Scientific publications

As part of the research theme “State of the White Sea Coastal Ecosystem within the Solovetsky Archipelago” (FMEN 2024-0016), measurements were carried out in Blagopoluchiya Bay (Solovetsky Islands, White Sea) on April 5-7, 2025 to identify the characteristics of the snow-ice cover, changes in temperature and salinity, oxygen conditions, and optical properties of water through the tidal cycle during the ice-covered period. The measurements included: (1) ice spatial survey; (2) installation of stand-alone stations for measuring water temperature, pressure and dissolved oxygen at the wastewater discharge site through the tidal cycle; (3) spatial survey of temperature, salinity, dissolved oxygen, and fluxes of photosynthetic active solar radiation over a grid of stations at high and low water. It was found that wastewater with a temperature of +0.3…+0.4 °С and a salinity of 0.3–0.5 ‰ spreads across Blagopoluchiya Bay under ice over a distance of more than 300 m from the discharge point. The wastewater layer at all stations was 0.10–0.15 m thinner at high tide compared with low tide. Below the wastewater layer, there was a mixing layer several tens of cm thick at all stations, in which the water temperature fell to negative values and the salinity rose to 23 ‰. The mixing layer was underlain by a layer of seawater with a temperature of –1.1…–1.2 °С and a salinity of 27.4‰. It was found that the oxygen content in the wastewater (60–70 %) was noticeably lower than outside this layer (90–130 %). A sharp decrease in the solar radiation flux in the wastewater layer and the mixing layer is responsible for the poor illumination of the water column, with solar radiation fluxes close to zero at depths below 2–3 m. At almost all stations, there occurred a significant (approx. 30 % on average) decrease in the extinction coefficient at high tide versus low tide, indicating partial removal of wastewater by the sea tide.