SS3.04 Biogeochemistry of DOC/DON in a Watershed Context
Date: Wednesday, June 12, 2002
Time: 2:15:00 PM
Location: Carson B
 
Schwede-ThomasSB, Ohio State University, Columbus, OH, USA, schwede.1@osu.edu
Chin , Y, , Ohio State University, Columbus, OH, USA, yo@geology.ohio-state.edu
 
CHANGES IN THE COMPOSITION OF DISSOLVED ORGANIC MATTER ALONG A HYDROLOGIC FLOWPATH IN THE WEEKS BAY WATERSHED, ALABAMA, USA
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Changes in land-use e.g., conversion of forested lands to agricultural or commercial use will influence the type, reactivity, and amount of dissolved organic matter (DOM) released to surface waters. Samples were taken for DOM analyses at several locations in the Weeks Bay watershed from the estuary to approximately 20 miles up the Fish River. A reverse phase (C-18) column method was used to extract the DOM from the surface waters, and the isolates were assayed by a number of spectroscopic methods. The properties of the DOM isolates changed dramatically from the upper reaches of the watershed to the estuary. Based upon UV-Visible, 13C-NMR, and fluorescence spectroscopy, much of the DOM in the forested freshwater sites originated from terrestrial sources, while DOM from the estuary appear to be produced in the water column by primary producers. Brackish water transition zones yielded DOM that appear to originate from both allochthonous and autochthonous sources, but maybe influenced by wastewater entering the river from the extensive residential development in the area.