Organic matter composition and greenhouse gas production of thawing subsea permafrost in the Laptev Sea.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 36030269.
- Also identified by DOI 10.1038/s41467-022-32696-0 and PMC identifier 9420143.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
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<sup>-2</sup> in subsea permafrost in the area, nine-fold exceeding organic carbon thaw rates for terrestrial permafrost. During 20-month incubations, CH<sub>4</sub> and CO<sub>2</sub> production averaged 1.7 nmol and 2.4 µmol g<sup>-1</sup> OC d<sup>-1</sup>, providing a baseline to assess the contribution of subsea permafrost to the high CH<sub>4</sub> fluxes and strong ocean acidification observed in the region.
Medical subject headings
- Greenhouse Gases
- Permafrost