Clesceri, E. J.. University of North Carolina, erika.clesceri@sph.unc.edu
Martens, C. J.. University of North Carolina, cmartens@marine.unc.edu
Alperin, M. J.. University of North Carolina, alperin@marine.unc.edu
Albert, D. B.. University of North Carolina, albert@marine.unc.edu

 
STABLE ISOTOPIC TRACING OF PARTICULATE ORGANIC MATTER IN SESTON AND SEDIMENTS FROM AN EUTROPHIC ESTUARY IN NORTH CAROLINA, USA
 
Eutrophication caused by anthropogenic inputs of nitrogen is a significant mechanism altering coastal ecosystems worldwide. The weakly-flushed Neuse River Estuary, North Carolina continues to exhibit several symptoms indicative of nitrogen-driven eutrophication including excessive nuisance algal blooms, toxic blooms, anoxia, and fish kills. Concentrations and stable isotopic ratios of organic carbon and nitrogen were measured in surface and bottom water seston and surficial sediments along the estuarine salinity gradient to evaluate organic matter sources and biogeochemical coupling between seston and sediments. Surficial sediment surveys reveal a negative correlation between the two isotope distributions. Heaviest N isotope values, classically considered "marine", were found in upstream oligohaline regions along the estuarine gradient. These enriched nitrogen isotope values may be related to sediment denitrification processes or upstream inputs of isotopically enriched agricultural runoff or sewage. In this agriculturally impacted estuary, terrestrial organic matter can not be traced by depleted nitrogen isotopic values. Comparison of the C and N isotopic composition of sestonic organic matter with the surficial sediment will further clarify the transport and processing between these pools. Identification of sources and ecosystem processing of excess N loading should benefit coastal watershed nutrient management plans.
 
Day: Tuesday, Feb. 2
Time: 09:45 - 10:00am
Location: Eldorado Hotel
 
Code: SS32TU0945E