Analysis of factors significant to zoobenthos of lake Beloe, Vologda region

To obtain comparable data on food value in different types of water bodies, it is necessary to take into account the complex effects of a number of factors (hydrological features, the nature and type of substrate, the presence of aquatic vegetation, etc.). In this study, an attempt is made to analyze the influence of some environmental factors on the quantitative indicators of zoobenthos of Lake Beloe (Vologda Region) using the results of field research in 2010-2020, analysis of topographic maps and remote sensing data of the Earth. In most of the lake's water area, the habitat conditions of benthos are of the same type, which is due to the morphometric parameters of the lake and the gentle slope of the basin, which has a bowl-like shape and a gradual increase in depths. The timing of the onset of phenological phenomena within the navigation pass of the Volga-Baltic waterway is shifted relative to the rest of the lake. The average long-term level regime of Lake Beloe is characterized by relative constancy, while there is no clearly pronounced seasonal dynamics of water level fluctuations, which negatively affects the hydrobionts of the shallow water zone, causing their death in shallow areas. The degree of overgrowth of the water area is 3.6 %, the distribution of macrophyte communities on the lake is uneven (the largest areas of thickets are formed at the confluence of the Kema River and Kovzha River, at the estuary of the Megra River, as well as at the source of the Sheksna River). Benthos of thickets is characterized by average values of biomass, but a high abundance. Zoobenthos indicators of Lake Beloe can be characterized by the state of the benthocenoses of the deep-water zone, the indicator of the sandy littoral zone, the general indicator of the estuaries of rivers and the source of the Sheksna River. The ratio of the area of these biotopes in Lake Beloe, calculated according to a set of characteristics, was 83.3 %, 10.0 % and 6.7 %, respectively. When using the average values of the zoobenthos of Lake Beloe over the past 10 years, the weighted average number is 2539 individuals/m2, biomass - 8.0 g/m2.