The Impact of Global Warming on the Carbon Cycle of Arctic Permafrost: An Experimental and Field Based Study

• Main Authors: Onstott, Tullis C, Pffifner, Susan M, Chourey, Karuna
• Language: unknown
• Published: 2016
• Subjects: 54 ENVIRONMENTAL SCIENCES; Arctic; Axel Heiberg Island; Heiberg; Global warming; permafrost; Tundra
• Online Access: http://www.osti.gov/servlets/purl/1163483; https://www.osti.gov/biblio/1163483; https://doi.org/10.2172/1163483

Our results to date indicate that CO2 and CH4 fluxes from organic poor, Arctic cryosols on Axel Heiberg Island are net CH4 sinks and CO2 emitters in contrast to organic-rich peat deposits at sub-Arctic latitudes. This is based upon field observations and a 1.5 year long thawing experiment performed upon one meter long intact cores. The results of the core thawing experiments are in good agreement with field measurements. Metagenomic, metatranscriptomic and metaproteomic analyses indicate that high affinity aerobic methanotrophs belong to the uncultivated USCalpha are present in <1% abundance in these cryosols are are active in the field during the summer and in the core thawing experiments. The methanotrophs are 100 times more abundant than the methanogens. As a result mineral cryosols, which comprise 87% of Arctic tundra, are net methane sinks. Their presence and activity may account for the discrepancies observed between the atmospheric methane concentrations observed in the Arctic predicted by climate models and the observed seasonal fluctuations and decadal trends. This has not been done yet.