Worldwide, streams in agricultural landscapes are heavily impacted by diffuse nutrient pollution from the terrestrial surroundings, posing a threat to the ecological integrity of these streams as well as of downstream water bodies due to eutrophication.

The project RIBUST (Riparian BUffer STrips) aims to investigate the potential of riparian buffer strips to mitigate impacts of nutrient pollution and fecal bacteria from agricultural areas on stream ecosystems under current and future climatic conditions.

We are investigating under which conditions riparian buffers strips can efficiently retain nutrients from diffuse sources and whether riparian forests can stimulate the in-stream nutrient uptake capacity through the provision of organic carbon. For this purpose, we are performing field experiments and we are analyzing sediment samples from reaches with and without riparian buffers regarding phosphorus concentrations and adsorption capacities. Furthermore, we are investigating the effects of particulate organic matter on the uptake of reactive inorganic nitrogen and phosphorus by autotrophic and heterotrophic microbial communities and quantifying the effects of temperature on these dependencies.

The results of our project will improve the mechanistic understanding of the stoichiometric control on the nutrient retention and self-purification capacity of streams and will support water managers in the implementation of riparian buffer strips as mitigation measures for diffuse nutrient loads in streams subject to land use and climate change pressures.

The 4-years research project is funded by the Government of Lower Austria.