As an aspiring researcher, would you like to contribute to understanding the key role that microorganisms play in controlling Earth’s biogeochemistry? As a PhD candidate, you will further explore the critical role of sharp redox transitions in marine environments for the removal of toxic ammonium and greenhouse gas methane. An interdisciplinary project, with far-reaching implications for a wide range of research fields.

Coastal ecosystems are of vital importance to mankind. Due to increased nutrient loads, and climate change these ecosystems experience frequent seasonal hypoxia leading to release of greenhouse gases. In the ERC Synergy project MARIX, we focus on the discovery of new microbial and geochemical pathways for the removal of methane and ammonium. In this ERC project, we are exploring the redox reactions, microbial players and key controls that explain this removal.

The MARIX project combines sea-based fieldwork with laboratory experiments and reactive transport modelling. You will focus on sediment processes in a range of field work areas including the Netherlands and Sweden. A key goal will be to increase the understanding of processes leading to the anaerobic removal of methane and ammonium coupled to reduction of iron oxides and interactions between the nitrogen, methane and iron cycles.

The MARIX team and collaborating research groups currently consist of several PhD candidates and postdoctoral researchers and complementary staff members. Your teaching load may be up to 10% of your appointment.  We have in total 3 positions available.


  • You hold an MSc degree in Life or Earth sciences (biology, microbiology, biotechnology, biogeochemistry, molecular life sciences, environmental sciences, or environmental engineering). 
  • You have good communication skills and are able to operate in a dynamic international research team.
  • You have a good command of written and spoken English.
  • You are willing and able to develop yourself into an independent scientist (growth mindset).
  • Knowledge of basic microbiological or biogeochemical methods is essential.
  • Experience in anaerobic or environmental microbiology and/or fieldwork would be an advantage.
  • Experience in inorganic geochemistry and quantitative modelling is helpful, but not a requirement.

We are

The Microbiology cluster is world-leading in environmental microbiology and has won many prestigious awards including three ERC Advanced Grants, an ERC Synergy Grant, a Spinoza prize and two Gravitation Grants. The cluster is part of the Radboud Institute for Biological and Environmental Sciences (RIBES), Faculty of Science, Radboud University. We offer a dynamic research environment with a strong international profile, state-of-the-art laboratory infrastructure, strong national and international collaborations, and the possibility to further develop both scientifically and professionally with a large variety of courses, training and conferences. Radboud University is an equal opportunity employer, committed to building a culturally diverse intellectual community, and as such encourages applications from women and minorities.

Radboud University

We want to get the best out of science, others and ourselves. Why? Because this is what the world around us desperately needs. Leading research and education make an indispensable contribution to a healthy, free world with equal opportunities for all. This is what unites the more than 24,000 students and 5,600 employees at Radboud University. And this requires even more talent, collaboration and lifelong learning. You have a part to play!

We offer

  • It concerns an employment for 1.0 FTE.
  • The gross starting salary amounts to €2,541 per month based on a 38-hour working week, and will increase to €3,247 in the fourth year (salary scale P).
  • You will receive 8% holiday allowance and 8.3% end-of-year bonus.
  • You will be employed for an initial period of 18 months, after which your performance will be evaluated. If the evaluation is positive, the contract will be extended by 2.5 years (4 year contract).
  • You will be able to use our Dual Career and Family Care Services. Our Dual Career and Family Care Officer can assist you with family-related support, help your partner or spouse prepare for the local labour market, provide customized support in their search for employment and help your family settle in Nijmegen.
  • Working for us means getting extra days off. In case of full-time employment, you can choose between 29 or 41 days of annual leave instead of the legally allotted 20.

Additional employment conditions

Work and science require good employment practices. This is reflected in Radboud University’s primary and secondary employment conditions. You can make arrangements for the best possible work-life balance with flexible working hours, various leave arrangements and working from home.

You are also able to compose part of your employment conditions yourself, for example, exchange income for extra leave days and receive a reimbursement for your sports subscription. And of course, we offer a good pension plan. You are given plenty of room and responsibility to develop your talents and realise your ambitions. Therefore, we provide various training and development schemes.

Would you like more information?

For questions about the position, please contact Mike Jetten, Professor at Alternatively, you can contact Caroline Slomp, Professor at

Practical information and applying

You can apply until 14 September 2022, exclusively using the button below. Kindly address your application to Mike Jetten. Please fill in the application form and attach the following documents:

  • A letter of motivation.
  • Your CV including the contact details of two knowledgeable references.

The selection procedure will comprise two interview rounds: an online interview at the end of September and an on-site interview at the beginning of October.

You would preferably  begin employment as soon as possible.

We can imagine you’re curious about our application procedure. It offers a rough outline of what you can expect during the application process, how we handle your personal data and how we deal with internal and external candidates.

Apply now

Application deadline 14 September 2022

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