Although the Southern Ocean plays an important role in the global carbon cycle and in the sequestration of industrial CO2 in the oceans, our understanding has been incomplete and sometimes contradictory due mainly to the paucity of observations. Therefore, an improved understanding of the biological, chemical and physical processes governing the distribution of CO2 in these waters is important for gaining knowledge of the carbon-nutrient cycle in the global oceans and for predicting the future trend of atmospheric CO2 and the Earth's climate.

A major controlling factor on the pCO2 of ocean water is temperature. An accurate knowledge of the temperature dependence of pCO2 in seawater is crucial for carbon cycle studies. Thus, direct measurements of pCO2 versus temperature have been made over a range of seawater chemistries and a functional relationship independent of any dissociation constants was established. The effect of temperature on the pCO2 is dependent on the TCO2 /Alkalinity ratio (hence of pH) with the temperature dependence greater at lower temperatures and a lower TC/Alk ratio. The results were also compared to the temperature dependence for various sets of dissociation constants.

Seasonal CO2 and nutrient data across the Polar Frontal Zone of the Pacific sector of the Southern Ocean were studied with an emphasis on estimating nutrient utilization ratios, new production and export. The annual mean rate of new production determined is consistent with the notion of the Southern Ocean as a low productivity area yet export was relatively high. Wintertime vertical stability of the upper water column, summer mixed layer depths and circulation patterns all affected the rates of new production. C/N/P ratios were observed to vary from the traditional Redfield values of 106/16/1 as a function of both the dominant biological process and phytoplankton assemblage. The departures from the "Redfield ratio" arise enhanced phosphate uptake by diatoms and preferential remineralization of phosphate. Silica/(C, N, and P) ratios also are highly variable both spatially and temporally.