ra liz e d V e r t i c a l and M e rid io n a l C i r c u l a t i o n o f A n t a r c t i c W ater M asses (M o d ified from D eacon, 19&3) 20 LATITUDE SOUTH 40° 50° 60* 70° ANTARCTIC ANTARCTIC CONVERGENCE DIVERGENCE ANTARCTIC SURFACE WATER WARM DEEP LAYER ANTARCTIC I NTE RMEDIAT WATER j fz 1000- 2000- ANTARCTIC < 3 0 0 0 - BOTTOM WATER 4 0 0 0 - CIRCULATION IN A VERTICAL SECTION FROM 4 0 ° S to 7 0 ° S FIGURE 3 22 and much o f t h e f o llo w in g d i s c u s s i o n i s b a s e d on h i s w ork. W ater M asses T h ere a r e t h r e e s t r a t i f i e d w a te r m asses s o u th o f th e A n t a r c t i c C onvergences A n t a r c t i c S u r fa c e W ater, th e Warm Deep L a y e r, and A n t a r c t i c B ottom W a te r. These w a te r m asses and t h e i r g e n e r a l i z e d v e r t i c a l and m e r id io n a l c i r c u l a t i o n a r e shown i n F ig u r e 3 . A n t a r c t i c S u rf a c e W ater i s a c o ld and d i l u t e s u p e r f i c i a l s t r a tu m bounded below by a d i s c o n t i n u i t y l a y e r i n w hich te m p e r a tu r e and s a l i n i t y i n c r e a s e w ith d e p th . I t i s hom ogeneous to a d e p th o f 150 to 250 m e te rs d u rin g th e w i n t e r w ith te m p e r a tu r e s n e a r f r e e z i n g i n th e s o u th and 1° to 2°C w arm er i n th e n o r t h . S a l i n i t i e s , h i g h e s t i n th e W edd ell S e a , a r e u s u a l l y l e s s th a n 3 4 .5 ° /o o . D u rin g t h e summer a s u r f a c e l a y e r i s warmed and d i l u t e d , w h ile th e d e e p e r l e v e l s r e t a i n t h e i r w i n t e r p r o p e r t i e s . The Warm Deep L a y e r, o c c u p y in g an i n t e r m e d i a t e s tr a tu m , i s i d e n t i f i e d by a te m p e r a tu re maximum in i t s u p p e r l e v e l s and a s a l i n i t y maximum i n i t s d e e p e r l e v e l s . I t owes i t s h ig h te m p e r a tu r e s and s a l i n i t y to c o n t r i b u t i o n s o f deep w a te r d e r iv e d from lo w e r l a t i t u d e s , p r i m a r i l y i n th e A t l a n t i c . Im m e d ia te ly s o u th o f th e A n t a r c t i c C onvergence i t s maximum te m p e r a tu re i s g r e a t e r th a n 2°C and i t s maximum s a l i n i t y a p p ro a c h e s 3 4 .8 ° /o o i n some a r e a s . In th e W eddell Sea i t i s c o o le d to l i t t l e more th a n 0 .5 °C and d i l u t e d to 23 3 4 .7 ° / oo by m ixing w ith s u r f a c e and b o tto m w a te r . A n t a r c t i c Bottom W ater i s 1° to 2°C c o l d e r , b u t o n ly s l i g h t l y l e s s s a l i n e th a n th e Warm Deep L a y e r. I t i s form ed p r i m a r i l y i n th e s o u th w e s te rn W eddell Sea w here s e p a r a t io n o f se a i c e i n c r e a s e s s u r f a c e S a l i n i t i e s to more th an 3 4 .6 0 ° / oo d u rin g th e w i n t e r . These s a l i n e s u r f a c e w a te r s o f f r e e z i n g te m p e r a tu re mix w ith th e d e p le te d Warm Deep L a y e r. The r e s u l t i n g m ix tu r e s , h a v in g h ig h d e n s i t i e s , s in k to th e b o tto m (F o fo n o f f, 1 9 5 6 ). From th e W eddell Sea, A n t a r c t ic B ottom W ater s p r e a d s e a s tw a rd a ro u n d th e A n t a r c t ic C o n tin e n t and n o rth w a rd i n t o th e a d j a c e n t A t l a n t i c , I n d ia n , and P a c i f i c Ocean b a s i n s i n c r e a s i n g i n te m p e r a tu re i n th e d i r e c t i o n o f movement. C u rre n ts In th e A t l a n t i c s e c t o r o f th e A n t a r c t i c O cean, a l l th r e e w a te r m asses move i n two b a s i c c i r c u l a t i o n p a t t e r n s . One o f th e s e i s th e e a s t - s e t t i n g C irc u m p o la r C u r re n t w hich e n t e r s th e S c o t ia Sea from th e P a c i f i c B e c to r th ro u g h Drake P a s s a g e , The o t h e r i s th e c lo c k w is e W eddell Sea g y r a l w hich t r a n s p o r t s w estw ard n e a r A n t a r c t i c a , n o rth w a rd p a r a l l e l to th e A n t a r c t i c P e n in s u la i n th e w e s te rn W eddell Sea, and e a stw a rd p a r a l l e l to th e flo w o f th e C irc u m p o la r C ur r e n t i n th e n o r th e r n W eddell S ea. Thus w a te r i n th e S c o tia Sea a r r i v e s from two d i r e c t i o n s , th e W eddell Sea i n th e so u th and th e P a c i f i c Ocean i n th e w e s t. E ach w a te r mass 2 4 i n th e W eddell Sea g y r a l i s c o l d e r th a n i t s c o u n t e r p a r t from th e P a c i f i c O cean. S u rf a c e c u r r e n t s (Figure 4) a r e n o r th e a s tw a rd i n th e zone o f p r e v a i l i n g w e s t w inds n o r t h o f a low p r e s s u r e b e l t i n th e W eddell Sea a t a b o u t 6 5 °S . F a r t h e r to th e s o u th i n ' th e W ed d ell S e a , e a s t w inds p r e v a i l and s u r f a c e c u r r e n t s move w estw ard a lo n g th e c o a s t . I n th e n o r th w e s te r n S c o t i a S e a , s u r f a c e w a te r s a r e d e riv e d from t h e B e llin g s h a u s e n S e a , w h e re a s i n th e s o u t h e a s t e r n S c o t i a Sea th e y a r e d e r i v e d from th e W ed d ell S ea. Deacon (1937) i d e n t i f i e d th e n o r t h e rn b o u n d a ry o f th e W edd ell Sea c u r r e n t by a 1° to 2 .5 °C n o rth w a rd i n c r e a s e i n s u r f a c e te m p e r a tu re o v e r a d e g re e o f l a t i t u d e . He b e l i e v e s t h a t some W eddell Sea s u r f a c e w a te r s i n k s and flo w s n o rth w a rd b e n e a th B e llin g s h a u s e n S ea s u r f a c e w a te r a t th e c o n flu e n c e o f th e two. C i r c u l a t i o n i n th e Warm Deep L ayer i s i n f l u e n c e d by th e c o n f i g u r a t i o n o f t h e S c o tia R id g e. In th e s o u th e r n h e m isp h e re c u r r e n t s a r e d e f l e c t e d to t h e l e f t upon a p p r o a c h in g r i d g e s and to th e r i g h t a f t e r p a s s in g them (S v e r d ru p , 1 9 4 1 ). T hus, e a s t - s e t t i n g c u r r e n t s in th e Warm Deep L a y e r p e n e t r a t e deep w i t h in th e S c o tia Sea, t u r n n o r t h a n d n o r t h w e st to c r o s s t h e n o r t h e r n S c o t ia R id g e, and f i n a l l y t u r n to w a rd th e e a s t o r s o u t h e a s t beyond th e South Sandw ich I s la n d s ( F ig u r e 5 ) . The Warm Deep L ayer i s from th e P a c i f i c Ocean s o u th o f S o u th G e o rg ia , and from th e W eddell S ea on Figure 4 S u rfa c e C u rre n ts (M o d ifie d from H.O. P u b l. No. 705) 25 26 90°W / / 80® 70® 60® I (H.O. Pub. No. 705) 50® • GENERAL SURFACE CIRCULATION IN KNOTS FIGURE 4 Figure 5 C u r r e n t s i n th e Warm Deep L ay e r (M o d ifie d from S v e rd ru p , 19^1> an d K le p ik o v , i 9 6 0 ) 27 28 -*■ PACIFIC WATER f> WEDDELL SEA WATER (Adapted from Sverdrup, 1941 and Klepikov, I9 6 0 ) CURRENTS OF THE WARM DEEP LAYER » _______________________________________________________________FIGURE5 29 th e s lo p e s o f th e S outh Orkney I s l a n d s and th e S o u th Sand w ich I s l a n d s . A n t a r c t i c B ottom W ater from th e 3200 m e te r l e v e l i n th e W ed dell Sea c r o s s e s I n t o th e S c o tia Sea th ro u g h th e deep gap a t 39°W i n th e s o u th e rn S c o tia R id ge ( F ig u r e 6 ) . T h is w a te r i s so dense t h a t i t p r e v e n ts b o tto m w a te r from th e P a c i f i c Ocean from e n t e r i n g th e s tu d y a r e a (G ordon, 1 9 6 6) . The A n t a r c t i c C onvergence The A n t a r c t ic C onvergence (F ig u re l ) i s th e b o u n d a ry betw een A n t a r c t i c and S u b a n ta r c tic S u rfa c e W aters m arked c l e a r l y on c o n tin u o u s ly r e c o r d in g th erm o g rap h s by a 2° to 4°C n o rth w a rd i n c r e a s e i n te m p e ra tu re o v e r a d i s t a n c e o f a few k i lo m e te r s (M ack in to sh , 1946)._ I t i s d e f i n e d a lm o s t a s c l e a r l y , how ever, by r a p i d l a t e r a l te m p e r a tu re c h a n g e s a t g r e a t d e p th , i n d i c a t i n g t h a t th e c o n v erg en c e i s n o t sim p ly a s u r f a c e phenomenon (Deacon, 1 937). A n t a r c t i c S u rfa c e W ater s in k s h e re to flow n o rth w ard a t i n t e r m e d i a t e l e v e l s i n th e S u b a n t a r c ti c zone, w h ile deep w a te r from t h e n o r t h r i s e s s t e e p l y above A n t a r c t ic Bottom W ater to c o n t r i b u t e to th e Warm Deep L ay e r i n th e A n ta r c tic zone. Sea I c e The w e s te rn W eddell Sea i s u n d e r p e r e n n i a l i c e c o v e r, b u t d u rin g th e summer m onths a tongue f r e e from i c e e x te n d s Figure 6 C u r r e n ts i n A n t a r c t i c B ottom W ater (M o d ifie d from G ordon, 1966) 30 PACIFIC WATER ■ 4> WEDDELL SEA WATER (Adapted from Gordon, 1966) CURRENTS OF THE ANTARCTIC BOTTOM WATER 32 w estw ard a lo n g th e A n t a r c t i c C i r c l e to 40°W ( F ig u re 7 ) . On th e a v e ra g e , th e s o u t h e a s t e r n S c o tia Sea I s c o v e re d by I c e h a l f th e y e a r , th e maximum a v e ra g e e x t e n t o f s e a I c e r e a c h in g alm oBt to South G e o rg ia I s l a n d . E n v iro n m e n ta l P a ra m e te rs V e r t i c a l p r o f i l e s o f te m p e r a tu r e , s a l i n i t y , and oxygen from n o r th o f th e A n t a r c t i c C onvergence, s o u th a c r o s s th e S c o tia S ea, and i n t o th e W eddell Sea to 64 ° S ( F ig u r e 8 ) show th e ra n g e o f t h e s e p r o p e r t i e s i n th e s tu d y a r e a ( F ig u r e 9)* B ecause t h e n o r t h e r n p a r t o f th e t r a n s e c t (LGO 165 to LGO 182) was ta k e n i n A u g u st and S ep tem b er ( a u s t r a l w i n t e r ) , and th e s o u th e r n p a r t (LGO 266 to LGO 271) i n March ( a u s t r a l sum m er), c o n d i t i o n s i n th e s e a s o n a l l y v a r i a b le A n t a r c t i c .S u rfa c e W ater c a n n o t be com pared betw een th e two p a r t s o f t h e t r a n s e c t . T em perature R apid l a t e r a l c h a n g e s i n te m p e ra tu re a t a l l d e p th s o c c u r a t two p l a c e s a lo n g t h e l o n g i t u d i n a l p r o f i l e ( F ig u re 9 ) . The n o r th e r n (4 9 °~ 5 0 °S ) i s a t th e A n t a r c t i c C onvergence and th e s o u th e rn (a b o u t 58°S ) m arks th e s o u th e r n e x t e n t o f th e Warm Deep L ayer d e r iv e d from th e P a c i f i c O cean. On th e s lo p e so u th o f S outh G e o rg ia I s l a n d , th e te m p e r a tu re m axi mum, 2 . 15°C, o c c u r r in g a t 575 m e te r s , i s s i m i l a r to th e te m p e ra tu re maximum im m e d ia te ly s o u th o f th e A n t a r c t i c Con- Figure 7 A nnual P e r io d o f C over b y S e a - i c e (C om piled fro m H.O. P u b l. No. 705) 33 4 m um: 90°W 1"Hi 1 J I j j. m 12 Months 11 Months 10 Months 9 Months 8 Months 7 Months ' / / / \ 1-6 Months (Data from H.O. Pub. No. 705) PERIOD OF ICE COVER FIGURE 7 Figure 8 L o c a tio n o f H y d ro g ra p h ic (LGO) S t a t i o n s O ccu p ied by U .S .N .S . ELTANIN an d o f V e r t i c a l P r o f i l e A-A' 35 36 BATHYMETRY IN METERS OEOROI c tt e i t HYDROGRAPHIC (LGO) STATION LOCATIONS • I ________ / ' . FIGURE 6 Figure 9 D i s t r i b u t i o n s o f T em p eratu re, S a l i n i t y , and Oxygen alo ng V e r t i c a l P r o f i l e A-A* (D ata from J a c o b s , 1965) 37 38 ANTARCTIC CONVERGENCE 166 ^ 2 .0 AXIS OF SCOTIA RIDOC 50* 167 5 5* 177 !STA. NOS. 165 ISO 181 182 271 2 7 0 268*9 267 2 6 6 tit; oo 0.9 1000 1 .6 20 0 0 0.9' 0.0 as •0.0 4 0 0 0 8 0 0 0 TEM PER A TU RE ■342 *34.7 5 4 .7 1000 2 Q 0 0 54.7 4 0 0 0 a. 6 0 0 0 ' SALINITY o • ■ Z O 6 0 ' 4.6 1000 4 5 2000 ' 90 5 0 0 0 ' 5.0 ' 4 0 0 0 ' 9 0 0 0 OXYGEN M L/L FIGURE 9 39 C o n v e rg e n c e . I n c o n t r a s t , t h e t e m p e r a tu r e maximum a lo n g t h e s o u t h e r n S c o t i a R id g e , a t 300-500 m e t e r s , i s l e s s th a n 0 .5 ° C , s i m i l a r to t e m p e r a t u r e s "below 2000 m e te r s on t h e s l o p e s o u th o f S o u th G e o r g ia . A b y ssa l b o tto m t e m p e r a t u r e s i n c r e a s e t o th e n o r t h , b u t re m a in below 0°C t h r o u g h o u t m o st o f t h e a r e a . A map o f t h e a r e a l ' d i s t r i b u t i o n o f t e m p e r a t u r e a t th e l e v e l o f maximum t e m p e r a tu r e ( F ig u r e 10) shows t h a t t h e c o ld w a te r a s s o c i a t e d w i t h t h e s o u th e r n S c o t i a R id g e e x t e n d s a s a to n g u e n o r th w a rd a lo n g th e S o u th S a n d w ic h A rc . D eacon (19 37) p l o t t e d t h i s same p r o p e r t y i n t h e same a r e a , a s w e l l a s s a l i n i t y and p o t e n t i a l te m p e r a tu r e a t t h e l e v e l o f maximum s a l i n i t y . The maps o f th e d i s t r i b u t i o n s o f t h e s e p r o p e r t i e s show t h a t t h e Warm Deep L a y e r h a s s i m i l a r p r o p e r t i e s a lo n g t h e s o u th e r n S c o t i a R id g e and a t l e a s t t h e s o u t h e r n p a r t o f t h e S o u th Sandw ich A rc . F ig u r e 1 1 , show ing t h e d i s t r i b u t i o n o f te m p e r a tu r e a t a d e p th o f 2000 m e t e r s , i l l u s t r a t e s t h a t t h e to n g u e o f c o ld w a t e r a lo n g t h e S o u th S an d w ich A rc o c c u r s a t t h i s d e p th a s w e l l . C om pariso n o f t h e d i s t r i b u t i o n o f t e m p e r a t u r e a t th e l e v e l o f maximum t e m p e r a t u r e m easu red i n 196 3 a n d 1964 fro m t h e U .S .N .S . ELTANIN w ith t h a t m ea su re d b y D eacon i n t h e y e a r s p r e c e d i n g 1937 r e v e a l s some s i g n i f i c a n t d i f f e r e n c e s . T h i r t y y e a r s ago t h e 2°C I s o th e r m waB c o n f i n e d to t h e n o r t h e r n S c o t i a S e a , a n d a to n g u e o f w a te r c o l d e r th a n 0°C was d e t e c t e d s o u th w e s t o f th e S outh O rkney I s l a n d s . Figure 10 D i s t r i b u t i o n o f T e m p e ra tu re a t t h e L e v e l o f Maximum T e m p e ra tu re i n t h e Warm Deep L a y e r (D a ta fro m J a c o b s , 1 9 6 5 ) 40 41 w t i r •0 * t GEORGI 7 J t €> r**crtc c**cir— — i 1 r BATHYMETRY IN METERS ti'w DISTRIBUTION OF TEMPERATURE AT THE LEVEL OF MAXIMUM TEM PERA TU RE FIGURE 10 Figure .11 D i s t r i b u t i o n o f T em perature a t th e -2000 m eter L ev el (D ata from J a c o b s , 19^5) 42 2.4 BATHYMETRY IN METERS 1.2 1.0 SOUTH 0.8 iNDWICH 0.6- - 0 .4 ISLANDS \ • O.V .4000' 6 0 * V SOUTH ORKNEYS ANT ARCTIC 40* DISTRIBUTION OF TEMPERATURE AT 2 0 0 0 M LEVEL FIGURE II 44 A p p a re n tly th e Warm Deep L a y e r I n t h i s a r e a i s s u b j e c t to a p p r e c i a b le v a r i a t i o n . T hese v a r i a t i o n s a r e p r o b a b ly a s s o c i a t e d w ith th e q u a l i t y an d q u a n t i t y o f w a te r d e r iv e d a t t h i s l e v e l from th e W eddell S e a . S a l i n i t y Below A n t a r c t i c S u rfa c e W a te r, t h e t o t a l ra n g e i n s a l i n i t y i s a b o u t 0 . 1 ° / o o . A lth o u g h t h i s ra n g e o f s a l i n i t y i s u n l i k e l y to have e c o l o g i c a l s i g n i f i c a n c e , a co m p ariso n o f th e d i s t r i b u t i o n o f s a l i n i t y i n th e Warm Deep L ay e r i n t h e n o r t h e r n S c o t ia Sea w ith t h a t i n th e W ed d ell Sea i s r e v e a l i n g . S o u th o f S o uth G e o r g ia , t h e s tr a tu m w ith s a l i n i t y g r e a t e r th a n 3 4 .7 ° /o o i s o v e r a th o u s a n d m e te rs t h i c k , and th e d e p th a t w hich th e s a l i n i t y i s maximum l i e s betw een 1000 and 1500 m e te r s . In t h e W ed d ell S e a , h o w ev er, s a l i n i t i e s a s h ig h a s t h i s a r e c o n f in e d to a t h i n and d i s c o n t i n u o u s s tr a tu m no d e e p e r th a n 600 m e t e r s . The s o u th e rn e x t e n t o f t h i s lo w e r s tr a tu m o f th e Warm Deep L ay e r o f th e n o r t h e rn S c o t i a Sea te r m in a t e s a t a b o u t 58°S a s d o es th e u p p e r s t r a tu m i d e n t i f i e d b y a te m p e r a tu r e maximum. Oxygen Low est oxygen c o n c e n t r a t i o n s a r e a s s o c i a t e d w ith th e l e v e l o f maximum te m p e r a tu r e i n t h e Warm Deep L a y e r. The minimum oxygen c o n c e n tr a ti o n a lo n g th e s o u th e r n S c o t ia R idge (4 .7 2 m l / l ) i s l e s s e x tre m e th a n t h a t s o u th o f S o u th G e o rg ia (4 .0 7 b u t nowhere s o u th o f th e A n t a r c t i c C onvergence a r e v a lu e s a s low a s th o s e o f f S o u th e rn C a l i f o r n i a ( 0 .1 m l / l ) w ith w hich L u tze (1964) c o r r e l a t e d m or p h o l o g i c a l ch an g es i n some s p e c ie s o f B o l i v i n a . The p h o t o s y n t h e t i c zone i s h i g h ly o x y g e n a te d (more th a n 7 .0 m l / l ) , and i n A n t a r c t ic B ottom W ater oxygen i n c r e a s e s w ith d e p th to more th an 5.5 m l / l . N u t r i e n t S a l t s N u t r i e n t s a l t s o c c u r i n h ig h c o n c e n t r a t i o n s s o u th o f th e A n t a r c t i c C onvergence (C low es, 1938)• R e g e n e ra tio n o f p h o s p h a te o c c u r s on a m a ssiv e s c a l e betw een th e n o r t h - f l o w in g i n t e r m e d i a t e c u r r e n t and th e s o u th - f lo w in g deep c u r r e n t n o r t h o f th e A n t a r c t i c C onvergence, and a l a r g e p o r t i o n o f t h i s p h o s p h a te i s m ixed w ith th e deep c u r r e n t and r e t u r n e d to th e A n t a r c t i c zone. T h is c o n t r i b u t i o n , i n a d d i t i o n to r e g e n e r a t i o n i n th e A n t a r c t i c zone, le a d s to maximum p h o s p h a te c o n c e n t r a t i o n s i n th e Warm Deep L a y e r, A lthou gh s i l i c a t e i s r e g e n e r a t e d to a l a r g e e x te n t i n s u r f a c e w a te r s , maximum s i l i c a t e c o n c e n tr a ti o n s found i n A n t a r c t i c B ottom W ater i n d i c a t e t h a t much o f i t i s r e g e n e r a t e d a t th e s e d i m ent s u r f a c e . P h o sp h ate and n i t r a t e i n A n t a r c t i c S u rfa c e W ater n e v e r f a l l below th e w i n t e r maxima o f th e E n g lis h C h an n el; th u s th e y a re u n l i k e l y l i m i t i n g f a c t o r s to p h y to p la n k to n g ro w th . R apid p r o d u c tio n o f d ia to m s may re d u c e s i l i c a t e to v e ry low c o n c e n tr a ti o n s i n s u r f a c e w a te r s o n ly 46 i n th e n o r th e r n p a r t o f th e A n t a r c t i c z o n e. T h in -w a lle d and s p i n e l e s s d ia to m f r u s t u l e s o b s e rv e d a s s o c i a t e d w ith low s i l i c a t e c o n c e n t r a t i o n s a ro u n d S o u th G e o rg ia i n d i c a t e t h a t s i l i c a t e may be a l o c a l l i m i t i n g f a c t o r th e r e ( H a r t, 1934). S ed im en ts S e d im e n ts c o l l e c t e d from th e U .S .N .S . ELTANIN a r e b e in g s t u d i e d i n th e S e d im e n to lo g y R e s e a rc h L a b o ra to ry a t F l o r i d a S t a t e U n i v e r s i t y u n d e r t h e d i r e c t i o n o f H. G. Good- e l l , and a r e p o r t c o v e rin g C r u is e s 7 > 8 , 9> and 12, a s w e ll a s o t h e r s h a s b een made a v a i l a b l e (G o o d e ll, 1965)• T h is , i n p a r t , form s th e b a s i s o f th e summary w hich f o llo w s . Un f o r t u n a t e l y , due to s h ip d r i f t and m an e u v erin g , s e v e r a l k i lo m e te r s may s e p a r a t e d i f f e r e n t b o tto m sam ples from th e same s h ip s t a t i o n , and i n a r e a s o f c o n s id e r a b le b o tto m r e l i e f th e s e s e d im e n ts may have s i g n i f i c a n t l y d i f f e r e n t p r o p e r t i e s . F o r t h i s r e a s o n , t e x t u r a l a n a l y s i s was i n c lu d e d i n t h i s s tu d y , and th e maps o f se d im e n t t e x t u r e ( F ig u re s 12 and 1 3) a r e b a s e d on USC sa m p le s. B ecause p r e s e r v a t i v e s and b u f f e r i n g compounds w ere added to th e sam p l e s im m e d ia te ly a f t e r c o l l e c t i o n to p r e s e r v e l i v i n g s p e c i mens, c h e m ic a l a n a ly s e s w ere n o t a tte m p te d . T e x tu re The p e r c e n ta g e o f sa n d and g r a v e l i n se d im e n ts o f 90 sam ples i s shown i n F ig u r e 12, and th e r a t i o o f B l i t to Figure 12 P e rc e n ta g e o f Sand and G ra v e l in B ottom S ed im en ts 47 30* BATHYMETRY IN METERS 50* • • 60* 60* 400? □ <io 65* 10-50 >50 A H T A ffC T tC — C t f t C L £ — 90* W ♦ 0* 30* PERCENT SAND AND GRAVEL FIGURE 12 F ig u r e 13 S i I t : C l a y R a tio 49 40* 30* ao*w BATHYMETRY IN METERS ► U T H eo fK T SOUTH SANDWIC ISLANDS. 60* lUTl > R K I *000 I O W A N T A A C T iC 30* SILT/ CLAY RATIO FIGURE 13 c la y f o r 73 sa m p le s I s shown i n F ig u r e 13. T hroughout m ost o f th e a r e a , th e c o a r s e f r a c t i o n i s d o m in ated by t e r r i g e - n o u s ly d e r i v e d m in e r a l g r a i n s and r o c k fra g m e n ts . Around th e S o u th Sandw ich iB la n d s , how ever, th e c o a r s e f r a c t i o n i s a lm o s t t o t a l l y v o lc a n ic d e b r i s ; t h i s i s a ls o t r u e o f a l l sam p les i n th e S outh Sandw ich T ren ch and e a s t o f th e tr e n c h , r e f l e c t i n g se d im e n t t r a n s p o r t i n th e d i r e c t i o n o f p r e v a i l i n g w in d s and s u r f a c e c u r r e n t s . The sam ple w ith a b u n d a n t c o a r s e m a t e r i a l on th e F a lk la n d R idge i n th e n o r t h w e s te rn c o r n e r o f th e s tu d y a r e a i s G lo b ig e r in a o o z e . T e s ts o f p l a n k t o n i c f o r a m i n i f e r a a l s o a c c o u n t f o r much o f th e c o a r s e f r a c t i o n i n i s o l a t e d sam p les a c r o s s t h e n o r th e r n W eddell S e a , b u t th e s e sam p les c o n ta in much sand and g r a v e l a s w e l l . D iato m s, w hich a r e q u a n t i t a t i v e l y im p o r t a n t i n m ost a b y s s a l s e d im e n ts e x c e p t i n th e W eddell S ea, p ro b a b ly a p p e a r i n t e x t u r a l a n a ly s e s a s s i l t . The f i n e B t se d im e n t i n th e a r e a o c c u rs i n th e i n t e r i o r o f th e W eddell S e a , w ith b o th s i l t and sand i n c r e a s i n g t o w ard th e A n t a r c t i c P e n in s u la and th e S c o tia R id g e. H igh p r o p o r t i o n s o f c l a y i n th e s o u th e r n and s o u th e a s te r n S c o t ia Sea p r o b a b ly r e f l e c t t r a n s p o r t o f c la y from th e W eddell Sea a s s u g g e s te d b y G o o d e ll ( 1 9 6 5) . N o rth o f th e S outh Orkney iB lan d S s e d im e n ta tio n r a t e s a r e slow i n th e c e n t e r o f th e S c o tia Sea and i n c r e a s e b o th n o r t h and s o u th (M ather, 1 9 6 6); th u s t h e l a r g e p r o p o r t i o n o f c o a r s e m a t e r i a l i n th e c e n t e r o f th e S c o t i a Sea may be due to la c k o f d i l u t i o n by 52 f i n e r m a t e r i a l . G o o d e ll (19&5) com m ented on t h e l a r g e b r e a d t h o f th e h a l o s o f c o a r s e m a t e r i a l a ro u n d t h e S o u th O rkney I s l a n d s and S o u th G e o rg ia I s l a n d com pared w ith t h e p r e s e n t s m a ll s i z e o f t h e s e i s l a n d s . A round th e S o u th O rkney I s l a n d s th eB e c o a r s e s e d im e n ts a p p e a r to b e r e s t r i c t e d t o th e s lo p e B , much f i n e r s e d im e n ts b e in g t y p i c a l o f t h e s h e l f . V o lc a n ic s e d im e n ts n e a r t h e S o u th S andw ich I s l a n d s a r e p r e d o m in a te ly s i l t . C om parison o f th e c h a r t o f t h e p e r c e n t a g e o f sa n d and g r a v e l i n s e d im e n ts d e te rm in e d i n t h i s s tu d y ( F i g u r e 12) w i t h t h e c h a r t p u b l i s h e d by G o o d e ll ( 1 9 6 5 * F i g u r e 9) shows t h a t i n d e t a i l , th e p a t t e r n o f s e d im e n t d i s t r i b u t i o n i n th e S c o t i a Sea i s p r o b a b ly v e r y co m p lex . ThiB i s c o n s i s t e n t w ith t h e ru g g e d r e l i e f c h a r a c t e r i s t i c o f much o f th e b a s i n . As an e x tre m e e x am p le , t h e s e d im e n t o f USC 712 c o n t a i n e d 5 0 .4 p e r c e n t o f sa n d an d g r a v e l and was c o l l e c t e d a t t h e same s h i p s t a t i o n a s th e s e d im e n t o f FSU PC 9 -1 6 o f G o o d e ll w hich c o n ta in e d o n ly 1 .7 p e r c e n t o f s a n d . S i l t : c l a y r a t i o s d e te rm in e d i n t h i s s tu d y ( F ig u r e 1 3) a r e lo w e r th a n t h o s e r e p o r t e d by G o o d e ll ( 1 9 6 5 * F ig u r e 6) i n .m o s t a r e a s o f t h e S c o t i a and n o r t h e r n W ed d e ll S e a s , D iatom C o n te n t D i f f e r e n c e s b etw een th e d ia to m c o n t e n t o f se d im e n tB o f m a jo r g e o g r a p h ic a r e a s o f th e S c o t i a and n o r t h e r n W ed d e ll S e a s ( F ig u r e 14) a r e so m arked t h a t th e y a r e c l e a r l y d e - Figure 14 Abundance o f DiatomB i n B ottom S edim ents 53 80*W i r 50* S 65* • S 40* BATHYMETRY (N METERS GEOR □ 6000 COMMON SOUTH ABUNDANT SANDWIC ISLANDS QOMMO 2000 SOUTH ORKNEYS COMm O JM 22*W 5 5 * 60* TRACE AMOUNTS OR ABSENT S A N T A R C T tC — --------------— C I*C L£— — -------------------------— -------------- — — — - s o * w s o * 22*W ABUNDANCE OF DIATOMS IN BOTTOM SEDIMENTS FIGURE 14 f i n e d b y q u a l i t a t i v e m ethods. The abundance o f d ia to m s was e s t im a t e d d u r in g r o u t i n e sam ple d e s c r i p t i o n s . C ut s u r f a c e s o f d ry s e d im e n t sam p les were exam ined m i c r o s c o p i c a l l y and i n some c a s e s w a te r Bmears o f th e se d im e n t on g l a s s s l i d e s w ere p r e p a r e d and exam ined w ith a m ic ro sc o p e u s in g t r a n s m it t e d l i g h t . Four c a t e g o r i e s o f d ia to m abundance i n s e d i m ents w ere r e c o g n iz e d : d iato m o o z e , a b u n d a n t, common, and r a r e o r a b s e n t . Sam ples o f d ia to m ooze t h a t a r e composed o f a b o u t 50 p e r c e n t o f d ia to m s f e e l v e ry l i g h t and have a f e l t e d t e x t u r e (G o o d e ll, 1 9 6 5)• The se d im e n ts o f t h r e e sam p les (USC 708 , 1068, IO6 9 ) from th e s o u t h e a s te r n S c o t ia Sea and one sam ple (USC IO6 0 ) from th e s o u th e rn s lo p e o f th e S c o t i a R idge a r e o f t h i s k in d . T hree o t h e r se d im e n t sa m p le s (USC 7 0 5 , 7 2 8 , 5 9 5 ) j e s tim a te d to c o n ta in more th a n 30 p e r c e n t d ia to m s , have a ls o been c l a s s i f i e d a s d ia to m ooze a lth o u g h th e y do n o t have a f e l t e d t e x t u r e . I n se d im e n ts from a r e a s d i s t a n t from th e i s l a n d s e ls e w h e re i n t h e S c o t ia S ea and e a s t o f th e S outh Sandw ich T ren c h , d ia to m s a r e a b u n d a n t (a b o u t 10 to 30 p e r c e n t o f th e s e d im e n t) . F r u s t u l e s a r e a v e ry c o n s p ic u o u s p a r t o f th e s e s e d im e n ts , b u t th e h i g h e r p r o p o r t i o n o f d e t r l t a l m a t e r i a l i n them i s c l e a r l y i n d i c a te d b y t h e i r g r e a t e r e s tim a te d w e ig h t a s com pared to d i a tom o o z e . D iatom s a r e common (a b o u t 0 .5 to 9 p e r c e n t o f th e se d im e n t) even i n th e im m ediate v i c i n i t y o f s e d im e n t s o u r c e s , th e i s l a n d s o f th e S c o tia R id g e . I n s e d im e n ts w ith common d ia to m s , f r u s t u l e s a r e r e a d i l y v i s i b l e on d ry sedim ent s u r f a c e s and s e v e r a l th o u sa n d l a r g e r d iato m s a re u s u a l l y fo u n d i n t h e p a r t o f th e se d im e n t r e t a i n e d on a 62 m icron m esh. In c o n t r a s t t o S c o t ia Sea s e d im e n ts w hich c o n ta in a w e a lth o f d ia to m s , W eddell Sea s e d im e n ts c o n ta in v i r t u a l l y none. In t h e s e s e d im e n ts , m ost o f w hich a r e c la y s o r s i l t y c l a y s , i t i s u n u s u a l to f i n d a s i n g l e f r u s t u l e i n th e sm a ll amount o f s e d im e n t r e t a i n e d on a 6 2 m icron mesh o r i n w a te r sm ears o f t h e t o t a l s e d im e n ts . The bou n d ary betw een d l a - tom aceous s e d im e n ts and s e d im e n ts t h a t a re a lm o st d iato m f r e e o c c u rs J u s t s o u th o f th e S c o t i a R idge i n th e n o r th e r n W eddeli S e a . P re v io u s i n v e s t i g a t o r s ( P l r i e , 1913; E a r la n d , 1936; C low es, 1938) who commented on th e p a u c i t y o f d iato m s i n se d im e n ts o f t h e W eddell Sea have e i t h e r c o n s id e re d i t an enigma o r o f f e r e d e x p la n a t i o n s w hich a p p e a r in a d e q u a te to th e w r i t e r i n t h e l i g h t o f th e r a d i o l a r i a n e v id e n c e to be d is c u s s e d l a t e r . CALCAREOUS AND NON-CALCAREOUS FORAMINIFERAL ASSEMBLAGES: A STUDY OP CARBONATE SOLUTION IN THE SCOTIA AND WEDDELL SEAS G e n e ra l The p e r c e n t a g e . o f c a r b o n a te i n s e d im e n ts f a l l s o f f m a rk e d ly w ith i n c r e a s i n g s o u th l a t i t u d e i n t h e v i c i n i t y o f th e A n t a r c t i c C o n v erg en ce, and t h e r e i s v e ry l i t t l e c a rb o n a t e i n th e b e l t o f g l a c i a l m a rin e s e d im e n ts t h a t e n c i r c l e s th e A n t a r c t i c C o n tin e n t ( L i t s i t z i n , I9 6 0 ; G o o d e ll, 1 9 6 5) . T h is d e c r e a s e i n c a r b o n a te w ith i n c r e a s i n g l a t i t u d e can b e com pared to th e r e l a t i v e l y a b r u p t ch an g e from c a l c a r e o u s o o z e s to r e d c l a y low i n c a r b o n a te o c c u r r i n g w ith i n c r e a s in g d e p th i n more te m p e r a te l a t i t u d e s . S in c e t h e e a r l i e s t i n v e s t i g a t i o n s o f a b y s s a l s e d im e n ts (M urray and R e n a rd , 1884, 1 8 9 1)* i t h a s been known t h a t s e a w a t e r a t g r e a t d e p th s iB an a g g r e s s iv e s o l v e n t o f c a lc iu m c a r b o n a t e . T h ere i s l i t t l e c a r b o n a te i n t h e d e e p e s t s e d im e n ts b e c a u s e th e r a t e o f s o l u t i o n e x c e e d s th e r a t e o f a d d i t i o n b y t h e r a i n o f c a r b o n a te s k e l e t o n s o f p e l a g i c o rg a n is m s , A r e c e n t f i e l d e x p e rim e n t i n t h e t r o p i c a l P a c i f i c ( P e t e r s o n , 1 9 6 6) i n d i c a t e s t h a t th e d e e p e r l i m i t o f c a l c a r e o u s s e d im e n ts , some tim e s c a l l e d th e c a r b o n a te c o m p e n sa tio n d e p th , i s a p p r o x i 58 m a te ly d e te rm in e d by a l e v e l below w hich th e o b s e r v e d r a t e o f s o l u t i o n o f a r t i f i c a l l y su sp en d e d c a lc iu m c a r b o n a te sam p l e s I n c r e a s e s m a rk e d ly . A s h o r t d i s t a n c e n o r t h o f th e A n t a r c t i c C o n v e rg e n c e , th e c a r b o n a te c o m p e n sa tio n d e p th i s more th a n 4000 m e te r s (Hough, 1 9 5 6 ), a b o u t t h e same a s i n th e t r o p i c a l and tem p e r a t e P a c i f i c Ocean w here i t i s betw een 4000 and 4500 me t e r s ( B r a m le tte , 1 9 6 1)• N ear A n t a r c t i c a , h o w ev er, t h e c a r b o n a te c o m p e n sa tio n d e p th i s o n ly 500 m e te rs i n t h e R oss Sea ( K e n n e tt, 1 9 6 6 ) a lth o u g h e ls e w h e re a s s e m b la g e s o f c a l c a r e o u s f o r a m i n i f e r a o c c u r r i n g below 2000 m e te rs (U c h io , 1960b ; P flu m , 1 9 6 6 ) s u g g e s t a d e e p e r c o m p e n sa tio n d e p th . I n th e S c o t i a and n o r t h e r n W edd ell S e a s , t h e r e a r e a r e a s i n w h ich t h e f o r a m i n i f e r a l a sse m b la g e s a r e d o m in a n tly com posed o f p l a n k t o n i c and c a lc a r e o u s b e n th o n ic f o r a m i n i f e r a and o t h e r a r e a s i n w hich th e f o r a m i n i f e r a l a s s e m b la g e s a r e d o m ln a te ly n o n - c a l c a r e o u s a g g l u t i n a t e d f o r a m i n i f e r a . T h ro u g h o u t t h i s r e p o r t " c a lc a r e o u s f o r a m i n i f e r a " a r e d e f i n e d a s th o s e w ith s k e l e t o n s t h a t a r e d e s tr o y e d by d i l u t e h y d r o c h l o r i c a c i d . The c a l c a r e o u s b e n th o n ic f o r a m i n i f e r a i n c l u d e th e s p e c le B w ith h y a li n e w a l l s , th e r a r e s p e c i e s w ith p o r c e la n e o u s w a l l s , and a few s p e c i e s o f th e A ta x o - p h ra g m lid a e w hich h a v e a g g l u t i n a t e d w a l l s w ith a c a l c a r e o u s cem en t. The n o n - c a lc a re o u B b e n th o n ic f o r a m i n i f e r a a r e a l l s p e c i e s w ith w a l l s t h a t do n o t d i s s o l v e i n d i l u t e h y d r o c h l o r i c a c i d . 59 Some o f th e sam ples s t u d i e d w ere p r e s e r v e d in c a r e f u l l y b u f f e r e d f o rm a lin and o t h e r s i n a lc o h o l. Those p r e se rv e d i n a lc o h o l (USC 460 to USC 5^8 a s w e ll a s some o th e r s ) show th e e f f e c t s o f s o l u t i o n a s f u l l y a s th o se p r e se rv e d in fo rm a lin w hich h a s been known to c o rro d e c a l c a r eous t e s t s . I t i s im p ro b a b le t h e r e f o r e , t h a t th e tr e n d s to be d e s c r ib e d a r e due to s o l u t i o n o f c a rb o n a te by th e p r e s e r v a t i v e . D i s t r i b u t i o n o f C a lc a re o u s and N o n -c a lc a re o u s A ssem blages A lthoug h i n d e t a i l th e d i s t r i b u t i o n a l p a t t e r n s o f c a l c a re o u s and n o n - c a lc a r e o u s f o r a m i n if e r a a r e complex in th e S c o tia and W eddell S e a s , c a lc a r e o u s f o r a m i n if e r a i n g e n e r a l dom inate i n th e n o r th e r n p a r t o f th e a r e a and a t l e s s e r d e p th s w h ile n o n - c a lc a r e o u s f o r a m i n if e r a dom inate i n th e s o u th e rn p a r t o f th e a r e a and a t g r e a t e r d e p th s . The d i s t r i b u t i o n s o f c a lc a r e o u s and n o n - c a lc a r e o u s a sse m b la g es in t h i s stu d y a re b e s t u n d e r s to o d when c o n s id e r e d i n th e con t e x t o f a l a r g e r a r e a w hich i n c l u d e s Drake P a ssag e to th e w est and th e re m a in d e r o f th e W eddell Sea to th e so u th (F ig u re 1 5 ). E a r l a n d 's (l933.» 193^* 193^) q u a l i t a t i v e d e s c r i p t i o n s o f 68 sam ples from d e e p e r th a n 2000 m e te rs have 1 been u se d to o b ta in c o v e ra g e o f t h i s l a r g e r a r e a . I f E a r- lan d l i s t e d p r i m a r i l y G lo b ig e r in a and c a lc a r e o u s b e n th o n ic s p e c ie s , th e sam ple was assum ed to be c a lc a r e o u s , and i f he Figure 15 D i s t r i b u t i o n o f A b y ssa l C a lc a re o u s and N o n -c a lc a re o u s S u rfa c e A ssem blages and Known S u b s u rfa c e O c c u rre n c e s o f C a lc a re o u s A ssem blages i n th e W ed dell S e a . Sam p l e s o f t h i s I n v e s t i g a t i o n S upplem ented by 68 Sam ples D e sc rib e d Q u a l i t a t i v e l y by E a rla n d (1933# 1934, 1 9 3 6 ). S u b su rfa c e O ccu rren ces from G o o d e ll (1 964, 1 965) . 60 6l 90*W • NON-CALCAREOUS ASSEMBLAGE AT SURFACE O CALCAREOUS ASSEMBLAGE v AT SURFACE \ • NON-CALCAREOUS AT SURFACE CALCAREOUS IN CORE • CALCAREOUS IN CORE / CALCAREOUS AND NON-CALCAREOUS ASSEMBLAGES FIGURE IS l i s t e d p r i m a r i l y n o n - c a lc a r e o u s s p e c i e s , t h e sam ple w as a s sumed to b e n o n - c a l c a r e o u s . B ased upon t h e sa m p le s s t u d i e d b y th e w r i t e r , 50 p e r c e n t c a lc a r e o u s b e n th o n i c s i s c o n s i d e r e d t h e lo w e r l i m i t o f c a lc a r e o u s a s s e m b la g e s . W ith in th e a r e a o f o v e r l a p , E a r l a n d ’ s c a l c a r e o u s sa m p le s a r e n e a r c a l c a r e o u s sam p les o f t h i s s tu d y and h i s n o n - c a lc a r e o u s Bam ples a r e n e a r n o n - c a lc a r e o u s sa m p le s o f t h i s s tu d y , su p p o r t i n g th e v a l i d i t y o f u s in g h i s q u a l i t a t i v e d a t a . W hile m a r g in a l sam p les a r e d i f f i c u l t to i n t e r p r e t from q u a l i t a t i v e f a u n a l d e s c r i p t i o n s , c a l c a r e o u s f o r a m i n i f e r a a r e so r a r e s o u th o f th e A n t a r c t i c C onvergence below 2000 m e te rs t h a t an y sam ple w ith num erous c a l c a r e o u s s p e c i e s i s n o te w o rth y . T h is a n a l y s i s i s r e s t r i c t e d to d e p th s g r e a t e r th a n 2000 m e te r s b e c a u s e m a r g in a l sam p les a r e more f r e q u e n t a t l e s s e r d e p th s . F ig u r e 15 shows t h a t a sse m b la g e s n o r t h o f t h e A n ta r c t i c C onvergen ce and a s h o r t d i s t a n c e s o u th o f t h e c o n v e rg e n ce a r e c a l c a r e o u s w h ile o f th e 99 s u r f a c e sa m p le s f a r t h e r s o u th , o n ly n in e a r e c a lc a r e o u B . T hese n in e a r e w id e ly d i s t r i b u t e d i n th e W ed d ell S ea; none o c c u r i n th e S c o t i a S e a . The c a l c a r e o u s a s s e m b la g e s in th e W ed d ell Sea may be r e l i c t , a t l e a s t i n p a r t , f o r c a l c a r e o u s a s s e m b la g e s h av e b e en fou n d b elo w n o n - c a lc a r e o u s a sse m b la g e s i n two c o re sa m p le s from t h e W e d d e ll S e a . One o f th e s e i s c o re sam ple USC 516 w hich i s 45 cm lo n g and c o n t a i n s two c y c l e s o f n o n - c a lc a r e o u s and c a l c a r e o u s a s s e m b la g e s . The f i r s t c y c le i s 2 2 .5 cm lo n g and p l a n k t o n i c f o r a m i n i f e r a l t e s t s w ere f i r s t n o te d a t 8 .5 cm. The seco n d n o n - c a lc a r e o u s c y c le i s 13 cm lo n g . Core sam ple USC 516 was ta k e n w ith a M enzies Trawl w hich i s towed a lo n g th e o cean f l o o r by th e d r i f t i n g s h ip p r o v i d in g o p p o r t u n i t i e s f o r t h e c o re to sam ple th e b o tto m two o r more tim e s . In t h i s c a s e , th e c o re a p p e a rs to have sam pled th e b o tto m tw ic e , e ac h tim e p e n e t r a t i n g a t h i n s u r f a c e s e d i ment l a y e r i n w hich t h e f o r a m i n i f e r a l a sse m b la g e s a r e n o n - c a lc a r e o u s and an u n d e r ly in g l a y e r i n w hich f o r a m i n i f e r a l a sse m b la g e s a r e c a l c a r e o u s . A ssem blages i n th e 0 -5 cm (non- c a lc a r e o u s ) and 4 0 -4 5 cm ( c a l c a r e o u s ) seg m en ts were a n a ly z e d , The c o n t r a s t i n th e abundance o f c a lc a r e o u s and n o n - c a lc a r e o u s f o r a m i n i f e r a betw een th e tw o . c o re segm ents i s shown below : 0 -5 cm 4 0 -4 5 cm P la n k to n ic s (N o./gm ) 1 .1 1350 C a lc a re o u s b e n th o n ic s (N o./gm ) 0 .3 37*1 N o n -c a lc a re o u s b e n th o n ic s (N o./gm ) 1 0 .4 0 The o t h e r c o re w hich p e n e t r a t e d c a l c a r e o u s a sse m b la g e s b e low n o n - c a lc a r e o u s a sse m b la g e s i s an ELTANIN p i s t o n c o re d e s c r ib e d a t F l o r i d a S t a t e U n i v e r s i t y (G o o d e ll, 1 9 6 5) . T h is c o re (FSU PC 7 - 1 2 ) , w hich e n c o u n te re d c a lc a r e o u s s t r a t a a t a d e p th o f 42 cm, was ta k e n from a p p ro x im a te ly th e same p o s i t i o n a s th e s u r f a c e sam ple USC 517 w hich co n t a i n e d a n o n - c a lc a r e o u s a s s e m b la g e . E x a m in a tio n o f th e c o re lo g s c o m p iled a t F l o r i d a S t a t e U n i v e r s i t y r e v e a l e d o c 64 c u r r e n c e s o f c a l c a r e o u s f o r a m i n l f e r a i n two o t h e r c o r e s (FSU PC 1 2 -4 a n d FSU PC 7 “ l 4 ) from l o c a l i t i e s o t h e r th a n t h o s e sa m p le d f o r t h i s s t u d y . B e ca u se s u r f a c e m a t e r i a l was n o t a v a i l a b l e from t h e s e two p i s t o n c o re l o c a l i t i e s , th e s u r f a c e a s s e m b la g e s a r e unknow n. I n sa m p le s o f t h i s s tu d y I n w hich t h e b e n th o n lc a s se m b la g e s a r e d o m in a te d b y c a l c a r e o u s f o r a m i n l f e r a ( F ig u r e 1 6 ) , t h e r e a r e u s u a l l y m ore th a n 50 c a l c a r e o u s f o r a m i n l f e r a p e r gram o f d ry s e d im e n t ( F i g u r e 1 7 ) , t h e maximum num ber b e in g 995 sp e c im e n s p e r gram . A lth o u g h t h e r e a r e u s u a l l y l e s s th a n 50 n o n - c a l c a r e o u s sp e c im e n s p e r gram o f se d im e n t ( F i g u r e 1 8 ) , se v e n sa m p le s h a v e more th a n 100 sp ecim en s p e r gram , t h e maximum b e in g 272 sp e c im e n s p e r gram . Thus c a l'c a r e o u s f o r a m i n l f e r a o c c u r a t g e n e r a l l y g r e a t e r a b u n d a n c e s th a n n o n - c a l c a r e o u s f o r a m i n l f e r a , b u t t h e r e i s no g r e a t c o n t r a s t b e tw e e n r i c h c a l c a r e o u s f o r a m l n i f e r a l a s s e m b la g e s an d s p a r s e n o n - c a l c a r e o u s f o r a m l n i f e r a l assem b l a g e s su c h a s t h a t I n th e Ro b s Sea d e s c r i b e d by JCennett ( 1 9 6 6 ) . Seven s a m p le s fro m t h e n o r t h e r n S c o t i a R id g e , I n w hich p l a n k t o n i c f o r a m i n l f e r a a r e m ore a b u n d a n t th a n b e n th o n lc f o r a m i n l f e r a , h a v e from 63 to 4 l6 o sp e cim en s o f p l a n k t o n i c f o r a m i n l f e r a p e r gram o f s e d im e n t, and t h e f i v e c a l c a r e o u s s a m p le s fro m t h e n o r t h e r n W ed d e ll Sea h a v e fro m 147 to 1 9 ,6 0 0 p l a n k t o n i c f o r a m i n l f e r a p e r gram ( F ig u r e 1 9 ) . Most sa m p le s fro m t h e a r e a , h o w e v er, h a v e l e s s th a n two specim ens Figure 16 P e rc e n ta g e o f C a lc a re o u s Specim ens i n T o ta l (L iv e p l u s Dead) B e n th o n ic A ssem blag es 65 66 son* 2 2 * W S O * s BATHYMETRY IN METERS SOUTH GEORG SOUTH SANDWICH ISLANDS * SOUTH ORKNEYS 65* 8 - — — • / — — — — — — A H T A ftC T IC — — — — C i*C L £ — — _J i ___ J L J L 60* W 90* « * W PERCENT CALCAREOUS BENTHONICS FIGURE 16 . Figure 17 Calcareous Benthonlc Foraminlfera Number per gram of dry sediment 67 68 40* It1 * BATHYMETRY IN METERS eiacte CALCAREOUS BENTHONICS N 0./6M .; FIGURE 17 Figure 18 . Non-calcareous Benthonlc Foraminlfera Number per gram of dry sediment 69 40* BATHYMETRY IN METERS S o u t h g e o r q ij * 0 0 0 SOUTH SANDWICH ISLANDS \ SOUTH ORKNEYS ( looo< •5* M *T A *C T iC 40* NON-CALCAREOUS BENTHONICS NO./GM. FIGURE 18 Figure 19 Planktonic Foraminlfera Number per gram of dry sediment 71 72 BATHYMETRY IN M ETERS C I* C L C *o*«r tt*w PLANKTONIC FORAMINIFERA NO./GM. FIGURE 19 73 o f p l a n k t o n i c f o r a m i n l f e r a p e r gram o f s e d im e n t. A sam ple o f G l o b i g e r i n a o o z e fro m t h e F a l k l a n d R id g e , h a v in g 1 5 6 ,0 0 0 p l a n k t o n i c f o r a m i n l f e r a p e r g ram , i l l u s t r a t e s t h e c o n t r a s t b e tw e e n t h e a b u n d a n c e s o f p l a n k t o n i c f o r a m i n l f e r a o b s e r v e d s o u t h o f t h e c o n v e rg e n c e i n t h i s s tu d y and t h e a b u n d a n c e s t h a t c a n o c c u r i n s e d im e n ts n o r t h o f t h e c o n v e r g e n c e . Ac c o r d i n g to J , P . K e n n e tt ( p e r s o n a l c o m m u n ic a tio n ), who i s c u r r e n t l y s t u d y i n g p l a n k t o n i c f o r a m i n l f e r a i n t h e S o u th P a c i f i c , 1 0 0 ,0 0 0 p l a n k t o n i c f o r a m i n l f e r a p e r gram a r e n o t u n u s u a l i n sa m p le s j u s t n o r t h o f t h e A n t a r c t i c C o n v e rg e n c e . I n summary, c a l c a r e o u s f o r a m i n l f e r a d o m in a te a sse m b l a g e s s o u th o f th e A n t a r c t i c C o n v e rg e n c e on t h e n o r t h e r n S c o t i a R id g e , b u t t h e a b u n d a n c e o f c a l c a r e o u s sp e c im e n s i s much l e s s i n s a m p le s fro m t h i s a r e a th a n i n a sam p le o f G l o b i g e r i n a o o z e fro m j u s t n o r t h o f t h e c o n v e rg e n c e . F a r t h e r s o u t h , r e g a r d l e s s o f d e p th , n o n - c a l c a r e o u s f o r a m i n l f e r a d o m in a te m o st a s s e m b la g e s e x c e p t f o r a few s a m p le s • from t h e n o r t h e r n W e d d e ll S ea w h ic h may a t l e a s t i n p a r t b e r e l i c t . E v id e n c e o f S o l u t i o n o f C a lc a r e o u s T e s ts W id e s p re a d o c c u r r e n c e s o f s e v e r e l y c o r r o d e d c a l c a r e o u s t e s t s i n d i c a t e t h a t s o l u t i o n i s a f a c t o r c o n t r i b u t i n g to t h e r a r i t y o f c a l c a r e o u s f o r a m i n l f e r a i n t h e S c o t i a and W e d d e ll S e a s . A c o n s e q u e n c e o f t h e d e s t r u c t i o n o f c a l c a r - eouB s k e l e t o n s i s an I n c r e a s e i n l i v i n g c a l c a r e o u s sp e c im e n s r e l a t i v e to d e a d o n e s . B e c a u se an e n v iro n m e n t u n d e r s a t u r a t e d i n c a r b o n a t e p re s u m a b ly d o e s n o t a f f e c t n o n - c a l c a r e o u s s k e l e t o n s , t h e r a t i o o f l i v i n g to d e a d n o n - c a l c a r e o u s sp e c im e n s i s a s t a n d a r d a g a i n s t w h ic h t h e r a t i o o f l i v i n g t o d e a d c a l c a r e o u s s p e c im e n s can b e c o m p a re d . C o rro d e d C a lc a r e o u s T e s t s B e c a u se s e a w a t e r i s u n d e r s a t u r a t e d i n c a r b o n a t e b e low th e u p p e r few h u n d re d m e te r s e v e n i n t h e t r o p i c s (P e t e r s o n , 1 9 6 6 ; P y tk o w ic z , 1 9 6 5)> c o n d i t i o n s a r e su c h t h a t s o l u t i o n can o c c u r a t m o st b a t h y a l a n d a b y s s a l d e p t h s . Thus i n an u n u s u a l f i e l d e x p e r i m e n t , B e r g e r (19&7) showed t h a t p l a n k t o n i c f o r a m l n i f e r a l s k e l e t o n s e x p o s e d t o f r e e l y c i r c u l a t i n g s e a w a t e r u n d e rg o a p p r e c i a b l e s o l u t i o n o v e r a s h o r t tim e -s p a n w e l l ab o v e t h e c a r b o n a t e c o m p e n s a tio n d e p th s u g g e s t i n g t h a t p r e s e r v a t i o n o f c a l c a r e o u s t e s t s on t h e s e a f l o o r r e q u i r e s t h e p r o t e c t i o n o f a s e m i - s a t u r a t e d l a y e r o f b o tto m w a t e r . N e v e r t h e l e s s , p r e v i o u s o b s e r v a t i o n s i n d i c a t e t h a t s o l u t i o n o f c a l c a r e o u s t e s t s i s m o st w id e s p r e a d a t g r e a t d e p th s ( P h l e g e r , P a r k e r , a n d P i e r s o n , 1953) o r b e low u n u s u a l l y s h a llo w c a r b o n a t e c o m p e n s a tio n d e p th s (K en- n e t t , 1966; F r e r l c h s , 1 9 6 7 )• S o l u t i o n i s s e l e c t i v e , a f f e c t i n g s p ln o s e s k e l e t o n s m ore th a n s m o o th - w a lle d s k e l e t o n s o f p l a n k t o n i c f o r a m i n l f e r a ( B e r g e r , 1 9 6 7 ) a n d a f f e c t i n g p l a n k t o n i c s k e l e t o n s m ore th a n b e n th o n l c s k e l e t o n s ( P h l e g e r , P a r k e r , and P i e r s o n , 1953)* The e n d r e s u l t o f s e l e c t i v e 75 s o l u t i o n i s t o a l t e r t h e s p e c i e s c o m p o s itio n o f f o r a m i n i f - e r a l a s s e m b la g e s . M ost sp e c im e n s o f G l o b i g e r i n a p a ch y d e rm a , t h e d o m in an t A n t a r c t i c p l a n k t o n i c f o r a m i n i f e r , a r e d e e p ly c o rro d e d i n t h e sa m p le s o f t h i s s t u d y . B e ca u se th e t h i c k n o n - l a m e l l a r c a l c i t e c o r t e x fo rm in g th e e x t e r i o r o f t h e t e s t o f G. pachy derm s may re m a in w hole a f t e r s o l u t i o n h a s c o m p le te ly r e moved t h i n i n t e r n a l s e p t a , c o r r o s i o n may n o t be a p p a r e n t on s u p e r f i c i a l e x a m in a tio n . I n t h i s w eakened c o n d i t i o n , h o w e v e r, th e t e s t , c o r t e x p r o v i d e s a lm o s t no r e s i s t a n c e to l i g h t p r e s s u r e o f a d i s s e c t i n g n e e d l e . I n r a r e l y e n c o u n te r e d f r e s h t e s t s , th e c o r t e x i s t r a n s l u c e n t and g r e a t l y r e s i s t a n t to b r e a k a g e . . . W ith in a sa m p le , c o r r o s i o n i s i n v a r i a b l y m ore s t r o n g l y d e v e lo p e d on p l a n k t o n i c th a n on c a l c a r e o u s b e n th o n lc t e s t s . P a r t i a l s o l u t i o n was o b s e r v e d , h o w e v er, on many b e n th o n lc sp e c im e n s b e in g m ost e v i d e n t on l a r g e , t h i c k - w a l l e d , c a l c a r e o u s b e n th o n l c s p e c i e s su ch a s C i b i c i d e s g r o s s e p u n c t a t u s , p r o b a b l y b e c a u s e th e y r e t a i n t h e i r i n t e g r i t y a f t e r b e in g s u b j e c t e d t o l o n g e r p e r i o d s o f i n t e n s e c o r r o s i o n . Some c a l c a r e o u s b e n th o n l c s p e c i e s h a v e i n t e r n a l l i n i n g s w h ich re m a in a f t e r d i s s o l u t i o n o f t h e t e s t . A t o t a l o f 33 l i n i n g s , l a r g e l y o r c o m p le te ly d e v o id o f c a l c i t e , was fo u n d a t 13 s t a t i o n s . N in e te e n o f t h e s e can be c o n f i d e n t l y a s s i g n e d to E p o n id e s tu m id u lu s , a s c o m p le te g r a d a t i o n s fro m I n t e r n a l l i n i n g s to undam aged t e s t s have b een o b s e r v e d . S p e c ie s o f O l b io id e s . N o n io n e lla , a n d A s tro n o n io n a r e s u g g e s te d b y th e o t h e r 14 l i n i n g s , b u t t h e i r i d e n t i f i c a t i o n s re m a in u n c e r t a i n . I n t e r n a l l i n i n g s o f a num ber o f s p e c i e s have b een n o te d i n p a r t i a l l y d i s s o l v e d t e s t s , b u t o t h e r th a n th o s e o f E . tu m ld u lu s , th e y do n o t a p p e a r s t r o n g enough to s u r v iv e a lo n e i n s e d im e n ts . O c c u rre n c e s o f i n t e r n a l l i n i n g s a r e l i s t e d i n T ab le 1 . A specim en s l i d e o f t h e s e and o t h e r exam ples o f c o rro d e d c a l c a r e o u s t e s t s i s .on f i l e i n th e c o l l e c t i o n o f th e U n i v e r s i t y o f S o u th e rn C a l i f o r n i a . I n t e r n a l l i n i n g s , u s u a l l y a s s o c i a t e d w ith f e t i d s e d i m e n ts, have b een r e p o r t e d from m a rg in a l m arin e and n e a r s h o re e n v iro n m e n ts ( B a r t l e t t , 1964; E c h o ls and W eg w eiser, 1 9 6 7; J a r k e , 1 9 6 1) , b u t th e y a p p a r e n t l y have n o t been p r e v i o u s l y r e p o r t e d from d e e p - s e a s e d im e n ts . L iv e - T o ta l R a ti o s I n m ost o f th e sam p les i n w hich t h e sp e cim en s l i v i n g a t th e tim e o f c o l l e c t i o n w ere s t u d i e d , th e p e r c e n t a g e s o f c a l c a r e o u s f o r a m i n l f e r a i n t h e t o t a l ( l i v e p l u s d ead ) a s se m b la g e s ( F ig u r e 20) a r e much lo w e r th a n th e p e r c e n t a g e s o f c a l c a r e o u s f o r a m i n l f e r a i n th e l i v i n g a sse m b la g e s ( F i g u r e 2 1 ). R a ti o s o f l i v i n g to t o t a l sp ecim en s com puted s e p a r a t e l y f o r th e c a l c a r e o u s and n o n - c a lc a r e o u s sp e c im e n s i n e a c h a sse m b la g e ( F ig u r e 22) w ere u s e d to i n v e s t i g a t e th e d is c r e p a n c y b etw een th e p e r c e n ta g e s o f c a l c a r e o u s sp e c im e n s TABLE 1.