Evolution of the Methane Cycle in the Siberian Arctic: Insights from Microbiological and Biogeochemical Studies
Final Report Abstract
In order to investigate the link between the methane dynamics in permafrost deposits and climate changes in the past, we studied the abundance, composition and methane production of methanogenic communities in Late Pleistocene and Holocene sediments of the Siberian Arctic. We detected intervals of increased methane concentrations in Late Pleistocene and Holocene deposits along a 42 ka old permafrost sequence from Kurungnakh Island in the Lena Delta (northeast Siberia). Increased amounts of archaeal life markers (intact phospholipid ethers) and a high variety in genetic fingerprints detected by 16S ribosomal ribonucleic acid (rRNA) gene analyses of methanogenic archaea suggest presently living and presumably active methanogenic archaea in distinct layers predominantly in Holocene deposits but also in deep frozen ground at 17 m depth. Potential methanogenic activity was confirmed by incubation experiments. By comparing methane concentrations, microbial incubation experiments, gene analysis of methanogens and microbial life markers (intact phospholipid esters and ethers) to already partly degraded membrane lipids such as archaeol and isoprenoid glycerol dialkyl glycerol tetraethers (GDGT), we demonstrated that archaeol likely represents a signal of past methanogenic archaea. The archaeol signal was used to reconstruct the response of methanogenic communities to past temperature changes in the Siberian Arctic and the data suggest higher methane emissions occurred during warm and wet periods, particularly during the Holocene and an interval in the Late Pleistocene. This new data on present and past methanogenic communities in the Siberian terrestrial permafrost imply that these microorganisms will respond to the predicted future temperature rise in the Arctic with increasing methane production as demonstrated in previous warmer periods.
Publications
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(2009). Response of the methane cycle to climate changes in the past and present. ICDP Kolloquium, March 16-18, 2009, Potsdam, Germany
Griess J., Mangelsdorf K. and Wagner D.
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(2010). Microbial driven methane dynamic in the Siberian Arctic during glacial-interglacial climate changes, IODP/ICDP Kolloquium 2010, Frankfurt/Main, Germany, March 9-11, 2010
Griess J., Mangelsdorf K. and Wagner D.
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(2010). Microbial driven methane dynamics in the Siberian Arctic during glacial-interglacial climate changes, Third European Conference on Permafrost, Longyearbyen, Svalbard, Norway, June 13-17, 2010
Griess J., Mangelsdorf K., Wagner D.
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(2010). Microbial driven methane dynamics in the Siberian Arctic during glacial-interglacial climate changes, VAAM Annual Meeting, Hannover, Germany, March 28-31, 2010
Griess J., Mangelsdorf K. and Wagner D.
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(2010). Response of the Siberian methane cycling microbial community to climate changes in Late Pleistocene and Holocene, 24th International Polar Meeting, Obergurgl, Austria, September 6-10, 2010
Griess J., Mangelsdorf K. and Wagner D.
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(2011). Biomarkers indicating the variability of methanogenic communities within Late Pleistocene and Holocene Permafrost deposits of Kurungnakh, Siberia, VAAM Annual Meeting, Tübingen, Germany, April 3-6, 2011
Griess J., Mangelsdorf K. and Wagner D.
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(2012). Response of methanogenic archaea to Late Pleistocene and Holocene climate changes in the Siberian Arctic. Global Biogeochemical Cycles
Bischoff J., Mangelsdorf K., Gattinger A., Schloter M., Kurchatova A.N., Herzschuh U. and Wagner D.
