Study of Sediment Source and Fate Processes Using Isotopic Tracers in the Bluegrass

This study examines temporal and spatial variations in sediment organic matter at the watershed scale to better understand organic carbon and nitrogen cycling in-stream in a watershed exhibiting high in-stream storage. Temporally integrated weekly sediment samples were collected at multiple sites within a central Kentucky watershed over a nine-month sampling routine and analyzed for organic tracer distributions including stable carbon and nitrogen isotopes, total organic elemental carbon, total element nitrogen, and the carbon to nitrogen ratio. Results of this study showed distinct seasonal variations in the sediment organic tracers; spatial and hydrologic parameters were not as significant. All of the variations are attributed to microbial cycling of organic matter within temporary in-stream storage zones due to the single primary ex situ erosion source remaining consistent throughout the sampling routine.