Brief Communication: The reliability of gas extraction techniques for analysing CH4 and N2O compositions in gas trapped in permafrost ice wedges

Methane (CH4) and nitrous oxide (N2O) compositions in ground ice may provide information on their production mechanisms in permafrost. However, existing gas extraction methods have not been well tested. We tested conventional wet and dry gas extraction methods using ice wedges from Alaska and Siberi...

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Bibliographic Details
Published in:The Cryosphere
Main Authors: Yang, Ji-Woong, Ahn, Jinho, Iwahana, Go, Han, Sangyoung, Kim, Kyungmin, Fedorov, Alexander
Format: Article in Journal/Newspaper
Language:English
Published: Copernicus Publications 2020
Subjects:
Ice
Online Access:https://doi.org/10.5194/tc-14-1311-2020
https://noa.gwlb.de/receive/cop_mods_00051339
https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00050995/tc-14-1311-2020.pdf
https://tc.copernicus.org/articles/14/1311/2020/tc-14-1311-2020.pdf
Description
Summary:Methane (CH4) and nitrous oxide (N2O) compositions in ground ice may provide information on their production mechanisms in permafrost. However, existing gas extraction methods have not been well tested. We tested conventional wet and dry gas extraction methods using ice wedges from Alaska and Siberia, finding that both methods can extract gas from the easily extractable parts of the ice (e.g. gas bubbles) and yield similar results for CH4 and N2O mixing ratios. We also found insignificant effects of microbial activity during wet extraction. However, both techniques were unable to fully extract gas from the ground ice, presumably because gas molecules adsorbed onto or enclosed in soil aggregates are not easily extractable. Estimation of gas production in a subfreezing environment of permafrost should consider such incomplete gas extraction.