Coasts and deltas are “hot spots” for biodiversity. These environments, subject to global changes, constitute sensitive ecosystems whose management requires a long-term understanding of the mechanisms of formation and functioning. Since 2010, an international research project has been attempting to reconstruct the evolutionary trajectories of one of the largest hydrological complexes: the Lower Danube and its delta. The Franco-Romanian team initiated a research project focusing on the study of agro-pastoral communities that inhabited the Danube Delta during the 5th millennium BC. This project focuses on the relationships between the Chalcolithic societies of Gumelnița culture and their environment. In the particular context of the Danube Delta, these communities have been exposed to sudden environmental changes, and more specifically to changes in the hydrosystem. The excavation of the submerged tell of Taraschina, now located in the center of the Danube Delta, is being carried out with a view to rebuilding the link between societies and their environment. In particular, the link between geomorphological – bio-geographic – mobility and adaptation strategies of human communities must be observed. Archaeological horizons provide data that allow us to reconstruct, at high temporal resolution, the impact of these communities on their environment and biodiversity. At the local level, archaeozoological studies dedicated to invertebrates (bivalves and snails) and vertebrates (fish, reptiles, birds, mammals), palynological studies and the analysis of phytoliths have provided very important information to reconstruct the environments and their exploitation. Thus it was possible to highlight cereal processing practices at the Taraschina site and in its surrounding environment. Archaeological data show a succession of crises during the second half of the 5th millennium BC (around 4350-4250 BC and around 4150-4050 BC). https://www.sust-black.ro