Origin of CO$_2$, CH$_4$, and N$_2$O trapped in ice wedges in central Yakutia and their relationship

• Published in: Permafrost and Periglacial Processes
• Main Authors: Yang, Ji-Woong, Ahn, Jinho, Iwahana, Go, Ko, Nayeon, Kim, Jihoon, Kim, Kyungmin, Fedorov, Alexander, Han, Sangyoung
• Other Authors: Laboratoire des Sciences du Climat et de l'Environnement Gif-sur-Yvette (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Seoul National University Seoul (SNU), International Arctic Research Center (IARC), University of Alaska Fairbanks (UAF), Korea Institute of Geoscience and Mineral Resources, Melnikov Permafrost Institute, Siberian Branch of the Russian Academy of Sciences (SB RAS), Ministry of Oceans and Fisheries, MOF: 1525011795; National Research Foundation of Korea, NRF: 2018R1A5A1024958, 2020M1A5A1110607, This study is supported by National Research Foundation of Korea (2020M1A5A1110607; 2018R1A5A1024958) and Korea Ministry of Oceans and Fisheries (1525011795).
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2023
• Subjects: carbon dioxide; central Yakutia; ice wedges; methane; nitrous oxide; permafrost; [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces; environment; Churapcha; Syrdakh; Ice; Permafrost and Periglacial Processes; wedge*; Yakutia; Siberia
• Online Access: https://hal.science/hal-04122369; https://hal.science/hal-04122369/document; https://hal.science/hal-04122369/file/Permafrost%20%20%20Periglacial%20-%202022%20-%20Yang%20-%20Origin%20of%20CO2%20%20CH4%20%20and%20N2O%20trapped%20in%20ice%20wedges%20in%20central%20Yakutia%20and%20their.pdf; https://doi.org/10.1002/ppp.2176

International audience Permafrost thawing as a result of global warming is expected to foster the biological remineralization of intact organic carbon and nitrogen and release greenhouse gas (GHG) into the atmosphere, which will have positive feedback for future global warming. However, GHG budgets and their controls in permafrost ground ice are not yet fully understood. This study aims to better understand the control mechanisms of GHG in ground ice by using new gas and chemistry data. In this study, we present new data on carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) mixing ratios in three different ice wedges, Churapcha, Syrdakh, and Cyuie, located in central Yakutia, Siberia. The GHG mixing ratios in the studied ice wedges range from 0.0% to 13.8% CO2, 1.3–91.2 ppm CH4, and 0% and 0–1414 N2O. In particular, all three ice wedges demonstrate that ice-wedge samples enriched in CH4 were depleted in N2O mixing ratios and vice versa. N2–O2–Ar compositions indicate that the studied ice wedges were most likely formed by dry snow or hoarfrost, not by freezing of snow meltwater, and the O2-consuming biological metabolism was active. Most of the observed GHG mixing ratios cannot be explained without microbial metabolism. The inhibitory impact of denitrification products of nitrate (including N2O) could be an important control of the ice-wedge CH4 mixing ratio.