Coccolithophore calcite production from nannofossil records

The production, export and accumulation of calcite (CaCO₃) are key components of the marine carbon system and the global carbon cycle. Coccolithophores are responsible for ~20-80% of the open ocean CaCO₃ production. Over geological timescales, their activity significantly influences the global carbon cycle, impacting long-term climate evolution. Despite the critical importance of this group, an integrated understanding of the environmental factors that control their CaCO₃ production remains incomplete. This uncertainty arises from difficulties extrapolating laboratory-based findings to natural settings and challenges interpreting fossil records. We present new profiles of the distribution of key coccolithophore species and groups in the modern Atlantic Ocean alongside detailed morphometric analyses at the individual coccolith level. Applying a suite of advanced micropaleontological and morphometric techniques on well-preserved surface sediment materials, we explore different pathways for reconstructing coccolithophore physiology and CaCO₃ production from nannofossil records. This research provides new insights into the dominant environmental controls over coccolithophore CaCO₃ production in response to natural oceanic forcing. Relationships between coccolithophore assemblage structure, group-specific physiology, morphometric variability and CaCO₃ production with the environment contribute to the understanding of the role of coccolithophores in the marine carbon cycle and provide a basis for a novel application of nannofossil assemblages for the reconstruction of past oceanic physicochemical conditions.