Aquatic ecosystems are among the most severely impacted ecosystem with excessive biodiversity loss. In particular, overexploitation, chemical pollution, fragmentation, habitat destruction or degradation and invasion by non-native species are the factors that can result in species loss. Therefore, a comprehensive understanding of these factors and the robustness and resilience of aquatic systems is key to developing integrative concepts in aquatic ecology, nature conservation, and water policy. This understanding will be achieved in the research focus „Water“ via a multiscale approach (from the molecule to the ecosystem) and an interdisciplinary and transdisciplinary perspective.