PhD Candidate in Tropical Geomicrobiology / PhD Candidate in Tropical Geomicrobiology

PhD Position in Tropical Geomicrobiology: Modern and Ancient Microbial Drivers of Biogeochemical Cycling

100%, Zurich, Fixed-Term

We are seeking a highly motivated PhD student for a multidisciplinary project spanning two groups. The Sustainable Agroecosystems (SAE) group in the Department of Environmental Systems Science at ETH Zurich is dedicated to bringing healthy food from fields to tables worldwide for generations to come. Meanwhile, the Surface Earth Evolution (SEE) group in the Department of Earth and Planetary Sciences focuses on investigating the processes that drive global climate change over both human and geological timescales. Together, our research integrates traditional Earth and environmental science fields to study the drivers and impacts of changing climate and land use. We aim to holistically analyze these aspects through effective field-based sample collection and lab-based biogeochemical measurements.

Project Background

This position is part of the SNSF-funded project titled Constraining tropical wetland greenhouse gas production today and through time: insights from Tumba-Ngiri-Maindombe, Democratic Republic of Congo (Lac Mai). The project aims to mechanistically assess the climatic and anthropogenic controls on greenhouse gas emissions (i.e., carbon dioxide, methane, and nitrous oxide) in Tumba-Ngiri-Maindombe, a critically understudied region housing the world's largest tropical wetland. To achieve this, we will collect samples of greenhouse gases, peatland soils, and lake sediments, and analyze these using isotopes, biomarkers, and DNA-based methods.

The PhD student will lead the microbial component of this interdisciplinary project. Utilizing state-of-the-art molecular techniques, you will identify the microbial drivers and metabolic capacity in tropical lake sediments while reconstructing their evolution in response to climatic shifts over the past 12,000 years (i.e., the Holocene).

Job Description

• Fieldwork: Participate in sampling expeditions to DR Congo to collect high-resolution, pristine sediment records from Lake Mai Ndombe and surrounding peatlands, ensuring proper preservation for molecular and biological analyses.
• Contemporary Microbial Profiling: Perform DNA extraction, qPCR, and ribosomal metabarcoding on surface sediments. Quantify key functional marker genes (e.g., mcrA, pmoA, nosZ) and identify extant microbial drivers of modern carbon and nitrogen cycles.
• Ancient DNA Analysis: Execute specialized DNA extraction from deep sediment cores under rigorous contamination controls. Utilize shotgun metagenomics to reconstruct the structural and functional adaptation of microbial communities to paleo-environmental shifts.
• Integrative Bioinformatics: Process complex sequencing datasets using advanced computational pipelines. Perform taxonomic profiling and metabolic reconstruction to link microbial drivers with fluctuating environmental parameters from sediment records.
• Communicate Findings: Attend international conferences and workshops and write scientific papers.

This position is integral to the research team, which includes two PhD students, two senior scientists, and several technicians across the two research groups. While you will lead these tasks, you will receive support from all involved researchers. This multidisciplinary team provides an opportunity to learn, develop, and apply scientific skills beyond conventional geomicrobiology.

Profile

• Education: MSc degree in (geo)microbiology, molecular ecology, or a related field.
• Wet-lab Experience: Solid experience in molecular biology techniques (e.g., DNA extraction, PCR, qPCR, sequencing library preparation). Prior experience in an ancient DNA facility or a similarly controlled 'clean lab' is a strong asset.
• Computational Skills: Experience analyzing amplicon and metagenomic data is highly desirable.
• Remote Fieldwork: Willingness to conduct fieldwork in a remote tropical environment.
• Communication: Proficiency in written and spoken English and ability to communicate in a cross-cultural environment.
• Knowledge of French: A plus for fieldwork.
• Personal Attributes: Ability to work independently with flexibility, critical thinking, and a willingness to learn new skills.

Workplace

The workplace is located in a vibrant environment that encourages scientific collaboration and innovation. We foster a welcoming culture that values diversity.

We Offer

• A fully funded 4-year PhD position embedded in the SAE group.
• The opportunity to work in a unique, understudied region of high scientific and climatic importance.
• Excellent, inclusive working conditions, a strong international network, and a competitive salary paid according to ETH standards.

We Value Diversity and Sustainability

In alignment with our values, ETH Zurich promotes an inclusive culture. We advocate for equality of opportunity, appreciate diversity, and maintain a work and learning environment that respects the rights and dignity of all staff and students. Sustainability forms a core value for us as we are committed to advancing toward a climate-neutral future.

Curious? So are we.

We look forward to receiving your online application using the form below. Please ensure that your submission aligns with the job profile, as only applications matching the job criteria will be considered.

For your application, please include:

• Curriculum Vitae detailing your educational history, publications, awards, etc.
• BSc and MSc transcripts (in English or German).
• Motivation letter (~2 pages) outlining your interests and relevant experience.
• Contact details of two references.

The start date for this position is ideally June-July 2026. Questions regarding the position should be directed to Dr. Martin Hartmann at martin.hartmann@usys.ethz.ch.

About ETH Zurich

ETH Zurich is one of the world's leading universities specializing in science and technology. Renowned for our excellent education, cutting-edge research, and the direct transfer of knowledge into society, we host over 30,000 people from more than 120 countries. Our university nurtures independent thinking and inspires excellence, working together to tackle today's and tomorrow's global challenges.