2025/09/16 by Joost de Vries, Fanny Monteiro, Alex J. Poulton +2 · 1 voice
Environmental Science · Earth and Planetary Sciences · #Marine Bivalve and Aquaculture Studies #Paleontology and Stratigraphy of Fossils #Coral and Marine Ecosystems Studies
paper · pdf · doi:10.1101/2025.09.11.675535
Abstract Coccolithophores are diverse calcifying plankton, yet most research has focused on a single species, Gephyrocapsa huxleyi , with the global contributions of other species hitherto unexplored. Since coccolithophores account for the majority of marine calcium carbonate (CaCO 3 ) production, this narrow focus risks biasing our understanding of CaCO 3 cycling, as other species differ in their distributions, CaCO 3 production and response to climate change. Using a global, species-resolved machine-learning approach, we show that G. huxleyi contributes only about 7% of estimated coccolithophore CaCO 3 stock, while a morphologically and functionally diverse assemblage dominates. Since stock contributions are a good proxy for contribution to production, our findings challenge the view that G. huxleyi underpins CaCO 3 cycling and show that lab and in situ datasets centred on this species capture only a small fraction of coccolithophore calcification. Our work identifies key species and regions to guide future laboratory, in situ, and modelling efforts, laying the groundwork for more realistic representations of CaCO 3 cycling under climate change.