— Numbers of internal organic linings of calcareous foraminlfera found at 13 stations. Depths and percentages of calcareous foraminlfera in the ‘ benthonlc assemblages are given for each station. Station Number 473 476 5 0 I 4 - 537 539 544 60K 62k 6h 7 6kg 672 673 7 1 6 Depth (meters) 3 6 80 3380 15^0 2190 560 2 6 20 U 6 i * o 2350 1^90 iQko 3 7 0 0 200 3170 Percentages of calcareous foraminlfera 35 k 2 0 3 16 3 0 22 3 X 8 1 1 Eponides tumidulus Linings 1 5 1 2 l 3 1 h 3 Whole Tests 0 0 0 2 0 0 1 0 5 Unindentifled linings 1 k 1 1 6 1 X = l e s s t h a n 1 p e r c e n t Figure 20 D epth D i s t r i b u t i o n o f th e P e r c e n ta g e s o f C a lc a re o u s S pecim ens i n T o ta l ( L if e p l u s Dead) B e n th o n ic A ssem blages P/B = P la n k to n ic s B e n th o n ic R a tio 78 BATHYMETRY (THOUSANDS O F M ETE R S) PERCENT CALCAREOUS IN TOTAL ASSEMBLAGE 0 50 100 0 50 100 2 - 4 - o SOUTH GEORGIA 5 - • SCOTIA SEA 30 p i ro o C D P/B = 0.44-0.93 ° P/B = 0-0.25 o SOUTH SANDWICH ISLANDS • SOUTH ORKNEY ISLANDS A WEDDELL SEA -4 V O Figure 21 D epth D i s t r i b u t i o n o f th e P e r c e n t a g e s o f C a lc a r e o u s B e n th o n ic s i n L iv in g F o r a m l n i f e r a l A sse m b la g es P/B = P l a n k to n i c :B e n t h o n ic R a tio 80 BATHYMETRY (THOUSANDS O F M E T E R S ) I - 3 - 4 - 5 - o 6H e 7J m N P E R C E N T C A L C A R E O U S IN L IV IN G F A U N A 50 ± 1 0 0 o SOUTH GEORGIA • SCOTIA SEA 0 J . 50 i i I f 11 r P/B= 0 - 0 .2 5 O P/B = 0 .9 3 A P/B = 2.2 o SOUTH SANDWICH ISLANDS • SOUTH ORKNEY ISLANDS A WEDDELL SEA 1 0 0 0 5 ( — 1 Figure 22 D epth D i s t r i b u t i o n o f L iv e :T o t a l R a tio s o f C a lc a re o u s and N o n -c a lc a re o u s Specim ens P/fe = P la n k to n ic :B e n th o n lc R a tio 82 BATHYMETRY (THOUSANDS O F M ETERS) 3 o c a> m ro ro 50 o 2 - 3 - 4 - 5 - 6 - SOUTH GEORGIA AND SCOTIA SEA 0 20 L IV E / TOTAL X 100 0 20 _L 40 60 -L P/B = 0-0.25 80 ± 1 0 0 o o o P/B = 0.93 > P/B* 2.2-88 o o NON-CALCAREOUS BENTHONICS • CALCAREOUS BENTHONICS WEDDELL SEA AND SOUTH SANDWICH AREA CD L O 84 i n l i v i n g and i n t o t a l a s s e m b la g e s . Maximum l i v e : t o t a l r a t i o s (X100) a r e 96 f o r c a l c a r e o u s sp e c im e n s an d 19 f o r n o n - c a l c a r e o u s s p e c im e n s . C o n s id e r in g t h e w id e s p re a d o c c u r r e n c e o f p a r t i a l l y d i s s o l v e d c a l c a r e o u s t e s t s , d i s s o l u t i o n o f em pty t e s t s a p p e a r s th e m o st l i k e l y e x p la n a t i o n f o r th e u n u s u a l l y h ig h l i v e : t o t a l r a t i o s o f c a l c a r e o u s s p e c i m ens. B e c a u se t h e sa m p le s a r e n o t u n if o r m , h a v in g b een c o l l e c t e d w ith b o t h c o r e s an d g r a b s , an d b e c a u s e s t a i n e d p r o t o p la s m i s m ore d i f f i c u l t t o d e t e c t i n th e a lm o s t opaque n o n - c a l c a r e o u s t e s t s th a n i n th e t r a n s p a r e n t o r t r a n s l u c e n t c a l c a r e o u s t e s t s , s i g n i f i c a n c e h a s b e en a t t r i b u t e d to d i f f e r e n c e s i n l i v e : t o t a l r a t i o s o f c a l c a r e o u s and n o n - c a l c a r e o u s sp e c im e n s o n ly when th e d i f f e r e n c e s a r e l a r g e ( a f a c t o r o f two o r m ore) and when t h e l i v e : t o t a l r a t i o (X100) f o r c a l c a r e o u s sp e c im e n s i s h ig h (m ore th a n 1 0) . R e g io n a l D i s t r i b u t i o n o f th e E v id e n c e f o r S o l u t i o n S o u th e rn and E a s t e r n S c o t i a R idge On t h e s l o p e s o f t h e s o u t h e r n and e a s t e r n S c o t i a R idge, n o n - c a l c a r e o u s b e n th o n l c f o r a m i n l f e r a d o m in a te (0 -5 3 c e n t c a l c a r e o u s ) a n d t h e d e e p e s t sam ple w ith more th a n 15 p e r c e n t c a l c a r e o u s b e n th o n i c s i s from 2350 m e te r s ( F ig u r e 2 0 ) . By c o n t r a s t , c a l c a r e o u s f o r a m i n l f e r a f r e q u e n t l y d o m in a te th e l i v i n g a s s e m b la g e s , and i f c a l c a r e o u s f o r a m l- n l f e r a f r e q u e n t l y d o m in a te t h e l i v i n g a s s e m b la g e s , and i f c a l c a r e o u s f o r a m i n l f e r a a r e p r e s e n t i n a s a m p le , th e y form a l a r g e r p r o p o r t i o n o f th e a sse m b la g e w h ic h was l i v i n g a t t h e tim e o f c o l l e c t i o n th a n o f th e t o t a l a s s e m b la g e ( F ig u r e 2 1 ) . T hus, c a l c a r e o u s .f o r a m i n l f e r a a r e 4 8 to 73 p e r c e n t o f t h e l i v i n g a s s e m b la g e s i n te n sa m p le s fro m above 2350 me t e r s i n w h ich th e y a r e o n ly 8 to 53 p e r c e n t o f t h e t o t a l a s s e m b la g e s . P l a n k to n i c f o r a m i n l f e r a a r e r a r e i n 27 o f t h e sa m p le s from t h i s p a r t o f th e S c o t i a R id g e ( p l a n k t o n i c : b e n - t h o n i c r a t i o = 0 - 0 . 2 5 ) and s l i g h t l y m ore a b u n d a n t i n t h r e e sa m p le s ( p l a n k t o n i c : b e n t h o n l c r a t i o = 0 , 4 4 - 0 . 9 3 ) . The sam p l e s w ith more p l a n k t o n i c f o r a m i n l f e r a h a v e a g r e a t e r r e l a t i v e p r o p o r t i o n o f c a l c a r e o u s b e n th o n l c f o r a m i n l f e r a th a n m o st n e a rb y sampleB from s i m i l a r d e p th s . L arg e l i v e : t o t a l r a t i o s a p p e a r t o i n d i c a t e a v e ry r a p i d s o l u t i o n r a t e . I n e i g h t sa m p le s from d e p t h s l e s s th a n 2350 m e t e r s , th e l i v e : t o t a l r a t i o (X100) f o r c a l c a r e o u s s p e c i mens r a n g e s from 33 to 96 i n d i c a t i n g t h a t t h e r e a r e l e s s th a n two and i n many c a s e s l e s s th a n one g e n e r a t i o n o f em pty c a l c a r e o u s t e s t s i n th e s e d im e n ts ( F ig u r e 2 2 ) . I n t h r e e o t h e r s a m p le s , how ev er, th e l i v e : t o t a l r a t i o (X100) i s o n ly 5 to 9 « Two o f t h e s e sa m p le s w ith s m a ll r a t i o s a r e from l e s s th a n 490 m e te rs p e rh a p s I n d i c a t i n g a lo w e r s o l u t i o n r a t e a t l e s s e r d e p th s c o m p a rab le to c o n d i t i o n s above t h e s h a llo w d e p th o f e f f e c t i v e c a r b o n a te s o l u t i o n i n th e R o ss Sea d e s c r i b e d by K e n n e tt ( 1 9 6 6) . 86 W id e sp re a d o c c u r r e n c e s o f c o rro d e d b e n th o n lc c a l c a r e ous sp e c im e n s s u p p o r t a h ig h s o l u t i o n r a t e . For exam p le, s o f t , f r i a b l e t e s t s o f C i b ic i d e s g r o s s e p u n c ta tu s and C as- s i d u l i n a s u b g lo b o s a w ere found a t s t a t i o n USC 539 and i n t e r n a l l i n i n g s w ere fo u n d a t s t a t i o n s USC 504, 537* 539* and 544. T hese a r e n o t i s o l a t e d ’ exam ples; th e y a r e q u o ted b e c a u se t h e s e sa m p le s w ere p r e s e r v e d i n a lc o h o l r e n d e r in g p o s t - c o l l e c t i o n s o l u t i o n l e s s l i k e l y th a n i n o t h e r sam ples w hich w ere p r e s e r v e d w ith b u f f e r e d f o r m a lin . N o rth e rn S c o t ia R idge In c o n t r a s t to c o n d it i o n s on th e s o u th e rn and e a s t e r n S c o t i a R id g e , c a l c a r e o u s f o r a m i n lf e r a do m inate b e n th o n lc as' se m b lag es i n n in e sa m p le s from d e p th s o f 320 to 2920 m e te rs on th e s lo p e s o u th o f S o u th G e o rg ia (6 0 -9 9 p e r c e n t c a l c a r e o u s ) , and i n t h r e e sam ples a lo n g 45°W from 2110 to 3470 m e te rs on t h e n o r t h e r n S c o t i a R idge an d in th e n o r th w e s te r n S c o t ia Sea (8 6 -9 7 p e r c e n t c a l c a r e o u s ) . P la n k to n ic s a re more a b u n d a n t th a n b e n th o n ic s i n n in e o f th e s e sam p les w h ile b e n th o n ic s outn um ber p l a n k t o n i c s i n t h r e e o f th e a s sem b lag es from above 750 m e te r s . The p la n k to n ic f o r a m l n if - e r a a r e g e n e r a l l y d e e p ly c o rro d e d . B ased on t r i a l s o f 100 o r more sp e c im e n s i n sam p les w ith more p l a n k t o n i c s th a n b e n th o n i c s , a b o u t 10 p e r c e n t o f th e p l a n k t o n i c s from s t a t i o n USC 460 (2110 m) a t 45°W and a b o u t 25 p e r c e n t o f th e sp ecim en s from s t a t i o n USC 685 (640 m) r e s i s t e d b re a k a g e 87 w h ile l i g h t p r e s s u r e o f a d i s s e c t i n g n e e d le b ro k e sp e c im e n s t e s t e d i n t h e o t h e r s a m p le s . Many o f t h e b e n t h o n i c s a r e d e e p ly c o r r o d e d i n t h e t h r e e sa m p le s fro m t h e S o u th G e o rg ia s lo p e w h ich h a v e m ore b e n t h o n i c s th a n p l a n k t o n i c s , a n d i n t e r n a l l i n i n g s o f E p o n id e s t u m i d u l u s ,w ere fo u n d i n t h e s o u th e rn m o s t c a l c a r e o u s sam p le a lo n g 45°W, b u t f r o s t e d w a l l s , p o s s i b l y c a u s e d b y l i g h t s o l u t i o n p i t t i n g , a r e t h e o n l y e v id e n c e o f c o r r o s i o n o f c a l c a r e o u s b e n t h o n i c s i n t h e r e s t o f t h e s e s a m p le s . The f o r a m i n l f e r a c o n s i d e r e d to be l i v i n g a t t h e tim e o f c o l l e c t i o n w ere s t u d i e d i n f o u r s a m p le s fro m d e p th s o f 1030 to 2290 m e te r s on t h e s lo p e s o u th o f S o u th G e o r g ia . I n t h e s e f o u r B am ples, t h e r a n g e i n p e r c e n t a g e o f c a l c a r e o u s f o r a m i n l f e r a i n t h e l i v e a s s e m b la g e i s 51 t o 89 p e r c e n t ( F ig u r e 21) a p p r o x im a tin g t h e r a n g e i n p e r c e n t a g e o f c a l c a r e o u s f o r a m i n l f e r a i n t h e t o t a l a s s e m b la g e w h ic h i s 6 l to 95 p e r c e n t . L i v e : t o t a l r a t i o s f o r c a l c a r e o u s f o r a m i n l f e r a a r e s i m i l a r to l i v e : t o t a l r a t i o s f o r n o n - c a l c a r e o u s fo ra m - i n i f e r a ( F ig u r e 2 2 ) ; t h u s , no d i f f e r e n t i a l d e s t r u c t i o n o f th e two k in d s o f t e s t s i s i n d i c a t e d . H ow ever, t h e r a t i o s , w h ich r a n g e fro m 3 to 2 3 * a lt h o u g h c o m p a ra b le to some o f t h e r a t i o s o b t a i n e d a t s i m i l a r d e p th s i n t h e G u lf o f C a l i f o r n i a ( P h l e g e r , 1 9 6 4 ), s h o u ld p r o b a b l y b e c o n s i d e r e d u n u s u a l l y h ig h b e c a u s e i n t h i s s t u d y two o r more c e n t i m e t e r s o f s e d i m ent from t h e t o p s o f t h e c o r e s w ere s t u d i e d r a t h e r th a n t h e u p p e r one c e n t i m e t e r a s i n p r e v i o u s s t u d i e s . The h ig h 88 r a t i o s m ea su re d i n sa m p le s from th e S o u th G e o rg ia s lo p e may s u g g e s t some d e s t r u c t i o n o f b o th c a l c a r e o u s and n o n - c a l c a r e o u s f o r a m i n i f e r a l t e s t s . Some d e s t r u c t i o n o f c a l c a r e o u s t e s t s i s l i k e l y , f o r th e p l a n k t o n i c t e s t s o c c u r r in g i n th e same s a m p le s .a r e d e e p ly c o rro d e d d e m o n s tra tin g t h a t c a r b o n a te was g o in g i n t o s o l u t i o n . T h at c e r t a i n a g g l u t i n a te d s p e c ie B may be e s p e c i a l l y s u s c e p t i b l e to p o st-m o rte m d e s t r u c t i o n was s u g g e s te d by B la n c - V e rn e t ( 1965) who n o te d u n u s u a l l y h ig h f r e q u e n c i e s o f a g g l u t i n a t e d f o r a m i n i f e r a . from th e A n t a r c t i c w h ich w ere s t a i n e d w ith r o s e b e n g a l, •and by B uzas ( 1 9 6 5 ) who made s i m i l a r o b s e r v a t i o n s on s p e c i mens from Long I s l a n d Sound. D e ep e r on th e S o u th G e o rg ia s l o p e , a t 3760 m e te r s , a d i f f e r e n c e b e tw ee n l i v e : t o t a l r a t i o s o f c a l c a r e o u s and o f n o n - c a l c a r e o u s b e n th o n ic f o r a m i n i f e r a d o e s e x i s t (F ig u re 2 2 ) , and i n t e r n a l l i n i n g s o f E p o n id e s tu m id u lu s o c c u r . T h e r e f o r e , th e lo w e r p e r c e n t a g e o f c a l c a r e o u s sp ecim en s (8 p e r c e n t ) i n th e t o t a l a sse m b la g e o f t h i s sam ple ( F ig u r e 20) a s com pared to s h a llo w e r S o u th G e o rg ia s lo p e sam p les a p p e a r s to b e c a u s e d n o t o n ly by few er c a l c a r e o u s sp e cim en s i n th e s t a n d in g c ro p (19 p e r c e n t c a lc a r e o u s ) (F ig u r e 2 1 ) , b u t a l s o by an I n c r e a s e d r a t e o f s o l u t i o n o f c a lc a r e o u s t e s t s . Deep Sea E x c e p tin g t h e c a l c a r e o u s a s s e m b la g e s i n th e n o r t h w e s t e rn S c o tia Sea and on th e S outh G e o rg ia s lo p e , 4 l assem b la g e s from below 2000 m e te rs a r e do m in ated by n o n - c a l c a r e - ous f o r a m in if e r a and o n ly f i v e by c a lc a r e o u s f o r a m in if e r a (53-98 p e r c e n t c a lc a r e o u s ) (F ig u re 2 0 ). P la n k to n ic f o ra m i n i f e r a a re r a r e i n m ost o f th e n o n - c a lc a r e o u s d e e p -s e a a s sem b lag es, b u t i n th e f i v e c a lc a r e o u s a sse m b la g e s th e y a r e from 2 .2 to 88 tim e s more ab u n d an t th a n b e n th o n ic s . The f o r a m in if e r a l i v i n g a t th e tim e o f c o l l e c t i o n w ere s t u d i e d i n tw elv e d e e p -s e a (d e e p e r th a n 2000 m e te rs ) non - c a lc a r e o u s a sse m b la g e s. N o n -c a lc a re o u s f o r a m in if e r a g en e r a l l y dom inate th e l i v i n g (F ig u re 21) a s w e ll a s th e t o t a l a sse m b la g e s. E x c e p tio n a lly h ig h l i v e : t o t a l r a t i o s o f c a l c a re o u s f o r a m in if e r a were t y p i c a l (F ig u re 22) and m ost o f th e i n t e r n a l l i n i n g s o f c a lc a r e o u s f o r a m i n if e r a came from d e e p -s e a asse m b la g es (T ab le l ) i n d i c a t i n g a h ig h r a t e o f s o l u t i o n . • Four o f th e f i v e sam ples w ith c a lc a r e o u s a sse m b la g e s from th e W eddell Sea a re s t a in e d w ith r o s e b e n g a l, b u t s t a i n e d specim ens were found i n o n ly two o f them . In b o th o f th e l a t t e r , th e l i v e a sse m b la g e s a r e do m inated by c a l c a r eous f o r a m in if e r a (one o f th e s e does n o t a p p e a r on F ig u re 21 b e ca u se o n ly f i v e s t a i n e d specim ens were found) and l i v e : t o t a l r a t i o s a re low. P la n k to n ic f o r a m i n if e r a i n two o f th e deep c a lc a r e o u s a sse m b la g e s a re d e e p ly c o rro d e d , b u t i n two o t h e r s (USC 513* USC 1074) c o r r o s io n i s u n ifo rm ly m oder a t e . In th e f i f t h assem b lag e (USC 6 1 7 ) , a com p lete ra n g e i n c o r r o s i o n w as n o t e d . ‘ I n th e a r e a s from w hich th e s e sa m p le s w ere t a k e n , c a l c a r e o u s t e s t s have e x p e r ie n c e d l e s s s o l u t i o n , i n g e n e r a l , th a n th o s e i n m ost o t h e r sam p les i n th e s o u th e r n p a r t o f t h e a r e a . V a rio u s c h a r a c t e r i s t i c s o f t h e f i v e W edd ell Sea sam p l e s c o n t a i n i n g c a l c a r e o u s a s s e m b la g e s t o g e t h e r w ith known o c c u r r e n c e s o f p r e - R e c e n t c a l c a r e o u s a s s e m b la g e s i n th e a r e a s u g g e s t t h a t t h e s e a s s e m b la g e s a r e r e l i c t . T h ree o f . th e sa m p le s (ELT 6 l 4 , 6 1 7 , 107*0 w ere from su b m a rin e r i d g e s o r m o u n ta in r a n g e s w here slu m p in g may e x p o se o l d e r s e d i m e n ts, o r c u r r e n t s may p r e v e n t d e p o s i t i o n . G o o d e ll ( 1 9 6 5 ) n o te d s c o u r i n c a l c a r e o u s s e d im e n ts i n b o tto m p h o to g r a p h s ta k e n n e a r USC 1074 w h ich i n d i c a t e d n o r t h e r l y c u r r e n t s . In a n o t h e r sa m p le (USC 513)* w h ich d o e s n o t a p p e a r to p o s s e s s any b a t h y m e t r i c p e c u l i a r i t y , th e f o r a m i n i f e r a a re so l a r g e t h a t s o r t i n g b y c u r r e n t seem s l i k e l y . O nly 6 p e r c e n t o f th e b e n th o n i c f o r a m i n i f e r a i n t h e sam ple a r e s m a ll enough t o p a s s th ro u g h a 125 m ic ro n ( 0 .1 2 5 mm) s c r e e n , w h e re a s i n a l l o t h e r s a m p le s o f t h i s s tu d y th e m a j o r i t y o f t h e b e n th o n ic f o r a m i n i f e r a a r e s m a ll enough t o do s o . The p l a n k t o n i c f o r a m i n i f e r a a r e a l s o l a r g e , b u t t h i s i s t r u e in o t h e r c a l c a r e o u s sa m p le s a s w e l l . As p r e v i o u s l y n o te d , no f o r a m i n i f e r a s t a i n e d w ith r o s e b e n g a l w ere fou n d i n two o f th e a s s e m b la g e s . T hose p r e s e n t i n two o t h e r s (USC 1074, 5 2 8) i n d i c a t e t h a t c a l c a r e o u s b e n th o n ic t e s t s a r e b e in g form ed a t p r e s e n t , b u t t h e i r p r e s e n c e d o es n o t n e g a te t h e h y p o t h e s is t h a t m ost o f th e c a l c a r e o u s t e s t s i n t h e s e sam p l e s a r e r e l i c t . In e v id e n c e , an i n c o n g r u i t y e x i s t s b e tw een th e l i v i n g and d e ad c a lc a r e o u s f o r a m i n i f e r a i n USC 528 w hich may i n d i c a t e m ixin g o f R e c e n t and r e l i c t assem b l a g e s . In t h i s sa m p le , N u t t a l i d e s u m b o n ife r a . a d o m in an t s p e c i e s i n o t h e r p re su m a b ly r e l i c t a s s e m b la g e s , c o m p ris e s 13 p e r c e n t o f th e t o t a l a sse m b la g e b u t i s u n r e p r e s e n te d i n t h e l i v i n g p o p u l a t i o n . T here a r e to o few s t a i n e d f o r a m i n i f e r a i n USC 1074 to e s t a b l i s h w h e th e r su c h a r e l a t i o n s h i p e x i s t s a t t h a t s t a t i o n a l s o . D is c u s s io n C a lc a re o u s s k e l e t o n s o f p l a n k t o n i c and b e n th o n ic fo ram i n i f e r a have a c c u m u la te d i n th e s e d im e n ts on th e n o r t h e r n S c o t i a R idge i n s p i t e o f e x te n s i v e s o l u t i o n . The s o l u t i o n i s e v id e n c e d by w id e s p re a d c o r r o s io n o f p l a n k t o n i c s k e l e t o n s w hich i s u n u s u a l i n th e a u t h o r ’ s e x p e r ie n c e when com p a re d to th e p r e s e r v a t i o n o f c a l c a r e o u s s k e l e t o n s i n b a t h - y a l d e p o s i t s from te m p e ra te and t r o p i c a l l a t i t u d e s . B ased on th e sam p les from one t r a v e r s e , a d e p th b o u n d a ry o f e f f e c t i v e c a r b o n a te s o l u t i o n a p p e a rs to o c c u r b etw een a p p ro x i m a t e l y 3000 and 3500 m e te rs on th e s lo p e o f th e S c o t i a R idge s o u th o f S o u th G e o rg ia . Above th o s e d e p th s p l a n k t o n i c and c a l c a r e o u s b e n th o n ic f o r a m i n i f e r a a r e m o d e r a te ly a b u n d a n t and l i v e : t o t a l r a t i o s a r e s i m i l a r f o r c a l c a r e o u s an d n o n - c a lc a r e o u s f o r a m i n i f e r a w h ile below th o s e d e p th s 92 t h e r e a r e few c a lc a r e o u s f o r a m i n i f e r a , l i v e : t o t a l r a t i o s f o r c a l c a r e o u s f o r a m i n if e r a a r e h ig h e r th a n f o r n o n - c a l c a re o u s f o r a m i n i f e r a , and some empty c a lc a r e o u s b e n th o n ic s k e l e t o n s a r e d e e p ly c o rro d e d . On th e s lo p e s o f th e s o u th e rn and e a s t e r n S c o tia . R id g e, ho w ev er, c a l c a r e o u s s k e l e t o n s a r e r e l a t i v e l y r a r e i n th e s e d im e n ts even th o u g h c a lc a r e o u s f o r a m i n if e r a domi n a te some l i v i n g b e n th o n ic a s s e m b la g e s . A v e ry r a p i d s o l u t i o n r a t e i s i n d i c a t e d i n m ost sa m p le s, a t l e a s t below 500 m e te r s ; t h u s , th e d e p th o f e f f e c t i v e c a r b o n a te s o l u t io n a p p e a rs to r i s e to w a rd s th e s o u th . S outh and e a s t o f th e c a lc a r e o u s a sse m b la g e s o f th e n o r th e r n S c o t i a R idge and a t d e p th s g r e a t e r th a n 2000 me t e r s , two k in d s o f f o r a m i n i f e r a l a sse m b la g e s a r e fo u n d . In th e k in d c h a r a c t e r i s t i c o f m ost sa m p le s, c a lc a r e o u s specim ens a r e r a r e , u s u a l l y c o n ta in p r o to p la s m , and , i f empty ( o r i n some c a s e s , even when th e y c o n ta in p ro to p la s m ) , th e y a r e u s u a l l y c o rro d e d . The s o l u t i o n r a t e , t h e r e f o r e , a p p e a rs h ig h ; b u t s in c e n o n - c a lc a r e o u s f o r a m i n if e r a g e n e r a l l y d o m in ate i n th e a sse m b la g e s t h a t were s t u d i e d f o r " l i v i n g " f o r a m i n i f e r a , th e t o t a l a sse m b la g e s w ould presum a b ly be d o m in a ted by n o n - c a lc a r e o u s f o r a m i n if e r a even i n th e a b s e n c e o f s o l u t i o n . I n f a c t , how ever, t h e r e I s c o n s i d e r a b l e e v id e n c e , a lth o u g h i n c o n c lu s iv e , t h a t th e s e c a l c a re o u s a sse m b la g e s a r e r e l i c t and a r e t h e r e f o r e n o t i n 93 e q u il i b r i u m w ith th e c a rb o n a te system i n th e w a te r above th e se d im e n t s u r f a c e . The s e v e re c o rr o s io n o f c a lc a r e o u s f o r a m i n i f e r a l s k e l e to n s o b se rv e d i n m ost sam ples from th e S c o tia and n o r th e r n W eddell S eas i s p ro b a b ly cau sed p r i m a r i l y by a g g re s s iv e , s o lv e n t a c t i o n o f A n t a r c t ic deep and bo ttom w a te rs w hich have been shown to be e x c e p ti o n a l l y u n d e r s a t u r a t e d i n c a lc iu m c a rb o n a te (Hood and B e r k s h ir e , 1 965) . In r e p o r t i n g m easurem ents o f c a rb o n a te s a t u r a t i o n ta k e n d u rin g C ru is e s 6 and 7 o f th e U .S .N .S . ELTANIN u s in g Bahama o o l i t e s a s s t a n d a r d s , Hood and B e rk s h ire p l o t t e d th e d e g re e o f s a t u r a t i o n a g a i n s t d e p th f o r 14 s t a t i o n s . A lthough th e m easu re m ents have n o t been c o r r e c t e d f o r th e e f f e c t o f p r e s s u r e w hich d e c r e a s e s s a t u r a t i o n w ith i n c r e a s in g d e p th (P ytkow icz and ConnorB, 1964; P y tk o w icz, 1965)» com parison o f th e s t a t i o n s showB t h a t a t any d e p th th e w a te r i s more s a t u r a t e d i n c a rb o n a te n o r t h o f th e conv ergence th an in m ost s t a t i o n s so u th o f th e co n v erg en c e . The w a te r i n B r a n s f i e l d S t r a i t s , how ever, i s a p p a r e n tly l e s s u n d e r s a t u r a t e d th a n in o t h e r sam ple a r e a s so u th o f th e c o n v e rg e n c e . In F ig u re 23, th e d e p th d i s t r i b u t i o n o f c a rb o n a te s a t u r a t i o n f o r one o f th e f i v e s t a t i o n s from n o r th o f th e A n t a r c t ic C onvergence i n D rake P assag e i s compared to th e d e p th d i s t r i b u t i o n o f c a rb o n a te s a t u r a t i o n f o r th r e e o f th e fo u r s t a t i o n s a lo n g 45°W lo n g itu d e so u th o f th e co n v erg en c e . The t h r e e s t a t i o n s from so u th o f th e conv ergence a r e from th e n o r th e r n , Figure 23 L e v e l o f C a lc iu m C a rb o n a te S a t u r a t i o n P l o t t e d A g a in s t D epth f o r S t a t i o n s N o rth an d S outh o f th e A n t a r c t i c C onvergence ( A f t e r Hood and B e r k s h i r e , 19^5) S t a t i o n E -6 -1 1 E -7 -2 E -7 -8 E -7 -1 3 ■ L a t • S 5* 5 4 °l6 » 60° 0 6 « 66° 27 ' Long.W 56° o4 » 4 4 ° 4 4 1 4 5 ° 25 * 4 5 0 4 6 1 94 N. OF ANTARCTIC CONVERGENCE NORTHERN SCOTIA SEA SOUTHERN SCOTIA SEA WEDDELL SEA CaCOg SAT. M/L x I0"4 _ T°C STATION E-6-11 STATION E - 7 - 2 STATION E -7-13 STATION E - 7 - 8 -2 1 to IOOO- f 2000- 3 0 0 0 - T °C 4 0 0 0 - ro 96 c e n t r a l , and s o u th e r n p a r t s o f th e a r e a o f t h i s I n v e s t i g a t i o n n e a r i t s w e s te r n e d g e . B e c a u se th e s e a w a te r a t s a t u r o m e tr y s t a t i o n E -7 -2 (a n d a l s o E -7 -4 n o t shown i n F ig u r e 2 3 ) from th e n o r t h e r n S c o t i a Sea i s a p p a r e n t l y a s u n d e r s a t u r a t e d i n c a r b o n a te a t a l l d e p th s a s t h a t a t s t a t i o n E -7 -8 from th e s o u th e r n S c o t i a S e a , i t i s n e c e s s a r y to c o n c lu d e e i t h e r t h a t th e few s a t u r o m e tr y s t a t i o n s do n o t a d e q u a te ly d e f i n e v a r i a t i o n s i n c a r b o n a te s a t u r a t i o n i n t h e a r e a o r t h a t o t h e r f a c t o r s e x p l a i n t h e d i f f e r e n c e s b e tw ee n t h e f o r a m i n i f e r a l a s s e m b la g e s on th e n o r t h e r n S c o t i a R idge and th o s e on th e s o u th e r n and e a s t e r n S c o t i a R id g e . P o s s i b l y th e Warm Deep L a y e r s o u th o f S o u th G e o rg ia i s l e s s u n d e r s a t u r a t e d i n c a r b o n a t e th a n i t i s a lo n g t h e s o u th e r n an d e a s t e r n S c o t i a R id g e . A t th e l e v e l o f maximum t e m p e r a tu r e (a b o u t 400 to 600 m e te r s ) s o u th o f S o u th G eo r g i a , t h e te m p e r a tu r e i s 2 .l4 ° C w h ile a lo n g th e s o u th e r n S c o t i a R id g e i t i s o n ly 0 .5 ° C . T hese te m p e r a t u r e s a p p ro a c h th e l i m i t s o f th e r a n g e o b s e r v e d a t t h i s l e v e l s o u th o f th e A n t a r c t i c C o n v e rg en c e. The t e m p e r a tu r e r a n g e i s s m a ll, h o w e v e r, and c o n s i d e r i n g th e l a c k o f I n f o r m a tio n on c o n c e n t r a t i o n s o f com ponents o f t h e c a r b o n a te sy s te m , i t i s p r e m a tu re to s p e c u l a t e on i t s e f f e c t on c a r b o n a te s o l u b i l i t y . A r e a l d i f f e r e n c e s i n t h e p r o d u c t i v i t y o f p l a n k t o n i c f o r a m i n i f e r a p o s s i b l y I n f l u e n c e th e d i s t r i b u t i o n o f c a l c a r e o u s a s s e m b la g e s . The lo n g e r g ro w in g s e a s o n beyond th e l i m i t s o f p ack i c e n e a r th e A n t a r c t i c C onvergence c o u ld he c o n d u civ e to h ig h e r p r o d u c t i v i t y t h e r e . P a r t i a l s o l u t i o n o f p l a n k t o n i c t e s t s a c c u m u la tin g on th e b o tto m c o u ld th e n i n c r e a s e th e a l k a l i n i t y o f th e i n t e r s t i t i a l w a te r and o f th e w a te r im m e d ia te ly above th e s e d im e n t-w a te r i n t e r f a c e . T hese w a te r s would th u s more c l o s e l y a p p ro a c h a s t a t e o f s a t u r a t i o n p e r m i tt i n g th e s k e l e t o n s o f c a lc a r e o u s b e n th o n ic f o r a m i n if e r a to b e p r e s e r v e d . Koczy (1953) h a s d e m o n s tra te d an i n c r e a s e in a l k a l i n i t y w ith d e p th v e ry n e a r th e b o tto m i n th e A t l a n t i c a n d In d ia n O ceans, and s e m is a tu r a te d b o tto m l a y e r s p r o t e c t i n g c a lc a r e o u s t e s t s from s o l u t i o n have been p o s t u l a t e d by P h le g e r , P a r k e r , and P ie r s o n (1953) and by B e rg e r ( 1 9 6 7) . A B e m ls a tu ra te d b o tto m l a y e r i s p ro b a b ly a f a c t o r i n th e p r e s e r v a t i o n o f c a lc a r e o u s f o r a m i n i f e r a l t e s t s i n some caB es, b u t t h e r e a r e so few p l a n k t o n i c fo ra m i n i f e r a i n some o f th e sam p les from th e s lo p e o f S o u th G eor g i a ( 0 .1 to 316 p l a n k t o n i c specim ens p e r gram i n f i v e sam p l e s ) t h a t m o d if ic a tio n o f th e e n v iro n m e n t n e a r th e se d im e n t s u r f a c e th ro u g h p a r t i a l s o l u t i o n o f p l a n k t o n i c s k e l e t o n s does n o t a p p e a r t o e x p la in why th e b e n th o n ic a sse m b la g e s a r ^ d o m in a n tly c a lc a r e o u s t h e r e . S ta n d in g c ro p s may p r o v id e c lu e s to p r o d u c t i v i t y , b u t u n f o r t u n a t e l y , th e o n ly a v a i l a b l e s tu d y o f l i v i n g p l a n k t o n i c f o r a m i n if e r a i n th e n o r th e r n S c o t ia Sea was b a se d on m a t e r i a l c o l l e c t e d i n th e a u s t r a l w i n t e r , n o t d u rin g th e p r o d u c tiv e summer se a so n (Be', i n p r e s s ) . High s ta n d in g c ro p s were found o v e r th e South Sandw ich T rench d u rin g l a t e summer, how ever, s u g g e s tin g t h a t a p p r e c i a b le p r o d u c tio n o f p la n k to n ic f o r a m i n if e r a does o c c u r i n some a r e a s w here t h e i r t e s t s a r e r a r e i n th e b o t tom s e d im e n ts . Assuming c a l c a r e o u s f o r a m i n if e r a a r e b e in g p ro d u ced and th e s e a w a te r i s u n d e r s a t u r a t e d i n c a lc iu m c a r b o n a te , t h e r e a r e a num ber o f f a c t o r s d is c u s s e d by A rrh e n iu s ( 1 9 6 3) w hich d e te rm in e w h e th e r c a lc a r e o u s t e s t s a cc u m u late i n th e s e d im e n ts . A h ig h r a t e o f s e d im e n ta tio n c o v e rin g th e s o l u b l e s k e l e t o n s and th u s p r o t e c t i n g them from th e s o lv e n t f a v o r s t h e i r p r e s e r v a t i o n , •w h ile e v o lu tio n o f carb o n d io x id e th ro u g h b a c t e r i a l o x i d a t i o n o f o rg a n ic m a t t e r i n th e s e d i m ents i n c r e a s e s th e r a t e o f d i s s o l u t i o n . F lu s h in g o f th e s e m is a tu r a te d b o tto m l a y e r by c u r r e n t s p e rm its f u r t h e r s o l u t i o n to o c c u r . L i t t l e i s known a b o u t th e r a t e s o f sed im en t a t i o n , b a c t e r i a l p r o c e s s e s in s e d im e n ts , o r b o tto m c u r r e n t s i n th e S c o tia Sea and n o r t h e r n W eddell S ea. The f a c t t h a t f o r a m i n i f e r a l a sse m b la g e s showing e v id e n c e o f v e ry h ig h s o l u t i o n r a t e s a t b a t h y a l d e p th s a lo n g th e s o u th e rn and e a s t e r n S c o t ia R idge o c c u r i n a v a r i e t y o f se d im e n ts su g g e s t s , how ever, t h a t s e d im e n ta tio n r a t e s and p o s s i b l y b a c t e r i a l p r o c e s s e s a r e a ls o v a r i a b l e i n th e s e s e d im e n ts . Some o f th e se d im e n ts a r e o f v o lc a n ic p a r t i c l e s and o t h e r s o f t e r r i g e n o u s p a r t i c l e s ; th e s i l t s c la y r a t i o ra n g e s from 1 .3 to 6 . 5 . D i f f e r e n c e s betw een th e abundance o f c a l c a r e o u s f o r a m i n if e r a on th e n o r th e r n S c o t ia R idge and on th e 99 s o u th e r n an d e a s t e r n S c o t i a R idge a r e more l i k e l y c a u s e d by f a c t o r s w hich can be e x p e c te d to show l a r g e B eale r e g i o n a l v a r i a t i o n s ; t h a t i s , t h e r a t e o f a c c u m u la tio n o f c a l c a r e o u s f o r a m i n i f e r a i s d e te rm in e d by th e b a la n c e b e tw ee n p r o d u c t i v i t y o f c a l c a r e o u s f o r a m i n i f e r a and th e u n d e r s a t u r a t i o n o f s e a w a t e r . W ith t h e a v a i l a b l e sam ple c o n t r o l i t i s p o s s i b l e o n ly to s p e c u l a t e on t h e s i g n i f i c a n c e o f t h e p re s u m a b ly r e l i c t W ed d e ll Sea c a l c a r e o u s a s s e m b la g e s . They s u g g e s t t h a t th e c a r b o n a t e c o m p e n sa tio n d e p th w h ich i s a p p a r e n t l y , a t p r e s e n t , no d e e p e r th a n 500 m e te r s was a t some tim e i n th e p a s t a lm o s t 4000 m e t e r s . D iatom s a r e v i r t u a l l y a b s e n t fro m th e c a l c a r e o u s segm ent o f c o re sam ple USC 516 a s th e y a r e from t h e n o n - c a l c a r e o u s se g m en t. The r a r i t y o f d ia to m s s u g g e s t s , a lt h o u g h i t d o e s n o t p r o v e , t h a t h i g h e r p r o d u c t i v i t y i s n o t r e s p o n s i b l e f o r th e p r e - R e c e n t a c c u m u la tio n o f p l a n k t o n i c t e s t s . Two a l t e r n a t i v e .e x p la n a t i o n s a r e t h a t A n ta r c t i c B o tto m W ater was p r e v i o u s l y l e s s u n d e r s a t u r a t e d i n c a r b o n a te th a n i t i s a t p r e s e n t o r t h a t c i r c u l a t i o n w as so slow when th e c a l c a r e o u s a s s e m b la g e s a c c u m u la te d t h a t a s e m i s a t u r a t e d b o tto m l a y e r p r o t e c t i n g th e c a l c a r e o u s s k e l e t o n s c o u ld d e v e lo p . B e ca u se th e W ed d ell Sea i s c u r r e n t l y t h e m ost I m p o r ta n t s o u rc e o f A n t a r c t i c B o tto m W a te r w hich flo w s o u t i n t o th e a d j a c e n t o c ea n b a s i n s a t t h e d e e p e s t l e v e l s , e i t h e r o f th e s e e x p l a n a t i o n s , i f t r u e , w ould have f a r r e a c h i n g i m p l i c a t i o n s . DISTRIBUTION OF PLANKTONIC FORAMINIFERA G e n e ra l S tu d ie s o f p l a n k t o n i c f o r a m i n i f e r a i n ‘ bottom s e d im e n ts ( B l a i r , 1 9 6 5) and i n sam p les o f l i v i n g p la n k to n (Chen and Be*, 19^5j Chen, 1 9 6 6; B o lto v s k o y , 1966a ; Be, i n p r e s s ) have shown t h a t th e A n t a r c t i c C onvergence i s an im p o r ta n t bound a ry betw een A n t a r c t i c and S u b a n t a r c ti c f a u n a s . S in c e th e A n t a r c t ic C onvergence a lm o s t c o in c id e s w ith t h e n o r th e r n boun dary o f th e s tu d y a r e a , o n ly A n t a r c t i c fa u n a s a r e o f • c o n ce rn h e r e . In b o tto m s e d im e n ts , A n t a r c t i c fa u n a s a re do m inated by G lo b ig e r in a p a c h y d e rm a , a lm o s t to th e e x c lu s io n o f o t h e r s p e c i e s . G. pachyderm a o c c u r s in 5^ s t a t i o n s from th e S c o tia and W eddell S eas a c c o u n tin g f o r a l l ab u n d an ces o f p la n k to n ic f o r a m i n i f e r a g r e a t e r th a n 200 specim ens p e r gram o f s e d im e n t. The s i n l s t r a l l y c o i l e d form o f t h i s s p e c ie s i n c r e a s e s r e l a t i v e to th e d e x t r a l form a s th e A n t a r c t i c C onvergence i s a p p ro a c h e d from th e n o r t h ; im m edi a t e l y s o u th o f t h e c o n v e rg e n c e , 99 to 100 p e r c e n t o f a l l specim ens i n b o tto m se d im e n ts a r e s i n i s t r a l ( B l a i r , 1 9 6 5) . A lso p e r s i s t e n t i n A n t a r c t i c fa u n a s i s th e m in u te , h i g h - s p i r e d G l o b l g e r l n l t a u v u la w hich o c c u rs i n 30 o f th e 100 i 101 s a m p le s, b u t t h e r e a r e n e v e r l a r g e num bers o f t h i s s p e c i e s i n a gram o f s e d im e n t. In l i v i n g p l a n k t o n i c fa u n a s G. u v u la i s more a b u n d an t s o u th o f th e co n v erg en ce th a n n o r th o f i t (B o lto v s k o y , 1966a ; Be^ i n p r e s s ) . Seven o t h e r s p e c i e s w hich o c c u r a s r a r e specim ens i n a few sam ples w ere: G lo b ig e r in a b u l l o i d e s 8 sam ples G l o b o r o t a l ia l n f l a t a 7 ” G lo b ig e r in a q u in q u e lo b a 3 " G l o b i g e r i n i t a g l u t i n a t a 3 1 1 G l o b o r o t a l ia t r u n c a t u l i n o i d e s 1 " G l o b o r o t a l ia s c i t u l a 1 " Chen and Be ( 1 9 6 5)* Chen ( 1966) , and Be* ( in p r e s s ) r e g a r d s m a ll, s p in o s e form s o f G. q u in q u e lo b a to be im p o r ta n t i n l i v i n g p l a n k t o n i c fa u n a s on b o th s i d e s o f th e c o n v e rg e n c e ; b u t Bouth o f th e c o n v erg en c e i t i s n o t a s a b u n d an t i n b o t tom se d im e n ts a s m ig h t be e x p e c te d from th e p r e v a le n c e o f l i v i n g sp ecim en s i n o v e r ly in g w a te r s . T here i s a c o n se n s u s i n p r e v io u s s t u d i e s t h a t th e o t h e r s i x s p e c ie s a r e S u b a n t-., a r c t i c —Be* ( in p r e s s ) r e p o r t e d t h a t S u b a n ta r c tic s p e c ie s can c r o s s th e A n t a r c t i c C onvergence an a v e ra g e d i s t a n c e o f 300 m ile s (560 km) b e f o r e th e y c o m p le te ly d is a p p e a r s o u th w ard . V a r i a t i o n s i n P la n k to n ic A ssem blages V a r i a t i o n s w ere n o te d i n r e l a t i v e fre q u e n c y o f G. u v u la , th e p re s e n c e o r ab sen ce o f S u b a n ta r c tic s p e c i e s , th e , fre q u e n c y o f l a r g e sp ecim en s o f G. p achyderm a, and th e f r e - 102 quency o f th e s i n i s t r a l form o f G. p a ch y d e rm a . S iz e and c o l l i n g f r e q u e n c i e s w ere m easured o n ly a t s t a t i o n s w here sp ecim en s o f G. pachyderm a w ere ab u n d an t s in c e I t was c o n s id e r e d n e c e s s a r y to c o u n t a t l e a s t 500 specim ens f o r s i g n i f i c a n t r e s u l t s . The s i z e d i s t r i b u t i o n was d e te rm in e d by s i e v in g th e sam ple and c o u n tin g th e s p e c i mens r e t a i n e d on th e 250 m ic ro n , 125 m ic ro n , and 62 m icron s c r e e n s . None o f th e sp e cim en s was l a r g e enough to rem ain on th e 500 m icron s c r e e n . I f n e c e s s a r y , an a l i q u o t o f 500 to 1000 specim ens was ta k e n w ith a m o d ifie d O tto m ic ro s p l i t t e r b e fo r e s i e v i n g . The t e s t d im e n sio n m easured i s a p p ro x im a te ly th e a x i s o f i n t e r m e d i a t e l e n g t h , r a t h e r th a n th e a x i s o f g r e a t e s t l e n g t h a s i s u s u a l l y o b ta in e d when t e s t d ia m e te rs a r e m easured w ith o c u l a r m ic ro m e te rs . R e la t i v e f r e q u e n c ie s o f s p e c i e s w ere com puted i f 25 o r more specim ens were e n c o u n te r e d when th e sam ple was s t u d i e d ; i f p la n k to n ic f o r a m i n if e r a w ere r a r e r th a n t h i s , th e o c c u rr e n c e o f e ac h s p e c ie s was n o te d , b u t no s i g n i f i c a n c e was a t t r i b u te d to r e l a t i v e f r e q u e n c i e s (T ab le 2 ) . By th e s e v a r i a b l e s th e R e c e n t, o r p o B S ib ly su b -R e c e n t, o c c u r re n c e s o f a b u n d a n t p l a n k t o n i c f o r a m i n i f e r a a lo n g th e n o r th e r n S c o tia R idge a r e d i s t i n g u i s h a b l e from th e p r o b a b ly r e l i c t a sse m b la g e s w ith a b u n d a n t p l a n k t o n i c f o r a m i n if e r a i n th e n o r th e r n W eddell Sea (F ig u re 2 4 ). A t h i r d a r e a w ith p la n k to n ic a sse m b la g e s d i f f e r e n t from e i t h e r o f th e s e l i e s i n th e e a s t e r n S c o t ia S e a . Figure 24 S iz e and C o ilin g R a tio s o f G lo b ig e r in a pachyderm a and L o c a tio n o f P la n k to n ic A ssem blages w ith High • R e l a t i v e F re q u e n c ie s o f G l o b i g e r i n i t a u v u la 103 io4 . BATHYMETRY IN METERS AVERlOE OF FOUR STATIONS 100 % I M - 99% S • 0 0 0. SOUTH SANOWICH ISLANOS v \ SOUTH ORKNEYS GLOBIGERINA PACHYDERMA > 5 0 0 SPECIMENS IM A M , IN ' ' . MICRON! _oo . «S"2 PLANKTONIC FORAMINIFERA > 25 SPECIMENS 96%S • GLOBIGERINA PACHYDERMA DOMINANT . . «!• SIZE DISTRIBUTION CORE 516 4 0 -4 9 CM, > 4 0 w ftIO ▲ OLOBIOERINITA UVULA I?