Shifts in zooplankton traits and community composition in the North Sea

Zooplankton plays a key role in the marine food web and represents the trophic link between the primary producers (phytoplankton) and higher trophic levels. Yet, information is still missing on how variation at the phytoplankton level and in abiotic variables will affect zooplankton traits (e.g., stoichiometry and stable isotope composition) and community composition. Stable isotope analyses of nitrogen (N) and carbon (C) have been used extensively to study marine food webs with the δ¹⁵N of organic matter being an indicator of the trophic position of consumers in a food chain, while the δ¹³C of organic matter provides insights into the food source assimilated by a consumer. Changes in primary production and the biochemical composition of phytoplankton are likely to influence the zooplankton community, as they affect the quantity and quality of food available to various zooplankton taxa. Focusing on the Dutch North Sea, this project aims to investigate whether the zooplankton community and the composition of stable isotopes change spatially and over the course of a day, and how this relates to their food source, phytoplankton. 

You will examine samples of phytoplankton and zooplankton for stable isotope composition collected June 2025. These data are complemented by information on the composition of the zooplankton community.

Requirements

The student will be based at NIOZ on Texel for the duration of the project, which is expected to be ~6 months with a flexible starting date from January 2026. This project includes a laboratory component for analyzing stable isotopes and a data processing component following the analysis. There are also possibilities, depending on the starting date, to join short research cruises (4-5 days) for additional sample collection.

Contact

If you are interested in the project, please contact Hanna Stegeman (hanna.stegeman@nioz.nl).