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

ABSTRACT: 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, i

SUBMITTER: Shakhova N 

PROVIDER: S-EPMC5489687 | biostudies-literature | 2017 Jun

REPOSITORIES: biostudies-literature