~B O % ' 1 •9% S' C0ILIN0 RATIO turmeric — • FIGURE 24 105 N o rth e rn S c o tia Ridge P la n k to n ic f o r a m i n i f e r a l asse m b la g es i n b o tto m s e d i m ents im m e d ia te ly s o u th o f th e A n t a r c t ic C onvergence a re r e l a t i v e l y w e ll known th ro u g h th e i n v e s t i g a t i o n by B l a i r ( 1965) . B l a i r s t u d i e d sam ples c o l l e c t e d by th e U .S .N .S . ELTANIN from th e n o r th e r n S c o tia Ridge a s w e ll a s from D rake P a ssag e and th e S outh P a c i f i c . The a sse m b la g e s from th e n o r th e r n S c o tia R idge a n a ly z e d i n t h i s s tu d y , t h e r e f o r e , a r e f a m i l i a r s ta n d a r d s a g a i n s t w hich th o s e found f a r t h e r s o u th i n th e S c o tia and W eddell Seas may be com p a r e d . Prom t h i s a r e a e i g h t asse m b la g es w ith ab u n d an t p la n k to n ic f o r a m i n if e r a were B tu d ie d , b u t s i z e o f G. p a c h y derma was m easured i n o n ly seven b e ca u se one o f th e sam ples (USC 686) was ta k e n w ith a B lak e Traw l from w hich s m a lle r specim ens may have been l o s t . I n 't h e s e e i g h t a sse m b la g e s, c o i l i n g o f G. pachyderm a i s a lm o st t o t a l l y s i n i s t r a l (99 to 100 p e r c e n t ) , and s p e c i-. mens l a r g e r th a n 250 m ic ro n s a re 0 to 2 p e r c e n t i n s ix sam ples and 6 p e r c e n t i n one sam ple. G l o b i g e r i n i t a u v u la i s p r e s e n t i n s i x o f th e e i g h t sam p les, w ith a maximum r e l a t i v e f r e q u e n c y o f 4 p e r c e n t . S u b a n ta r c tic s p e c ie s o c c u r i n f o u r o f th e e i g h t sa m p le s, b u t c u m u la tiv e ly a r e n e v e r more th a n 1 p e r c e n t o f any asse m b la g e. 106 E a s t - c e n t r a l S c o t ia Sea Of th e 27 sam p les from w hich more th a n 25 sp ecim en s o f p la n k to n ic f o r a m i n if e r a w ere o b ta in e d , G l o b l g e r l n l t a u v u la i s l e s s th a n 4 p e r c e n t i n 22 and more th a n 33 p e r c e n t i n f i v e . F our o f th e s e l a t t e r f i v e a r e from th e S c o tia Sea s o u th o f S o u th G e o rg ia , an d th e o t h e r from j u s t n o r t h e a s t o f S outh G e o rg ia , E x p re s s e d a s number o f sp ecim en s p e r gram o f s e d im e n t, th e ab undance o f G. u v u la i s no more i n th e s e f i v e sam ples ( 1 .2 to 81 sp ecim en s/g ram ) th a n i n sam p l e s w ith a b u n d an t p l a n k t o n i c f o r a m i n i f e r a from th e n o r t h e rn S c o tia R idge (0 to 67 s p e c im e n s /g ra m ). In th e re m a in d e r o f th e a r e a , G. u v u la i s v e ry r a r e ( l e s s th a n 1 s p e c im e n / g ra m ). * N o rth e rn W eddell Sea More th a n 500 sp ecim en s o f G. pachyderm a w ere o b ta in e d from each o f s ix sam p les i n th e n o r th e r n W eddell S ea, The a sse m b la g es o f f i v e o f th e s e sam ples have c h a r a c t e r i s t i c s , d is c u s s e d ab o v e, w hich s u g g e s t t h a t th e y a re e i t h e r r e l i c t a c c u m u la tio n s o r c o n ta in rew o rk ed sp ecim en s from o l d e r s e d im e n ts . The p l a n k t o n i c s o f th e s i x t h sam ple (USC 6 2 4 ), w hich were l e s s a b u n d a n t th a n th e b e n th o n l c s , may o r may n o t be m odern. I n a d d i t i o n , th e p l a n k t o n i c f o r a m i n if e r a w ere s t u d i e d i n t h e lo w e r s e c t i o n o f th e c o re USC 516, th e u p p e r p o r t i o n o f w hich c o n ta in e d an asse m b la g e o f n o n - ic a lc a r e o u s f o r a m i n i f e r a . The p la n k to n ic f o r a m in if e r a i n th e s e sam ples a r e f a r d i f f e r e n t from th o s e on th e n o r th e r n S c o tia R id g e. I n th e f i r s t p l a c e , th e p r o p o r t io n o f s i n i s t r a l specim ens o f G. pachyderm a i s lo w e r: 96 to 98 p e r c e n t r a t h e r th a n 99 to 100 p e r c e n t . A lthou gh t h i s d i f f e r e n c e i s s m a ll, i t i s s i g n i f i c a n t . From c h a r t s p re p a r e d by Van d e r P la s and Tobi ( 1965) , p e r c e n ta g e s o f 99 p e r c e n t d e te rm in e d from c o u n ts o f 500 specim ens a re a c c u r a te to l e s s th a n 1 p e r c e n t w ith a 95 p e r c e n t l e v e l o f c o n fid e n c e . In th e second p l a c e , th e specim ens a re g e n e r a l l y e x c e p ti o n a l l y l a r g e . In f i v e s u r f a c e sam p les, from 15 to 53 p e r c e n t o f th e specim ens o f G. pachyderm a were l a r g e r th a n 250 m ic ro n s in d ia m e te r . In one sam ple (USC 6 l 4 ) , how ever, o n ly 4 p e r c e n t o f th e s p e c i mens were t h i s l a r g e . A lthough th e h i g h e s t fre q u e n c y o f la r g e specim ens o c c u rs i n th e sam ple which was p ro b a b ly c u r r e n t s o r t e d (ELT 513)* a s i m i l a r fre q u e n c y o c c u rs i n th e lo w er p o r t io n o f th e c o re ELT 516 (47 p e r c e n t ) . A n o th er f e a t u r e o f theBe sam ples i s th e n e a r a b sen ce o f p l a n k to n ic s p e c ie s o t h e r th a n G lo b ig e rin a p achyderm a. A lthough a few specim ens o f G. u v u la and G. b u l l o l d e s o c c u r a t one s t a t i o n (USC 5 2 8 ), th e o t h e r sam p les, b o th s u r f a c e and s u b s u r f a c e , c o n ta in o n ly G. pachyderm a. 108 C lim a tic S i g n i f i c a n c e o f th e W ed d ell Sea R e l i c t P l a n k to n i c A ssem b lag es The c h a r a c t e r i s t i c s o f p l a n k t o n i c f o r a m i n i f e r a l assem b l a g e s i n b o tto m s e d im e n ts ch an g e w ith i n c r e a s i n g so u th l a t i t u d e . S u b a n t a r c t i c s p e c i e s become r a r e r and t h e p r o p o r t i o n o f s i n i s t r a l sp e cim en s i n p o p u l a t i o n s o f G lo b ig e r in a p achyderm a i n c r e a s e s ( B l a i r , 19&5) • '3 ^ie s i z e o f sp ecim en s o f G. p ach yderm a a l s o i n c r e a s e s ( J . P. K e n n e tt, p e r s o n a l c o m m u n ic a tio n ). A l l t h r e e o f t h e s e c h a n g e s a r e r e l a t e d to te m p e r a tu r e and any o r a l l o f them may be te m p e ra tu re c o n t r o l l e d . The i n t e r p r e t a t i o n o f p a le o te m p e r a tu r e s i s f a c i l i t a t e d when a s u b -R e c e n t p l a n k t o n i c a sse m b la g e i s s i m i l a r i n a l l t h r e e c h a r a c t e r i s t i c s to a R e c e n t asse m b la g e.. The p l a n k t o n i c f o r a m i n i f e r a l a s s e m b la g e s w hich have b een p r e v i o u s l y s t u d i e d i n d e t a i l a r e from n o r t h o f th e A nt a r c t i c C on vergence and a s h o r t d i s t a n c e s o u th o f i t . The W edd ell Sea c a l c a r e o u s a s s e m b la g e s , h o w ev er, a r e l i k e none o f t h e s e . In b o tto m s e d im e n ts from a r e a s n e a r th e A n ta rc t i c C o n v e rg en c e, a s s e m b la g e s o f p l a n k t o n i c f o r a m i n i f e r a i n w hich 96 to 98 p e r c e n t o f th e sp e c im e n s o f G. pachyderm a a r e s l n i s t r a l l y c o l l e d have s i g n i f i c a n t f r e q u e n c i e s o f Sub a n t a r c t i c B p e c ie s ( B l a i r , 1 9 6 5)• *n c o n t r a s t th e W eddell Sea p l a n k t o n i c a s s e m b la g e s i n w hich 96 t o 98 p e r c e n t o f th e sp e cim en s o f G. pachyderm a a r e s i n i s t r a l , have no sp ecim en s o f S u b a n t a r c t i c s p e c i e s . An ev en more s t r i k i n g c h a r a c t e r i s t i c o f t h e W ed d e ll Sea a s s e m b la g e s i s t h e v e ry l a r g e p r o p o r - 109 t l o n o f sp ecim en s o f G. pachyderm a g r e a t e r th a n 250 m ic ro n s I n d ia m e te r . T here a r e n o t a s many l a r g e sp ecim en s o f t h i s s p e c i e s In sa m p le s from th e N o rth e rn S c o t i a Sea o r I n sam p l e s from j u s t s o u th o f th e A n t a r c t i c C onvergence I n t h e P a c i f i c Ocean s e c t o r s t u d i e d b y K e n n e tt ( p e r s o n a l communi c a t i o n ) . O nly I n th e R oss Sea* I n o n e sa m p le , d id K e n n e tt f i n d a s i m i l a r p r o p o r t i o n o f sp e c im e n s o f G. pachyderm a l a r g e r th a n 250 m ic ro n s (13 p e r c e n t ) . B ecause o f th e l a c k o f d e t a i l e d know ledge o f m odern p o p u l a t i o n s o f p l a n k t o n i c f o r a m i n i f e r a from n e a r th e A n t a r c t i c C o n tin e n t, I n t e r p r e t a t i o n s o f th e W ed d ell Sea r e l i c t c a l c a r e o u s a s s e m b la g e s m ust re m a in s p e c u l a t i v e . N e v e rth e l e s s , th e c h a r a c t e r o f th e s e a s s e m b la g e s , e s p e c i a l l y th e h ig h f r e q u e n c i e s o f l a r g e sp e c im e n s, s u g g e s t s t h a t th e y l i v e d I n s u r f a c e w a te r s o f v e ry low t e m p e r a t u r e . L arg e s i z e I s t y p i c a l o f many c o ld - b lo o d e d organ!sm B i n p o l a r e n v iro n m e n ts — g ro w th i s slo w , b u t r e p r o d u c t i o n i s d e la y e d and l i f e i s lo n g (G u n te r, 1 9 5 7 ). F o r th e same r e a s o n s , th e b e n th o n ic f o r a m i n if e r a n Ammonia b e c c a r i i t e p i d a (C ush man) becom es l a r g e r and h a s more cham bers when grown a t suboptim um te m p e r a tu r e s i n l a b o r a t o r y c u l t u r e (B radshaw , 1 9 5 7 ). L ik e w is e , s p e c i e s o f E lp h id lu m from th e w e st c o a s t o f N o rth A m erica i n c r e a s e i n s i z e w ith a d e c r e a s e i n tem p e r a t u r e and an I n c r e a s e i n d e g re e s n o r t h l a t i t u d e ( N lc o l, 1 9 ^ ) • A s l i g h t l y d i f f e r e n t i n t e r p r e t a t i o n was o f f e r e d by B l a i r ( 1965) who s u g g e s te d t h a t e x t r a o r d i n a r i l y l a r g e s p e c - 110 im ens o f p l a n k t o n i c f o r a m i n i f e r a r e p r e s e n t "a p o r t i o n o f th e p o p u l a t i o n w hich had n o t a c h ie v e d r e p r o d u c t iv e m a t u r it y d u rin g th e A u s t r a l summer, when e n v iro n m e n ta l c o n d i t i o n s a r e m ost f a v o r a b le f o r r e p r o d u c t i o n ." Slow grow th may c o n tin u e i n t o th e w i n t e r m onths e v e n t u a l l y p ro d u c in g a l a r g e r t e s t . I f t h i s i n t e r p r e t a t i o n i s c o r r e c t , h ig h f r e q u e n c ie s o f l a r g e sp ecim en s o f G. pachyderm a may be i n d i c a t i v e o f v e ry s h o r t p e r i o d s f a v o r a b le f o r r e p r o d u c t io n . As a co n seq u e n ce o f a l i g h t - a b s o r b i n g i c e c o v e r d u rin g m ost o f th e y e a r , a d e q u a te l i g h t f o r a h ig h l e v e l o f p rim a ry p ro d u c t i v i t y , p o s s i b l y a s tim u lu s to r e p r o d u c tio n i n G. p a c h y derm a, i s l i m i t e d to a s h o r t tim e a t th e p e a k o f summer. The r e l i c t p l a n k t o n i c f o r a m i n i f e r a l p o p u l a t i o n s , t h e r e f o r e , s u g g e s t t h a t th e te m p e ra tu re and p e r i o d o f i c e c o v e r i n th e n e a r s u r f a c e w a te r s o f th e W eddell Sea a t th e tim e when c a lc a r e o u s t e s t s a c c u m u la te d i n b o tto m se d im e n ts was n o t g r e a t l y l e s s th a n a t th e p r e s e n t tim e when no c a l c a re o u s t e s t s a r e a c c u m u la tin g . F u rth e rm o re , i t i s u n l i k e l y t h a t p r o d u c t i v i t y was much h ig h e r th e n th a n now i f th e abundance o f d iato m s i s any i n d i c a t i o n o f p r o d u c t i v i t y : th e y a r e a s r a r e i n th e r e l i c t c a lc a r e o u s sam p les a s i n n e a rb y n o n - c a lc a r e o u s sa m p le s. I f th e s e c o n c lu s io n s a r e c o r r e c t , s i g n i f i c a n t m o d if i c a t io n s i n th e d e e p e r l e v e l s o f th e w a te r column have o c c u r r e d . DISTRIBUTION OP BENTHONIC FORAMINIFERA G e n e ra l B e n th o n ic f o r a m i n i f e r a w ere B tu d ie d i n 90 sam ples c o l l e c t e d from a w ide v a r i e t y o f e n v iro n m e n ts . D epths ra n g e d from 200 to 7700 m e te r s ; se d im e n t t e x t u r e ra n g e d from g r a v e l to c l a y ; and d ia to m s composed th e b u lk o f some sam p l e s w h ile th e y w ere a b s e n t i n o t h e r s . A lth o u g h th e ra n g e i n w a te r p r o p e r t i e s i s s m a ll, th o s e d i f f e r e n c e s w hich e x i s t d e f in e w a te r m asses w h ich o r i g i n a t e d i n s e p a r a t e a r e a s , had u n iq u e h i s t o r i e s , and w ere t r a n s p o r t e d i n t o th e a r e a by d i f f e r e n t c u r r e n t s . T hese w a te r s a r e h i g h ly u n d e r s a t u r a t e d in c a lc iu m c a r b o n a te , b u t a p p a r e n t l y more so i n some a r e a s th a n i n o t h e r s . Where e n v iro n m e n ts a r e a s d i v e r s e as t h i s , v a r i e t y In b e n th o n ic a sse m b la g e s i s e x p e c te d . W e ll-d e v e lo p e d d e p th z o n es w ere found on th e s l o p e s and d i s t i n c t b i o to p e s p a t t e r n e d th e a b y s s a l se a f l o o r s . I t was n e c e s s a r y to b a s e t h i s s tu d y p r i m a r i l y upon t o t a l a sse m b la g e s b e c a u s e th o s e few sam p les a n a ly z e d f o r l i v in g f o r a m i n if e r a w ere w id e ly s c a t t e r e d , and i n some c a s e s l i v i n g sp ecim en s w ere so r a r e t h a t s i g n i f i c a n t numbers c o u ld n o t be c o u n te d . N e v e r t h e l e s s , th e l i v i n g f o r a m i n if e r a l stu d y was a v a l u a b l e a d ju n c t i n t h a t th e l i v i n g and 111 112 t o t a l aBBemblages c o u ld be compared i n some sa m p le s. Thus in some c a s e s th e d e g re e to which th e t o t a l a sse m b la g e s were d i s t o r t e d by d e s t r u c t i o n o f some s p e c i e s , by dow nslope d is p la c e m e n t o f specim ens o r by o t h e r f a c t o r s , c o u ld be e s tim a te d . The m ost im p o rta n t f a c t o r d i s t o r t i n g t o t a l a sse m b la g es was s o l u t i o n w hich d i f f e r e n t i a l l y d e s tr o y e d c a lc a r e o u s t e s t s , a lth o u g h u n d e r s a t u r a t i o n o f th e e n v iro n m en t i n c a l cium c a r b o n a te may i t s e l f a ls o be a f a c t o r a f f e c t i n g th e d i s t r i b u t i o n o f l i v i n g f o r a m i n if e r a . B ecause o f th e e f f e c t o f s o l u t i o n , i t h a s been n e ce sB a ry to a p p ro a ch th e a n a l y s i s o f s o l u b l e and i n s o l u b l e s p e c ie s s e p a r a t e l y . A lthoug h o r i g i n a l l y a m a t t e r o f e x p e d ie n c y , t h i s m ethod h a s shown s i g n i f i c a n t d i f f e r e n c e s i n th e d i s t r i b u t i o n s o f c a lc a r e o u s and n o n - c a lc a r e o u s f o r a m in if e r a w hich a p p e a r u n r e l a t e d to s o l u t i o n o f empty c a lc a r e o u s t e s t s . Some im p o rta n t c h a r a c t e r i s t i c s o'f th e b e n th o n ic a s sem b lag es a re t h e i r d i v e r s i t y and th e s ta n d in g c ro p . O th er c h a r a c t e r i s t i c s , th e abundance o f f o r a m i n if e r a i n th e B ed i- m e n ts, and th e r e l a t i v e p r o p o r t io n s o f c a lc a r e o u s and non- c a lc a r e o u s f o r a m i n if e r a , have a lr e a d y been d i s c u s s e d . D i v e r s i ty The te rm , d i v e r s i t y , h a s been a p p lie d to two d i f f e r e n t c o n c e p ts , one o f w hich i s sim p ly th e number o f s p e c ie s o c - c u rln g i n a fa u n a . The o t h e r a tte m p ts to e x p re s s th e e v en 113 n e s s , o r l a c k o f I t , w ith w hich f r e q u e n c i e s o f s p e c i e s a r e d i s t r i b u t e d i n f o r a m i n i f e r a l a s s e m b la g e s . One m easure o f t h e l a t t e r c o n c e p t i s th e r e c i p r o c a l o f th e d i v e r s i t y s t a t i s t i c s u g g e s te d by Sim pson (1949)* w here N i s th e t o t a l num ber o f sp e cim en s c o u n te d , n.^ th e ab u n d an ce o f th e i t h s p e c i e s , and k i s th e number o f B p e c ie s . A ger ( 1 9 6 3) recom m ended S im p so n ’s s t a t i s t i c f o r a p p l i c a t i o n to f o s s i l p o p u l a t i o n s w h ile G ibson (19^6) u s e d i t to s tu d y d i v e r s i t y i n t o t a l f o r a m i n i f e r a l a sse m b la g e s i n M i s s i s s i p p i Sound. G ibson a l s o re v ie w e d and d is c u s s e d th e p r i n c i p l e s u n d e r l y i n g v a r i a t i o n s i n d i v e r s i t y i n l i v i n g p o p u l a t i o n s , b u t th e a p p l i c a t i o n o f theB e p r i n c i p l e s to t o t a l a s s e m b la g e s i s p r o b a b ly q u e s t i o n a b l e b e c a u s e , i n t h i s s tu d y a t l e a s t , d i v e r s i t y i n l i v i n g p o p u l a t i o n s was found to be som ewhat l e s s th a n i n t o t a l a sse m b la g e s (T a b le s 2 and 3 ) . S im p s o n 's s t a t i s t i c i s u s e d h e re a s an e m p i r ic a l m eas u r e to c h a r a c t e r i z e t o t a l b e n th o n lc f o r a m i n i f e r a l assem b l a g e s . A low num ber i n d i c a t e s t h a t m ost o f th e sp ecim en s i n an a s se m b la g e b e lo n g to a few s p e c i e s , w h ile a h ig h num ber i n d i c a t e s t h a t t h e sp e cim en s o f an a ssem b lag e a re d i s t r i b u t e d among a l a r g e r num ber o f s p e c i e s none o f w hich o c c u r s a t a h ig h fre q u e n c y . k N (N -l) 114 D i v e r s i t y was found to r a n g e from 1 .5 4 to 2 6 . 3 . I n g e n e r a l , i t i n c r e a s e s w ith d e p th on t h e s lo p e s o f th e S c o t i a R idge r e a c h in g a maximum on t h e lo w e r s lo p e below 2000 me t e r s (F ig u re 2 5 ). C h a r a c t e r i s t i c v a lu e s o f d i v e r s i t y a r e a s s o c i a t e d w ith e ac h a b y s s a l b i o t o p e a n d w ith th e t r e n c h b io to p e (T a b le 2 ) . S ta n d in g Crop I n F ig u re 26 s ta n d in g c ro p s a r e g iv e n a s th e num ber o f 2 i n d i v i d u a l s l i v i n g on 10 cm o f s e a b o tto m w h ich e q u a ls th e a re a sam pled by th e g r a v i t y c o r e s . The u p p e r 2 cm was s t u d i e d i n 20 c o re sa m p le s and th e u p p e r 5 cm o r more i n s ix c o re s a m p le s. S in c e f o r a m i n i f e r a have b een r e p o r t e d d e e p e r th a n 2 cm i n s e d im e n ts ( B o lto v s k o y , 1966b ) , t h i s d i f f e r e n c e i n c o re l e n g t h c o u ld be s i g n i f i c a n t . S ta n d in g c ro p s c o u ld n o t be com puted f o r t h e P e t e r s e n g ra b sam p les b e c a u s e th e a r e a sam pled was u n c e r t a i n . T h ere a r e no p r e v io u s s t u d i e s o f s ta n d in g c ro p s o f b e n th o n ic f o r a m i n i f e r a i n t h e A n t a r c t i c a lth o u g h two s t u d i e s have r e p o r t e d l i v i n g sp ecim en s (U ch io , 1960b, B la n c - V e r n e t, 1 9 6 5) . I t i s d i f f i c u l t to g e n e r a l i z e on so few sa m p le s s p r e a d o v e r such a v a s t a r e a . T here i s a s u g g e s t i o n , h ow ever, t h a t a lo n g th e S outh Sandw ich Arc B ta n d ln g c ro p s a r e h i g h e r above 1000 m e te rs (144 to 180 sp e c im e n s p e r 10 cm2 ) th a n d e e p e r, and t h a t below 1000 m e te r s th e y a r e somewhat g r e a t e r h e r e (56 to 180 sp ecim en s p e r 10 cm2 ) th a n on th e s lo p e Figure 25 D i v e r s i t y (S im p so n 's In d e x ) P l o t t e d a g a i n s t Depth 115 SIMPSONS DIVERSITY INDEX 116 5 1 10 _L- 15 1 20 25 —L 1000- v > x U J U J2000- z x £ 3 0 0 0 -1 U l Q 4 0 0 0 - • • • • 5000- F IG U R E 25 Figure 26 S ta n d in g Crop (S p ecim en s p e r 10 s q u a re c e n t i m e t e r s ) 117 118 40* BATHYMETRY . IN METERS •000' »»• SOUTH SANOWICH 4 0 0 ISLANOS .32 •0 * A K T S H C T IC 40* STANDING CROP NUMBER PER 10 CM FIGURE 2 6 119 s o u th o f S o u th G e o rg ia (36 to 66 sp e c im e n s p e r 10 cm2 ) . A l th o u g h s ta n d in g c r o p s a r e g e n e r a l l y lo w e r on b a s i n f l o o r s th a n on s l o p e s , t h e h i g h e s t one m ea su re d (400 sp e c im e n s p e r p 10 cm ) i s from t h e c e n t e r o f t h e S c o t i a B a s i n . F o u r sam p l e s from t h e W ed d ell Sea h a v e v e r y s m a ll l i v i n g p o p u la t i o n s (1 to 9 sp e c im e n s p e r 10 cm2 ) . A n a ly s is o f o n ly th e u p p e r c e n t i m e t e r o f c o r e s a s i n p r e v i o u s s t u d i e s may r e v e a l s l i g h t l y lo w e r s t a n d in g c ro p s th a n s tu d y o f th e u p p e r 2 cm o r m o re, i f f o r a m i n i f e r a l i v e a t d e e p e r l e v e l s i n t h e s e d im e n t. As a f i r s t a p p r o x im a tio n , h o w ev er, s ta n d in g c r o p s b elo w 2000 m e te r s i n t h i s a r e a a r e s i m i l a r t o , and so m etim es h i g h e r t h a n , th o s e b e lo w 1000 fathom B (1830 m) i n t h e G u lf o f C a l i f o r n i a ( 2 -6 2 s p e c im e n s / sam p le) s t u d i e d b y P h l e g e r ( 1 9 6 4 ) . None o f th e p o p u l a t i o n s a t l e s s e r d e p th s a lo n g t h e S c o t i a R id g e a r e a s h ig h a s some o f t h o s e from s i m i l a r d e p th s i n t h e G u lf o f C a l i f o r n i a and o f f San D iego (U c h io , 1960a ) . B a th y m e tr ic Z o n a tio n Two c a l c a r e o u s f o r a m i n i f e r a l d e p th z o n a t io n s a r e i d e n t i f i e d , one f o r t h e s l o p e s o u th o f S o u th G e o rg ia and th e o t h e r f o r t h e s o u th e r n and e a s t e r n S c o t i a R id g e . B e ca u se g e o g ra p h ic d i f f e r e n c e s a r e l e s s m arked i n n o n - c a l c a r e o u s a s se m b la g e s from v a r i o u s p a r t s o f t h e S c o t i a R id g e , o n ly one n o n - c a l c a r e o u s f o r a m i n i f e r a l d e p th z o n a tio n i s I d e n t i f i e d . 120 C a lc a re o u s B a th y m e tric Z o n a tio n S lo p e S o u th o f S o u th G e o rg ia N ine sam ples i n t h e t r a v e r s e a c r o s s th e s o u th e r n s lo p e o f S o u th G e o rg ia r a n g in g i n d e p th from 330 to 2930 m e te r s a r e d o m in ated by c a l c a r e o u s f o r a m i n i f e r a . The s h a l lo w e s t s t a t i o n o f t h e t r a v e r s e (2 0 0 m) an d t h e d e e p e s t (3700 m) a r e dom in ated by n o n - c a l c a r e o u s f o r a m i n i f e r a . An u p p e r s lo p e f a u n a l zone from < 330 m e te r s to > 750 m e te r s i s c h a r a c t e r i z e d by t h e s e f i v e sp e c ie B w h ich c u m u la tiv e ly t o t a l e d more th a n 70 p e r c e n t o f th e f o r a m i n i f e r a l assem b l a g e s (F ig u re 2 7 ): A n g u lo g e rin a e a r l a n d i A s tro n o n io n e c h o l s i . B u llm in a a o u l e a t a C a s s i d u l lo n o i d e s p a r k e r l a n u s F u rs e n k o in a f u s i f o r m i s Ten c a l c a r e o u s s p e c i e s have t h e i r u p p e r b a th y m e tr ic l i m i t s a t 640 m e t e r s . E x a m in a tio n o f a p r e l i m i n a r y b a th y m e tr ic c h a r t o f th e s lo p e c o m p iled from d e p th s and l o c a t i o n s g iv e n i n t h e h o u r ly d a ta s h e e t s o f th e U .S .N .S . ELTANIN s u g g e s t t h a t t h i s sam ple (USC 6 8 5 ) was ta k e n from a b a n k to p . T h is i n t e r p r e t a t i o n i s s u p p o r te d by th e v e r y h ig h p r o p o r t i o n o f p l a n k t o n i c f o r a m i n i f e r a and l a r g e f o r a m i n i f e r a l num bers (T a b le 6 ) i n th iB sa m p le . I t s f a u n a l p e c u l i a r i t i e s a r e b e l i e v e d r e l a t e d to i t s u n u s u a l to p o g r a p h ic p o s i t i o n r a t h e r th a n to i t s d e p th . Figure 27 D epth D i s t r i b u t i o n o f C a lc a re o u s F o ra m in ife ra on th e S lo p e S o u th o f S outh G eo rgia 121 122 CUMULATIVE FREQUENCY c o B C bJ H k l S X » - o. u a 60 1 0 0 CASSIOULINOIOES CRASSA O O f 1000 2000 U J u _1 1 1 1 3000' 3700 STATION NUMBER 673 675 674 685 676 679 MEAN 01 A. IN mm 0.032 0.125 0.50 680 681 686 682 672 FIGURE 27 123 A sam ple from 10 30 m e te r s a p p e a re d t r a n s i t i o n a l fro m th e u p p e r s lo p e f a u n a l zone to fa u n a s o f th e lo w e r s l o p e . A. echo 1 s i , B. a c u l e a t a , an d F. f u s i f o r m i s w ere a s a b u n d a n t i n t h i s sam ple a s i n some from s h a llo w e r d e p th s , b u t A n g u lo g e rin a e a r l a n d i a n d , e s p e c i a l l y , C. p a r k e r i a n u s o c c u r r e d a t lo w e r f r e q u e n c i e s t y p i c a l o f t h e i r o c c u r r e n c e s a t g r e a t e r d e p th s . I n t h i s sam ple G y ro id in a -s u b p l a n u l a t a an d N o n io n e lla i r i d e a , two s p e c i e s c h a r a c t e r i s t i c o f th e d e e p e r sa m p le s , a r e a b u n d a n t. T h is was th e s h a l lo w e s t a b u n d a n t o c c u r r e n c e o f G. s u b p l a n u l a t a , b u t 'N . i r i d e a i s a d o m in a n t i n one s h a l lo w e r s t a t i o n (USC 6 8 5 ) . I n th e lo w e r f a u n a l zone (>1500 m ), E il o h e d r a w e d d e l- l e n s l B , G. s u b p l a n u l a t a , an d N. i r i d e a a r e d o m in an t s p e c i e s . E p o n id e s tu m id u lu s , a c o s m o p o lita n a b y s s a l s p e c i e s h a s i t s u p p e r d e p th l i m i t i n t h i s p r o f i l e a t 1500 m e te r s . M e lo n ls p o m p i l i o i d e s i s p r e s e n t o n ly a t 2930 m e te r s . The u p p e r s lo p e f a u n a l zone c o rre s p o n d s w e ll to t h e u p p e r p a r t o f th e Warm Deep L ay e r c h a r a c t e r i z e d by h ig h tem p e r a t u r e s and low oxygen ( F ig u r e 2 7 ). S edim ent t e x t u r e a p p e a r s to e x e r t no c o n t r o l o v e r th e f a u n a l z o n e s. E a s t e r n an d S o u th e rn S c o t i a R id ge One f a u n a l b o u n d a ry a t 1500 to 1600 m e te rs i s r e c o g n i z e d i n t h i s a r e a . From 370 o r 490 m e te r s to 1600 m e te r s t h r e e s p e c i e s m ore p e r s i s t e n t and a b u n d a n t th a n a l l o t h e r 124 c a l c a r e o u s form s I n b o th t o t a l a s s e m b la g e s (T a b le 2) and p a r t i c u l a r l y I n l i v i n g f a u n a s (T a b le 3 ) a r e : E l l o h e d r a w e d d e l i e n s is E p l s t o m l n e l l a e x lg u a F u r s e n k o in a e a r l a n d l E llo h e d r a w e d d e lle n s ls and E p l s t o m l n e l l a e x lg u a a r e a ls o s i g n i f i c a n t s p e c i e s I n a b y s s a l a s s e m b la g e s . O th e r s p e c i e s a re l o c a l l y a b u n d a n t, b u t a r e n o t s u f f i c i e n t l y p e r s i s t e n t to be o f u s e I n d e f i n i n g z o n a l a s s e m b la g e s . Two s p e c i e s w hich h av e t h e i r u p p e r d e p th l i m i t s a t 1590 m e te rs (ELT 504) I n t h i s a r e a an d a r e p ro m in e n t In d e e p e r sa m p le s, more so I n l i v i n g fa u n a s th a n I n t o t a l a sse m b la g e s a r e : E p o n ld e s tu m ld u lu s M e lo n ls c f . M. a f f i n i s I m p o r ta n t d i f f e r e n c e s e x i s t b etw een t h i s z o n a tio n and th e one e s t a b l i s h e d f o r t h e s lo p e s o u th o f S o u th G e o rg ia I s l a n d . Only th e v e s t i g e s o f t h e u p p e r s lo p e f a u n a l zone c h a r a c t e r i z e d on th e S o u th G e o rg ia s lo p e by an overw helm ing p re p o n d e ra n c e o f 5 s p e c i e s can b e r e c o g n iz e d I n t h i s a r e a . C a s s i d u l in o i d e s p a r k e r i a n u s o c c u r s a s s i n g l e sp e c im e n s i n • two sa m p le s, and F u r s e n k o in a f u s i f o r m l s o c c u r s a t o n ly one s t a t i o n . On th e o t h e r h a n d , E ll o h e d r a w e d d e l l e n s ls I s im p o r t a n t a t much s h a llo w e r d e p th s th a n on th e S o u th G e o rg ia s l o p e . 125 N o n -c a lc a r e o u s B a th y m e tric Z o n a tio n R e p r e s e n t a t i v e a sse m b la g e s o f n o n - c a lc a r e o u s s p e c i e s w ere o b t a i n e d a t a g r e a t e r number o f s t a t i o n s th a n a sse m b l a g e s o f c a l c a r e o u s s p e c i e s and c o n s e q u e n tly c o u ld be zoned i n g r e a t e r d e t a i l . U pper and lo w e r b a th y m e tr ic l i m i t s o f a l l s i g n i f i c a n t s p e c i e s and th e b a th y m e tr ic c h a r a c t e r i s t i c s o f th e m ost im p o r ta n t and p e r s i s t e n t s p e c i e s s u g g e s t se v en b a th y m e tr ic b o u n d a r i e s . The m ost im p o r ta n t phenomenon w ith i n c r e a s i n g d e p th , how ev er, i s a c u m u la tiv e dow nslope d e c r e a s e i n b a t h y a l s p e c i e s c o n c u r r e n t w ith a c u m u la tiv e i n c r e a s e i n a b y s s a l s p e c i e s . ThiB c o m p le te ly a l t e r s th e a s p e c t o f a s s e m b la g e s o v e r th e b a th y m e tr ic i n t e r v a l 1300 to 2200 m e te r s . B a th y m e tric B o u n d a rie s An o v e r a l l view o f u p p e r and lo w er b a th y m e tr ic l i m i t s o f n o n - c a lc a r e o u s s p e c i e s can be o b t a i n e d by e x am in in g th e c u m u la tiv e num ber o f s p e c i e s added to o r d e l e t e d from t h e fa u n a w ith i n c r e a s i n g d e p th (F ig u re 2 8 ). Only s p e c i e s o c c u r r i n g i n more th a n f i v e sam ples a r e c o n s id e r e d e x c e p t f o r two s p e c i e s w hich a r e r e s t r i c t e d to th e s h a l lo w e s t sam p les and may t h e r e f o r e have few o c c u r r e n c e s b e c a u s e o n ly th e deep end o f t h e i r d i s t r i b u t i o n was sa m p le d . S i m i l a r e x c e p t i o n s o f s p e c i e s o c c u r r i n g i n th e d e e p e s t sa m p le s a r e u n n e c e s s a r y . T h is a p p ro a c h shows t h a t s p e c i e s a r e added Figure 28 C um u lative Number o f N o n -c a lc a re o u s S p e c ie s Added to and D e le te d from th e Fauna w ith I n c r e a s in g D epth 126 CUMULATIVE NUMBER OF SPECIES 20 40 SO 80 100 1000- SHALLOWEST OCCURRENCE 3 0 0 0 - DEEPEST ’ OCCURRENCE 5 0 0 0 - 6 0 0 0 - FIGURE 28 128 r a p i d l y w ith d e p th above 560 m e te rs due p r i m a r i l y to few s p e c i e s (9 to 14) In th e f o u r s h a llo w e s t sam p les fo llo w e d by a sam ple w ith many s p e c i e s (26) a t 490 m e te r s . Prom 560 to 2500 m e te r s s p e c i e s a r e added w ith d e p th a t th e re m a rk a b ly c o n s t a n t a v e ra g e r a t e o f 2 .3 s p e c i e s p e r 100 m e te r s . • O nly f o u r s p e c i e s have t h e i r u p p e r b a th y m e tr ic l i m i t s b e low 2500 m e t e r s . On th e o t h e r hand, o n ly n in e s p e c i e s h av e d is a p p e a r e d from th e fa u n a w ith i n c r e a s i n g d e p th a t 2500 m e te r s . B e ca u se few s p e c i e s a r e a b s e n t a s s p e c i e s w ith d e e p e r h a b i t a t a p p e a r , d i v e r s i t y i n c r e a s e s w ith d e p th . B e low 4100 m e te r s , h ow ever, th e r a t e a t w hich s p e c i e s hav e t h e i r lo w e r d e p th l i m i t s i n c r e a s e s . These d e p th s c o r r e s pond to th e d e e p e s t b a s i n f l o o r s . O nly f i v e sam p les w ith f o r a m i n i f e r a w ere p r e s e n t below 4700 m e te r s from deep b a s i n s an d th e t r e n c h . The im p o rta n c e o f a l l th e s e s p e c i e s , how ever, i s n o t th e sam e, and to c o n s i d e r them so i s to o b sc u re a z o n a tio n b a s e d on th o s e s p e c i e s w hich o c c u r c o n s i s t e n t l y o v e r r e s t r i c t e d d e p th s a t f r e q u e n c i e s i n th e b e n th o n ic a s s e m b la g e s o f g r e a t e r th a n 3 p e r c e n t . To s u g g e s t a z o n a tio n , t h e r e f o r e , 35 su c h s p e c i e s h ave b een s e l e c t e d t o g e t h e r w ith a n o th e r , Reophax s u b f u s l f o r m i s , w hich h a s been i n c lu d e d b e c a u s e i t i s a v e ry p e r s i s t e n t , a lth o u g h r a r e , b a th y a l s p e c i e s , ( F ig u r e 2 9 ). F o u r.s p e c le B w hich o c c u r c o n s i s t e n t l y o v e r a l a r g e b a th y m e tr ic i n t e r v a l a r e a l s o in c lu d e d f o r c o m p a ris o n . F u rth e rm o re , two i n t e r e s t i n g m o rp h o lo g ic a l Figure 29 G e n e r a liz e d D epth D i s t r i b u t i o n s o f I m p o r ta n t N o n -c a lc a r e o u s S p e c ie s 129 SPECIES SPIROPLECTAMMINA BIFORMIS TEXTULARIA EARLANPI AMMOFLINTINA ARCENTEA MILIAMMINA ARENACEA-LATA PORTATROCH. ANTARCTICA -W IESHERI PSEUOOBOLIVINA ANTARCTICA REOPHAX SUBFUSIFORMIS TROCHAMMINA MULTICAM-INTERM CANARIENSIS VERNEUILINA MINUTA LOMOSPIRA CHAROIOES TEXTULARIA WIESNERI PSAMMOSPHAERA EUSCA CRIBRQSTOMOIDES SUBGLOBOSUS GAUORYINA PAUPERATA SACCAMMIHA TUBULATA TROCHAMMINA SOROSA REOPHAX SP TROCHAMMINA OUAORILOBA AMMOBACULITES FILIFORMIS AMMOMARGINULINA ENSIS EGGERELLA PARKERAE VAR. 8 MARTINOTTIELLA ANTARCTICA s o L O A n i i U M B IL . TRITAXIS INHAERENS _CRIBROSTOMOIDES SPHAERILQCULUS AMMOBACULITES FOLIACEOUS FOLIACE RECURVA PUSILLA CONOTROCHAMMINA KENNETTI AOERCOTRVMA GLOMERATUM CONOTROCHAMMINA BULLATA - HAPLOPHRAGMOIDES PARKERAE ^ S R t a t r o c h a m m in a ELtANINI F IG U R E 2 9 v a r i a t i o n s a l s o a p p e a r to h a v e b a th y m e t r i c s i g n i f i c a n c e . I n d e e p e r w a te r s A m m o b acu lites f o l l a c e o u s d e v e lo p s a c o n c a v o - convex p l a n i s p i r e an d a l o n g i t u d i n a l l y f o l d e d u n i s e r i a l p o r t i o n su ch t h a t i t r e s e m b le s an o r i e n t e d so u p sp o o n ( P I . IV , P i g . 6 ) . T h is form w h ic h h a s b e e n c o u n te d s e p a r a t e l y a s A. f o l l a c e o u s form a r e c u r v a was fo u n d a t a b y s s a l d e p th s th r o u g h o u t th e a r e a i n a w ide v a r i e t y o f e n v ir o n m e n ts . A m m obaculites f i l i f o r m i s o c c u r r e d c o n s i s t e n t l y o n ly below 2300 m e te r s , and a t th o s e d e p th s th e d i a m e t e r o f t h e p l a n i s p i r e was s m a ll ( .0 3 6 mm t o .0 9 9 mm). The h i g h e s t r e l a t i v e f r e q u e n c y a t w hich t h i s s p e c i e s o c c u r r e d (14 p e r c e n t ) , how e v e r , was a t i t s s h a l l o w e s t o c c u r r e n c e , o n ly 560 m e te r s (USC 5 3 9 ) , and t h e r e th e d i a m e t e r o f i t s p l a n i s p i r e r a n g e d from 0 .0 7 2 to 0 .1 2 6 mm w ith a m ed ian d i a m e t e r o f 0 .0 9 0 mm. Of t h e 7 d e p th b o u n d a r ie s th e one a t 2100 to 23OO m e te r s a p p e a r s to be th e m ost s i g n i f i c a n t . A b a th y m e tr ic b o u n d a ry a p p e a r s t o e x i s t o v e r t h e d e p th r a n g e o f 260 to 560 m e te r s w h ic h c o r r e s p o n d s to t h e p h y s i o g r a p h i c b o u n d a ry b e tw e e n s h e l f a n d s l o p e . A l a r g e num ber o f s p e c i e s w ere o b s e r v e d t o h a v e t h e i r u p p e r d e p th l i m i t s h e r e (F ig u r e 2 8 ) , b u t m ost w o u ld p r o b a b l y h a v e b e en fo u n d a t s h a llo w e r d e p th s i f more sam pleB h a d b e en a v a i l a b l e . Two sp e c ie B w hich b e g in a t 490 m e te r s an d a r e p a r t i c u l a r l y p e r s i s t e n t and a b u n d a n t b e lo w t h i s d e p th a re s H aplophragm o i de s p a r k e r a e P o rta tro c h a m m ln a e l t a n l n a e 132 A s p e c i e s common a t 200 m e te rs an d a b s e n t b elo w 330 m e te r s w as: S p lro p le o ta m m in a b i f o r m i s A b o u n d a ry a t 1200 to 1300 m e te r s i s m arked b y t h e h i g h e s t o r h i g h e s t p e r s i s t e n t o c c u r r e n c e o f : C r ib r o s to m o id e s s u b g lo b o s u s G a u d ry in a p a u p e r a t a ~ Trochamm ina s o r o s a R eophax sp . A by t h e lo w e r l i m i t o f : T e x t u l a r i a e a r l a n d i and by a dow nslo pe d e c r e a s e i n r e l a t i v e f re q u e n c y o f : A m m o flin tin a a r g e n t e a M illam m lna sp p . A b o u n d a ry a t 2100 to 2300 m e te r s was r e c o g n i z e d b y t h e f i r s t o c c u r r e n c e s o f : C rib r o s to m o id e s s p h a e r i l o c u l u s C. u m b i l i c a t u l u s s o l d a n i i Cyclamm lna p u s l l l a M a r t i n o t t l e l l a a n t a r e t i c a P l a o o p s i l i n e l l a a u r a n t i a c a T r i t a x i s in h a e r e n s b y t h e h i g h e s t p e r s i s t e n t o c c u r r e n c e s o f : G lo m o sp ira c h a r o i d e s Psam m osphaera f u s c a Ammobacu11t e s f l l l f o r m i s A m m om arglnulina e n s l s Saccammina tubul'a't'a 133 by t h e d e e p e s t o r d e e p e s t p e r s i s t e n t o c c u r r e n c e s o f : M illam m lna a r e n a c e a A m m o flin tin a a r g e n t e a C r ib r o s to m o id e s a r e n a c e a Reophax s u b f u s i f o r m ! s A d e p th b o u n d a ry a t 2800 to 3100 m eterB a p p l i e s o n ly to t h e s lo p e s w e s t o f t h e S o u th O rkney I s l a n d s . S p e c ie s w h ich have t h e i r lo w e r d e p th l i m i t s d e e p e r i n th lB a r e a th a n i n o t h e r a r e a s a r e : P o rta tro c h a m m in a w i e s n e r i P s e u d o b o liv in a a n t a r c t i c a Trocham m ina m u lt i c a m e r a t a A m in o r b o u n d a ry a t 3100 to 3200 m e te r s i s r e c o g n iz e d by t h e s h a l lo w e s t c o n s i s t e n t o c c u r r e n c e s o f : Ammobacu11t e a f o l l a c e o u s form a r e c u r v a C onotrocham m ina k e n n e t t l A d e p th b o u n d a ry a t 3500 to 3700 m e te r s d e f i n e s th e d e e p e s t o r d e e p e s t c o n s i s t e n t o c c u r r e n c e s o f theB e s p e c i e s w h ich a r e common o r p e r s i s t e n t on t h e f l o o r o f t h e S c o t i a S ea: C r ib r o s to m o id e s u m b i l i c a t u l u s s o l d a n i i E g g e r e l l a p a r k e r a e v a r . B H a p lo p h ra g m o id e s c a n a r i e n s l s G a u d ry ln a p a u p e r a t a A b o u n d a ry from 4400 to 4700 m e te r s g e n e r a l l y c o i n c i d e s w ith th e s i l l s o f b a s i n s and t h e t r e n c h . I m p o r ta n t s p e c i e s 134 w ith t h e i r d e e p e s t o r d e e p e s t c o n s i s t e n t o c c u r r e n c e s h e r e a r e : A m m om arginulina e n s l s Cyclam m lna p u s l l l a H aplophragm o1 de s p a r k e r a e M a r t i n o t t i e l l a a n t a r c t i c a Trocham m ina l n c o n s p lc u a Trocham m ina s o r o s a and a s p e c i e s w h ich a t t a i n s I t s g r e a t e s t r e l a t i v e f r e q u e n c y a t g r e a t e r d e p th s I n th e S o u th Sandw ich T re n c h I s : C onotrocham m ina k e n n e t t i B a th y a l a n d A b y s s a l A ssem b lag es A s i g n i f i c a n t f a u n a l c h a n g e -o c c u rs b e tw ee n d e p th s o f a p p r o x im a te ly 1500 and 2000 m e te r s w h ereb y a g ro u p o f s p e c i e s d o m in a n t above 1500 m e te r s I s a lm o s t c o m p l e t e l y r e p l a c e d b y a n o th e r g ro u p o f s p e c i e s d o m in a n t b elo w 2000 m e te r s . To i l l u s t r a t e t h i s , th e n o n - c a l c a r e o u s s p e c i e s o c c u r r i n g In more th a n f i v e sa m p le s w ere d i v i d e d I n t o t h r e e g r o u p s . S p e c ie s I n t h e b a t h y a l g ro u p o c c u r p r i m a r i l y abo ve 2000 m e te r s , w h ile th o s e i n t h e a b y s s a l g ro u p o c c u r p r i m a r i l y b elo w 2000 m e t e r s . The t h i r d , o r n o n - d e f i n i t i v e , g ro u p I s p e r s i s t e n t o r a b u n d a n t b o th above and b elow 2000 m e t e r s . The r e l a t i v e f r e q u e n c i e s o f th e t h r e e g r o u p s p l o t t e d a g a i n s t d e p th f o r f o u r a r e a s a lo n g t h e S c o t i a R id g e a r e shown i n F ig u r e 3 0 . The s p e c i e s I n e a c h g ro u p a n d t h e i r o c c u r r e n c e s a r e shown i n T a b le 2 . The t h r e e g ro u p s a r e a d m i t t e d l y o f Figure 30 C u m u la tiv e F r e q u e n c i e s o f B a t h y a l , A b y s s a l, and N o n - d e f i n i t i v e S p e c ie s P l o t t e d a g a i n s t D ep th 135 DEPTH IN METERS o c 3) m w o SOUTH GEORGIA 0 20 40 60 80 100% 5 0 0 - 1000- 1500- 2000 - 2 5 0 0 - 3 0 0 0 - 350 0- 4 0 0 0 SOUTH SANDWICH ARC B - N A' SOUTHERN SOUTH ORKNEY ISLANDS AND EAST 0 20 40 .60 80 100% SCOTIA RIDGE WEST OF SOUTH ORKNEY ISLANDS BATHYL SPECIES NON-DEFINITIVE SPECIES ABYSSAL SPECIES i-* < J 0 a\ 137 a r b i t r a r y c o m p o s itio n , th e s p e c i e s i n e a c h b e in g c h o sen to p ro d u c e a d e s i r e d e f f e c t . The s i g n i f i c a n c e o f th e f a u n a l c h a n g e , h o w ev er, i s i n d i c a t e d b y t h e f a c t t h a t sp e c im e n s o f t h e n o n - d e f i n i t i v e g ro u p o f s p e c i e s c o m p ris e d l e s s th a n 50 p e r c e n t o f th e n o n - c a l c a r e o u s f o r a m i n i f e r a i n a l l b u t sev en a s s e m b la g e s t h r e e o f w h ich w ere from d e e p e r th a n 5000 me t e r s . The f a u n a l change o c c u r s a t r e m a r k a b ly s i m i l a r d e p th s th r o u g h o u t th e S c o t i a R id g e e x c e p t i n t h e a r e a w e s t o f th e S o u th O rkney I s l a n d s w here f o u r sa m p le s from b elo w 2000 me t e r s hav e h ig h f r e q u e n c i e s o f b a t h y a l s p e c i e s . T h ree o f t h e s e sa m p le s a r e from th e s o u th s i d e o f t h e r i d g e and one i s from t h e n o r th s i d e . Two s p e c i e s , P s e u d o b o liv ln a a n t a r c - . t i c a and Trochamm ina m u lt i c a m e r a t a , p r i m a r i l y a c c o u n t f o r t h e h ig h f r e q u e n c i e s o f b a t h y a l s p e c i e s w h ic h o c c u r d e e p e r th a n 2000 m e te rs i n t h i s a r e a , b u t o t h e r b a t h y a l s p e c i e s a r e a l s o p r e s e n t . S in c e t h e b a t h y a l s p e c i e s P, a n t a r c t i c a , T. m u lt i c a m e r a t a , and C r ib r o s to m o id e s a r e n a c e a w ere l i v i n g i n a t l e a s t two o f t h e s e s t a t i o n s (USC 537* 544) (T a b le 3 ) , th e d e p r e s s io n o f th e b a t h y a l f a u n a l zone h e r e i s n o t c a u s e d by dow nslope d is p la c e m e n t o f t e s t s . C om parison w ith O th e r D ep th Z o n a tlo n s E ig h t z o n a tlo n s o f A n t a r c t i c f o r a m i n i f e r a l a s s e m b la g e s h a v e b een p r e v i o u s l y p u b l i s h e d . C om parison o f t h e d e p th z o n a t lo n s p ro p o s e d h e r e w ith t h o s e p r o p o s e d by p r e v i o u s 138 w o r k e r s ( F ig u r e 3 1 ) I n d i c a t e s c o n s i d e r a b l e a g re e m e n t a s w e l l a s some d i f f e r e n c e s . U ch lo ( 1960b ) and S a ld o v a ( 1 9 6 1 ) d e s c r i b e d b a t h y a l faunaB w h ic h w ere d o m in a te ly c a l c a r e o u s , and th u s t h e i r z o n a t l o n s c a n be com pared to t h a t r e c o g n iz e d on th e s o u t h e r n s l o p e o f S o u th G e o r g ia . The f a u n a l b o u n d a ry t r a n s i t i o n a l o v e r t h e i n t e r v a l > 750 to < 1500 m e te rs on t h e S o u th G e o rg ia s l o p e a p p e a r s c o m p a ra b le to one a t 850 m eterB r e c o g n iz e d b y U chio an d on e t r a n s i t i o n a l o v e r th e i n t e r v a l 500 t o 1000 m e te r s I d e n t i f i e d b y S a id o v a . Among th e s p e c i e s c o n s i d e r e d t y p i c a l o f t h e u p p e r zone by S a id o v a w ere C as- s i d u l i n o i d e s p a r k e r i a n u s , A n g u lo g e rin a a n g u lo s a (=A. e a r - l a n d i ) . a n d A s tr o n o n io n s p . ( = A stro n o n lo n e c h o l s i ? ) , t h r e e o f th e d o m in a n t s p e c i e s i n a s s e m b la g e s from above 750 me t e r s a ro u n d S o u th G e o r g ia . U chio a l s o c o n s id e r e d A. e a r - l a n d i c h a r a c t e r i s t i c o f u p p e r b a t h y a l a s s e m b la g e s . In a d d i t i o n , U c h io c o n s i d e r e d E p o n id e s w e d d e l i e n s is (= E ilo h e d r a w e d d e l l e n s i s ) c h a r a c t e r i s t i c o f a s s e m b la g e s d e e p e r th a n 850 m e t e r s , w h i l e i t i s c h a r a c t e r i s t i c o f sa m p le s b elow 1500 m e te r s on t h e S o u th G e o rg ia s l o p e . B o th U chio and S a id o v a fo u n d B u lim ln a a c u l e a t a m ore c h a r a c t e r i s t i c o f d e p th s g r e a t e r th a n 850 o r 1000 m e t e r s , and th u s d e e p e r th a n th e g r e a t e s t f r e q u e n c i e s o f t h i s s p e c i e s r e c o r d e d h e r e . The z o n a t lo n o f n o n - c a l c a r e o u s f o r a m l n i f e r a p ro p o s e d h e r e i s v e r y s i m i l a r t o t h a t p r o p o s e d b y K e n n e tt ( i n p r e s s ) f o r th e R o ss S e a . B e ca u se o f a s h a llo w d e p th o f c a r b o n a te Figure 31 C om parison o f D epth Z o n a tlo n s i n t h e A n t a r c t i c . H o r i z o n t a l l i n e s a r e f a u n a l b o u n d a r i e s , h a tc h e d a re a B r e p r e s e n t t r a n s i t i o n a l b o u n d a r i e s , and d o u b le - e n d e d a rro w s i n d i c a t e sam p led d e p th s c o n s t i t u t i n g a f a u n a l zone s e p a r a t e d b y d e p th s w i t h o u t s a m p le s . 139 THIS STUDY CALCAREOUS S . ORKNEY »• S. SAND. NON CALC. 0ANOY ft ECHOLS 1966 BLANC - VERNET I9 6 S KENNETT fin p r in ) s a io o v a Mc k n ig h t 1961 1962 UCHIO I 9 6 0 SCHEDRINA 1958 (1964) S. GEORGIA UPPER SLOPE IO O O - LOWER < o SLOPE 2000 U 3 0 0 0 o 4 0 0 0 o 5 0 0 0 l4l c o m p e n sa tio n i n th e R oss Sea— o n ly 500 m e te r s — th e d e e p e r f a u n a l b o u n d a rie s i n K e n n e t t 's z o n a tio n a re b a se d on non- t r c a l c a r e o u s f o r a m i n if e r a a l s o . K e n n e tt re c o g n iz e d bound a r i e s a t 1300 and 2200 m e te rs w hich c o rre sp o n d to bound a r i e s i n th e S c o t ia and W eddell S eas a t 1200 to 1300 m e te rs and 2100 to 23OO m e te r s . F u rth e rm o re , C rib ro sto m o id e s su b - g lo b o su B , Ammomarglnullna e n s i s , M iliam mina a re n a c e a , and Reophax s u b f u s if o r m ls t y p i f y th e same d e p th zones i n th e Ross Sea a s i n th e S c o t ia and W eddell S e a s. W ater M asses and B e n th o n ic F o r a m ln if e r a l A ssem blages U chio (1960b) a s s o c i a t e d b e n th o n ic f o r a m l n i f e r a l a s - ' sem blag es w ith th e s t r a t i f i e d A n t a r c t ic W ater m asses i n th e f o llo w in g m anner: A ssem blage 1 2 3 C irc u m p o la r w a te r i s synonymous w ith th e Warm Deep L a y e r. The c o n t r a s t i n g z o n a tlo n s o f c a lc a r e o u s f o r a m in if e r a on th e S o u th G e o rg ia slopeB and on th e s lo p e s o f th e s o u th e rn and e a s t e r n S c o t ia R idge a r e a s s o c i a t e d w ith c o n tr a s t in g w a te r m asses in a way t h a t may B upport U c h io 's h y p o th e s is . D epth (m) W ater M asses ocn Qcn s u r f a c e w a te r and Circum - 350-b50 polar> w atep 850-2000 lo w er C ircu m p o lar w a te r > 2 0 0 0 b o tto m w a te r W ater m asses a re re c o g n iz e d by c h a r a c t e r i s t i c tem p era t u r e s and s a l i n i t i e s a s e s t a b l i s h e d by T-S c u rv e s ( c f . S v e rd ru p , Jo h n so n , and F lem ing, 1 9 4 2 ). Com parison o f p o te n t i a l te m p e ra tu re and s a l i n i t y r e l a t i o n s h i p s o f w a te r imme d i a t e l y so u th o f th e A n t a r c t i c C onvergence to w a te r i n th e n o r th e r n W eddell Sea (F ig u r e 3 2) e m p h asizes th e d i f f e r e n c e s betw een th e two a r e a s . The Warm Deep L ayer on th e u p p e r s lo p e s o u th o f S outh G e o rg ia h a s p r o p e r t i e s s i m i l a r to th o se found i n t h i s w a te r maBs j u s t s o u th o f th e A n ta r c tic C onvergence. Along th e s o u th e rn and e a s t e r n S c o t i a R idge, th e w a te r a t s i m i l a r l e v e l s i s f a r d i f f e r e n t , h a v in g been m o d ifie d by m ixing w ith A n t a r c t i c B ottom W ater and W eddell Sea s h e l f w a te r . F ig u re 9 shows t h a t a te m p e r a tu re maximum, i n th e u p p e r p a r t o f th e l a y e r and a s a l i n i t y maximum in t h e lo w er p a r t may be i d e n t i f i e d i n b o th a r e a s . However, th e maximum te m p e ra tu re i s a b o u t 1.6°C warmer s o u th o f South G e o rg ia th a n a lo n g th e s o u th e rn S c o tia R id g e , and th e s a l i n i t y maximum so u th o f S outh G e o rg ia l i e s a t 1400 to 1500 m e te rs w h ile i t i s a t o n ly 600 m e te rs i n th e n o r th e rn W eddell Sea. By e x t r a p o l a t i o n from th e n e a r e s t com plete deep h y d ro g ra p h ic s t a t i o n , th e w a te r a t 2000 m e te rs so u th o f S outh G eo rg ia h a s B a l i n l t y and p o t e n t i a l te m p e ra tu re c h a r a c t e r i s t i c s s i m i l a r to w a te r a t 1000 m e te rs i n th e Wed d e l l Sea (F ig u re 3 2 ). I f w a te r mass i s an Im p o rta n t f a c t o r a f f e c t i n g th e d i s t r i b u t i o n o f b e n th o n ic f o r a m i n if e r a , th e n asse m b la g es Figure 32 S a l i n i t y - P o t e n t i a l T em p e ra tu re C u rv e s S o u th o f S o u th G e o rg ia Compared w ith C u rv e s N ear th e A n t a r c t i c C onvergence and i n th e W ed d e ll Sea 1U3 ) •34.50 2 .5 - 34.55 S A L IN IT Y 34.60 _L 2.0 - 1 .5 - o o U Q C 3 £ 1 .0 - u CL S u H - < 0.5- z m t- o 0. o.oH - 0 . 