Planktonic calcifying organisms regulate ocean carbonate chemistry and atmospheric CO2. This study quantifies pelagic calcium carbonate (CaCO3) production in the North Pacific, revealing that coccolithophores dominate (~90% of total CaCO3 production), with pteropods and foraminifera playing secondary roles. Pelagic CaCO3 production exceeds sinking flux at 150 and 200 m, indicating significant remineralization within the photic zone. This shallow dissolution explains discrepancies between previous production estimates. Future CaCO3 cycle changes and their impact on atmospheric CO2 will depend on how these remineralization processes respond to anthropogenic warming and acidification.

Patrizia Ziveri, William Robert Gray, Griselda Anglada-Ortiz, Clara Manno, Michael Grelaud, Alessandro Incarbona, James William Buchanan Rae, Adam V. Subhas, Sven Pallacks, Angelicque White, Jess F. Adkins, William Berelson