Multifaceted Contributions of Coccolithophores to Ocean Carbon Export

Abstract

Coccolithophores, a type of unicellular calcifying algae, are widely distributed across the global ocean. They contribute to the ocean carbon cycle by producing organic and inorganic carbon. Hence, they function as multifaceted contributors to oceanic carbon pumps, the biological carbon pump (BCP) and the carbonate counter pump (CCP). Global climate change profoundly impacts ocean environments, leading to ocean acidification, increased sea surface temperature, and nutrient depletion, all of which influence the physiology of coccolithophores. The accumulation and subsequent sinking of carbon produced by coccolithophores contribute to the total carbon export in the water column. This article reviews the physiology and distribution of coccolithophores, expounds on the intricate contribution of coccolithophores to BCP and CCP separately, and summarizes how climate-induced alterations in environmental factors (e.g., temperature, nutrient supply, light, and carbonate chemistry) affect the carbon accumulation and sinking rate of coccolithophores on the basis of culture experiments and field investigations. This study provides a foundation for assessing the contribution of coccolithophores to carbon export under potential future global warming scenarios.