Methane and Dissolved Organic Matter in the Ground Ice Samples from Central Yamal: Implications to Biogeochemical Cycling and Greenhouse Gas Emission

Permafrost thawing leads to mobilization of the vast carbon pool into modern biogeochemical cycling through the enhanced release of dissolved organic matter (DOM) and production of greenhouse gases (CO 2 and CH 4 ). In this work, we focus on the study of methane and DOM distribution and genesis in t...

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Bibliographic Details
Published in:Geosciences
Main Authors: Petr B. Semenov, Anfisa A. Pismeniuk, Sergei A. Malyshev, Marina O. Leibman, Irina D. Streletskaya, Elizaveta V. Shatrova, Alexander I. Kizyakov, Boris G. Vanshtein
Format: Article in Journal/Newspaper
Language:English
Published: MDPI AG 2020
Subjects:
permafrost
biogeochemical cycling
climate change
greenhouse gas emission
dissolved organic matter
ground ice
Geology
QE1-996.5
Arctic
Climate change
Ice
wedge*
Online Access:https://doi.org/10.3390/geosciences10110450
https://doaj.org/article/1ced6b32b8c0439ebc20f5b47d1cbce3
Description
Summary:Permafrost thawing leads to mobilization of the vast carbon pool into modern biogeochemical cycling through the enhanced release of dissolved organic matter (DOM) and production of greenhouse gases (CO 2 and CH 4 ). In this work, we focus on the study of methane and DOM distribution and genesis in the ground ice samples of thermodenudational exposure in the Central Yamal (Russian Arctic). We propose that the liberation of the ice-trapped CH 4 and generation of CO 2 by DOM mineralization are the earliest factors of atmospheric greenhouse gases emission as a result of permafrost thawing. The observed enormously “light ” isotope signatures of methane (δ 13 C < −80‰, δD < −390‰) found in the tabular ground ice units significantly divergent in morphology and localization within the exposuremay be related to subzero (cryogenic) carbonate reduction a as significant factor of the local methane enrichment. DOM is mainly formed (>88%) by biochemically refractory humic acids. Distribution of the labile protein-like DOM reflects the specific features of carbon and nitrogen cycles in the tabular ground ice and ice wedge samples. Tabular ground ice units are shown to be a significant source of methane and high quality organic matter as well as dissolved inorganic nitrogen (DIN). Ice wedges express a high variation in DOM composition and lability.

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