Биоэкологические исследования озера Манжерокское

Bioecological analysis was carried out in the subglacial environment. Water samples were taken both from the subglacial layer (0–20 cm) and from the bottom using a Ruttner bathometer. Dominant spe-cies were identified if their abundance or biomass exceeded 10 %. Using the assigned identifiers, phy-toplankton were taxonomically identified and a Shannon diversity index was estimated using abun-dance. The lake phytoplankton was found to be biologically active due to dominance of cryptophyte flagellates, thus indicating positive environmental factors; the chlorophyll ‘a’ concentration, the main green pigment in water, reached values up to 2.79 mg/m³ in the lake and up to 15.73 mg/m³ in the creek, specific for hypereutrophic waters. Algae abundance in the lake and the outflowing creek reaches significant values from 1500 to 3500 thousand cells per litre of water, due to the high concen-tration of primarily blue-green algae (Microcystis aeruginosa, Microcystis pulverea, Merismopedia punctata, Gloeocapsa magma). The algal biomass is also high, ranging from 7.1 to 15.9 grams per cu-bic metre, excluding sampling point 1, where the values were lower than those indicated. The ecologi-cal state analysis of the under-ice phytoplankton has revealed the lake water to have an alkaline envi-ronmental reaction and increased organic pollution. The most beneficial conditions for vegetation were in the Ozerny creek (Shannon index 5.98 bits/ex).