Bubbles emanating from the East Siberian Shelf in the Arctic Ocean inject significant quantities of methane into the water column, reports a study published online this week in Nature Geoscience. The finding implies that large amounts of methane, generated by the degradation of submarine permafrost over thousands of years, are escaping the East Siberian Shelf.
Natalia Shakhova and colleagues used sonar-derived observations of bubble flux and measurements of seawater methane levels to monitor the emission of methane from the East Siberian Arctic Shelf to the overlying ocean. They found that bubbles escaping from the sea floor carried large amounts of methane into the overlying ocean. Furthermore, the concentrations of methane in the sea water fell significantly following the passage of two storms, suggesting that storms can help aid transport of methane to the atmosphere, where it acts as a potent greenhouse gas.