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A SEDIMENT TRAP‐BASED STUDY OF PARTICLE FLUXES IN SAN PEDRO BASIN, CA:
REMINERALIZATION RATES OF ORGANIC CARBON AND BIOGENIC SILICA
by
Lisa Elizabeth Collins
A Dissertation Presented to the
FACULTY OF THE USC GRADUATE SCHOOL
UNIVERSITY OF SOUTHERN CALIFORNIA
In Partial Fulfillment of the
Requirements for the Degree
DOCTOR OF PHILOSOPHY
(GEOLOGICAL SCIENCES)
December 2009
Copyright 2009 Lisa Elizabeth Collins
Object Description
| Title | A sediment trap-based study of particle fluxes in San Pedro Basin, CA: remineralization rates of organic carbon and biogenic silica |
| Author | Collins, Lisa Elizabeth |
| Author email | lecollin@usc.edu; lisa.collins13@gmail.com |
| Degree | Doctor of Philosophy |
| Document type | Dissertation |
| Degree program | Geological Sciences |
| School | College of Letters, Arts and Sciences |
| Date defended/completed | 2009-10-09 |
| Date submitted | 2009 |
| Restricted until | Unrestricted |
| Date published | 2009-11-12 |
| Advisor (committee chair) | Berelson, William M. |
| Advisor (committee member) |
Douglas, Robert Fuhrman, Jed Alan |
| Abstract | A four-year sediment trap study, beginning January 2004, was conducted in San Pedro Basin, CA using moored traps located at 550 m and 800 m water depth. Two floating sediment traps were deployed seven times at 100 m and 200 m between November 2007 through June 2008. Fluxes of mass, particulate organic carbon (POC or Corg), calcium carbonate (CaCO₃), biogenic silica (bSiO₂), detrital, Corg/N, δ¹⁵N, and δ¹³C were determined.; Deep trap fluxes were examined along with climatological data to explore the relationship between the timing of physical forcing and particle deposition. Rainfall history, compared to detrital flux and patterns of δ¹⁵N and δ¹³Corg shows that the detrital fluxes and organic carbon fluxes into the sediment traps are marine-derived. There is no immediate pulse of terrestrially-derived sediment delivered to San Pedro Basin following winter rains.; Remineralization patterns were examined using flux data from all traps and the Martin equation, which predicts the downward flux of POC based on a power law relationship with a variable "b" that dictates the attenuation of the flux curve. Martin b values were highly variable with no seasonal pattern, although the average b value was 0.47 compared to the open ocean value of 0.86. This implies that given the same flux of POC from the surface, Corg is removed from San Pedro Basin more efficiently than in the open ocean.; Incubation experiments were performed on freshly captured particles from 100 m and 200 m to examine the affects of temperature, oxygen, depth, and season on remineralization rate constants for Corg and bSiO₂. Both Corg and bSiO₂ showed higher reactivity at 100 m versus 200 m and also higher reactivity at 25°C versus 10°C. Corg remineralized faster in the fall than in the spring and bSiO₂ showed the opposite trend. Remineralization rates for Corg did not change in oxic versus suboxic conditions, although for bSiO₂ they were different at 200 m and not at 100 m. Incubation data reveal detailed information of remineralization rates under changing oceanic conditions that can be incorporated into global circulation models to better predict how oceans will change with changing environmental conditions. |
| Keyword | geochemistry; geobiology; oceanography; biogenic silica; organic carbon; remineralization; San Pedro Basin |
| Geographic subject | basins: San Pedro Basin |
| Geographic subject (state) | California |
| Coverage date | 2004/2009 |
| 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 |
| Provenance | Electronically uploaded by the author |
| Type | texts |
| Legacy record ID | usctheses-m2738 |
| Contributing entity | University of Southern California |
| Rights | Collins, Lisa Elizabeth |
| Repository name | Libraries, University of Southern California |
| Repository address | Los Angeles, California |
| Repository email | cisadmin@dots.usc.edu |
| Filename | etd-Collins-3341 |
| Archival file | uscthesesreloadpub_Volume48/etd-Collins-3341.pdf |
Description
| Title | Page 1 |
| Contributing entity | University of Southern California |
| Repository email | cisadmin@dots.usc.edu |
| Full text | A SEDIMENT TRAP‐BASED STUDY OF PARTICLE FLUXES IN SAN PEDRO BASIN, CA: REMINERALIZATION RATES OF ORGANIC CARBON AND BIOGENIC SILICA by Lisa Elizabeth Collins A Dissertation Presented to the FACULTY OF THE USC GRADUATE SCHOOL UNIVERSITY OF SOUTHERN CALIFORNIA In Partial Fulfillment of the Requirements for the Degree DOCTOR OF PHILOSOPHY (GEOLOGICAL SCIENCES) December 2009 Copyright 2009 Lisa Elizabeth Collins |