5 - —1 .0— 34.65 ± 34.70 I 144 3 4 .7 5 1 HYDRO 177 575 SALINITY -POTENTIAL TEMPERATURE ENVELOPES A. NEAR ANTARCTIC CONVERGENCE Hydro Stations 094 096 164 169 B. NORTHERN WEOOELL SEA Hydro Stations 138 140 141 265 266 267 275 2000 3000 2000 3000 r4000 Numbers are depths in meters FIGURE 32 s o u th o f S o u th G e o rg ia s h o u ld d i f f e r fro m th o s e a lo n g th e s o u th e r n and e a s t e r n S c o t i a R idge* w h ile th o s e f e a t u r e s o f b a t h y a l f o r a m l n i f e r a l a s s e m b la g e s s h a r e d by t h e n o r t h e r n and s o u th e r n lim b s o f th e r i d g e s h o u ld o c c u r d e e p e r i n t h e n o r t h . C a lc a re o u s b e n th o n ic a s s e m b la g e s show e x a c t l y t h i s r e l a t i o n s h i p . The f i v e s p e c i e s c h a r a c t e r i s t i c o f t h e u p p e r b a t h y a l f a u n a l zone o f th e S o u th G e o rg ia s lo p e a r e n o t s i g n i f i c a n t s p e c i e s on th e s o u t h e r n and e a s t e r n s l o p e s o f th e r i d g e . On t h e o t h e r hand* E l l o h e d r a w e d d e l l e n s i s . a c h a r a c t e r i s t i c u p p e r b a t h y a l s p e c i e s on t h e s o u th e r n and e a s t e r n s l o p e s , i s a b u n d an t o n ly i n th e lo w e r b a t h y a l and a b y s s a l z o n es o f S o u th G e o rg ia . The u p p e r b a t h y a l zone o f S o u th G e o rg ia i s a s s o c i a t e d w ith t h e t e m p e r a t u r e maximum s t r a t u m o f th e Warm Deep L a y e r w h ich i s n o t w e l l d e f i n e d on th e s o u th e r n and e a s t e r n s l o p e s o f th e r i d g e . A b y s sa l and T re n c h B io to p e s F o u r b i o t o p e s a r e r e c o g n iz e d on t h e a b y s s a l b a s i n f l o o r s , and a f i f t h one i n th e S o u th S andw ich T re n c h , a l l o f w hich a re d o m in a ted by n o n - c a l c a r e o u s f o r a m i n i f e r a . A s i x t h b i o to p e o f c a l c a r e o u s f o r a m i n i f e r a o c c u r s i n t h e n o r t h e r n S c o t i a S e a , th e a s s e m b la g e s o f w h ic h b e a r much i n common w ith t h e .p r o b a b l y r e l i c t c a l c a r e o u s a s s e m b la g e s o f th e n o r t h e r n W ed d ell S e a . E ach b i o t o p e i s a g e o g ra p h ic a r e a c o n t a i n i n g r e l a t i v e l y hom ogeneous b e n th o n i c f o r a m i n i f e r a ! a s s e m b la g e s . In p r a c t i c e t h e b i o t o p e s a r e d e f i n e d by 146 c h a r a c t e r i s t i c a s s o c i a t i o n s o f a b u n d an t s p e c ie s w hich cumu l a t i v e l y t o t a l a l a r g e p a r t o f a l l th e f o r a m i n if e r a found t h e r e . S p e c i a l c o n s i d e r a t i o n was g iv e n th o s e s p e c ie s w hich a r e r e s t r i c t e d to c e r t a i n b i o t o p e s . N o n -c a lc a re o u s A b y ssa l B io to p e s D e s c r i p t i o n o f B io to p e s E le v e n B p e c ie s c o n s i s t e n t l y do m inate a sse m b la g e s i n th e f o u r n o n - c a lc a r e o u s a b y s s a l b i o t o p e s . T h e ir r e l a t i v e fre q u e n c y d i s t r i b u t i o n i n p e r c e n t o f th e t o t a l b e n th o n ic fa u n a i s shown i n F ig u re 33* 33A-L and th e b io to p e s t h e i r d i s t r i b u t i o n s h e lp to d e f i n e a r e p l o t t e d i n F ig u re 34. T ab le 4 l i s t s s i g n i f i c a n t f a u n a l and e n v iro n m e n ta l param e t e r s f o r e a c h o f th e b i o t o p e s . The a b y s s a l s lo p e s o f th e S c o t ia R idge have n o t been in c lu d e d i n t h e above b i o to p e s b e c a u se to do so w ould r e q u i r e b r o a d e n in g th e d e f i n i t i o n s to i n c lu d e e i t h e r lo w er f r e q u e n c i e s o f d i a g n o s t i c s p e c i e s o r o t h e r a s s o c i a t i o n s o f s p e c i e s . I n g e n e r a l , th e a sse m b la g e s from th e a b y s s a l s lo p e s a r e more s i m i l a r to th o s e on th e a d ja c e n t b a s in f l o o r s th a n to one a n o th e r ; th u s th e y do n o t th e m s e lv e s d e f i n e a s i n g l e b i o t o p e . U n d o u b ted ly a d d i t i o n a l sam ples i n th e a r e a s o f th e a b y s s a l s lo p e s w ould r e s u l t i n th e r e c o g n i t i o n o f s e v e r a l g e o g ra p h ic f a u n a l u n i t s t h e r e . Figure 33A-L R e l a t i v e F r e q u e n c ie s o f D om inant T ren ch and A b y ssa l N o n - c a lc a r e o u s S p e c ie s 33A R e l a t i v e F re q u e n c y o f M a r t i n o t t i e 1 1 a a n t a r c t i c a 147 148 SO * BATHYMETRY IN METERS S O * 6 6 * SS* SOUTH SANDWICH 29 ISLANDS & \ SOUTH ORKNEYS ( toot «• X= < I Percent P = Present 4 N r A R C T IC PERCENT MARTINOTTIELL A ANTARCTICA FIGURE 3 3 A Figure 33B R e l a t i v e F re q u e n c y o f E g g e r e l l a p a r k e r a e v a r . B 149 150 40* * * • » BATHYMETRY IN METERS SOUTH SANDWICH ISLANDS 22. L I* \ SOUTH ORKNEYS \ •0 * •0 * .tooo- to< X* <1 PERCENT M » r * * C T f C w * PERCENT E66ERELLA PARKERAE VAR. B FIGURE 33B Figure 33C R e la ti v e F requency o f C rib ro s to m o id e s u m b ilio a tu lu s s o l d a n i i 151 152 40* BATHYMETRY IN METERS * 0 1 65* X=<1 PERCENT - A N T A R C T IC ---------------------— C IR C L C 40* 50* PERCENT CRIBROSTOMOIDES UMBILICATULUS SOLDANII FIGURE 33C F ig u r e 33D R e l a t i v e F re q u en c y o f Reophax sp . A. 153 154 4 0 * BATHYMETRY IN METERS so* GEORGIA SOUTH SANDWICH ISLANDS SOUTH ORKNEYS ( * 0 * X =<l PERCENT P = PRESENT ANTARCTIC PERCENT REOPHAX SP. A FIGURE 33D Figure 33E R e la ti v e F req u en cy o f Cyolammina p u s i l l a 155 156 ♦ 0 * BATHYMETRY IN METERS s o * tono SOUTH SANDWICH ISLANDS \ SOUTH ORKNEYS ( 4000 60* ’2 000 * ' 55 4000 2000* 64 P=PRESENT AHrtncric 40* PERCENT CYCLAMMINA PUSILLA FIGURE 33E Figure 33F R e l a t i v e F re q u e n c y o f C r ib r o s to m o id e s s u b g lo b o s u s 157 158 so* BATHYMETRY IN METERS so* .3 0 0 0' SOUTH GEOROH •000 SOUTH SANDWICH ISLANDS ---- V I* \ SOUTH ORKNEYS ( 60* •0 * ■ i< 55o .2 0 0 0 - 52 X=<l PERCENT P= PRESENT A M T A H C T iC 40* JO* PERCENT CRIBROSTOMOIDES SUBGLOBOSUS FIGURE 33F Figure 33G R e l a t i v e F re q u e n c y o f G lom oB P ira c h a r o id e B 159 .40* B O * BATHYMETRY IN METERS 50* 4000 X= < l P E R C E N T 4 N T 4 ffC T IC 50* PERCENT GLOMOSPIRA CHAROIDES FIGURE 33G F ig u re 33H R e l a t i v e F re q u en c y o f A derco try m a glom eratum 161 162 SO* SO * •0 0 0 SOUTH SANOWICH ISLANDS - «7 S v SOUTH ORKNEYS \ }000* X = < l PERCENT P = PRESENT 16 J O ANTARCTIC 40* PERCENT ADERCOTRYMA GLOMERATUM FIGURE 33 H Figure 33I R e l a t i v e F re q u e n c y o f T r i t a x i s I n h a e r e n s 163 164 BATHYMETRY IN METERS l o U T H ^ GEORQU SOUTH SANDWICH ISLANDS V* \ SOOTH ORKNEYS I 60* 20< X =<1PERCENT P= PRESENT A N T A R C T IC 40* TRITAXIS INHAERENS PERCENT FIGURE 331 •Figure 33J R e l a t i v e F re q u e n c y o f P o rta tro c h a m m in a e l t a n i n a e 165 166 BATHYMETRY IN METERS • o o o SOUTH SANDWICH ISLANDS - *5 ' 4000 X = <l PERCENT P= PRESENT - A H T tR C T IC ----------- — C /R C lf — — 40* JO' PERCENT PORTATROCHAMMINA ELTANINI FIGURE 33 J Figure 33K R e la ti v e F req u en cy o f Conotrocham m ina k e n n e t t i 168 so* S O * W BATHYMETRY IN METERS so* GEOROW X=<lPERCENT P S PRESENT • MTtncne 40 * SO* PERCENT CONOTROCHAMMINA KENNETT FIGURE33K Figure 33L R e l a t i v e F re q u e n c y o f C r i tr o s to m o l d e s s p h a e r i l o c u i u s 169 170 BATHVMETRY IN METERS 8 0 * 8 0 * •ono SOUTH SANDWICH ISLANDS .4 0 0 0 ' SOUTH ORKNEYS 4000 '101 6 8 * X=<1PERCENT P= PRESENT ANTARCTIC 3 0 « CRIBROSTOMO IDES SPHAERILOCULUS PERCENT FIGURE 33 L 9 F ig u re 3^- A b y ssa l and H adal B io to p e s 171 172 so* 40* BATHYMETRY IN METERS 3 0 * SOUTH OEOROIff • 0 0 0 SOUTH SCOTIA SEA SANOWICH ISLANDS 60* -2 0 0 0 ' SOUTH ORKNEYS m .too* ABYSSAL AND HADAL BIOTOPES FIGURE 3 4 TABIE 4 S U M M A S Y OF IEESC5 A N D ABYSSAL BICTOPES E ast S co tia Basin P erip h e ra l Weddell Sea C en tral Weddell Sea Trench Bim Trench Depth 2 1+ 9C-3V70 m eters 3240-4200 m eters 37h0-h790 m eters 3980-4650 m eters 5420-6170 m eters 7000 m eters Dominant Species M a rtln o ttle lla a n ta rc tic a E ggerella parkerae v a r. B Crlbrostom oides um b lllcatu lu s so ld a n ll Beopbax sp . A Cyclammlna n u s llla Crlbrostom oides subglobosus Glomosplra charoides Adercotiyma glomeratum T rlta x is Inhaerens Portatrochammlna e lta n ln i Conotrochammina k e n n e ttl C rlbrostom oides sp h aerllo c u lu s Bare o r Absent Species Cyclammlna p u s I lia M a rtln o ttle lla a n ta rc tic a E g g erella parkerae v a r '. B C rlbrostom oides um b lllcatu lu s so ld a n ll M a rtln o ttle lla . a n ta rc tic a E g g erella parkerae v a r. B C rlbrostom oides u m b lllcatu lu s s o ld a n ll Cyclammlna pus111a E g g erella parkerae v a r. B C rlbrostom oides um b lllcatu lu s so ld a n ll C yclam ina p u s llla Dominants o f a l l o th e r bio to p es except Reophax sp . A Benthonlc Foram lnlfera JJo./gm. 1 0 . 5 -1 6 6 3.07-29.5 le s s than 13 1*0.0-91.1 51-119 0 Simpson’s D iv e rsity Index 7.56-26.3 2 . 36- 12 .4 8 3.36-8.65 11.70-14.1*9 3-13-4.61 Diatoms abundant ra re o r absent ra re o r absent abundant abundant Sediment Types diatom ooze clayey s i l t sand s i l t clay s i l t y clay clay clay sand s l i t clay sand ■ s i l t y clay sand s i l t c la y M -'J U) 174 E a s t S c o t i a B a s in B io to p e ( l 4 s a m p le s ) . — The E a s t S c o t i a B aB ln B io to p e o c c u r s a t s h a llo w e r d e p th s (2490 -3470 m) th a n t h e o t h e r a b y s s a l b i o t o p e s . S ed im en t ty p e s a r e d ia to m o o z e , d la to m a c e o u s c la y e y s i l t s , and d la to m a c e o u s sa n d s i l t c l a y s . M a r t l n o t t l e l l a a n t a r c t i c a ( F ig u r e 33A ), E g g e r e l l a p a r k e r a e v a r . B ( F ig u r e 33B ), and C r lb r o s to m o id e s u m b i l i c a - t u l u s s o l d a n l l ( F i g u r e 33C) t o g e t h e r c o m p rise from 14 t o 57 p e r c e n t o f t h e f o r a m i n i f e r a i n a l l o f th e t o t a l a s s e m b la g e s . A l l t h r e e s p e c i e s o c c u r w ith h i g h e s t r e l a t i v e f r e q u e n c i e s h e r e , an d E . p a r k e r a e v a r . B and C t. u m b i l i c a - t u l u s s o l d a n i i a r e r e s t r i c t e d to t h i s b i o to p e a n d a d j a c e n t s l o p e a s s e m b la g e s . R e l a t i v e f r e q u e n c i e s o f E. p a r k e r a e v a r . B a r e h i g h e s t i n sa m p le s o f d ia to m o o z e . The r e l a t i v e u n i f o r m i t y o f t h i s b i o t o p e i s shown by t h e f a c t t h a t o f t h e 84 s p e c i e s r e c o r d e d h e r e , 17 o c c u r i n 12 o r more s a m p le s . 1 T h ese 17 s p e c i e s i n c l u d e th e t h r e e d o m in an t s p e c i e s a n d A d e rc o try m a g lo m e ra tu m , C rlb r o s to m o id e s c o n t o r t u s , C.. s u b - g l o b o s u s . H a p lo p h ra g m o ld e s c a n a r i e n s l s , H. p a r k e r a e , Hormo- s i n a g lo b u l i f e r a , P o rta tro o h a m m in a e l t a n i n a e , Reophax s p . A, R . o v l c u l a , T e x t u l a r i a w l e s n e r i , T r i t a x i s i n h a e r e n s , T ro - cham m lna g r i s e a , T. i n c o n s p l c u a , and T. q u a d r l c a m e r a t a . P e r i p h e r a l W e d d e ll Sea B io to p e (9 s a m p le s ) . — The P e r i p h e r a l W ed d ell S ea B io to p e l i e s s o u th o f th e E a s t S c o t i a B a s i n B io to p e b e y o n d t h e S c o t i a R id g e . I t i s s l i g h t l y 175 d e e p e r (3 4 2 0 -4 2 0 0 m) an d s e d im e n ts a r e f i n e r b e in g s i l t y c l a y s and c l a y s . M ost s i g n i f i c a n t , p e r h a p s , diatom B a r e v e ry r a r e I n t h e s e d im e n ts p o s s i b l y I n d i c a t i n g lo w e r p r o d u c t i v i t y o f t h e o v e r l y i n g w a t e r s a n d c h e m ic a l d i f f e r e n c e s In th e I n t e r s t i t i a l w a t e r s su c h a s lo w e r c o n c e n t r a t i o n s o f d i s s o l v e d s i l i c a . T h is b i o t o p e i s n o t u n if o r m i n d e t a i l , i t s p r i n c i p a l u n i f y i n g f e a t u r e b e in g t h e dom inance o f on e s p e c i e s , Cyclam m lna p u s i l l a ( F i g u r e 3 3 E ), w h ic h c o m p ris e s from 10 to 64 p e r c e n t o f a l l a s s e m b la g e s an d i s fo u n d o n ly i n t h i s b i o t o p e an d on s l o p e s a d j a c e n t to t h i s b i o t o p e . Two .o th e r s p e c i e s , G lo m o sp ira c h a r o i d e s ( F ig u r e 33G) and C r i b r o s t o - m o ld es s u b g lo b o s u s ( F i g u r e 33F) s h a r e d dom inance i n some sa m p le s . Of a t o t a l o f 60 s p e c i e s r e c o r d e d from t h i s b i o t o p e , o n ly s i x o c c u r r e d i n se v e n o r more s a m p le s . T hese i n c l u d e th e t h r e e ab o v e an d A d e rc o try m a g lo m e ra tu m , Ammo- b a c u l l t e s f o l i a c e o u s f . r e c u r v a , an d Psam m osphaera f u s c a . C e n t r a l W ed d e ll S ea B io to p e (4 sa m p le s).— I n f o u r sam p les from th e c e n t r a l W ed d e ll S ea (a n d one sam ple w hich la c k e d s u r f a c e m a t e r i a l ) , £ . p u s i l l a was v e ry r a r e o r a b s e n t . In t h r e e o f t h e s e , s p a r s e f o r a m l n i f e r a l a s s e m b la g e s a r e dom i n a te d by C r lb r o s to m o id e s s u b g lo b o s u s ( F ig u r e 33F) w ith A d e rco try m a g lo m e ra tu m se c o n d i n I m p o r ta n c e . C r i b r o s t o - m o id es s p h a e r l l o c u l u s . A m m o b acu lites f o l i a c e o u s f . r e c u r v a . and P o rta tro o h a m m in a e l t a n l n a e a r e a l s o fo u n d i n a l l t h r e e 176 a s s e m b la g e s . Only a few f o r a m i n i f e r a l sp ecim en s w ere found i n th e f o u r t h sam ple and i n th e c o re w ith o u t s u r f a c e m a te r i a l . The C e n tr a l W eddell Sea B io to p e i s r e l a t e d fau n a l-ly and e n v ir o n m e n ta lly to th e P e r i p h e r a l W edd ell Sea B io to p e , th e o n ly im p o r ta n t d i f f e r e n c e b e in g th e a b se n c e o f Cyclam - m ina p u s i l l a i n th e fo rm er a lth o u g h sa m p le s o c c u r i n a d e p th ra n g e (3740-4790 m) o v e r la p p in g th e d e p th ra n g e o f t h i s s p e c i e s . As i n th e P e r i p h e r a l W ed d ell Sea B io to p e , se d im e n ts a r e c la y s w ith v e r y few d ia to m s . T ren ch Rim B io to p e (3 s a m p le s ) . — In ' t h r e e sam ples e a s t o f th e S o u th Sandwich T rench d ia to m s a r e a b u n d a n t i n th e ' se d im e n ts a s th e y a r e i n th e E a s t S c o t i a B a s in B io to p e . T here i s , how ever, a 500 m e te r d i f f e r e n c e b etw een th e s h a l lo w e s t o f th e s e sam ples and th e d e e p e s t o f th e E a s t S c o t ia B a sin B io to p e . I t s d e p th ra n g e (3980-4650 m) i s more s im i l a r to t h a t o f th e C e n tr a l W eddell Sea B io to p e . U n lik e th e o t h e r t h r e e a b y s s a l b i o t o p e s , much o f th e s i l t and san d c o n s i s t s o f a n g u la r , v e s i c u l a r v o lc a n ic d e b r i s w hich c o u ld f a v o r some a g g l u t i n a t e d s p e c i e s c a p a b le o f u s in g t h i s m a te r i a l i n th e c o n s t r u c t i o n o f t h e i r t e s t s o v e r o t h e r s t h a t f i n d such m a t e r i a l l e s s d e s i r a b l e . S ed im en t t e x t u r e s a re sa n d , s i l t , and c la y . A lth o u g h th e s e t h r e e sam p les a r e s e p a r a t e d from one a n o th e r by 5° o f l a t i t u d e , th e y have re m a rk a b ly s i m i l a r 177 f o r a m i n i f e r a l a s s e m b la g e s . The u n i f o r m i t y o f t h i s b io to p e i s shown b y th e f a c t t h a t 23 s p e c i e s a r e common to a l l t h r e e sa m p le s. The do m in an t s p e c i e s , GlomoBPira c h a ro id e s ( F ig u r e 33G ), T r l t a x i s I n h a e r e n s (F ig u r e 3 3 1 ) and A derco try m a g lo m eratu m ( F ig u r e 33H), t o g e t h e r co m p rise 37* 44, and 52 p e r c e n t o f th e f o r a m i n i f e r a i n th e t h r e e a sse m b la g e s. S i g n i f i c a n c e o f E n v ir o n m e n ta lly R e s t r i c t e d S p e c ie s E ach n o n - c a lc a r e o u s a b y s s a l b io to p e h a s a r e l a t i v e l y u n if o r m e n v iro n m e n t w hich d i f f e r s from t h a t o f th e o t h e r b i o t o p e s . E n v iro n m e n ta l f a c t o r s w hich d i f f e r betw een b i o to p e s a r e d ia to m c o n te n t o f th e s e d im e n ts , c h a r a c t e r o f th e s e d im e n t p a r t i c l e s ( v o lc a n ic o r t e r r i g e n o u s ) , se d im e n t t e x t u r e , and d e p th . U n d o u b te d ly t h e r e a r e o t h e r f a c t o r s , n o t c o n s id e r e d i n t h i s i n v e s t i g a t i o n , w hich a r e e q u a l ly o r more i m p o r t a n t i n I n f l u e n c i n g t h e d i s t r i b u t i o n s o f a b y s s a l s p e c i e s . N e v e r t h e l e s s , th e s e t h r e e f a c t o r s , o p e r a t in g in one o r more w ays, a p p e a r to have an im p o r ta n t r o l e . Four o f th e e le v e n a b u n d a n t a b y s s a l s p e c i e s have r e s t r i c t e d g e o g r a p h i c r a n g e s c l e a r l y i l l u s t r a t i n g th e e f f e c t o f th e s e en v ir o n m e n ta l f a c t o r s . M a r t l n o t t l e l l a a n t a r c t i c a o c c u r s i n e v e ry sam ple o f d la to m a c e o u s se d im e n t belo w 2000 m e te rs e x c e p t f o r th o s e fro m th e S o u th Sandw ich T rench below 5000 m e te r s , two B ta- f 178 t l o n s from th e n o r t h e r n p a r t o f th e a r e a d o m in a te d by c a l c a re o u s f o r a m i n i f e r a , a n d two o t h e r s on th e s o u th e r n S c o t ia R idge (F ig u r e 33A ). O th e r t h a n a few sp e c im e n s a t a s i n g l e s t a t i o n (USC 1 0 6 2 ), i t d id n o t o c c u r i n n o n -d iato m aceo u B s e d im e n ts . E g g e r e lla p a r k e r a e v a r . B i s se co n d o n ly to M. a n t a r c t i c a i n c h a r a c t e r i z i n g d la to m a c e o u s a b y s s a l s e d im e n ts . A l th o u g h i t was a b s e n t i n a l l sa m p le s d o m in a ted b y c a l c a r e o u s f o r a m i n i f e r a , i t o c c u r s i n a l l o t h e r sam p les o f d la to m a c e o u s B edim ents b etw een -2000 m e te r s an d 3500 m e te rs e x c e p t one o f t h o s e from th e s o u th e r n S c o t i a R id g e w hich alB o l a c k s M. a n t a r c t i c a (F ig u r e 33B) , I t d o e s n o t o c c u r i n n o n -d ia to m a c - eo u s s e d im e n ts . T h is s p e c i e s d o e s n o t a p p e a r to t o l e r a t e g r e a t e r d e p th s ( F ig u r e 2 9 ) w h ic h may e x p la in i t s a b se n c e from th e T rench Rim B io to p e . C rlb ro s to m o id e s u m b l l l c a t u l u s s o l d a n i i i s r e s t r i c t e d to d lato m a c e o u s s e d im e n ts a lm o s t a s c o m p le te ly a s th e f o r mer tw o. A se co n d f a c t o r , h o w e v e r, seems to l i m i t t h i s s p e c i e s ' d i s t r i b u t i o n a s i t was n o t fo u n d i n s e d im e n ts o f v o lc a n ic c o m p o s itio n e x c e p t f o r a few sp e c im e n s a t one s t a t i o n (USC 1 0 4 0 ). S in c e t h i s s p e c i e s c o n s t r u c t s i t s t e s t o f m in e r a l g r a i n s r e l a t i v e l y l a r g e com pared to i t s t o t a l s i z e , th e a n g u la r v e s i c u l a r v o l c a n i c p a r t i c l e s a r e p o s s i b l y u n a c c e p ta b le b u i l d i n g m a t e r i a l s . Cyclammlna p u s i l l a , i n c o n t r a s t to th e abov e t h r e e s p e c i e s , i s e x c e e d in g ly a b u n d a n t i n some s e d im e n ts w ith 179 fe w o r no d ia to m s , a n d t o t a l l y a b s e n t i n sa m p le s w ith a b u n d a n t d ia to m s . I t d id n o t o c c u r f a r fro m th e s l o p e s o f t h e A n t a r c t i c P e n i n s u l a an d t h e S c o t i a R id g e , h o w ev er, b e in g a b s e n t i n th o s e sa m p le s fro m th e c e n t r a l an d e a s t e r n W e d d e ll S e a a lth o u g h s e d im e n t ty p e and d e p th a p p e a r, f a v o r a b l e . E a rla rid (1933* 193^* 193^) r e c o r d e d 40 o c c u r r e n c e s o f M. a n t a r c t i c a ( a s C l a v u l i n a communis d 'O rb ig n y ) and 23 o c c u r r e n c e s o f Cyclam m ina p u s i l l a from 10°W to 90°W i n th e A n t a r c t i c O cean. H is r e c o r d s c o n firm th e d i s t r i b u t i o n s o f t h e s e s p e c i e s i n th e S c o t i a and n o r t h e r n W ed d ell S e a s a s d e te r m in e d by t h e a u th o r an d p r o v id e a d d i t i o n a l o c c u r r e n c e s o f th e s p e c i e s s o u t h , e a s t , and w e s t o f th e b o r d e r s o f t h i s s t u d y ( F ig u r e 3 5 ) , He n o te d th e a b u n d an ce o f d ia to m s i n sa m p le s from w h ich h e o b t a i n e d f o r a m i n i f e r a , a n d , i n a d d i t i o n , t h e s e d im e n ts o f t h e same sa m p le s s t u d i e d by E a r la n d (1 9 3 6 ) w ere d e s c r i b e d by P i r i e ( 1 9 1 3) who e s t im a t e d th e a b u n d a n c e o f d ia to m s i n e a c h sa m p le . As E a r la n d d i d n o t d e s c r i b e Trocham m lna s o l d a n i ( =C rlb r o s to m o id e s u m b i l i c a t u l u s s o l d a n l l ) u n t i l h i s l a s t r e p o r t n o r r e c o g n iz e E . p a r k e r a e v a r . B a s d i s t i n c t fro m E g g e r e l l a b r a d y i , h i s r e c o r d s c a n n o t be u s e d to s tu d y f u r t h e r th e d i s t r i b u t i o n s o f t h e s e two s p e c i e s . F ig u r e 35 show s t h a t M. a n t a r c t i c a and C., p u s i l l a a r e a s s o c i a t e d a ro u n d t h e p e r i m e t e r o f th e A n t a r c t i c c o n t i n e n t b u t o c c u r s e p a r a t e l y i n t h e g r e a t e r p a r t o f th e S c o t i a an d W e d d e ll S e a s . £ . p u B l l l a o c c u r s a lo n g th e s o u t h e r n , w e s te r n Figure 35 D i s t r i b u t i o n s o f M a r t i n o t t i e 1 1 a a n t a r c t i c a and Cyclam m lna p u s i l l a from lO^W. to 90°W i n t h e A n t a r c t i c Ocean 180 181 90*W K m 900 8 0 * MARTINOTTIELLA ANTARCTIA 70* CYCLAMMINA PUSILLA 90* ‘ZOOOI • • •0* 7 0 * 6 9 * 60* FIGURE 35 182 an d n o r t h e r n m a rg in s , b u t n o t In th e I n t e r i o r o f th e Wed d e l l S e a . Those sam ples c o n ta in in g b o th s p e c i e s a p p e a r to have a t l e a s t two f a c t o r s I n common: p r o x im ity to la n d and a m o d era te q u a n t i t y o f d ia to m s . For ex am ple, d iato m s a r e 1 and 2 p e r c e n t o f th e t o t a l Bedim ent ( P i r i e , 1913) I n th o s e sam p les from th e s o u th e a s te r n W eddell Sea (WS 406 , 417, 4 l8 ) i n w hich b o th s p e c i e s o c c u r . T hese p e r c e n ta g e s o f d ia to m s a r e h i g h e r th a n f o r m ost o t h e r W eddell Sea s e d i m e n ts. F u r t h e r , E a r la n d n o te s d iato m s In one o f th e t h r e e sampl€S*- w e st o f th e A n t a r c t i c P e n in s u la w hich a ls o c o n t a i n e d b o th s p e c i e s (WS 4-95* 502, 517) • M. a n t a r c t i c a - was p o s s i b l y s i l i c e o u s cem ent, d is c u s s e d l a t e r , and t h e r e f o r e may r e q u i r e h ig h c o n c e n tr a ti o n s o f d i s s o l v e d s i l i c a i n f e r r e d to p r e v a i l i n d la to m a c e o u s s e d im e n ts . The i n h i b i t o r y e f f e c t o f an abundance o f d ia to m f r u s t u l e s upon C _ , p u s i l l a i s p r o b l e m a t i c a l . ' T rench B io to p e (4 sam p les) T hree sa m p le s from th e u p p e r le v e lB o f t h e S o uth Sand w ich T ren ch (5420-6170 m) c o n ta in u n iq u e f o r a m i n i f e r a l a s se m b la g e s . A number o f s p e c i e s w hich o c c u r p e r s i s t e n t l y b o th on th e w e st s lo p e o f th e tr e n c h and on th e e a s t e r n t r e n c h rim a r e a b s e n t w ith in th e tr e n c h j and a few s p e c i e s w hich o c c u r e ls e w h e re re a c h v e ry h ig h f r e q u e n c i e s t h e r e . In u p p e r t r e n c h sa m p le s, f o r a m i n i f e r a l num bers a re a s h ig h 183 a s th o s e In th e T ren ch Rim and S c o t i a Sea B io to p e s , b u t th e d e e p e s t tr e n c h Bample (7690 m) i s b a r r e n o f f o r a m i n if e r a (T ab le 4 ) . D i v e r s i t y i s v e ry low. In T able 2 , r e l a t i v e f r e q u e n c i e s o f s p e c i e s i n th e S o u th Sandw ich T rench B io to p e may be com pared w ith th o s e on th e s lo p e o f th e S o u th Sandw ich Arc and w ith th o s e o f th e T rench Rim B io to p e . P o rta tro c h a m m ln a e l t a n i n a e (F ig u re 33J) c o m p rise s more th a n 30 p e r c e n t o f th e f o r a m i n i f e r a i n a l l t h r e e tr e n c h sam ples t h a t c o n ta in f o r a m i n i f e r a , and Cono trocham m ina k e n n e t t i ( F ig u r e 33K) c o m p rise s more th a n 20 p e r c e n t o f th e f o r a m i n i f e r a i n two o f them . E x c e p t i n th e t r e n c h , th e s e two s p e c i e s have v e ry d i f f e r e n t d i s t r i b u t i o n s . P. e l t a n i n l o c c u r s i n a lm o s t e v e ry sam ple below 490 m e te rs , th e o n ly u n u s u a l f e a t u r e a b o u t i t s o c c u rr e n c e i n th e tr e n c h b e in g i t s c o n s i s t e n t l y h ig h r e l a t i v e f r e q u e n c i e s . In con t r a s t , £ . k e n n e t t i o c c u r s no s h a llo w e r th a n 2720 m e te rs , and i s an I n c o n s i s t e n t l y o c c u r r in g s p e c i e s e v ery w h ere e x c e p t I n th e tr e n c h . I t s d i s t r i b u t i o n i n t h i s s tu d y s u g g e s ts t h a t i t c o u ld be an endem ic t r e n c h s p e c i e s t h a t h a s In v ad e d th e n e ig h b o rin g a b y s s a l e n v iro n m e n t. T here i s no o t h e r e v id e n c e o f endemism i n th e t r e n c h f o r a m i n i f e r a l f a u n a . The u n iq u e n e s s o f t h e t r e n c h a sse m b la g e s i s Bhown j u s t a s c l e a r l y by th e s p e c i e s w hich do n o t o c c u r t h e r e . Two s p e c i e s w hich a r e a b u n d a n t and p e r s i s t e n t i n th e a b y s s a l sam ples on b o th s i d e s o f th e tr e n c h a r e O lo m o sp ira c h a ro id e s (5 to 25 p e r c e n t ) and T r l t a x i s I n h a e r e n s (8 to 18 p e r c e n t ) . 184 E x c e p t f o r a s i n g l e specim en o f G. c h a r o i d e s , th e y a r e b o th a b s e n t from th e t r e n c h . M a r t l n o t t l e l l a a n t a r c t i c a a n d H&R- lo p h ra g m o id e s p a r k e r a e , w hich a re p r e s e n t i n a l l a b y B sa l sa m p le s im m e d ia te ly a ro u n d t h e t r e n c h th o u g h n o t a s a b u n d a n t l y a s th e fo rm er two s p e c i e s , a r e a l s o a b s e n t from th e t r e n c h . A n o th e r u n u s u a l f e a t u r e i s th e a b s e n c e from any o f th e t r e n c h sam ples o f sp ecim en s l a r g e enough t o be r e t a i n e d on a 0 .5 mm s c r e e n . M oreover, no f o r a m i n i f e r a a r e p r e s e n t i n t r e n c h M enzies tr a w ls (USC 589* USC 6 3 6 , USC 6 3 7 ) ta k e n w ith a 0 .5 0 5 mm n e t . I n c o n t r a s t , t h r e e M enzies t r a w l s (USC 573* USC 6 0 3 , USC 6 0 6 ) from th e e a s t e r n rim o f t h e t r e n c h c o n ta in e d many f o r a m i n i f e r a . The s h a llo w e s t sam ple (5420 m) o f th e T ren ch B io to p e i s from below th e s i l l d e p th a s shown b y t h e f a c t t h a t th e 5000 m e te r c o n to u r c l o s e s a ro u n d th e t r e n c h w h e rea s th e 4000 m e te r c o n to u r d o es n o t ( F ig u r e 2) . I n s p e c t i o n o f h y d r o g r a p h ic d a ta from f o u r ELTANIN s t a t i o n s from th e t r e n c h r e v e a l s t h a t th e te m p e ra tu re r i s e s a d i a b a t i c a l l y d e e p e r th a n a b o u t 4500 m e te rs , and a t 6000 m e te r s i t i s a b o u t 0 .1 °C h i g h e r th a n th e minimum v a lu e r e c o r d e d i n t h e t r e n c h . O th e r h y d ro g ra p h ic p r o p e r t i e s , I n c l u d i n g o x y g e n , do n o t d i f f e r s i g n i f i c a n t l y from t h e i r v a lu e s a t s i l l d e p th . T ex - t u r a l l y two o f th e sam p les a re B l l t y c l a y s , b u t th e o t h e r two a r e sand* s i l t * c la y B , w hich a re s i m i l a r to t e x t u r e s on t h e B lope o f th e S outh Sandw ich Arc a n d on th e e a s t e r n rim 185 o f t h e t r e n c h . B oth d ia to m s and r a d i o l a r i a n s a r e a b u n d a n t i n t r e n c h s e d im e n ts . C om parison w ith F o r a m in i f e r a l F a u n a s from O th e r T re n c h e s F o r a m in i f e r a have been s t u d i e d from t h r e e o t h e r t r e n c h e s : Bandy and R o d o lfo (1964) s t u d i e d s i x t r a w l an d t h r e e c o r e sa m p le s from below 5500 m e te rs i n th e P e r u - C h ile T re n c h ; and S h c h e d rin a (1958) s t u d i e d th e K u ril-K a m c h a tk a T ren ch and d i s c u s s e d t h e f o r a m i n i f e r a l a sse m b la g e i n a sam ple from th e Ja p a n T ren ch (7230 m) r e p o r t e d on b y B rad y ( 1 8 8 4 ) . No f a u n a l p e c u l i a r i t i e s w ere r e c o r d e d i n t h e sam p l e s fro m th e P e r u - C h ile T ren ch o r th e J a p a n T re n c h to d i s t i n g u i s h them from n e a rb y a b y s s a l sa m p le s. I n t h e K u r i l - K am chatka T re n c h , h ow ever, a s s e m b la g e s from 4850 t o 5570 m e te r s w ere v e r y d i v e r s e , w h e rea s th o s e from 6000 to 7230 m e te r s c o n ta in e d f a r fe w e r s p e c i e s m ost o f w h ich a l s o o c c u r r e d a t l e s s e r d e p th s . A d i s t i n c t i v e fa u n a was fou n d from 8100 t o 9050 m e te r s i n w hich sev en s p e c i e s w ere th o u g h t to be new. S h c h e d rin a c o n c lu d e d , h ow ever, t h a t to o l i t t l e was known o f d e e p -w a te r f o r a m i n i f e r a to p r o p o s e t h a t t h e s e s p e c ie B a r e r e s t r i c t e d to such g r e a t d e p th s . L arg e s p e c i mens o f f o r a m i n i f e r a w ere s p e c i f i c a l l y n o te d i n t h e P e r u - C h ile and K u ril-K a m c h a tk a T re n c h e s . T hus, i n t h e u p p e r l e v e l s o f b o th t h e S o u th Sandw ich and K u ril-K a m c h a tk a T re n c h e s , th e fa u n a i s l a r g e l y a re d u c e d a b y s s a l f a u n a . 186 Prom th e a v a i l a b l e d a t a , th e S outh Sandwich T rench a p p e a rs u n iq u e I n th e a b se n c e o f l a r g e r f o r a m i n if e r a In I t s u p p e r l e v e l s and th e a b se n c e o f any f o r a m in if e r a I n one sam ple from i t s lo w e r l e v e l s . At th e p r e s e n t tim e , th e d e g re e o f endemism in tr e n c h f o r a m i n i f e r a l fa u n a s d o es n o t a p p e a r to a p p ro a c h t h a t found i n th e M etazo a. A cco rd in g to W olff ( i 9 60) , s p e c ie s a re endem ic to th e h a d a l zone ( > 6000 m ). A b y ssa l C a lc a re o u s A ssem blages I n c l u d i n g th e c a l c a r e o u s a sse m b la g es from th e n o r th e r n S c o t i a R id g e , th e p r o b a b le r e l i c t assem blages, i n th e n o r t h e r n W ed d ell S e a , and th e one s u b s u rf a c e c a lc a r e o u s assem b l a g e i n c o re USC 3 1 6, t h e r e a r e o n ly 12 a b y s s a l sam ples ( > 2000 m) [fro m th e a r e a ] i n w hich c a lc a r e o u s f o r a m i n if e r a c o n s t i t u t e d more th a n 30 p e r c e n t o f th e t o t a l b e n th o n ic s . A lth o u g h s p e c i e s v a ry g r e a t l y i n . r e l a t i v e fre q u e n c y from one c a l c a r e o u s a sse m b la g e to a n o th e r , most o f th e assem b l a g e s h a v e much i n common. F o r exam ple, E ilo h e d r a w e d d el- l e n s i s and E p is to m l n e l l a e x ig u a w ere found i n a l l o f them . These two s p e c i e s a r e c h a r a c t e r i s t i c o f a b y s s a l c a lc a r e o u s a s s e m b la g e s from o t h e r p a r t s o f th e A n t a r c t i c a s w e ll (U ch io , 1960b ; M cK night, 1962; Pflum , 1966) . N u t t a l l d e s u m b o n lfe ra o c c u r s i n a l l b u t two o f them. T h is s p e c ie s was r e p o r t e d from th e S c o t ia Sea a r e a by E a r la n d (193*0 and h a s a l s o b een r e p o r t e d from th e N o rth A t l a n t i c ( P h le g e r , 187 P a rk e r* and P i e r s o n , 1 9 5 3 ); h o w ev er I t h a s n o t b e en r e p o r t e d i n p r e v i o u s q u a n t i t a t i v e s t u d i e s i n t h e A n t a r c t i c . D om inant a b y s s a l c a l c a r e o u s s p e c i e s , f o llo w e d b y th e num ber o f sam p les i n w hich th e y c o n s t i t u t e d m ore th a n 10 p e r c e n t o f th e t o t a l a r e : E il o h e d r a w e d d e l l e n s is 9 C a s s i d u l i n a s u b g lo b o s a 1 N u t t a l l d e s u m b o n lfe ra 7 E p i s t o m i n e l l a ? a r c t i c a 1 E p i s t o m i n e l l a e x ig u a 5 O r i d o r s a l i s t e n e r a 1 N o n io n e lla i r i d e a 3 S t a i n f o r t h i a c o m p la n a ta 1 I s l a n d ! e l l a q u a d r a ta 2 A ssem b lages d o m in a te d b y N. u m b o n lf e r a a r e fo u n d o n ly a t a b y s s a l d e p th s (below 2000 m ), w h i l e E . w e d d e l l e n s i s , E . e x ig u a , and N. i r i d e a a r e i m p o r t a n t e le m e n ts i n th e b a t h y a l a s s e m b la g e s a s w e l l . A b u n d an t sp e c im e n s o f N. i r i d e a w ere n o te d i n t h e n o r t h e r n c a l c a r e o u s p r o v i n c e , b u t n o t i n W ed dell Sea s a m p le s . Some O b s e r v a tio n s on C a lc a r e o u s an d P o s s i b l y S i l i c e o u s A g g l u t i n a t e d F o r a m in i f e r a W h ile a n a ly z in g th e d i s t r i b u t i o n o f a g g l u t i n a t e d fo ram i n i f e r a , th e a u th o r n o te d c e r t a i n r e l a t i o n s h i p s b e tw ee n v a r i o u s p r o p e r t i e s o f th e t e s t w a l l o f a few d e e p - w a te r s p e c i e s an d t h e i r o c c u r r e n c e s . T hose s p e c i e s f o r w hich su ch a r e l a t i o n s h i p e x i s t s f a l l i n t o two c a t e g o r i e s , one w ith w h ite to g r e y c a l c a r e o u s w a l l s an d t h e o t h e r w i t h w h ite and p o s s i b l y s i l i c e o u s w a l l s . B o th k i n d s o f w a l l s a r e e a B lly 188 s e p a r a t e d from th e r e d d i s h brown ty p e t h a t i s more t y p i c a l o f a g g l u t i n a t e d f o r a m i n i f e r a . D i s t r i b u t i o n o f C a lc a r e o u s A g g lu tin a te d F o r a m in i f e r a When I t was d is c o v e r e d t h a t th e p l a n k t o n i c and th e h y a l i n e b e n th o n ic f o r a m i n i f e r a had a r e s t r i c t e d d i s t r i b u t i o n I n th e S c o t ia and W eddell S e a s and t h a t su c h d i s t r i b u t i o n s w ere p ro b a b ly r e l a t e d to th e a v a i l a b i l i t y o r s o l u t i o n o f c a lc iu m c a r b o n a te , o b s e r v a t i o n s w ere made to d e te r m in e th e o c c u r r e n c e o f c a l c i t e In a g g l u t i n a t e d s p e c i e s . A p p l i c a t i o n o f d i l u t e h y d r o c h lo r ic a c i d w ith a f i n e b r u s h r e v e a l e d t h a t th e t e s t s o f n in e a g g l u t i n a t e d s p e c i e s ( F ig u r e 3 6 ) o f t h e f a m ily A ta x o p h ra g m iid a e w ere s o l u b l e . Specim ens o f o t h e r s p e c i e s t e s t e d d id n o t r e a c t w ith a c i d e x c e p t f o r some w hich had i n c o r p o r a t e d c a l c a r e o u s f o r a m i n i f e r a i n t o t h e i r t e s t s . E le v e n M enzies t r a w l and P e t e r s e n g ra b sam p l e s w ere w ashed on a 0 .5 0 0 mm s c r e e n t o o b t a i n m ore s p e c i mens o f th e l a r g e r c a lc a r e o u s a g g l u t i n a t e d s p e c i e s . F o u r o f th e s e sam p les y i e l d e d a d d i t i o n a l s p e c im e n s , b u t i n o n ly two w ere th e y common (3 and 50 p e r c e n t o f th e f o r a m i n i f e r a r e t a i n e d on a 0 .5 0 0 mm s c r e e n ) . C a lc a re o u s a g g l u t i n a t e d s p e c i e s n e v e r form more th a n a s m a ll p e r c e n t o f th e t o t a l b e n th o n ic p o p u l a t i o n s i n c o r e s a n d g r a b s . One o r m ore, u s u a l l y tw o, o f t h e s e s p e c i e s w ere fo u n d a t a t o t a l o f 16 s t a t i o n s (a M enzies t r a w l w ith a t - Figure 36 O c c u rre n c e s o f Those A g g lu tin a te d F o r a m in if e r a W hich Have C a lc a re o u s Cement and Those Which Have P o s s i b l y S i l i c e o u s Cement Compared w ith th e P e r c e n ta g e s o f C a lc a re o u s F o ra m in if e ra i n T o ta l A ssem b lag es. 189 FIG U R E 36 100 CALCAREOUS '/ . BENTHONICS / y IN TOTAL / / POPULATION AGGLUTINATED WALL TYPES OCCURRENCES CALCAREOUS NON-CALCAREOUS • > 6 2 1 | ■ > 6 2 1 | O ) 500m q > 500t| V SAMPLES > 5 0 0 i| I TT i i i i i i i > i r m r i i i i i V V V V ATAXOPHRAGMII DAE DOROTHIA SP. • • • EGGERELLA NITENS < KARRERIELLA BRADYI K. CATENATA • K. OEFORMIS K. NOVANGLIAE O MARTINOTTIELLA MILLITTI O RUDIGAUDRYINA INEPTA • . E. PARKERAE VAR.A CALCAREA • • • • • • • • • • E. PARKERAE VAR. B SILICEA I M. ANTARCTICA D O B ■ I O • O I ■ ■■ RZEHAKINIDAE SPIROLOCAMMINA TENUIS M VD O ta c h e d c o re i s h e r e c o n s id e r e d one s t a t i o n ) . I n 15 o f th e s e 16 s t a t i o n s , c a l c a r e o u s b e n th o n i c s form more th a n 30 p e r c e n t o f th e t o t a l b e n th o n ic a s s e m b la g e s . F u rth e rm o re , i n a l l b u t one o f th e sa m p le s o f t h i s s tu d y from below 1500 m e te rs i n w hich c a l c a r e o u s f o r a m i n i f e r a w ere a b u n d a n t, c a l c a re o u s a g g l u t i n a t e d fo rm s w ere p r e s e n t . The d i s t r i b u t i o n a l p a t t e r n o f th e c a l c a r e o u s a g g l u t i n a t e d f o r a m i n i f e r a , l i k e t h a t o f th e h y a l i n e b e n th o n i c s and th e p l a n k t o n i c s , i s r e g a rd e d a s b e in g i n f l u e n c e d by th e r a t e o f s o l u t i o n o f c a l cium c a r b o n a te a t th e s u r f a c e o f t h e s e d im e n t. Wood (19^9) has. shown t h a t t h e c a l c i t e i n th e w a l l s o f some A ta x o p h ra g - m iid a e , a s w e ll a s o f some s p e c i e s o f o t h e r f a m i l i e s o f a g g l u t i n a t e d f o r a m i n i f e r a , i s p r o b a b ly s e c r e t e d . D i s t r i b u t i o n o f W h ite . P o s s i b l y S i l i c e o u s F o r a m in if e r a A b y s sa l s p e c i e s w ith w h ite p o s s i b l y s i l i c e o u s w a lls a r e M a r t i n o t t i e l l a a n t a r c t i c a , E g g e r e l l a p a r k e r a e v a r . B, and S p iro lo ca m m in a t e n u i s . B a th y a l s p e c i e s w hich a r e a ls o in c lu d e d h e r e a r e M illam m ina a re n a c e a and M. l a t y . The c o l o r o f th e t e s t s o f th e s e s p e c i e s i s t h a t o f th e a g g l u t i n a te d p a r t i c l e s . S in c e th e p a r t i c l e s a r e u s u a l l y c l e a r , a n g u la r m in e r a l g r a i n s , th e t e s t s a r e u s u a l l y w h ite to v e ry l i g h t g r e y , b u t th e y a r e d a r k e r i n a re aB w here th e s e d i m ents a re com posed o f d a rk v o l c a n ic p a r t i c l e s . Sponge s p i c u l e s and d ia to m f r u s t u l e B a r e r a r e l y , i f e v e r , u se d i n 192 t e s t fo r m a tio n . I n a l l f i v e s p e c i e s , t h e m in e r a l g r a i n s a r e t i g h t l y packed and f i r m l y cem ented fo rm in g r e l a t i v e l y sm o oth ly f i n i s h e d w a ll s u r f a c e s on b o th th e i n t e r i o r and e x t e r i o r . S in c e c o n c e n tr a te d s tr o n g a c i d s w i l l d e s t r o y th e w a lls o f m ost a g g l u t i n a t e d s p e c i e s , and s i n c e M lllam m ina and S pirolocam m ina w ith s to o d e x p o su re to c o n c e n tr a te d n i t r i c a c i d , th e cem ent em ployed by th e s e two g e n e r a was re g a rd e d a s s i l i c e o u s by E a r la n d (1933* 193*0. The c o n te n tio n t h a t o t h e r g e n e ra o f th e f a m ily R z e h a k in id a e have a s i l i c e o u s cem ent r e s t s on s i m i l a r l i n e s o f e v id e n c e (Cushman and C hurch, 1 9 2 9 ). Specim ens o f s e v e r a l s p e c i e s , some w ith w h ite w a l ls and o t h e r s w ith t h e more t y p i c a l brown w a l ls , w ere p la c e d i n a b e a k e r c o n ta in in g c o n c e n tr a te d h y d r o c h lo r ic a c i d j th e a c id was th e n b o i l e d f o r 30 m in u te s . Two s p e c i mens each o f th e w h ite - w a lle d s p e c i e s M iliam m lna a re n a c e a , M a r tin o ttie 1 1 a a n t a r c t i c a , and E g g e r e ll a p a r k e r a e v a r . B were undamaged by t h i s t r e a t m e n t , b u t th e t h i n brown w a l ls o f two specim ens o f Reophax d i s t a n s w ere q u ic k ly d e s tr o y e d . Two specim ens o f C rib ro s to m o id e s su b g lo b o s u s and one o f Hyperammlna c y l i n d r l c a , b o th s p e c i e s h a v in g t h i c k brown w a l l s , became f r i a b l e and p a r t i a l l y b ro k e n u p . One r o b u s t specim en o f Nodoslnum g a u s s ic u m . a l s o h a v in g a brown w a ll, how ever, r e t a i n e d i t s form a f t e r t h i s t r e a t m e n t , a lth o u g h i t a p p e a re d to be w eakened. The w h ite w a ll o f C r i t h i o n i n a pisu m h l s p i d a , a t h i c k f r i a b l e mass o f sponge s p i c u l e s and 193 m in e r a l g r a i n s , was q u ic k ly d e s tro y e d . T h is v e ry l i m i t e d e x p e rim e n t t o g e t h e r w ith th e o b s e r v a tio n s o f E a r la n d (1933* 1934) s u g g e s ts t h a t th e w h ite sm oothly f i n i s h e d w a l l s o f th e t e s t e d s p e c ie s o f th e A taxophragm iidae and R z e h a k in id a e a re more r e s i s t a n t to s tr o n g a c id s th an Borne s p e c i e s w ith brown w a ^ ls . The w h ite w a ll o f C r lth io n ln a o f th e fa m ily S accam in id ae i s a p p a r e n tly q u i t e d i f f e r e n t th a n t h e w h ite w a lls o f s p e c i e s o f th e f a m i li e s A taxophragm iidae and R z e h a k in id a e . H edley ( 1963) showed t h a t w h ite - w a lle d s p e c ie s o f th e g e n e ra C r i t h l o n i n a , D e n d ro n in a , P i l u l l n a , and T holaB ina have a t e c t i n o u s cem ent. The w a lls o f s p e c ie s w hich r e s i s t s tr o n g a c i d s p o s s i b l y c o n ta in a cem enting m a t e r i a l o th e r th a n t e c t i n . T h is m a t e r i a l h a s n o t been i d e n t i f i e d , however, and t h e e v id e n c e f o r a s i l i c e o u s cem ent i n a g g lu t i n a t e d f o r a m i n if e r a i s v e ry te n u o u s . In f a c t , th e s t r o n g e s t ev id en ce so f a r t h a t any f o r a m in lf e r a n s e c r e t e s s i l i c a a p p e a rs to be th e p e tr o g r a p h ic e v id e n c e p r e s e n t e d l a t e r t h a t "M i l l o l i n e l l a " sp . h a s a n o n a g g l u t i n a t e d w a ll o f o p a lin e s i l i c a . I n v e s t i g a t i o n o f th e w a ll o f t h i s s p e c ie s i s c u r r e n t l y b e in g fo llo w e d u p by R. L. K olpack and th e a u th o r . In th e S c o tia Sea and n o r th e r n W eddell Sea, M. a n t a r c - t i c a , E. p a r k e r a e v a r . B, and S. te n u i s have d i s t r i b u t i o n s t h a t can be e x p la in e d by-assum ing th e y have a s i l i c e o u s cem en t. The d i s t r i b u t i o n s o f M. a n t a r c t i c a and E . p a rk e ra e v a r . B have a lr e a d y been d is c u s s e d . I t was shown t h a t th e s e s p e c i e s a r e a b u n d a n t and p e r s i s t e n t i n th e a b y s s a l e n v iro n m e n t i n a r e a s w here d iato m s a r e a b u n d an t i n th e s e d i m e n ts. C o n v e rs e ly , th e y a re a b s e n t (e x c e p t f o r r a r e s p e c i mens o f M. a n t a r c t i c a a t one s t a t i o n ) from s e d im e n ts in w hich d ia to m s a r e a b s e n t o r p r e s e n t o n ly i n t r a c e am ounts. A ll e i g h t o c c u r r e n c e s o f S pirolooam m ina t e n u i s and a l l n i n e te e n a b y s s a l o c c u r r e n c e s o f ”^ . 11011061^ ” s p . a r e from sampleB i n w hich one o r th e o t h e r , o r b o th , o f th e fo rm er two s p e c i e s o c c u r . I t i s m ost l i k e l y t h a t d i s s o l v e d s i l i c a i n i n t e r s t i t i a l w aterB i s h i g h e r i n se d im e n ts w ith a b u n d an t d ia to m s , and i t i s a l s o l i k e l y t h a t f o r a m i n if e r a w hich em p lo y a s i l i c a cem ent o r s e c r e t e a s i l i c e o u s t e s t w a ll r e q u i r e a r e a s o n a b ly h ig h c o n c e n tr a ti o n o f d i s s o l v e d s i l i c a in t h e i r e n v iro n m e n t. R e l a t i o n s h i p b etw een A g g lu tin a te d F o ra m in ife r a w ith C a lc a re o u s W a lls and Those witTT P o s s i b l y S i l i c e o u s W alls In th e A ta x o p h ra g m iid a e , s p e c i e s w ith c a lc a r e o u s w allB and s p e c i e s w ith w h i t e , p o s s i b l y s i l i c e o u s w a l ls a r e c l o s e l y r e l a t e d . The m o rp h o lo g ie s o f M a r t in o t t ie 1 1 a m il- l e t t i and M. a n t a r c t i c a a r e s i m i l a r i n a l l im p o r ta n t g e n e r ic d e t a i l s i n c l u d i n g t h e i r m a n i f e s t a t i o n s o f dim orphism ( P l a t e X V II). An even c l o s e r r e l a t i o n s h i p iB p r o b a b le f o r E g g e r e l- l a p a r k e r a e v a r . A and E . p a r k e r a e v a r . B, two form s w hich a r e d i f f i c u l t to d i s t i n g u i s h from one a n o th e r . The r e l a t i o n s h i p betw een th e num ber o f cham bers and s i z e o f t e s t o f th e two v a r i e t i e s i s shown i n F ig u r e 3 7 . A p p lic a tio n o f d i l u t e h y d r o c h lo r ic a c i d to sp ecim en s o f v a r i e t y A, how e v e r , d e s tr o y s th e t e s t and c o m p le te ly d i s p e r s e s th e v e ry f i n e a g g l u t i n a t e d i n s o l u b l e p a r t i c l e s , w h ile th e same a c id does n o t r e a c t w ith sp e cim en s o f v a r i e t y B, Specim ens have n o t been found i n w hich a c i d rem oves p a r t o f th e te B t le a v in g a g g r e g a te s o f a g g l u t i n a t e d p a r t i c l e s j o in e d by an i n s o l u b le cem ent, and th u s v a r i e t y A and v a r i e t y B have n o t been o b se rv e d to i n t e r g r a d e . F u rth e rm o re , th e s o lu b le and i n s o lu b le form s have n o t b een o b s e rv e d i n th e same assem b l a g e s , F ig u re 4 5 , h ow ever, shows t h a t i f i n t e r g r a d a t i o n o r m u tu a l o c c u rr e n c e d o e s o c c u r , th e y a r e to. be e x p e c te d i n sam ples w ith i n t e r m e d i a t e f r e q u e n c i e s o f c a lc a r e o u s fo ra m i n i f e r a (a p p ro x im a te ly 20 p e r c e n t to 40 p e r c e n t c a lc a r e o u s s p e c im e n s ). Only a few sam p les o f t h i s k in d w ere a v a i l a b l e , and E g g e r e ll a p a r k e r a e was r a r e i n them . A nalogy w ith M a r t i n o t t i e l l a a n t a r c t i c a . h o w ever, s u g g e s ts t h a t E. p a rk e r a e v a r . B may i n f a c t o c c u r r a r e l y i n c a lc a r e o u s a s se m b la g e s. M a r t i n o t t i e l l a a n t a r c t i c a h a s a w h ite I n s o lu b le w a ll and o c c u r s w ith E . p a r k e r a e v a r . B i n th e S c o t ia Sea, b u t h a s a ls o been fo u n d , r e t a i n i n g ltB i n s o l u b l e w a l l , i n v e ry low p e r c e n ta g e s ( l e s s th a n 1 p e r c e n t ) i n t h r e e sam ples d om in ated by c a lc a r e o u s b e n th o n lc a (F ig u re 3 6 ) . W ith r e s e r v a t i o n b e c a u s e o f th e In a d e q u a te sam ple con t r o l i n c r i t i c a l a r e a s , th e a b se n c e o f i n t e r g r a d a t i o n b e tween s o l u b l e and I n s o l u b l e form s h a v in g th e m orphology o f Figure 37 E g g e r e ll a p a r k e r a e v a r , A and E. p a r k e r a e v a r . Bs Number o f Chambers P l o t t e d a g a i n s t L en g th o f TeBt 196 NUMBER O F CHAMBERS (EXCLUDING PROLOCULUS) 15- 10- O O o o o o o o o © o . © 0 § CD O o 00 o • o o o o o • o o o © o © e © < $ > o o o 5 - • o • EGGERELLA PARKERAE VAR. A O EGGERELLA PARKERAE VAR. B 0 c 1 0 m 01 0 . 