EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Potential greenhouse gas production by organic matter decomposition in thawing subsea permafrost

Birgit Wild1,2, Natalia Shakhova3, Oleg Dudarev3,4, Alexey Ruban3, Denis Kosmach4, Vladimir Tumskoy5,6, Tommaso Tesi7, Hanna Joß1, Inna Nybom1, Helena Alexanderson8, Martin Jakobsson2,9, Alexey Mazurov3, Igor Semiletov4,10, and Örjan Gustafsson1,2
Birgit Wild et al.
  • 1Department of Environmental Science, Stockholm University, Stockholm, Sweden (
  • 2Bolin Centre for Climate Research, Stockholm University, Stockholm, Sweden
  • 3Tomsk Polytechnic University, Tomsk, Russia
  • 4Pacific Oceanological Institute, Far Eastern Branch of Russian Academy of Sciences, Vladivostok, Russia
  • 5Moscow State University, Moscow, Russia
  • 6Melnikov Permafrost Institute, Siberian Branch of Russian Academy of Sciences, Yakutsk, Russia
  • 7Institute of Polar Sciences, National Research Council, Bologna, Italy
  • 8Department of Geology, Lund University, Lund, Sweden
  • 9Department of Geological Sciences, Stockholm University, Stockholm, Sweden
  • 10Institute of Ecology, Higher School of Economics, Moscow, Russia

Subsea permafrost extends over vast areas across the East Siberian Arctic Ocean shelves and might harbor a large and vulnerable organic matter pool. Field campaigns have observed strongly elevated concentrations of CH4 in seawater above subsea permafrost that might stem from microbial degradation of thawing subsea permafrost organic matter, from release of CH4 stored within subsea permafrost, from shallow CH4 hydrates or from deeper thermogenic/petrogenic CH4 pools. We here assess the potential production of CH4, as well as CO2 and N2O by organic matter degradation in subsea permafrost after thaw. To that end, we employ a set of subsea permafrost drill cores from the Buor-Khaya Bay in the south-eastern Laptev Sea where previous studies have observed a rapid deepening of the ice-bonded permafrost table. Preliminary data from an ongoing laboratory incubation experiment suggest the production of both CH4 and CO2 by decomposition of thawed subsea permafrost organic matter, while N2O production was negligible. These data will be combined with detailed biomarker analysis to constrain the vulnerability of subsea permafrost organic matter to degradation to greenhouse gases upon thaw.

How to cite: Wild, B., Shakhova, N., Dudarev, O., Ruban, A., Kosmach, D., Tumskoy, V., Tesi, T., Joß, H., Nybom, I., Alexanderson, H., Jakobsson, M., Mazurov, A., Semiletov, I., and Gustafsson, Ö.: Potential greenhouse gas production by organic matter decomposition in thawing subsea permafrost, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-5766,, 2021.