Particulate Organic Carbon Patterns in a Mainstem Reservoir, Kentucky Lake, USA

Particulate carbon was measured spatially and temporally in the mainstem and embayments of Kentucky Lake U.S.A., the largest reservoir on the Tennessee River system. Samples were collected on pre-combusted glass fiber filters and particulate carbon and nitrogen determined with a CHN analyzer. An annual cycle was observed in the reservoir mainstem where peak particulate concentrations occurred primarily during the summer (with a yearly average 629 μg C·L−1). Concentrations of particulate carbon in embayments correlated with differential land-use practices on either side of the reservoir. Primarily agricultural western side embayments had elevated particulate carbon concentrations (1062 μg C·L−1). Forested eastern side embayments had average particulate carbon concentrations (736 μg C·L−1) that were more comparable to the mainstem. Contributions to summer POC in the reservoir mainstem were mainly from autochthonous sources, while contributions from upstream allochthonous sources were dominant during the winter.