AI Article Synopsis
- Subsea permafrost is a significant carbon storage area that could potentially release greenhouse gases as it thaws, but there is limited observational data leading to uncertainties about its impact.
- Five cores from the Laptev Sea were analyzed to assess organic carbon storage, degradation, and greenhouse gas production, revealing a history of sediment deposition over 160,000 years from both forest and tundra sources.
- The study estimates a thaw rate of 1.3 kg of organic carbon per square meter annually in subsea permafrost, which is much higher than terrestrial permafrost, and measured methane and carbon dioxide production during incubation, providing insight into subsea permafrost's role in ocean carbon dynamics.
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 in subsea permafrost in the area, nine-fold exceeding organic carbon thaw rates for terrestrial permafrost. During 20-month incubations, CH and CO production averaged 1.7 nmol and 2.4 µmol g OC d, providing a baseline to assess the contribution of subsea permafrost to the high CH fluxes and strong ocean acidification observed in the region.
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Source |
|---|---|
| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC9420143 | PMC |
| http://dx.doi.org/10.1038/s41467-022-32696-0 | DOI Listing |
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