Extended Data Fig. 1: Depth-latitude distributions of seawater properties in the Atlantic Ocean.

a, Seawater Alk*, b, seawater age and c, potential density (σ0) are shown in depth-latitude diagrams separated according to three biogeochemically-distinct regions on which we base our analysis, corresponding to the (left) subtropical South Atlantic, (center) Equatorial Atlantic and (right) subtropical Noth Atlantic regions shown in Extended Data Fig. 2.