Lakes in the area of Bovanenkovo and Kruzenshternskoye areas (pink outlines) in the Landsat-8 image (a - visible colors, b - infrared synthesis). Picture: Vasily Bogoyavlensky A feature of these thermokarst lakes are craters or funnels in the sediment on the floor through which they are haemorrhaging methane. These pockmarks are similar to those found on the floors of the great oceans. Scientists say these leaks are year round in lakes where carbon processing and methane emission occur even at temperatures close to zero degrees Celcius. Detailed study of satellite data from 2015-16 has identified more than 200 lakes which are seen as an active source of methane emissions. The gas is of both a biochemical nature, the result of microbial activity released by permafrost thawing, and catagenesis, formed in deep ground layers.



Lake with craters of gas emissions in the north of the Yamal Peninsula, pictured by Vasily Bogoyavlensky in 2015. Satellite image of thermokarst lake with craters of gas emissions to the north of Sabetta, taken on June 24, 2011 from the WorldView-2 satellite. Professor Vasily Bogoyavlensky, deputy director of the Moscow-based Oil and Gas Research Institute, part of the Russian Academy of Sciences, said: 'These lakes have a number of features, which can help identify them from a distance: the anomalous blue colour of water, the presence of craters on the bottom and gas seeps in the water, the traces of gas in the seasonal ice cover, as well as active coastal erosion and permafrost swelling near the water's edge.' The sulphur in the gas leaks results in algae flourishing in these Arctic waters, which give the lakes their distinctive hue. He warned that 'many of the sites with gas emissions are located close to the territory of oil and gas deposits'. The surface of Lake Hekhekhanto with traces of gas sipes in ice according to WorldView-2, May 29, 2011. Satellite image of partially dried lake with craters of gas emissions in the north of the Yamal Peninsula. Pictures: Vasily Bogoyavlensky Moreover, he sees an 'interrelation of gas emissions and seismic activity. 'For example, over one of the gas deposits (in Yamal), lakes are located along two lines ... looking like a giant cross'. This suggests a 'genetic connection of craters with deep faults in the earth's crust, but to confirm we need to conduct thorough seismic research'. His work in highlighting the lakes with bubbling methane follow revelations this week of several thousand pingos, some of which are filled with gas which could 'explode' forming giant craters - as seen in pictures here. At least 10 craters are known about caused by such eruptions.