 Anomalously high concentrations (up to 154 nM or 4400% supersaturation) of dissolved methane in the bottom layer of shelf water suggest that the bottom layer is somehow affected by near-bottom sources.Considering the possible formation mechanisms of such plumes, their studies indicated thermoabrasion and the effects of shallow gas or gas hydrates release.Research in 2008 in the Siberian Arctic has shown clathrate-derived methane being released through perforations in the seabed permafrost.