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.
The dataset was compiled into an excel file with samples in rows and environmental parameters in columns.
Samples were taken from Bykovsky Peninsula, southeast of the Lena Delta in the Buor-Khaya Gulf of the Laptev Sea in northeastern Siberia, Russia, during the field expedition in April 2017. Three cores (PG2420, PG2426, and PG2423) were retrieved from Lake Golzovoye (LG), Polar Fox Lagoon (PFL) and Lake Northern Polar Fox (LNPF), with drilling depths from the sediment surface of 5.2, 5.4, and 6.1 m, respectively.
Porewater samples were extracted using a hydraulic press in an anoxic glovebox and then filtered to 0.45 µm microporous membrane. pH was measured with a WTW MultiLab 540 probe (WTW, Germany). Samples were analyzed by suppressed ion chromatography for all major cations and anions. Alkalinity was measured by colorimetric titration. Dissolved iron (ferric and ferrous) concentrations in pore water were measured via spectrophotometry by the ferrozine method (Viollier et al. 2000), with a detection limit of 0.25 μM. Samples were measured at GFZ German Research Centre for Geosciences.
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10.5880/GFZ.3.7.2022.001