Excess atmospheric carbon dioxide transported by rivers into the Scheldt estuary

The transport of excess atmospheric CO2 (defined as the fraction of dissolv ed inorganic carbon (DIC) that can escape as CO2 to the atmosphere due to w ater-air equilibration), by the five rivers entering the Scheldt estuary is investigated. Excess CO2 originates from both respiration in the soil and the river and represents 10 % of the DIC and 6 % of the total carbon input into the estuary. The ventilation of this CO2 in the estuary is however a m inor contribution (10 %) to the total estuarine emission to the atmosphere, compared to heterotrophic activity and acidification due to nitrification within the estuarine zone. (C) 2000 Academie des sciences / Editions scient ifiques et medicales Elsevier SAS.