EROS 2000: After five years spent in the Gulf of Lions and the Western Mediterranean, EROS 2000 moves East. Western and eastern european scientists decided to pool their efforts together to study the Danube Delta and the North Western Black Sea. This area represents the ultimate example of deterioration of the coastal and marine aquatic environment. It can be viewed as the best pilot site to understand the complex interactions between the human activities and the marine environment. The specific questions adressed by the project will be the followings : 1. What would be the consequences of a reduction of the river input of nutrients for the eutrophication and the ecosystem structure of the north-Western Black sea ? 2. What are the riverine and atmospheric sources, levels and fates of key organic/inorganic pollutants in the Black sea environment ? 3. What are likely to be short- and long-term consequences of the regulation of river discharge for sediment transport/erosion/deposition and water stratification ? 4. What is the significance of the Black sea source of important key greenhouse gases ?