THE INFLUENCE OF FRESH-CORE RINGS ON CHEMICAL CONCENTRATIONS (CO2, PO4, O-2, ALKALINITY, AND PH) IN THE WESTERN SUB-ARCTIC PACIFIC-OCEAN

We here present conductivity-temperature-depth and chemical (CO2, PO4, O-2, alkalinity, and pH) observations across an anticyclonic (fresh-c ore) ring in the Oyashio Current near Bussol Strait, Kuril Islands. Th ese measurements suggest that the core of the ring is a region of enha nced vertical mixing, with attendant effects on both spatial and tempo ral patterns of CO2 exchange. In particular, the difference between at mospheric and oceanic pCO(2) at the air-sea boundary shows a pronounce d seasonal reversal in sign. In winter, pCO(2) is everywhere higher in the ocean than in the atmosphere; however, because mixing within the core of the ring brings additional amounts of deep, CO2 rich water upw ard the highest values of pCO(2) occur above the ring. In summer, pCO( 2) outside the ring boundary is also higher in the ocean than in the a tmosphere; however, because enhanced mixing within the ring now promot es high values of nutrient flux, primary productivity, and CO2 uptake, pCO(2) values there are lower than in the atmosphere. These data sugg est the importance of including mesoscale physical processes in the in terpretation of oceanic CO2 exchange and demonstrate the usefulness of biogeochemical properties in studies of ring dynamics and evolution.