University of Freiburg

The Applied Geochemistry group is offering a PhD position at the Institute of Earth and Environmental Sciences, University of Freiburg (Germany). Our group studies element cycling in soils, sediments, and surface waters using an interdisciplinary approach, with a focus on environments affected by human activities and climate change.

Project background

Sulfur cycling is a fascinating but still surprisingly understudied part of wetland biogeochemistry. In oxygen-limited environments such as peatlands, the Wadden Sea, and other wetlands, sulfate can be rapidly transformed into sulfide. Sulfide, in turn, reacts strongly with iron minerals and can promote the dissolution of Fe(III) oxides, setting off a cascade of reactions that influence both iron and carbon cycling.

Despite its importance, many aspects of sulfur cycling in terrestrial wetlands remain poorly understood. One reason is that sulfur compounds are unstable, making them difficult to capture with conventional analytical methods.

This PhD project will investigate sulfur redox transformations in wetlands and their links to iron and carbon cycling. The project combines experimental work with analytical method development to characterize different sulfur species using techniques such as HPLC and LC-ICP-MS. The project also offers the opportunity for fieldwork in the Black Forest, where the PhD candidate will investigate sulfur pools and transformations in minerotrophic peatlands.

Tasks and Responsibilities

• Design and conduct laboratory experiments
• Apply and develop analytical methods for sulfur speciation
• Acquire and analyze synchrotron-based research data
• Identify suitable field sites in the Black Forest and establish contact with landowners and relevant authorities
• Publish research results in peer-reviewed journals and present them at conferences
• Contribute to teaching and supervise laboratory practical courses

Requirements

• A degree (MSc or equivalent) in environmental science, geoecology, environmental chemistry, geomicrobiology, or a related field
• Strong motivation for interdisciplinary research
• A collaborative mindset, scientific curiosity, and willingness to travel for field campaigns and networking events
• Strong interest in environmental geochemistry and analytical method development
• Excellent command of written and spoken English; knowledge of German is an advantage
• A driver’s license (B) is beneficial

We offer

• An engaging and supportive working environment that fosters scientific curiosity, creativity, and interdisciplinary collaboration
• Access to state-of-the-art research facilities in our newly equipped laboratory
• Opportunities to attend and present your research at national and international conferences
• Close scientific supervision and comprehensive onboarding into the research group

Applications should be submitted through the University of Freiburg job portal on https://uni-freiburg.de/en/job/00005154/ and should include a CV, a motivation letter, copies of relevant degree certificates and contact information for two references.

Applications will be reviewed starting early October 2026, and the position will remain open until filled. The ideal start date is November 2026 or as soon as possible thereafter. Employment follows University of Freiburg regulations (TV-L A13, 70%). The position is limited to 3 years.

For informal inquiries about the position or questions related to then project please contact:

Prof. Dr. Kerstin Hockmann

info@geochem.uni-freiburg.de

Applied Geochemistry

Institute of Earth and Environmental Sciences

Albertstraße 23b

79104 Freiburg im Breisgau, Germany

Phone: +49 761 203 6404

Additional information about the University of Freiburg and our research is available at https://uni-freiburg.de/unr-geochem/.