ANTARCTIC INTERMEDIATE WATER 77 



In the western part of the South Indian Ocean the intermediate current has a higher 

 content than in the eastern South Atlantic. Outside the region of the Agulhas current 

 the content at the salinity minimum varied between about 1500 mg. and 2200 mg. 

 between 22 and i° S. 



South of Australia the silicate value at the nucleus of the current was of the order of 

 1900 mg. near Fremantle, falling southwards to about 1400 mg. and then increasing 

 to 1900 mg. again at the most southerly station in the sub-Antarctic zone. 



South-east of New Zealand two sections made in different years gave contrary results 

 and need to be repeated in subsequent cruises. 



WARM DEEP WATER 



PHOSPHATE AND SILICATE CONTENT 



For the following description of the warm deep water I am chiefly indebted to Deacon 

 (1937). This current can be recognized everywhere as a layer of high salinity underlying 

 a poorly saline layer. In the Antarctic zone it is also recognized by its relatively high 

 temperature between the low temperatures of the surface and bottom waters. In the 

 sub-Antarctic and subtropical zones it underlies poorly saline sub-Antarctic and Antarctic 

 intermediate waters. 



In the South Atlantic Ocean it can be traced from its place of origin in the North 

 Atlantic, where highly saline water sinks from the surface to great depths and flows 

 southwards, rising at the Antarctic convergence to a depth of about 250 m. Near 

 South Georgia this water climbs towards the south as far as about 52°-53° S without 

 interruption. South of 53 S the deep water belongs chiefly to a current from another 

 source, flowing from the southern and eastern parts of the Scotia Sea. North of the 

 Weddell Sea the temperature of the warm deep water decreases suddenly towards the 

 south in about 6o° S, and between the warm deep water found north of this latitude 

 and a further warm region near the Antarctic Continent the deep water is so cold that 

 it can only belong to an eastward movement of deep and bottom waters from the Weddell 

 Sea. Against this cold current the southward movement of North Atlantic deep water 

 comes to an abrupt end. In the eastern part of the South Atlantic Ocean the North 

 Atlantic deep water reaches as far south as 55°-56° S. 



In the region south of the Indian Ocean the warm deep current flows as far south as 

 the continental slope of Antarctica. In the neighbourhood of the slope it bends towards 

 the west into the Atlantic Ocean, where it is found as a warm current to the south of the 

 cold current which flows eastwards from the Weddell Sea. The southward movement 

 in the western part of the Indian Ocean is mainly formed of North Atlantic deep water, 

 but it also contains water in its upper layers from a similar origin in the northern part 

 of the Indian Ocean (Clowes and Deacon, 1935). In the eastern part of the subtropical 

 and sub-Antarctic zones of the Indian Ocean the deep water is less saline, colder, and 

 poorer in oxygen than the deep water in the west. These properties suggest that it is 



