The Red Sea is a semi-enclosed marginal sea with thermohaline deep water circulation that shows great sensitivity to climate systems in the North Atlantic region and around the world. Our understanding of the processes that affect surface water conditions and their links to deep water production in the Red Sea is not fully complete. In this study, we focused on a Porites lobata/lutea coral core from the northern Red Sea (Popponesset Reef; 25.58 ̊N, 36.55 ̊E). This coral core spans around 267 years, providing monthly resolution from 2010 to ~1743 CE. The coral core was analyzed for strontium-calcium (Sr/Ca) ratios, a known proxy for sea surface temperature (SST), allowing us to extend past the ~50 years of satellite SST data that have been collected. The Sr/Ca record shows distinct low frequency (multi-decadal) variability in both summer and winter seasons that is likely tied to influences from the North Atlantic, including the North Atlantic Oscillation (NAO) and Atlantic Multidecadal Oscillation (AMO). Oxygen isotopes (δ18O), proxies for SST and seawater salinity (and therefore density), were also measured, targeting the seasonal summer and winter extremes based on the Sr/Ca record. The δ18O and Sr/Ca records are very strongly correlated at monthly timescales due to the dominance of SST in driving both proxies at this site. However, the δ18O record diverges from Sr/Ca on decadal-multidecadal timescales, indicating low frequency variability in surface salinity as well. In the future, these coral records will be compared to records from three other coral cores spanning the north-central Red Sea to gain a better understanding of variability in Red Sea surface conditions and its influence on the processes of deep water circulation.
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