USGS visual identity mark and link to main Web site at http://www.usgs.gov/

Assessing 
        Impacts of Anthropogenic Contaminants on Microbial Communities and Organic 
        Matter Composition in West Coast Estuaries Using Organic Geochemical Techniques: Elena B. Nilsen
Project Title: Assessing Impacts of Anthropogenic Contaminants on Microbial Communities and Organic Matter Composition in West Coast Estuaries Using Organic Geochemical Techniques
Mendenhall Fellow: Elena B. Nilsen, (650) 329-4799, enilsen@usgs.gov
Duty Station: Menlo Park, CA
Start Date: October 1, 2004
Education: Ph.D. 2004 (Ocean Sciences/Marine Geochemistry), University of California, Santa Cruz
Research Advisor: Bob Rosenbauer, (650) 329-4198, brosenbauer@usgs.gov; Kathy Kuivila, (916) 278-3054, kkuivila@usgs.gov
  Elena Nilsen

Project Description: Organic chemical contaminants pose an imminent risk to water quality and ecosystem health. Aquatic environments on the West Coast of the United States have been subjected to increasing pollution pressure due to exponential population growth over the past century. The detrimental effects of anthropogenic contaminant loading to the environment are relevant to ecosystem health and function, waste management, ground water resources, and human health. Understanding the fate and effects of various classes of organic contaminants is an issue of increasing concern to scientists and environmental managers.

One objective of this project is to develop and use sedimentary organic markers to trace accumulation of anthropogenic contaminants in select west coast estuaries. In addition, chemotaxonomic indicators will be analyzed to characterize changes in microbial biomass and composition of total organic matter accumulating in sediments through time. We will compare South San Francisco Bay, a highly urbanized estuary that receives urban runoff, agricultural runoff and wastewater discharge, and Elkhorn Slough (CA), a more pristine estuary that receives mainly agricultural inputs. We will contrast down-core microbial community structure and organic matter composition in the two estuaries through recent decades to centuries and correlate these records to the paleo-contaminant accumulation.

South 
        San Francisco Bay - salt ponds surround the southern reach of the Bay 
        and urban development encroaches on the watershed (image courtesy of the 
        San Francisco Estuary Institute)   Elkhorn 
        Slough, CA - main channel and marshlands visible in the background; cultivated 
        strawberry fields in the foreground.
South San Francisco Bay - salt ponds surround the southern reach of the Bay and urban development encroaches on the watershed (image courtesy of the San Francisco Estuary Institute).   Elkhorn Slough, CA - main channel and marshlands visible in the background; cultivated strawberry fields in the foreground.

Important results of this work will be 1) insight into environmental change in estuarine ecosystems on timescales relevant to human perturbations, 2) elucidation of effects of organic contaminants on microbial community structure and organic matter sources to West Coast estuaries, 3) differentiation between impacts of agricultural contaminants versus those of urban contaminants and 4) investigation of legacy pesticides and other persistent contaminants that have the potential to be remobilized from sediments as a result of planned salt pond restoration efforts in the South San Francisco Bay area.


Go back to Previous Profile   Project Profiles   Next Profile Go forward to

URL: http://geology.usgs.gov/postdoc/profiles/nilsen/index.html
Direct inquiries to Rama K. Kotra at rkotra@usgs.gov
Page Contact Information: Mendenhall Postdoctoral Fellowship Program Web Team
Last modified: 16:08:31 Thu 13 Dec 2012