Hydrogen isotope fractionation response to salinity and alkalinity in a calcifying strain of Emiliania huxleyi

Hydrogen isotope ratios of long-chain alkenones (δ2HC37) correlate with water isotope ratios and salinity, albeit with varying degrees of biological fractionation between alkenones and water. These differences in fractionation are the result of environmental and species related effects, which in some cases have consequences for the magnitude of the δ2HC37 response per unit increase in salinity. Earlier culture experiments have focused on constraining hydrogen isotope fractionation factor α in non-calcifying strains of Emiliania huxleyi. Here we studied isotopic fractionation in a calcifying strain of E. huxleyi and show that although absolute fractionation is different, the response to changes in salinity and alkalinity is similar to those of non-calcifying species. This suggests that calcification does not alter the δ2HC37 response to salinity significantly.