Unresolved issues on the timing and magnitude of changes in deep ocean chemical composition and circulation can be tackled with selective paired measurements of benthic foraminiferal Cd, &13C, and &180 in deep ocean sediment cores. Gaps will be filled and benthic paleochemical coverage of the last glacial maximum, and cores from the South Atlantic, Antarctic, and Northwest Pacific will be examined to clarify why existing &13C and Cd evidence suggest such different glacial paleochemical characteristics. Two more long downcore Cd records will be completed to constrain the amplitude, timing, and spectral characteristic of benthic paleochemical changes. This data will be examined from the perspective of simple models for carbon and nutrient cycling within the ocean, in order to assess the role of ocean chemistry and circulation in controlling atmospheric CO2.
