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Head of Research Group Stable Isotope Biogeochemistry
PD Dr. Michael Dannenmann

PD Dr. Michael Dannenmann

Stable Isotope Biogeochemistry and Center of Stable Isotopes (CSI)

The isotopic ratio of an element reveals information that help us to understand complex ecosystem processes, either by using isotopes as artificially enriched tracers or by quantifying their natural abundance. In this context, our scientific aims are: 

  • to study C, N and H2O cycling of terrestrial ecosystems
  • to quantify biosphere-atmosphere-hydrosphere exchange of environmentally important substances
  • to study effects of global change and anthropogenic management on soil, plant and atmospheric processes.


In addition to standard isotopic analyses, the CSI develops targeted novel analysis and automated sampling tools to meet the analytical needs of IMK-IFU in the fields of biogeochemistry, plant sciences and hydrology. Recent developments include e. g. a new technique to analyze δ15N in the denitrification products NO, N2O and N2.

CSI is a cross-cutting unit and provides its expertise and analytical capacities (analysis of C and N and O isotopes in solid, liquid and gaseous samples) to all divisions of KIT/IMK-IFU and to external scientific partners.




Four Isotope Ratio Mass Spectrometers coupled to

  • Two CN Elemental Analyzers to measure natural abundance or isotopically enriched δ13C and δ15N in solid samples
  • Thermal combustion Elemental Analyzer (TC/EA) for analysis of δ18O and δ2H in liquid and solid samples.
  • Gasbench for analysis of δ13C and δ18O in CO2 and δ15 in N2


Tunable Diode Laser Spectrometer TGA 200 for continuous analysis of the isotopic composition of CO213C and δ18O).


Two Cavity Ringdown Spectrometers L1102-i for simultaneous analysis of δ18O and δ2H of water samples. 



PD Dr. Michael Dannenmann, michael.dannenmann(at)kit.edu (head of CSI)

Allison Kolar, allison.kolar(at)kit.edu (isotope ratio mass spectrometry)