Very worrying are the high methane readings close to Gakkel Ridge, the divergent fault line at the center of the Arctic Ocean, as earlier discussed in the post Methane Release caused by Earthquakes.
Furthermore very worrying are the high methane readings in between Greenland and Novaya Zemlya that coincide with high sea surface temperatures in that area. As discussed in the earlier post Is the North Pole no ice-free?, there are hot spots in the Arctic Ocean where sea surface temperatures are well over 10°C (50°F), which could be caused by undersea volcanic activity; this is the more dangerous as the area has seen methane bubbling up from destabilized hydrates.
For reference, images are added below of sea surface temperatures (top) and sea surface temperature anomalies (underneath) for September 19, 2013, showing sea surface temperatures recorded close to Svalbard that are far higher than even in the waters closer to the Atlantic Ocean.
Also for reference, highest mean and peak methane readings up to September 19, 2013, are added below.