Characteristics of the deep ocean carbon system during the past 150,000 years: Sigma CO2 distributions, deep water flow patterns, and abrupt climate change

Studies of carbon isotopes and cadmium in bottom-dwelling foraminifera from ocean sediment cores have advanced our knowledge of ocean chemical distributions during the late Pleistocene. Last Glacial Maximum data are consistent with a persistent high-Sigma CO2 state for eastern Pacific deep water, Both tracers indicate that the mid-depth North and tropical Atlantic Ocean almost always has lower Sigma CO2 levels than those in the Pacific, Upper waters of the Last Glacial Maximum Atlantic are mure Sigma CO2-depleted and deep waters are Sigma CO2-enriched compared with the waters of the present, In the northern Indian Ocean, delta(13)C and Cd data are consistent with upper water Sigma CO2 depletion relative to the present, There is no evident proximate source of this Sigma CO2-depleted water, so I suggest that Sigma CO2-depleted North Atlantic intermediate/deep water turns northward around the southern tip of Africa and moves toward the equator as a western boundary current, At long periods (>15,000 years), Milankovitch cycle variability is evident in paleochemical time series, But rapid millennial-scale variability can be seen in cores from high accumulation. rate series, Atlantic deep water chemical properties are seen to change in as little as a few hundred gears or less, An extraordinary new 52.7-m-long core from the Bermuda Rise contains a faithful record of climate variability with century-scale resolution, Sediment composition can be linked in detail with the isotope stage 3 interstadials recorded in Greenland ice cores, This new record shows at least 12 major climate fluctuations within marine isotope stage 5 (about 70,000-130,000 gears before the present).