摘要：The North Pacific is considered a ter-minal region of the "Ocean's Conveyer belt circulation". Abyssal waters from the south flow into the North Pacific, upwell to mid-depth, mix with surrounding wa-ters, and return south (Schmitz 1996). In this configuration and as a result of mix-ing, the present North Pacific is charac-terized by high concentrations of surface nutrients, thus promoting high biologi-cal productivity. Today, no deep water forms in the North Pacific in response to surface buoyancy fluxes because the surface water of the North Pacific is not saline and dense enough to trigger deep convection and downwelling ( Warren 1983). However, in certain areas, such as the Okhotsk Sea, surface conditions are still favorable to form North Pacific Intermediate Water (NPIW) to depths of about 300 to 800 m (Talley 1993).
