Uni-Tübingen

P2 Pollutant Turnover in the Groundwater - Stream Transition Zone of Contrasting Lower-Order Sub-Catchments

Principal Investigators

Dr. Marc Schwientek University of Tübingen, Hydrogeochemistry
Prof. Dr. Jan H. Fleckenstein Helmholtz Center for Environmental Research - UFZ, Department of Hydrogeology
Prof. Dr. Tillmann Lüders University of Bayreuth, Department of Ecological Microbiology
Prof. Dr. Martin Elsner TU München, Analytical Chemistry and Water Chemistry

Contact:

Dr. Marc Schwientek

University of Tübingen, Hölderlinstr. 12, 72074 Tübingen

+49 (7071) 29 73559; marc.schwientekspam prevention@uni-tuebingen.de 

Research Questions

More than 50 % of a landscape are drained by first and second order streams. These small streams are typically well connected to groundwater and consequently are primary receptors for diffuse contaminant inputs from sub-catchments. Hence the initial chemical signature of stream water as well as the overall water quality in rivers is largely governed by processes in these lower order headwater streams. Here, the transition zone between groundwater and surface water is commonly rich in organic material and often characterized by steep redox gradients and high biogeochemical activity, providing potentially highly reactive conditions for the turnover of redox-sensitive species such as pesticides and nutrients. This project will evaluate the importance of this transition zone for pollutant transformation and subsequent effects on stream water quality. Specific goals are to

Approach

Spatially highly resolved monitoring of water and solute fluxes using novel online field probes will be coupled to compound- and enantiomer-specific stable isotope analysis and molecular biological tools as integrative indicators of turnover. Field investigations will be complemented by process-based reactive transport models. This interdisciplinary toolbox is depicted in Fig. 1. This unique combination of approaches will help to unravel spatio-temporal patterns of reactivity and turnover for different land uses and hydraulic conditions.

Interdisciplinary toolbox – methods that will be combined to address research questions of P2. „WP“ refers to work package.