Background Information

The concern over rising atmospheric CO₂levels due to human activities and the proposed CO₂-induced global warming has amplified the need to better understand the role of the ocean in the carbon cycle. The oceans are believed to act as a sink for human-induced, or "excess", CO₂. Most of our knowledge of the distribution of excess CO₂ in the oceans has come indirectly from the study of proxy data, namely the two major transient tracers, tritium and ¹⁴ C (Fine et al., 1981 and 1983; Stuiver and Oslund, 1980; Ostlund and Stuiver, 1980; and Stuiver and Ostlund, 1983). Other studies have attempted to quantify the oceanic penetration of excess CO₂ by using carbonate data directly (Chen 1982a,b; Chen, 1984; Chen et al., 1985; Chen et al., 1986; and Takashi et al., 1980).

The deep waters of the North Pacific Ocean are considered to be the oldest of the world's oceans. Extensive oceanographic investigation has been conducted in the North Pacific Ocean (BenYaakov, 1927; Berger et al., 1976; Broecker et al., 1982; Chen and Pytkowicz, 1979; Chen et al., 1986; Cline et al., 1985; Feely et al., 1982 and 1986; Gordon, 1973; Knauer et al., 1979; Kroopnick et al., 1970; Reid, 1973a,b; Roden, 1972, 1977, and 1979; and Rodman and Chen, 1978). These studies, especially in physical oceanography, have provided an excellent foundation for other types of study, including studies of the CO₂-carbonate system. The carbonate data provided in this package are the result of samples collected during three cruises in the North Pacific Ocean. These data, along with data from other expeditions, provide an excellent overall picture of the carbonate chemistry system in the North Pacific Ocean.