Extended Data Fig. 9: Different sea surface temperature proxies record varying reductions in the zonal sea surface temperature gradient, and a dissolution correction and different Mg/CaSW record is applied to this study’s data.
From: Pliocene decoupling of equatorial Pacific temperature and pH gradients
a, b, SST records from the eastern (blue) and western (red) equatorial Pacific. a, SST records which evince a collapse of the modern zonal SST gradient include: T. sacculifer Mg/Ca data1 calibrated and corrected for Mg/CaSW with the Bayesian BAYMAG calibration88 with 95% confidence intervals (pale blue and red bands); UK′37 data7,119 using a global ocean annual-mean calibration126 with its associated 1 s.e. (±1.1 °C) (dark blue and red bands, dashed line shows upper saturation limit of the proxy); T. sacculifer Mg/Ca data1 using a species-specific calibration125 and corrected for Mg/CaSW by O’Brien et al.11 (bright blue and red lines, no uncertainty reported); and O. universa Mg/Ca data (this study) using a species-specific calibration89 and the Mg/CaSW record of Fantle and DePaolo81, assuming a linear relationship between Mg/CaSW and Mg/Catest (square markers with calibration error in error bars). Note that the three Mg/Ca records in this panel all use different Mg/CaSW records11,81,88. As the goal of this figure is to depict the range of temperature (and temperature gradient) reconstructions from the literature, we have not standardized them all to the same Mg/CaSW record. b, SST records which evince the modern zonal SST gradient being roughly maintained back into the early Pliocene/late Miocene, derived from TEX86 data3 using the calibration of Kim et al.121, with its associated calibration error (±2.5 °C) (blue and red bands). c, SSTs calculated from O. universa Mg/Ca data in this study both with (solid squares) and without (empty squares) applying the dissolution correction of Regenberg and colleagues118. d, Western equatorial Pacific (WEP) SSTs according to T. sacculifer Mg/Ca data1 (lines) versus O. universa (this study, points). Depending on choice of Mg/CaSW record (light versus darker colours), even T. sacculifer may record cooler-than-modern temperatures in the WEP. Average annual modern WEP SST (from GLODAPv266) given in the dashed line.
