Global drivers of eukaryotic plankton biogeography in the sunlit ocean

Eukaryotic plankton are a core component of marine ecosystems with exceptional taxonomic and ecological diversity, yet how their ecology interacts with the environment to drive global distribution patterns is poorly understood. In this work, we use Tara Oceans metabarcoding data, which cover all major ocean basins, combined with a probabilistic model of taxon co-occurrence to compare the biogeography of 70 major groups of eukaryotic plankton. We uncover two main axes of biogeographic variation. First, more-diverse groups display clearer biogeographic patterns. Second, large-bodied consumers are structured by oceanic basins, mostly through the main current systems, whereas small-bodied phototrophs are structured by latitude and follow local environmental conditions. Our study highlights notable differences in biogeographies across plankton groups and investigates their determinants at the global scale.