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Grantee Research Project Results

Grantee Research Project Results

Evaluation of Long-Term Change in Marine Zooplankton Community Function Using Amino Acid- and Taxon-Specific Isotope Analyses

EPA Grant Number: FP916350
Title: Evaluation of Long-Term Change in Marine Zooplankton Community Function Using Amino Acid- and Taxon-Specific Isotope Analyses
Investigators: Sheridan, Cecelia C.
Institution: University of Hawaii at Manoa
EPA Project Officer: Just, Theodore J.
Project Period: January 1, 2004 through December 31, 2007
Project Amount: $105,274
RFA: STAR Graduate Fellowships (2004)
Research Category: Fellowship - Oceanography and Coastal Processes , Academic Fellowships , Aquatic Ecosystems



The objective of this project is to understand long-term change in marine zooplankton community function. I will focus on observed variation in the zooplankton community at the Hawaii Ocean Time-series Station ALOHA (22.75º N, 175º W) and hypothesize that long-term change in these populations has occurred in response to climate-associated variation in nitrogen fixation.


My approach uses amino acid-specific isotope analysis (AA-SIA) to quantify the contribution of nitrogen fixation to zooplankton food web processes at Station ALOHA. This application exploits differences in the transformation of amino acid-specific nitrogen isotope signatures (delta15N) during predator-prey interactions. Amino acid delta15N that does not change during a trophic transfer can be used to establish food web nitrogen source, whereas amino acid? delta15N that changes substantially during a trophic transfer can be used to evaluate food web linkage. AA-SIA of target zooplankton collected from Station ALOHA will be used to track changes in the contribution of nitrogen fixation to the food web over time. In addition, this technique will be used to determine how zooplankton food web linkage and trophic transfer efficiencies vary in response to climate-associated perturbation of nitrogen source.

Supplemental Keywords:

fellowship, Hawaii, HI, ocean, zooplankton, nitrogen fixation, trophic transfer, food web, amino acid isotope analysis, taxon-specific isotope analysis, zooplankton community function,, RFA, Scientific Discipline, Air, ECOSYSTEMS, Ecosystem Protection/Environmental Exposure & Risk, Aquatic Ecosystems & Estuarine Research, climate change, Oceanography, Air Pollution Effects, Aquatic Ecosystem, Aquatic Ecosystems, Environmental Monitoring, Atmosphere, nutrient dynamics, oceanic phytoplankton, aquaculture, climatic influence, ecosystem monitoring, aquatic food web, anthropogenic impact, biogeochemcial cycling, global climate models, ecosystem impacts, amino acid isotope analysis, nutrient fluxes, carbon supply, climate variability, zooplankton

Relevant Websites:

2004 STAR Graduate Fellowship Conference Poster (PDF, 1p., 186KB, about PDF)

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The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.

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