Subsea permafrost organic carbon stocks are large and of dominantly low reactivity.

Autor: Miesner F; Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Potsdam, Germany. frederieke.miesner@awi.de., Overduin PP; Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Potsdam, Germany., Grosse G; Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Potsdam, Germany.; Institute of Geosciences, University of Potsdam, Potsdam, Germany., Strauss J; Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Potsdam, Germany., Langer M; Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Potsdam, Germany.; Department of Earth Sciences, Faculty of Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands., Westermann S; Department of Geosciences, University of Oslo, Oslo, Norway.; Center for Biogeochemistry in the Anthropocene, University of Oslo, Oslo, Norway., Schneider von Deimling T; Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Potsdam, Germany., Brovkin V; Max Planck Institute for Meteorology, Hamburg, Germany.; CEN, University of Hamburg, Hamburg, Germany., Arndt S; BGeoSys, Department of Geosciences, Environment and Society, Université libre de Bruxelles, Brussels, Belgium.
Jazyk: angličtina
Zdroj: Scientific reports [Sci Rep] 2023 Jun 09; Vol. 13 (1), pp. 9425. Date of Electronic Publication: 2023 Jun 09.
DOI: 10.1038/s41598-023-36471-z
Abstrakt: Subsea permafrost carbon pools below the Arctic shelf seas are a major unknown in the global carbon cycle. We combine a numerical model of sedimentation and permafrost evolution with simplified carbon turnover to estimate accumulation and microbial decomposition of organic matter on the pan-Arctic shelf over the past four glacial cycles. We find that Arctic shelf permafrost is a globally important long-term carbon sink storing 2822 (1518-4982) Pg OC, double the amount stored in lowland permafrost. Although currently thawing, prior microbial decomposition and organic matter aging limit decomposition rates to less than 48 Tg OC/yr (25-85) constraining emissions due to thaw and suggesting that the large permafrost shelf carbon pool is largely insensitive to thaw. We identify an urgent need to reduce uncertainty in rates of microbial decomposition of organic matter in cold and saline subaquatic environments. Large emissions of methane more likely derive from older and deeper sources than from organic matter in thawing permafrost.
(© 2023. The Author(s).)
Databáze: MEDLINE
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