Distinct responses of planktonic foraminiferal B/Ca to dissolution on seafloor

We have measured B/Ca in four core‐top planktonic foraminiferal species ( Globigerinoides ruber (white), Globigerinoides sacculifer (without final sac‐like chamber), Neogloboquadrina dutertrei , and Pulleniatina obliquiloculata ) from three depth transects (the Caribbean Sea, the southwestern Indian Ocean, and the Ontong Java Plateau) to evaluate the effect of dissolution on planktonic foraminiferal B/Ca. At each transect, G. ruber (w) and G. sacculifer (w/o sac) show decreasing B/Ca with increasing water depth. This decrease in B/Ca is accompanied with decreases in shell weights, Mg/Ca, and bottom water calcite saturation state. This indicates a postdepositional dissolution effect on B/Ca in these two species. The strong correlation observed between changes in B/Ca and bottom water calcite saturation state offers an approach to correcting for the dissolution bias. By contrast, B/Ca in N. dutertrei and P. obliquiloculata remains unchanged along depth transects, although shell weights and Mg/Ca display significant declines. Overall, our core‐top results suggest species‐specific dissolution effects on B/Ca in different planktonic foraminiferal species.