1 0 0.20 I 0 3 0 LENGTH OF TEST IN MM. 0 .4 0 0.50 ;E. p a r k e r a e s u g g e s ts t h a t t h e two form s r e p r e s e n t s e p a r a t e s p e c i e s r a t h e r th a n p h e n o ty p e s o f a s i n g l e s p e c i e s . A l th oug h t h e s i m i l a r m o rp h o lo g ie s c o u ld be c o n v e r g e n t; th e s i z e / cham ber shape and a r r a n g e m e n t, and a p e r t u r a l c h a r a c t e r i s t i c s a r e so s i m i l a r t h a t d iv e r g e n c e c a u s e d by a d a p t a t i o n o f th e one form to a c a r b o n a te p o o r e n v iro n m e n t i s r e g a rd e d a s a more l i k e l y e x p l a n a t i o n . In t h i s c a s e , v a r i e t y A w ould p ro b a b ly be a n c e s t r a l , b e c a u s e , o f th e two k in d s o f w a l l s — c a lc a r e o u s and w h ite i n s o l u b l e - - t h e f o rm e r, i n th e w r i t e r ’s e x p e r ie n c e , i s more common i n th e A tax o p h rag m i i d a e . T h is i n f e r r e d e v o l u t i o n o f a form w hich s e c r e t e s a c a l c a r e o u s t e s t to a form w i t h a n o n - c a lc a r e o u s t e s t i n a c a r b o n a te - p o o r e n v iro n m e n t s u g g e s t s t h a t u n d e r s a t u r a t i o n o f th e m ilie u w ith r e s p e c t t o c a r b o n a te p l a c e s some s p e c i e s w hich m ust s e c r e t e a c a l c a r e o u s t e s t a s com pared w ith th o s e w hich form an i n s o l u b l e t e s t . DISTRIBUTION OP RADIOLARIA G e n e ra l I n b o tto m s e d im e n ts b e n e a th th e A n t a r c t i c C onvergence, m arked changes o c c u r In th e c o m p o s itio n o f r a d i o l a r i a n a s sem b lag es (H ays, 1 9 6 5) s i m i l a r to ch an g es w hich o c c u r in p l a n k t o n i c f o r a m i n i f e r a l a sse m b la g e s ( B l a i r , 1 9 6 5) . A l th o u g h o n ly two s p e c ie s o f p l a n k t o n i c f o r a m i n i f e r a n s a re a b u n d a n t i n se d im e n ts so u th o f th e A n t a r c t i c C onv ergence, Hays found seven ab u n d an t r a d i o l a r i a n s i n A n t a r c t i c s e d i m ents and t h r e e a d d i t i o n a l o n es were fo u n d by th e a u th o r . T here i s enough d i v e r s i t y i n A n t a r c t i c r a d i o l a r i a n s , t h e r e f o r e , t h a t d i s t i n c t i v e a sse m b la g e s may b e c h a r a c t e r i s t i c o f d i s t i n c t i v e e n v iro n m e n ts . B ecause r a d i o l a r i a n d i s t r i b u t i o n s i n s e d im e n ts o f th e se a f l o o r m ust be u n d e r s to o d b e f o r e e a r l i e r A n t a r c t i c c lim a te s can be i n t e r p r e t e d from th e r a d i o l a r i a n s i n d e e p -s e a c o r e s , th e p r e s e n t s tu d y was u n d e r' ta k e n to d e f in e r a d i o l a r i a n d i s t r i b u t i o n a l t r e n d s i n s e d i m ents o f th e S c o tia and W eddell Seas and to r e l a t e them a s f a r a s p o s s i b l e to e n v iro n m e n ta l f a c t o r s . R a d io la r ia n Abundance The abundance o f r a d i o l a r i a n s f a l l s o f f so u th w a rd from 199 200 1 0 ,0 0 0 to 2 0 ,0 0 0 specim ens p e r gram o f d ry sed im en t n o r th o f 56°S In th e S c o t ia Sea to 0 to 100 specim ens p e r gram s o u th o f 62°S In th e W eddell Sea (F ig u re 3 8 ) . R a d io l a r i a n s a r e l e s s a b u n d an t i n se d im e n ts n e a r i s l a n d s th an i n a b y s s a l se d im e n ts from s i m i l a r l a t i t u d e s r e f l e c t i n g h ig h e r sed im en t a t i o n r a t e s n e a r th e i s l a n d s and p o s s i b l y la c k o f t o l e r a n c e o f r a d i o l a r i a n s f o r n e a r - s h o r e h a b i t a t s . C om parison o f r a d i o l a r i a n abundance (F ig u re 3 8) w ith t h a t o f d iato m s (F ig u re 14) r e v e a l s s i m i l a r i t i e s ! se d im e n ts p o o r i n d iato m s c o n ta in few r a d i o l a r i a n s , w h ile se d im e n ts r i c h i n d iato m s c o n ta in many. The m ost i n t e r e s t i n g d i f f e r en ce i s t h a t th e g r e a t e s t c o n c e n tr a tio n o f d iato m f r u s t u l e s o c c u rs i n se d im e n ts o f th e s o u th e a s te r n S c o tia Sea where th e abundance o f r a d i o l a r i a n s f a l l s o f f m arkedly so u th w a rd . F au n al A n a ly s is Seven s p e c ie s o c c u r r in g a t f r e q u e n c ie s o f more th a n 5 p e r c e n t i n some r a d i o l a r i a n asse m b la g es in se d im e n ts from th e S c o t ia and W eddell Seas a re Spongoplegma a n ta r c tic u m , H e lo th o lu s h i s t r i c o s a , P e ro m e lis s a d e n t l c u l a t a , Spongurus p y lo m a tlc u s , S p o n g o tro ch u s g l a c l a l i s , L l t h e l i u s n a u t l l o i d e s , and P ru n o p y le a n t a r c t i c a . S e v e ra l s p e c ie s o f sm a ll r a d i o l a r i a n s , r e f e r r e d to h e re a s " s p h a e r id s " b e c a u se o f t h e i r s p h e r i c a l sym m etry, a r e s i g n i f i c a n t a s a g ro u p , a lth o u g h I n d i v i d u a l l y th e y u s u a l l y o c c u r a t low f r e q u e n c ie s . T hree o t h e r s p e c ie s w hich were c o n s id e re d dom inant A n t a r c t ic F ig u r e 38 R a d i o l a r i a Number o f sp e cim en s p e r gram o f Dry S edim ent 201 2 0 2 »• 40* iooo6 BATHYMETRY IN METERS so* IUTH SATOWICI ISLANDS g. 1 0 0 0 0 * 2 0 0 0 - SOUTH ORKNE' 100 ' I | <1000 1000-10000 >10000 A *T 4 *C T tC SO * RADIOLARIAN NO. /GM FIGURE 38 203 s p e c i e s b y H ays, T r i c e r a s p y r i s a n t a r c t i c a , T h e o l c a l y p t r a d a v i s i a n a , and B o try o p y le ? a n t a r c t i c a , o c c u r r e d i n m ost s a m p le s , b u t th e y w ere n o t a b u n d a n t. D u rin g p r e l i m i n a r y a n a l y s i s , f i v e s p e c i e s o r s p e c i e s g ro u p s w ere s e l e c t e d f o r f u r t h e r s tu d y b e c a u s e th e y a r e a b u n d a n t, h a v e s i g n i f i c a n t d i s t r i b u t i o n a l p a t t e r n s , and a r e e a s i l y d i s t i n g u i s h e d a t low m a g n i f i c a t i o n s o f a s t e r e o s c o p ic m ic ro s c o p e (60 d i a m e t e r s ) . R e l a t i v e f r e q u e n c i e s o f t h e s e s p e c i e s and s p e c i e s g ro u p s w ere c a l c u l a t e d a g a i n s t a l l o t h e r r a d i o l a r i a n s k e l e t o n s i n c o n t r a s t to t h e m ethod o f Hays ( 1 9 6 5 )' who c a l c u l a t e d d o m in a n ts a g a i n s t o t h e r dom i n a n t s ; t h e r e f o r e , i n a g iv e n sa m p le , th e r e l a t i v e f r e q u e n c y o f an y s p e c i e s a p p e a r s s l i g h t l y lo w e r th a n w ou ld be i n d i c a t e d b y t h e m ethod o f H ays. S g o n g o p le |m a _ a n ta rc tic u m T h is l a r g e a n d d i s t i n c t i v e r a d i o l a r i a n o c c u r s a t low r e l a t i v e f r e q u e n c i e s (F ig u re 3 9 ) i n a r e a s w here r a d i o l a r i a n s a r e a b u n d a n t i n t h e s e d im e n ts , even l e s s th a n 1- p e r c e n t a ro u n d S o u th G e o rg ia and i n s e v e r a l sa m p le s fro m t h e s o u t h e rn p a r t o f the- S c o t i a S e a . I t s r e l a t i v e ab u n d an c e i s g r e a t e r b o t h to t h e n o r t h i n t h e one sam ple l o c a t e d n e a r th e mean p o s i t i o n o f th e A n t a r c t i c C o n v e rg en c e, and to th e s o u th i n t h e W ed d e ll S ea. S o u th o f a l i n e p a r a l l e l i n g th e s o u th e r n p a r t o f t h e S c o t i a R id g e , i t e x c e e d s 10 p e r c e n t o f t h e t o t a l , and i n one sam ple from th e n o r t h - c e n t r a l Wed- Figure 39 Spongoplegma antarcticum Percent of Total Radiolarians 204 205 1 I BATHYMETRY IN METERS so* S O W " SOUTH GEOROI ? ORKNEYS 10-50 A M T A *C T IC ----- C tR C L C PERCENT SPONGOPLEGMA ANTARCTICUM FIGURE 39 206 d e l l S ea, i t c o m p rise s 73 p e r c e n t o f a l l r a d i o l a r i a n s . An e n t i r e l y d i f f e r e n t im p re ss io n o f th e d i s t r i b u t i o n o f t h i s B p ecies i s o b ta in e d i f abundance i s e x p re s s e d a s th e number o f specim ens o c c u r r in g in a gram o f d ry se d im e n t (F ig u re 4 o ) . More th a n 100 p e r gram o c c u r i n m ost sam ples from th e n o rth w e s t S c o tia Sea where t o t a l r a d i o l a r i a n num b e r s ex ceed 1 0 ,0 0 0 . A lthough £3. a n ta r c tic u m was th e dom i n a n t s p e c ie s o f th e W eddell S ea, a c t u a l l y few er th a n 10 specim ens p e r gram o f sed im en t a r e found i n some sa m p le s. M o rp h o lo g ic a lly , specim ens o f _S. a n ta r c tic u m from th e n o r th c e n t r a l W eddell Sea d i f f e r from th o s e from .th e S c o tia Sea and from aro u n d th e S outh Sandwich I s l a n d s . In s p e c i mens from th e S c o tia Sea th e c o r t i c a l s h e l l s a r e f r e q u e n t ly h e a v i ly s i l i c i f i e d and m e d u lla ry meshworks a re u s u a l l y p r e s e n t , w h ile i n specim ens from th e W eddell Sea th e c o r t i c a l s h e l l s a re an open mesh and t h e r e i s l i t t l e , i f any, e v i dence o f a m e d u lla ry meshwork. Sam ples from th e n o r th e r n m argin o f th e W eddell Sea ( i . e . , USC 1024) c o n ta in b o th fo rm s. The two form s have been p la c e d i n d i f f e r e n t g e n e ra : T h eco sp h aera a n t a r c t i c a f o r th o s e w ith a m e d u lla ry meshwork, and C enosphaera a n t a r c t i c a f o r th o se w ith o u t (N akaseko, 1 9 5 9 ). Hays (19^5) p la c e d th e s e two names i n synonymy w ith S,. a n ta r c tic u m s u g g e s tin g t h a t th e m e d u lla ry meshwork d e v e lo p s l a t e r i n th e l i f e c y c le o f th e a n im al th a n th e c o r t i c a l s h e l l . Assuming th e m e d u lla ry meshwork i s a l a t e r d e v e lo p m e n t, th e n specim ens o f Spongoplegma a n ta r c tic u m from Figure 40 Spongoplegma antarcticum Number per gram of Dry Sediment 207 2 0 8 40* 'O O l SOI IKNEYS «• 4 N T A K C riC SPONGOPLEGMA ANTARCTICUM NQ/GM FIGURE 40 th e S c o tia Sea have u s u a l ly co m p leted a s ta g e o f m o rphologic developm ent t h a t th e W eddell Sea specim ens have n o t . The d i f f e r e n c e i n s i l i c i f i c a t i o n o f specim ens from th e two a r e a s c a n n o t he e x p la in e d by th e c o n c e n tr a tio n o f d is s o lv e d s i l i c a i n th e w a te r b e ca u se s i l i c a i s a s ab u n d an t a t a l l d e p th s i n th e W eddell Sea a s th e S c o tia S ea. S p h a e rid s The s p h a e r id s in c lu d e a l l s p e c ie s w ith s p h e r i c a l sym m etry o t h e r th a n th e d i s t i n c t i v e Spongoplegma a n ta r c t i c u m . These sm a ll s p h e re s a re more th an 3° p e r c e n t o f th e r a d i o l a r i a n s i n th e W eddell Sea, l e s s th a n 10 p e r c e n t in th e n o r th e r n S c o tia S ea, and 14 p e r c e n t i n th e sam ple n e a r th e mean p o s i t i o n o f th e A n ta r c tic C onvergence (F ig u re 4 l ) . T h e ir d i s t r i b u t i o n a l p a t t e r n i s v e ry s i m i l a r to t h a t o f S, a n ta r c tic u m (F ig u re 3 9 ) , a lth o u g h r e g i o n a l d i f f e r e n c e s in r e l a t i v e fre q u e n c y f o r th e s p h a e r id s a re n o t a s l a r g e a s f o r £> . a n ta r c t i c u m . P e ro m e lis s a d e n t i c u l a t a and H e lo th o lu s h l s t r i c o s a (n o t d i s t i n g u i s h e d ) B oth o f th e s e s p e c ie s a r e sm a ll and b e ll-B h a p e d . A d u lt specim ens a re e a s i l y d i s t i n g u i s h e d , b u t s m a lle r s p e c i mens a re o f t e n d i f f i c u l t to d i s t i n g u i s h w ith th e sm a ll mag n i f i c a t i o n s u se d i n t h i s s tu d y . For t h i s r e a s o n , th e two s p e c ie s were c o u n te d t o g e t h e r . Figure 4l S p h a e r id R a d i o l a r i a n s P e r c e n t o f T o t a l R a d i o l a r i a n s 2 1 0 2 1 1 BATHYMETRY IN METERS SO’ w o o SOUTH SANDWICH .ISLANDS ■5ooo 2. 0 IKNEYS PERCENT SPHAERIDS FIGURE 41 212 The d i s t r i b u t i o n o f r e l a t i v e f r e q u e n c i e s o f Perom e1 1 s - s a - H e lo t h o l u s ( F ig u r e 42) c o n t r a s t s w i t h t h a t o f Spongo- legm a a n t a r c t i c u m . I n th e S c o t i a Sea w h ere r a d i o l a r i a n s a r e a b u n d a n t i n th e s e d im e n ts , t h e s e two s p e c i e s t o g e t h e r form m ore th a n 50 p e r c e n t o f th e a s s e m b la g e s w h ile i n th e W ed d e ll Sea w here s e d im e n ts h a v e few r a d i o l a r i a n s an d S, a n t a r c t i c u m d o m in a te s , t h e s e two s p e c i e s a r e l e s s th a n 10 p e r c e n t o f th e a s s e m b la g e s . In some sa m p le s fro m t h e S c o t i a Sea t h e r e a re m ore th a n 1 0 ,0 0 0 sp e c im e n s o f P erom e11s s a - H e lo th o lu s p e r gram o f s e d im e n t, w h ile i n sa m p le s fro m t h e n o r t h c e n t r a l W ed d ell Sea t h e r e a r e l e s s th a n 10 sp e c im e n s p e r gram o f s e d im e n t ( F i g u r e -43)# S p o n g u ru s p y lo m a tic u s SponguruB p y lo m a tic u s i s n o t l i s t e d a s a d o m in a n t i n . H a y s' ( 1 9 6 5) s tu d y o f A n t a r c t i c r a d i o l a r i a n s . I n s e d im e n ts o f th e S c o t i a S e a , h o w e v er, i t u s u a l l y e x c e e d s 5 p e r c e n t o f th e t o t a l , and a lo n g t h e s o u t h e r n p a r t o f t h e S c o t i a R id g e and i n th e S o u th S andw ich T re n c h , i t o c c u r s i n f r e q u e n c i e s o f more th a n 10 p e r c e n t , I n some c a s e s m ore th a n 20 p e r c e n t ( F ig u r e 4 4 ) . I n g e n e r a l , t h e r e l a t i v e f r e q u e n c y o f S , p y l o m a tic u s r e a c h e s maxima I n t h e r e g i o n w h ere t h e r e a r e s h a r p e s t c h an g e s i n r e l a t i v e f r e q u e n c y o f Spongoplegm a a n t a r c tic u m and Perom e11s s a -H e lo t h o l u s . I n th e n o r t h c e n t r a l Wed d e l l S e a , r e l a t i v e f r e q u e n c i e s o f S . p y lo m a tic u s f a l l to l e s s th a n 1 p e r c e n t o f th e t o t a l . Figure 42 P e ro m e lis s a d e n t i c u l a t a and H e lo th o lu s h is tr 'i'c o s a (n o t d i s t i n g u i s h e d ) P e rc e n t o f T o ta l R a d i o l a r i a n s 213 214 40* SO* BATHYMETRY IN METERS 50 SOUTH . GEOROU GEOROli • 000/ SOUTI IO W H 50 tOOO' •0 * ’2 0 0 0 ' SOUTH ORKNEYS T o< 6 5 * PERCENT PEROMELISSA DENTICULATA ANO HELOTHOLUS HISTRICOSA (NOT DISTINGUISHED) FIGURE 42 Figure 43 Perom elissa d e n tic u la ta and H elotholu s hlB tricoB a (not d istin g u ish e d ) Number p e r gram o f Dry S e d im e n t 215 216 90*« 40* M * t l 'W BATHYMETRY IN METERS GEORGI 2 ^ £ SOUTH ORKNEYS - A N T A R C T IC — — C tftC L C — — — t t 'W PEROMELISSA DENTICULATA AND HELOTHOLUS HISTRICOSA (NOT DISTINGUISHED) NO./GM. FIGURE 4 3 Figure 44 Spongurus p y lo m a tic u s P e rc e n t o f T o ta l R a d io l a r i a n s 217 218 BATHYMETRY IN METERS GEOROI 7 SOUTH SANDWICH ISLANDS SOUTH ORKNEYS t 4 * r 4 * C r / C — — — — C t*C L £ — — PERCENT SPONGURUS PYLOMATICUS FIGURE 44 219 D is c - s h a p e d R a d l o l a r i a n s The d i s c - s h a p e d r a d l o l a r i a n s I n a l l sam ples a r e p r e d o m in a n tly S p o n g o tro c h u s g l a c l a l i s P o p o fsk y , b u t a s much a s a t h i r d o f them I n some a b y s s a l sa m p le s a r e Spongopyle o sc u l o s a D r e y e r . O th e r d i s c - s h a p e d r a d l o l a r i a n s a r e p r e s e n t a t low f r e q u e n c i e s I n th e s a m p le s . I n t h e n o r t h c e n t r a l W ed d ell S e a , d is c - s h a p e d r a d l o l a r i a n s a r e v e ry r a r e a s a r e o t h e r r a d l o l a r i a n s e x c e p tin g s p h a e r i d s and Spongoplegm a a n t a r e t i c u m (F ig u re 4 5 ) . E l s e w here I n t h e a r e a th e y o c c u r a t f r e q u e n c i e s o f 8 to 26 p e r c e n t o f t h e r a d l o l a r i a n s , w ith a te n d e n c y f o r th e h ig h e s t f r e q u e n c i e s to o c c u r a lo n g th e s o u th e r n and e a s t e r n S c o tia R idge and n e a r S o u th G e o rg ia . Summary o f t h e R a d i o l a r i a n D i s t r i b u t i o n s The c a t e g o r y o f P e r o m e lis s a - H e lo th o lu s w hich d o m in a tes r i c h and r e l a t i v e l y d i v e r s e r a d i o l a r i a n a sse m b la g e s in th e S c o t i a S ea d e c r e a s e s i n r e l a t i v e fre q u e n c y tow ard th e s o u th and s o u t h e a s t a s S p o n g u ru s p y lo m a tic u s an d d is c - s h a p e d r a - d i o l a r i a n s i n c r e a s e i n r e l a t i v e f r e q u e n c y . The a r e a o f h i g h e s t r e l a t i v e f r e q u e n c i e s o f S_. p y lo m a tic u s c l o s e l y c o r re s p o n d s to t h e t r e n d o f th e s o u th e r n and e a s t e r n S c o tia R id g e , b u t h ig h r e l a t i v e f r e q u e n c i e s o f d is c - s h a p e d r a d l o l a r i a n s o c c u r o v e r a l a r g e r a r e a . F a r t h e r s o u th i n th e n o r t h - c e n t r a l W ed d ell S ea s p a r s e r a d i o l a r i a n a sse m b la g e s Figure 45 D is c -s h a p e d R a d lo l a r i a n s P e r c e n t o f T o ta l R a d l o l a r i a n s 2 2 0 221 40* SO* BATHYMETRY IN METERS so * G E O R G IA SOUJ iLANI .4001 IOUTH ORKNEYS *N T *a C T IC SO* PERCENT DISC-SHAPED RADIO LARIANS FI CURE 45 2 2 2 a r e d o m in a te d b y s p h e r i c a l r a d l o l a r i a n s : Spongoplegm a a n t - a r c t ic u m and a g ro u p o f s m a lle r s p e c i e s h e re c a l l e d s p h a e - r l d s . I n W ed d e ll Sea sp ecim en s o f S . a n ta r c tlc u m th e c o r t i c a l s h e l l s a r e t h i n open m eshes and t h e r e a r e no m e d u lla ry m eshw orks i n d i c a t i n g t h a t s i l i c i f i c a t i o n d id n o t p r o c e e d to th e s t a t e re a c h e d by m ost o f th e S c o t i a Sea sp e c im e n s o f t h i s s p e c i e s w h ich a r e v e ry r o b u s t . D ep th H a b i t a t s o f A n t a r c t i c R a d lo l a r i a n s B e cau se d i f f e r e n t d e p th l e v e l s i n t h e A n t a r c t i c Ocean h av e d i f f e r e n t p h y s i c a l p r o p e r t i e s an d d i f f e r e n t s e n s e s o f m o tio n , a know ledge o f t h e d e p th h a b i t a t s o f r a d l o l a r i a n s i s i m p o r t a n t to an u n d e r s ta n d in g o f t h e i r g e o g ra p h ic d i s t r i b u t i o n s . I n t h e a b se n c e o f s t u d i e s o f d e p th h a b i t a t s o f r a d l o l a r i a n s b a s e d on c o l l e c t i o n s from th e w a te r colum n w ith c l o s i n g n e t s , i n f e r e n c e s may be drawn by a n a ly z in g th e o c c u r r e n c e o f r a d l o l a r i a n s i n b o tto m s e d im e n ts ta k e n a t d i f f e r e n t d e p th B . A n a ly z in g m a t e r i a l c o l l e c t e d from th e I n d ia n A n t a r c t i c Ocean i n t h i s way, R le d e l (1958) c o n c lu d e d , w ith r e s e r v a t i o n s b e c a u s e o f th e s m a ll number o f s a m p le s, t h a t in d ig e n o u s A n t a r c t i c o r c o ld b i p o l a r s p e c ie s p o p u l a t e th e A n t a r c t i c S u r f a c e W ater w h ile c o sm o p o lita n s p e c i e s a r e c o n f in e d to t h e Warm Deep L a y e r. S p o n g o tro c h u s g l a c i a l i B , H e lo th o lu s h l s t r i c o s a , and P e r o m e lis s a d e n t i c u l a t a w ere l i s t e d among th e s p e c i e s l i v i n g i n t h e s u r f a c e w a te r ; a d e e p e r h a b i t a t was p o s t u l a t e d f o r Spongopyle o s c u l o s a . I n - 223 t e r p r e t a t i o n s f o r o t h e r s p e c i e s im p o r ta n t t o t h i s s tu d y w ere n o t g iv e n . Ten sam p les c o l l e c t e d fro m d e p th s o f 330 to 3700 me t e r s on th e s lo p e s o u th o f S o u th G e o rg ia I s l a n d a r e i n many ways f a v o r a b l e f o r d e p th a n a l y s i s o f r a d i o l a r i a n a s sem b lag es i n b o tto m s e d im e n ts . A l l th e sa m p le s a r e f a r from la n d , and l a t e r a l v a r i a t i o n s o f r e l a t i v e r a d i o l a r i a n f r e q u e n c i e s i n t h i s a r e a a re l e s s th a n a lo n g th e s o u th e r n and e a s t e r n S c o t i a R id g e . A s h a llo w e r sam ple (200 m e te rs ) from v e ry n e a r S o u th G e o rg ia was n o t i n c l u d e d i n t h i s a n a l y s i s b e c a u s e t h e r a r e r a d i o l a r i a n sp e cim en s a r e worn and m in e r a l i z e d , i n d i c a t i n g p r o b a b le d e r i v a t i o n from o l d e r s e d im e n ts . A p l o t o f r e l a t i v e f r e q u e n c i e s a g a i n s t d e p th f o r th e f i v e r a d i o l a r i a n c a t e g o r i e s i n t h e s e te n sam p les (F ig u r e 46) shows t h a t B p h a e rid s , Spongoplegm a a n ta r e t i c u m and S pongurus p y lo m a tic u s t o g e t h e r compose l e s s th a n 5 p e r c e n t o f th e r a d i o l a r i a n a s s e m b la g e s above 1000 m e te r s , b u t i n t h e d e e p e s t sam ple th e y a r e 13 p e r c e n t o f th e t o t a l . D is c -s h a p e d r a d l o l a r i a n s , a lm o s t a l l o f w hich w ere Spongo- tr o c h u s g l a c l a l i s i n sa m p le s from above 750 m eterB , d e c re a s e g r a d u a l l y from 25 p e r c e n t i n t h e s h a l lo w e s t a sse m b la g e to 9 p e r c e n t i n th e d e e p e s t . The s m a ll v a r i a t i o n s i n r e l a t i v e fre q u e n c y o f P e r o m e lis s a - H e lo th o lu s (52 to 60 p e r c e n t ) i s n o t r e l a t e d to d e p th . From t h i s a n a l y s i s i t i s c l e a r t h a t S. g l a c i a l i B and Perom e11s s a - H e l o th o l u s a r e a b u n d a n t' above 330 m e te r s . Figure 46 R e l a t i v e F r e q u e n c ie s o f D om inant R a d i o l a r i a n S p e c ie s a n d S p e c ie s G roups i n S e d im e n ts o f t h e S lo p e S o u th o f S o uth G e o rg ia I s l a n d P l o t t e d a g a i n s t D ep th 224 BATHYMETRY I N METERS PERCENTAGE IN RADIOLARIAN ASSEMBLAGES 8 10 12 14 16 18 2 0 2 2 2 4 2 6 4 0 5 0 6 0 1000 2000- SPHAERIDS SPONGURUS DISCS 3 0 0 0 - HELOTHOLUS-PEROMELISSA 3 4 0 0 0 225 226 ’ T h is i s s u b s t a n t i a t e d by th e r e l a t i v e abundance o f th e s e s p e c ie s on th e S o u th Orkney s h e l f a t 260 and 370 m e te rs ( F ig u re s 5^ and 4 2 ) . Spongurus p y lo m a tic u s , s p h a e r i d s , and Spongoplegma a n ta r c tic u m may l i v e p r i m a r il y a t g r e a t e r d e p th s a lth o u g h i n d i v i d u a l s o c c u r as sh a llo w a s 330 m e te rs . In a g re e m e n t, j3. p y lo m a tic u s i s l e s s th an 2 p e r c e n t i n th e S o u th Orkney s h e l f sam ples w h ile i t i s g e n e r a l l y more th a n 10 p e r c e n t in d e e p e r sam ples from th e s o u th e rn S c o t ia R idge (F ig u re 4 4 ) . S p h a e rid s a r e a l s o r a r e i n S outh Orkney s h e l f sam ples (F ig u re 4 l ) , and S. a n ta r c tic u m does n o t o c c u r a t a l l in th e s h a llo w e s t sam ple. These c o n c lu s io n s on d e p th h a b ita tB o f r a d l o l a r i a n s m ust be r e g a r d e d a s t e n t a t i v e , f o r l a t e r a l c h a n g e s, p o s s i b l y a s s o c i a t e d w ith c o a s t a l i n f l u e n c e s , may be su p erim p o sed on th e p r o g r e s s i v e chang es i n r e l a t i v e f r e q u e n c ie s w ith d e p th r e l a t e d to th e s p e c i e s ' d e p th h a b i t a t . F a c to r s I n f l u e n c in g R a d io la r ia n D i s t r i b u t i o n s D i s t i n c t i v e r a d i o l a r i a n p o p u la tio n s may be c h a r a c t e r i s t i c o f d i f f e r e n t A n t a r c t i c w a te r m asses a s h a s been demon s t r a t e d f o r m ac ro p la n k to n i n th e S c o tia and W eddell S eas (M a ck in to sh , 1 9 3 4 ). In p a r t , how ever, th e m arked r e g i o n a l v a r i a t i o n s i n r a d i o l a r i a n th a n a to c o e n o s e s i n t h i s a r e a a p p e a r to r e q u i r e e n v iro n m e n ta l g r a d i e n t s f o r w hich t h e r e i s l i t t l e d i r e c t e v id e n c e . 227 H y d ro g rap h ic b o u n d a r ie s t h a t may i n f l u e n c e r a d i o l a r i a n d i s t r i b u t i o n s a r e m ost p ro n o u n ce d i n th e c e n t r a l and s o u th e rn S c o tia S ea. The co n v erg en c e r e g i o n betw een s u r f a c e wa t e r s moving e a s tw a rd from th e B e llin g s h a u s e n Sea and c o ld e r s u r f a c e w a te r s m oving n o r th e a s tw a r d from th e W eddell Sea t r e n d s d ia g o n a lly a c r o s s th e S c o t ia Sea ( F ig u r e 4 ) . T h is c o n v e rg e n c e , c o r r e s p o n d in g to th e s o u th e r n l i m i t o f many r e l a t i v e l y warm w a te r s p e c i e s o f m a c r o p la n k te r s (M ackinto sh , 1 9 3 4 )} may s i m i l a r l y r e s t r i c t Perom e11s s a - H e l o th o l u s , s u r fa c e w a te r r a d l o l a r i a n s , c a u s in g th e i n i t i a l sou thw ard d e c r e a s e o f th e s e form s i n b o th r e l a t i v e fre q u e n c y and abun dance i n se d im e n ts ( F i g u r e s 42 and 4 3 ) . In p o s s i b l e con t r a d i c t i o n o f t h i s i n t e r p r e t a t i o n , how ever, b o th P e ro m e lis s a d e n t i c u l a t a and H e lo th o lu s h i s t r l c o s a have A n t a r c t ic d i s t r i b u t i o n s , and Hays ( 1 9 6 5) found t h a t P. d e n t i o u l a t a a c t u a l l y a p p e a re d to i n c r e a s e i n r e l a t i v e fre q u e n c y n e a r th e A n t a r c t ic c o n t i n e n t . At g r e a t e r d e p th s , te m p e ra tu re d e c r e a s e s so u th w ard i n t h e s o u th e rn and s o u t h e a s te r n S c o tia Sea ( F ig u r e s 9» 10, and l l ) . H ig h e s t r e l a t i v e f r e q u e n c ie s o f Spongurus p y l o m a t ic u s . a p p a r e n t l y a d e e p e r w a te r s p e c i e s , o c c u r i n se d im e n ts b e n e a th th e c o ld e r deep w a te rs a lo n g th e s o u th e rn and e a s t e r n S c o t i a R id g e. T here i s no e v id e n c e f o r a s i g n i f i c a n t h y d ro g r a p h ic b o u n d a ry , how ever, i n th e a re a o f th e s o u th e rn S c o t i a R idge and n o r t h e r n W eddell Sea where th e abundance o f r a d l o l a r i a n s f a l l B o f f to th e so u th a s s p h a e r id s and Spongoplegm a a n ta r c tic u m I n c r e a s e r e l a t i v e 228 to o t h e r r a d i o l a r i a n s i n th e b o tto m s e d im e n ts . C o n c u rre n t w ith th e t r a n s i t i o n from r a d i o l a r i a n a s sem b lag es d o m in ated by P e ro m eli s s a - H e lo th o lu s i n th e n o r t h to th o s e d om in ated by s p h a e r id s and Spongoplegm a a n ta r c tic u m i n th e s o u th , th e abundance o f b o th r a d l o l a r i a n s and d ia to m s i n th e s e d im e n ts f a l l s o f f m ark e d ly . A lth o u g h s e d im e n ta t i o n r a t e s may be h ig h e r i n th e W eddell Sea th a n i n th e S c o t ia S ea, i t i s h i g h ly im p ro b a b le t h a t d e t r i t a l d i l u t i o n a lo n e i s a d e q u a te to e x p la in th e so u th w a rd r e d u c t io n i n r a d i o l a r i a n ab u n d an ce. B ecause r a d l o l a r i a n s a r e 1000 tim e s l e s s a b u n d a n t i n W eddell Sea se d im e n ts th a n i n S c o t ia Sea s e d im e n ts ( F ig u re 3 8 ) , th e s e d im e n ta tio n r a t e s on a w e ig h t p e r u n i t a re a b a s i s w ould have to be more th a n 1000 tim e s a s g r e a t i n th e W eddell S ea a s i n th e S c o t ia Sea i f t h i s w ere r e a l l y . t h e e x p la n a t i o n . Even Spongoplegm a a n ta r c t i c u m , th e dom inant s p e c ie s i n W edd ell Sea a s s e m b la g e s , i s 10 tim e s more a b u n d an t i n S c o t ia S ea s e d im e n ts th a n i n W eddell Sea se d im e n ts (F ig u re 4 o ) , th u s r e q u i r i n g a d i f f e r e n c e in s e d im e n ta tio n r a t e s o f 10 tim e s b etw een th e two a r e a s i f t h i s s p e c i e s o n ly i s added to and p r e s e r v e d i n th e s e d i m ents a t e q u a l r a t e s th ro u g h o u t t h e s tu d y a r e a . I t i s a ls o im p ro b a b le t h a t th e p o o r r a d i o l a r i a n a s sem b lag es d o m in ated by s p h e r i c a l r a d l o l a r i a n s a re r e s i d u e s l e f t by th e d i s s o l u t i o n o r a b r a s io n o f o t h e r s p e c i e s . The s p h e r i c a l r a d l o l a r i a n s a r e l e s s r o b u s t and t h e r e f o r e p ro b a b ly l e s s r e s i s t a n t to s o l u t i o n o r a b r a s io n th a n Spongo- 229 trochus g la c ia liB or Spongurus pylomaticus or even some i sp ecim en s o f P e ro m e lis s a d e n t i c u l a t a . F u rth e rm o re , r a d i o l a r i a n sp ecim en s from th e W eddell Sea do n o t a p p e a r to be e i t h e r c o rro d e d o r a b ra d e d . The b a r s i n th e c o r t i c a l s h e l l o f W eddell Sea specim ens o f S. a n ta r c tic u m a re t r a n s l u c e n t and t h e r e i s no e v id e n c e o f s o l u t i o n p i t t i n g . The s k e l e t o n s a r e so d e l i c a t e t h a t such b re a k a g e a s was n o te d c o u ld e a s i l y have been c a u se d by l a b o r a to r y p r o c e s s in g . P o o rly s i l i c i f i e d W eddell Sea r a d l o l a r i a n s a r e p o s s i b l y a b e r r a n t i n d i v i d u a l s a n a lo g o u s to f o r a m i n if e r a n s w ith d i s t o r t e d m orphology o c c u r r in g i n e c o l o g i c a l l y m a r g in a l e n v iro n m e n ts (A rn a l, 1 9 5 5 ). These p o s s i b l y a b e r r a n t s p e c i mens o c c u r r in g i n p o o r r a d i o l a r i a n a s se m b la g e s , i n a d d i t i o n to th e a lm o s t co m p lete a b sen c e o f s p e c ie s w hich a re d om inan t i n s e d im e n ts where r a d l o l a r i a n s a r e a b u n d a n t, su g g e s t t h a t th e s p h e r i c a l r a d l o l a r i a n s c h a r a c t e r i s t i c o f th e W eddell Sea a r e s u r v i v o r s i n an e c o l o g i c a l l y m a r g in a l e n v iro n m e n t . The im p o v e ris h e d r a d i o l a r i a n a sse m b la g e s from th e n o r t h - c e n t r a l W eddell Sea o c c u r i n se d im e n ts c o n ta in i n g few d ia to m f r u s t u l e s , w h ile r a d i o l a r i a n r i c h a sse m b la g e s from th e S c o t ia Sea o c c u r i n se d im e n ts c o n ta in in g a b u n d an t d ia to m f r u s t u l e s . I t i s s u g g e s te d t h a t th e abundance o f f r u s t u l e s i n se d im e n ts o f th e S c o tia Sea i s i n d i c a t i v e o f h ig h d ia to m p r o d u c t i v i t y in th e o v e r ly in g w a te r s w h ile th e r a r i t y o f f r u s t u l e s i n se d im e n ts o f th e n o r t h - c e n t r a l Wed 230 d e l l Sea r e f l e c t s low d ia to m p r o d u c t i v i t y . The en v iro n m en t o f th e n o r t h - c e n t r a l W eddell Sea I s c o n s id e r e d m a rg in a l f o r r a d l o l a r i a n s b e c a u se o f low p r o d u c t i v i t y o f d ia to m s, Im por t a n t p rim a ry p r o d u c e r s o f o rg a n ic m a t t e r . Two q u a n t i t a t i v e p h y to p la n k to n s t u d i e s i n th e S c o tia Sea and W eddell Sea a r e a s have p ro d u c e d d i s p a r a t e r e s u l t s . H a rt (193*0 foun d h ig h s ta n d in g c ro p s o f p h y to p la n k to n th ro u g h o u t t h i s a r e a in c lu d in g th e W eddell Sea s o u th o f th e Sou th Sandw ich I s l a n d s . E l-S a y e d and M a n d e lli ( 1965) m eas u r e d g e n e r a l l y h ig h , b u t v a r i a b l e , p rim a ry p r o d u c t i v i t y i n th e a r e a o f d ia to m ooze i n th e s o u t h e a s te r n S c o tia S e a , b u t c o n s i s t e n t l y low p rim a ry p r o d u c t i v i t y i n th e W eddell Sea a lo n g th e edge o f th e p ack i c e , e x c e p t i n le a d s betw een p a c k i c e and s h e l f i c e n e a r th e c o n t i n e n t w here p r o d u c t i v i t y was h i g h . B ecause much o f th e W eddell Sea i s i c e cov e re d th r o u g h o u t th e y e a r and a l l o f i t f o r a b o u t n in e m onths o f th e y e a r (F ig u re 7)> e x p e d i ti o n s i n th e a r e a have g e n e r - . a l l y o c c u r r e d a t th e h e i g h t o f summer. L ig h t- a b s o r b in g i c e i s l e a s t w id e s p re a d th e n , and p r o d u c t i v i t y i s p ro b a b ly a t i t s a n n u a l maximum. I n some c a s e s , th e i c e i t s e l f may su p p o r t f l o u r i s h i n g d ia to m s (B u n t, 1963) , b u t th e s e d iato m s a re n o t a v a i l a b l e a s fo o d u n t i l th e i c e m e lts . Much o f th e m e ltin g d o e s n o t o c c u r u n t i l th e i c e h a s been t r a n s p o r t e d n o rth w a rd from th e W eddell Sea by s u r f a c e c u r r e n t s . A l though t h e r e i s l i t t l e d i r e c t e v id e n c e f o r low p r o d u c t i v i t y i n th e W eddell S e a , th e s c a r c i t y o f d iato m s and r a d l o l a r i a n s 231 i n th e W eddell Sea se d im e n ts i n d i r e c t l y s u g g e s ts low p ro d u c t i v i t y . A t r a n s i t i o n from d ia to m a c e o u s s e d im e n ts i n th e n o r th to n o n -d ia to m a c e o u s se d im e n ts i n t h e s o u th , a p p a r e n tly i d e n t i c a l to t h a t i n th e W eddell S e a , o c c u rs a t s i m i l a r l a t i tu d e s i n th e S outh A t l a n t i c ( P i r i e , 1913) and I n d ia n Ocean ( P h i l i p p i , 1910) s e c t o r s o f th e A n t a r c t i c . P re v io u s i n v e s t i g a t o r s have a c c e p te d o b s e r v a t i o n s o f d ia to m g ro w th i n pack i c e a r e a s a s p r o o f o f h ig h p r o d u c t i v i t y and have r e l i e d upon c u r r e n t s o r r a p i d s o l u t i o n o f s i l i c a a s an e x p la n a tio n o f th e " d is a p p e a ra n c e " o f f r u s t u l e s . P i r i e ( 1 9 1 3) r e j e c t e d d e t r l t a l d i l u t i o n a s w e ll a s low p r o d u c t i v i t y a s e x p la n a t i o n s b e c a u se th e se d im e n ts i n th e n o r th e r n p a r t o f th e a r e a w ith few d ia to m s w ere f a r rem oved from se d im e n t so u rc e a r e a s and c o n s i s t e d o f f i n e c l a y s . He t h e r e f o r e s u p p o rte d P h i l i p p i 's (1910) h y p o th e s is o f a c u r r e n t b e n e a th th e pack i c e c a r r y in g th e d ia to m s n o r t h . S u b seq u e n t work h a s p r o duced no e v id e n c e f o r t h i s c u r r e n t , b u t Deacon (E a rla n d , 1 9 3 6) b e li e v e d s c o u r b y c u r r e n t s i n th e b o tto m w a te r c o u ld remove th e d ia to m s . E a rla n d c o r r e c t l y p o i n te d o u t , how ever, t h a t b o tto m c u r r e n t s rem oving d ia to m s would a ls o p r e v e n t d e p o s i ti o n o f th e c la y s and f i n e s i l t s t h a t a re c h a r a c t e r i s t i c o f th e b o tto m d e p o s i t s . Clowes (1 9 3 8 ), p r e s e n t i n g a n o th e r h y p o t h e s is , p ro p o se d t h a t sudden c h an g es o f tem p era t u r e , v e r t i c a l c i r c u l a t i o n , and o t h e r f a c t o r s o p e r a t iv e n e a r th e A n t a r c t i c C onvergence c a u se d mass m o r t a l i t y o f d iato m s i n t h a t a r e a , w h ile n e a r th e p a c k i c e , m o r t a l i t y was p r i m a r i l y due to g r a z i n g z o o p la n k to n . D iatom o o z e , t h e n , w ould b e an a c c u m u la tio n o f f r u s t u l e s r e s i s t a n t to d i s s o l u t i o n b e c a u s e th e y haive n o t p a s s e d th r o u g h th e d i g e s t i v e s y s te m s o f h e r b i v o r e s . C low es' h y p o t h e s is d o e s n o t a d e q u a te ly e x p l a i n . t h e d i s t r i b u t i o n o f d ia to m a c e o u s s e d im e n ts , h o w e v er, b e c a u s e su c h s e d im e n ts o c c u r f a r s o u th o f th e A n t a r c t i c C o n v erg en ce i n a r e a s w here t h e r e a r e no r a p i d te m p e r a tu re c h a n g e s o r m arked v e r t i c a l c i r c u l a t i o n . S in c e th e n o n -d ia to m a c e o u s se d im e n ts i n t h e W ed d ell S ea c o n t a i n 'i m p o v e r i s h e d r a d i o l a r i a n a s s e m b la g e s th e c h a r a c t e r o f w hich can p o s s i b l y b e e x p la in e d b y low p r im a r y p r o d u c t i v i t y , i t i s s u g g e s te d t h a t th e o b s e r v a t i o n s o f f l o u r i s h i n g d ia to m s i n i c e e i t h e r do n o t a p p ly to th e n o r t h - c e n t r a l W ed d ell Sea o r g i v e a m is le a d in g I m p r e s s io n o f t h e a n n u a l p r o d u c t i o n o f d ia to m s . SUMMARY AND CONCLUSIONS 1. T o ta l ( l i v e p l u s dead) f o r a m i n i f e r a l a sse m b la g es on th e n o r th e r n S c o t ia R idge from 330 to a b o u t 3^00 m e te rs a r e p r e d o m in a n tly p l a n k t o n i c s and c a lc a r e o u s b e n th o n ic s . At s i m i l a r and g r e a t e r d e p th s on th e s o u th e r n and e a s t e r n Sco t i a R idg e and on th e a b y s s a l f l o o r s o f th e S c o tia and n o r t h e rn W eddell S e a s , t o t a l f o r a m i n i f e r a l a sse m b la g e s a re p r e d o m in a n tly a g g l u t i n a t e d b e n th o n ic s . In some o f th e assem b la g e s from 260 to 2350 m e te rs on th e s o u th e rn and e a s t e r n S c o t ia R id g e , th e l i v i n g a sse m b la g e s a re d o m in ated by c a l c a re o u s f o r a m i n i f e r a . A t g r e a t e r d e p th s , how ever, th e l i v in g a sse m b la g e s a r e u s u a l l y do m inated by a g g l u t i n a t e d f o r a m i n i f e r a . 2 . In p a r t , p o st-m o rte m d i s s o l u t i o n c a u s e s .t h e r a r i t y o f em pty c a lc a r e o u s f o r a m i n i f e r a l s k e l e t o n s i n t h e s o u th e rn and deep r e g io n s o f th e a r e a . The f a c t o f s o l u t i o n i s d e m o n s tra te d by s e v e r e l y c o rro d e d c a lc a r e o u s sp ecim ens w hich o c c u r i n sam ples from th ro u g h o u t th e a r e a . The r a t e o f s o l u t i o n h a s been q u a l i t a t i v e l y e s tim a te d from th e r a t i o o f l i v i n g to t o t a l c a l c a r e o u s sp ecim en s uBing th e same r a t i o f o r a g g l u t i n a t e d sp ecim en s a s a s ta n d a r d . A v e ry h ig h r a t i o f o r c a lc a r e o u s sp ecim en s from an assem b lag e i n w hich th e 233 234 r a t i o f o r a g g lu t i n a t e d specim ens i s low i n d i c a t e s a h ig h r a t e o f s o l u t io n o f c alciu m c a r b o n a te . Such a d is c r e p a n c y betw een l i v e : t o t a l r a t i o s f o r c a lc a r e o u s and n o n -c a lc a re o u s specim ens e x i s t s i n sam ples from th e s o u th e r n and d e e p e r p a r t s o f th e a r e a w here, i n many c a s e s , more th a n h a l f o f th e c a lc a r e o u s specim ens c o n ta in p ro to p la s m . L i v e : t o t a l r a t i o s i n fo u r sam ples from th e n o r t h e r n S c o tia R id g e, how e v e r , do n o t su g g e st d i f f e r e n t i a l d e s t r u c t i o n o f c a lc a r e o u s b e n th o n ic s i n t h a t a re a a lth o u g h p l a n k t o n i c specim ens i n th e same sam ples a re d e e p ly c o rro d e d .. 3. The fo re g o in g s u g g e s ts t h a t th e c a rb o n a te compen s a t i o n d e p th w hich i s d e e p e r th a n 4000 m e te rs i n a r e a s J u s t n o r th o f th e A n ta r c tic Convergence (Hough, 1956) r i s e s w ith I n c r e a s in g l a t i t u d e Bouth o f th e co n v erg en c e to 3400 m e te rs i n th e a r e a o f th e n o r th e r n S c o tia R idge and to a v e ry s h a l low d ep th i n th e a r e a o f th e s o u th e rn and e a s t e r n S c o tia R id g e. The c a rb o n a te com pen sation d e p th i n th e a r e a o f th e s o u th e rn and e a s t e r n S c o tia Ridge i s p ro b a b ly no d e e p e r th an 500 m e te rs , b u t th e r e a re to o few s h a llo w sam ples, from t h a t a r e a to a d e q u a te ly d e fin e i t . C o n d itio n s a lo n g th e s o u th e rn and e a s t e r n Scoti.a R idge, t h e r e f o r e , a r e l i k e th o s e i n th e R oss Sea where th e c a rb o n a te co m p en satio n d e p th i s a ls o v e ry sh a llo w (K e n n e tt, 1966) and u n l ik e th o s e i n some o t h e r a r e a s o f th e A n ta r c tic Ocean from w hich c a lc a r e o u s fo ra m i n i f e r a l a ssem b lag es have been d e s c r ib e d from d e p th s o f 2000 m e te rs and more (U chio, 1960b j Pflum , 1 9 6 6) . 4 . S u b s u rfa c e o c c u r r e n c e s o f c a lc a r e o u s a sse m b la g e s In th e n o r t h e r n W eddell Sea s u g g e s t t h a t a t some tim e In th e p a s t th e c a rb o n a te c o m p en satio n d e p th was d e e p e r th an 3000 m e te r s . F iv e s u r f a c e c a lc a r e o u s a sse m b la g e s from t h i s a r e a a r e p r o b a b ly e x p o s u re s o f th e s e o l d e r s t r a t a . These o c c u r r e n c e s c o n ta in m o n o s p e c ific p o p u l a t i o n s o f G lo b lg e r ln a pachyderm a i n w hich th e p r o p o r t io n o f l a r g e specim ens i s h ig h and th e p r o p o r t io n o f d e x t r a l l y - c o i l e d specim ens i s s l i g h t l y g r e a t e r th a n now found j u s t s o u th o f th e A n t a r c t ic C o n v erg en ce. T hese p e c u l i a r i t i e s a r e b e li e v e d to i n d i c a t e t h a t a t th e tim e th e c a lc a r e o u s a sse m b la g e s were d e p o s ite d t h e W eddell Sea s u r f a c e w a te rs were v e ry c o ld and p o s s i b l y i c e - c o v e r e d a s th e y a re now. A d d itio n a l s t u d i e s o f p la n k - * t o n i c f o r a m i n i f e r a l a sse m b la g e s n e a r th e c o a s t o f A n t a r c t ic a a r e n eeded to t e s t t h i s h y p o t h e s is . 5 . D i s t r i b u t i o n s o f c a lc a r e o u s and a g g l u t i n a t e d f o - r a m i n l f e r a w ere s t u d i e d s e p a r a t e l y . C a lc a re o u s f o r a m i n if e r a l fa u n a s on th e n o r th e r n S c o tia R idge s o u th o f S outh G e o rg ia I s l a n d d i f f e r from th o s e on th e s o u th e rn and e a s t e r n S c o t i a R id g e . Two f a u n a s , one o c c u r r in g d e e p e r th a n th e o t h e r , a re fou nd i n b o th a r e a s . These faunaB and th e domi n a n t s p e c ie s i n e a c h a r e : 236 S o u th G e o rg ia S lo p e U pper B a th y a l F auna (3 3 0 -7 5 0 m) A n g u lo g e rin a e a r l a n d i A s tro n o n io n e c h o l s i B u lim ln a a c u l e a t a C a s s i d u l i n o i d e s p a r k e r i a n u s F u r s e n k o in a f u s i f o r m i s T r a n s i t i o n a l Fauna (1030 m) D om inant s p e c i e s o f b o th u p p e r b a t h y a l and deep f a u n a s p r e s e n t Deep Fauna ( d e e p e r th a n 1500 m) E i l o h e d r a w e d d e l l e n s is G y r o id in a s u b p l a n u l a t a N o n io n e lla i r i d e a S o u th e rn an d E a s t e r n S c o t i a R idge B a th y a l F auna (3 7 0 -1 6 0 0 m) E i l o h e d r a w e d d e l l e n s is " E p i s t o m i n e l l a e x ig u a F u r s e n k o in a e a r l a n d i Deep Fauna (d e e p e r th a n 1600 m) E p o n id e s tu m id u lu s M e lo n is c f . M. a f f i n i s The f i v e s p e c i e s o f t h e u p p e r b a t h y a l fa u n a o f th e S o u th G e o rg ia s lo p e a r e uncommon on th e s l o p e s o f th e s o u t h e r n and e a s t e r n S c o t i a R id g e . E i l o h e d r a w e d d e l l e n s i s , com mon o n ly below 1000 m e te r s on th e S o u th G e o rg ia s lo p e , 1 b common a t 490 m e te r s an d d e e p e r on th e s l o p e s o f t h e s o u t h e r n and e a s t e r n S c o t i a R id g e . T hese d i f f e r e n c e s i n c a l c a r e 237 o u s a s s e m b la g e s a p p e a r r e l a t e d to d i f f e r e n c e s betw een t h e w a te r m asses o f th e two a r e a s . The u p p e r s lo p e f a u n a l zone s o u th o f S o u th G e o rg ia I s a s s o c i a t e d w ith th e te m p e r a tu r e maximum s tr a tu m o f th e Warm Deep L a y e r. B ecause o f m ix in g w ith c o l d e r s u r f a c e an d b o tto m w a te r s , t h i s l a y e r i s much d e p l e t e d a lo n g t h e s o u th e r n and e a s t e r n S c o t ia R id g e . The p o t e n t i a l te m p e r a tu re and s a l i n i t y c h a r a c t e r i s t i c s o f w a te r a t 600 m e te r s on th e s lo p e s o f th e s o u th e rn and e a s t e r n S c o t i a R id g e a r e s i m i l a r to th o s e o f w a te r below 1000 m e te r s on t h e s lo p e s o u th o f S o u th G e o rg ia . 6 . The a g g l u t i n a t e d s p e c i e s have been s e p a r a t e d i n t o a b a t h y a l g ro u p , an a b y s s a l g ro u p , and a n o n - d e f i n i t i v e g ro u p . The b a t h y a l g ro u p o f s p e c i e s i s i n s i g n i f i c a n t i n m ost a s s e m b la g e s below 2200 m e te rs and th e a b y s s a l g ro u p a r e i n s i g n i f i c a n t i n sam p les from above 1300 m e te r s . I n m ost sa m p le s t h e n o n - d e f i n i t i v e g ro u p c o m p rise s l e s s th a n 50 p e r c e n t o f th e a g g l u t i n a t e d f o r a m i n i f e r a . The m ost a b u n d a n t s p e c i e s i n t h e b a t h y a l and n o n - d e f i n i t i v e g ro u p s and s e l e c t e d d o m in a n ts from th e a b y s s a l g ro u p a r e : B a th y a l Group A m m o flln tin a a r g e n te a C rib ro s to m o id e s a re n a c e a M iliam m ina a re n a c e a M iliam m lna l a t a P o rta tro c h a m m in a a n t a r c t i c a P o rta tro c h a m m ln a w ie s n e r i P s e u d o b o liv ln a a n t a r c t i c a 238 A b y s s a l Group A m m om arginullna e n s l s C r ib r o s to m o id e s s p h a e r l l o c u i u s C rib r o s to m o id e s s u b g lo b o s u s E g g e r e l l a p a r k e r a e v a r . B G lo m o sp ira c h a r o ld e s M a r t i n o t t i e l l a a n t a r c t i c a Saccammina t u b u l a t a T r i t a x i s i n h a e r e n s N o n - d e f l n l t l v e Group A d erco try m a g lo m eratu m C onotrocham m ina b u l l a t a H ap lo p h rag m o Id es p a r k e r s e P o rta tro c h a m m in a e l t a n l n a e Trochammina q u a d r lc a m e r a ta 7 . Prom th e u p p e r and lo w e r d e p th l i m i t s o f a b u n d an t and p e r s i s t e n t a g g l u t i n a t e d s p e c i e s , se v e n d e p th b o u n d a r ie s a re s u g g e s te d o c c u r r i n g a t 2 6 0 -5 6 0 m, 1 2 0 0 -1 3 0 0 m, 2100- 23O O m, 2800-3100 m, 3100-3200 m, 35OO-37OO m, and 4 400- 4700 m. The b o u n d a ry a t 2100-2300 m e te rs i s th e m ost s i g n i f i c a n t . I t i s d e f in e d b y th e f i r s t o c c u r r e n c e s o f s i x s p e c i e s and th e f i r s t o f th e c o n s i s t e n t o c c u r r e n c e s o f f i v e o t h e r s p e c i e s . 8 . B e n th o n ic f o r a m i n i f e r a l b i o t o p e s o c c u r on th e a b y s s a l f l o o r s o f t h e S c o t ia and W eddell S e a s a s s o c i a t e d w ith d i s t i n c t i v e e n v ir o n m e n ta l c o m p lex e s. I n t h e E a s t S c o t ia B a sin and T ren ch Rim b i o t o p e s th e d ia to m c o n te n t o f s e d i m ents i s h ig h . The s e d im e n ts o f th e T ren ch Rim b i o to p e a r e l a r g e l y v o l c a n ic d e b r i s and d e p th s a r e g r e a t e r th a n th o s e o f th e EaBt S c o t i a BaBln b i o t o p e . In t h e P e r i p h e r a l W eddell 239 Sea b io to p e and th e C e n tr a l W eddell Sea b i o to p e , d ia to m s a r e r a r e o r v e ry r a r e In c la y s and s i l t y - c l a y s . The C e n tr a l W eddell Sea b io to p e i s more i s o l a t e d from th e p o s s i b l y more p r o d u c tiv e m arg in al- a r e a s o f th e W eddell S e a . D om inant s p e c i e s i n e ac h b io to p e a r e : E a s t S c o t ia B a sin B io to p e C rib ro s to m o id e s u m b il i c a tu l u s s o l d a n i i E g g e r e ll a p a r k e r a e v a r . B M a r t i n o t t i e l l a a n t a r c t i c a Reophax sp . A T rench Rim B io to p e A dercotrym a glom eratum G lom ospira c h a r o id e s T r i t a x i s In h a e r e n s P e r i p h e r a l W eddell Sea B io to p e Cyclammlna p u B i ll a C e n tr a l W eddell Sea B io to p e C rib ro s to m o id e s su b g lo b o su s 9. Conotrocham m ina k e n n e t t i and P o rtatro ch am m in a. e l - ta n i n a e dom inate b e n th o n ic f o r a m i n i f e r a l a sse m b la g e s o f v e ry low d i v e r s i t y i n th e u p p e r l e v e l s o f th e S outh Sandw ich T rench below s i l l l e v e l . No f o r a m in if e r a were fou n d i n th e d e e p e s t sam ple (7690 m ). As i n th e P e ru -C h ile T rench (Bandy and R o d o lfo , 1964) and i n th e u p p e r l e v e l s o f th e K u ril-K am ch atk a T rench (S h c h e d rin a , 1958), endem ic s p e c i e s 240 a r e r a r e i f th e y e x i s t a t a l l . U n lik e th e fo ram s o f o t h e r 'tr e n c h e s i n w h ich f o r a m i n i f e r a h a v e b een s t u d i e d , h ow ever, a l l f o r a m i n i f e r a l sp e c im e n s i n th e S o u th S andw ich T ren ch w ere s m a ll. 10. C e r t a i n d i s t i n c t i v e w a l l s o f a g g l u t i n a t e d f o r a m i n i f e r a have e c o l o g i c a l s i g n i f i c a n c e . N ine s p e c i e s o f t h e f a m ily A ta x o p h ra g m iid a e h a v in g a c a l c a r e o u s cem ent o c c u r c o n s i s t e n t l y i n a s s e m b la g e s d o m in a te d by c a l c a r e o u s b e n - th o n ic f o r a m i n i f e r a b u t r a r e l y i n a s s e m b la g e s d o m in a te d by o t h e r a g g l u t i n a t e d f o r a m i n i f e r a . S p e c ie s o f th e f a m i l i e s A ta x o p h ra g m iid a e (M a r t i n o t t i e l l a a n t a r c t i c a an d E g g e r e l l a p a r k e r a e v a r . B) and R z e h a d in id a e ( S p iro lo c a m m in a t e n u i s ) w h ich h av e w h ite w a l l s o c c u r c o n s i s t e n t l y i n s e d im e n ts h a v in g a h ig h d ia to m c o n te n t an d r a r e l y i n s e d im e n ts h a v in g few d ia to m s . T hese s p e c i e s w ith w h ite w a l l s p o s s i b l y h ave a s i l i c e o u s cem ent an d t h u s may r e q u i r e l a r g e q u a n t i t i e s o f d i s s o l v e d s i l i c a i n i n t e r s t i t i a l w a t e r s w hich w ould be p r o v id e d by a l a r g e d ia to m c o n t e n t . 