AI Article Synopsis
- * New research indicates that the ice-bonded permafrost in the ESAS has been moving downward by approximately 14 cm each year over the last 31-32 years, contradicting earlier beliefs about long-term stability post-inundation.
- * The presence of thermokarst patterns and gas migration suggests ongoing changes in the subsea environment, highlighting the need to understand permafrost degradation to predict future methane release accurately.
Article Abstract
The rates of subsea permafrost degradation and occurrence of gas-migration pathways are key factors controlling the East Siberian Arctic Shelf (ESAS) methane (CH) emissions, yet these factors still require assessment. It is thought that after inundation, permafrost-degradation rates would decrease over time and submerged thaw-lake taliks would freeze; therefore, no CH release would occur for millennia. Here we present results of the first comprehensive scientific re-drilling to show that subsea permafrost in the near-shore zone of the ESAS has a downward movement of the ice-bonded permafrost table of ∼14 cm year over the past 31-32 years. Our data reveal polygonal thermokarst patterns on the seafloor and gas-migration associated with submerged taliks, ice scouring and pockmarks. Knowing the rate and mechanisms of subsea permafrost degradation is a prerequisite to meaningful predictions of near-future CH release in the Arctic.
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|---|---|
| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5489687 | PMC |
| http://dx.doi.org/10.1038/ncomms15872 | DOI Listing |
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