Selected publications

Hydrophilic organic contaminants and per- and polyfluoroalkyl substances (PFAS) are difficult to remove from stormwater runoff. A contaminant transport model was validated to better estimate the removal of contaminants in stormwater filtration systems.

As the hyporheic zone of rivers can be very heterogeneous already at cm-scales, the authors developed an experimental setup to preset short and shallow hyporheic flow paths in the field and to sample pore water. In this experimental setup, the authors were able to study the attenuation of 18 different trace organic compounds wherein the majority were attenuated within the short oxic sections.

Using seasonal, large scale synoptic sampling of stable water isotopes and tritium along the Spree allowed to assess water cycling, storage and losses. The Spree is heavily regulated and drought-sensitive due to high evapotranspiration losses. Such insights are important to adjust water management strategies.

Long-term stream nitrate nitrogen concentrations and concentration-discharge were investigated along the Spree revealing significant heterogeneity in both variables. The upstream parts and winter seasons showed the most serious pollution. Concentrations and relationships are also likely to respond strongly to future droughts, leading to challenges for future land and water management.

This study investigated the mobilisation and transport of particle-associated organic contaminants and their cytotoxicity in a river during storm events. Cytotoxicity determined in cell-based bioassays correlated linearly with total suspended solids concentration in a river, demonstrating that particle-associated contaminant mixtures can strongly affect river water quality during rain events.

The study investigated the impact of streamwater flow velocities and the resulting bedform migration on the CO2 production in streambeds. State-of-the-art 2-dimensional imaging techniques reveal the CO2 distribution in the streambed, an increasing CO2 production in the upper sediment and a decreasing hydrological exchange with deeper sediment layers, with increasing flow velocities.

The study investigated the oxygen budget of 4 arctic lakes using high-frequency data. Incubation experiments measured sediment metabolism. Volume-averaged oxygen depletion in situ was independent of water temperature and duration of ice-cover. Modeling under ice-oxygen dynamics requires consideration of optical properties, biological and transport processes modifying oxygen.

This study applied a tracer-aided ecohydrology model in a data-scarce tropical catchment, using the output of climate models to estimate spatio-temporal dynamics of how water is partitioned, stored and transported at larger spatial scales. This provided a basis for projecting future climate and vegetation changes and the impact on regional hydrological and biogeochemical cycles.