Estuaries, which link rivers and oceans, provide a host of ecological services including habitat protection and water filtration and support many marine organisms such as oysters, clams, crabs, and fish. Unfortunately, increased inputs of nutrients and other pollutants have degraded the water quality in these areas. In estuaries, excess nitrogen inputs are a major source of pollution, resulting in harmful algae blooms, habitat loss, reduced oxygen in the water, fish kills and dead zones. Oyster aquaculture can potentially be used to improve water quality and lessen the effects of nitrogen pollution while supporting the seafood industry. Oysters remove nitrogen from the water through growth as they incorporate nitrogen into their shells and tissue, and they enhance denitrification, a natural microbial mechanism that transforms nitrogen into an inert gas that algae and other organisms are unable to use. Since oysters can improve water quality by removing nitrogen, there is growing interest in incorporating oyster aquaculture into nutrient trading programs designed to meet nutrient reduction goals. However, we currently lack the data necessary to include denitrification from oyster aquaculture in such management plans. My research aims to fill this gap by determining the fate of nitrogen at sites using various culture methods in order to evaluate oyster aquaculture as a best management practice to protect against nitrogen over-enrichment. Working with Virginia Sea Grant and the Virginia Institute of Marine Science, this project will directly assess the effects of oyster aquaculture on denitrification rates and examine the suitability of including oyster aquaculture in nutrient trading programs, a market-based approach used to meet nutrient reduction goals and improve water quality. As human populations continue to grow, nitrogen loading will increase in coastal ecosystems and our efforts to better understand the interactions between aquaculture and the nitrogen cycle will become even more critical in maintaining and enhancing coastal ecosystems for future generations.