Calibration and application of B/Ca, Cd/Ca, and dB in Neogloboquadrina pachyderma (sinistral) to constrain CO2 uptake in the subpolar North Atlantic during the last deglaciation

[1] The North Atlantic and Norwegian Sea are prominent sinks of atmospheric CO2 today, but their roles in the past remain poorly constrained. In this study, we attempt to use B/Ca and dB ratios in the planktonic foraminifera Neogloboquadrina pachyderma (sinistral variety) to reconstruct subsurface water pH and pCO2 changes in the polar North Atlantic during the last deglaciation. Comparison of core-top results with nearby hydrographic data shows that B/Ca in N. pachyderma (s) is mainly controlled by seawater B(OH)4 /HCO3 with a roughly constant partition coefficient KD 1⁄4 B=Ca 1⁄2 CaCO3 B OH ð Þ 4 =HCO 3 1⁄2 seawater of