Measured methane concentrations in the ice cover of ponds and lakes on Samoylov Island (Lena-River-Delta in northern Siberia). Methane concentration were extracted from ice core samples. The location of each sample relative to the lake surface is indicated by a minimum and maximum depth. The ice cores were extracted by cutting ice columns to a depth of about 70 cm from the ice cover. The ice samples were melted in 1 L plastic containers. Methan concentration were obtained by head-space analysis. For a detailed description of the methods see Langer et al. (2015).