Floodplains are periodically flooded, which makes scientific working difficult. Hence, these highly dynamic ecosystems have not yet been investigated extensively with regard to greenhouse gas (GHG) fluxes. The National Park “Donau-Auen“ is the biggest semi-natural floodplain forest in Central Europe. The periodic input of nutrients and the continuous supply with water safeguards the diversity and productivity of the forests. These conditions are at the same time perfect requirements for the production of greenhouse gases harmful to the climate, such as nitrous oxide (N2O) and methane (CH4). Floodflux trace the GHGs and environmental conditions at several representative locations, to understand the underlying processes of GHG formation and uptake. The objective of the project is to determine the impacts of periodic flooding on GHG emissions throughout the national park forests. The project will therefore deliver important ideas for improvement of greenhouse gas inventories in (floodplain) forests. The results will furthermore give important insights to improve current strategies on climate change adaptation.