Equatorial Pacific seawater pCO₂ variability since the last glacial period

The ocean may have played a central role in the atmospheric pCO₂ rise during the last deglaciation. However, evidence on where carbon was exchanged between the ocean and the atmosphere in this period is still lacking, hampering our understanding of global carbon cycle on glacial-interglacial timescales. Here we report a new surface seawater pCO₂ reconstruction for the western equatorial Pacific Ocean based on boron isotope analysis-a seawater pCO₂ proxy-using two species of near-surface dwelling foraminifera from the same marine sediment core. The results indicate that the region remained a modest CO₂ sink throughout the last deglaciation.