Hydrophysical expedition onboard the RV “G.Yu. Vereshchagin”, July 16 - 29, 2020

The expedition within the framework of the program “Assessment and Forecast of the Ecological State of Lake Baikal and Adjacent Territories under Conditions of Anthropogenic Impact and Climate Change” and “Ecological and Economic Assessment of Functioning of Freshwater Biogeocenoses: Fundamental and Applied Aspects” were carried out onboard the RV “G.Yu. Vereshchagin”, July 16-29, 2020.

The aim of the expedition was to assess the impact of natural and anthropogenic factors on the changes in the abiotic and biotic characteristics of the Baikal ecosystem, which determine the quality of its water.

The fieldworks were carried out in three basins of Lake Baikal as well as in Barguzin and Chivyrkuy bays and the Maloye More Strait. During the expedition, samples were taken along the standard grid of stations at fixed layers from the surface to the bottom using a Carousel SBE-32 Water Sampler equipped with 24 bathometers of 5 l each. Samples were taken for chemical analysis and to study the spatial distribution of dominant species of microalgae. Sampling was carried out at 51 stations, the Juday net was used for sampling at 35 stations. Hydrophysical measurements were carried out at 86 stations using an SBE-25 high-precision CTD probe with additional sensors for dissolved oxygen, transparency and suspended matter concentration. Totally, 232 samples were taken for hydrochemical analysis, 481 samples – to determine methane concentration and 247 samples – to study phytoplankton.

Along the RV route, the surface water temperature was recorded, and seepages of gas bubbles were monitored using a hardware and software complex based on the Furino echo sounder with a recording of echogram data. At the “Uzur Cape” hydrometeorological site, hydrostatic pressure sensor for measuring water level in the lake was repaired. An experiment with current profiler was conducted at the site of manifestation of a ring structure near Nizhneye Izgolovie Cape.