Features of the hydrochemical characteristics of three neighboring lakes of the Big Solovetsky Island

The results of an assessment of the current state of lakes that previously belonged to one system (Verkhnii, Srednii, and Nizhnii Pert lakes) and were separated more than 500 years ago are presented. The assessment is given based on hydrochemical indicators based on historical and geographical analysis of data, as well as the results of a study carried out in July 2023. Previously, these lakes have not been jointly and comprehensively studied. The Srednii Pert Lake was included into the lake-canal system, and the direction of its water flow changed. The Nizhnii Pert Lake has become less flowy. Only the Verkhnii Pert Lake remained untouched. It is shown that these are small reservoirs of glacial-tectonic origin with a significant maximum depth. Due to the fact that the main sources of ions entering the lakes were precipitation, surface and groundwater, they are characterized by low values of water hardness and major ions content with a predominance of chlorides and sodium in the ionic composition. The study period (July, 2023) was characterized by heavy precipitation, which led to an increase in water levels in the studied reservoirs, but did not disrupt the stratification of lake waters. Aeration of water down to the 0.5-meter bottom layer prevented the activation of processes associated with anaerobic destruction of organic matter. It has been established that the difference in hydrochemical parameters is clearly expressed in Verkhnii and Nizhniy Pert lakes, which are currently not connected with each other, which is determined, first of all, by the characteristics of their drainage areas, in particular, swampiness and flow. The Srednii Pert Lake also differs in hydrochemical parameters from its associated the Verkhnii Pert Lake, as it is strongly influenced by the waters of the western lake-canal system.

Solovetsky Islands, canal system, small lakes, hydrochemical indicators