11. A c lo s e tax o n o m ic r e l a t i o n s h i p e x i s t s betw een s p e c i e s w ith c a l c a r e o u s w a l l s and s p e c i e s w ith w h i t e , p o s s i b l y s i l i c e o u s , w a l l s i n th e f a m ily A ta x o p h ra g m iid a e . C lo se m o rp h o lo g ic p a r a l l e l s c o n fir m th e c o n g e n e ric s t a t u s o f M a r t i n o t t i e l l a m i l l e t t l w h ich h a s a c a l c a r e o u s cem ent and M. a n t a r c t i c a w hich p o s s i b l y h a s a s i l i c e o u s c em en t. A form o f E g g e r e l l a p a r k e r a e o c c u r s w ith a w h i t e , p o s s i b l y s i l i c e o u s , w a ll w ith an e x t e r n a l m o rp h o lo g y i d e n t i c a l to a fo rm w hich h a s a c a l c a r e o u s w a l l . The I n s o l u b l e w a l l a p 241 p e a r s to be an a d a p t a t i o n to an e n v iro n m e n t u n d e r s a t u r a t e d i n c a lc iu m c a r b o n a te . 12. Rem ains o f s i l i c e o u s p e l a g i c o rg a n is m s i n b o tto m s e d im e n ts i n d i c a t e a m arked n o r t h - s o u t h e n v ir o n m e n ta l g r a d i - . e n t i n t h e a r e a o f th e s o u th e r n S c o t i a R id g e . The s o u th e r n l i m i t o f s e d im e n ts h a v in g a b u n d a n t d ia to m s o c c u r s J u s t s o u th o f t h e S c o t i a R id g e , t h e r e b e in g v e ry few d ia to m s i n s e d i m ents o f th e n o r t h - c e n t r a l W eddell S e a . From th e S c o t i a Sea to th e W ed d ell S ea, c o n c u r r e n t w ith t h e t r a n s i t i o n from d i a - tom aceous to n o n -d ia to m a c e o u s s e d im e n ts , th e ab u n d an ce o f r a d i o l a r i a n s f a l l s from more th a n 1 0 ,0 0 0 to l e s s th a n 10 sp e cim en s p e r gram o f s e d im e n t, and th e c h a r a c t e r o f t h e r a d i o l a r i a n a sse m b la g e s c h an g e s m a rk e d ly . S p h e r i c a l r a d i o - l a r i a n s , p r i m a r i l y Spongoplegm a a n t a r c t i c u m , d o m in a tin g s p a r s e W eddell Sea r a d i o l a r i a n a s s e m b la g e s , a p p e a r to b.e s u r v i v o r s i n an e n v iro n m e n t m a rg in a l f o r r a d i o l a r i a n s . I t i s s u g g e s te d t h a t low p rim a r y p r o d u c tio n o f o r g a n i c m a t t e r , i n d i c a t e d by th e r a r i t y o f d ia to m s i n W ed dell Sea b o tto m s e d im e n ts , i s a p r i n c i p a l f a c t o r c a u s in g th e W ed d ell Sea to b e m a r g in a l f o r r a d i o l a r i a n s . SYSTEMATIC DESCRIPTIONS . One new g e n u s I s d e s c r i b e d a n d a n o t h e r g e n u s i s emended. F iv e new s p e c i e s a r e d e s c r i b e d a n d a s i x t h , o f e x c e p t i o n a l i n t e r e s t b e c a u s e i t a p p a r e n t l y s e c r e t e s a t e s t w a l l o f o p a l i n e s i l i c a , I s d e s c r i b e d b u t l e f t unnam ed p e n d in g f u r t h e r I n v e s t i g a t i o n o f t h e w a l l . S in c e t h e p u r p o s e o f t h i s s tu d y I s n o t p r i m a r i l y ta x o n o m ic , s p e c ie B t h a t o c c u r s p o r a d i c a l l y a t f r e q u e n c i e s o f l e s s th a n 3 p e r c e n t h a v e n o t b e e n named . a lt h o u g h t h e y a p p e a r t o h a v e no c o u n t e r p a r t s i n th e e x i s t i n g l i t e r a t u r e . To r e c o r d t h e i r o c c u r r e n c e I n t h e S c o t i a S ea a r e a m o st o f t h e s e r a r e s p e c i e s a r e i l l u s t r a t e d and th e o t h e r s a r e b r i e f l y d e s c r i b e d . As r e s e a r c h on A n t a r c t i c and d e e p - s e a F o r a m i n i f e r l d a c o n t i n u e s , a d d i t i o n a l sp e c im e n s o f t h e s e s p e c i e s w i l l u n d o u b te d ly be fo u n d p e r m i t t i n g a b e t t e r u n d e r s t a n d i n g o f them th a n I s p o s s i b l e w ith t h e m a t e r i a l o f t h i s s t u d y . The d e s c r i p t i o n s o f r a r e s p e c i e s an d r e f e r e n c e s to t h e f i g u r e s o f a l l i l l u s t r a t e d s p e c i e s a p p e a r i n t h e l i s t o f s p e c i e s t h a t f o l l o w s . 242 243 F a m ily RZEHAKINIDAE Cushman, 1933 Genus A m m o flin tin a E a r l a n d , 1934 A m m o flin tin a a r g e n t e a E c h o ls , n . sp . P l a t e I I , F ig u r e 7 D i a g n o s i s : T e s t f r e e , s m a l l , i r r e g u l a r l y p l a n i s p i r a l , ■ b i l a t e r a l l y c o m p re sse d , s u b t r i a n g u l a r to s u b q u a d r a te i n o u t l i n e , ed g e ro u n d e d ; ch am b ers few , c r e s c e n t - s h a p e d , t h r e e p e r w h o rl, l o c a t e d on e i t h e r B ide o f t h e m e d ia l p l a n e o f th e t e s t , b u t n o t r e g u l a r l y a l t e r n a t i n g ; g e n e r a l l y f o u r to f i v e cham bers v i s i b l e on one s i d e o f th e t e s t and t h r e e on t h e o t h e r s i d e ; s u t u r e s d e p r e s s e d , d i s t i n c t ; a p e r t u r e on o b s c u r e , e x c e n t r i c i n t e r i o m a r g i n a l s l i t ; w a l l a g g l u t i n a t e d , t h i n ; s u r f a c e u n e v e n ; c o l o r g r e y . H o lo ty p e : USNM No. 68 7 2 0 8 ; d i a m e t e r 0 .2 3 mm* t h i c k n e s s 0 .1 1 mm; from USC 6 5 9 . V a r i a t i o n : A m m o flin tin a a r g e n t e a i s c h a r a c t e r i z e d by c o n s i d e r a b l e i r r e g u l a r i t y i n cham ber a r r a n g e m e n t. A l th o u g h c o i l i n g i s p l a n i s p i r a l , t h e cham bers a r e n e v e r l o c a t e d s y m m e tr ic a lly to th e p l a n e o f c o i l i n g , an d s u c c e s s i v e cham bers may be on t h e same o r o p p o s i t e s i d e s o f t h e t e s t . B e ca u se s e p t a a r e n o t c l e a r l y v i s i b l e even i n sp e c im e n s c l a r i f i e d w ith o i l o f a n i s e , t h e i n t e r n a l cham ber a r r a n g e m ent i s u n c e r t a i n , b u t m ost s p e c im e n s a p p e a r to c o n s i s t o f no more th a n two w h o r ls . 244 O c c u r r e n c e : A m m o flin tin a a r g e n t e a o c c u r s a t 15 s t a t i o n s from d e p th s o f 560 t o 2640 m e te r s . I t i s m ost a b u n d a n t and p e r s i s t e n t i n t h e a r e a o f th e S o u th Sandw ich I s l a n d s and d id n o t o c c u r i n sa m p le s from t h e S o u th G e o rg ia s l o p e . 0 R e m a rk s: T h is s p e c i e s , w h ich i s u n l i k e any p r e v i o u s l y d e s c r i b e d f o r a m i n i f e r a n , i s p r o v i s i o n a l l y r e f e r r e d to t h e g e n u s A m m o flin tin a b e c a u s e i t h a s few c r e s c e n t sh ap ed cham - • i b e r s a r r a n g e d t h r e e i n a w h o rl a s d o e s A. t r l h e d r a E a r la n d , t h e ty p e s p e c ie B o f t h e g e n u s . The a p e r t u r e o f A. t r i h e d r a . h o w e v er, i s a c i r c u l a r o r s e m i c i r c u l a r o p e n in g o f th e d i s t a l en d o f th e l a s t c h am b er, w h e re a s t h e a p e r t u r e o f A. a r g e n t e a i s a v e ry s m a ll i n t e r i o m a r g i n a l s l i t . Genus Oystammina Neumayr, l889.» emended E chols P la te I I , F ig u re s 8 , 9 Oystammina Neumayr, 1889, Die Stamme des T h ie rre ic h e s ; w ir b e llo B e t h i e r e , v . 1, p . 1 6 7 . Ammo c h i l o s tom e1l a E lm er and F i c k e r t , 1899> Z e l t s c h r . W iss. Z o o l , , v. 6 5 , p t . 4 , p . 6 9 2 . Type s p e c i e s : Trocham m ina p a u c l l o o u l a t a B ra d y , 1 8 7 9, s u b s e q u e n t d e s i g n a t i o n , G a llo w ay , 1933. Emended d i a g n o s i s b a s e d on A n t a r c t i c m a t e r i a l : T e s t f r e e ; w a l l a g g l u t i n a t e d ; c o i l i n g m l l l o l l n e w ith a p e r t u r e s o f e a c h s u c c e e d in g cham ber a l t e r n a t i n g a t e i t h e r p o le o f a 245 s h o r t a x is o f th e t e s t ; cham bers added n e a r l y i n a p la n e aro u n d t h i s a x is a t more th a n 120 d e g r e e s , b u t l e s s th a n 180 d e g re e s from th e p r e c e d in g cham ber; cham bers g lo b o se and e lo n g a te d p e r p e n d i c u l a r to th e c o i l i n g a x i s , i n c r e a s i n g r a p i d l y i n s i z e a s added; t h r e e cham bers ex p o sed a ro u n d th e p e r im e te r o f th e t e s t ; t h r e e e x p o sed on th e a b o r a l s i d e , b u t o f t e n f o u r on th e o r a l s i d e ; a p e r t u r e a r e a l , o v a te i n y o u n g e r sp e c im e n s, l a t e r s l i t - l i k e , l o c a te d n e a r th e s u t u r e . D is c u s s io n : The emended d i a g n o s is i s b a s e d on A n ta rc t i c m a t e r i a l o f Cvstamm ina p a u c i l o c u l a t a . th e d i s t i n c t i v e and c o s m o p o lita n , d e e p -w a te r ty p e o f th e g e n u s. T h is s p e c i e s b e a r s a s u p e r f i c i a l re s e m b la n c e to th e h y a lin e g e n u s A llo m o rp h in a w hich p r o b a b ly le a d B rady to assum e t h a t th e c o i l i n g was t r o c h o s p i r a l w ith l a t e r cham bers encom pass in g much o f th e e a r l i e r t e s t and c o n c e a lin g th e s p i r e , an i n t e r p r e t a t i o n a c c e p te d by l a t e r a u t h o r s . As shown i n P l a t e I I , F ig u r e s 8a and b , h ow ev er, a p e r t u r e s a l t e r n a t e on e i t h e r s id e o f th e t e s t and th e cham ber a rra n g e m e n t i s m i- l i o l i n e . The g e n u s , t h e r e f o r e , i s h e r e i n emended and t r a n s f e r r e d from th e Trocham m inidae to th e R z e h a k ln ld a e . Family TROCHAMMINIDAE Schwager, 1877 Genus Conotrochammina F in la y , 1940 Conotrochammina k e n n e tti Echols, n . sp. P la te VI, F ig u re 1 D ia g n o s is : T e s t f r e e , s m a ll, t r o c h o s p i r a l , s u b c o n lc a l 246 o r g lo b o s e ; p e r i m e t e r l o b u l a t e ; u p to t h r e e w h o rls e x p o s e d on th e d o r s a l s u r f a c e w hich i s domed o r f l a t i n th e a r e a o f th e e a r l y w h o rls s u c h t h a t t h e g lo b o s e t e s t a p p e a r s t r u n c a t e d ; f o u r to s i x ch am b ers i n t h e e a r l i e s t w h o rl; o n l y t h e f o u r h i g h l y - i n f l a t e d cham bers o f th e l a s t w h o rl v i s i b l e on th e v e n t r a l s i d e ; s u t u r e s d e p r e s s e d and som ewhat c u rv e d on t h e d o r s a l s i d e , d e e p ly d e p r e s s e d on th e v e n t r a l s i d e ; a p e r t u r e a s m a ll a r e a l s l i t f a c i n g th e u m b il i c u s ; w a l l c o a r s e l y a r e n a c e o u s , com posed o f a w ide v a r i e t y o f p a r t i c l e s i z e s , r o u g h ly f i n i s h e d . D ia m e te r o f l a r g e s t sp e c im e n s a b o u t 0 .2 7 mm. H o lo ty p e : USNM No. 687209; d ia m e te r 0 .1 6 mm, t h i c k n e s s 0 .1 5 mm; from USC 6 3 8 . V a r i a t i o n : C onotrocham m lna k e n n e t t i shows a w ide r a n g e o f v a r i a t i o n . Some im m ature s p e c im e n s , com posed o f two w h o r ls , a r e s m a ll and q u a d r a t e w ith a domed u p p e r s u r f a c e and a s h a llo w u m b i l i c u s . O th e rs o f th e same s i z e h a v e f i v e o r s i x ch am b ers p e r w h o rl, a f l a t d o rB a l s u r f a c e , a n d a n a rro w d eep u m b i l i c u s . I n th e l a r g e s t sp e c im e n s , t h e l a s t o n e o r two ch am b ers a r e u s u a l l y add ed i n an I r r e g u l a r man n e r a c r o s s th e u m b i l i c u s . L a rg e r cham bers a r e s t r u c t u r a l l y weak and e a s i l y b ro k e n i n h a n d lin g ; c o m p le te l a r g e s p e c i mens a r e t h e r e f o r e r a r e * O c c u r r e n c e : C onotrocham m ina k e n n e t t i o c c u r s i n 20 sa m p le s from th e S c o t i a and n o r t h e r n W ed d ell S e a s , a l l fro m 247 b elo w 2700 m e te r s , b u t i s a b u n d a n t o n l y i n th e S o u th Sand w ic h T ren ch belo w 5500 m e te r s w here i t c o m p ris e s 24 p e r c e n t o f th e f o r a m i n i f e r a i n e a c h o f two s a m p le s (USC 6 3 8 , USC 6 4 6 ) . C o m p ariso n : Most sp e c im e n s o f £ . k e n n e t t i a r e w i t h in t h e ra n g e o f v a r i a t i o n o f C. b u l l a t a (H oglund) i n a l l c h a r a c t e r i s t i c s e x c e p t w a l l t e x t u r e . The w a l l o f C _. b u l l a t a i s sm o o th e r, com posed o f f i n e r p a r t i c l e B , and i s u s u a l l y a l m o st p o l i s h e d . O c c a s io n a l l a r g e r p a r t i c l e s u s e d by t h i s s p e c i e s a r e s e t i n th e f i n e r m a t r ix an d g e n e r a l l y p r o t r u d e l i t t l e from th e s u r f a c e o f t h e t e s t . In c o n t r a s t , th e w a l l o f C.. k e n n e t t i i s d o m in a n tly com posed o f l a r g e r p a r t i c l e s , u p to 0 .0 4 mm i n d i a m e t e r ; t h e s u r f a c e i s v e r y ro u g h and n e v e r p o l i s h e d . At th e 14 s t a t i o n s w here t h e s e two s p e c i e s o c c u r t o g e t h e r , th e y a r e e a s i l y d i s t i n g u i s h e d b y w a l l t e x t u r e and do n o t I n t e r g r a d e . Name: T h is s p e c i e s i s named f o r D r. J . P. K e n n e tt. Genus P o rta tro c h a m m ln a , new g e n u 8 Type s p e c i e s : P o rta tro c h a m m ln a e l t a n i n a e E c h o ls , n . s p . D i a g n o s i s : T e s t f r e e , t r o c h o s p i r a l , e x p a n d in g g r a d u a l l y ; w a l l a g g l u t i n a t e d ; p r o l o c u l u s t e c t i n o u s ; d o r s a l s i d e f l a t to m o d e r a te ly c o n v e x ; v e n t r a l s i d e co n v ex ; u m b il i c u s c o v e re d by a s e r i e s o f o v e r l a p p in g f l a p s , one f l a p d e r i v e d from e a c h cham ber; u m b i l i c a l f l a p d i s t i n g u i s h e d from th e 248 cham ber by f l a t t e r c o n to u r and o f t e n b y f i n e r a g g l u t i n a t i o n ; f l a p o f f i n a l cham ber u s u a l l y c o m p le te ly c o v e r in g u m b ilic u s c o n c e a lin g f l a p o f p e n u ltim a te cham ber; a p e r t u r e a low i n - t e r i o - m a r g i n a l a r c h i n th e l a s t s e p t a l fa c e c o n tin u in g a s a s l i t a ro u n d th e e n t i r e f r e e edge o f th e f l a p . D i s c u s s io n : T h is g enus m ost c l o s e l y r e s e m b le s S ip h o - trocham m lna S a u n d e rs , a form from th e m angrove swamps o f T r in id a d . S au n d e rs (1957* P . 9) d e s c r i b e s th e m o d ifie d u m b i l i c a l p a r t o f th e cham ber o f S lpho trocham m ina a s , "a v e n t r a l , s i p h o n l ik e lo b e e x te n d in g p a r t i a l l y a c r o s s th e u m b il i c u s ." I t was p o s s i b l e to exam ine th e g e n o h o lo ty p e ' and f i g u r e d p a ra ty p e o f S iphotrocham m ina l o b a t a w hich a r e d e p o s ite d i n th e U .S . N a tio n a l Museum. I n th e s e two s p e c i m ens, th e u m b i l i c a l ends o f th e cham bers a r e m o d ifie d i n t o t r i a n g u l a r lo b e s w hich p a r t i a l l y o v e r la p i n th e U m b ilic u s . LobeB o f a l l cham bers i n th e l a s t w h o rl a r e v i s i b l e ; th e t r a i l i n g edge o f th e l a s t lo b e i s a t t a c h e d to th e lo b e o f th e p e n u ltim a te cham ber, and th e a p e r t u r e i s a s e m i c i r c u l a r o p e n in g b e n e a th th e le a d in g edge o f th e lo b e . P o rta tro o h a m - mina d i f f e r s from S iphotrocham m ina i n t h a t th e f l a p s c o n s i s t e n t l y c o v e r th e u m b ilic u s and c o n c e a l, o r n e a r l y c o n c e a l, th e f l a p s o f th e p re c e d in g cham b ers. T h is p ro d u c e s a la m i n a te d s t r u c t u r e f i l l i n g th e u m b ilic u s , th e f l a p o f e ach cham ber ad d in g one la m in a . The u m b i l i c a l f l a p s o f P o r t a t r o chammlna a r e t h e r e f o r e a n a lo g o u s to th o s e o f t h e h y a li n e 249 g e n u s V a l v u l i n e r i a . I n c o n t r a s t to th e a p e r t u r e o f S ip h o - * tro ch am m in a, th e a p e r t u r e o f P o rta tro c h a m m ln a e x te n d s com p l e t e l y a ro u n d th e f r e e edge o f th e f l a p , o c c a s i o n a l l y b e in g somewhat e n la r g e d on th e l e a d in g e d g e . T rocham m inula f l s s l p e r t a S c h e d r in a , th e g e n o ty p e o f T rocham m inula S c h e d r in a , p o s s e s s e s cham ber lo b e s w hich e x te n d a cro sB th e u m b i l i c u s , b u t i t s s l i t - l i k e a p e r t u r e e x te n d in g i n t o th e a p e r t u r a l f a c e d i s t i n g u i s h e s t h i s g enu s from P o r ta tro c h a m m ln a . P o rta tro c h a m m ln a e l t a n i n a e E c h o ls , n . s p . P l a t e V I I I , F ig u r e s 1, 2 Trochammina i n f l a t a , E a r la n d ( n o t M ontagu, 1 8 0 8 ), 193^* D is c o v e ry R e p ts .> v . 10, p . 99, p i , 3 , f i g s . 4 l- 4 3 D i a g n o s i s : T e s t f r e e , s m a ll , t r o c h o s p i r a l , com pact; p e r i m e t e r m o d e r a te ly l o b u l a t e ; edge e v e n ly ro u n d e d ; d o r s a l s id e f l a t to m o d e r a te ly h i g h - s p i r e d ; v e n t r a l s i d e conv ex, th e u m b ilic u s c o v e re d by a f l a p d e r i v e d from th e l a s t s e p t a l f a c e ; t e s t com posed o f two and a h a l f o r t h r e e w h o rls , f o u r and a h a l f to f i v e cham bers i n e ac h w h o rl; cham bers c l o s e l y a p p r e s s e d , s u b s p h e r i c a l , i n c r e a s i n g g r a d u a l l y i n s i z e ; b u - t u r e s r a d i a l , d e p r e s s e d and s l i g h t l y c u rv e d on th e d o r s a l s i d e , d e e p ly d e p r e s s e d and s t r a i g h t on th e v e n t r a l s i d e , u s u a l l y d i s t i n c t b u t d e t a i l s may be c o m p le te ly o b s c u re d i n e a r l i e r w horlB o f more g r a n u l a r t e s t s ; u m b i l i c a l end o f e ac h cham ber m o d ifie d i n t o f l a p o f g e n t l y convex c u r v a tu r e 250 and f i n e r a g g l u t i n a t i o n th a n th e re m a in d e r o f th e t e s t , e ac h f l a p c o v e rin g u m b ilic u s and c o n c e a lin g f l a p s o f e a r l i e r cham bers; a p e r t u r e open a ro u n d f r e e edge o f f l a p , su p p le m e n te d by a sm a ll a rc h e d o p e n in g J u s t i n s i d e o r J u s t o u t s id e th e c o r n e r o f th e f l a p a t th e b a s e o f th e l a s t s e p t a l f a c e i n a few sp ecim en s; w a ll t h i n , g r a n u l a r to s u b - l a e v i - g a t e , composed o f m in e ra l g r a i n s up to 0 .0 2 mm i n d ia m e te r s e t sm o o th ly i n a f i n e r groundm ass; p r o l o c u l u s t e c t i n o u s , la c k in g a g g l u t i n a t e d p a r t i c l e s ; c o l o r l i g h t brown to medium brow n. L a rg e r specim ens i n a sse m b la g e s ra n g e i n d ia m e te r from 0 .1 8 to 0 ,2 3 mm. R a tio o f w id th o f t e s t to h e ig h t o f l a s t cham ber from 1 .6 to 2 . 0 . H o lo ty p e : ( P l a t e V I I I , F ig u re l ) USNM No. 687210; maximum d ia m e te r 0 .2 8 mm,> th ic k n e s s 0 .1 7 mm; from USC 5 0 3 . F ig u re d p a r a t y p e : ( P l a t e V I I I , F ig u re 2) USNM No. 6 8 7 2 1 1; maximum d ia m e te r 0 .2 0 mm, t h i c k n e s s 0 .1 2 mm; from USC 6 3 8 . V a r i a t i o n : The g r e a t e s t v a r i a b i l i t y o f t h i s s p e c i e s i s i n th e h e ig h t o f th e s p i r e and t h e c o a r s e n e s s o f a g g l u t i n a t i o n ; th e ra n g e o f v a r i a t i o n commonly e n c o u n te re d i s shown by th e h o lo ty p e and f i g u r e d p a r a t y p e . The h o lo ty p e i s f l a t on th e d o r s a l s id e and r e l a t i v e l y c o a r s e l y a re n a c e o u s ; th e p a r a ty p e i s h i g h - s p i r e d and B u b - la e v ig a te . Such v a r i a t i o n i n th e h e ig h t o f s p i r e i s found i n m ost sam pleB . C o a rse n e ss 251 o f a g g l u t i n a t i o n seem s r e l a t e d to t h e q u a n t i t y o f medium s i l t a v a i l a b l e i n th e sa m p le , b u t d i r e c t c o m p a riso n w ith , s e d im e n t t e x t u r e d a ta i s n o t i l l u m i n a t i n g b e c a u s e o f th e p r e p o n d e r a n c e o f s i l i c e o u s b i o g e n i c m a t e r i a l i n th e s i l t f r a c t i o n o f many s a m p le s . O c c u r r e n c e : P o rta tro c h a m m ln a e l t a n i n a e i s one o f th e - m o s t common s p e c i e s i n th e sa m p le s o f t h i s s t u d y . I t s s h a l l o w e s t o c c u r r e n c e i s a t 490 m e te r s i n sa m p le s from n e a r th e S o u th O rkney I s l a n d s ; i t i s p r e s e n t i n a l l sa m p le s from n e a r th e S o u th S andw ich I s l a n d s , th e s h a l l o w e s t o f w h ich i s 558 m e t e r s . In sa m p le s from th e S o u th G e o rg ia I n s u l a r s l o p e , h o w e v er, i t i s n o t fo u n d s h a l lo w e r th a n 1500 m e te r s . I n t h e t h r e e s a m p le s from th e u p p e r l e v e l s o f th e S o u th Sandw ich T re n c h , I t I s 3 6 , 4 l , and 54 p e r c e n t o f th e fo ram - i n i f e r a l a s s e m b la g e s . C o m p a riso n : P o rta tro c h a m m ln a e l t a n i n a e i s m ost s i m i l a r to t h e two o t h e r s p e c i e s o f t h e g e n u s w h ich o c c u r i n th e S c o t i a an d W e d d e ll S e a s . I t d i f f e r s from P. a n t a r c t i c a ( P a r r ) ( P l a t e V I I , F i g u r e s 4 -7 ) i n t h a t t h e l a s t s e p t a l f a c e i s e v e n ly ro u n d e d i n edge view r a t h e r th a n rho m b o id , a n d i n i t s s m a l l e r s i z e . S p ecim en s o f P. a n t a r c t i c a I n th e R o ss S e a , i t s ty p e a r e a , hav e cham bers w hich a r e m ore ro u n d e d th a n t h o s e i n sp e c im e n s from th e S c o t i a S ea, b u t ev en t h e r e a s u g g e s t i o n o f a rh o m b o id p r o f i l e can be seen i n t h e l a s t s e p t a l f a c e ( P l a t e V I I , F i g u r e s 5 ~ 7 ) . P o r t a - 252 trocham m ina w le s n e r l ( P a r r ) d i f f e r s In b e in g more c o m p re ss ed ( P l a t e V I I , F ig u r e s 1 - 3 ) . Trochammina .lap o n ica Ish iw a d a I s re m a rk a b ly s i m i l a r I n form , b u t d i f f e r s I n I t s l a r g e r s i z e (0 .3 8 mm), o b liq u e s u t u r e s , and s e m i c i r c u l a r a p e r t u r e . Genus Trochammina P a r k e r and J o n e s , 1859 Trochammina q u a d ric a m e ra ta E c h o ls , n . sp . P l a t e IV , F ig u re 4 D ia g n o s i s : T e s t f r e e , s m a ll, t r o c h o s p i r a l ; d o r s a l s p i r e low; v e n t r a l s i d e s l i g h t l y d e p re s s e d o r a lm o st p la n e ; p e r i m e t e r s l i g h t l y l o b u l a t e ; edge ro u n d ed ; cham bers s l i g h t l y i n f l a t e d , i n c r e a s i n g g r a d u a l l y i n s i z e ; up to th r e e and a h a l f w h o rls v i s i b l e on th e d o r s a l s i d e ; o n ly th e l a s t f o u r o r som etim es 5 cham bers v i s i b l e on th e v e n t r a l s i d e ; p r o - l o c u l u s d e p r e s s e d a l i t t l e below th e l e v e l o f th e f i r s t w h o rl i n some sp e cim en s; s u t u r e s s l i g h t l y d e p re s s e d , a l i t t l e c u rv e d and a lm o st r a d i a l on th e d o rB a l s id e and somewhat i n d i s t i n c t i n th e e a r l y p a r t o f th e t e s t , d i s t i n c t , r a d i a l , and m ee tin g a t n e a r r i g h t a n g le s on th e v e n t r a l s i d e ; a p e r t u r e a r e s t r i c t e d h ig h l n t e r l o m a r g l n a l a rc h n e a r th e p e r i m e t e r on th e v e n t r a l s i d e ; w a l l f i n e l y a re n a c e o u s , com posed o f g r a i n s o f n e a r l y e q u a l s i z e , n o t sm ooth, c o l o r l i g h t brow n. H o lo ty p e : USNM No. 687212; maximum d ia m e te r 0 .1 6 mm, t h i c k n e s s 0 .1 1 mm; from ELT 500. 253 R em arks: Some im m ature specim ens o f Trochammina quad- r ic a m e r a ta a r e f l a t d o r s a l l y and v e n t r a l l y and have an a p e r t u r e lo c a te d on th e p e r i m e t e r . T h is and th e s l i g h t l y de p r e s s e d p r o l o c u l u s s u g g e s ts r e l a t i o n s h i p to th e L itu o lid a e r a t h e r th a n to o t h e r s p e c ie s o f Trochamm ina. A c lo s e r e sem blance e x i s t s betw een t h i s s p e c ie s and some i r r e g u l a r l y c o il e d specim ens o f H aplophragm oides q u a d ra tu s E a rla n d in s i z e , g r o s s m orphology o f th e t e s t and a p e r t u r e , and w a ll t e x t u r e . E a r ly i n t h i s s tu d y , th e two s p e c ie s w ere co unted to g e t h e r and th u s th e y a re u n d i f f e r e n t i a t e d f o r some s t a t i o n s i n Table' 2. H aplophragm oides q m ad ratu s d i f f e r s from t h i s s p e c ie s i n b e in g i n v o l u t e , a t l e a s t i n th e e a r l y p a r t o f th e t e s t j i n th e p r o l o c u l u s w hich i s su rro u n d e d by th r e e r e l a t i v e l y l a r g e cham bers o f th e f i r s t w h o rl r a t h e r th an f o u r sm a ll cham bers, and i n th e a p e r t u r e w hich i s l e s s r e s t r i c t e d . O c c u rre n c e : Trochammina q u a d ric a m e ra ta i s an abundant and e u ry b a th y a l s p e c i e s (490 to 4490 m e te rs ) i n th e S c o tia and W eddell S e a s. "M l l i o l i n e l l a ” sp . P l a t e X I I , F ig u re 1 M i l l o l l n a l a b i o s a , E a rla n d (n o t T r i l o c u l l n a l a b l o s a d ’O rbig ny, 1B39) / 1934, D isc o v e ry R e p t., v . 10, p . 50, p i . I , f i g u r e s 5 -7 D ia g n o s is : T e s t f r e e , s m a ll, s t o u t , o v a te i n s id e and a p e r t u r a l v iew s; cham bers la g e n ifo rm c o n s i s t i n g o f a hem i s p h e r i c a l p a r t f o llo w e d b y a t u b u l a r p a r t l e a d i n g to t h e a p e r t u r e ; c o i l i n g a lm o s t p l a n i s p i r a l w ith e a c h cham b er a d d e d m ore th a n 180 d e g r e e s a ro u n d t h e p e r i m e t e r o f t h e t e s t fro m t h e p r e c e d i n g c h am b er; t h r e e ch am b ers e x p o se d a ro u n d th e p e r i m e t e r o f t h e t e s t * a s m a ll p a r t o f a f o u r t h cham ber e x p o s e d on one s i d e ; s u c c e s s i v e c h am b ers i n c r e a s i n g r a p i d l y i n s i z e su c h t h a t t h e s u r f a c e a r e a o f th e l a s t cham ber com p o s e s a b o u t o n e - h a l f o f th e s u r f a c e a r e a o f t h e t e s t ; s u t u r e s a lm o s t f l u s h , i n d i s t i n c t ; a p e r t u r e s m a l l , s e m i c i r c u l a r , p a r t i a l l y c l o s e d b y a b r o a d f l a p ; w a l l w h ite a n d o p a q u e when d r y , t r a n s p a r e n t when w e t, i n s o l u b l e i n d i l u t e h y d r o c h l o r i c a c i d , l a c k i n g a p p a r e n t a g g l u t i n a t e d p a r t i c l e s , p o s s i b l y com posed o f o p a l i n e s i l i c a . Maximum l e n g t h o f f i g u r e d sp e c im e n 0 .4 0 mm; w id th 0 .2 4 mm; t h i c k n e s s 0 * 2 2 mm. O c c u r r e n c e : O nly 31 sp e c im e n s o f t h i s s p e c i e s a t 20 s t a t i o n s h a v e b e e n fo u n d . D ep th o f o c c u r r e n c e r a n g e s from 990 t o 4640 m e t e r s . W a ll c o m p o s it i o n : The w a l l c o m p o s itio n o f t h i s s p e c i e s i s b e in g s t u d i e d by R. L. K o lp ack an d th e a u t h o r . O nly p r e l i m i n a r y r e s u l t s b a s e d on th e e x a m in a tio n o f f r a g m e n ts o f t h e w a l l o f on e sp e cim en a r e r e p o r t e d h e r e . The f r a g m e n ts w ere m ounted i n L a k e s id e m o u n tin g medium on a g l a s s s l i d e an d ex am in e d w ith a p e t r o g r a p h l c m ic r o s c o p e . U n d e r c r o s s e d n l c o l s , e x t i n c t i o n was c o m p le te a n d re m a in e d so when t h e m ic ro s c o p e s t a g e was r o t a t e d i n d i c a t i n g t h a t t h e 255 w a l l m a t e r i a l i s i s o t r o p i c . The r e f r a c t i v e in d e x o f th e w a l l m a t e r i a l i s l e s s th a n t h a t o f L a k e s id e ( R . I . = 1 ,5 4 0 ) . T hese a r e t h e p r o p e r t i e s o f o p a l i n e s i l i c a ( K e r r , 1 9 5 9 ). T h ree k i n d s o f e v id e n c e i n d i c a t e t h a t th e w a l l was n o t o r i g i n a l l y c a l c i t e t h a t was s u b s e q u e n tly r e p l a c e d by s i l i c a . F i r s t , no sp e c im e n s o f c a l c a r e o u s s p e c i e s o c c u r r i n g w ith "M l l i o l i n e l l a ” s p . a r e r e p l a c e d b y s i l i c a . S eco n d , c a l c a r e o u s , o r p a r t i a l l y c a l c a r e o u s sp e c im e n s o f t h i s s p e c i e s from s t a t i o n USC 712 c o n t a i n s m a t e r i a l i n th e l a s t and p e n u l t i m ate ch am b ers w h ich i s s t a i n e d by r o s e b e n g a l , p re su m a b ly i n d i c a t i n g t h a t th e sp e cim en .was a l i v e when c o l l e c t e d . F u r t h e r d i s c u s s i o n o f t h i s s p e c i e s i s d e f e r r e d p e n d in g c o m p le tio n o f s t u d i e s on t h e c o m p o s itio n o f t h e w a l l . F a m ily ALABAMINIDAE H o fk e r, 1951 G enus G y r o id ln a d ’O rb ig n y , 1826 G y r o id in a s u b p l a n u l a t a E c h o ls , n . s p . P l a t e XV, F ig u r e 5 D i a g n o s i s : T e s t f r e e , v e r y s m a ll , t r o c h o s p i r a l , b i c o n v e x , and c o m p re sse d ; p e r i m e t e r v e r y s l i g h t l y l o b u l a t e ; edge ro u n d e d ; u m b i l i c u s s h a llo w ; two to two an d a h a l f w h o rls v i s i b l e on t h e d o r s a l s i d e ; o n ly th e s i x t o seven c h am b ers o f t h e l a s t w h o rl v i s i b l e on th e v e n t r a l s i d e ; d o r s a l s u t u r e s g e n t l y c u rv e d a n d f l u s h e x c e p t f o r th e d i s t a l p a r t o f th e s p i r a l B u tu re w h ich i s s l i g h t l y d e p r e s s e d ; v e n - 2 5 6 t r a l s u t u r e s s t r a i g h t , r a d i a l , and s l i g h t l y d e p r e s s e d ; a p e r t u r e a low r e s t r i c t e d i n t e r i o m a r g i n a l a r c h w ith a l i p m idway b e tw e e n t h e p e r i m e t e r and t h e u m b i l i c u s ; s m a ll su p p l e m e n t a r y u m b i l i c a l a p e r t u r e i n t h e l a s t ch am b er; w a l l c a l c a r e o u s , h y a l i n e , f i n e l y p e r f o r a t e , t r a n s p a r e n t o r t r a n s l u c e n t . H o l o t y p e : USNM No. 68721 3; d i a m e t e r 0 .2 0 mm, t h i c k n e s s 0 .1 0 mm; fro m USC 6 8 0 . The h o l o ty p e waB t h e l a r g e s t s p e c i men f o u n d . V a r i a t i o n : T y p i c a l l y , t h e m a rg in i s e v e n ly ro u n d e d i n e d g e v ie w , b u t i n some sp e c im e n s , t h e v e n t r a l s i d e i s more h i g h l y c o n v ex th a n t h e d o r s a l s i d e r e s u l t i n g i n s l i g h t l y rh o m b o id c h a m b e rs . O c c u r r e n c e : T h is s p e c i e s , o c c u r s a t 24 s t a t i o n s i n t h e S c o t i a a n d n o r t h e r n W e d d e ll S e a s fro m 490 t o 3770 m e t e r . . C o m p a ris o n : The s m a ll s i z e , s h a l l o w - u m b i l i c u s , and c o m p re s s e d b ic o n v e x t e s t o f G y r o ld in a s u b p l a n u l a t a d i s t i n g u i s h e s i t from o t h e r m odern s p e c i e s o f t h e g e n u s . The m id d le E o cen e s p e c i e s , Q y r o ld ln a l o t t e n s l s G a r r e t t , i s s i m i l a r , b u t h a s m ore c h am b ers p e r w h o rl ( 8 - 9 ) and i s l e s s com p r e s s e d . FAUNA L R E F E R E N C E LIST 257 FAUNAL REFERENCE LIST F o r a m in if e r a A dercotrym a glom eratum (B rady) = L i t u o l a g lo m e ra ta B rady, 1878, Ann. Mag. N a t. H i s t . , s e r . 5 , v . 1, p . 433, p i . 20, f i g s . 1 a - c . A m m obaculites a g g lu t i n a n s ( d ’O rbigny) = S p i r o l i n a a g g l u t i - n an s d 'O rb ig n y , 1846, Foram . F o s s . V ie n n e, p . 137, p i . 7 > f i g s . 10- 1 2 . A m m obaculites f i l i f o r m i s E a rla n d = A. a g g lu t i n a n s v a r . f l l l f o r m l s E a r la n d . 1934, D isc o v e ry R e p t s . , v . 10, p . 92, p i . 3 , f i g s . 1 1- 1 3 . A m m obaculites f o l i a c e o u s (B rady) = H aplophragm ium fo lia c e u m B ra d y , 1881, Q u a rt. J o u r n . M icr. S c i . , v . 21, p . 5 0 . A m m obaculites f o l i a c e o u s (B rady) form a r e c u r v a E a rla n d = L* f o l i a c e o u s v a r . r e c u r v a E a r la n d , 1934, D isc o v e ry R e p t s . , v . 10, p . 9 3 , p i . 3 , f i g s . 1 4 -1 7 .— ........ AmmobaculOides c y l i n d r o l d e s (E a rla n d ) = S p l r o p l e c t e l l a c y l l n d r o i d e s E a r la n d , 1934, D isc o v e ry R e p t s ., v . X, p . 114, p i . 4 , f i g s . 3 6- 3 8 . Ammodiscus c a t i n u s H oglund. 1947, U ppsula U n iv ., Z o o l. B id r a g , v . 2b, p . 122, p i . 8 , fig B . 1, 7 , p i . 28, f i g s . 1 9 -2 3 ; t e x t - f i g s . 8 2 -8 4 , 105-109. • A m m o flin tin a a r g e n te a E c h o ls , n . s p . A m m o flin tin a t r l h e d r a E a r la n d . 1934, D isc o v e ry R e p t s . , v . 10, p." 9 8 , p i . 3t f i g s . 20- 2 3 . Ammolagena c l a v a t a (Jo n e s and P a r k e r) = Trochammina i r r e g u l a r i s c l a v a t a Jo n e s and P a r k e r , i 8 6 0, Q u a rt. J o u r . G eol. S o c. London, v . 16, p . 304. Am m omarglnulina e n s l s W ie sn e r, 1931, D eu tsch e S fldpo lar E xped. 1901-1903, v . 20 (Z oo lo g y , v . 1 2 ), p . 97, p i . 1 2, f i g . 147. 258 259 A m m oscalaria ten u im arg o (B rady) = H aplophragm ium ten u im arg o B rad y , 1882, Roy. Soc. E d in b u rg h , P r o c ., v . 11 (1880- 1 8 8 2) , no. I l l , p . 7 1 5 . A n g u lo g e rin a e a r l a n d ! P a r r , 1950, B .A .N .Z . A n t a r c t i c R es. Exped. 1929- 1931, s e r . B, v . 5* P t . 6 , p . 341, p i . 12, f i g . 2 1 . A n g u lo g e rin a e a r l a n d i form a p a u p e r a ta (H e ro n -A lie n and E a r l a n d ) = U v ig e rin a a n g u lo s a v a r . p a u p e r a ta H ero n -A lie n and E a r la n d , 1932, D isc o v e ry R e p t ,, v . 4 , p . 3 9 8, p i . 12, f i g s . 4 0 -4 3 . A stram m ina r a r a Rhum bler in.: W ie sn e r, 1931* D eu tsch e Sfld- p o l a r Exped. 1901-1903, v . 20 ( Z o o l., v . 1 2 ), p . 7 8* p i . 2 , f i g . 19 a - b . A s tro n o n io n a n ta r c tic u m P a r r , 1950, B .A .N .Z . A n t r a c t i c R es. E xped. 1929- 1931, s e r . B, v . 5* p t . 6 , p . 371, p i . 15* f i g s . 1 3, 14 a , b . A s tro n o n io n e c h o l s i K e n n e tt, 1967 ( i n p r e s s ) , C o n tr ib . Cushman Found. Foram . R e s e a rc h , v . 18, p t . 3 . A s tr o r h i z a t r i a n g u l a r i s E r l a n d , 1933* D isc o v e ry R e p t s ., v . 7* P . 52, p i . 1, f i g s . 8 , 9 . B a th y s ip h o n d l s c r e t a (B rady) = Rhabdammina d l s o r e t a B rady, 18b1, Q u a rt. J o u r . M icr. S c i . , v . 21, p . 48. ' B a th y slp h o n g r a n u lo s a (B rady) = M a r s ip e lla g r a n u lo s a B rady, 1879, Q u a rt. J o u r . M icr. S c i . , v . 19, p . 3b , p i . 3 , f i g s . 8 , 9 . B a th y s lp h o n r u s tlc u m de F o l i n , 1886, Soc. L in n . B ordeaux, A c te s , v . 40 ( s 6r 4 , tome 1 0 ), p . 284, p i . 8 , f i g . 9 a - c . B a th y slp h o n sp . A. T e s t a s m a ll tu b e o f u n ifo rm d ia m e te r , open a t b o th e n d s , w ith a n n u la r c o n s t r i c t i o n s ; w a ll c o a r s e l y a r e n a c e o u s , b u t e v e n ly f i n i s h e d ; d ia m e te r o f tu b e a b o u t 0 .0 8 mm. B ig e n e r in a m ln u tis s lm a E a r la n d , 1933* D isc o v e ry R e p ts ., v . 7* p . 9b , p i . 3* f i g s . 3 0- 3 8 . B o liv ln a d e c u s s a ta B rad y , 1881, Q u a rt. J o u r . M icr. S c i . , vTST,' p . 28V 1 ’ B o liv ln a p s e u d o p u n c ta ta Hflglund, 1947* U p p sala U n iv ., Z o o l. B id r a g , Bd. 2 6, p . 273* P l» 24, f i g . 5 a - b . 2 6 0 B u c o e lla te n e r r lm a (Bandy) = R o t a l i a te n e r r lm a Bandy, 1950, J . P a le o n to lo g y , v . 24, p . 27b, p i . 42, f i g . 3. B u lim ln a a c u l e a t a d 'O rb ig n y , 1826, Ann. S c i. N a t ., v . 7 . p . 269. B u lim ln a r o s t r a t a B rady, 1884 > R e p t. Voy. CHALLENGER, v . 9 (Z o o lo g y ), p . 408, p i . 5 1 , f i g s . 1 4-15. B u lim in e lla te n u a ta Cushman = B. s u b f u s if o r m is v a r . te n u a ta Cushman, 1927. B u l l. S c r ip p s I n s t i t . O ceanography, Tech. S e r v ., v . 1, p . 149, p i . 2 , f i g . 9 . C a s s id u lln a l a e v i g a t a d 'O rb ig n y , 1826, Ann. S c i . N a t., P a r i s , s e r . 1, v . 7» p . 282, p i . 15, f i g s . 4 -5 . C a s s id u lln a le n s E a r la n d , 193^* D isc o v e ry R e p t s . , v . 10, p . 135, p l T T , f i g s . 17- 2 0 . C a s s id u lln a su b g lo b o sa B rady. 1881, Q u a rt. J o u r . M icr. S c i . , n . s . , v . 2 1, p . 6 0 . C a s s id u lln o id e s c r a s s a (E a rla n d ) = E h re n b e rg ln a c r a s s a E a r la n d , 1929, Roy. M icr. Soc. J o u r . , s e r . 3 , v . 49, p t . 4, p . 329, P i . 3> f i g s . 18- 2 6 . C a s s id u lln o id e s p a r k e r la n u s (B rady) = C a s s id u lln a p a r k e r ia n a B rad y , 1881, Q u a rt. J o u r . M icr. S c i . , n . s . , v . 21, p . 5 9 . C a s s id u lln o id e s p o r r e c t u s H e ro n -A lie n and E a rla n d = C a s s id u - l i n a c r a s s a d 'O rb ig n y v a r . p o r r e c t a H e ro n -A lie n and E a r la n d , 1932, D isc o v e ry R e p ts ., v . 4 , p . 3 5 8, p i . 9 , f i g s . 3 ^ -3 7 . C e r o b e r tln a a r c t l c a (G reen) = C e ra to b u lim in a a r c t i c a G reen, I 9 6 0, M ic ro p a le o n to lo g y , v . 6 , p . 7 1 , p i . 1 , f i g . 1 a - c . C ib lc id e s b r a d l i (T olm achoff) = P la n u lln a b r a d i l T olm ach off, 1934* Ann. C a rn eg ie M us., P i t t s b u r g h , v . 23, p . 3 3 3 . C ib lc id e s g r o s s e p u n c ta tu s E a r la n d , 1934, D isc o v e ry R e p t s ., v . • 10, p . 184, p i . 8 , f i g s . 3 9 -4 1 . C ib lc id e s lo b a t u l u s (W alker and Ja c o b s ) = N a u tilu s l o b a t u l u s W alker and J a c o b s , 1798* i H s Adams E s s a y s , K anm acker's e d . , p . 642, p i . 14, f i g . 3 6 . C ib lc id e s l o b a t u l u s , i r r e g u l a r form . Conotrochamm ina a l t e r n a n s E a rla n d , 1934, D isc o v e ry R e p ts ., v . 10, p . 103, p i . 3, f i g s . 24-27. 261 C onotrocham m ina b u l l a t a (H o g lu n d ), 19^7, U p p sa la U n iv ., Z o o l. B id r a g , v . 26, p . 213, P i* 17, fig * 5* • • C onotrocham m ina k e n n e t t i E c h o ls , n . s p . C onotrocham m ina ru g o s a ( P a r r ) = Trochamm ina r u g o s a P a r r , 1950, B .A .N .Z . A n t a r c t i c R e s e a rc h E xped. 1 929-1931, R e p t s . , s e r . B, v . 5 , p t . 6 , p . 277, p i* 5 , f i g * 5* C onotrocham m ina s p . A. C onotrocham m ina s p . B . C onotrocham m ina s p . C. T e st a low t r o c h o i d s p i r e o f a b o u t two w h o rls w ith f i v e o r s ix cham bers p e r w h o rl, p e r i p h e r y ro u n d e d ; a p e r t u r e a r e a l , o v a t e , b o r d e r e d by a t h i n l i p . T hese r a r e form s c o u ld b e a b e r r a n t i n d i v i d u a l s o f C ontrocham m ina . b u l l a t a . C rib ro s to m o id e s a r e n a c e a (H e ro n -A lie n and E a r la n d ) = T ru n c a - t u l l n a l o b a t u l a (W aler and Ja c o b ) v a r . a r e n a c e a H e ro n - A lie n a n d E a r l a n d , 1922, B r i t i s h A n t a r c t i c ( ''T e r r a Nova") Exped. Z o o l ., v . 6 , n o . 2, p . 208, p i . 7* f i g s . 32-35* C rib ro s to m o id e s c o n t o r t u s ( E a r la n d ) = R e c u rv o id e s c o n t o r t u s E a r l a n d , 1934, D is c o v e ry R e p t s . , v . 10, p . 91* pi* 1 0 , f i g s . 7-19* C r ib r o s to m o id e s J e f f r e y s i (W illia m s o n ) = N o n lo n in a j e f f r e y - s l i W illia m s o n . 1858. R ec. Foram . G r e a t B r i t a i n , Roy. S o c ,, p . 34, p i . 3 , f i g s . 72-73* C rib ro s to m o id e s s c i t u l u s (B rad y ) = H aplophragm ium s c itu lu m ' B rady, l 8 8 l , Q u a rt. J o u r n . M ic r. S c i . , v . 21, p . 50. C rib ro s to m o id e s s p h a e r i l o c u l u s (Cushman) = H a p lo p h rag m o id es s p h a e r ilo c u lu m Cushman, 1910, U .S . N a t l . Museum B u l l . no. 7 1 * p . 1 0 7, t e x t - f i g . 1 6 5 . C r ib r o sto m o id e s s u b g lo b o s u s (Cushman) = H aplophragm o i d e s subgloboBUB Cushman, 1910, U .S . N a t l . Mus. B u l l . no. 71, p . 105, 10b, t e x t - f l g s . 1 6 2 -1 6 4 . C rib ro s to m o id e s u m b i l i c a t u l u s (P e a rc e y ) = H a p lo p h ra g m o ld e s u m b llic a tu lu m P e a rc e y , 1914, Roy. S o c. E d in b u rg h , T r a n s ., v . 49, p t . 4 , n o . 19, p . 1008, p i . 2, f i g s . 8 - 1 0 . C rib ro s to m o id e s u m b i l i c a t u l u s s o l d a n i i (E a rla n d ) = Trocham m ina s o l d a n l l E a r la n d , 1936, D is c o v e ry R e p t s , , v . 13, p . 38, p i . 1 , f i g s . 3 2 -3 4 . 262 C rib ro s to m o id e s w ie s n e r i ( P a r r ) = L a b r o s p ir a w ie s n e r i P a r r , 1950, B .A .N .Z . A n t a r c t ic R e s. E xped. 1929-1931* s e r * B* v . 5, p t . 6 , p . 27 2, p i . 4 , f i g s . 2 5 , 2 6 . Cyclammina c a n c e l l a t a B rady, 1879, Q u a rt. J o u r . M icr. S c i . , n . s . , ' v." i'9 , p . 6 2 . Cyclammina o r b i c u l a r i s B rad y , 1884, Rep. Voy. CHALLENGER, v . 9 (Z o o lo g y ), p . 353* P i . 37* f i g s . 1 7 -1 9 . Cyclammina p u s l l l a B rad y , 1884, Rep. Voy. CHALLENGER, v . 9 (Z o o lo g y ;, p . 353* p i . 37* f i g s . 2 0 -2 3 . Cyclammina t r u l l i s s a t a (B rady) = Trochammina t r u l l l s s a t a B rad y , 1 8 7 9, Q u a rt. J o u r n . M icr. S c i . , n . s . , v . 1 9, p . 5 6 , p i . 5 , f i g . 10a , b , 1 1 . C y c lo g y ra ln v o lv e n s (R euss) = O p e rc u lin a in v o lv e n s R e u ss, 1850, D e n k sc h r. Akad. W iss. W ien, v . 1, p . 370, p i . 4 6 , f i g . 30. Cystammina a r g e n t e a E a r la n d , 1934, D isc o v e ry R e p t s ., v . 10, p . 105, p i . 4 , f i g s . 1 7 -1 9 . Cystammina p a u c i l o c u l a t a (B rady) = Trochammina p a u c i l o c u l a t a B rady , 1879* Q u a rt. J o u r . M icr. S c i . , n . s . , v . 19, p . 5b, p i . 5* f i g s . 1 3 -1 4 . D endrophrya e r e c t a W rig h t. 1 8 6 1, Ann. Mag. N a t. H i s t . , s e r . 3, v . 8 , p . 1 2 2, p i . 4 , f i g . 4 - 5 . D e n ta lin a communis d 'O rb ig n y form a l a r v a E a r la n d . 1934, D isc o v e ry R e p t ., v . 10, p . 1 67, p i . .7* f i g s . 4o-4l. D e n ta lin a c u v i e r l( d 'O r b ig n y ) = N o d o sa ria ( D e n t a l ln e ) c u v i e r l d 'O r b ig n y , 1826, Ann. S c i. N a t ., s § r . 1 , tome 7, P . 255. D e n ta lin a f r o b i s h e r e n s l s L e o b lic h and Tappen, 1953, S m ith so n ia n I n s t . , M isc. C o l l . , v . 121, no. 7 , p . 5 5 , p i . 10, f i g s . 1 -9 . D e rita lln a i t t a l L e o b lic h and T appen, 1953* S m ith so n ia n I n s t . , M isc. C o l l . , v . 121, no. 7* P . 56, p i . 10, f i g s . 1 0-12. D is o o r b is t r a n s l u o e n s E a r la n d , 1934, D isc o v e ry R e p t s ,, v . 1 0, p . 181, p i . 8 , f i g s . 20- 2 2 . 263 D orothia sp . A. T e s t m in u te , t r i a n g u l a r i n o u t l i n e w ith s t r a i g h t s i d e s , a b o u t a s w ide a s b r o a d , o n ly s l i g h t l y co m p ressed , p e r i p h e ry t r u n c a t e d , i n i t i a l p a r t a m inute t r o c h o i d w h o rl o f a b o u t f o u r ch am b ers, l a t e r p a r t b i s e r i a l ; cham bers i n c r e a s i n g r a p i d l y i n s i z e a s ad d ed , w id e r th a n h ig h ; s u t u r e s s l i g h t l y d e p re s s e d , a lm o s t s t r a i g h t , a l i t t l e i n - ' . c l i n e d , h i g h e s t a t t h e m id lin e ; a p e r t u r a l f a c e f l a t ; a p e r t u r e an i n t e r i o m a r g i n a l s l i t ; w a ll f i n e l y a re n a c e o u s w ith c a lc a r e o u s cem ent, s u r f a c e somewhat ro u g h . E g g erella n ite n s (W iesner) = V ern eu ilin a bradyi Cushman v a r . n i t e n s W ie sn e r, 1931* D eu tsch e S fldpolar E xped. 1901- 19031 v r 20, Z o o l ., v . 12, p . 9 9 , p i . 1 3, f i g . 1 5 4 a ,b . E g g e r e ll a p a r k e r a e (U chio) = K a r r e r i e l l a p a r k e r a e U chio, I9 6 0 , Cushman Found. Foram. R e se a rc h , Spec. P u b l. no. 5 , p . 5 6, p i . 2 , f i g s . 2 1- 2 3 . Ehrenberglna glab ra H eron-A lien & Earland = Ehrenbergina hy s t r ix glab ra H eron-A lien & Earland, 1922, B r itis h Ant. ( T e r ra Nova1 ') E xped. 1910, N a t. H i s t . R e p t. Z oology, v . 6 , n o . 2, p . 140, p i . 5 , f i g s . 1- 6 . Ehrenbergina trig o n a Gofis = E. serra ta Reuss v a r. trigon a GoSb, 1396, Mus. Comp. Z ool. B u ll., v . 29, p . 49, p i . 6 , f i g s . 1 8 3-184 . E ilo h e d r a w e d d e lie n s is (E a rla n d ) = E p o n id es w e d d e lle n s is E a r la n d , 1936, D is c o v e ry R e p t . , v . 13* P« 57* p i* 1* f i g s . 6 5 - 6 7 . E p is to m i n e l l a a r c t l c a G reen, i 9 6 0 , M ic ro p a le o n to lo g y , v. 6 , p . 7 1 , p i . 1 , f i g . 4 a - b . E p is to m in e lla e x ig u a (B rady) = P u lv ln u lln a e x lg u a B rady, 1884, Rep. Voy. CHALLENGER, v . 9 (Z o o lo g y ), p . 6 9 6, p i . 1 0 3, f i g s . 13* 14. E p o n id e s tu m id u lu s (B rady) = T r u n c a tu lin a tu m id u la B rady, 1884, Rep. Voy. CHALLENGER, v . 9 (Z o o lo g y ), p . 6 6 6 , p i . 9 5 * f i g . 8 . E p o n id e s s p . A. F i s s u r l n a a n n e c te n s (Burrow s and H o llan d ) = Lagena a n n e c te n s B urrow s and H o lla n d , in. J o n e s , T. R ., 1895* P a la e o n to g r . S o c ., London, p . 203, P i . 7* f i g . l l a - b . F i s s u r l n a f l m b r l a t a (B rady) = Lagena f l m b r i a t a B ra d y , 1881, Q u a rt. J o u r . M lcr. S c i . , n . s . , v . 21, p . b l . 264 F i s s u r l n a m a r g in a ta (M ontagu) = V erm lculum m arg in atu m Montagu* 1803, T e s ta c e a B r i t a n n i c a , p . 5 2 4 . F i s s u r l n a s e m lm a r g in a ta R eu ss = L agena m a r g ln a ta (M ontagu) v a r . s e m lm a rg in a ta R e u s s , 1 8 7 0 , K. Akad. W ls s. W ien, M ath. -N a tu rw . C l . , S i t z b e r . , v . 6 2 , p . 4 6 8 . F i s s u r l n a s p . A. T e s t b r o a d l y f u s i f o r m i n s i d e v ie w , o n ly s l i g h t l y c o m p re sse d , m arg in ro u n d e d ; s u r f a c e sm o o th , w ith o u t k e e l , b u t m a rg in som ewhat t h ic k e n e d , b l u n t e d p o i n t e d b o s s a t a d a p e r t u r a l e n d ; a p e r t u r e f i s s u r i n e , l a r g e , f u n n e l-s h a p e d ; w a ll h y a l i n e , n o t c l e a r , t h i c k . F i s s u r l n a s p . B. T e s t o v a te i n s i d e v ie w , s l i g h t l y p ro d u c e d a t a p e r t u r a l e n d , s l i g h t l y c o m p re sse d , m arg in ro u n d e d ; s u r f a c e sm ooth, w ith o u t o r n a m e n ta tio n o f any k in d ; a p e r t u r e f i s s u r i n e , o v a t e , s m a ll . F l o r i l u s .la p o n ic u s (A sano) = P seu d o n o n io n jap o n ic u m A sano, 1 9 3 6, G e o l. S o c . J a p a n , J o u r . , v . 4 3 , p . 3 4 7, t e x t - f i g . A-C. F u rs e n k o in a e a r l a n d l ( P a r r ) = B o l i v i n a e a r l a n d ! P a r r , 1950, B .A .N .Z . A n t a r c t i c R e s. E xped. 1929-1931* s e r . B, v . 5* p t . 6 , p . 3 3 9, p i . 