The Department of Marine Microbiology and Biogeochemistry (MMB; Principal Investigator dr. Darci Rush), is looking for a highly motivated PhD student with a background in organic geochemistry, biogeochemistry, environmental microbiology, or oceanography with an interest in biogeochemical cycling in marine oxygen-depleted systems.

The focus of this project will be on how eutrophication, deoxygenation, and acidification affect microorganisms involved in the carbon and nitrogen cycles. Our focus of attention will be on expanding our knowledge of microorganisms involved in the anaerobic nitrogen cycle. Oxygen-deficient marine waters found underlying productive photic zones such as the Benguela upwelling, and in poorly-ventilated basins, like the Black Sea are expanding in our current ocean climate of increasing temperature and decreasing ventilation. Nitrogen is the nutrient limiting primary production in many parts of the ocean. Under anoxic conditions, nitrogen is lost through denitrifying processes.

The project

The organic geochemical focus in this project will be on, but not exclusive to, bacteriohopanepolyols (BHPs). BHPs are the precursors of the most ubiquitous lipids in the sedimentary record, hopanoids, and are therefore excellent candidates for tracing back past biogeochemical cycling.

This research will be conducted in the framework of the Soehngen Institute for Anaerobic Microbiology SIAM (Gravitation grant ‘Zwaartekracht’, from the Dutch Ministry of Education, Culture and Science, read more here).

The ideal candidate holds an MSc degree in (organic) geochemistry, microbial ecology, marine sciences, chemical oceanography, (analytical) chemistry and/or a related field. Expertise in microbiology would be advantageous.

You are well-organized and methodical in the lab but also willing to get your hands dirty while sampling and analysing natural systems, often under demanding conditions. Fieldwork at sea can be expected during this PhD position.

You are eager to communicate your findings at (inter)national conferences and in peer-reviewed publications.

The inter-disciplinary and international research environment at the Royal NIOZ suits you well, and you have a strong command of the English language in speaking and writing.

Employment of this position at Royal NIOZ is by NWO (The Netherlands Organization of Scientific Research). We offer a position for 4 (fulltime) or 5-years (80%) with an excellent salary, a pension scheme, a holiday allowance of 8% of the gross annual salary, a year-end bonus, and flexible work arrangements.

You may expect very attractive secondary employment conditions. We offer generous relocation expenses for employees coming from abroad and support with finding accommodation.

In the event of equal suitability, preference will be given to female applicants.

The research

Researchers in the Department Marine Microbiology and Biogeochemistry (MMB) aim to understand the crucial role that microorganisms play in regulating global biogeochemical cycles, including primary productivity, carbon sequestration, and the changing climate. To support this research, the Royal NIOZ has a sea-going research fleet to collect marine water column and sediment samples. MMB also offers world-leading in-house analytical facilities for both lipid and molecular techniques.

A key objective within MMB is to shed light on biogeochemical cycling in the dark, deep sea. Within MMB, dr. Darci Rush explores the microorganisms involved in the nitrogen and carbon biogeochemical cycles, with the goal of developing and applying molecular and lipid biomarkers to specific processes key to these cycles. Using lipid biomarkers, we aim to constrain our understanding of past nutrient cycling. However, the availability of these biomarkers is still limited.

Therefore, one of the approaches of our group is to combine molecular and geochemical techniques in analogous modern marine systems. Without biomarker observations in paleoenvironments, we cannot predict how the current expansion of marine oxygen minimum and anoxic zones will affect -for example- the removal of bioavailable nitrogen, nor the feedback mechanisms that will take place within the carbon and nitrogen cycles in the presence of anthropogenic perturbations.