Scientific publications

The results of an analysis of seasonal and spatial variability in water temperature and turbidity, and the concentration of chlorophyll-a in the deep Lake Munozero (Lake Onego catchment) are presented. Analysis of longitudinal sounding data using a CTD-90m multiparameter probe allowed us to analyze the thermal regime of the deep-water northern (depths greater than 35 m) and southern (depths less than 20 m) parts of the lake. Stratification in the deep water northern part lasts longer, resulting in lower oxygen content in the hypolimnion in autumn. A difference in bottom water temperatures was observed between the northern (less than 5 °C) and southern (up to 9.7 °C) parts of the lake, which may impact the benthic community. Water temperature spikes in the lake’s upper layer to extreme 26–27 °C during hot summer weather pose a threat to the lake’s ecosystem, as they can boost the growth of phytoplankton, including toxic cyanobacteria, and can also cause the death of trout in cages. Zones of high water turbidity have been identified in the deep-water northern part of the lake. Seasonally, the layer of high turbidity has been observed to move deeper with the deepening of the seasonal thermocline. High turbidity in the bottom layers of the deep northern basin indicates the accumulation of precipitating suspended matter, which may pose a risk in a lake with a slow flushing rate. The most likely cause of the increased water turbidity in the lake is the activities of the trout farm and tourist facilities.