Oceanological Research on High Latitude Transects Near the Spitsbergen Archipelago during the Period of Polar Night

In November–December 2023, an expedition of the Murmansk Marine Biological Institute of the Russian Academy of Sciences, on board the R/V Dalnie Zelentsy conducted hydrological, hydrochemical, hydrobiological, and radioecological research in the area west of the Spitsbergen archipelago and on the century-old Kola Meridian transect in the Barents Sea. New data on thermohaline conditions, plankton, and radionuclides during the polar night were obtained at 54 oceanographic and hydrobiological stations. Positive water temperature anomalies show continuation of the warm climate cycle in the Barents Sea. The revealed activation of florogenesis in the western Barents Sea is probably caused by advection of Atlantic waters. Based on an analysis of the population structure of Calanus finmarchicus and C. glacialis in the waters of Spitsbergen, a specific feature of seasonal size variability of species in summer and winter was determined.