Identifying nitrogen sources in the Choptank River

Stable isotopes of nitrogenIAN recently completed a project with the Midshore Riverkeeper Conservancy sourcing nitrogen inputs to the Choptank River watershed, including the Tuckahoe River watershed (a sub-watershed of the Choptank River). The Choptank River, on Maryland's eastern shore, has been shown to score poorly in terms of water quality and biotic integrity, with evidence that nutrient inputs (particularly nitrogen) are primarily responsible for it's degraded water quality. This study aimed to distinguish the distribution of these various sources of nitrogen using a combination of tissue nitrogen content (%N) and nitrogen stable isotope composition (δ15N) of aquatic plants and water samples. This approach can assist environmental managers to better understand sources of nitrogen in a watershed, and results from this study form a baseline for assessment of the effectiveness of best management practices targeting nutrient reductions in the Choptank River watershed.