The Knowledge Flow Paper on hand is linking a problem-oriented discourse field analysis to the broader subject of climatically caused changes of freshwater systems and their biodiversity. This synthesis is a first step towards a better understanding of the impacts of climate change on biodiversity in freshwater systems, which are too little investigated and understood compared to terrestrial ecosystems. Following a brief introduction of the method, the main arenas are being presented and in a second step strands of discourse will be identified. The aim of the analysis is to identify priority issues, key actors and their positions, to distinguish undisputed knowledge of contested knowledge as well as to point out possible future research questions – as formulated by the actors or deduced from analysing contested knowledge. Finally, we will draw conclusions within this field of climatically caused changes of freshwater ecosystems to provide an orientation for a further involvement of the research centre in cross-cutting issues and aims of intervention into the discourse.