University of Lausanne, Faculty of Geoscience and the Environment, Hydrology group

Working at the Faculty of Geoscience and the Environment

• A friendly and cohesive culture at the Institute of Earth Surface Dynamics (IDYST) including 1-day Summer and Winter retreats, usually in the Alps
• A shared office in the pleasant Géopolis building, on campus
• Fully-funded personal research equipment (laptop, desktop computer, monitor, etc.) and research-related travel (conferences, collaborations, etc.)
• Opportunity for co-supervision of the Ph.D. program by a second Principal Investigator
• International collaboration network and opportunities to spend research periods abroad
• Opportunity (but no obligation) to attend doctoral schools and take classes
• Access to laboratories and platforms (analytical platform, geochemistry, stable isotopes) as well as workshops (wood, metal, 3D print)
• Support in your future career choices, through the IDYST Careers group and Graduate Campus activities
• Access to UNIL Campus facilities (Sports center, restaurants, etc.)
• 5 weeks of paid holidays (in addition to 1 week of national holidays) and Paid Parental leave
• The University of Lausanne is committed to equal opportunity and stands firm against all forms of discrimination.

Homepage: https://www.unil.ch/fgse/en/home.html

Tracing vegetation impacts on watershed hydrochemistry

Droughts and water shortages are becoming more frequent and severe, with important consequences for water quality and ecosystem functioning. One emerging observation is that the chemical composition of soil and stream waters changes markedly during prolonged dry periods, potentially serving as an indicator of ecosystem response to stress. This Ph.D. project aims to unravel the mechanisms underlying these changes, and to improve our understanding of how ecosystem functioning propagates into watershed-scale effects.

The Ph.D. candidate will design and perform a series of experiments at the Unil Ecotron facility, to investigate how vegetation regulates soil water fluxes and geochemical reactions, especially during dry periods. The facility already includes a programmable climate chamber with three soil columns and a range of sensors, and additional sensors can be acquired during the project. Depending on the candidate’s interests and skills, the work may combine a range of methods, including analyses of major and trace elements, measurements of vegetation activity, tracer experiments and hydrogeochemical modelling.

As climate change increases the frequency and severity of droughts, this Ph.D. project offers the opportunity to understand and anticipate drought impacts on water resources and ecosystem degradation, while developing expertise at the interface of hydrology, soil geochemistry, and ecosystem science.

The position is part of the Swiss-US project DrySpell, a four-year international collaboration investigating how vegetation stress affects river geochemistry. The DrySpell team includes 6 collaborators among Unil, the Institut de Physique du Globe de Paris, and the University of Illinois Urbana-Champaign, providing opportunities for international, multidisciplinary research.

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Your responsibilities

80% of the employment time will be dedicated to research activities; the remaining 20% will be dedicated to teaching assistant and support duties within the institute. You are expected to:

• Design and conduct innovative experiments
• Operate the Ecotron facility and its network of ~80 sensors throughout the project
• Lead scientific articles in international peer-reviewed journals
• Participate in international conferences and project meetings in Lausanne and Paris
• Participate in approximately one week of fieldwork per year at the Critical Zone Observatory of Mt Lozère, France.
• Make your research workflow (data, code, protocols… ) open and reproducible
• Openly discuss research obstacles and seek advice/help in the group
• Actively participate in creating a collaborative and inclusive culture

Desired qualifications

• Background in disciplines like Environmental Science, Soil Science/Physics, Biogeochemistry, Experimental Ecology, Hydrology, Civil/Environmental Engineering, or closely related disciplines.
• Previous experience with experimental work. Examples may include deploying sensors, collecting soil/water/vegetation samples from the field, conducting laboratory analyses.
• Strong quantitative and data handling skills (e.g. in R or Python).
• Good written and spoken English communication skills.
• Knowledge of French is an asset but is not required.

Apply here by 30.09.2026

Applications are only managed through the Success Factor platform. Candidates are required to register to the platform and submit the following 5 documents (in PDF format):

1. Motivation letter (strict max 2 pages), including:
   • Your professional goals in the next 6-7 years, and how this position might further them
   • A ~250-word description of a topic you felt passionate about in the last ~2 years
   • Description of the methods you feel more comfortable with and why (e.g. numerical modeling, sensor deployment, sample collection, lab analysis, statistics, spatial analyses, programming, etc.)
   • A disclosure of how Artificial Intelligence was used to prepare your application
2. Short Curriculum Vitae (max 2 pages)
3. Copy of all university degree certificates and transcripts
4. Copy of one first-author research report (can be a manuscript, a thesis, or an assignment report)
5. Names, affiliations, and email addresses of at least 2 references (e.g. Master thesis advisor, academic staff who have read your work, previous employers)

For any questions, feel free to contact the Hydrology group (hydrology@unil.ch)