A better understanding of the manner in which the ocean operates is essential to the preparation for the consequences of the generation of CO{sub 2} by fossil fuel burning. Examples are as follows: (1) the ocean will ultimately take up a major fraction of the CO{sub 2} produced, but this uptake is retarded by the slow mixing rates, in order to predict the uptake, researchers must develop and validate general circulation models for the ocean; (2) during glacial time large global climate changes occurred. The changes were abrupt happening in a few decades. The trigger for these changes appears to have been reorganizations of the large-scale thermohaline circulation of the ocean. Models suggest that if the CO{sub 2} content of the atmosphere rises to more than 700 ppm, then a possibility exists that another such reorganization might occur. Hence, researchers must learn more about the factors influencing deep-water formation both in the northern Atlantic and in the Souther Ocean. The thrust of this research was to develop constraints based on the distributions of chemicals and tracers in the sea. The accomplishments are outlined in this report.

The authors have completed the studies using the inorganic carbon cycle in the zonally averaged ocean circulation model to calculate anthropogenic uptake of CO{sub 2} and bomb radiocarbon. While the results are in broad agreement with previous studies, the authors have learned that horizontal mixing processes due to gyre circulation are important for transient tracer experiments over a few decades. Using the inorganic carbon cycle model the authors have started to look at the distributions of {delta}{sup 13}C in the ocean. The model is able to reproduce faithfully the air-sea fractionation of {delta}{sup 13}C. The effect of changing sea surface temperature in the middle and low latitudes of the world ocean on {rho}CO{sub 2}{sup atm} is studied in this model and compared to the organic carbon cycle model of the Hamburg group. They find significant differences in sensitivity and are in the process of investigating possible reasons. Incorporation of the organic component is still ongoing. In the present version the surface concentrations of phosphate are still too high indicating strong upwelling.