4 8 



DISCOVERY REPORTS 



in 47 45' S, 114 5' E, south of West Australia, was recovered 870 miles farther north 

 after an interval of 7 years, and Krummel makes the reasonable suggestion that the 

 bottle had made a complete circumpolar drift. 



Below the well-mixed poorly saline surface stratum, the salinity section in Fig. 13 

 shows that there is a more saline subsurface stratum; it lies at a depth of 80-200 m. 

 Below it there is another type of poorly saline water — the main body of the sub-Antarctic 

 layer — which is known to flow northwards as well as the surface water, and since the 

 subsurface current maintains its high salinity between these two poorly saline currents 

 it must flow in the opposite direction towards the south. 1 



LATITUDE 

 STATION 675 

 I 



5r54;~ 



35°S 



40 



673 



I 



• 5-16- 



.b-IO 1 r — »toli 'O CU 



-J™ v, V R-nn. -~^ 



-> »i f A / 



500m 



1000m 



1500m --• 



5TC 

 I 



45 v 



671 

 I 



611- 



668 

 I 



6 20- 

 24 

 92 



AC 

 I 50° 

 666 



55 S 



663 

 I 



7-00 >" ^ • 7 - 2 ° ___2^6 6 y 



661 



I 



2000m 



Fig. 14. The vertical distribution of oxygen content in o to 2000 m. between 35 and 55 S. in 30 W. 



The path of the subsurface current is indicated approximately by the level of maximum 

 salinity. It is marked in Fig. 13 by the line AA, and its relation to the temperature and 

 oxygen distributions is shown in Figs. 12 and 14. The temperature section gives no 



1 H. U. Sverdrup (1934, p. 317) suggests the possibility that the surface and subsurface currents both 

 flow southwards, the difference of salinity between them being due to the greater dilution of the surface 

 water by precipitation. When this suggestion was made it was almost necessary to assume the existence of a 

 southward movement at the surface in order to explain the sharpness of the Antarctic convergence, but now 

 that the convergence is seen to be formed because the Antarctic water sinks as it passes over a steep slope 

 of the warm deep layer, and not simply because it flows up against a lighter surface water, the assumption is 

 no longer necessary. On the contrary a northward current must be assumed to explain the sharpness of the 

 subtropical convergence. The evidence given in the previous paragraphs seems to be sufficient justification 

 for this assumption. 



