This study projects a global increase in plankton species richness by the end of the century, driven by ocean warming and a poleward shift of species distributions. However, the responses differ between phytoplankton and zooplankton, with zooplankton richness declining in the tropics and increasing strongly in temperate and subpolar latitudes, leading to significant species turnover and potential disruption of ecosystem services.

The authors declare no competing interests. The study received funding from various sources, including the European Union's Horizon 2020 research and innovation program, but this funding is not considered a conflict of interest.

This study uses a comprehensive ensemble modeling approach to project future changes in marine plankton diversity, addressing key limitations of previous studies. The large number of species considered, the use of multiple SDMs and ESMs, and the focus on functional groups provide valuable insights into the potential impacts of climate change on marine ecosystems. While the study has some limitations related to niche conservatism assumptions, the reliance on presence-only data, and the limited number of environmental predictors, the ensemble approach and the detailed analysis of uncertainties strengthen the overall robustness of the findings.