Results of methane concentration measurement in the atmosphere over the western seas of the Russian Arctic and their comparison with underwater video data

Résumé fourni par la source

The article presents the values of methane concentration in the near-surface layer of atmospheric air directly measured from the board of “Akademik Mstislav Keldysh” research vessel in the Kara and Barents Seas in the summer of 2024. It is the first time when the marine expeditionary data for the Russian part of the Arctic have been compared with the data obtained by “Videomodule” towed unmanned underwater vehicle engineered at the Shirshov Institute of Oceanology of the Russian Academy of Sciences. The analysis shows that bacterial mats in areas of methane seepage in the Arctic have a limited contribution to the increase in CH 4 concentration in the near-surface layer of the atmosphere. Their influence is likely to be noticeable only in shallow areas (up to 50 m deep), where methane can reach the water surface without being fully oxidized in the ocean. At the same time, short-lived peaks (lasting up to several minutes) of elevated CH₄ concentrations are observed, reaching 3 ppm or higher. The main factor influencing the variability of atmospheric CH 4 concentrations is the direction of air mass transport: when air masses are advected from the north and west, minimum CH 4 concentrations (1.98 ppm) are recorded; conversely, when air masses are carried away from the mainland, methane concentrations increase (up to 2.10 ppm when from the Yamal Peninsula).

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