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DISSOLVED ORGANIC CARBON (DOC) CONCENTRATIONS IN SMALL STREAMS OF THE GEORGIA PIEDMONT
Citation:
Molinero, J. AND R A. Burke Jr. DISSOLVED ORGANIC CARBON (DOC) CONCENTRATIONS IN SMALL STREAMS OF THE GEORGIA PIEDMONT. Presented at North American Benthological Society Annual Meeting, Athens, GA, May 27-31, 2003.
Impact/Purpose:
Improve the scientific understanding of the processes controlling nutrient distributions in surface waters. Produce a suite of enhanced models for characterizing nutrient distributions in surface waters by incorporating improved process understanding in existing models (e.g., WASP), by developing new models (e.g., WHAM, reactive transport), and improving linkages between model components.
Description:
Dissolved organic matter (DOM) supports microbial activity and contributes to transport of N and P in streams. We have studied the impact of land uses on dissolved organic carbon (DOC) concentrations in 17 Georgia Piedmont headwater streams since January 2001. We classified the watersheds as developed (n =4), pasture/agricultural (n=4), forested (n=3) and mixed land uses (n=6). Mean DOC concentrations were low (0.95-1.28 mg C/l) in forest streams and somewhat higher in other watersheds. However, no significant correlations were found between stream DOC and watershed land use, and neither population density, road density nor discharge explained a significant portion of DOC variability. A significant inverse correlation was found between DOC and oxygen concentrations (R2 = 0.70). DON was a variable portion (5 to 46 %) of the total dissolved nitrogen in the streams. We conclude that (1) conversion of forest to other land uses increases DOC in Georgia Piedmont streams, that (2) DOM influences dissolved oxygen concentrations and (3) plays a significant role in the transport of nitrogen in these streams, but (4) land use and several common landscape indicators are poor predictors of DOC concentrations.