The Long-term materials on the summer pelagic zooplankton of Lake Vechel’ye (Republic of Belarus) were analyzed. The studies were conducted during the summer months of different years under conditions of thermal stratification of the water column. The sampling station was located at a depth of 33 meters, and samples were collected around noon in late July–early August. Zooplankton was collected in fractions every 5 m from the surface to the bottom. The water temperature in the epilimnion was 22.6±1.7°C, in the hypolimnion — 4.9±0.5°C, and in the metalimnion — 14.6±0.4°C. The water temperature ranged from 3.2±0.8 to 8.8±0.8 degrees. A total of 48 zooplankton species were identified, including Rotifera (25 species), Copepoda (9 species), and Cladocera (14 species). The average zooplankton density in the water column was relatively low for typical mesotrophic lakes, amounting to 28.3±13.9 thousand ind./m³, ranging from 50.3 to 17.6 thousand ind./m³. The population was dominated by Copepoda (65.9±8.2%), Cladocera (19.8±4.3%), and Rotifera (14.3±6.7%). High density was observed in the epilimnion and metalimnion, while the minimum was recorded at a depth of 20–25 m. Cladocera were concentrated in the upper layers, whereas Rotifera and Copepoda were concentrated in the metalimnion. The average daytime depth of zooplankton distribution was 11.45±1.0 m. Among the rare species, the relict cold-water representative Eurytemora lacustris (Poppe, 1887) was found in the hypolimnion.
lake Vechelye, zooplankton, vertical distribution, rotifera, copepoda, cladocera
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