Grantee Research Project Results
Denitrification in Permeable Continental Shelf Sediments on the South Atlantic Bight
EPA Grant Number: FP916364Title: Denitrification in Permeable Continental Shelf Sediments on the South Atlantic Bight
Investigators: Rao, Alexandra M.F.
Institution: Georgia Institute of Technology
EPA Project Officer: Lee, Sonja
Project Period: January 1, 2004 through December 31, 2006
Project Amount: $79,609
RFA: STAR Graduate Fellowships (2004) RFA Text | Recipients Lists
Research Category: Academic Fellowships , Fellowship - Oceanography , Fellowship - Aquatic Ecology and Ecosystems
Objective:
Denitrification rates and pathways are being investigated in continental shelf sediments of the South Atlantic Bight (SAB). This region, covering 90,600 km2 on the southeastern U.S. seaboard, is dominated by permeable, nonaccumulating medium- to coarse-grained sands. Despite low organic carbon content, recent measurements have demonstrated the presence of significant metabolic activity presumably supported by filtration of organic matter advectively transported into the seabed. The objective of this study is to contribute to our understanding of the fate of fixed nitrogen in permeable shelf sediments and the potential role of continental shelves in the marine nitrogen cycle.
Approach:
Sediment flow-through reactor experiments have been conducted with unamended seawater and 15N-labelled nitrate additions to constrain the nitrogen budget for these sediments. Preliminary results indicate that denitrification occurs in the presence of oxygen, probably within suboxic microenvironments and closely coupled to in situ nitrification. Coupled nitrification-denitrification may quantitatively consume regenerated nitrogen within the upper oxic zone of SAB sediments.
Supplemental Keywords:
fellowship, South Atlantic Bight, dentrification, continental shelf, sediments, marine environments, nitrogen cycle,, RFA, Scientific Discipline, Ecosystem Protection/Environmental Exposure & Risk, Oceanography, Monitoring/Modeling, Ecology and Ecosystems, aquatic ecosystem, environmental monitoring, dentrification, nitrification, continental shelf sediments, South AMerican Bight, ecosystem healthProgress and Final Reports:
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.