Uptake of atmospheric carbon dioxide in the Barents Sea

The uptake of atmospheric carbon dioxide has been estimated from data collected in 1999 along a transect in the Barents Sea ranging from 72.5°N, 31°E to 78.2°N, 34°E. The uptake has been calculated from the change in total dissolved inorganic carbon, total alkalinity, nitrate and salinity in the water column and from the conservation of mass. The average uptake of carbon dioxide in Atlantic water from late winter until the time of investigation (about 3 months) was estimated to be 29±11 g C m−2. The uptake estimate has been compared with integrated air–sea flux calculated from the wind speed and the difference in fCO2 between the atmosphere and the ocean. The computed air–sea flux has been compared to estimates of new production, with the latter having a clearer trend of decreasing values with increasing latitude than for the air–sea flux. This could be explained by the decreasing surface water temperature with increasing latitude, indicating that cooling (increasing the solubility of CO2) is an important factor in driving the air–sea flux. This fact might be different if our study had been performed later in the season.