An improved boron isotope pH proxy calibration for the deep-sea coral Desmophyllum dianthus through sub-sampling of fibrous aragonite

摘要

The isotopic composition of boron (delta B-11) in marine carbonates is well established as a proxy for past ocean pH, however, its robust application to palaeo-environments relies on the generation of species-specific calibrations. Existing calibrations utilising the deep-sea coral (DSC) Desmophyllum dianthus highlight the potential application of this pervasive species to pH reconstructions of intermediate depth waters. Nevertheless, considerable uncertainty remains regarding the estimation of seawater pH from these bulk skeletal delta B-11 measurements, likely resulting from microstructural heterogeneities in delta B-11 of D. dianthus. To circumvent this problem, thus improving the reliability of the D. dianthus delta B-11-pH calibration, we present a new delta B-11 calibration of micro-sampled fibrous aragonite from this species.