PhD position in “Natural radioactivity of nodules and sediments: potential drivers and implications for human safety” (d/f/m/x)

Background
This PhD position is part of the international collaborative research project “Assessing the environmental impacts of deep-sea mining of polymetallic nodules and seafloor massive sulphides“ (MiningImpact3). Funding for the German contribution is provided by the Federal Ministry for Research, Technology and Space (BMFTR). MiningImpact is the leading international research project investigating the environmental impacts of future deep-sea mining (DSM). Since its start in 2015, it has delivered independent scientific research output and significantly improved our knowledge of polymetallic nodule ecosystems in the Clarion-Clipperton Zone (CCZ) and the Peru Basin and their responses to anthropogenic disturbances.

The PhD project will follow and build on the recent finding that the outer layer of polymetallic nodules can be a strong emitter of natural alpha radiation with potential risks for human health (Volz et al., 2023). The spatial distribution and variability of radionuclide abundance in polymetallic nodules and surface sediments will be investigated systematically – ranging from the distribution within individual nodules and surface sediments at selected sites to large-scale patterns over larger areas within the CCZ.

Your Tasks

• Analysis of geochemistry, natural radionuclide content, pore waters and solid sediment phases in polymetallic nodules and surrounding surface sediments collected from different areas in the Clarion-Clipperton Zone (CCZ) in the Northeast Pacific Ocean
• Mapping the spatial variation of ²³⁰Th, ²²⁶Ra and ²³¹Pa in both polymetallic nodules and surface sediments based on existing data and on data obtained from additional samples collected during planned CCZ expeditions
• Connecting the observations to biogeochemical and depositional characteristics in the different areas to identify the factors that are controlling radionuclide enrichment and its observed spatial variability both in the nodules and surface sediments
• Constructing a risk map that addresses the implications of nodule radioactivity for human health
• Working in an interdisciplinary and international team of inorganic and organic geochemists, biogeochemists, microbiologists, geophysicists, petrologists, geologists, oceanographers and modellers both at the AWI in Bremerhaven and in the framework of the MiningImpact3 project consortium
• Using an extensive set of samples and state-of-the-art sampling and laboratory equipment and instrumentation (e.g. SF-ICP-MS, ICP-OES, alpha-, beta-, gamma- spectrometry, GC-MS, GC-irm-MS, microscale AMS for radiocarbon analysis, lab for sequential sediment extractions- as required)
• Contributing actively to novel and innovative research in marine geochemistry and natural radioactivity

Fields

• Geochemical studies of polymetallic nodules as well as sedimentary pore water and the solid phase
• Natural radionuclides / Natural radioactivity
• Early diagenesis and formation of authigenic minerals in deep-sea environments
• Quantification of geochemical and biogeochemical processes 

Your Profile

• Master in geology, geosciences, geochemistry, geophysics, or a closely related discipline
• Experience and analytical background in (marine)(geo)chemistry and a basic understanding of natural radionuclides
• Good communication skills
• High degree of motivation and independence and the ability to work well in a team environment
• Willingness and ability to work in a lab environment, adhering to strict safety rules
• Willingness and ability to participate in seagoing expeditions
• Very good English knowledge (approximately equivalent to CEFR level C1)

Preferred Qualifications and Skills

• Experience in handling and visualising spatial data
• Experience in data analysis with R, Python, Matlab or similar
• Experience in seagoing expeditions
• Experience in analysing or interpreting radioisotope data

Further Information

• Contact in day-to-day work: with up to 5 people 
• Communication: predominantly internal (with colleagues and other departments) 
  in the following ways

1. By telephone: frequently (daily or several times a week) 
2. E-mail: frequently (daily or several times a week) 
3. Video conferencing (e.g. Webex): occasionally (several times a month) 
4. Personal contact in presence: frequently (daily or several times a week)

• Movement around the workplace: regularly within the building (e.g, between departments or floors)
• Business trips: occasional (several times a year) 
• Expeditions: occur

Please note that the general conditions listed serve as a guide and may vary depending on the specific area of application.

For further information on the specific position, please reach out to Dr Walter Geibert (walter.geibert@awi.de; +49 471 4831-2418) and Prof Dr Sabine Kasten (sabine.kasten@awi.de; +49 471 4831-1936). If you have any general questions about the application process, our Recruiting team will be glad to support you – please contact Elisabeth Wildt (bewerbungsmanagement@awi.de, +49 471 4831-2236).

In this overview you will find further contact persons for various matters.

This position is limited to 3 years. The salary will be paid in accordance with the Collective Agreement for the Public Service of the Federation (Tarifvertrag des öffentlichen Dienstes, TVöD Bund), up to salary level 13 (66 %). The place of employment will be Bremerhaven.

All doctoral candidates will be members of AWI’s postgraduate program POLMAR or another graduate school and thus benefit from a comprehensive training program and extensive support measures. 

We offer

• Excellent research environment with access to globally unique infrastructure, comprehensive datasets, and international expeditions
• Opportunity to develop and pursue independent scientific ideas and innovative research approaches addressing societally relevant questions
• Close scientific collaboration and interdisciplinary cooperation within the institute as well as with national and international partners
• An international working environment with daily interaction with colleagues from around the world
• Opportunities for professional and personal development
• Flexible working hours and the possibility of mobile working for up to 50% of regular working hours
• Annual special payment in accordance with the German public sector collective agreement (TVöD Bund)
• Occupational health promotion and company fitness programme with Hansefit
• Support services and an established culture promoting work–life balance, e.g. through our family office offering childcare services (e.g. holiday programmes) as well as advice on family and care responsibilities
• Occupational pension scheme (VBL)

AWI values diversity and actively promotes gender parity, as well as an open, inclusive environment that provides equal opportunities. We are convinced that diverse teams and a variety of perspectives enrich our work and our daily collaboration. In a continuous process of learning and reflection, we aim to ensure that all our employees can be themselves and feel a sense of belonging. We welcome applications from qualified people regardless of binary and non-binary genders, race and nationality, ethnic and social background, religion, age, disabilities, neurodivergence, sexual orientation, and other identities.

Applicants with disabilities will be given preference when equal qualifications are present.

AWI fosters work-family compatibility in various ways. And as a new international member of our team, you can be sure that we will help you settle in. Our Family Office and International Office will be glad to support you, even before you start at AWI.

We look forward to your application!
Please submit your application online only by May 21^st, 2026. An application should include a letter of motivation, a CV, relevant documents, and the names of two potential referees. We kindly ask you to apply in English. No photo is required – we value your qualifications and experience.

Reference number: 26/44/D/Geo-b

Apply through the following website: https://jobs.awi.de/Vacancies/2180/Description/2

More information at: https://www.awi.de/en/work-study/jobs/job-offer.html