HOW MUCH DEEP-WATER IS FORMED IN THE SOUTHERN-OCEAN

Three tracers are used to place constraints on the production rate of ventilated deep water in the Southern Ocean. The distribution of the w ater mass tracer PO4 (''phosphate star'') in the deep sea suggests th at the amount of ventilated deep water produced in the Southern Ocean is equal to or greater than the outflow of North Atlantic Deep Water f rom the Atlantic. Radiocarbon distributions yield an export flux of wa ter from the North Atlantic which has averaged about 15 Sv over the la st several hundred years. CFC inventories are used as a direct indicat or of the current production rate of ventilated deep water in the Sout hern Ocean. Although coverage is as yet sparse, it appears that the CF C inventory is not inconsistent with the deep water production rate re quired by the distributions of PO4 and radiocarbon. It has been widel y accepted that the major part of the deep water production in the Sou thern Ocean takes place in the Weddell Sea. However, our estimate of t he Southern Ocean ventilated deep water flux is in conflict with previ ous estimates of the flux of ventilated deep water from the Weddell Se a, which lie in the range 1-5 Sv. Possible reasons for this difference are discussed.