[en] Pelagic and benthic processes were determined in the nothern Bay of Biscay when coccolithophores blooms occured between 2006 and 2008. Here we present a synthesis of pelagic primary production, calcification and respiration and benthic respiration and dissolution of CaCO3. Or results suggest that CaCO3 dissolution in the surface sediments is small (~1%) compared to integrated pelagic calcification. Benthic respiration increases with the organic load of the sediment and represents ~8% of the integrated pelagic respiration. The relationship between dissolution and respiration rates suggests a metabolic driven dissolution in waters supersaturated with respect to calcite (omega>3.5). We address a mass balance of the described processes and associated CO2 fluxes in the water column.