PHOSPHORUS AS A BIOGEOCHEMICAL INDICATOR OF ANTHROPOGENIC EFFECTS IN ESTUARINE WATERSHEDS

Nutrient pollution represents a significant concern within estuarine watersheds, resulting in a wide array of negative consequences, including eutrophic effects. Increased introduction of phosphorus constitutes a critical component of this environmental issue. Various land use practices serve as contributors of phosphorus, and determination of pollutant sources remains an obstacle. This project examines phosphorus and total suspended solid concentrations within the interior waters of two tidal creeks, along with identification of various phosphorus compounds found within wetland sediments in an attempt to link these findings with corresponding anthropogenic sources. Use of P-31 nuclear magnetic resonance (NMR) allows direct measurement of all chemical forms of P within the sediments, providing a true picture of organic P content, which is not commonly focused on in water quality assessments. Total P, orthophosphate, and organic P will also be analyzed within the water samples, using persulfate digestion and colorimetric analysis. TSS measurements will provide additional data beneficial for correlations between sediment input and P transport. The sampling environment includes two contrasting watersheds within southeastern North Carolina, Hewletts and Pages Creeks, illustrating varying land uses, salinity levels, and soil attributes. Preliminary results suggest the presence of alternative P compounds throughout these tidal creek environments. TSS concentrations are highest in the most developed, upper reaches of Hewletts Creek, while Pages Creek illustrates elevated levels within the more tidally influenced portion. Further analysis will determine specific land use impacts. The results of this project will provide valuable information regarding phosphorus behavior and inputs to be used to create an environmental analysis tool for the assessment of watershed health.