1 2, f i g . 16a , b . F u r s e n k o in a f u s i f o r m i s (W illia m s o n ) = B u lim in a p u p o id e s v a r . f u s i f o r m l s W illia m s o n , 1 8 5 8, On t h e R e c e n t f o r a m i n l f e r a o f G re a t B r i t a i n , Roy. S o c. London, p . 6 3 , p i . 5 , f i g s . 1 2 9 -1 3 0 . G a u d ry in a f e r r u g i n e a H e ro n -A lie n and E a r l a n d , 1922, B r i t i s h A n t a r c t i c ( " T e r r a N ova") E x p e d ., 1910, Z o o l . , v . 6 , n o . 2 , p . 1 2 3 , p i . 4 , f i g . 1 3 -1 5 . G a u d ry in a m in u ta E a r l a n d , 1934, D is c o v e ry R e p t s . , v . 10, p . 1 2 1, p i . 5* f i g s . 4 5 , 4 6 . G a u d ry in a p a u p e r a t a E a r l a n d , 1934, D is c o v e ry R e p t s . , v . 10, p / i s i / p i . 5 , " f i g s . 47-49. G la n d u lin a a n t a r c t i c a P a r r , 1950, B .A .N .Z . A n t a r c t i c R e s. E xped. 1 9 2 9 -1 9 3 1 , r e p t . s e r . B, v o l . 5 , p t . 6 , p . 3 3 4, p i . 1 2, f i g s . 8 , 9 . G l a b r a t e l l a m ln u tls s lm a ( C h a s te r ) = D i s c o r b i n a m ln u tls s lm a C h a s te r , 1892, S o u th p o r t S o c. N a t, S c i , R e p t . , 1 s t R e p t. ( 1 8 9 0- 9 1 ) , A p p e n d ., p . 6 5 , p i . 1. f i g . 1 5 a -c . 265 G l o b i g e r i n a b u l l o i d e s d 'O r b ig n y , 1 8 2 6, Ann. S c i . N a t . , s e r . 1 , v o l . 7* p . 2 7 7} M odules n o . 17. G lo b ig e rin a pachyderma (E hrenberg) = A ri s t e r o s p l r a p ach y r- derma E hrenberg, l 8 6 l , K. P re u s s . Akad. W iss. B e r lin , M o n a tsb er., p . 2 7 6, 2 7 7 , 3 0 3 * G l o b i g e r i n a q u in q u e lo b a N a tla n d , 1938* C a l i f . U n i v ., S c r l p p s I n s t . O c e a n o g ra p h y , B u l l . , T ech . S e r . , v o l . 4 , no.. 5 , p . 149, p i . 6 , f i g . 7 . G l o b i g e r i n i t a g l u t i n a t a (E g g e r) = G l o b i g e r i n a g l u t i n a t a E g g e r, 1 8 9 3* A b h a n d l. K. B a y e r. A kad. WissT Mflnchen, C L II, v o l . 18, p . 371* P i . 13* f i g s . 1 9 -2 1 . G lo b ig e r in ita u v u la (E hrenberg) = P y lo d ex ia u v u la E hrenberg, I 8 0 I , K. P re u ss. Akad. W ise. B e r lin , M o n tsb er., pp. 2 7 6, 277* 3 0 8 . G l o b o r o t a l i a i n f l a t a ( d 'O r b ig n y ) = G l o b ig e r in a i n f l a t a d 'O rb ig n y , 1839, in Barker-Webb and B erth e l o t , H is t. N at. l i e s C a n a rie s, "F o r a m in if e r e s ," v o l. 2, p t . 2, Z o o l., • P . 13^* P i . 2, f i g s . 7 - 9 . G l o b o r o t a l i a s c i t u l a (B rad y ) = P u l v i n u l i n a s c i t u l a B ra d y , 1 882, Roy. S oc. E d in b u rg h , P r o c . , v o l . 11 ( 1 8 8 0 - 8 2 ) , n o . I l l , p . 7 1 8 . G l o b o r o t a l i a t r u n c a t u l i n o i d e s ( d 'O r b ig n y ) = R o t a l i n a t r u n c a - t u l i n o l d e s d 'O r b ig n y , 1839, i n B arker-W ebb a n d B e r t h e l o t , H i s t . N a t. l i e s C a n a r i e s , F o r a m i n i f e r e s , " v o l . 2 , p t . 2 , p . 1 3 2 , p i . 2 , f i g s . 2 5 -2 7 . G lom osplra c h a ro id e s (Jo n es & P ark er) = Troohammina squama- t a c h a ro id e s Jones & P a rk e r, i8 6 0 , Q uart. Jo u rn . G eol. S o c . , v . l b , p . 3 0 4 . v . G lo m o sp lra g o r d l a l l s ( J o n e s & P a r k e r ) = Trocham m ina squam a- t a g o r d l a l l s J o n e s & P a r k e r , i 8 6 0 , Q u a r t. J o u r n . G e o l. SocT , v . 1 6 , p . 304. G y ro id in a o r b i c u l a r i s d 'O rb ig n y , 1 8 2 6, Ann. S c i. N a t., s e r . 1, v. 7* P . 2 7 8 . G y r o id in a s o l d a n i i d 'O r b ig n y , 1826, Ann. S c i . N a t . , s e r 1, ’ IbmTY, P .' ’ 278V G y r o id in a s u b p l a n u l a t a E c h o l s , n . s p . 266 : H anzaw aia c o m p la n a ta ( S id e b o tto m ) = D ls c o r b in a b e r t h e l o t l v a r . c o m p la n a ta S id e b o tto m , 1918, Roy. M ic r. S o c. London, J o u r . , p . 2 5 3 , p i . 6 , f i g s . 1- 3 . H a p lo p h ra g m o id e s b r a d y l (R o b e rts o n ) = Trocham m ina b r a d y l R o b e r ts o n , 1691* Ann. Mag. N a t. H i s t . , s e r . b , v . 7* p . 3 8 8 . H a p lo p h ra g m o id e s c a n a r l e n s l s d 'O r b ig n y , 1938, in.: B a r k e r - Webb and B e r t h e l o t , H i s t . N a t. l i e s C a n a r ie s , v . 2, p t . 2 , p . 1 2 8 , p i . 2 , f i g s . 3 3 , 3^ . H a p lo p h ra g m o id e s c f . 'H . k i r k i W ickenden, 1932, Roy. S o c. C anad a, P ro c . T r a n s . , s e r . 3 , v . 26, s e c . 4 , p . 8 5 * p i . 1 , f i g . l a - c . H aplophragm o1 d e s p a r k e r a e (U chio) = R e c u r v o i d e l l a p a r k e r a e U c h io , 1980, Cushman Found. Foram . R e s . , Sp. P u b l. n o . 5* P . 53* P i . Is f i g s . 18, 19. H a p lo p h ra g m o id e s q u a d r a tu s E a r l a n d , 1934, D is c o v e ry R e p t s . , v . 1 0 , p . 8 8 , p i . 3 , f i g . 7 - 8 . H em isphaeram m ina b r a d y l L e o b lic h and T appen, 1957* U .S . N a t l . M us., B u l l . , n o . 215, P- 224, p i . 72, f i g . 2 a - b . H e r o n a l l e n i a l i n g u l a t a (B urrow s a n d H o lla n d ) = D ls c o r b in a l i n g u l a t a B urrow s and H o lla n d , i n : J o n e s , 1895* M onogr. fo ra m . C ra g , p t . 2, p i . e x p l . , p i . 7* f i g . 3 3 a - c . H e r o n a l l e n i a p a r v a P a r r , 1950, B .A .N .Z . A n t a r c t i c R e s. E x p e d . 1929- 1 9 3 1, s e r . B, v . 5* p t . 6 , p . 3 5 8, p i . 14, f i g . 1 0 . H e r o n a l l e n i a w i l s o n i (H e ro n -A lie n & E a r la n d ) = D ls c o r b in a w i l s o n l H e ro n -A lie n & E a r la n d , 1922, B r i t i s h A n t. ( " T e r r a Nova") E x p ., 1910, N a t. H i s t . R e p t. Z o o lo g y , v . 6 , n o . 2 , p . 206, p i . 7 , f i g s . 1 7- 1 9 . H lp p o c re p in a p u s l l l a H e ro n -A lie n and E a r l a n d , 1930, Roy. M ic r. S oc. J o u r . , s e r . 3 , v . 5 0 , p . 6 9 , p i„ 3 , f i g s . 3 ^ -3 5 . H ip p o c re p in e 1 1 a c r a s s a H e ro n -A lie n and E a r la n d = H. h i r u d i - n e a v a r . c r a s s a H e ro n -A lie n an d E a r la n d , 1932, Roy. M icr. S o c. J o u r , , s e r . 3 , v . 52, p t . 3 , p . 259, p i . 2 , f i g s . ! - 3 . H orm osina d a v i s l ( P a r r ) = Reophax d a v l s i P a r r , 1950, B .A .N .Z . A n t a r c t i c R e s e a rc h E x p ed . 1929-1931* R e p t s . , s e r . B, v . 5 , p t . 6 , p . 2 6 5, p i . 4 , f i g . 11. 267* Hormosina g lo b u lif e r a Brady. 1879* Q uart. J o u r. M icr. S c i ., n.B., vT 19* P . 6 0, p i . 4, f i g s . 4 -5 . H orm osina l a p l d i g e r a R hum bler, 1905* D e u ts c h . Z o o l. G e s ., V e r h ., p . 1 0 3 -1 0 4 , t e x t - f i g . 8 . Hyperammina c y l i n d r i c a F a r r , 1950, B .A .N .Z . A n t a r c t i c R e s. E x p ed . 1 9 2 9 -1 9 3 1 , s e r . B, v . 5* P t . 6 , p . 254, p i . 3 , f i g . 5 . Hypercammina la e v ig a ta J . W right = Hyperammina e lo n g a ta v a r. la e v ig a ta J . W right, 1891* Roy. I r i s h Acad. P ro c ., s e r. 3 , v. 1 ( 1 8 8 9- 9 1 )* no. 4, p . 466, p i . 2 0, f i g . 1 . Hyperammina l a e v i g a t a J . W rig h t v a r . A. T e s t c o n s i s t i n g o f a f u s if o r m o r t e a r - d r o p sh ap ed p r o - l o c u l u s f o llo w e d by an e lo n g a te t u b u l a r se co n d cham ber i n i t i a l l y o f s m a l l e r d ia m e te r th a n th e p r o l o c u l u s ; t u b u l a r cham ber s t r a i g h t , t a p e r i n g . s l i g h t l y to w a rd th e p r o l o c u l u s , w ith d i s t i n c t a n n u la r c o n s t r i c t i o n s ; a p e r t u r e th e open end o f th e tu b e ; w a l l c o a r s e l y a re n a c e o u s , b u t sm o o th ly f i n i s h e d . The s t r a i g h t t e s t an d c o a r s e l y a re n a c e o u s w a l l d i s t i n g u i s h e s t h i s v a r i e t y from H. l a e v i g a t a . Hyperammina su b n o d o sa B ra d y , 1884, R e p t. Voy. CHALLENGER, v . 9 (Z o o lo g y ), p . 159* P i . 2 3 , f i g s . 1 1 -1 4 . Hyperam m ina t e n u i s s im a H e ro n -A lie n an d E a r la n d = H. e l o n g a t a B rady v a r . t e n u i s s im a H e ro n -A lie n and E a r la n d , 1922, B r i t . A n t a r c t i c ( " T e r r a Nova") E x p e d ., 1910, N a t. H i s t . R e p t . , Z o o l ., v . 6 , n o . 2, p . 8 8 , p i . 1, f i g . 17. Hyperammina s p . A. I s l a n d i e l l a i s l a n d i c a (Nflrvang) = C a s s l d u l in a i s l a n d l c a N drvang, 1945* The z o o lo g y o f I c e l a n d , v . 2 , p t . 2, p . 4 l , t e x t - f i g B . 7* 8 d - f . I s l a n d i e l l a q u a d r a ta (Cushman an d H ughes) = C a s s l d u l i n a s u b g lo b o s a B rad y v a r . q u a d r a ta Cushman and H ughes, 1 9 2 5, C o n tr . Cushman L ab. Foram . R e s ., v . 1, p t . 1, p . 15* p i . 2 , f i g . 7 a - c . J a c u l e l l a c f . J . o b tu s a B ra d y , 1882, Roy. S oc. E d in b u rg h , P ro c .* v . 11 (1 8 8 0 -1 8 8 2 ), p . 714. K a r r e r l e l l a a p l c u l a r l s (Cushman) = G a u d ry in a a p l c u l a r i s Cushman, 1911, U .S . N a t l . Museum, B u l l . 71* p t . 2, p . 6 9 , t e x t - f i g . 110 a , b . 268 K a r r e r l e l l a b r a d y l (Cushman) = G a u d ry in a b r a d y l Cushman, 1911, U .S . N a t l . Museum, B u l l . 71, p . 6 7 , t e x t - f i g . 107a - c . K a r r e r l e l l a c a t e n a t a (Cushman) = T e x t u l a r i a c a t e n a t a C ush man, 1911j U .S . N a t l . Museum B u l l . n o . 7 1 , p . 2 3, t e x t - f i g s . 3 9j 4 0 . K a r r e r l e l l a d e fo rm ls ( E a r la n d ) = G a u d ry in a d e fo rm is E a r la n d , 193^, D is c o v e ry R e p t s . , v . 10, p . 120, p i . 5 , f i g . 3 7 -4 0 . K a r r e r l e l l a n o v a n g lia e (Cushman) = G a u d ry in a b a c c a t a Schw ager v a r . n o v a n g lia e Cushman, 1922, U .S . N a t l. Museum, B u l l . n o. 104, p . 7 6 , p i . 1 3 , f i g . 4 . K eram o sp haera m u rra y i B ra d y , 1882, Ann. Mag. N a t. H i s t . , s e r . 5 , v . 10, p . 243, P i . 13, f i g . 1 - 4 . L agena c f . L. a s p e r a R e u ss, 1862, K. A kad. W is s. W ien, M a th .-N a tu rw . C l . , S l t z b e r . , v . 4 4 , p t . 1, p . 3 0 5 , p i . 1, f i g . 5 . L agena d ls to m a P a r k e r and J o n e s in.: B ra d y , 1864, L in n . S oc. London, T r a n s . , v . 2 4, p t . 3 , p . 4 6 7 , p i . 4 8 , f i g . 6 . L agena e lo n g a t a (E h re n b e rg ) .= M i l l o l a e lo n g a ta E h re n b e rg , 1844, K. P r e u s s . A kad. W iss. B e r l i n , p . 274. L agena m e r i d i o n a l l s W ie sn e r = L. g r a c i l i s W illia m so n v a r . m e r i d l o n a l i s W ie sn e r, 1931, D e u tsch e S tid p o lar E x p e d ., V. 20 (Z o o l. v . 1 2 ), p . 117, p i . 18, f i g . 211, Lagena n e b u lo s a Cushman = L. l a e v i s (M ontagu) v a r . n e b u lo s a Cushman, 1923, U .S . N a t l. Museum B u l l . no. 104, p. 29, p i . 5, f i g s . 4-5. L agena q u a d r a l a t a B ra d y , 1881, Q u a rt. J o u r . M ic r. S c i . , n . s . , v . 2 1 , p . 6 2 . L in g u lin a t r a n s l u c i d a H e ro n -A lie n and E a r la n d , 1932, D is c o v e ry R e p t . , v . 4 , p . 3 8 7, p i . 12, f i g s . 9 - 1 1 . M a r s l p e l l a c y l i n d r i c a B ra d y , 1882, P r o c . Roy. S o c. E d in b u rg h , v . 1 1 , p . *714. M a r t l n o t t l e l l a a n t a r c t l c a ( P a r r ) = S o h e n c k le ll a a n t a r c t l c a P a r r , 1950, B .A .N .Z . A n t a r c t i c R es. E x p e d ., s e r . B, v . 5 , Pt. 6 , p . 284, p i . 5 , f i g . 27. 269 M a r tin o ttie 1 1 a m i l l e t t i (Cushman) = L l s t e r e l l a m i l l e t t l Cushman, 1936 * Cushman Lab. Foram. R e s e a rc h , S pec. P u b l. n o . 6 , p . 41, p i . 6 , f i g , 10. M e lo n ls c f . M. a f f i n i s (R euss) = N o n lo n ln a a f f l n l s R e u ss, 1851, D eu tsch e g e o l . G e s e ll . Z e i t s c h r . , v . 7 , p . 339. M elo n ls pom.pll i o i d e s ( P i c h t e l and M oll) = N a u tilu s pom pi- l i o l d e s F i c h t e l and M oll, 1798, T e s ta c e a m ic ro s c o p ic a , p . 3 1, p i . 2 , f i g s . a - c . M e lo n ls u m b l l i c a t u l u s (H e ro n -A lie n and E a r la n d ) = A nom allna u m b i l i o a t u l a H e ro n -A lie n and E a r la n d . 1932, D isc o v e ry R e p t s . , v . 4 , p . 42 6, p i . 14, f i g s . 4 0 -4 2 . M iliainm ina a re n a c e a (Chapman) = M i l i a l i n a o b lo n g a v a r . a re n a c e a Chapman, 1916, B r i t . A n t a r c t ic E xped. 1907- 1909, R e p ts . S c i. I n v e s t . , G eo l. v . 2, p t . 3, p . 59* p i . 1, f i g . 7 . M iliam m lna l a t a H e ro n -A lie n and E a r la n d , 1930, Roy. M icr. S o c ., J o u r . s e r v . 3, v . 50, p . 43, p i . 1, f i g s . 1 3 -1 7 . M i l i o l i n e l l a su b ro tu n d a (M ontagu) = V erm iculum Bubrotundum M ontagu, 1803, T e s ta c e a B r l t a n n i c a p . 521. " M i l i o l i n e l l a " sp . N odellum m embranacea (B rady) = Reophax m em branacea B rady, 1879* Q u a rt. J o u r . M ic r. S c i . , n . s . , v . 19, p . 53, p i . 4 , f i g . ' 9 . N o d o sa ria d o l i o l a v i s P a r r , 1950, B .A .N .Z . A n t a r c t i c Re s e a r c h E xped. 1929-1931* s e r . B, v . 5* p t . 6 , p . 330, p i . 1 2 , f i g . 2 . Nodosinum g a u ssic u m (Rhum bler) = N o d o s in e lla g a u s s i c a R hum bler, 1913* P la n k to n E xped. H u m b o ld t-S tif tu n g , E r g e b ., v. 3 , L .S ., p p . 4 5 2, 459* 460, p . 4 5 3 , t . f . 1 6 3; p . 459* t . f . 1 6 9j p . 461, t . f . 1 7 2. N o n io n e lla b r a d i i (’Chapman) = N o n lo n in a soapha v a r . b r a d i i Chapman, 1916, B r i t . A n t a r c t i c Exped. 1907-1909* R e p ts . S c i . I n v e s t . , G e o l., v o l . 2, p t . 3 , p . 71, p i . 5 , f i g . 4 2. N o n io n e lla l r l d e a H e ro n -A lie n an d E a rla n d , 1932, D isc o v e ry R e p t s ., v . 4 , p . 4 3 8 , p i . 1 6, figB. 1 4 -1 6 . 270 N u t t a l i d e s u m b o n ife ra (Cushman) = P u l v l n u l i n e l l a u m b o n ife ra Cushman, 1933* C o n tr. Cushman L ab. Foram . R e s ,, v . 9* p t . 4 , p . 9 0 , p i . 9 , f i g s . 9 a - c . O o lln a a p i o u l a t a R e u ss. 1851, N aturw . A b h ., W ien, Bd. 4 , p . 22, p i . 2 , f i g . 1 . O o lln a melo d 'O rb ig n y , 1 8 3 9, Voyage d an s l ’Am erique M e ri- d io n a le s F o r a m in if e r e s , tome 5 , p t . 5 , p . 20, p i . 5, f i g . 9. O r i d o r s a i l s m arcId a (E m ilia n a ) = E p o n id e s m a rc id a E m ilia n a , 1954, P a la e o n to g r . I t a l i c a , v . 4b (new s e r , , v . 1 8 ), p . 124, p i . 2 2, f i g . 24 a - c . O r i d o r s a i l s s id e b o tto m i (E a rla n d ) = E p o n id e s s ld e b o tto m i E a r la n d , 1934, D isc o v e ry R e p t s ., v . 10, p . 188, p i . 7 , f i g s . 3 3 -3 5 . O r i d o r s a l i s t e n e r a (B rady) = T r u n c a tu l i n a t e n e r a B rad y , 1884, R e p t. Voy. CHALLENGER, v . 9 (Z o o lo g y ), p . 6 6 5 , p i . 95, f i g . 11. O r i d o r s a l i s sp . P a r a f i s s u r i n a c u r t a P a r r , 195.0, B .A .N .Z . A n t a r c t i c R e se a rc h E xped. 1929-1931, s e r . B, v . 5 , p t . 6 , p . 318, p i . 10, f i g s . 6 - 7 . P a r a f i s s u r i n a d o rb lg n y a n a (W iesn er) = E l l l p s o l a g e n a d o rb ig n y a n a W ie sn e r, 1931, D eu tsch e S tld p o lar Exped. 1 9 0 1 -0 3 , v . 20 (Z o o l. v . 1 2 ), p . 127, p i . 24. P a r a f i s s u r i n a f u s u l i n i f o r m i s L o e b lic h an d T appen, 1953, S m ith so n ia n I n s t . , M isc. C o l l . , v . 121, n o . 7 , P . 79, p i . 14, f i g s . I 8 - 1 9 . P a r a f i s s u r i n a l a t e r a l i s (Cushman) = L agena l a t e r a l i s Cush man, 1913, U .S . N a t l . Museum, B u l l . n o . 71, P t . 3, P- 9, p i . 1 , f i g . 1 . P a r a f i s s u r i n a v e n t r i c o s a ( S i l v e s t r i ) = L agena v e n t r l c o s a S l l v e s t r i , 1904, R. A ccad. S c i . T o rin o , v . 39, p .. 11, t e x t - f i g . 6 . P a t e l l i n a a n t a r c t l c a P a r r , 1950, B .A .N .Z . A n t a r c t i c Exped. 1929-1931, s e r . B, v . 5, p t . 6 , p . 3 5 2 , p i . 1 3, f i g s . 19- 2 1 . 271 P e l o s i n a d is to m a M i l l e t t , 1904, Roy. M ic r. S oc. London, J o u r . , p . 6 0 8 , p i . 11, f i g s . 5 - 6 . P e l o s i n a v a r l a b l l l s B ra d y , 1879* Q u a rt. J o u r . M ic r. S c i . , v . 19* P . 30, p i . 3* f i g s . 1 - 3 . P l a c o p s i l l n e l l a a u r a n t i a c a E a r l a n d , 1934, D is c o v e ry R e p t s . , p . 9 5 , p i . 3 , f i g . 1 8 . P o rta tro c h a m m in a a n t a r c t l c a ( P a r r ) = Trocham m lna a n t a r c t l c a P a r r , 1950, B .A .N .Z . A n t a r c t i c R e s. E x p e d ., 1929-1931* s e r . B, v . 5* p t . 6 , p . 280, p i . 5 * f i g s . 2 - 4 . P o rta tro c h a m m in a e l t a n i n a e E c h o ls , n . s p . P o rta tro c h a m m in a w i e s n e r ! ( P a r r ) = Trocham m lna w i e s n e r ! P a r r , 1950, B .A .N .Z . A n t a r c t i c R e s. E xped. 1929-1931* s e r . B, v . 5, p t . 6 , p . 279* p i . 5* f i g . 14. Psam m osphaera f u s c a S c h u lz e , 1875* I I J a h r . Comm. w i s s . U n t. d e u tB c h . M eer i n K i e l , p . 1 1 3 , p i . 2, f i g s . 8 a - f . P s e u d o b o liv in a a n t a r c t l c a W ie sn e r, 1931* D e u tsc h e SiHdpolar E xped. 1 9 0 1 -1 9 0 3 , v . 20 (Z o o l. v . 1 2 ), p . 9 9 , p i . 21, f i g s . 2- 5 7 * 2 5 8 . P se u d o b o 11v i n a s p . A. T e s t m in u te , e l o n g a t e , s l e n d e r , som ewhat c o m p re sse d , t a p e r i n g g r a d u a l l y , p e r i p h e r y ro u n d e d ; cham bers d i s t i n c t , i n c r e a s i n g r e g u l a r l y i n s i z e a s a d d e d , a b o u t 12 i n num b e r ; s u tu re B s l i g h t l y d e p r e s s e d , i n c l i n e d , s l i g h t l y c o n vex to w a rd th e a p e r t u r a l en d ; a p e r t u r e on e l o n g a t e n a r row s l i t e x te n d in g from th e s u t u r e i n t o th e a p e r t u r a l f a c e ; w a l l v e ry f i n e g r a i n e d , a lm o s t t r a n s p a r e n t . P u l l e n i a o s l o e n s i s F e y lin g - H a n s s e n , 1954, N orsk G e o l. T i d s s k r . , v . 33* no. 3 - 4 , p . 194. P u l l e n i a sim p le x R hum bler i n W ie s n e r, 1931* D e u tsc h e Stld p o l a r E x ped. 1 9 0 1 -1 9 0 3 , v . 20 ( Z o o l ., v . 1 2 ), p . 132, p i . 2 2 , f i g . 2 6 3 . P u l l e n i a s u b c a r l n a t a ( d 'O r b ig n y ) = N o n io n in a s u b c a r l n a t a d 'O r b ig n y , 1 8 3 9* Voyage d a n s l'A m e riq u e M d r id io n a le ; • F o r a m in l f e r e s , v . 5* p t . 5* P . 28, p i . 5 , f i g s . 2 3 -2 4 . P u l l e n i a s u b s p h a e r ic a P a r r , 1950, B .A .N .Z . A n t a r c t i c R es, E xped. 1929-1931* s e r . B, v . 5 , p t . 6 , p . 3 4 6, p i . 13, f i g . 6 . 272 P yrgo m u rrh in a (Schw ager) = B i l o c u l i n a m u rrh in a Schw ager, 1866, N ovara E xped. 1857-1859* G e o l. T h e i l . , v . 2, p . 2 0 3, p i . 4 , f i g s . 15 a - c . Q u in q u e lo c u lin a sem lnulum (L in n e ) = S e r p u la sem lnulum L in n d , 1758, Sy&t. N a t . , e d . 10, v . 1, p . 7 8 6 . Reophax ad u n ca B ra d y j 1882, Roy. S o c. E d in b u rg , P r o c ., v . l lT T B B o - 1 882) , n o . I l l , p . 715 . Reophax c u r t u s Cushman, 1920, U .S . N a t l . Museum B u l l . n o . 104, p . 8 , p i . 2 , f i g s . 2- 3 . Reophax d i s t a n s B ra d y , 1884, Q u a rt. J o u r , M ic r. S c i . , v . 2 1 , n . s . , p . 5 0 . Reophax l o n g ! s e a t i f o r m i s Chapman, 1916, B r i t . A n t a r c t i c E xped. 1907-1909* R e p ts . S c i . I n v e s t . , G e o l ., v . 2, p t . 3 , p . 6 3 , p i . 3 , f i g . 1 8 . Reophax n o d u lo s a , 1879* Q u a rt. J o u r . M ic r. S o c ., n . s . , v . 19* P . 52* p i . 4 , f i g s . 7 - 8 . Reophax o v i c u l a (B rady) = H orm osina o v i c u l a B ra d y , 1879* Q u a rt. J o u r . M ic r. S c i . , n . s . , v . 19* p . 6 l , p i . 4 , f i g . 6 . Reophax r e g u l a r i s H oglund, 1947* U p p su la U n iv ., Z o o l. B id r a g , v . 2 6, p . 8 6 , p i . 9 , f i g s . 1 1 -1 2 . Reophax c f . R. r o s t r a t a H oglund , 1947* U p p su la U n iv ., Z o o l. B id r a g , v . 2 6 , p . 8 7 * p i . 9* f i g . 8 . R eophax s u b d e n t a l i n i f o r m ! s P a r r , 1950, B .A .N .Z . A n t a r c t i c R es. E xped. 1 9 2 9 -1 9 3 1 , s e r . B, v . 5* p t . 6 , p . 2 6 9, p i . 4 , f i g . 2 0 . Reophax s u b f u s if o r m i s E a r la n d , 1988, D isc o v e ry R e p t s . , v . 7* P . 7 4 , p i . 2, f i g s . 1 6 -1 9 . Reophax tu r b o Go4b, 1 8 9 6, Mus. Comp. Z o o l . , B u l l . , v . 29, p . 29* p l . 1* f i g s . 2 - 3 . Reophax s p . A. T e s t com posed o f o n e , tw o, o r l e s s commonly, t h r e e ch am b ers; cham bers p y r i f o r m , w id e s t i n th e lo w e r p a r t , t a p e r i n g to w a rd th e v e ry s m a ll a p e r t u r e ; i n m u l t l l o c u l a r form s cham bers l o o s e l y a p p r e s s e d , i n c r e a s i n g r a p i d l y i n s i z e a s ad d ed ; s u t u r e s d e e p ly d e p re s s e d and i n c l i n e d ; w a ll c o a r s e l y a re n a c e o u s ; a p e r t u r e a t t h e end o f a s h o r t n e ck o f d i s t i n c t l y f i n e r t e x t u r e th a n th e r e s t o f th e cham ber. 273 Reophax s p . B. Rhabdammina ? sp . A. Pound o n ly a s b ro k en tu b e s some o f w hich have a d i a m e te r o f 0 .5 mmj f l a r i n g en d s o f some fra g m e n te d tu b e s s u g g e s t a la r g e p r o l o c u l u s ; w a ll c o a r s e l y a re n a c e o u s . R o b e r tln a w le s n e r l P a r r , 1950, B .A .N .Z . A n t a r c t i c Exped. 1929-1931, R e p t s ., s e r . B, v . 5, p i . 6 , p . 3 6 9, p i . 1 5, f i g . 9 . R u d ig a u d ry in a i n e p t a Cushman and M cC ulloch, 1939* A lla n Hancock P a c i f i c E x p e d ., v o l . 6 , n o . 1, p p . 9 4 -9 5 , p i . 9* f i g s . 3- 1 0 . R u p e r tin a s t a b i l l s (W a llic h ) = R u p e r t! a s t a b l l i s W a llic h , 1077, Ann. Mag. N a t. H i s t . , s e r . 4 , f . 19, p . 502, p i . 2 0, f i g s . 1- 1 3 . Saccammlna s p h a e r ic a B ra d y , IIB7 1 , Ann. Mag. N a t. H i s t . , s e r . 4 , v . 7, P* 183* Saccammlna t u b u l a t a R hum bler; in. W ie sn e r, 1931, D eu tsch e S d d p o la r Exped. 1901-1903, v . 20 ( Z o o l., v . 1 2 ), p . 82, p i . 2 3, S te r e o - f i g . a . S a c c o rh iz a ? h e d r ix (Rhum bler) = Tolypammina h e d r ix R hum bler; i n W ie sn e r, 1931, D eu tsch e S u d p o la r Exped. 190 1-1903, v. 20 ( Z o o l., v . 1 2 ), p . 94, p i . 11, f i g . 1 3 0 . S c a b ro o k ia c f . S.. e a r la n d ! W rig h t, 1891, P ro c . Roy. I r i s h A c a d ., s e r . 3, v . 1, n o . 4 , p . 4 77, p i . 20, f i g s . 6 - 7 . S p h a e ro id ln a b u l l o i d e s d 'O rb ig n y , 1826, Ann. S c i . ’N a t ., P a r i s , s b r . 1, v . 7 , p . 2 6 7 . m o d eles, n o . 6 5 . S pirolocam m lna t e n u i s E a r la n d . 1934, D is c o v e ry R e p t s . , v . 10, p . 109, p i . 4 , f i g s . 1 3 -1 6 . S p iro p le c ta m m in a b i f o r m l s ( P a r k e r and J o n e s ) = T e x t u l a r i a a g g lu t i n a n s v a r . b if o r m is P a r k e r and J o n e s , 1865, P h i l o s . T ra n s. Roy. S oc. London* v . 155, p . 370, p i . 15, f i g s . 2 3, 24. S p iro p le c ta m m ln a f i l l f o r m l s E a r la n d , 1934, D isc o v e ry R e p ts ., v . 10, p . 112, p i . 4 , f i g . 3O-3 2 . S p iro p le c ta m m ln a s u b c y l l n d r l c a E a r la n d , 1934, D isc o v e ry R e p t s ., v . 10, p . 112, p i . 4 , f i g s . 3 3 -3 5 . 274 S p iro p lec ta m m ln a t y p ic a L a c r o ix , 1931* Monaco I n s t . Ocean- o g r . , B u l l . no. 5&2, p . 14, t e x t - f i g . 9. S p lro p lec ta m m in a sp . A. S t a l n f o r t h l a co m p lan ata (E gger) = V l r g u l ln a s c h r e i b e r s l a n a v a r . co m p lan ata iEgger. 1895, K. b a y e r . Akad. W is s ., m a th .-p h y s ik . C l . , A bh., v . 18 (1893)* P* 292, p i . 8 , f i g s . 9 1 -9 2 . -Tex tu l a r i a e a r la n d ! P a rk e r 1952, Mus. Comp. Z o o l., B u l l . , v . 106 ( 1951- 5 2) , no. 1 0, p . 458. T e x t u la r i a p a u p e rc u la E a rla n d , 1934, D isc o v e ry R e p ts . 10, p . 114, p i . 5* f i g . 2 7- 2 9 . T e x t u la r i a w ie s n e r! E a r la n d , 1933* D isc o v e ry R e p t s ., v . 7* p . 9 5 * p l . 3 * f i g s . 18- 2 0 . Thurammina e x . g r . T. a l b i c a n s B rady, 1879* Q u a rt. J o u r. M icr. S c i . , n . s . , v . 19* P'. 46. Thurammina p a p i l l a t a B rad y , 1879* Q u a rt. J o u r . M icr. S c i . , n . s . , v . 19* P. 45* p l . 5* f i g s . 4 - 8 . Tolypammina f r l g i d a (Cushman) = G ir v a n e lla f r l g i d a Cushman, 1918, U .S . N a t l. Museum B u l l . no. 1 0 4 ,’ p . 9 3 . T r i l o c u l i n a t r i c a r i n a t a d ’O rbigny, 1826, Ann. S c i. N a t., s ^ r 1, tome 7* p . 2 99, M odeles, no. §4. T r i t a x i s in h a e r e n s (W iesner) = H aplophragm oides c a n a r l e n s l s ( d ’O rbigny) v a r . in h a e r e n s W ie sn e r, 1931* D eu tsch e Stid— p o l a r Exped. 1901-1903, v . 20 ( Z o o l., v . 1 2 ), p . 95* p l . 12, f i g . 137. T r i t a x i s squam ata Jo n e s and P a r k e r , i8 6 0 , G eo l. Soc. London, Q u a rt. J o u r . , v . 16, p . 304. Trochammina a p p re s s a P a r r , 1950, B .A .N .Z. A n t a r c t i c R es. fexped., s e r . B, v . 5, p t . 6, p . 277* p l . 5* f i g . 6 , * 7 a ,b . Trochammina com pacta P a r k e r . 1952, Mus. Comp. Z o o l., B u l l . , v . 10b , no. 10, p . 458, p l . 2 , f i g s . 13-15* Trochammlna c o n ic a E a r la n d , 1934, D isc o v e ry R e p t s ., v . 10, p . 104, p l . 3* f i g s . 4 7 -4 9 . Trochammlna d l s c o r b i s E a r la n d , 1934, D isc o v e ry R e p ts ,, v . 1 0, p . 104, p l . 3 * f i g s . 2 8- 3 1 . 275 Trocham m lna g l a b r a H e ro n -A lie n and E a r l a n d , 1932. D is c o v e ry R e p t s . , v . 4 , p . 3 4 4 , p l . 7* f i g s . 2 6- 2 8 . Trocham m lna g l o b i g e r i n i f o r m i s ( P a r k e r and J o n e s ) = L l t u o l a n a u t i l o l d e a v a r . g l o b i g e r i n i f o r m i s P a r k e r an d J o n e s . l8 b 5 , Roy. S o c . L ondon, P h i l o s . T r a n s . , v . 155, P . 407. Trocham m lna g r l s e a E a r l a n d , 1934, D is c o v e r y R e p t s . , v . 10, p . 1 0 0 , p l . 3 , f i g s . 35- 3 7 . Trocham m lna i n c o n s p i c u a E a r l a n d , 1934, D is c o v e r y R e p t s . , v . 1 0 , p . 1 0 2 , p l . 3 , f i g s . 3 8 -4 0 . Trocham m lna I n t e r m e d i a R hum bler = T. sq u a m ata I n t e r m e d i a R h u m b ler, 193&, K ie l M e r r e s f . , Bd. 2 , H e f t 2 , p , 1 8 b - 187* t e x t - f i g . 27. Trocham m lna l a b l a t a U c h io , i 9 6 0 , Cushman P ound. Foram . Re s e a r c h , S p . P u b l . , n o . 5 , p . 5 9 , p l . 3 , f i g s . 1 5 -1 7 . T rocham m lna m a lo v e n s ls H e ro n -A lie n and E a r l a n d , 1929, Roy. M ic r. S o c. J o u r . , s e r . 3 , v . 4 9 , p t . 4 , p . 3 2 8 , p l . 4 , f i g s . 2 7 -3 2 . Trocham m lna m u l t i l o c u l a t a H o g lu n d , 1947* U p p s u la U n iv ., Z o o l. B i d r a g . , v . 2 b , p . 211, p l . 15, f i g . 5 , t e x t - f i g . 193. Trocham m lna pygm aea H oglund = Trocham m ina g l o b i g e r i n i f o r m i s v a r . pygm aea H o g lu n d , 1947* U p p su la U n iv ., Z o o l. B id r a g , v . 2 6 , p . 2 0 0 , p l . 1 7 , f i g . 3 . Trocham m lna q u a d r i c a m e r a t a E c h o ls n . s p . Trocham m lna q u a d r i l o b a H o g lu n d , 1948, Cushman L ab. Foram . R e s e a r c h , C o n t r i b . , v . 24 , p . 46. Trocham m lna s o r o s a P a r r , 1950, B .A .N .Z . A n t a r c t i c R e s. Ex p e d . , s e r . B, v . 5 , p t . b , p . 2 7 8 , p l . 5 , f i g . 1 5 -1 7 . Trocham m lna s u b c o n lc a P a r r , 1950, B .A .N .Z . A n t a r c t i c R es. E x p e d ., s e r . B, v . 5 , p t . 6 , p . 281, p l . 5 , f i g . 22. Trocham m ina t r l c a m e r a t a E a r l a n d . 1934, D is c o v e ry R e p t s ., v . 1 0 , p . 1 0 3 , p l . 3 , f i g s . 5 0 - 5 2 . Trocham m ina Bp. A. U v ig e r in a a s p e r u l a C z.lzek, 1848, N aturw . A b h ,, v . 2, p l . 1, p . 14b, p l . 1 3 , f i g . 1 4 -1 5 . 276 U v lg e rin a c f . U. a t t e n u a t a Cushman and Renz = U. a u b e r i a n a d 'O rb ig n y v a r . a t t e n u a t a Cushman an d R enz, 1941, C o n tr . Cushman L ab. Foram . R e s . , v . 17, p . 2 1 , p l . 3 , f i g . 17. U v lg e rin a b i f u r c a t a d 'O r b ig n y , 1839* Voyage d a n s l'A m e riq u e M ^ rid io n a le ; F o r a m i n i f e r e s , tome 5* p t . 5* P . 53. V a l v u l l n e r i a l a e v i g a t a P h le g e r and P a r k e r , 1951* Mem. 4 6 , G eo l. S oc. A m erica, p t . 2 , p . 25 , p l . 13, f i g s . 1 1 a ,b , 12a , b . V e r n e u i l in a europeum C h r i s t i a n s e n . 1958, N y tt Mag. Z o o l ., v . 6 , p . 6b . V e r n e u i l in a m in u ta W ie s n e r, 1931* D e u tsc h e S fld p o lar E xped. 1901-1903* v . 20 ( Z o o l ., v . 1 2 ) , p . 99* P l . 13* f i g . 155, p l . 2 3 , f i g . d . V e r n e u i l in a m in u ta W ie s n e r, v a r . A. T e s t m in u te , t r i s e r i a l , somewhat t r i h e d r a l , a b o u t a s wide a s lo n g , a p e r t u r a l and a lm o s t f l a t ; cham b ers b ro a d and low ; a b o u t 12 i n th e a d u l t t e s t ; s u t u r e s d e p r e s s e d , d i s t i n c t on t h e a p e r t u r a l e n d , b u t o b s c u r e i n th e e a r l i e r p a r t o f th e t e s t ; a p e r t u r e a s m a ll i n t e r i o m a r g i n a l a rc h n e a r th e u m b il i c u s ; w a l l c o a r B e ly a r e n a c e o u s f o r th e s i z e o f th e t e s t , c o l o r l i g h t brow n. The s h o r t b ro a d t e s t f l a t t e n e d a t th e a p e r t u r a l end d i s t i n g u i s h e s t h i s v a r i e t y from t y p i c a l V. m in u ta . R a d i o l a r i a n s H e lo th o lu s h i s t r i c o s a J d r g e n s e n , 1905* B e rg e n s Museum S k r i f t e r , p . 137* p l . 16, f i g s . 8 6 - 8 8 . L l t h e l i u s n a u t i l i o l d e s P o p o fsk y , 1 9 0 8 , D e u tsc h e S fld p o la r E x p e d ., v . 10, p . 2 3 0 -2 3 1 , p l . 27, f i g s . 2 - 4 . P e r o m e lis s a d e n t i o u l a t a (E h re n b e rg ) = L l t h o b o t r y s ? d e n t l - c u l a t a E h re n b e rg , K. P r e u s s . Akad. W is s ., B e r l i n , 1844, p . 2 0 3 . P ru n o p y le a n t a r c t l c a D re y e r, 1 8 8 9, J e n a i s c h e Z e i t s c h r . N a tu rw is s . v . 2 3 , N .F . 16, p . 2 4 -2 5 , p l . 5 , f i g . 7 5 . Spongoplegm a a n t a r e t l c u m H a e c k e l, I 8 8 7 , R e p t. S c i e n t i f i c R e s u l t s E x p lo r . Voyage H .M .S. CHALLENGER, Z o o l ., v . 18, p . 9 0 . < 277 S pong opyle o s c u l o s a D re y e r, 1889, J e n a i s c h e Z e i t s c h r . N a t u r w i s s ., v . 2 3, N .F . 16, p . 4 2 -4 3 , p l . 6 , f i g s . 9 9 , 100. S p o n g o tro c h u s g l a c l a l l s P o p o fsk y , 1908, D e u tsc h e S fid p o lar E x p e d ., v . 10, p . 2 2 8 -2 2 9 , p l . 26, f i g . 8 ; p l . 27, f i g . 1; p l . 2 8, f i g . 2 . S p o n g u ru s p y lo m a tic u s R i e d e l, 1958, B .A .N .Z . A n t a r c t i c R e s. E xped. 1 9 2 9-1931, s e r . B, v . 6 , p t . 10, p . 226, p l . 1, f i g s . 1 0, 1 1 . P L A T E S OP P OR A M I N I P E R A (PLATES I THROUGH X V II) 278 PLATE I In t h i s and th e f o llo w in g p l a t e s * t h e maximum dim en s io n s i n m i l l i m e t e r s o f th e sp e c im e n s a r e shown b e s id e th e f i g u r e s . 1 P l a c o p B i l i n e l l a a u r a n t i a c a E a r la n d , X 119; USC 624; H ypotype, USC No. 1121. 2 Hyperammina sp . A, X 27; USC 646; H y p o ty p e, USC No. 1 1 2 2 . 3 Psam m osphaera f u s c a S c h u lz e , X 26; a , s i d e view ; b , a p e r t u r a l v iew ; USC 472; H y p o ty p e, USC No. 1123. 4 AmmodiBcus c a t l n u s H oglund, X 119; a , edge view ; b , s i d e v iew ; USC 5035 H y p o ty p e, USC No. 1124. 5 G lo m o sp lra g o r d l a l l s (J o n e s and P a r k e r ) , X 151; USC 647; H y p o ty p e, USC No. 1125. 6 Saccammlna t u b u l a t a R hum bler, X 6 l : USC 6 4 8 : H vootvoe. USC No. 1125: 7 Tolypammina f r i g i d a (C ushm an), X 119; USC 647; Hypo ty p e , USC No. 1127. 8 Reophax s u b d e n t a l i n i f o r m l s P a r r , X 4 2; USC 6 5 1 ; Hypo ty p e , USC No. 1128. 9 Reophax s p . B, X 54; USC 654 ; H y p o ty p e, USC No. 1129. 10 Reophax s p . A E a r la n d , X 6 0 ; USC 700; H y potype, USC No. 1130. 11 Reophax s p . A E a r la n d , X 6 0 ; USC 700; H yp oty pe, USC No. 1131. 12 Reophax s p . A E a r la n d , X 6 0 ; USC 700; H y p o ty p e, USC No. 1132. 13 Reophax s p . A E a r la n d , X 6 0 ; USC 7 0 0 ; H y p o ty p e, USC No. 1133. 279 PLATE II 1 Reophax o v i c u l a (B ra d y ), X 5 6 ; USC 649: H ypotype, use no, 2 Reophax o v i c u l a (B ra d y ), X 5 6 ; USC 6495 H ypotype, USC No. 1135. 3 Reophax o v i c u l a (B ra d y ), X 565 USC 649: H ypotype, USC No. 1136^ 4 M iliam m ina l a t a H e ro n -A lie n and E a r la n d , X 5 5 5 a , s i d e v iew ; b , a p e r t u r a l view ; ELT 6 5 2 ; H ypotype, USC No. 1137. 5 M iliam m ina a re n a c e a (Chapman), X 74; a , s id e view ; b , a p e r t u r a l view ; USC 6 5 2 ; H ypotype, USC No. I I 3 8 . 6 S pirolocam m ina t e n u i s E a r la n d , X 103; USC 1031; H ypotype, USC No. 1139. 7 A m m o flin tln a a r g e n te a E c h o ls , n . s p . , X 167; a , edge view ; b , s i d e view ; c , o p p o s i t e s i d e ; USC 659; H o lo - ty p e , USNM N o . ' 8 Cystammina p a u c i l o c u l a t a (B ra d y ), X 182; b ro k e n s p e c i men show ing a p e r t u r e s a l t e r n a t i n g on e i t h e r s id e o f t e s t ; a , o r a l view ; b , a b o r a l view ; USC 648; H ypotype, USC No. 1140. 9 Cystammina p a u c i l o c u l a t a (B ra d y ), X 84; USC 648; .Hypotype, USC No. 1141. 10 Cystammina a r g e n t e a E a r la n d , X 200; USC 649; Hypo ty p e , USC No. 1142. 11 H aplophragm oides p a r k e r a e (U c h lo ), X 171; a , s id e view ; b , edge view ; U £>C 6 5 0 ; H ypotype, USC'No. 1143. 281 r 282 PLATE I I I 1 H aplophragm oideB q u a d r a tu s E a r la n d , X 196; a , s id e view ; b , edge v iew ; USC 654; H ypotype, USC No. 1144. 2 H ap lo p h rag m o Id es c a n a r l e n s l s d ’O rb ig n y , X 247; a , s id e v iew ; b , edge v iew ; USC 5 4 9 ; H ypo typ e, USC No. 1145. 3 C rib ro s to m o id e s o o n t o r tu s ( E a r l a n d ) , X 5 6 ; a , edge v iew ; b , s i d e v iew ; USC 503 & 505; H ypo typ e, USC No. 1146. 4 C r ib r o s to m o id e s o o n t o r tu s ( E a r l a n d ) , X 5 6 ; a , edge v iew ; b , s i d e v iew ; USC 503 & 505; H y p o ty p e, USC No. 1147. 5 C r ib r o s to m o id e s s p h a e r i l o c u i u s (C ushm an), X 127; p r o l o c u l u s and f i r s t cham ber o f m e g a lo s p h e ric form ; USC 648; H y p o ty p e, USC No. 1148. 6 C r ib r o s to m o id e s s p h a e r i l o c u i u s (C ushm an), X 127; m ic ro S p h e ric form ; a , edge view ; b , s i d e v iew ; USC 648; H yp oty pe, USC No. 1149. 7 C rib ro s to m o id e s s p h a e r i l o c u i u s (C ushm an), X 127; mega l o s p h e r i c form ; USC 648; H yp oty pe, USC No. 1150. 8 C rib r o s to m o id e s subglobosum (Cushm an), X 5 3 ; USC 475; H yp oty pe, USC No. 1151. 9 C r ib r o s to m o id e s sub glo bosum (Cushm an), X 5 3 ; USC 475; H ypotype, USC No. 1152. 10 Cyclamm ina p u s l l l a B ra d y , X 52; a , edge v iew ; b , s id e view ; USC 520; H ypotype, USC No. 1153. 283 v S S B A i PLATE IV 1 C r ib r o s to m o id e s a r e n a c e a (H e ro n - A lie n and E a r l a n d ) , X 128; a , i n v o l u t e s i d e ; b , e v o l u t e s i d e ; c , edge v ie w ; USC 500;- H y p o ty p e , USC No. 115 4 . * 2 C r ib r o s to m o id e s u m b il i c a tu l u m s o l d a n i i ( E a r l a n d ) , X 1 03; a , ed g e v ie w ; b , e v o l u t e s i d e ; USC 6 8 9 ; Hypo t y p e , USC No. 115 5 . 3 C r ib r o s to m o id e s u m b il i c a tu l u m s o l d a n i i ( E a r l a n d ) , X 2 0 ^ ; ed g e v ie w ; USC 6 8 9 ; U y p o ty p e , USC No. 1156. 4 Trocham m ina q u a d r i c a m e r a t a E c h o ls , n . s p . , X 221; a , v e n t r a l v iew ; b , ed g e v ie w ; c , d o r s a l v iew ; USC 500; H o lo ty p e , USNM No. 5 A d e rc o try m a g lo m e r a ta ( B r a d y ) , X 198; USC 6 4 8 ; Hypo t y p e , USC No. 1 157. 6 A m m o b ac u lltes f o l i a c e o u s (B rad y ) form a r e c u r v a E a r - l a n d , X 7 4 ; a , B id e v ie w ; b , o p p o s i t e s i d e ; USC ^76; H y p o ty p e , USC No. I I 5 8 . 7 A m m o b ac u lites f i l l f o r m i s E a r l a n d , X 8 7; USC 1035; H y p o ty p e , USC No. 1 159. 8 A m m om arginulina e n s l s W ie s n e r, X 8 3 ; USC 528; Hypo t y p e , USC No. 11551 9- T e x t u l a r i a w i e s n e r i E a r l a n d , X 145; USC 6 4 9 ; H ypotype, USC No. 116 1 . 10 T e x t u l a r i a w i e s n e r i E a r l a n d , X 145; USC 6 4 9 ; H ypotype, tJSC No. 11621 285 PLATE IV 1 C ribrostom oides arenacea (H eron-A lien and E arlan d ), X 128; a , i n v o l u t e s i d e ; b , e v o lu t e s i d e ; c , edge v iew ; USC 500; H ypotype, USC No. 1154. 2 C rib r o s to m o id e s u m b ilic a tu lu m s o l d a n i i ( E a r l a n d ) , X 103; a , edge v iew ; b , e v o lu t e s i d e ; USC 689; Hypo t y p e , USC No. 1155,. 3 C r ib r o s to m o id e s u m b ilic a tu lu m s o l d a n i i ( E a r l a n d ) , X 207; edge view ; USC 5 8 9 ; Hypotype, USC No. I I 5 6 . 4 Trochammina quadrlcam erata E ch o ls, n. s p ,, X 221; a , v e n tr a l view ; b, edge view ; c , d o rsa l view ; USC 500; H olotype, U SN M No. 5 A d erco try m a g lo m e r a ta (B ra d y ), X 1 9 8; USC 6 48 ; Hypo t y p e , USC No. 1157. 6 A m m obaculites f o l i a c e o u s (B rady) form a r e c u r v a E a r - la n d , X 7 4 ; a , s i d e v iew ; b , o p p o s ite s i d e ; USC 476; H ypo typ e, USC No. I I 5 8 . 7 A m m obaculites f i l i f o r m l s E a r la n d , X 87; USC 1035; H ypotype, USC No. 1159. 8 A m m om arginulina e n s i s W le sn e r, X 83: USC 528; Hypo t y p e , USC No. I I 6 0 . 9 T e x t u l a r i a w i e s n e r i E a r la n d , X 145; USC 649; H ypotype, USC No. I l 6 l . 10 T e x t u l a r i a w i e s n e r i E a r la n d , X 145; USC 649; H ypotype, tJSC too. 1162. i 285 286 > . .Nit-.-i-.'jlSiVSSi PLATE V 1 P s e u d o b o liv in a a n t a r c t i c a W ie sn e r, X 128; USC 6 5 8 ; H ypotype, USC No. 1 1 6 3 . 2 B i g e n e r ln a m ln u tls s lm a E a r la n d , X 147; USC 645; H ypotype, USC No. 1164. 3 S p lro p le c ta m m ln a b i f o r m i s (P a rk e r and J o n e s ) , X 147; USC 497; H ypotype, USC No. I I 6 5 . 4 S p lro p le c ta m m ln a f i l l f o r m ! s E a r la n d , X 168; USC 645* H ypotype, USC No. I l 6b . 5 S p lro p le c ta m m ln a a f f . S. f l l l f o r m l s , X 147; USC 647 H ypotype, USC No. 1167. 6 S p lro p le c ta m m ln a a f f . S. f l l l f o r m l s , X 147; USC 647; fry p o ty p e, tJSC too. 1168. 7 S p lro p le c ta m m ln a s u b c y l l n d r l c a E a r la n d , X 147; USC 473 ; Hypo ty p e , tJSC No. I l b 9 . 8 E g g e r e l l a p a r k e r a e (U c h lo ), X 118; a , > a p e r t u r a l view ; b , s i d e view ; USC-693; H ypotype, USC No. 1 1 7 0 . 9 V e r n e u i l i n a m ln u ta W ie sn e r, X 127; a , a p e r t u r a l view ; b , s i d e v iew ; t/SC 649; H ypotype, USC No. 1 1 7 1 . 10 G a u d ry in a p a u p e r a ta E a r la n d , X 147; USC 708; H ypotype,' USC No. 117£ r 11 C onotrocham m lna b u l l a t a (H o g lu n d ), X 108; a , edge v iew ; b , d o r s a l view ; tTSC 500; H y potype, USC No. 1173* 12 C onotrocham m lna b u l l a t a (H o g lu n d ), X 111; a , edge v iew ; b , d o r s a l view ; USC 647; H ypotype, USC No. 1174. 287 288 PLATE VI 1 Gonotrochammina k en n ettl E choIs, n, s p ., X 207; a , d orsal view* b, edge view; c , v en tra l view; USC 6 3 8 ; H olotype, U SN M No. 2 Conotrocham m lna ru g o s a ( P a r r ) , X 125; d o r s a l view ; USC 548; H ypotype, USC No. 1175. 3 Conotrochammlna altern an a Earland, X 159; a , v e n tra l view; b , d o rsa l view; tirS C 544; Hypotype, U SC No. 1176. 4 Conotrocham m lna sp . B, X 157; a , d o r s a l view ; b , edge view ; c , v e n t r a l view ; USC 680; H ypotype, USC No. 1177. 5 Conotrocham m lna sp . C, X 159; a , d o r s a l view ; b , edge view ; c , v e n t r a l view ; USC 604; H ypotype, USC No. 1178. 289 290 PLATE V II / 1 P o rta tro c h a m m ln a w i e s n e r i ( P a r r ) , X 168; a , v e n t r a l v iew ; b , d o r s a l view ; c , edge v iew ; USC 500; Hypo t y p e , USC No. 1179*- 2 P o rta tro c h a m m ln a w i e s n e r i ( P a r r ) , X 168; a , v e n t r a l v iew ; b , edge view ; c , d o r s a l view ; USC 500, Hypo ty p e , USC No. 1180. 3 P o rta tro c h a m m ln a w i e s n e r i ( P a r r ) , X 149; a , edge view ; b , d o r s a l view ; c , v e n t r a l view ; USC 503; H ypotype, usc No. ii8 i. _ 4 P o rta tro c h a m m ln a a n t r a c t i c a ( P a r r ) , X 135; a , edge v iew ; b , d o r s a l view ; c , v e n t r a l view ; USC 673; Hypo ty p e , USC No. 1182. 5 P o rta tro c h a m m ln a a n t a r c t i c a (P ari*), X 106; edge view ; P e n n e ll S ank, ftoss S e a , A n t a r c t i c a ( J . P . K e n n e tt c o l l e c t i o n ) . 6- P o rta tro c h a m m ln a a n t a r c t i c a ( P a r r ) , X 106; edge view ; P e n n e ll Bank, R oss S e a , A n t a r c t i c a ( J . P. K e n n e tt c o l l e c t i o n ) . 7 P o rta tro c h a m m ln a a n t a r c t i c a ( P a r r ) , X 106; edge view ; P e n n e ll Bank, R oss S e a , A n t a r c t i c a ( J . P . K e n n e tt c o l l e c t i o n ) . 291 292 PLATE V III 1 P o r ta tr o c h a m m ln a e l t a n i n a e E c h o l s , n . s p . , X 154; a , v e n t r a l v ie w ; b , e d g e v ie w ; c , d o r s a l v ie w ; d , o p t i c a l s e c t i o n ( d o r s a l ; ; USC 5 0 3 ; H o lo ty p e , USNM No. 2 P o rta tro c h a m m ln a e l t a n i n a e E c h o l s , n . s p . , X 210; a> v e n t r a l v ie w ; b , ed g e v iew ; c , d o r s a l v ie w ; USC 6 3 8 P a r a t y p e , USNM No. 3 Trooham m ina t r i c a m e r a t a E a r l a n d , X 159; a , v e n t r a l v iew ; b , e d g e v ie w ; c , d o r s a l v ie w ; USC 500 ; Hypo t y p e , USC No. I I 8 3 .. 4 Trocham m lna pygm aea H o g lu n d , X 131; a , v e n t r a l v ie w ; b , e d g e v ie w ; c , d o r s a l v ie w ; USC 6 4 8 ;, H y p o ty p e , USC No. 118 4 . i'i. t * < W V > ( , «V * . A ’ /V PLATE IX 1 Trooham m lna i n c o n s p i c u a E a r l a n d , X 299; a , v e n t r a l v iew ; b , edge v iew ; c , d o r s a l v ie w ; USC 7 0 8 ; Hypo t y p e , USC No. 1185. 2 Trooham m lna l a b l a t a U c h lo , X 274; a , v e n t r a l v iew ; b , ed g e v iew ; c , d o r s a l v iew ; USC 544; H y p o ty p e , USC No. 1186. I 3 Trooham m lna s u b c o n l c a . P a r r , X 1 8 3 ; a . d o r s a l v iew ; b , edge v iew ; c , v e n t r a l v iew ; USC 6 4 7 ; H y p o ty p e , USC No. 1187. 4 Trooham m lna q u a d r l l o b a H o g lu n d , X 1 8 3 ; a , v e n t r a l v iew ; b , d o r s a l v iew ; c , ed g e v ie w ; USC 6 4 7 ; Hypo t y p e , USC N o . .1 1 8 8 . 5 Trooham m lna o o n io a E a r l a n d , X 233; a , v e n t r a l v ie w ; b , d o r s a l v ie w ; c , edge v iew ; USC 6 4 8 ; H y p o ty p e , USC No. 1 189. J 295 296 W : '$M i i m&M W i $ i ' $ PLATE X Trooham m lna g l a b r a H e ro n -A lie n an d E a r l a n d , X 183; a , d o r s a l v ie w ; b , ed g e v ie w ; c , v e n t r a l v iew ; USC 5 °9 j H y p o ty p e , USC No. 1190. Trooham m lna g l a b r a H e ro n -A lie n an d E a r l a n d , X 1 5 6 ; a d o r s a l v ie w ; b , ed g e v ie w ; c , v e n t r a l v iew ; USC 6 3 0 ; H y p o ty p e , USC No. 1 191. Trooham mlna m a lo v e n s ls E a r l a n d , X 247; a , d o r s a l view b , ed g e v iew ; c , v e n t r a l v ie w ; USC 6 7 5 ; H y p o ty p e, USC No. 1192. Trooham m lna d l s c o r b i s E a r l a n d . X 234: a , d o r s a l view ; b , ed g e v iew ; c , v e n t r a l v ie w ; USC 648; H y p o ty p e, USC No. 1193. Trooham m lna s o r o s a P a r r , X 162; a , v e n t r a l v iew ; b , d o r s a l v ie w ; c , e d g e v ie w ; USC 6o4; H y p o ty p e , USC No. 1194. 298 * * * \ • ' f ' t V PLATE XI 1 Trooham m lna a f f . T, c o m p a cta, X 210: a , v e n t r a l v iew ; b , ed g e v ie w ; c , d o r s a l v iew ; USC 6 4 8 ; H y p o ty p e , USC No. 1195, 2 Trooham m lna com paota P a r k e r , X 184; a , v e n t r a l “v iew ; b , e d g e v ie w ; c , d o r s a l v iew ; USC 5 0 3 ; H y p o ty p e , USC No. 1196. 3 T r l t a x i s sq u a m ata J o n e s and P a r k e r , X 110; a , v e n t r a l v ie w ; b , e d g e v iew ; c , d o r s a l v iew ; USC 6 2 4 ; H y p o ty p e, USC No. 1197. 4 T r i t a x i s in h a e re n s (W ie sn e r), X 1 3 2 : a , v e n t r a l view ; b , edge view ; c , d o r s a l view ; USC 647; H ypotype, USC No, 1198. 5 Trocham m ina m u l t l l o c u l a t a H o g lu n d , X 228; v e n t r a l v ie w ; USC 54 4; H y p o ty p e , USC No. 1199. 6 Trooham mlna i n t e r m e d i a R h u m b ler, X 126; a , v e n t r a l v iew ; b , d o r s a l v ie w ; USC 569; H y p o ty p e , USC No. 1200. 299 300 PLATE X II 1 "M i l l o l i n e l l a " s p . , X 93; a , s i d e v ie w ; b , o p p o s i t e s i d e ; c , to p v iew ; USC 503; H y p o ty p e, USC No. 1201. 2 C a s s i d u l l n a s u b g lo b o s a B ra d y , X 120; a , s i d e view ; b , edge v iew ; USC 500; H y p o ty p e, USC No. 1202. j 3 C a s s i d u l l n o i d e s o r a s s a ( E a r l a n d ) , X 8 2 ; USC 675; Hypo- j t y p e , USC No. 1 2 ^ 4 C a s s ld u lin o id e B p a r k e r l a n a (B ra d y ), X 103; a . to p v iew ; — | b , s i d e v iew ; USC 65&; H y p o ty p e, USC No. 1204. 5 F u rs e n k o in a e a r l a n d ! ( P a r r ) , X 101; a , to p view ; b , s i d e v iew ; USC 500; H y p o ty p e, USC No. 1205. 6 P u rs e n k o in a f u s l f o r m i s (W illia m s o n ), X 101; a , to p v iew ; b , s i d e v iew ; tJSC 6 7 9 ; H ypotype, USC No. 1206. 7 P u r s e n k o in a f u s l f o r m i s (W illia m s o n ), X 99; s i d e view ; i USC' 6 7 9 ;"H y p o ty p e, *JSC No. 1207. 8 A n g u lo g e rin a e a r l a n d l P a r r , X 55; USC 674; H ypotype, | USC No. 1208. i , | 9 B u lim ln a r o s t r a t a B ra d y , X 167; a , s i d e v iew ; b , to p J v iew ; USC b 8 0 ; H y p o ty p e, USC No. 1 2 0 9 . 10 B u lim ln a a c u l e a t a d 'O r b ig n y , X 55; USC 679; H ypotype, USC No. 1210. ! 11 B o l i v i n a p s e u d o p u n c ta ta H oglund, X 113* USC 6 3 8 ; | H y p o ty p e, USC No. 1211. | 12 B o l i v i n a d e o u s s a ta B ra d y , X 125; a , to p v iew ; b , s i d e view ; USC b b 2 ; H y p o ty p e, USC No. 1212. 301 302 PLATE X III P u l l e n l a s im p le x R h u m b le r, X 1 0 5 i a , s i d e v ie w ; b , e d g e v ie w ; USC 5 0 2 ; H y p o ty p e , USC No. 1213. P u l l e n l a s u b s p h a e r i c a P a r r , X 100; a , s i d e v ie w ; b , ed g e v ie w ; USC 6 8 5 ; h y p o ty p e , USC No. 1214. P u l l e n l a o s l o e n s i s F e y lin g - H a n s s e n , X 179; a , s i d e v ie w ; b , e d g e v ie w ; USC 6 4 6 ; H y p o ty p e , USC No. 1215. N o n io n e lla l r l d e a H e r o n -A lie n a n d E a r l a n d , X 102, a , s i d e v ie w ; b , ed g e view ; c , o p p o s i t e s i d e ; USC 4 6 0 ; H y p o ty p e , USC No. 1216. N o n i o n e ll a b r a d i l (C hapm an), X 124; a , s i d e v ie w ; b , ed g e v ie w ; c , o p p o s i t e s i d e ; USC 5 0 3 ; H y p o ty p e , USC No. 1217. A s tr o n o n lo n e c h o 1 s i K e n n e tt, X 104; a , s i d e v ie w ; b , ed g e v ie w ; USC 500; H y p o ty p e , USC No. 1 2 1 8 . M e lo n is c f . M. a f f i n i B ( R e u s s ) , X 9 5 ; a , s i d e v ie w ; b , ed g e v ie w ; USC 544; H y p o ty p e , USC No. 1219. 