Sea Surface Temperature and Salinity Reconstruction from Geochemical Tracers of a Massive Coral in the Persian Gulf

The δ18O, δ13C, and strontium/calcium (Sr/Ca)-record was measured from a 7-year old Platygyra sinensis coral located offshore Larak Island in the Persian Gulf at a resolution of 22 samples/year. An increased sampling resolution of 55 samples/year over two annual cycles was also compared with the 22 sample resolution to evaluate the effectiveness of the sampling procedure. The resulting data exhibited identical results between the two methods. By means of previously reported equations, Sr/Ca derived sea surface temperatures (SST) ranged between 17 to 30 °C, with an average of 24.7 °C. The inter annual variability in the Platygyra sinensis indicated a significant correlation with COADS data. In addition, the relation between the δ18O in Platygyra sinensis coral and the Sr/Ca-estimated SST data was assessed. Subtracting the Sr/Ca-based SST values from the δ18O of the coral, the δ18O of water was calculated. These data were then used to construct ranges of sea surface salinity (SSS) in the region.