Extended Data Fig. 5: Meridional Pacific Ocean [CO32-] distribution.
From: Last glacial atmospheric CO2 decline due to widespread Pacific deep-water expansion
a, [CO32-] transect. b, hydrographic sites11 used to generate a. Today, the core of PDW is located at ~1–2 km in the polar North Pacific with a [CO32-] of ~50 μmol/kg. The low [CO32-] signature can be traced in the Southern Ocean (~50°S) due to the southward transport (southward black arrows) of PDW at ~1–2 km33. During the LGM, the core of GPDW is thought to deepen to ~3 km (dashed half circle)34. Our study suggests that the southward transport (dashed arrows) of GPDW was more extensive. By the time when GPDW was transported to the Pacific sector of the Southern Ocean, its signals would be transported via ACC (circle with an inner dot; transport out of the page) to the South Atlantic Ocean. White circles indicate cores at 3–4 km from the equatorial Pacific Ocean shown in Fig. 3. These cores show lower [CO32-] than the abyssal South Atlantic waters (TNO57–21), indicating that GPDW likely had lower [CO32-] than GAABW.
