Dataset for "Shallower living depth instead of higher seawater alkalinity enhanced calcification in bloom-forming coccolithophores during their Pleistocene acme event"

Coccolithophores are a group of algae living in the ocean contributing about 50% of carbonate production of the surface ocean. The occurrence of coccolithophores in the ocean has kept increasing the last decades due to global climate change. However, the detailed mechanism and carbon cycle effect of increased coccolithophore productivity are still unclear. In the Earth history, there have been several coccolithophore high-abundance events, providing an excellent analog of the modern and ongoing flourishing of coccolithophores. In this study, we provide investigations of the most recent coccolithophore high-abundance event that happened ~500-300 thousand years ago. We find that the enhanced global calcification cannot be fully explained by the variations of seawater alkalinity. Based on evidences of coccolithophore-derived carbon and oxygen isotope ratios, we suggest that more coccolithophore-available nutrient and shallower living depth are the key factor increasing coccolithophore productive. This finding could help ocean models to better constrain the ocean carbon cycles and predict the future climate changes.