Page 1 |
Save page Remove page | Previous | 1 of 266 | Next |
|
small (250x250 max)
medium (500x500 max)
large ( > 500x500)
Full Resolution
All (PDF)
|
This page
All
Subset |
PHYSIOLOGICAL AND ECOLOGICAL CONSEQUENCES OF ENVIRONMENTAL
TEMPERATURE ON ANTARCTIC PROTISTS
by
Julie Marie Rose
A Dissertation Presented to the
FACULTY OF THE GRADUATE SCHOOL
UNIVERSITY OF SOUTHERN CALIFORNIA
In Partial Fulfillment of the
Requirements for the Degree
DOCTOR OF PHILOSOPHY
(MARINE ENVIRONMENTAL BIOLOGY)
May 2007
Copyright 2007 Julie Marie Rose
Object Description
| Title | Physiological and ecological consequences of environmental temperature on Antarctic protists |
| Author | Rose, Julie Marie |
| Author email | jrose@usc.edu |
| Degree | Doctor of Philosophy |
| Document type | Dissertation |
| Degree program | Biology |
| School | College of Letters, Arts and Sciences |
| Date defended/completed | 2006-03-31 |
| Date submitted | 2007 |
| Restricted until | Unrestricted |
| Date published | 2007-04-06 |
| Advisor (committee chair) | Caron, David |
| Advisor (committee member) |
Sullivan, Cornelius W. N[illegible], K[illegible] Fuhrman, Jed Alan Bakus, Gerald Joseph Kiefer, Dale A. |
| Abstract | The Ross Sea, Antarctica experiences one of the world's largest annual phytoplankton blooms at exceptionally low environmental temperature (-1.5-0.5oC). Chlorophyll concentrations during the bloom can exceed 15 mg l-1. Heterotrophic protists seasonally dominate biomass within Antarctic marine ecosystems, and function as important players in nutrient remineralization and carbon flow. However, these potential algal grazers do not prevent the formation of phytoplankton blooms in this ecosystem. Low temperature represents a constant potential limit on maximal growth of all Antarctic species, yet the effect of temperature on growth of heterotrophic protists is not well characterized. Existing data for growth rates and growth efficiencies of polar protists are conflicting. I investigated top-down control of algal and bacterial standing stocks at ambient Ross Sea temperatures through a literature review of temperature effects on protistan growth rate, laboratory experiments with cultured Antarctic protists and field estimates of grazing rates by assemblages of Antarctic herbivorous protists. Growth rates of phototrophs and heterotrophs at ambient Antarctic temperatures were universally low, but growth rates of heterotrophs appeared to be more strongly affected at low temperature than phototrophs. Maximum growth rates of herbivores were equivalent to algae at 20oC, but a quarter of maximum algal growth rates at 5oC. Growth and nutrient remineralization rates of Antarctic bacterivorous protists were low at 0oC and increased sharply with increasing temperature. Growth efficiency and nutrient remineralization efficiency by Antarctic bacterivorous protists were comparable to temperate conspecifics at all temperatures examined. Specific ingestion rates of Antarctic herbivorous protists in culture and in field assemblages were extremely low when compared with temperate congeners.; The estimated grazing impact of assemblages of Antarctic microzooplankton on phytoplankton standing stocks was low at four stations within the Ross Sea, even though microzooplankton abundance was high. These results suggest that strong constraints by temperature on top-down control (protozooplankton growth and grazing) in the Ross Sea may contribute to bloom formation. |
| Keyword | temperature; Antarctic protists; growth rates; growth efficiencies; heterotrophic protists; microzooplankton grazing |
| Language | English |
| Part of collection | University of Southern California dissertations and theses |
| Publisher (of the original version) | University of Southern California |
| Place of publication (of the original version) | Los Angeles, California |
| Publisher (of the digital version) | University of Southern California. Libraries |
| Type | texts |
| Legacy record ID | usctheses-m356 |
| Rights | Rose, Julie Marie |
| Repository name | Libraries, University of Southern California |
| Repository address | Los Angeles, California |
| Repository email | http://www.usc.edu/isd/libraries/services/ask_a_librarian/email/ |
| Filename | etd-Rose-20070406 |
| Archival file | uscthesesreloadpub_Volume29/etd-Rose-20070406.pdf |
Description
| Title | Page 1 |
| Full text | PHYSIOLOGICAL AND ECOLOGICAL CONSEQUENCES OF ENVIRONMENTAL TEMPERATURE ON ANTARCTIC PROTISTS by Julie Marie Rose A Dissertation Presented to the FACULTY OF THE GRADUATE SCHOOL UNIVERSITY OF SOUTHERN CALIFORNIA In Partial Fulfillment of the Requirements for the Degree DOCTOR OF PHILOSOPHY (MARINE ENVIRONMENTAL BIOLOGY) May 2007 Copyright 2007 Julie Marie Rose |
Comments
Post a Comment for Page 1
