As human populations grow across the planet, water security, biodiversity loss and the loss of aquatic ecosystem services take on ever increasing priority for policy makers. International Review of Hydrobiology brings together in one forum fundamental and problem-oriented research on the challenges facing marine and freshwater biology in an economically changing world. Interdisciplinary in nature, articles cover all aspects of aquatic ecosystems, ranging from headwater streams to the ocean and biodiversity studies to ecosystem functioning, modeling approaches including GIS and resource management, with special emphasis on the link between marine and freshwater environments. The editors expressly welcome research on baseline data. The knowledge-driven papers will interest researchers, while the problem-driven articles will be of particular interest to policy makers. The overarching aim of the journal is to translate science into policy, allowing us to understand global systems yet act on a regional scale.