Seasonal dissolved inorganic carbon variations in the Greenland Sea and implications for atmospheric CO2 exchange

During the 1993-1995 period of minimal deep convection in the Greenland Sea, the dissolved inorganic carbon concentration within the surface waters varied dramatically on the seasonal time scale, with average summer and winter values of 2064 ( +/- 10) and 2150 ( +/- 5) mu mol kg(-1) respectively, indicative of a vigorous annual carbon cycle. In contrast, there was very little interannual variability throughout these three years. While primary production largely depleted the surface nutrient supplies in spring and summer, generating a strong seasonal CO, drawdown, a combination of relatively shallow remineralization and mixed-layer deepening brought essentially all of the carbon consumed by photosynthesis back into contact with the atmosphere before winter. This re-release of the inorganic carbon that had been consumed by phytoplankton earlier in the year was more than sufficient to counteract the cooling-induced increase in the carbon carrying capacity of the water during fall and winter, reducing the potential for atmospheric carbon dioxide absorption by the Greenland Sea over the same period, (C) 1999 Elsevier Science Ltd. All rights reserved.