Methane and carbon dioxide distribution and associated microbial communities in bottom sediments of the Kara sea depression
During cruise 96 of the R/V Akademik Mstislav Keldysh in 2024, a sediment core extending to approximately 6 m below the seafloor was collected from the Kara Sea depression. Gas samples from different sediment layers were analyzed for methane (CH4) and carbon dioxide (CO2) concentrations to characterize their depth-dependent distribution. Microbial community composition across the sediment profile was investigated by sequencing, with particular attention to microorganisms involved in carbon and sulfur cycling, including methanogenic archaea (Methanomassiliicoccaceae, Methanoregulaceae, and Methanosarcinaceae), methylotrophic bacteria (Methylophilaceae), and sulfate-reducing bacteria (Desulfobacteraceae, Desulfobulbaceae, and Thermodesulfovibrionaceae).