PhD position in biogeochemistry/ isotope geochemistry including radiocarbon

The Institute of Geology and Mineralogy at the University of Cologne, Germany, invites applications for a 3-year PhD project in carbon dynamics in arctic permafrost. The position will be based in the Organic Geochemistry & Radiocarbon group, which is part of the interdisciplinary cosmogenic nuclide-dating center CologneAMS.


Rising Arctic temperatures reduce the spatial extent and thickness of permafrost, exposing the freeze-locked carbon to degradation processes that will finally cause its release to the atmosphere as greenhouse gases CO2 and CH4. The extent of the resulting positive permafrost-carbon climatic feedback depends on how fast the ancient carbon stored for millennia in the frozen ground will be degraded. The PhD project aims at 1) characterizing organic and inorganic carbon pools and microbial communities in different permafrost deposits using organic geochemical methods and 2) determining sources of CO2 and CH4 emissions by carbon isotopic analyses. The project involves technical developments/improvements to measure radiocarbon contents of CO2 and CH4. A basic requirement is participation in several expeditions to the Arctic and the ability to work very closely in teams.

Your Tasks

  • Planning and conducting field measurements in Arctic regions including sampling of sediments, measurement of CO2 and CH4 fluxes and soil/sediment sampling
  • Analyzing organic matter composition and microbial communities using organic-geochemical techniques
  • Developing new and improving existing sampling devices (e.g., molecular sieve cartridges, vacuum systems) for 14C analysis of CO2 and CH4
  • Contributing to AMS 14C analysis in collaboration with the nuclear physics group
  • Organizing fieldwork including logistics
  • Data analysis and publishing of results in peer-reviewed journals

Your Profile

  • M.Sc. in geosciences, environmental sciences, chemistry or related subjects
  • Willingness and ability to participate in several 2-6-week long field campaigns to the Arctic (Siberia, Svalbard)
  • Pronounced interest and excellent background in biogeochemical cycles
  • Practical experience in isotope geochemical and/or organic geochemical methods
  • Ability to work self-organized as well as in a team
  • Strong interest in technical and analytical work (including method development)
  • Good knowledge of spoken and written English


The position is limited to 3 years and will start in March/April 2022. The salary will be according to German Public Service Sector salary group TV-L 13, 65%. For further information please contact Prof. Dr. Janet Rethemeyer. As Ph.D. student you will be member of the graduate school of geosciences or another graduate school. The University of Cologne is committed to equal opportunities and diversity.

Application: Please send your application as a single pdf document (including motivation, CV, certificates, names of 1-2 referees) by email to Prof. Dr. Janet Rethemeyer until 20. Jan. 2022.

09 December 2021     Please mention EARTHWORKS when responding to this advertisement.