Fig. 1

Locations of cores discussed in this paper. Blue plus: KNR176-GGC17/JPC30 from this study (5.02°N, 77.63°W, 707 m); Dots: intermediate-depth cores MV99-MC19/GC31/PC08 off Baja California (705 m, cyan)^13,32, VM21-30 near the Galapagos (617 m, magenta)¹⁴, SO161-SL22 off the Chilean Margin (1000 m, yellow)¹⁵ and EW0408-85JC in the Gulf of Alaska (682 m, dark cyan)³⁸; Squares: mid-depth cores in the EEP (TR163-23, 2730 m, magenta⁴; ODP1240, 2920 m, cyan⁵) and in the WEP (MD98-2181, 2100 m, dark cyan¹; MD01-2386, 2800 m, yellow⁸); Diamonds: sites of an EEP oceanic ΔpCO₂ record (ODP1238, orange)¹⁰ and of a plankton tow study in the Panama Basin (dark green)²⁴. The sites are plotted with a background of the pre-bomb ¹⁴C reservoir age at 40 m (the median depth of the EEP thermocline²¹ and also the calcification range of N. dutertrei as determined from the plankton tow study²⁴) from the gridded GLODAP data product²³. EUC is shown schematically with the black dashed lines with arrow²². The symbol colors used in Fig. 3 follows those in this figure. Figure made with Ocean Data View⁵⁹