Hydrochemical Characteristics of Lakes of Different Types on the Bolshoi Solovetskii Island

Abstract

Comprehensive hydrochemical studies of nine lakes of different types on the Bolshoi Solovetskii Island (Arkhangelsk region) were carried out (July 2022). The choice of the objects was determined by the morphometric features of the water bodies, their remoteness from the sea, and the possible anthropogenic load on them. The main hydrochemical characteristics were determined, including the temperature, electric conductivity/TDS, pH, color, alkalinity, ionic composition, hardness, and the concentrations of oxygen, hydrogen sulfide, organic carbon, nutrients, heavy metals, and methane. Water hardness was found to be low with chloride and sodium ions dominating in its TDS. The hydrochemical conditions are shown to be generally favorable for biogeochemical processes. At a low and medium concentration of organic mater (from 8 to 30 mg/L), humic acids dominated in its composition, determining a higher color index of water (except for the Nizhnii Pert Lake). By their trophic level, the examined lakes were classified as oligotrophic (one of them is dystrophic), mesotrophic, and eutrophic. The anthropogenic load determined the status of a mesotrophic water body, and the high trophicity was determined by natural factors (the swampiness of catchment areas and their relatively recent separation from the sea).