HR: 1340h
AN: B53A-0920    [Abstracts]
TI: Reducing uncertainty in emission estimates of methane bubbling from arctic lakes
AU: * Walter, K M
EM: ftkmw1@uaf.edu
AF: University of Alaska, Fairbanks, Water and Environmental Research Center, Fairbanks, AK 99775,
AU: Vas, D
EM: fsdav2@uaf.edu
AF: University of Alaska, Fairbanks, Water and Environmental Research Center, Fairbanks, AK 99775,
AU: Brosius, L
EM: lsb2@uaf.edu
AF: University of Alaska, Fairbanks, Water and Environmental Research Center, Fairbanks, AK 99775,
AU: Sarkar, S
EM: ftss4@uaf.edu
AF: University of Alaska, Fairbanks, Geophysical Institute, Fairbanks, AK 99775,
AU: Grosse, G
EM: ggrosse@gi.alaska.edu
AF: University of Alaska, Fairbanks, Geophysical Institute, Fairbanks, AK 99775,
AB: A recent first-order estimate suggests that arctic lakes are significant emitters of methane (24 ± 10 Tg CH4 yr-1) contributing as much as ~6% of global atmospheric CH4 sources annually. Emissions from arctic lakes are projected to increase as permafrost thaws in the Arctic, releasing tens of thousands of teragrams to the atmosphere in the form of bubbles. Emissions are thought to be particularly high from lakes influenced by permafrost degradation, a process that discharges labile organic matter to anaerobic lake bottoms, fueling biological methane production and emissions. Complete thaw of permafrost beneath lakes may destabilize deeper methane sources such as hydrate methane and natural gas, providing pathways for the release of sub- permafrost and/or intra-permafrost methane from biogenic or thermogenic sources. Alternatively, emission of deep methane to the atmosphere may occur independently from permafrost warming dynamics, for instance through geological fault activity. Despite the potential for large release of deep methane pools to the atmosphere, little is known about the occurrence, extent, and vulnerability of these methane sources. Here we present results of our efforts as part of the IPY to quantify, map, and project biological and geological methane emissions from arctic lakes in Alaska and Siberia in conjunction with permafrost degradation. This effort includes pioneering new methods of measuring methane bubbling (dominant mode of emissions) from lakes using field studies, geophysical measurements, isotope geochemistry, remote sensing Synthetic Aperture Radar analysis and the establishment of a Pan-Arctic Lake-Ice Methane Monitoring Network (PALIMMN).
DE: 0426 Biosphere/atmosphere interactions (0315)
DE: 0428 Carbon cycling (4806)
DE: 0490 Trace gases
DE: 1615 Biogeochemical cycles, processes, and modeling (0412, 0414, 0793, 4805, 4912)
DE: 1631 Land/atmosphere interactions (1218, 1843, 3322)
SC: Biogeosciences [B]
MN: 2007 Fall Meeting