Fig.2. Density structure of oceans as function of climate.

Values in Atmosphere E = evaporation; P = precipitation;
Values in Ocean High prod = high primary productivity; Lo w prod = low primary productivity.
Shaded areas are zones of potential anoxicity based in part by analogy with the modern North Pacific (see Reid, 1965, p. 52).

Case A (non-glacial). High-latitude water (HLWa) temperature greater than 5°C. Deep water formed at mid-latitudes. No water mass formation from freezing of sea ice (after Wilde and Berry, 1982, p. 214).

Case B (pre-postglacial). High-latitude water (HLWb) temperature less than 5°C but greater than freezing point. Deep water formed at high latitudes. No significant water mass formation from freezing of sea ice (after Wilde and Berry, 1982, p. 216).

Case C (glacial) (modern Pacific Ocean). Major water mass formation at high latitudes from freezing of sea ice (after Monin et al. 1977, p. 38).