Fully funded PhD position
The National Centre of Competence in Research NCCR Genesis is a research infrastructure project funded by SNSF focussing on exploring the emergence of life in the Universe. This interdisciplinary research infrastructure brings together physicists, earth and planetary scientists, chemists and biologists to understand the conditions and the mechanisms that enable life to emerge. Developing reliable methods to detect reliable traces of life (biosignatures) – whether through remote sensing or direct onsite measurements – requires significant innovation. These challenges demand close collaboration across physics, biology, chemistry and the earth sciences. NCCR Genesis does not aim
to provide answers in all fields, but to drive innovative research and achieve decisive progress.

Details on NCCR Genesis are available on its website https://nccr-genesis.ch.

Position Overview

The Institute of Earth Sciences (ISTE) at the University of Lausanne invites applications for a PhD position in experimental microbial ecology within the framework of the NCCR Genesis.
The successful candidate will work under the joint supervision of Dr. Alice Bosco Santos (UNIL) and Dr. Nicola Storelli (SUPSI).

Project Overview

This PhD project will develop controlled experimental systems to investigate top-down and bottom-up ecological strategies that directly shape the biosignatures of sulfur-cycling bacteria
in low-oxygen environments. The main focus will be on virus–host interactions in purple (PSB) and green (GSB) sulfur bacteria related to the microbial anoxic communities of meromictic Lake Cadagno. The work will combine laboratory-based experiments at UNIL (Lausanne) and SUPSI (Mendrisio) with field observations in stratified aquatic environments (e.g., meromictic lakes), particularly during June-October. The candidate will generate the empirical foundation needed to quantify how viral perturbations affect microbial metabolism and biogeochemical outputs.

Key Responsibilities:

• Monitoring and Isolation of viruses from the natural environment
• Infection test with different anoxygenic phototrophic sulfur bacteria
• Conduct anaerobic microbiology work, such as maintaining cultures of anaerobic phototrophic sulfur bacteria, designing and performing experiments under controlled redox gradients (e.g., microfluidics, mesocosms).
• Characterize microbial responses using: flow cytometry, viability assays (e.g., live/dead staining), microscopy and spatial analysis
• Develop and apply molecular approaches: qPCR quantification, RNA extraction, and transcriptomics preparation
• Organize and participate in field monitoring campaigns in Lake Cadagno, Ticino, Switzerland
• Contribute to data integration with computational collaborators
  

Candidate Profile
A motivated candidate with a strong interest in environmental
microbiology and geomicrobiology. A master’s (or equivalent) degree in microbiology, environmental sciences, biology, or a related field is preferred. Candidates with an interest in microbial ecology and biogeochemistry and a motivation for fieldwork in lake environments are encouraged to apply.

Working Environment
The candidate will be based at the University of Lausanne within a dynamic, interdisciplinary research environment and will collaborate closely with SUPSI. Time at SUPSI for training and
analysis will be necessary (especially from June to October). The project is embedded in the NCCR Genesis, offering access to a broad network of researchers working on biosignatures, microbial processes, and planetary habitability.

What is Offered

• A fully funded PhD position in Switzerland
• Interdisciplinary training across microbiology, biogeochemistry, and biosignatures
• Opportunities for fieldwork in unique natural systems
• Collaboration within a national research network (UNIL, SUPSI, EPFL)
• A supportive and collaborative research environment within the NCCR Genesis

Application

Applications should be sent to alice.boscosantos@unil.ch and include:

• CV
• Motivation letter
• Contact details of 2–3 referees
• The position is expected to start in Fall 2026. The application deadline is August 5, 2026.
• Interviews will be conducted between August 15 and 20, 2026