HYDROLOGY OF THE BRANSFIELD STRAIT 5 



is shown in Fig. 2. 1 It will be seen that the contours of the sea-bottom in the Bransfield 

 Strait are very irregular, but the soundings show that the strait itself is practically cut 

 off on all sides by land masses or by submarine ridges which will be described later. 

 Since soundings of over 2000 m. are recorded and confining ridges, varying between 

 600 and 250 m. in depth from the surface, have been discovered, it follows that the 

 Bransfield Strait consists of a deep basin shut off on all sides. These ridges restrict 

 the deep water in the Bransfield Strait from contact and free circulation with that 

 of the seas outside. This has a marked effect on the temperature of the water in 

 the Strait below the level of these submarine ridges. The existence of very low 



Fig. 2. Bathymetric chart of the Bransfield Strait. Soundings in metres. 



temperatures in the water below 300 m. has been noted by many expeditions, and 

 the probable existence of submarine ridges has been postulated by reason of the pre- 

 sence of these temperatures, taken in conjunction with the few soundings available before 

 echo-sounding was used. Thus O. Nordenskjold (1917, p. 9): "Deuten also schon 

 die Lotungen an, dass hier ein allseitig abgesperrtes Tiefenbecken vorliegt, so wird 

 dies in eklatanter Weise durch die Messungen der Wassertemperaturen bestatigt, und 



1 This chart is based on that published by Herdman, 1932, pi. xlvii. 



