During the period from July 1 to 10, 2025, specialists from the Ukrainian Scientific Center of Ecology of the Sea (UkrSCES) conducted the third (first for WP3) field campaign within the framework of the international Black Sea SIERRA project, funded by the European Union. The expedition’s objective was comprehensive sampling to assess the ecological status of water bodies in Southern Ukraine under conditions of civil and military pollution.

The field work covered the the Danube Delta, the Dniester and Southern Bug rivers, Khadzhybey and Tylihul lagoons, and the Black Sea (Odesa Bay). The expedition included collection of:
• Sediment samples for research on biogenic substances, plastics, metals, as well as pollutants of both anthropogenic and military origin;
• Biological specimens — phytoplankton, zoobenthos, algae, flowering plants, fish — for analysis of bioaccumulation of toxic substances in trophic chains;
• Sediment cores in Tylihul Estuary at points with high and low impact from combat operations for comparative research of historical and contemporary pollution types.

The collected samples will be used for quantitative assessment of the contribution of pollution caused by russian military aggression to the overall level of anthropogenic pressure on the marine environment, as well as for identifying priority marine ecological risks, particularly threats to coastal biodiversity components of the northwestern Black Sea.

Primary scientific objectives of the research:
• Determine types, sources, and levels of pollution, including bioaccumulation in living organisms;
• Identify new types of pollutants associated with armed conflicts;
• Analyze the hierarchy of risks and threats to marine and coastal biodiversity;
• Conduct quantitative mapping of civil and military pollution distribution.

This expedition is a continuation of previous expeditions conducted in June 2025 and at the end of 2024. By the end of 2025, three more expeditions are planned within the Black Sea SIERRA project. It is expected that these researches will enable the formulation of scientifically substantiated recommendations for risk management and strengthening the ecological security of the Black Sea.

The Black Sea SIERRA project represents a crucial international scientific initiative addressing the environmental impacts of military conflict on marine ecosystems and developing sustainable management strategies for the Black Sea region.

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Funded by the European Union. Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or the European Climate, Infrastructure and Environment Executive Agency. Neither the European Union nor the Granting authority can be held responsible for them.