Thermo-Finnigan MAT253 Isotope Ratio Mass Spectrometer (IRMS), with a Kiel IV Carbonate Device, and on a Thermo-Finnigan Delta V Plus IRMS with Gasbench II (GB II) connected to a Conflo IV, both at the Analytical Laboratory for Paleoclimate Studies (ALPS) at the Jackson School of Geosciences, University of Texas at Austin. The precision of the Kiel IV/MAT253 IRMS for samples in this study is 0.05? for d18O and 0.03? for d13C (1s), as estimated via multiple analyses of a carbonate standard (n = 224), which is consistent with longterm precision for this instrument of 0.06? for d18O and 0.03? for d13C. The precision of the GB II/Delta V Plus IRMS is 0.07? for d18O and 0.03? for d13C (1s), as estimated via multiple analyses of the same carbonate standard (n = 25), which is consistent with long-term precision for this instrument of 0.07? for d18O and 0.03? for d13C. Replicate coral samples analyzed on both mass spectrometers yield similar results (mean difference = 0.03? for d18O and 0.12? for d13C; n = 35).

Yes, results are only reported to a depth of 200 cm as a result of diagenetic alteration at the bottom of the core, which is visible as dark patches in the Xradiographs and large excursions, as well as the lack of an annual cycle in the geochemical time series.

We develop and test a transfer function constructed using linear regression analysis of SBV coral d18Oanomaly variations and instrumental SSS over the period 1970?2007 CE [Thirumalai et al., 2011]. We performed a calibration-verification exercise (Figure 6) between d18Oanomaly and SSS at SBV to assess the robustness of the transfer function [Quinn and Sampson, 2002]. The slopes in equations (1)?(3) are within error of each other; however, the intercepts are slightly different. Despite this small difference, the similarity of the lines (Figure S2) provides confidence that the transfer function developed in this study can be used to reconstruct past changes in salinity at this locality based on coral d18O variations. We also note that there is a signal in the residuals, which likely reflects a small temperature component in the coral d18O anomaly signal (Figure 6, bottom), most likely due to the small changes in seasonality over this time period (Figure 4c).