Ecological state of water bodies under the influence of natural and anthropogenic factors

Abstract

The article studies the ecological state of two neighboring lakes Sredniy and Nizhniy Pert on the Bolshoy Solovetsky Island after their separation by a dead earthen dam during the construction of the lake-channel system. The studies were carried out in July 2021. It was revealed that these anthropogenic changes led to a change in the regime of lakes, especially Nizhniy Perth, which lost its flow. Samples of water and bottom sediments were taken from the deep waters of these reservoirs. In these samples, the main hydrochemical parameters were determined, and bottom sediments were studied for the content of moisture, iron and sulfur, organic carbon and nitrogen in them. A difference was noted in the water color of the studied lakes, which is due to anthropogenic influence and the isolation of water bodies, and in their mineralization, which is associated with the location of water bodies relative to the White Sea. A greater amount of organic matter (carbon) was found in the water and bottom sediments of the lake. Sredniy Perth, therefore, in the bottom layer of the water column of this reservoir, a lower oxygen content was noted compared to the neighboring lake, while in none of them did anaerobic conditions arise in the water. The C/N ratio in the sediments indicated a greater contribution of the allochthonous pathway of organic matter inflow into both lakes, and this was slightly more pronounced in the less flowing lake Nizhniy Perth. A difference in the granulometric composition of the sediments of the studied reservoirs was revealed, which is associated with a change in hydrochemical regimes and different sedimentation conditions as a result.