Isotope tracer group

Focus: Determination of drivers of water, nutrient, and contaminant fluxes in catchments

The research encompasses the delineation of nutrient and contaminant sources as well as the recognition and quantification of biogeochemical matter transformations in surface and subsurface catchments across scales by means of stable isotope methods. Natural and anthropogenic radionuclides in concert with stable isotopes of the water molecule are utilized to provide information on water flow paths, on water travel and residence times, and on water exchange between different hydrological compartments for the implementation in conceptual hydrological, hydrogeological and reactive transport models.


Group leader: Prof. Dr. Kay Knöller
Research scientists: Dr. Christin Müller
Dr. Michael Schubert
PhD students: Christina Radtke
Technical staff: Daniela Reichert
Stoyanka Schumann
Sabine Täglich

Research objectives:

  • Delineation of nutrient and contaminant sources in surface and subsurface catchments
  • Recognition and quantification of biogeochemical nutrient transformation and contaminant degradation processes
  • Defining hydrological constraints of matter transformations in surface water catchments across scales and compartments (discharge-concentration-isotope signature-relationship)
  • determination of reservoir size of groundwater bodies as well as assessment of vulnerability and degree of interrelationship between groundwater and surface water
  • temporal and spatial structure of hydrological systems parametrized by natural stable and radioactive isotopes (and other tracer) methods ("dating")
  • Determination of activity concentrations of natural and anthropogenic radionuclides in the environment and their use as an environmental tracer for the investigation of environmentally relevant processes and states
  • Localization, investigation and assessment of increased natural activity concentrations in (fossil) groundwater (water resource management)
  • Regions: Germany (Bode catchment), Austria (Erlauf catchment), Belgium (Geer catchment), Ireland, South Africa, Kazakhstan, Uzbekistan, Tajikistan


  • Water cycle - application for flow path and travel time assessment: water stable isotopes d2H and d18O, 3-H (tritium), 14-C (radiocarbon), radium isotopes, radon-222, available soon: sulfur-35, sodium-22...
  • Nitrogen cycle: ammonium δ15N, nitrate δ15N/δ18O, nitrous oxide α/β δ15N/δ18O
  • sulphur cycle: dissolved sulphur species: δ34S, δ18O, sedimentary sulphur species
  • carbon cycle: dissolved inorganic carbon and solid carbonates: δ13C/δ18O, solid organic matter δ13C/δ18, δ2H, dissolved organic carbon δ13C

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