Fig. 2: Evolution of FB-δ15N and climate over the Cenozoic.
From: Enhanced ocean oxygenation during Cenozoic warm periods
a, Compilation of new and previously published SST data based on the TEX86 palaeothermometer, divided into high latitudes (above 50° N/S) and low/middle latitudes (0–40° N/S), with LOESS smoothing (factor 0.02) and 90% confidence interval (see Methods and Supplementary Data 2). TEX86 temperature estimates are based on the BAYSPAR calibration (see Methods). The grey line shows the benthic foraminiferal oxygen isotope ratio (δ18O) compilation by Westerhold et al.8. b, Δδ15NP-A is the FB-δ15N difference between Pacific ODP Site 872 and Atlantic DSDP Site 516 (black line) or between Pacific ODP Site 1209 and Atlantic ODP Site 1263 (grey line). ΔSSTL-H (red line) is the SST difference between low/middle latitudes and high latitudes (from a; the propagated 90% confidence interval for ΔSSTL-H is shown in Extended Data Fig. 4b). c, Average of species-specific FB-δ15N from ODP Site 872 (green) and DSDP Site 516 (blue), together with mixed-taxa FB-δ15N from ODP Site 1209 (light green) and ODP Site 1263 (light blue), calculated as the average of the two size fractions18. Triangles and circles of different colours indicate individual species-specific or genus-specific FB-δ15N in Site 872/1209 and Site 516/1263, respectively (see Extended Data Fig. 1 for details). Light pink bars indicate the first signs of global warming into the EECO and the MMCO, and darker bars indicate the main warm intervals, based on the benthic foraminifer δ18O (a). Ple, Pleistocene; Pli, Pliocene; Pal, Palaeocene.