303 304 $$7 i PLATE XIV E l l o h e d r a w e d d e l l e n s i s ( E a r l a n d ) , X 219; a* v e n t r a l v ie w ; “ b , ed g e v ie w ; c , d o r s a l v iew ; USC 528; Hypo t y p e , USC No. 12 2 0 . E p o n ld e s tu m ld u lu s (B r a d y ) , X 196; a , v e n t r a l v iew ; Id, ed g e v ie w ; c , d o r s a l v iew ; USC 528; H y p o ty p e , USC No. 1221. E p o n ld e s s p , , X 230; a , v e n t r a l v iew ; b , ed ge view ; c , d o r s a l v ie w ; USC 6 3O; H y p o ty p e , USC No. 1 222. B u c c e l l a t e n e r r i m a (B a n d y ), X 4 3 ; a , v e n t r a l v iew ; b, ed g e v ie w ; c , d o r s a l v iew ; USC 685; H y p o ty p e , USC No. 1223. N u t t a l l d e s u m b o n lfe ra (C ushm an), X 84; a , v e n t r a l v iew ; b , ed g e v ie w ; c , d o rB a l v iew ; USC 513; H y p o ty p e, USC No. 1 224. 305 306 ? !? S ii& . » ) !¥ * * .A •■?* ' l ' V/»; , .* .• k M % •* „ « ;. •M -V j PLATE XV j 1 O r i d o r s a l i s s p . , X 168; a , d o r s a l v ie w ; Id, e d g e v iew ; c , v e n t r a l v ie w ; USC 6 8 2 ; H y p o ty p e , USC No. 1225. i 2 O r i d o r s a l i s s i d e b o tt o m i ( E a r l a n d ) , X 9 1 ; a , d o r s a l v ie w ; b , e d g e v ie w ; c , v e n t r a l v ie w ; USC 4 6 2 ; Hypo t y p e , USC No. 1226. 3 O r i d o r s a l i s t e n e r a ( B r a d y ) , X 9 1 ; a , v e n t r a l v iew ; b , edge v ie w ; USC 1074; H y p o ty p e , USC No. 1227. 4 E p i s t o m l n e l l a e x lg u a ( B r a d y ) , X 103; a , v e n t r a l v iew ; b , d o r s a l v ie w ; USC 1074; H y p o ty p e , USC No. 1228. 5 Q y r o id in a s u b p l a n u l a t a E c h o l s , n . s p , , X 173J a , v e n - t r a l v iew ; b , edg e v ie w ; c , d o r s a l v ie w ; USC 6 8 0 ; H o lo ty p e , USNM No. 307 308 M r 3 * y?‘• i s v r ' ' "/'V '.w PLATE XVI 1 V a l v u l i n e r i a l a e v i g a t a P h le g e r and P a r k e r , X 149; a , v e n t r a l view ; b , edge v iew ; c , d o r s a l view ; USC 685; H ypotype, USC No. 1229. 2 C i b ic i d e s l o b a t u l u s (W alker and J a c o b s ) , i r r e g u l a r fo rm , X 8b ; USC 1074; H ypotype, USC No. 1230. 3 C i b ic i d e s b r a d l i (T o lm a c h o ff), X 40; a , d o r s a l view ; b , v e n t r a l view ; c , edge v iew ; USC 6 5 6 ; H ypotype, USC No. 1231. 4 C i b ic i d e s g r o s s e p u n c ta t u s E a r la n d , X 4 l ; a , v e n t r a l view ; b , edge v iew ; c , d o r s a l view ; USC 6 5 6 ; H ypotype, USC No. 1232. 309 PLATE XVII j • j 1-23 M a r t i n o t t i e l l a m i l l e t t i (Cushman) m ic r o s p h e r ic form s 1 1 ,1 2 1, a p e r t u r a l view , X 24; 12, s id e v iew , X 12; USC 462 2 ,1 3 2, a p e r t u r a l v iew , X 24; 13, s id e v iew , i X 12} USC 462 1 ' j 3*14 3* a p e r t u r a l v iew , X 24} 14, s id e view , X 12} USC 462 j 4 a p e r t u r a l v iew , X 24} USC 462 5 ,1 5 5, a p e r t u r a l v iew , X 24} 15* s id e view , j X 12} USC 462 !" " " 8 l o n g i t u d i n a l s e c t i o n , X 18} USC 552 10 s id e view , X 12} USC 462 11 s id e view , X 12} USC 462 m egalosp.heric form s 1 6 ,1 6 6 , a p e r t u r a l v ie w , X 24} 1 6, s id e view , j X 12} USC 462 1 j 7*17 7* a p e r t u r a l v iew , X 24} 17* s id e view , X 12} USC 462 9 l o n g i t u d i n a l s e c t i o n , X 18} USC 462 | 18-23 s id e v ie w s, X 12} USC 462 j 24-46 M a r t i n o t t i e l l a a n t a r c t i c a (P a r r ) I m ic r o s p h e r ic form s i j . 24 l o n g i t u d i n a l B e c tio n , X 18} USC 699 i 35*42 3 5, s id e v iew , X 12} 4 2 , a p e r t u r a l view , X 24} USC 699 311 3 6 .4 3 3 6 , s i d e v ie w , X 12; 4 3 , a p e r t u r a l v iew , X 24; USC 6 9 9 37 s i d e v ie w , X 12; USC 1028 38.44 38, s i d e v iew , X 12; 44, a p e r t u r a l v iew , X 24; USC 6 99 3 9 .4 5 3 9 , s i d e v ie w , X 12; 4 5 , a p e r t u r a l v iew , X 2 4; USC 699 46 a p e r t u r a l v iew , X 24; USC 1028 jn eg alo s p h e r i c form s 25 l o n g i t u d i n a l s e c t i o n , X 18; USC 708 2 6 -2 9 s i d e v ie w s , X 12; USC 1028 3 0 ,4 0 3 0 , s i d e v ie w , X 12; 4 0 , a p e r t u r a l v iew , X 24; USC 708 31 s i d e v ie w , X 12; USC 725 32 s i d e v ie w , X 12; USC 1028 3 3 ,3 4 s i d e v ie w s, X 12; USC 708 4 l a p e r t u r a l v ie w , X 24; USC 1028 313 R E F E R E N C E S 314 REFERENCES A g e r, D. 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B ., 1957* T rocham m inidae and c e r t a i n L i t u o l i d a e ( F o r a m in if e r a ) from th e R e c e n t b r a c k i s h - w a te r se d im e n ts o f T r in i d a d , B r i t i s h W est I n d i e s : S m ith so n ia n M isc. C o ll. v . 134(5)* p . 1 - 1 6 . .S h c h e d r in a , Z. G ., 1958, On th e F o r a m in if e r a fa u n a o f th e K u ril-K am c h atk a T ren ch : T rudy I n s t . O keanol. Akad. Nauk SSSR, v . 27, P . 161-179. . , 1964, The f o r a m in if e r a n fau n a o f th e e a s t e r n s e c t o r o f th e A n t a r c t i c , i n S o v ie t A n t a r c t i c E x p e d .t I n f o r m a tio n B u l l . , v . 1, p . 125-127* E l s e v i e r P u b l. Co. S h is h k e v is h , L. J .* 1964, The d i s t r i b u t i o n o f f o r a m i n if e r a i n c o re s from th e n o r th e r n S c o t ia A rc, S c o t ia S ea: New York U n iv ., u n p u b l. Ph.D . d i s s e r t a t i o n , 128 p . Simpson, E. H., 1949* Measurement o f d iv e r sity : Nature, v. I63, p. 688. S v e rd ru p , H. U ., 1941, The i n f l u e n c e o f b o tto m to p o g ra p h y on ocean c u r r e n t s , i n A p p lie d M ech an ics, T heodore von Karman A n n iv e rs a ry Volume, p . 6 6 -7 5 . S v e rd ru p , H. U.* Jo h n so n , M. W ., and F le m in g , R. H ., 1942, The o c e a n s : P r e n t i c e - H a l l , Englew ood C l i f f s , N . J . , 1087 p . U ch lo , T ., 1960a , E co lo g y o f l i v i n g b e n th o n ic F o r a m in if e r a from th e San D iego, C a l i f o r n i a a r e a : Cushman Found. Fo- r a m i n i f e r a l R e s. Spec. P u b l. 5* p . 1 -7 2 . _ _ _ _ ________ , 1960b , B e n th o n ic F o r a m in if e r a o f th e A n t a r c t i c Ocean: S e to M arine B i o l . L ab. S p ec. P u b l. 12, p . 3-20. 323 U c h io , T.*. 1 9 6 0c , P l a n k to n ic f o r a m i n i f e r a o f th e A n t a r c t i c O cean: S e to M arine B i o l . L ab. S p ec. P u b l. 11, p , 1 -9 . U .S . Navy, 1957* O c e a n o g ra p h ic a t l a s o f t h e p o l a r s e a s , P a r t 1, A n t a r t i c a : H.O. P u b l. n o . 705* 70 p . Van d e r P l a s , L ., and T o b i, A. C ., 1 9 6 5* A c h a r t f o r ju d g in g th e r e l i a b i l i t y o f p o i n t c o u n tin g r e s u l t s : Am. J . S c i . , v . 2 6 3, p . 8 7 -9 0 . ..................... W a lto n , W. R ., 1952, T e c h n iq u e s f o r r e c o g n i t i o n o f l i v i n g F o r a m in if e r a : C o n t r ib . Cushman Found. Foram . R e s ., 3 , p . 5 6- 6 0 . W a rth in , A. S . , J r . , 1934, F o r a m in if e r a o f th e R oss S ea: Am. Museum N o v i t a t e s 721, p . 1 -4 . W ie s n e r, H ., 1931* D ie F o r a m in if e r e n : D e u tsc h e S u d p o la r E x p e d itio n 1901-1903* v . 20 ( Z o o l ., v . 1 2 ), p . 53-1& 5. W o lff, T .j i 9 6 0 , The h a d a l com m unity, an i n t r o d u c t i o n : D eep- Sea R e s e a r c h , v . 6 (2 ), p. 9 5 -1 2 4 . Wood, A la n , 1949* The s t r u c t u r e o f th e w a l l o f t h e t e s t i n th e F o r a m in if e r a ; i t s v a lu e i n c l a s s i f i c a t i o n : Q u a rt. J . G e o l. Soc. London, v . 1 0 4 (4 1 4 ), p . 2 2 9 -2 5 5 . AP P E NDI X 324 325 * f TABLE 5*— Occurrence of rare species. Agglutinated foraminifera occurring in five samples or less and calcareous forami nifera occurring in only one sample are excluded from Table 2 if they do not occur at relative frequencies greater than 2 percent in any benthonic assemblage. These species and their occurrences are listed below. Agglutinated Foraminifera S p ecies USC S ta tio n Numbers Ammobaculoides cylindroides 712, 528 Ammoflintina trihedra 6j2, 6o4 Astrammina rara 658 Astrorhiza triangularis 672 Conotrochammina sp. A 680, 569, 574, 1068, 503 C. sp. B 647, 574, 6o4 CribrostomoideB scitulus 679 Dendrophrya ereeta 652, 516 Gaudryina ferruginea 686, 506, 648, 544, ^81 G. minuta 528, 649, 686 Haplophragmoides bradyi 617 H. cf. H. kirki 685, 676 Hemisphaerammina bradyi 500 Hippocrepina pusilla 658 Hippocrepinella crassa 712; 645 Hyperammina cylindrica 537; 647, 648, 604, 548 H. laevigata 648, 645, 6o4, 7° 0, 1069 H. laevigata var. A 537; T3& H. subnodosa 460 H. tenuissima 650, 624 Jaculella cf. J. obtusa 648, 728, 646, 607 Marsipella cylindrica 528 Nodosinum gaussicum 574, 548, 476 Pelosina distoma 544 P. variabilis 544, 652, 638, 658 Pseudobolivina sp. A 537, 1035, 646, 544 Reophax curtus 685, 539, 676 R. regularis 682, 497, 675, 676, 504 R. turbo 652, 649, 648, 1040 Saccammina sphaerica 686, 650, 651 Spiroplectammina subcylindrica 473, 476, 693, 712, 716 Textularla paupercula ' ~ 652, 651, 654, 657 Trochammina appressa 676, 504, 647 T. compacta 503 T. globigeriniformis 686 T. grisea 569 TABLE 5— Continued Calcareous Foraminifera Species Angulogerina earland! f. pauperata Astrononlon antarcticum Buliminella tenuata Dentalina cuvleri D. frobisherensis Discorbis translucens Ehrenbergina glabra Hanzavala complanata Heronallenla llngulata H. parva Keramospbaera murrayi Melonls umblllcatulus Quinqueloculina semlnulum Robertina wieBneri Rupertlna stabilis Uvigerina bifurcata USC Station Numbers 528 681 674 630 675 107I+ 685 107V 617 617 61+7 569 685 65!+ 500 5I+ I+ TABLE 6 SPECIMENS PER G R A M O F SEDIM ENT FORAM INIFERA 327 I * C alcareous N on-calcareous S ta tio n P lan k ton ic b en thon ic benthonic R adiolarian s 460 1720 340 8.8 20,000 467 1760 77 10.4 14,900 473 123 19.3 36 10,800 k j 6 2.0 1.80 48 15,900 481 0.48 0.0 25 17,600 486 0.75 0.0 64 890 497 0.0 0.0 13.0 498 0.29 5.2 , A -7 68 500 8.5 61 110 101 502 0.074 0.87 1.10 520 503 1.08 8.2 15.3 85 504 0.028 0.63 2.6 12.1 506 0.97 0.47 10.7 4lo 513 3300 121 21' 6.2 516 (0-5 cm)' 1.06 0.30 10.4 10.9 516 (40-45 cm) 1350 37 0.0 517 0.26 0.26 19.5 7-7 520 0.21 1.80 10.8 1.02 524 0.152 0.0 7.8 13.3 528 147 __ 35 32 49 533 0.0 0 .0 7.5 670 537 0.012 1.90 73 1560 539 0.52 5.6 30 280 544 1.07 6.3 193 2600 548 o .4o 0.0 37 2300 562 0.0 0.0 131 7300 569 6.5 3-2 7.8 370 574 0.0 0.0 4o.o 11,300 590 0 . 0 * 0 .0 0.0 66,000 607 0.0 0.0 91 6200 6l 4 2600 250 44 230 617 8500 i l l 2.0 618 0.0 0.0 6.0 10.0 622 4.80 .41 11.8 69 624 117 28 99 • 4200 630 48 37 78 897 638 0.27 0 .0 119 1110 649 0.182 .20 111 165 652 0.0 14.4 48 654 1.56 15.0 156 657 0.118 0.60 4.4 111 658 1.70 27 38 TABLE 6— Continued 328 Calcareous N on-calcareous S ta tio n P lankton ic benthonic benthonic RadiolarianE 659 0.39 0.0 31 99 672 7.1 2.8 32 5100 675 0.0 0.170 16.8 47 674 47 260 1.02 7100 675 0.77 39 6.4 650 676 0.085 5.8 0.90 3200 679 350 100 4.8 20,000 680 63 31 20 18,800 681 320 15.5 5.9 2800 682 1+200 1 + 7 0 2 .1 7400 685 2600 990 15.1 3300 689 7-9 1.20 29 10,700 695 150 15A 58 17,000 700 76 8.0 158 21,000 705 3.8 1.60 28 11,100 708 0.62 0.150 36 6700 712 0.0 0 .1 + 3 61 3100 716 0.86 0.36 27 16,000 725 3.4 2.7 15.9 11,600 728 o.oi+ 7 O.ll+O 7.4 12,800 756 0.1+2 0.1+2 9.9 13,200 1012 0 .0 0.0 3 .1 0 .0 AC 1016 0.01+3 0.43 1017 0.0 16.4 4.3 1021 0.0 0.0 9.9 1024 0.51 185 0-2 1028 1.18 710 1031 1.68 860 1035 270 0.55 270 10,000 io 4o 67 0.90 66 1220 1045 0.180 105 1046 13.6 0.0 13.6 390 1060 8 .1 0.0 8.1 1070 1062 (0-2 cm) 1.86 0.0 1.86 78 1062 (33-35 cm) 6.9 0 .1 + 1 + 29 990 1068 0.0 0.28 47 1340 1069 0.0 0.0 28 3900 . 1074 i960 0.62 22 1087 0.088 0.0 13.5 l 48o 329 TABLE 7 RELATIVE FREQUENCIES OF RADIOLARIANS Spongoplegma Spongurus D isc- H eloth olu s- S ta tio n antarcticum Sphaerids pylom aticus shaped Perom elissa 46o 1 6 5 10 55 467 2 10 8 14 50 473 2 8 9 12 50 476 2 9 7 11 53 481 X 7 7 9 59 486 2 13 . 14 17 36 497 0 1 2 9 53 498 1 1 1 16 47 503 1 10 21 27 31 516 15 24 9 17 22 517 23 27 6 9 • 13 524 . 23 21 6 13 21 528 11 46 8 7 14 533 1 17 20 14 26 537 3 26 15 19 20 544 1 16 10 23 30 548 1 12 14 10 49 562 11 14 5 26 16 569 5 6 9 23 20 574 2 11 6 19 39 590 X 7 11 17 23 595 X 9 16 13 30 6o4 2 17 9 20 31 607 2 15 10 16 . 29 618 43 31 1 8 7 622 26 38 6 11 4 624 4 16 10 10 44 630 638 5 3 14 9 18 15 13 45 31 646 4 15 14 14 25 647 6 15 16 22 24 654 3 5 13 20 45 672 1 7 5 9 60 674 X 1 X 23 57 675 X 1 X 25 56 676 X 1 1 21 55 679 X 3 1 18 57 680 X 5 2 17 5,6 681 1 5 2 14 60 682 2 8 4 12 52 685 X 3 1 23 57 689 1 8 7 10 5^ 694 5 , 7 7 18 52 TABLE 7— Continued 330 Spongoplegma Spongurus D isc- H eloth olu s- S ta tio n antarcticum Sphaerlds pylom aticus shaped P erom elissa 700 1 11 7 13 45 708 1 10 10 9 51 712 3 23 8 17 4o 716 2 10 9 19 4l 725 2 8 9 17 . 4o 728 X 8 12 15 45 736 X 6 4 15 60 .1016 44 27 2 0 0 1017 65 32 0 0 0 1021 51 33 2 2 4 1024 9 31 9 17 10 1028 4 34 8 15 18 1031 3 24 9 14 27 1035 1 16 15 10 38 1040 l 16 15 13 37 1045 73 21 X X 2 io 46 8 24 26 15 14 1060 2 11 13 20 32 1062 6 35 15 12 17 1068 1 12 11 13 48 1069 1 7 9 10 53 1087 1 18 14 11 26 331 TABLE 8 SEDIMENT PROPERTIES Percent Mean Sand and Diam. Standard Station Gravel Silt: clay (q>) Deviation Skewness Kurtosis 46o 3-9 3.17 6.59 2.05 .30 -.1 9 467 5.1 0.84 7.88 2.27 -.4 8 -.7 9 473 8.3 2.01 6.85 2.41 - 5 7 • 91 476 14.3 1.12 7.09 2.61 -.1 9 - 1.17 481 8.0 2.33 4.56 3.35 -.0 8 -.8 1 486 8.3 .4o 8 .4o 2.21 - 1.48 2.49 497 7.8 1.16 7.23 2.52 -.1 6 -1.05 498 .6 .67 8.02 2.30 -.45 - 1.29 500 27.2 .67 6.73 3.20 -.4 9 -.95 502 82.3 503 87.3 1.34 I.07 3.00 1.51 1.91 504 83.2 506 72.0 513 33.9 l 4 .o 4.71 2.83 -.6 9 -.2 9 516 5.1 .24 8.95 2.19 -I.7 1 2.46 517 4.8 . .27 9.00 2.03 -1.36 .88 520 3-9 .51 8.54 2.41 -1.03 .27 524 7.1 .56 8.25 2.57 -1.13 .71 528 56.2 2.58 4.26 2.75 .76 .44 533 1.1 1.20 7 .2 7 . 2.25 -.0 3 ' -1.58 537 53-1 .96 539 87.2 2.71 1.19 2.88 • 79 544 39-6 2.0 6 4.82 3.41 -.0 9 -.4 4 548 41.5 1.90 4.57 3-59 -.1 9 - 9 9 560 IB.5-' 4.23 5.64 2.16 .56 -.05 569 15.5 2.84 6.06 2.50 -.3 9 .54 574 24.8 1.39 6.26 3.15 -.8 6 .02 590 . . _ 23.4 1.19 7.41 -.4 1 -.4 8 595 4.6 1.27 2.07 6o4 45.4 1.57 4 .4l 3-73 -.0 8 -1.03 607 23.4 1.50 6.33 2.79 -.3 7 -.7 8 6l 4 • 51.3 2.15 t 6.65 618 3.6 0.19 9.23 1.98 -2.38 622 1.8 0.28 9.07 1.67 -I.5 0 3.07 624 57-1 I.63 3.74 3.43 .36 -1.16 650 76.7 5.16 638 7-3 1.58 3.35 -.2 1 -.7 1 646 7.4 .91 7.51 2.45 -.8 9 .69 647 32.2 1.13 5.72 3-39 -.2 9 -.9 3 649 45.7 2.93 4.56 2.89 .11 -r 35 650 24.4 4.89 5.35 2.12 .71 • 30 TABLE 8— Continued 332 .tation Percent Sand and Gravel Silt:clay Mean Diam. (< P ) Standard Deviation Skewness Kurtosj 654 16 .6 6.0 7 5 .4 1 2.0 2 • 59 .81 657 4 5 .7 6.90 4 .4 9 2 .1 0 .61 • 37 658 1 7 0 6.45 5-39 1 .9 4 .81 • 74 659 34 .8 672 68.2 1.33 3 .6 3 3 .1 1 .83 - .4 4 675 35.0 1.73 5 .5 0 2 .9 0 • - .0 3 - .2 9 674 35.0 3-55 4 .3 4 3.22 - .0 2 - .3 6 675 8 0 .8 2.95 1 .6 6 3.02 .89 . .44 676 72 .0 2 .9 3 1 .3 9 3.53 1 .0 4 - .0 1 679 5 4 .1 3.01 4 .1 8 ' " 2 .6 7 .50 .53 680 33 .0 3.4 9 4 .95 2.55 .28 .27 681 4 2 .4 1.10 4 .3 2 4.52 - .0 8 -1 .4 6 682 7 2.6 1.56 I .70 3.92 .87 ■ , - .6 0 685 67 .2 1.95 3.4 8 3.03 • 57 .01 689 22.5 1.50 6 .1 4 - 2 .9 1 .11 - 1.0 8 695 22.5 1.2 7 6 .4 3 2 .8 6 . - .3 5 - .7 9 700 1 5 .0 • 95 7.1 6 2 .6 1 - .2 9 - 1.1 6 705 1 0 .3 1.50 6 .9 0 2 .4 4 - .7 1 .65 708 2 .5 1 .2 1 7 .8 1 1 .9 9 - .2 5 - .6 0 712 5 0 .4 0 .8 4 4 .1 3 4.46 .01 - 1.50 716 28 .6 1.15 6 .1 3 3.17 - .1 3 -1 .1 0 725 4 1 .7 1.33 5.2 2 3.2 3 - .1 5 - .9 3 728 2 .3 0 .9 1 8 .0 1 1 .93 - .7 2 1.15 756 3 6 .1 0 .2 8 1 .54 1012 0 .4 9.32 - 1 .1 1 .29 1016 1 .6 0.2 4 9.3 2 1.65 - 1 .4 9 1.82 1017 • 3 0.31 9 .2 8 1 .5 3 - .9 8 - .0 9 1021 1 .7 0.37 8 .9 8 1.88 - 1 .1 7 •77 1024 2 .3 0.3 4 9 .0 1 1 .9 3 - 1 .3 0 1 .1 3 1028 6 .4 0.35 8 .6 6 2 .25 - 1 .0 3 - .1 8 lOJI 5 .2 o.4o 8 .5 8 2 .3 0 - 1 .1 3 .48 1035 3 .6 0.66 8.2 2 2 .0 9 - .6 3 - .6 3 1045 0 .3 0.16 9.5 8 1.35 - 1 .5 8 2 .3 0 10*46 6 .2 0.22 9 .0 1 2 .0 1 - 1 .4 7 1 .3 3 1060 0 .2 0.3 4 9 .0 7 1 .4 9 - .7 3 - .3 2 1062 .8 0.2 9 9 .2 1 1 .6 9 - 1.2 2 .70 1068 .5 0.46 8 .7 3 1..54 - .6 1 .01 1069 .6 1.13 7-9^ 1 .86 - .0 9 - .9 7 1074 8 5 .2 1.46 1087 4 .4 7.26 2 .4 3 .05 -1 .2 4 333 TABLE 9 STATION LOCATIONS AND SAMPLING DATA Sampling Depth Sample Position Range Sampling Interval ^ Station Lat.S Long.W (meters) Gear8- (cm) Preservative 46o 53°o6 ' 53 06 44°48' 44 44 2050 2159 c/mt 0-5 alcC 462 54 06 54 09 45 04 44 50 34o4 34o4 MT fmlG 467 55 03 55 02 44 38 44 27 3742 3596 c/mt 0-5 ale 473 55 56 55 56 45 07' 44 56 36l 4 3614 c/mt 0-5 ale 476 57 11 57 1^ 44 53 44 47 3382 c/mt 0-5 ale 481 58 05 58 10 44 56 44 47 2800 c/mt 0 -5 ...... • ale 486 60 07 60 06 45 14 45 24 5289 c/mt 0-5 ale 497 61 10 61 10 45 13 45 13 256 SC 0-2 ale 498 61 40 61 42 45 09 45 09 366 PG ale 500 62 06 62 07 45 12 45 13 489 490 PG ale ale 502 62 14 62 14 45 19 45 20 1250 1308 PG ale 503 62 14 62 l 4 45 20 45-19 897 1089 PG ale 504 62 14 62 l 4 45 20 45 22 1519 1556 PG ale 506 62 16 62 17 45 25 45 26 2160 PG ale 33^ TABLE 9— Continued, Sampling Depth Sample Position Range Sampling Interval ^ Station Lat.S Long.W (meters) Gear8 , (cm) Preservative 513 63015‘ 63 18 44°56* 44 53 3784 c/ mt 0-5 a le 516 66 28 66 26 45 42 45 44 4196 c/ mt 0-5 40-45 a le 517 66 26 66 23 45 45 45 49 4196 PG V a le 520 66 33' 66 29 •48 11 48 10 3722 c/ mt 0-5 a le 524 64 05 6k 06 49 o4 49 13 34o4 344o c/ mt 0-5 a le 528 63 03 63 03 49 09 49 10 2998 2937 PG a le 533 61 09 61 09 48 50 48 46 2754 2752 c/ mt 0-5 a le 537 60 k'l 60 1 + 5 48 02 47 58 2187 PG a le 539 60 25 60 25 47 23 47 22 551 569 PG a le 544 60 02 60 02 49 10 49 13 2621 PG a le 548 59 01 58 58 49 00 49 o4 3847 3861 c/ mt 0-5 a le 562 48 13 48 15 4o 26 4o 24 5587 D C _ 0-2 a le 569 56 04 56 04 27 28 27 26 1043 D C a le 57^ 55 H 55 13 24 10 24 05 4008 3978 c/ mt 0-5 a le 335 TABLE 9— Continued Sampling Depth Sample Position Range Sampling Interval ^ Station Lat.S Long.W (meters) Gear8 , (cm) Preservative 590 55°07' 55 07 26o01' 25 59 ca. 7690 c/mt 0-5 ale 595 55 52 55 51 2l + 52 2l + 1+8 58I +7 5710 c/mt 0-5 ale 6ol+ 58 27 58 26 22 22 22 20 1+61+5 4802 c/mt 0-3 ale 607 60 05 60 07 22 2k 22 17 1+187 ^193 c/mt 0-5 ale 6ll+ 61 05 61 05 26 02 26 03 3770 c/mt — ? 2 1 ale 617 61 59 62 00 27 1+0 27 1+0 3038 33^9 c/mt - ale 618 65 03 63 02 27 10 27 07 1+548 1+557 DC 0-2 ale 622 61 39 61 1+2 29 15 20 10 3737 c/mt ale 62k 60 21 60 22 29 30 29 30 2330 2360 c/mt 0-5 ale 650 59 53 59 52 27 1+2 27 1 + 1 + 121+1+ c/mt PB ale 658 58 35 58 3^ 23 51 23 55 51+17 5673 c/mt 0-5 ale 61+5 57 5k 57 **7 23 1+9 23 1+7 6167 DC 0-2 fml 6k6 57 52 57 52 2l + 00 23 56 6076 DC 0-2 fml 6if7 57 55 57 57 2l + 06 2l+ 18 1+1+93 DC 0-2 fml 336 TABLE 9— Continued Sampling _ Depth Sample Position Range Sampling Interval ^ Station Lat.S Long.W (meters) Gear8 , (can) Preservative 648 58°03' 58 o4 24°46» 24 47 2976 D C 0 fml 649 58 17 58 18 25 54 26 02 1841 D C 0-2 fml 650 58 19 58 20 26 06 26 09 1244 D C 0-2 fml 651 58 20 58 20 26 09 26 12 851 D C 0-2 fml 652 58 20 58 20 26 17 26 18 558 D C 0-2 fml 654PC 57 56 57 51 27 38 27 35 812 D C 0-2 fml 657 59 33 59 34 27 12 27 11 1171 1226 c / m t 0-5 fml 658 59 05 59 05 26 39 26 39 •659 D C 0-2 fml 659 59 05 59 05 26 38 26 38 805 P G ale 662 50 32 50 35 43 32 43 35 1272 1281 c/ m t 0-5 fml 672 54 57 54 57 38 22 38 21 3697 D C 0-2 fml 673 54 07 54 07 38 09 38 09 201 D C 0-2 fml 674 54 44' 38 04 531 D C P B ale 675 54- 44 38 o4 329 D C P B ale 676 54 47 38 01 ca. 750 D C P B ale 679 54 54 37 06 ca.1032 D C 0-5 fml 337 TABLE 9— Continued Sampling Depth Sample Position Range Sampling Interval , Station Lat.S Long.W (meters) Geara _ (cm) Preservative 680 51 f°58' 3 7 ° 5 9 . 1510 DC 0-2 i fml 681 55 01 55 05 38 00 38 01 1900 DC 0-5 fml 682 55 05 55 05 38 02 38 03 2924 DC PB ale 685 54 55 54 55 38 05 38 07 595 677 c/mt 0-5 fml 686 54 59 55 04 38 13 38 07 2196 2379 m/t fml 689 56 15 56 17 37 03 37 03 3468 c/mt 0-5 fml 693 56 53 56 5k 37 31 37 32 3138 c/mt 0-5 none 700 58 04 58 05 37 50 37 44 3166 3255 c/mt 0-5 fml 705 58 51 58 53 37 19 37 17 2928 2946 c/mt 0-5 fml 708 59 11 59 09 37 13 37 04 2818 2827 c/mt 0-5 fml 712 58 43 58 45 33 20 33 23 2983 3331 c/mt 0-5 fml 716 56 51 56 50 34 25 34 09 3144 3197 c/mt 0-5 fml 725 54 05 54 04 33 43 33 37 2714 2727 c/mt 0-5 fml 728 52 53 52 53 33 59 33 56 2855 2873 c/mt 0-5 none 736 53 02 55 02 37 4o 37 38 3056 3102 c/mt 0-5 fml 338 TABLE 9— Continued Sampling Depth Sample Position Range Sampling Interval ^ Station Lat.S Long.W (meters) Gear0 , (can) Preservative 1012 65°03f 47°o4 ' 4182 HC 0-2 1016 6L - 30 44 06 4515 HC DB fml 1017 64 01 4o 44 4542 HC 0-2 fml 1021 63 02 40' 55 4llo HC 0-2 fml 1024 61 58 4o 54 3484 HC 0-2 fml 1028 61 08 ,4o 11 3880 HC 0-2 fml 1031 60 19 38 50 3508 HC 0-2 fml • - 1035- 60 k2 60 39 54 55— 54 55 2679 2901 c/mt 0-2 fml 1040 60 3k 28 37 3206 HC 0-2 fml 1045 62 15 30 29 4787 HC 0-2 fml 1046 60 3k 60 52 31 08 31 06 3806 HC 0-2 fml 1060 60 25 60 26 3 3 C V l CM 3642 HC 0-2 fml 1062 61 42 34 58 3644 HC 0-2 55-35 fml 1068 59 01 34 00 3400 HC 0-2 fml 1069 59 01 37 09 2485 HC 0-2 fml 1074 62 05 39 15 2796 HC 0-2 fml 1087 60 4-9 49 25 2644 HC 0-2 fml 339 T A B L E 9—Continued Station Position Lat.S Long.W Sampling Depth Range (meters) Sampling Gear8 , Preservative*5 Samples Examined Only for Specimens Larger than 0.5 mm in Diameter 459 53°06* 44'’ 48* 2050 MT fml 55 06 44 44 2159 462 54 06 45 o4 3404 MT fml 54 09 44 50 34o4 472 55 56 45 07 3742 MT fml 55 56 44 56 3614 475 57 H 44 53 3382 MT fml 57 14 44 47 480 58 06 44 56 2800 MT fml 58 10 44 47 488 60 06 45 26 4721 PG fml 60 03 45 25 5280 505 62 i 4 45 22 1656 PG ale 62 15 45 23 1674 543 60 01 49 04 2906 c/mt ale t 60 02 49 09 2946 575 55 n 24 10 . 3978 ■ MT fml 55 15 24 05 4oo8 603 58 27 22 22 4643 MT fml 58 26 22 20 4645 606 60 05 22 24 4l l 8 MT fml 60 07 22 17 4l 4l aSampling gear: DC, double twin cores suspended from spreader bar; C/MT, gravity core attached to Menzies trawl bridle; SC, gravity core; MT, mud sample retained in Menzies trawl; PG, Petersen grab; HC, core attached to end of line during hydrographic casts; BT, mud sample retained in Blake Trawl. 3^0 TABLE 9— Continued Sample interval: PB, sample In plastic bag; length of core segment uncertain. Preservative: ale, alcohol; fml, buffered formalin. I TABLE 2 - RELATIVE ABUNDANCES OF FORAMINIFERA IN TOTAL FREQUENCIES CALCULATED SEPARATELY FOR PLAN! X * > 0 . 6 P E R C E N T P « P R E S E N T (T O T A L P O P U L A T IO N > 4 0 S P E C IM E N S ) S L O P E S S. O R K N EY S . SANDWICH TRENCH RIM S T A T I O N N U M B E R N K N O N N ® K * * • « « • « « « « « N ff O O in N t t t N t H lD lO O • • O fftO O O O lQ * ®|0|0«0 N « t — * t l - 0 e * * 4 0 N » 10 « n w » a 2 m Y n <r j ♦ o u v o n v u p t t V t t i D O V 638 846 648 974 604 607 D E P T H IN M E T E R S - 0> - < e o N O O « * N O N m m n m o o c n m «t m n w N O io o in o iv -------- C V M 10 IH 0 O I« O )N C lD 0 A lt 9 )n t N f*+ lfta N lA --< 0 < 0 t» K < 0 - - N N N N N N 10 * > £ 2 2 1 2 W » « « 4 o o - M ( n g n a M * — — —— — — » o - 3993 4 6 4 4 41 3 0 P L A N K T O N I C - B E N T H O N I C R A T I O O S N v n i n N n o t o O O l O f l O N S t - g t P O O N m - B © o g o o o O O O O p O p O O O 0 = 10 ♦ •> g * * 0 n m 10 e> r. S q 5 " 8 g t o " § g g .0 0 2 0 0 O O O P E R C E N T A G E C A L C A R E O U S F O R A M IN IF E R A 3.12 6.90 6.11 9.61 7.09 11.32 19.66 19.61 29.32 8.11 24.90 p p — — omi*>0»Nm<0< 0<0 • 2 * 8 * S J S & S S S S S & g g & S N N « N « d N a O n - 4 » g 3.96 3.13 4.91 11.70 13.37 14.49 S I M P S O N 'S D I V E R S I T Y I N D E X • v t f o i v i n a i B f • • 0 8 8 S 8 5 8 * ' 0 " 0><0 I D M O N J P - J - X j j ----- 10 N * — P » " o«0- O K O P L A N K T O N I C S P E C I E S G LO B IG ER IN A B U LL O ID E S 0. PACHYDERMA G. Q U IN Q U ELO B A G L O B IQ E R IN IT A O L U T IN A T A G. U V U L A X XX P 4^977 4R n ^ M M M X x ■ P t t X 1 1 4 p 4P p p p p 4P p p p p • P P PMP P«P 4? 7 > I P P P P p G LO B O R O TA LIA IN F L A T A 6 . S C IT U L A 6 . T R U N C A T U L IN O ID E S IM M A T U R E FORMS (M O S T L Y G. P A C H Y D E R M A ) X X X X • P P B P P BENTHONIC SPECIES CALCAREOUS HYALINE A N G U LO G ER IN A E A R L A N D I E P IS T O M IN E L L A E XIG U A ASTRONONION E C H O L S I B O L IV IN A P S E U D O P U N C T A T A B U L IM IN A A C U LE A TA ' X 2 4 II1717 9 5 6 3 3 1X12 3 13 17 1310 710 9 4 2 2 I X 1 X X 1 17332114 2 2 2 X X 8 1 1 2 7 4 X 1 X 3 2 4 11 I I X 2 X 2 2 X 8 8 1 16 1 X 2 X X I 2 X X 6 X 4 X X X CASSIOU LIN OID ES CRAS 8 A C. PARKERIANUS FISS U R IN A MARGINATA F. SEMI MARGINATA F U R 8 E N K 0 IN A E A R L A N D I 6 22381914 3 1 1 X 4 2 2 X X X X 1 3 2 612 1 1 I X X X 211 XI9 X X X 1412 6 212 I I F. FUSIFORMIS FLORILUS JAPONICA LAGENA D ISTOM A . L. ELONGATA O O L IN A A P IC U L A TA 12 9 1012 X 3 2 1 1 X X X X X 1 1 X X X X 2 X X 1 X P U LLE N IA 8 UBCARINATA BUCCELLA TENERRIMA EPO NIDES SP. A LAGENA Q UADRALATA OLAN O U LIN A A N TA R C TIC U M X X 1 1 X X X X 1 X X 1 X X X X X X . 1 X X 4 . X PULLENIA 8 UBSPHAERICA B U LIM IN A R OSTRATA CA8 SID U LIN A L A E V IG A TA C. LENS C. SUBGLOBOSA X X I 1 3 3 1 1 X X 2 3 XX X X X 1 X 4 i t s t x m r 3 6 9 1 X X X X I I 1 1 1 X *12 6X1’ I X 1 X X X X 1 2 - RELATIVE ABUNDANCES OF FORAMINIFERA IN TOTAL POPULATIONS OF THE SCOTIA SEA AREA. FREQUENCIES CALCULATED SEPARATELY FOR PLANKTONIC AND BENTHONIC POPULATIONS. X ■ > 0.6 PERCENT T « 0 -S CM. CORE 8E0MENT P ' PRESENT (TOTAL POPULATION > 40 SPECIMENS) B> 40*46 CM. CORE SEGMENT S L O P E S BASINS S . SANDWICH______ TRENCH R IM S. ORKNEY SCOTIA SEA WEDDELL SEA o 4 0 4 0 4 0 4 0 4 0 K«oem)N«wN<rNnno «»onoooon*«nn» mmnmmmmmoomo NON — AtPOOPPaO^ mn m n » m m m m * ♦ idtitumitv v«ioiiita« 9 1 0 1 0 W 4 0 + 4 0 4 0 4 0 ♦ + N 0-00 4 0 4 0 4 0 ONfO40-egfOOlftC££ N 4 0 4O040- + 4 0 W ++55?w 405nn° oo kknnCoo+S 2S?i:2?SSm2f58i!f5!:S!2S ••oooooooommmnmmwomn OOOtK OOCNO M 0 6 N 0 I4 0 - -NNIO mmoomatometN+OMN mmaiamr»mmmN*a>m« NAfDAMD- — NNNNNNIO mmo»ISP»t»»so« mig««00-Mugn*Nt — -SScuctim* »40K t^ S IDO- 1 0 4 0 < 0 1 0+ o 04+ 10 0 6 4 0 — IO + + ggSSgSSSE! 55888 SnSSSSSSS sSSRSRSnSSISSX^SSSSSS 5nm ?2o?-2S«8S8 SSSS3 ? S w ? sss? ? s5 » ? ? Nnoto omo^nNCiN-mKooO cyn-gnomooo OOOOOOOOOO ° l 5 5 S .lg r° |S 8 1 B woo o o ooo ir;ONoo-o>-nnNoo o-mn-oowo 1 0 ooo^“ •“ « ! 9 •§? O • ^ n s ; : ~ . - s s S. SS; > m -w-o 4 0 014-0 ttOOOOiOOONtfO 4 0 0 4 — — 01 0 1 0 0 4 f* 1 0 4 0 4 0 |0 " + 2 2 « D N 0 1 0 4 1 0 0 4 0 O I D * «*'— Nmo*o«iP-mmNO m}mmo-m-mmom»m NNOtsmONmOm jjmwg 4 0 1 0 — 0 4 -* 0 4 O N 0 4 N M + -‘ro + * •omm«»oo«HaiHi NntMP 5 ! 3®^33P:o»“ Nm58S!«!99t °® ♦•SSr.SfcBEi^SteSai^a ** •m mmmmrn* m-m« » • * 5 9 * : mm»m»i4 Niim rim M N M PNXB4B °mmS8?8,r',> ',,0><0 m » i o t- 2 • - « “ x S i ” “ "• n* -m m n 040- ONO ■•m toot-m«KOoo-*«* oo 0 6 9 1 0 0 1 “ on bon oom_momm».mm - ommmmm X X \x< P hhh X X ■ t X 1 1 4 p ^ P p p p p PP p p « PPPMPP<f> < P P > IP P P P 0 X t • > < P ( P p . P P 4 M 9 P ' P M P • X 4 P B 0 B I 4 M T P I T P P P X p p<Pp p p # # " 9 9 $ X P P X X X X • P P B P P X 1 1 0 4 7 7 6 P X 1 1 ■ 66 S 9 19 17 4 2 2 1 X X 2 2 2 X X 6 II 27 4 X 1X9 2 4 11 II X 2 X 2 2 X 8 8 1 16 1 X 2 X XI 2 X X 6 X 4 X X X 1 X 1 4 9 X 1 4 X X 2 9 1 2 1 26 92X X 2 2 2 P XX 6142127X16 X X 1 1 X X 1 1 1 X X X 211 XI9 X X X 1412 6 212 11 X 2 1 X 9 2 X 2 X X • X 1 X X • 1 X X X . 1 X X 4 , X X X 1 X 9 9 I I 2 9 XX X X 9 1 r * T 9 6 9 1 X X X X I I 1 V 1 1 X 2 X X X * « * X 9 Y 2 X 1 X 1 X '12 6X1 I X " 1 X X X X 1 i PULLENIA SUBSPHAERICA BULIMINA N08TRATA . CA88IDULINA LAEVIOATA I e . LENS ! C. SUB6L0B08A XXI 1 SB I I X X 2 3 X X X X X 1 X 4 1 2 8 2 X 3 X 8 2 11 X * 12 2 X 1 IX X X X I I I 1 1 X 1 X X X X 1 CIBICIDE8 LOBATULU8 IRREG. X 1 2 X XX X X EHRENBER6INA OLABRA X EILOHEDRA WEDDELLENSI8 2 21712288 2 1 4 XIO X 1 1 X X X 2 8 1 13 12 1 EPISTOMINELLA ARCTICA X 4 12 FI88URINA FIMBRIATA X X X XX , GYROIDINA SOLDANII X I I 1 1 X X 12 0. SUBPLANULATA X • 2 B 1 1 X ' 4 1 2 B X 1 1 ISLANDIELLA QUAORATA X X LAGENA MERIDIONALIS __ X X X X X LIN8ULINA TRANSLUCIOA X X NONIONELLA IRIOEA 12 I8I6I822S 2 X B I 1 PARAFISSURINA LATERALI8 X X 1 X X X VALVULINERIA LAEVIGATA 1 2 1 BOLIVINA OECUSSATA X 8 X 1 LAGENA NEBULOSA X I f — X ORIOORSALI8 8I0EB0TT0M SI 1 4 1 1 2 X i PARAFI88URINA CURTA X X 1 , i P. FUSULINIF0RMI8 X 2 X X PU LLE N IA S IM P LE X X 1 1 X X X 2 I2 X « UVI8ERINA CF. U. ATTENTUATA X X DENTALINA ITTAI X X EPONIDES TUMIOULUS X X S S 2 X X 3 OOLINA MELO X X X ASTRONONION ANTARCTICUM X CIBICIDES GR0SSEPUNCTATU8 1 1 X 1X321 X 1 1 LAGENA ASPERA X X XX STAINFORTHIA COMPLANATA XXI SX 1 X IX GLABRATELLA MINUTI38IMA XX OYROIDINA ORBICULARIS 1 1 X NOOOSARIA OOLIOLARIS X ; ORIDORSALIS TENERA 1 1 0. SP. A 1 X X i SEABROOKIA CF. S. EARLANDI X X XX SPHAEROIDINA BULL0IDE8 2 • EHRENBERGINA TRIGONA 1 FISSURINA SP: A. X X XX 1 F. SP. B. X X X - ISLANDIELLA ISLANDICA X PULLENIA OSLOENSIS X • x 1 i i MELONIS POMPILIOIDES 1 NUTTALIDE8 UMBONIFERA 1 1 1 1 0RID0RSALI8 MARCIDA X HERONALLENIA WILSONI X X DENTALINA COMMUNIS LARVA X FISSURINA ANNECTENS X X X X X h V NONIONELLA 6RADII 1 X 22 X X RUPERTINA STABILIS X CIBICIDES BRADII , X X C . L0BATULU8 1 PATELLINA ANTARCTICA X X ------, --------- ------------------in----- 8 8 8 1 X ‘ 18 6 X I IX 8 X XX « I 4 XK> X I I X X X X I I I I I X I X X X X I X X X X 4 8 I 13 18 I 8 X X 8 44 X 8 X X IS 887 4 8 X X I X I JLS X 8 II 8 xss X X 4 8811 I 18 X X 4 I 8 8 X X 18 I I X 4 8 8 I 8 X 8 1 X 8 IIII 8 X 8 I I 89 X X I X X X X XX I 8 X X X X X 8 I8 X 8 I I I I X S 8 I X X 8 I I X 8X 8 8 I I X X X I I XX SX I X I X IS I X I XXIX I X X XX X X 4 4 X I 8 8 X 9©/ 88 84 11 I X X X 8 X X X X X X X X I 8 I 8 X I I I I X X 1 4 1 1 8 X X X IS X I8M S7IBMN X X I X 8 8 X X X X I X I x xe 8*1 X X ■OLIVINA D ECUSSATA LAGENA NEBULOSA X S X 1 X X X 0 R I0 0 R S A L I8 8 ID E B 0 T T 0 M 8 I 1 4 1 1 2 X P A R A F I8S U R IN A C U R TA X X 1 P. F U 8 U L IN IP O R M I8 X 2 X X P U LLE N IA S IM P L E X X I I X X X 212 X • U V IQ E R IN A CF. U. A T T E N T U A T A X X O E N TA LIN A I T T A I X X EPONIDES TU M ID ULU 9 X X S S 2 X X 9 OOLINA MELO X X X ASTRONONION A N TA R C TIC U M X CIBICIDES Q R O S SEPU N C TA TU S 1 1 X 1X921 X 1 1 LAGENA ASPERA X X XX S TA IN FO R TH IA COMPLANATA X X 1 S X 1 X I X O LAB R A TE LLA M IN U T I3 8 IM A XX GYROIDINA ORBICULARIS 1 1 X NODOSARIA D O LIOLARIS X O R ID O R SA LIS TE N E R A 1 1 0. SP. A 1 X X SEABROOKIA CF. S. EARLANDI X X X X S PH A ER O ID IN A B U LLO ID ES 2 • EHRENBERGINA TRIGONA 1 FISSURINA SP; A. X X X X 1 F. SP. B. X - X X IS L A N D IE L L A IS LA N D IC A X P U LLE N IA O SLO E N S IS X 1 X 1 • 1 MELO NIS POMPILIOIDES 1 N U T T A L ID E S UMBON IFER A 1 1 1 1 0 R ID 0 R S A L I8 MARCIDA X H ERONALLENIA W ILSO N I X X D E NTA LIN A COMMUNIS LA R VA X FISSURINA A N N E C T E N S X X X X X NONIONELLA BR A D II 1 X 2 2 X X RUPER TINA S T A B ILIS X '' CIBICIDES BRADII X X C. LOBATULtiS 1 P A TE LLIN A A N TARCTICA X X MELONIS A F F IN IS 1 1 C ERO BERTINA ARCTICA X X ROBERTINA W IE S N E R I X MELONIS UMBILIC ATU LU S • 1 U VIG ERINA ASPERULA PARAFISSURINA VENTRICOSA ANGULOGERINA EARLANDI F. PAUPERATA C A 8 8 ID U L IN 0 ID E S PORRECTUS M I8C . LA GEN OIOS PORCELANEOUS CYCLOGYRA IN V O LV E N S X KERAMOSPHAERA MURRAYI X M ILIOLINELLA SUBROTUNDA X PYRGA MURRHINA QUINQUELOCULINA' SEMINULUM X ■ TRILOCULINA TRICAR IN A TA X X UNIDENTIFIED M IL I0 L I0 8 X ^ 1 I ' 2 '* . .ji ..'t 't’r . . . i . . * * X X X X 2 12 X 1X321 X I 2 X X 3 I I X 8X 2 X X X X X 3 X II I « I I X X X XII XX 3 X I X I X 13 I X I XXIX I X X XX X X 4 4 X I 2 2 X S3 34 I I I X X XSX X X XX X X • I 2 X I I I I X X 1 4 1 1 2 X X X X it x i tosmam xx I X 22 XX X X I X X I X X Xt SSI I I X X X I 3 4 X X X XXX X X X S X X MISS T 3 3 1 X XX I X X T A B L E 2 - R E L A T I V E A B U N D A N C E (C O N T .) F R E Q U E N C IE S C A L C U L X • > 0 .6 PE R C E N T P« PRESENT (TO TA SLOPES S. G E O R G IA S. O R K N E Y S OF F O R A M IN IF E R A A T E D S E P A R A T E L Y L POPULATION > 40 SP! S. S A N D W IC H X IN TC F O R P •CIMENS) TRENCH >TAL L A N K ' r im S T A T IO N N U M B E R IIN N « <0I0<O<0<0W i M * l t s a o a i H N * « h « N « n o •>0)Oi4OOOOin*«inm<s vvtom m m ttininiQ O O oo N ( K . * t » . O e « * « O K n o o n a n n n n a N * * * 638 646 645 574 604 607 D E P T H IN M E T E R S u,. - « - # O N O O » » S O N n n n n o o i N * N n n i t s o n * N i i « — — -MMIO <OI0OOI4AAAAf>-4OlQN n * N n t M A M n - -----N N N N N N I0 • m n - io a A ^ ^ .m t s w ia « m o jo jr m » ♦ ♦ ♦ * ^ o » mwCOAOO — N u e H IA N V --------— — — (Y rJ ro * 3545 6076 6167 3993 4644 4130 P L A N K T O N I C - B E N T H O N I C R A T IO O h N c n n N i t o t o o - - n o ” “ —♦M el O A O «IO K A *»-tf>N O O O « im -io io o « D o O o q o o q q q o o q o - n + a a J J o n i o i o a n ^ - now t o * o o o O O P ' 9 0 • o ‘q O O MOO o o OO O PERCENTAG E CALCAREOUS FO R A M IN IFER A 3.12 6.90 6.11 S.6I 7.03 11.32 13.68 1 5 .6 i 23.32 8.11 24.90 * 4 n i i ) « a « 0 a N t t « — 4" a a j o n A a ii> A A O » n « - s i n o t O N h * a w o in « m n q -in -a < o o < 0 A <0 N N o is e o N n d io j- o o io 3.96 3.13 4.91 11.70 13.37 14.49 S IM P S O N 'S D IV E R S I T Y I N D E X 00I9I09IW M 0 0I ° 2 JS * 2 2 2 " r ^ " o x ° 10 IQ —10 ^ C M rO NO NA A—♦ —X jj —“ *> » n Fi n o « - 0 X 0 CALCAREOUS AGGLUTINATED DOROTHIA SP. A EQGERELLA NITENS E. PARKERAE VAR. A KARRERIELLA BRADYI K. CATENATA X 1 3 7 1 • X K. DEFORMIS K. NOVANGLIAE M ARTINOTTIELLA MILLETTI RUOLOAUORYINA ' INEPTA 2 2 X 6 • NON-CALGAREOUS BATHYAL AMMODISCUS CAflNUS AMMOFLINTINA AROENTEA CRIBROSTOMOIDES . ARENACEA C. JEFFREYS! HAPLOPHRAGMOIDES CAftARIENSIS X I X 2 XX X 9 X X 9 1 ■ 1 X I 7 1 X I I 3 2 6 3128 2 X 9 1 2 6 1 2 1 1 2 X 6 8 18 1222X91 X X 2 1 9 2 II X X 1 8 10 1 3 4 7 X 2 MILIAMMINA ARENACEA M. LATA PORTATROCHAMMINA ANTARCTICA P. WIESNERI PSEUOOBOLIVINA ANTARCTICA 46 1 X 1 1 X XX 52 1 X X I S I X 2 1 6 2 X 80941 2 3298 X 3 6 X 1 6 8 II 6 6 XX 21X4 8 1 7 2 6 1 8 1 3713 2 X 2 7 7 8 6222612 4 1 6 4 3 XI4 1 XX 3X12 14 X 3 1 X I 2 12 30 81431 116 11412 REOPHAX SUBFUSIFORMIS SPIROPLECTAMMINA BIFORMIS TEXTULARIA EARLANDI TROCHAMMINA MALOVENSIS T. INTERMEDIA 1 XX 1 . 1 10 X 1 1 XX 1 2 XX 1 1 2 2101 X I X I I I 1 X 128 3 X 6 1 XX 3 2 7 II I I II T. . MULTJCAMERA1TA. VERNEUILINA . EUROPEUM V. MINUTA I I XX X 9 1 I I I I X X X 1 613 1 18 1 1 X I X 1 1 8 3 1 2 f 8 6 7 7 1 7 X 6 B X X X ABYSSAL AMM06ACULITES AGGLUTINAN8 A. F0LIACE0U8 A. F0LIACE0U8 F. RECURVA AMMOLAGENA CLAVATA EN8IB____________ '________ j X X X 6 2 2 X X X X X 2 2 X I X X 2 1 1 X 2 1 X 1 1 9 I 1 X 7 X 2 1 XX 1 . X 1 X 1 2 1 1 X X 1 3 2 - RELATIVE ABUNDANCE FREQUENCIES CALCUL X« > 0 .6 PERCENT P * PRESENT (TOTA S L O P E S RfilA S. ORKNEY S OF FORAMINIFERA IN TOTAL ATED SEPARATELY FOR PLANK L POPULATION > 4 0 SPECIMENS) i S. SANDWICH TRENCH ‘ RIM POPULATIONS OF THE SCOTIA SEA AREA. [TONIC AND BENTHONIC POPULATIONS. .. • T » 0 * 8 CM. CORE SEGMENT B* 4 0 - 4 5 CM. CORE SEGMENT BASINS SCOTIA SEA WEDDELL SEA D -BNN D BBBN 0 n a o a io n* aN a Nm n o n a o n o o o O K i * c n n « a * » ato a n mm a o o n o C | g S . » « h O O * « t O N n n a n o n a n a a N a a a 838 646 645 574 604 607 O N n a - a n n o a a N a N a a a a - a a N < 0 < 0 N N e * 5 a o o o a a r - N N n n N N a ♦ » * a * m a a N N N o o N N N N N o o a » a n »NawN a - n * on a - N a - - a a n n - n n - ? S * £ S 2 2 a a o o o o o o o o n n n g S a a o a a 3 O0N0I A **IB£ - - N N * 0 0 0 O O M 0 0 A 0 N 0 O n N n a a a o N a a a N a o i a a N n a a o > N a - - a a N N a --NNNMNNIO a m m - n a n a a - a a a m n « u ano>N a -----------NN tO * 5545 6076 6167 3993 4644 4130 ■ANaNoaOaniNnnO n- w4 0 4 O 0 s o N * a o n « n % N i i 5 . t i n a i t . t i t a t t — N a o « a « m N n n n N n m n n c iiN N m n n N N n n n n a a N N N n o a a o N N a a a o a a a a a n a a - o a o - a N N * * » N M # a * a - ; a t — n - n n « f n t t t n n n t t w w f t kiwnwn M *>0*0 - -* B N o » o » * h « t - « ! ; o o o N « - » « O 0 O O O o o q q o q o q q q o - n a n n a a o N n m n N « - ; h o n « o « o o q o o o ■qoi ■ o ' g o o .002 0 0 OOO n q N o o - f f i - a n N o o o =**<0Oo o n o » «IN *N -N (i « - T «~ ,on - o o o ' ' ® 9 q o o ° n 0 0 S 2 2 !2 0 0 ®f* n o a a a . ^ . e S « r ~ S q q ” - •*,B B N - O 1 0 00) — 0 > 2 £ n " n « * n n i0 i o « A B N * * a a n — — o n n n N n o o o “ * 2 £ 2 ,'®:2 ," 2 " 8 ® n t - N « o * ONNaeNO i o a n n q - n - a a q a a a , i» ‘n o n a o n n o n jja s i g 3.86 3.13 4.91 11.70 13.37 14.49 4.88 6.50 20.55 23.85 7.56 15.79 17.00 23.90 17.18 9.22 9.33 12.98 16.93 26.32 16.23 14.54 8.82 10.43 9.05 6.06 (OB t O " B I O B B B B B - B N 0)0 B B B B C t * It N O PJ 0)0 0> C 4 N , M l l i t t O fb O M l) - n a a a 1 0 NaW o n o a a a o a n n o K o 1 0 IO — 19 * tt himosJ A - J - x JI— n n * - n n n o a - OXO a a a a o o a - a a x o o o - a N a o o 0) B p) W *■ o n -nON ® O n - n o a a N a n “ o a a a a a X 1 37 1 ■ X 1 2 X X X X 2 1 2 2 X a ' « X X 12 XX (2 1 1 XI 7 1 X II B 28 8126 2 X 3 1 2 8 1 2 1 1 2 X 8 8 1 8 1222X91 X X 2 1 3 2 1 1 X X 1 510 1 34 7 X 2 XXXXIX 1 1X2X1 1 X X 1 <X K 1 1 62X 60341 2 3268 X9 6 X 1 8 811 6 6 XX 2 1 X 4 8 1 7 28 1 B 137132X2 7 7 8 8222812 4 1 8 4 3 XI4 1 XX 3X12 14 X 3 1 XI 2 12 30 81431 118 11412 1 X 1 2 1 a . 1 1 2 XX 1 1 2 2101 XI XI I I 1 X 125 3 X 8 1 XX 9 2 7 1 1 1 1 II X X l i l t X X X 1 813 1 IS 1 1 XIX 1 183 1 2 ( 8 87 717 X8 8 XX X 2 1 X 1 XXII 1 1 2 2 1 X 1 1 X X X a s s X X X X X 22 X IX X2 1 1 XS 1 X 1 1 3 1 1 X 7 X 2 1 XX 1 X 1 X 1 2 1 1 X X 1 X 3 X 4 X 22 1 2 1 X <4 IX 2 239 9 19X I X 2 2 1 X X X 4 1 3 X 4 6 X X 1 P X 1 X 1 X X 1 > 3 1 11X 2 P X 2 4 8 1 1 XX XX 7 8 2 3 8 2 X 4 A B Y S S A L AMMOBACULITES A 0 0 L U T IN A N 8 X X X 22 X 1 X T X A. FOLIACEOUS • 2 2 1 X X 2 1 X 2 X 1 A. FOLIACEOUS F. RECURVA X X 1 2 1 1 1 X AMMOLAOENA CLAVATA X X X 4 XX 3 AMMOMARGINULIN A ENSIS X 1 1 a 1 X 1 X 1 2 X X BATHYSIPHON DISCRETA X X X 1 X X X B. GRANULOSA X X X A X X 4 B. RUSTICUM X X X X X B. SP. B X X X 1 X X 4 1 BIGENERINA MINUTISSIMA X i 4 4 X CONOTROCHAMMINA K E N N E T TI i p 6 24 4 24 1 2 C. RUGOSA X 1 8 8 X C. SP. A. X CRIBROSTOMOIDES SPHAERILOCULUS MEGALOSPH. 2 3 2 C. SPHAERILOCULUS MICROSPH. 10 2 ' 1 8 9 2 e 29 s 10 2 7 3 C. SUBGLOBOSUS X 4 1 10 1 2 X P X 2 1 8 9 9 26 2 1 C. UMBILICATULUS SOLDANII XX 4 1 2 1 2 6 . 3 CYCLAMMINA PUSILLA 8 C. TRULLISSATA CYSTAMMINA ARGENTEA XX X X 1 X 2 X C. PAUCILOCULATA X 2 X 4 X 1 1 EGOERRELLA PARKERAE VAR. B 1 X 1 1 3 . P 1 3 17 7 GLOMOSPIRA CHAROIDES 1 X XX X 8 12 1 4 2 1 '2 2 XWII 8 8 X 282321 G. GORDIALIS X I I 2 1 X 1 X X 1 3 X 1 1 1 GAUDRYINA PAUPERATA X I XX 1 2 1 2 8 X HORMOSINA DAVISI 8 1 X 1 H. GLOBULIFERA X X 1 P 1 XX 1 2 1 X HYPERAMMINA SP. A 1 1 X 2 1 1 KARRERIELLA APPICULA RIS . * X 1 X MARTINOTTIELLA ANTARCTICA X s 3 1 2 2 P 2 I 1 1 X 1 2 MILIOLINELLA SP. X X X P XXXI X NOOELLUM MEMBRANACEA X X X X 1 1 X 1 X 2 1 3 PLACOPSILINELLA AURANTIACA 8 X 8 X X X 2 1 > PSAMMOSPHAERA FUSCA ' 1 8 1 X ISX 1 1 1 1 2 X 1 REOPHAX NODULOSA X X 1 X R. SP. A 10 1 X 8 2 2 IS • 18 P 2 1 X 4 1 18 4 2 1 X R SP. B X 1 1 X 4 XX X 3 X X SACCAMMINA TUBULATA 1 1 1 1 XX 21 X 1 6 X X X 1 SPIROLOCAMMINA TENUIS 1 P X X SPIROPLECTAMMINA FILIFORMIS X 2 14 2 3 1 S. AFF. S. FILIFORMIS X X X 1 X 2 2 TEXTULARIA WIESNERI T 1 1 8 2 4 2 1 XIO14322 X 6 7 X X TRITAXIS INHAERENS 1 9 2 X 6 P 6 8 10 9 isis a T. SQUAMATA X • XX X 2 1 1 1 X TROCHAMMINA AFF. T. COMPACTA X X X 1 X X 2 X T. CONICA 1 4 2 X X X 3 X 2 X 1 1 4 T. DISCORBIS 2 2 X 4 X X 2 X X T. INCONSPICUA X 1 X l i e 12 IS X X 4 2 3 T. LABIATA 4 1 1 1 X 1 1 1 X X X 1 3 3 T. OUADRILOBA X 1 • XX 1 1 1 8 7 1 X 1 7 3 T. SOROSA , 1 X 8 X X 1 1 2 6 22 2 1 1 3 2 T. SUBCONICA X X 1 2 X N O N - D E F I N I T I V E ( X 2 2 X * 1 X T X 4 X 22 1 P X 1 X 1 X I 2 1 X X I 1 X I X 1 1 2 1 X 1 * 1 4 X 1 9 X X 1 2 1 1 1 X I X 2 3 3 3 1 1 X 2 P X 2 4 3 1 X X X XX 3 I S X 1 X 2 1 XX X X X 1 1 3 1 X 1 X 1 2 X X 2 1 XX X 4 1 3 X 4 6 X X 7 2 2 9 2 2 X 4 * X 1 X X X X X X X X X X X X 4 X X X X X 1 1 X X X X X X 1 1 X X 1 X X X 1 X X • 1 X I X I 1 X X 1 4 4 X • 1 X 1 P 6 24 4 24 1 2 . 1 3 3 X . 1 9 P 1 X X 4 4 X 1 8 3 X 2 2 X 3 X • 1 2 1 1 3 6 1 X 3 2 X 2 X 2 3 2 2 3 X 10 2 1 3 9 2 6 29 3 10 2 7 3 4 4 2172 I X 6 3 II 4 2 2 P 1 3 2 X 1 2 1 X X 4 110 1 2 X P X 2 1 8 0 926 2 1 212 3 4 2 4 3 410104 8 2 PI2 31 B226P PBOII 8 P 14 P 10 818 1 X 1 1 XX 4 1 2 1 2 6 3 7 617 137127 3 2 2 1 0 3 6 7 X 2 8 P 4 B82 2 4 HjflfHtl 1 8 1 1 P 6 1 1 2 12 X XX X X 1 X 2 X X XX 2 1 X 2 X 4 X 1 1 2 X X X 1 X I I 3 . P' 1 3 17 7 2 9 6 91122271718 9 610296 X X X X 8 1 2 1 4 2 1 2 2 XI4II 9 8 X 282321 XIO 7 1 3 1 2 11 4 3 8 4 X 1 82023 21 1 9 1 « 1 X > 1 1 2 1 X 1 XX 1 3 X 1 1 1 X 1 X 1 X X ‘l 3 1 X P 3 X 1 X 1 XX 1 2 1 2 8 X X X X 1 X X 2 1 2 X 2 2 1 3 1 X 1 P X 1 I P 4 3 X X X 1 P 1 XX 1 2 1 X X IX X X I X X 2 2 2 X X 1 1 P 1 1 1 X 1 1 X 2 1 1 * X 1 X 1 2X X 1 2 X 1 X s 3 12 2 P 2 1 1 1 X 1 2 X 1 6 2 9 9 1 4 9 7 1 9 9 8 X 8 1610414P PX X X X X X P XXXI X XX I I I 2 PP X X X X 1 1 X 1 X 2 1 3 X X X 1 X s X 8 X X X 2 1 X 13 12X11 II 2 X 1 8 8 3 2 X 1 1 X 1 1 s 1 X ISX 1 1 1 1 2 X 1 1 8 1 3 X X X 1 X 1 2 3 2 3 2 1 2 9823 I X I 4 I X X 1 X X X X 2 X XX X X 1 X s 2 2 16 618 P 2 1 X 4 1 IB 4 2 1 X X X 1 24 3 8 778 98 42 2 BI4I6P 3 1 1 P 1 3 1 P 2 2 X 1 1 X 4 XX X 3 X X 2 1 2 2 X 2 1 1 1 1 XX 21 X 1 6 X X X 1 2 3 2 2 1 32 2 XI 1 1 X 2 1 3 1 1 P X X X X XX 1 1 1 P P 1 X 2 14 2 3 1 1 2 1 X XX 2 X X 1 X 2 2 1 X X 2 X 1 7 1 1 32 42 1 XIO14322 X 6 7 X X 6 4 9 1 1 2 X 1 1 1 3X16 210 3 1 7 XX X 2 1 » 2 X 8 P * 8 8 10 9 1813 a 1 9 8 4 9 4 16X2 29 911 9 2 8 P 6 3 SP X X 1 1 X ■ XX X 2 1 1 1 X ■ 3 X 2 X X X X X X 1 X X 2 X X X 1 X 1 4 N X X X3 X 2 X 1 14 XX IX 2 11 1 X X . * 1 X ,1 2 2 X 4 XX2 X X X X 1 2 X X X 1 X 1 1 8 1 2 1 8X X 4 2 3 X X 2 X 77 72 1 X449 P 1 1 4 \ 1 1 1 X 1 1 1 X X X 1 3 3 2 11 14 1 1 X 1 X 1 1 t • XX 1 1 1 3 7 1 X 1 7 3 1 2 1 6 1 XXX 2 1 9 1 X S X X II 2 6 222 1 1 3 2 X 1 3 1 4 1 2 X X X 1 2 X 1 1 1 1 • X MARTINO T TIE L LA ANTARCTICA X s MILIOLINELLA SP. NODELLUM MEMBRANACEA PLACOPSILINELLA AURANTIACA PSAMMOSPHAERA PU8CA REOPHAX N 0 0U L 08A X X X s I S X X P X X I X ISX 1 X XXXI X 1 1 X 1 8 X X 1 1 1 X 1 X X 2 •X “- 2 1 3 2 1 X X 1 X R. SP. A R. SP. B 8ACCAMMINA TUBULATA SPIROLOCAMMINA TENUIS SPIROPLECTAMMINA FILIFORMIS . 10 1 X s X 1 1 2 218818 P 1 1 1 1 1 P X 2 14 2 1 X 4 X 4 X X X XX 2 1 X 1 8 X 2 1 IS 4 X 3 2 1 X 3 X X X X 1 X 1 S. AFF. 8. FILIFORMIS TEXTULA RIA WIESNERI TRITAXIS INHAERENS T. SOUAMATA TROCHAMMINA AFF. T. COMPACTA X X 7 1 1 9 X X X X 1 3 2 4 2 1 XIO 14 322 2 X S P XX X X 1 X 1 X 8 7 X X 88 10 9 2 1 1 1 X 2 X 2 2 Isis a X X T. CONICA T. DISCORBIS T. INCONSPICUA T. LABIATA T. QUADRILOBA 1 4 2 X I X ' 4 X 1 • 2 X X 2 X 1 1 3 1 1 1 X 1 1 X X I 1 XS X 2 4 XX2 12 I S X X 4 1 X X X - 1 3 7 X * X 1 14 X X 2 3 1 3 3 1 7 3 T. 30R 0S A T. SUBCONICA NON-DEFINITIVE ADEROCOTRYMA OLOMERATUM AMMOBACULITES FILIFORMIS AMMOSCALARIA TENUIMAROO CONOTROCHAMMINA ALTERNANS C. BULLATA 1 X s X 2 XX X X 7 X X XX X 2 S 1 2 X 1 1 X 8 X X 1 1 2 X 1 2 1 13102 X X 9 3 2 IS P 14 1X15 1 4 2732 3344I I S4P 8 222 1 X X X 21823 3 II X X X X X X X X I 7 8 108 8 II 6 3 2 2 X 1 X 1 1 2 X 8 4 8 8 1 3 2 9 8 8 1 2 1 2 1 CRIBROSTOMOIDES CONTORTUS C. UMBILICATULUS C. WIESNERI CYCLAMMINA CANCELLATA C. ORBICULARIS 2 X 1 X I X X X 2 X 3 3 3 X X X P X I I I X X X 1 X X X P X X I X XXXI 14X1 12 3 X X X 1 X XX 1 1 1 X X X 1 1 3 > X 8 1 2 K ' '! OPHRAOMOIDES PARKERAE H. QUADRATUS TROCHAMMINA QUADRICAMERATA HORMOSINA LAPIDI6ERA PORTATROCHAMMINA ELTANENSIS 4 XX 3 X , 4 7 2 X 7 X1 X X 13343 P 1 1 1 XX X 2 9 3 X X 8 5 II 625I0I6I03D824 P I I I 3 1 1983 3 5 2 3 2 5 X 3 1 2 X 1 8 4 I I 13 21 I I 1112 K) 4 6 2 8 34 54 38 3 2 1 1 1 3 X x 5 e REOPHAX ADUNCA R. DI8TANS R. LONQISCATISFORMIS R. OVICULA R. CF. R. ROSTRATA X X XX X X X X X XX X X X X I I X I I XXX X X X X X 1 XXX X X 1 I I X X X X X > X 1 X 1 1 R. SUBDENTALINIFORMI8 SACCORHIZA HEDRIX SPIROPLECTAMMINA TYPICA THURAMMINA EX. OR. T. ALBICANS T. PAPILLATA X X X . X X x s 1 5 1 2 X X 1 1 X P X XXX 1 X 1 2 XX X X XXX X X X X X X X X 1 2 X X X ) TOLYPAMMINA FRIGID A TROCHAMMINA OLABRA T. PYOMAEA T. TRICAMERATA VERNEUILINA MINUTA VAR. A 1 X 1 2 2 2 1 1 XX X • X 2 1 3 1 X 1 4 3 1 1 X X 1 4 2 2 P XX X 1 X 2 X I I I' 1 X 1 X I X X X 2 1 2 3 3 5 2 2 6 X 2 8 X 1 2 X X X 2 1 1 1 J X 4 1 X I x X X P XXXI •X“ XX I I I 2 PP X X X X 1 1 X 1 X 2 1 8 X X X 1 X 8 X 8 X X X 2 1 X 18 12X11 II 2 X 1 8 8 8 2 X 1 1 X 1 8 1 X ISX 1 1 1 1 2 X 1 1 8 1 3 X X X 1 X 1 2 3 2 8 2 1 2 9 3 2 3 I X I 4 I X X 1 X X X . X 2 X XX X X X 8 2 2 08 16 P 2 1 X 1 18 4 2 1 X X X 1 2 4 3 6 7 7 8 8 8 4 2 2 8I4WP 3 1 1 P 1 8 1 P 2 2 1 1 X 4 X X X 8 X X 2 1 2 2 X 2 1 1 1 1 XX 21 X 1 • X X X 1 2 3 2 2 1 3 2 2 X I 1 1 X 2 1 3 1 1 P X X X X X X 1 I I P P 1 X 2 14 2 3 1 1 2 1 X XX 2 X X 1 X 2 2 1 X X 2 X 1 7 1 1 3 2 4 2 1 XIO 14822 X 6 7 X X 8 4 8 1 1 2 X 1 1 1 3 XI6 20 3 1 7 XX X 2 1 9 2 X 6 P ' 6 8 0 9 1813 8 1 9 8 4 6 4 1 8 X 2 29 9i r 9 2 8 P 6 3 SP X X 1 1 X • XX X 2 1 1 1 X ■ 3 X 2 X X X X X X 1 X X 2 X X X 1 H 1 4 2 X X X 3 X 2 X 1 14 XX IX 2 11 1 X X , X 1 X ,i 2 2 X 4 XX2 X X X X 12 X X 1 X 1 1 6 1 2 1 6X X 4 2 8 X X 2 X 7 7 72 1 X 44 8 P 1 1 4 1 1 1 X 1 1 1 X X X - 1 8 3 2 11 14 1 1 X 1 X 1 I • XXI 1 1 3 7 1 X 1 7 3 1 2 1 6 1 XXX 2 1 8 X 8 X X 1 1 2 • 222 1 1 3 2 X 1 3 1 4 1 2 X X X 1 2 X 1 1 1 1 X 7 1 1 802 XX® 6 218 P X X 2 0 2 3 3 II X 1 1 9 8 8 X 1 4 8 2 7 7 4 0129 0 7 4 3 12 3 19 1717 8 7 3 • P4 2 0 0 1 X 2 X X 14 1X16 X XX X 2 X • 1 2 1 3 3X1 XXI X 1 1 9 X , 1 X X X 1 X X X 2 X 1 X XX XI 1 1 1 X X X 1 X 8 4 2 78 2 3 3 4 4 I I 8 4 P 7 • 08 • II 6 8 22 X 1 4 • • 2 1 33 2X 4 112. 1 27 1 X 4 0. • X 3 P 9 1 X X 8 2X3 3 6 X X X P X X X 1 14X1 1 2 8X X 1 1 3 X 244 32I22X 2 4 4 1 1 2 P 8 0 X X 1 1 1 X 1 X 1 X 3 X X X 9 1 1 X 1 X X X 1 X XX 1 XX X P XX 1 X 1 X 2 XX X X X X 1 1 6 1 2 1 1 < X 1 X X X X 4 X 1 XX 1 33 43 P 1 1 1 3 1 19 6 3 3 8 2 3 2 1 I I I 1 2 1 3 X 2 3 4 3 1 1 1 1 1 1 X 1 X XX 3 1 II X X X 2 328 X 3 1 2 1 2 1 3X8 XX 4X4 142 9 1 1 X • 3 X 1 1 3 8 X X X X XX X 1 X r 2 X 7 8 8 II 628018020924 P 6 4 I I 13 21 IIII1 2 0 4 6 2 • 34 84 36 X 8 6 X 1 1 6 8 4 6 8 7 4 7 II 8 2 9 7 0 19 7 1 9 1 1 1 1 X X 1 8 X X X XXX X X X X XI ■ X X XX X X X X X 1 X X X X X X ( X X X X X X X I I X X X X 1 XXX X X 1 X 1 1 XXXXX 1X1X2 1 21X1 1 1 X 2 X X X 1 1 1 1 X X 1 X 8 1 2 1 X 1 2 XX 1 2 X 1 1 X p X X X X X X X XX X X X X X X X XXX XXXXXI X X 1 X X X X X X X X X X XX X X 1 1 X P X X X I X X 8 1 X XXX X X X X X X X 1 X 2 1 8 1 X 1 4 8 1 X 1 XIX XX 2 2 1 1 1 3 X 1 XX 1 1 X 1 X X 1 X 2 X 2 1 1 X XI 42 2 P 1 2 8 382 2 8 X 2 3 X 4 8 X X 1 1236 97 2 1 16 1 1 XX X 1 2 X X 1 X 2 X X X 1 X 1 • 1 1 X X 1 1 x X 1

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Creator Echols, Ronald James (author)

Core Title Distribution Of Foraminifera And Radiolaria In Sediments Of The Scotia Sea Area, Antarctic Ocean

Degree Doctor of Philosophy

Degree Program Geology

Publisher University of Southern California (original), University of Southern California. Libraries (digital)

Tag Geology,OAI-PMH Harvest

Language English

Contributor Digitized by ProQuest (provenance)

Advisor Bandy, Orville L. (committee chair), Gorsline, Donn S. (committee member), Mohr, John Luther (committee member)

Permanent Link (DOI) https://doi.org/10.25549/usctheses-c18-601184

Unique identifier UC11359912

Identifier 6807179.pdf (filename),usctheses-c18-601184 (legacy record id)

Legacy Identifier 6807179.pdf

Dmrecord 601184

Document Type Dissertation

Rights Echols, Ronald James

Type texts

Source University of Southern California (contributing entity), University of Southern California Dissertations and Theses (collection)

Access Conditions The author retains rights to his/her dissertation, thesis or other graduate work according to U.S. copyright law. Electronic access is being provided by the USC Libraries in agreement with the au...

Repository Name University of Southern California Digital Library

Repository Location USC Digital Library, University of Southern California, University Park Campus, Los Angeles, California 90089, USA