and has to return south along the Madagascar Ridge. It has the char- 

 acteristics of a western boundary current which is deflected away 

 from the continental slope by the bottom topography. 



The oxygen content in the salinity maximum is also used to con- 

 firm the flow of the Atlantic water. To the south of the Mid-Oceanic 

 Ridge the Atlantic water is important^ vhereas to the north of the 

 ridge water of North Indian Ocean origin is predominant as shown by 

 comparative oxygen values. North of the ridge the oxygen content 

 in the salinity maximum was 3« 57 to 3« 68 ml/l._, while to the south 

 of the ridge it was 3.99 ml/l.^ 



It appears that the northward flow of Atlantic deep water in 

 the Agulhas Basin is strengthened by a similar flow of Antarctic 

 Bottom Water because the oxygen content increases toward the north 

 while the salinity and temperature decrease. This is probably due 

 to vertical mixing between the two water masses. 



Ifeta from three cruises of the Australian research vessel 

 Diamantina were used by Wyrtki^ to calculate geopotential anomalies 

 and circulation in the southeast Indian Ocean. A constant depth of 

 1,750 meters was selected as a reference level or surface of no 

 motion. A strong current to the south was observed along the coast 

 of Australia as the result of a cyclonic eddy to the west of Perth. 

 This eddy is centered at 32°S, 110°E and is remarkably well devel- 

 oped even at the it-OO decibar level. 



^Ibid. 



^K. Wyrtki, "Geopotential Topographies and Associated Circu- 

 lation in the South-Eastern Indian Ocean^" Australian Journal of 

 Mirine and Freshwater Research, XIII (June 19'52j, pp. 1-17' 



51 



