On October 28, 2025, the research vessel Elisabeth Mann Borgese departed from Rostock for this year's autumn monitoring expedition EMB379 in the Baltic Sea. On board: a 12-people interdisciplinary IOW team of researchers, laboratory and technical staff who will carry out the measurements and sampling.

During the 16-day research cruise aboard the Elisabeth Mann Borgese, samples will be taken at around 100 stations from the western to the central Baltic Sea. The work program includes the collection of hydrographic and chemical data as well as biological samples, which will be used to document the state of the Baltic Sea ecosystem in fall 2025 and contribute to our understanding of the ecosystem on longer time scales. The expedition is led by IOW oceanographer and geologist Michael Naumann.

The expedition is part of the IOW monitoring and long-term data program, which has been launched in 1969 and was officially recognized by the United Nations as a project of the “UN Decade of Ocean Science for Sustainable Development” in 2024. Five monitoring trips are carried out each year, and as part of the annual autumn monitoring program, e.g. benthic samples are collected for the BSH in the western Baltic Sea.

This year, doctoral student Laura Pareigis from the Max Planck Institute for Marine Microbiology (Bremen) is accompanying the expedition and takes DNA samples in the western Baltic Sea for the sample archive of IOW microbiologist Matthias Labrenz. She will also collect samples in the central Baltic Sea for her doctoral thesis on sugar uptake mechanisms in marine microorganisms.

As part of this year's autumn monitoring program, sediment cores will be extracted in the western Gotland Basin for research by IOW scientists Matthias Moros and Michael Naumann. Analysis of these cores will then enable mapping of the total organic carbon (TOC) in surface sediments in the central Baltic Sea basin. According to Michael Naumann, sampling in the different basins and analysis of these sediment cores will take several years and provide important insights into the deposition rates of organic carbon over the last 70 years.

The route and sampling points for this year's autumn monitoring (Map: IOW/M. Naumann).