Expeditionary works to study the shallow water zone of Lake Baikal, RV “Papanin”, June 03-14, 2023

The works were carried out within the State assignment “Study of seasonal and long-term transformations of the state of water bodies and watercourses in East Siberia in the context of climate change, geological environment and anthropogenic loads” (project № 0279-2021-0005) (led by A.P. Fedotov).

The tasks of the expedition were to study hydrochemical parameters of the shallow water zone, distribution of phyto- and zooplankton and zoobenthos. The average sampling step along the Baikal perimeter is every 30-50 km. Water samples were taken at 10 stations in the coastal zone of Lake Baikal including recreational areas of the coast, unpopulated areas, river mouths, into which treated wastewater is discharged, bays and the Maloye More Strait. Surface water, bottom sediments and biota in the coastal zone were sampled at 21 stations to assess the content of priority organic pollutants (PCBs, PAHs, phthalates) and to analyze alkylbenzene sulfonates.

Despite the fact that the ice-cover in 2023 melted later than usual, drifting ice fields were encountered in the northern part, the bays were warmer than in 2022. Temperature in Mukhor Bay (Maloye More Strait) was 16.5°C and 15.4°C (2022), in Chivyrkuisky Bay – 8.7°C and 5.7°C (2022), in Khakusy Bay – 9.3°C and 7.8°C (2022), and in Aya Bay – 8.2°C and 4.3°C (2022).

According to preliminary data, representatives of the genera Aulacoseira, Synedra, and Stephanodiscus dominated among planktonic diatoms, and species of the genus Dinobryon dominated among golden-backed diatoms.