WARM DEEP WATER 



93 



content of the warm deep water fell in a corresponding manner from west to east both 

 in the upper layers and at the depth of maximum salinity. The depth of the current 

 increased from west to east and the maximum temperature in the upper part of the layer 

 increased from i -40° to 1 -90° C. in the same direction. During the course of the cruise the 

 sdicate content fell from 4700 mg. to 3500 mg. in the upper layers and from 5100 mg. to 

 4500 mg. at the greater depth of the salinity maximum. The contents at the two positions 



5000 



O 



en 



2 



13 



2 4000- 



EASTWARD CRUISE 



O 5l0 2 AT MAX T° 

 X- X 5l0 2 AT MAX S %o 



Fig. 25. Graph showing the silicate content at the depths of maximum temperature and salinity of the warm 

 deep water in the ice-edge region of the South Pacific Ocean in January-March 1934. 



in the current during both cruises are shown in Fig. 25. The fact that the silicate content 

 of the warm deep water in this part of the ocean is less in the east than in the west must 

 be due to the fact that the general direction of movement of the current is towards the 

 east and south. The increase in temperature of the current towards the east suggests 

 that the eastward current of warm deep water from the region south of Australia must 

 be joined by warm deep water from the north and such water would have a lower silicate 

 content. During the eastward movement, mixing must occur at the upper and lower 

 boundaries, and since the neighbouring water masses are poorer in silica the content of 

 the current will decrease from west to east. 



