Current rates and mechanisms of subsea permafrost degradation in the East Siberian Arctic Shelf

• Published in: Nature Communications
• Main Authors: Shakhova, Natalia, Semiletov, Igor, Gustafsson, Orjan, Sergienko, Valentin, Lobkovsky, Leopold, Dudarev, Oleg, Tumskoy, Vladimir, Grigoriev, Michael, Mazurov, Alexey, Salyuk, Anatoly, Ananiev, Roman, Koshurnikov, Andrey, Kosmach, Denis, Charkin, Alexander, Dmitrevsky, Nicolay, Karnaukh, Victor, Gunar, Alexey, Meluzov, Alexander, Chernykh, Denis
• Format: Text
• Language: English
• Published: Nature Publishing Group 2017
• Subjects: Article; Arctic; Ice; permafrost; Thermokarst
• Online Access: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5489687/; http://www.ncbi.nlm.nih.gov/pubmed/28639616; https://doi.org/10.1038/ncomms15872

The rates of subsea permafrost degradation and occurrence of gas-migration pathways are key factors controlling the East Siberian Arctic Shelf (ESAS) methane (CH4) 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 CH4 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−1 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 CH4 release in the Arctic.