Field Research in the Baltic Sea on Cruise 55 of the P/V Akademik Ioffe

New data on the structure of the water column, upper layer of bottom sediments, and biological communities of the Gdansk and Gotland deeps and the Gulf of Finland in the Baltic Sea were obtained on cruise 55 of the P/V Akademik Ioffe (June 29–July 15, 2020). Hypoxic conditions developed below the permanent halocline, disturbed on the eastern slope of the Gotland Deep by inflow intrusions with a moderate oxygen content. Macrozoobenthos was absent in the deep parts of the Gdansk and Gotland Deeps. Cyanobacteria bloom was noted in the surface water layer during the entire expedition.