Temperature Induced Physiological Reaction Norms of the Coccolithophore Gephyrocapsa oceanica and Resulting Coccolith Sr/Ca and Mg/Ca Ratios

Coccolithophores are one of the major contributors to pelagic production calcium carbonate and their fossilized remains a key component biogeochemical cycles (Ca), magnesium (Mg), other divalent cations present in intracellular precipitated calcitic structures (coccoliths). The geochemical signature coccoliths (e.g., Sr/Ca Mg/Ca ratios) is used as paleoproxy reconstruct past environmental conditions understand underlying physiological precipitation kinetics. Here, we elemental fractionation Sr Mg calcite coccolithophore Gephyrocapsa oceanica from controlled laboratory experiments applying an extended temperature gradient (12 27°C). reaction norm G. , terms growth rate, exhibited optimum behavior while partition coefficient (D ) was linearly correlated with D indicated no specific trend. Our results indicate: (1) presumably secondary control (2) importance calibrating coccolithophore-based proxies using that include full norms (i.e., possible non-linear response) drivers temperature, salinity, pH, etc.). presented contribute improved understanding kinetics involved regulating coccolith give additional implications for designing future calibrate apply based paleoproxies on fossil sediment record.