Postdoc position: Mortality and virus-host interactions of phytoplankton in Arctic winters under warming

The Department of Marine Microbiology and Biogeochemistry (MMB) of NIOZ is looking for a talented and dedicated Postdoctoral scientist to join our research on marine virus ecology. You will be part of the larger research consortium project SURPHYVE, aimed at investigating the survival of phytoplankton in Arctic winters under warming.

THE INSTITUTE

NWO-NIOZ Royal Netherlands Institute for Sea Research is the Dutch national oceanographic institute and principally performs academically excellent multidisciplinary, fundamental, and frontier applied marine research addressing important scientific and societal questions pertinent to the functioning of the ocean and seas. NIOZ includes the National Marine Research Facilities (NMF) department that operates a fleet of research vessels and the national pool of large seagoing equipment, and supports excellence in multidisciplinary marine research, education, and policy development.

The research of the Department of Marine Microbiology and Biogeochemistry (MMB) has a long history of studying all domains of microbial life (viral, prokaryotic and eukaryotic), their interactions, and their role in biogeochemical cycling in a variety of marine environments, varying from coastal environments to the deep ocean and sediments. The department is equipped with state-of-the-art laboratories, bioinformatics resources and analytical equipment, and has an excellent level of technical support.

THE PROJECT

General background SURPHYVE.  In the Arctic Ocean, photosynthetic phytoplankton face a major energetic bottleneck during winter: they must survive several months of darkness during the polar night. To survive, polar phytoplankton species may rely on storage compounds accompanied by downregulation of respiration and/or switch to mixotrophy (heterotrophic utilization of organic compounds or microbial prey). The fast rate of climate warming in the Arctic is expected to further challenge phytoplankton winter survival, as the higher metabolic rates at higher temperatures might deplete energy reserves faster (causing a stronger dependence on heterotrophic carbon acquisition). Additionally, mortality rates (grazing, sinking, and viral lysis) can be expected to change with warming. The mechanisms underlying Arctic phytoplankton winter survival are, however, not well understood. Using a complementary approach - combining the analysis of existing winter omics data, targeted winter field work, and detailed experiments for rate estimations and process-understanding - SURPHYVE will provide the basis for urgently needed projections on how (future) changes in winter phytoplankton communities affect seeding the spring bloom, and consequently the structure and production of the pelagic Arctic ecosystem.

The SURPHYVE project is a collaboration between the University of Amsterdam (UvA, Dr. Susanne Wilken), the Alfred Wegener Institute (AWI, Dr. Clara Hoppe), and the Royal Netherlands Institute of Sea Research (NIOZ, Prof. Corina Brussaard), assessing the mechanisms underlying Arctic phytoplankton winter survival under current and warming conditions. A PhD (UvA) investigates the role of phagotrophy in phytoplankton winter survival, PD-1 (AWI) will focus on osmotrophy as survival mechanism, and PD-2 (NIOZ) will focus on the potential of virovory, phytoplankton mortality and virus-host interactions. The current vacancy regards the 33-months Postdoc position PD-2 with NIOZ, aimed to start preferably summer 2026.

Postdoc research. The research related to this PD position (33 months) is diverse and involves winter fieldwork, laboratory experiments and analysis of omics data sets. The research will focus on (1) omics analysis to identify and investigate the prevalence of Arctic phytoplankton viruses in combination with their host abundance dynamics by exploiting an existing omics data set; and by sorting field samples for meta-genomics analysis, (2) fieldwork (2x 1 month) to determine phytoplankton mortality rates (viral lysis, grazing and sinking) during the polar night as these remain poorly understood and have not been measured thus far; and determine viral lysis rates of prokaryotes to assess the importance as source of dissolved organic matter (for osmotrophic Arctic phytoplankton), (3) Lab experiments to explore virovory potential by different key Arctic phytoplankton as additional mechanism to survive the winter; investigate virus-host interactions under warming using Micromonas and their viruses; and explore sinking rates of the mixotrophic phytoplankton determined by the other partners in the project.

This PD position is tightly linked to the other positions within the SURPHYVE project. The fieldwork and some of the experiments will be performed as a team. Depending on your interest, there can be collaboration with Dr. Guy Schleyer (NIOZ) on cellular lipidomics.

THE CANDIDATE

• PhD in relevant discipline

• The perfect candidate* has thorough scientific expertise in marine phytoplankton and viral ecology, and microbial meta-omics techniques

• Ideally*, you have comprehensive experience with (Arctic) fieldwork, viral lysis rate measurements, flow cytometry & cell sorting, meta-genomics, meta-transcriptomics and bioinformatics, and proficient knowledge of functional ecology of phytoplankton, mixotrophy, and food web dynamics

• A demonstrated ability to work with programming software (e.g., R, Phyton, Matlab)

• Strong practical skills with the ability to work organized, accurately and adaptively

• Highly self-motivated, able to work both independently and as part of a team

• Excellent cognitive and communication (in English) skills both written in peer-reviewed literature and orally through presentations at meetings and conferences

*We understand that candidates may not meet all these criteria from the start.

We want to be a transparent institute with a healthy working climate and an inclusive culture, where people from diverse backgrounds and genders bring their talents and further develop these talents. We aim for inclusive decision-making processes and expect our leadership to show visible commitment, awareness of bias, and cultural intelligence.

CONDITIONS

• Employment of this full-time position (40-hour week) at Royal NIOZ is by NWO-I for a duration of 33 months.

• Salary compliant with CAO-WVOI (Collective Labour Agreement for Dutch Research Institutes) scale 10 or 11 depending on relevant experience.

• The freedom to fulfill your role and space and opportunities for your personal (talent) development with the help of the NIOZ Academy.

• 338 annualized holiday hours for a full-time 40-hour work week.

• Pension scheme via ABP, 8% holiday allowance and a year-end bonus of 8.33%.

• 2nd class public transportation travel is reimbursed 100%.

• Employment benefits plan to exchange a portion of your salary for days off or vice versa or can be used to purchase a bicycle with tax benefits.

• We offer relocation expenses for employees coming from abroad and support with finding accommodation.

MORE INFORMATION

The fieldwork will take place November 2026 and January 2027, therefore we aim for the starting date of this PD-position to be summer 2026.

Deadline for submission is 15 February 2026, midnight CET

Please note, we aim to have a short online interview on 18 March 2026 and an in-person interview at NIOZ-Texel location on 25 March or 1 April 2026.

For additional information about this vacancy, please contact Prof Dr. Corina Brussaard. For additional information about the procedure, please send an e-mail to working@nioz.nl