Hundreds of methane seeps discovered off US East Coast

BBC : At least 570 methane vents have been discovered off the US East Coast between North Carolina and Massachusetts, according to a study published in Nature Geoscience. Previous surveys had found only three. Adam Skarke of Mississippi State University and colleagues used multibeam sonar to map the water column over about 94 000 km² of seafloor. They say the source could be methane hydrate, an icy solid formed from frozen water and methane, buried under sediments on the ocean floor. Furthermore, the researchers say that although methane gas has been bubbling up through the water column for more than a thousand years, warming ocean temperatures may be accelerating the process. The methane, however, does not appear to be reaching the ocean surface or the atmosphere; instead, it may be oxidizing in the water and forming carbon dioxide. Undersea sediments may hold 10 times as much carbon as the atmosphere. Worldwide there may be as many as 30 000 of those methane seeps.