Figure F4. North-south cross section of water masses, characterized by dissolved oxygen concentrations in the southeast Pacific (Ocean Climate Laboratory, 1999). Southward-spreading mid-depth waters (PCW = Pacific Central Water) are characterized by relatively low oxygen and salinity and high nutrients. Northward-spreading Antarctic Intermediate Water (AAIW), above 1 km depth, is high in oxygen but is low in both salinity and nutrients. The Gunther Undercurrent (GUC) flows southward between 100 and 400 m water depth and is characterized by relatively low oxygen, high nutrients, and high salinity. Vertical bars indicate the water depth range of Sites 1233, 1234, and 1235 relative to the last glacial sea level lowering of ~130 m.

Figure F4. North-south cross section of water masses, characterized by dissolved oxygen concentrations in the southeast Pacific (Ocean Climate Laboratory, 1999). Southward-spreading mid-depth waters (PCW = Pacific Central Water) are characterized by relatively low oxygen and salinity and high nutrients. Northward-spreading Antarctic Intermediate Water (AAIW), above 1 km depth, is high in oxygen but is low in both salinity and nutrients. The Gunther Undercurrent (GUC) flows southward between 100 and 400 m water depth and is characterized by relatively low oxygen, high nutrients, and high salinity. Vertical bars indicate the water depth range of Sites 1233, 1234, and 1235 relative to the last glacial sea level lowering of ~130 m.