Oceanological Research in the Baltic Sea during Cruise 68 of the R/V Akademik Ioffe

E. S. Bubnova^a^,*, V. V. Sivkov^a, L. D. Bashirova^a, b, S. V. Aleksandrov^a, b, A. R. Danchenkov^a, b, Yu. Yu. Polunina^a, and E. P. Ponomarenko^a, b

^aShirshov Institute of Oceanology, Russian Academy of Sciences, Moscow, Russia

^bImmanuel Kant Baltic Federal University, Kaliningrad, Russia

*email: Bubnova.kat@gmail.com

Received March 9, 2025

Abstract— In August–September 2024, new data on the distribution of hydrochemical and hydrobiological parameters were obtained in the Russian sectors of the Southeastern Baltic and Gulf of Finland under conditions of summer sea warming exceeding the modern climatic norm. The structure of Quaternary sediments was studied, and a preliminary reconstruction of environmental changes over the past 1000 years was carried out.

Keywords: Gdansk Basin, Gulf of Finland, Quaternary sediments, halocline, Holocene, dissolved oxygen, nutrients, carbonate system, chlorophyll, zooplankton

DOI: 10.1134/S0001437025700614