HR: 0800h
AN: OS51B-0563    [Abstracts]
TI: Partitioning and Fate of Potentially Exported Soil Organic Carbon From the Eroding Coastline of Northern Alaska
AU: * Dou, F
EM: fdou@iarc.uaf.edu
AF: University of Alaska Fairbanks, International Arctic Research Center, Fairbanks, AK 99775 United States
AU: * Dou, F
EM: fdou@iarc.uaf.edu
AF: University of Alaska Fairbanks, Palmer Research Center, Palmer, AK 99645 United States
AU: Guo, L
EM: guol@iarc.uaf.edu
AF: University of Alaska Fairbanks, International Arctic Research Center, Fairbanks, AK 99775 United States
AU: Ping, C
EM: pfclp@uaa.alaska.edu
AF: University of Alaska Fairbanks, Palmer Research Center, Palmer, AK 99645 United States
AU: Jorgenson, T
EM: tjorgenson@abrinc.com
AF: ABR Inc., P.O. 80410, Fairbanks, AK 99708 United States
AB: Coastal erosion in Arctic regions has become a major transport pathway of organic carbon (OC) across the land/ocean interface under a warming climate and may significantly influence the carbon budget and biogeochemical cycle in the Arctic Ocean. The eroding coastline of northern Alaska not only loses millions of square meters of land underlain by permafrost, but also contributes to the magnitude of OC to be potentially mineralized. However, the flux, partitioning between dissolved and particulate phases, chemical characteristics, and fate of the eroded soil OC into the Arctic Ocean are poorly understood. The biogeochemical cycling of OC is controlled by its molecular composition and physicochemical parameters, such as temperature and moisture. It is critical to quantify the nature and magnitude of OC transformation under various environmental factors in order to better understand the carbon budget of the Arctic Ocean. A total of 300 soil organic matter samples have been collected along the northern Alaska coastline during summer 2005. The partitioning of soil OC (SOC) between dissolved and particulate phases was examined in the lab and the size fractioned SOC along with their bulk soils was characterized for its elemental (C and N) and isotopic (d13C and d15N) composition. Most of eroded SOC, over 95% of total OC, remained in the particulate form after dispersed into water. However, dissolved OC released during the erosion could be an active component in the decomposition and subsequent biogeochemial cycling of SOC. Specific decomposition rates of the size-fractionated SOC will be used to evaluate the fate of the eroded SOC.
DE: 0428 Carbon cycling (4806)
DE: 0475 Permafrost, cryosphere, and high-latitude processes (0702, 0716)
DE: 0486 Soils/pedology (1865)
DE: 1055 Organic and biogenic geochemistry
DE: 4870 Stable isotopes (0454, 1041)
SC: Ocean Sciences [OS]
MN: Fall Meeting 2005