Empirical assessment of coral Sr/Ca and Mg/Ca ratios as climate proxies using colonies grown at different temperatures

摘要

Coral strontium/calcium (Sr/Ca) and magnesium/ calcium (Mg/Ca) ratios might be useful for reconstructing past sea surface temperature (SST) in tropical oceans where instrumental data are limited. However, the link between coral skeletal trace elements and SST is disputed, and biological factors such as skeletal growth rate may also affect trace elements in a coral. We studied the relationships between growth rate and SST and Sr/Ca and Mg/Ca ratios using corals (Porites spp.) cultured in thermostated tanks. Sr/Ca was controlled primarily by SST, while Mg/Ca mainly reflected the growth rate with negligible contribution from species on both the variations. These relationships are consistent with modeled results of cation partitioning during aragonite crystal formation.