Organic matter composition and greenhouse gas production of thawing subsea permafrost in the Laptev Sea
Year: 2022
Type: article
Abstract: Subsea permafrost represents a large carbon pool that might be or become a significant greenhouse gas source. Scarcity of observational data causes large uncertainties. We here use five 21-56 m long subsea permafrost cores from the Laptev Sea to constrain organic carbon (OC) storage and sources, degradation state and potential greenhouse gas production upon thaw. Grain sizes, optically-stimulated luminescence and biomarkers suggest deposition of aeolian silt and fluvial sand over 160 000 years, with dominant fluvial/alluvial deposition of forest- and tundra-derived organic matter. We estimate an annual thaw rate of 1.3 ± 0.6 kg OC m−2 in subsea permafrost in the area, nine-fold exceeding organic carbon thaw rates for terrestrial permafrost. During 20-month incubations, CH4 and CO2 production averaged 1.7 nmol and 2.4 µmol g−1 OC d−1, providing a baseline to assess the contribution of subsea permafrost to the high CH4 fluxes and strong ocean acidification observed in the region.
Source: Nature Communications
Institutions: Stockholm University, Bolin Centre for Climate Research, Russian Academy of Sciences, National Research Tomsk State University, V.I. Il'ichev Pacific Oceanological Institute, Far Eastern Branch of the Russian Academy of Sciences, Tomsk Polytechnic University, Melnikov Permafrost Institute of the Siberian Branch of the Russian Academy of Science, Siberian Branch of the Russian Academy of Sciences, National Research Council, University of Tübingen, Lund University, National Research University Higher School of Economics
Language: English
Subfield: Atmospheric Science
Field: Earth and Planetary Sciences
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $5,890
Awards: G1447768702, G1505834979, G1588501953, G200408876, G2833203879, Grand Challenges in Climate Research: Thawing Permafrost in the Arctic AND Brown Cloud Emissions from India and China, Nitrous oxide fluxes from the East Siberian Arctic Shelf, Cryosphere-Carbon on Top of the Earth (CC-Top): Decreasing Uncertainties of Thawing Permafrost and Collapsing Methane Hydrates in the Arctic, G4742269901, Emissions of the strong greenhouse gas nitrous oxide from thawing coastal and subsea permafrost in the Siberian Arctic, G6961348902, G712881263, G826183916
OpenAlex ID: W4293325317