Hydrographic and oxygen data from Southern Baltic cruises (December 2023 and February 2024) during the 2023/24 inflow event

This dataset contains hydrographic and dissolved oxygen observations collected in the Southern Baltic Sea during two research cruises in December 2023 and February 2024, conducted on board R/V Oceania. The measurements include temperature, salinity, oxygen, and pressure profiles obtained with high-resolution CTD systems along the transect from the Bornholm Basin through the Słupsk Furrow to the Gdańsk Basin. The data capture the hydrographic structure and ventilation signal associated with the 2023/24 inflow event, which introduced saline and oxygen-rich water into the deep basins. These observations provide a basis for analyzing stratification changes, oxygen renewal, and mixing processes during one of the most significant inflows of the last decade.