HR: 0800h
AN: C41A-0192    [Abstracts]
TI: Amplified carbon release from vast West Siberian peatlands by 2100
AU: * Frey, K E
EM: frey@ucla.edu
AF: University of California, Los Angeles, Dept. of Geography, Los Angeles, CA 90095 United States
AU: Smith, L C
EM: lsmith@geog.ucla.edu
AF: University of California, Los Angeles, Dept. of Geography, Los Angeles, CA 90095 United States
AU: Smith, L C
EM: lsmith@geog.ucla.edu
AF: University of California, Los Angeles, Dept. of Earth and Space Sciences, Los Angeles, CA 90095 United States
AB: The potential impacts of climate change on peatland carbon cycling are subject to ongoing debate. Since the Last Glacial Maximum, northern peatlands have behaved primarily as a net sink of atmospheric carbon, storing up to $\sim$455 Pg C or one-third of the global soil carbon pool. However, the likely fate of this carbon under a warming climate remains a major unanswered question in Arctic Science and is particularly relevant in West Siberia, which contains the world's largest stores of peat carbon, exports massive volumes of freshwater and dissolved organic carbon (DOC) to the Arctic Ocean, and is warming faster than the Arctic as a whole. Here we present extensive DOC measurements from 96 watersheds distributed throughout West Siberia, providing data on a much larger spatial scale than previous studies and for the first time explicitly examining stream DOC in permafrost environments. Our results show cold, permafrost-influenced watersheds release little DOC to streams. However, we find drastically higher values in warm, permafrost-free watersheds, rising as a function of peatland abundance. The two regimes are demarcated by the position of the -$2\deg$C air temperature isotherm, which is also approximately coincident with the permafrost boundary. Climate models predict near-doubling of these warm areas in West Siberia by 2100, suggesting up to 700$%$ increases in stream DOC concentrations and 2.7-4.3 Tg yr$^{-1}$ increases in DOC flux from the region.
DE: 1823 Frozen ground
DE: 1860 Runoff and streamflow
DE: 1871 Surface water quality
DE: 1890 Wetlands
DE: 1615 Biogeochemical processes (4805)
SC: Cryosphere [C]
MN: 2004 AGU Fall Meeting