HR: 14:25h
AN: B43F-04    [Abstracts]
TI: Organic Matter Export from North Slope Rivers of Alaska: Variations in Stable C and N Isotope Ratios over the Annual Hydrograph and Implications for Tracking Land-Derived Organic Matter in Coastal Waters
AU: * McClelland, J W
EM: jimm@mail.utexas.edu
AF: University of Texas at Austin, Marine Science Institute, Port Aransas, TX 78373, United States
AU: Townsend-Small, A
EM: atownsen@uci.edu
AF: University of California at Irvine, Department of Earth System Science, Irvine, CA 92697, United States
AU: Holmes, R M
EM: rmholmes@whrc.org
AF: The Woods Hole Research Center, 149 Woods Hole Road, Falmouth, MA 02540, United States
AU: Stieglitz, M
EM: marc.stieglitz@ce.gatech.edu
AF: Georgia Institute of Technology, School of Civil and Environmental Engineering, Atlanta, GA 30332, United States
AU: Pan, F
EM: feifei.pan@ce.gatech.edu
AF: Georgia Institute of Technology, School of Civil and Environmental Engineering, Atlanta, GA 30332, United States
AU: Peterson, B J
EM: peterson@mbl.edu
AF: Marine Biological Laboratory, The Ecosystems Center, Woods Hole, MA 02543, United States
AB: Wide variations in dissolved and particulate organic matter concentrations have been identified in arctic rivers over the annual hydrograph, leading to revised estimates of organic matter export to coastal waters. The fate of this organic matter is of fundamental interest to researchers studying biogeochemical cycling in the Arctic, and also of broader interest as a component of the global carbon budget. Normalized carbon export (i.e. by watershed area) from arctic rivers is disproportionately large compared to rivers globally, and carbon export from arctic rivers may be particularly susceptible to change under warmer conditions. This presentation will focus on stable C and N isotope ratios of organic matter exported from the Kuparuk, Sagavanirktok, and Colville rivers during 2006 and 2007. Major increases in the stable isotope ratios of dissolved organic carbon (DOC) and particulate organic nitrogen (PON) were observed between ice break-up and late summer. At the same time, a major decrease in the stable isotope ratios of particulate organic carbon (POC) was observed. Monthly and annual discharge-weighted averages of the isotope values will be presented and the relevance of these values as end-members for organic matter tracking in coastal waters will be discussed.
DE: 0428 Carbon cycling (4806)
DE: 0442 Estuarine and nearshore processes (4235)
DE: 0469 Nitrogen cycling
DE: 0744 Rivers (0483, 1856)
DE: 4217 Coastal processes
SC: Biogeosciences [B]
MN: 2007 Fall Meeting