HYDROGEOMORPHIC AND LANDSCAPE INFLUENCES ON DISSOLVED ORGANIC MATTER IN STREAMS AND RIVERS ON THE SOUTH CAROLINA COASTAL PLAIN

Dissolved organic matter (DOM) is recognized as a major component in the global carbon cycle and is an important driver of numerous biogeochemical processes in aquatic ecosystems, both in-stream and downstream in estuaries. This study sought to characterize chromophoric DOM (CDOM) in major rivers and their tributaries of South Carolina Coastal Plain to assess the impact of land use and other factors on water quality. During eight trips from June 11 to July 9 of 2014 throughout the South Carolina Coastal Plain, we visited 54 sites, where we measured field parameters (temperature, dissolved oxygen, pH, and specific conductance) and collected water samples for laboratory analysis. All sampling was done during baseflow conditions. The water samples were filtered and analyzed for dissolved organic carbon (DOC) and dissolved nutrients. Sample sites included headwater wetlands and springs, streams and rivers, and water table monitoring wells. We measured stream discharge at stream sites where there was not a US Geological Survey (USGS) gaging station. We used the discharge measurements to make point estimates of fluxes of the nutrients and DOC during baseflow. Spectral analysis of the filtered water samples was done from 200-800 nm using a Shimadzu UV-1700 spectrophotometer. We calculated absorption coefficients, spectral slope coefficients, and related metrics to facilitate broad characterizations of the nature of the CDOM in the water based on source and other landscape factors. This poster will summarize the results of those analyses.