Scientific publications

The article analyzes seasonal patterns in the vertical distribution of zooplankton in areas of Kondopoga Bay of Lake Onego with different depths and trophic conditions. The analysis was based on data from net catches of zooplankton in 1988–2021 (130 stations, 386 samples). Average multiannual seasonal trajectories of the indicators were obtained by movingaverage smoothing of the data series collapsed by seasonality (day since the beginning of the year). The main focus was on seasonal variations in the distribution of zooplankton in the water column. The temperature regime affecting the timing and scale of water stratification is considered as one of the leading factors of the vertical heterogeneity of the medium. The growing season is divided into three stages according to the type of zooplankton distribution: spring, summer and autumn. The general patterns of zooplankton distribution are similar in the open deepwater area of Lake Onego (depth 75–100 m) and the central part of Kondopoga Bay (depth 75–80 m), and correspond to changes in the vertical heterogeneity of the water column. Due to shallowness (up to 17 m) and relative proximity of wave mixing, the distribution of zooplankton in the bay head has some specific features. In early August, the water column is mixed and the vertical distribution of zooplankton is leveled out. A comparison of the dynamics of zooplankton abundance in areas with different trophic conditions showed that the general patterns in the surface layer are similar, but the seasonal trajectories in the deeper layers vary. In summer, zooplankton biomass in the bay was 2-3 times that of the lake’s open part. The study of the seasonal variation of the vertical distribution of zooplankton in the water column will provide insights into the patterns of pelagic plankton functioning in years with different temperature conditions, which is relevant under climate change.