Geochemistry of sediments from Arctic thermokarst lakes and lagoons on the Bykovsky Peninsula, Siberia

In coastal Arctic permafrost regions, thermokarst lagoons represent the transition state from a freshwater lacustrine to a marine environment, and receive little attention regarding their role for greenhouse gas production and release. The geochemical features of a thermokarst lagoon were compared with two thermokarst lakes on the Bykovsky Peninsula in northeastern Siberia. This data set includes pH, major cations and anions, alkalinity, salinity, and dissolved iron (ferric and ferrous) concentrations from porewater of lake and lagoon sediments; the concentration and stable isotopic signature of CH4 in small plug samples from the sediment cores; total carbon (TC), total organic carbon (TOC), total nitrogen (TN), and total sulfur (TS) measured from the bulk sediment; and several biomarker indices (e.g. CPI, Paq) were calculated based on n-alkane concentrations to characterize the origin of organic matter (OM) in the lakes.