Coastal seas come alive at night with flashes of blue light produced by bioluminescent plankton, tiny organisms that form the basis of the marine food web. Yet despite their visibility, we still know surprisingly little about why and when these organisms light up, how environmental change affects them, and how their bioluminescence influences the wider marine ecosystem. This PhD project investigates these questions using a unique combination of long-term datasets, laboratory experiments, mesocosm studies, and ecosystem modelling. The research begins by analysing decades of plankton and environmental data from the North Sea to determine how factors such as temperature, salinity, nutrients, and species traits shape the distribution and dynamics of bioluminescent plankton. Next, I can use these factors in controlled laboratory experiments, which will test how environmental stressors influence light production, growth, and toxin production of a few key bioluminescent species. Large outdoor mesocosm experiments will bring the research to an ecosystem scale, and reveal how glowing and potentially toxic species affect bloom development, grazing pressure, and nutrient cycling. Finally, the project integrates all findings into a trait-based ecological model that predicts how bioluminescent blooms may evolve under future climate and environmental conditions. The findings will help scientists, monitoring agencies, and coastal observers better interpret when and why bioluminescent blooms occur, and what they mean for the health of our seas.

Linked team members: Mandy Velthuis; Marjolijn Christianen: