The Lena River is one of the biggest Russian rivers draining into the Laptev Sea. Due to predicted increasing temperatures the permafrost areas surrounding the Lena will melt at increasing rates. With this melting high amounts of carbon, either organic or as methane will reach the waters of the Lena and the adjacent Laptev Sea. As methane is an important green house gas its further fate in the Lena Delta is of uttermost importance. Once methane is dissolved in the water column it can be either oxidized by methanotrophic bacteria and thus incorporated into the carbon cycle of the system or it is diluted with methane-poor sea water or it diffuses across the water-air interphase into the atmosphere. In the following we try to assess the fate of methane in the Lena River and the adjacent Buor Kaya Bay.