The influence of oysters on sediment nitrogen cycling: an ecosystem approach

Cuny Baruch College, New York NY

Investigators

Abstract

Pollution of estuaries from human activities such as agriculture and urbanization has disrupted the global cycling of elements including carbon and nitrogen (N) and reduced stocks of coastal fisheries worldwide. Enhanced water quality in New York City has stimulated interest in reviving the previously abundant eastern oyster to the Hudson-Raritan estuary (HRE). Oysters filter the overlying water for food particles, and then deposit their waste to the sediments below. The delivery of N-rich waste to sediments may stimulate the microbial transformation of biologically active N into inert N gas. This process is the only pathway through which N is permanently removed from aquatic ecosystems; however, the environmental conditions under which oysters could enhance the activity of N-cycling microbes have not been previously examined. This study will document how two important factors, oyster density and water column N concentration, control the influence of oysters on sediment N cycling. The PI?s will quantify rates of oyster filtration, excretion, and sediment N transformations seasonally over a two-year period. This experiment will document the potential for the re-introduction of eastern oysters to enhance N removal in urbanized ecosystems. The results will directly inform the application of limited management funds towards oyster restoration projects, which can provide the maximum benefits for management of N pollution. To ensure the utility of the findings towards ongoing restoration activity, the PI?s will work in close cooperation with multiple stakeholders including government agencies and non-for-profit groups. Finally, this research supports the participation of students from high school through graduate school levels. The integration of public outreach, education, and robust experimental design are critical to the long-term conservation of urbanized aquatic environments.