Abstract
Sr/Ca ratios recorded in the aragonite skeleton of massive coral colonies are commonly used to reconstruct seasonal‐ to centennial‐scale variability in sea surface temperature (SST). While the Sr/Ca paleothermometer is robust in individual colonies, Sr/Ca‐SST relationships between colonies vary, leading to questions regarding the utility of the proxy. We present biweekly‐resolution calibrations of Sr/Ca from five Porites spp. corals to satellite SST across 10° of latitude in the Red Sea to evaluate the Sr/Ca proxy across both spatial and temporal scales. SST is significantly correlated with coral Sr/Ca at each site, accounting for 69–84% of Sr/Ca variability (P ≪ 0.01). Intercolony variability in Sr/Ca‐SST sensitivities reveals a latitudinal trend, where calibration slopes become shallower with increasing mean annual temperature. Mean annual temperature is strongly correlated with the biweekly‐resolution calibration slopes across five Red Sea sites (r2 = 0.88, P = 0.05), while also correlating significantly to Sr/Ca‐SST slopes for 33 Porites corals from across the entire Indo‐Pacific region (r2 = 0.26, P < 0.01).="" although="" interannual="" summer,="" winter,="" and="" mean="" annual="" calibrations="" for="" individual="" red="" sea="" colonies="" are="" inconsistently="" robust,="" combined="" multicoral="" calibrations="" are="" significant="" at="" summer="" (r2="0.53," p="" ≪="" 0.01),="" winter="" (r2="0.62," p="" ≪="" 0.01),="" and="" mean="" annual="" time="" scales="" (r2="0.79," p="" ≪="" 0.01).="" our="" multicoral,="" multisite="" study="" indicates="" that="" the="" sr/ca="" paleothermometer="" is="" accurate="" across="" both="" temporal="" and="" spatial="" scales="" in="" the="" red="" sea="" and="" also="" potentially="" explains="" for="" the="" first="" time="" variability="" in="" sr/ca‐sst="" calibration="" slopes="" across="" the="" indo‐pacific="" region.="" our="" study="" provides="" strong="" evidence="" supporting="" the="" robustness="" of="" the="" coral="" sr/ca="" proxy="" for="" examining="" seasonal="" to="" multicentury="" variability="" in="" global="" climate="">