THE TRANSPORT OF ANTHROPOGENIC CARBON-DIOXIDE INTO THE WEDDELL SEA

Total carbonate data from the southern Weddell Sea, collected during the Swedish Antarctic Expedition in 1988-1989, has been investigated with respect to its content of anthropogenic carbon dioxide. The measured data was corrected for decay of organic matter by the use of the apparent oxygen utilization and the ratio of carbon to oxygen in organic matter. Correction due to precipitation or dissolution of metal carbonate was not found to be necessary from alkalinity and calcium data. With a combination of the water mass mixing conditions and the atmosphere-ocean carbon dioxide exchange, the anthropogenic input of carbon dioxide has been estimated. The anthropogenic carbon dioxide mean concentration varies in the different water masses as a result of the mixing conditions, from about 36-mu-mol/kg in the Ice Shelf Water to 8-mu-mol/kg in the Antarctic Bottom Water. The data were combined with oceanographic information in order to elucidate the ventilation of carbon dioxide in the Weddell Sea. With the outflow of Ice Shelf Water from the Filchner Depression equal to 0.7 x 10(6) m3/s (Foldvik et al., 1985), the annual transport of anthropogenic carbon amounts to 8 x 10(12) g for this special area. There are indications of other areas with significant deep water formation, but it is unlikely for these to add more than 2 times that of the Filchner Depression. This results in a total sequestering in the Weddell Sea of less than 1% of the annual anthropogenic emission of about 5.5 Gt C.