Scheme of work in the 48th cruise of the RV Akademik Boris Petrov in the Baltic Sea.

The 48th scientific cruise of the RV Akademik Boris Petrov was carried out from October 29 to November 12, 2021 (15 days) in the territorial waters and the exclusive economic zone of the Russian Federation in the southeastern part of the Baltic Sea.

The purpose of the expedition: obtaining new data on the paleogeography of landscapes in the southeastern part of the Baltic Sea and monitoring the spatial and temporal changes in the abiotic and biotic components of the Baltic Sea ecosystem.

The head of the expedition, Ph.D. D.V. Dorokhov. The expedition was attended by 18 employees of the AO IO RAS (Kaliningrad) and 1 student of the Kant Baltic Federal University (BFU, Kaliningrad). Nine employees of the AO IO RAS are also students of the BFU; they underwent scientific training on board during the expeditionary work.

The main tasks of the expedition:

• selection of bottom sediment columns for stratigraphic interpretation of geophysical profiles;
• selection of surface bottom sediments for lithological mapping;
• bathymetric survey with a multi-beam echo sounder;
• geoacoustic profiling of bottom sediments;
• hydrological survey along repetitive paths;
• water sampling for hydrochemical and hydrobiological analyzes;
• sampling of phytoplankton, zooplankton, ichthyoplankton, macrozoobenthos.

 Scope of performed work 

A total of 1,568 nautical miles were covered. During the cruise, 2680 km of continuous geophysical profiles were completed. Outboard work was carried out at 128 oceanological stations, where 38 STD soundings were carried out, 22 measurements of the sound velocity profile, water sampling at 22 stations, 75 samples of surface bottom sediments, 4 sediment columns with a geological pipe of large diameter, 19 samples of zoo- and ichthyoplankton by plankton networks, measuring the transparency of water at 15 stations and underwater video filming of the bottom at 8 stations. The sampling of sediments and underwater video filming of the bottom were carried out on the basis of the results of geophysical surveys during the 47th cruise of the RV Akademik Boris Petrov.

 Within the framework of events dedicated to the Year of Science and Technology in Russia, a marine internship was conducted on board the vessel with the participation of 10 students of the Kant Baltic Federal University (2 postgraduate students, 2 undergraduate students and 6 undergraduate students), who during the expedition gained experience in conducting geophysical research and complex works at oceanological stations. As part of the internship of students, scientific seminars were also held.