The oxygen content of longitudinal sections (from south to north) of the (A) Pacific and (B) Atlantic Oceans (Note that this graph exaggerates vertical proportions, especially the seafloor topography, in black). The scale for both is shown in (A) and is in units of micromoles of oxygen per kilogram of seawater. It can clearly be seen how the Pacific has older, nutrient-rich, oxygen-poor deep water while the Atlantic contains younger, nutrient-poor, oxygen-rich deep water.