36 



CHEMICAL RESULTS OF LAST CRUISE OF CARNEGIE 



per liter. Even at great depths some oxygen is con- 

 sumed by organisms and decomposing chemical sub- 

 stances, and table C4 shows that in the stratosphere a 

 considerable amount of the oxygen had been consumed. 

 The highest value obtained in the North Pacific, at 3500 

 meters, was only 3.25 ml per litfer. 



Table 04 also shows that the oxygen content in- 

 creases from south to north. This indicates that, since 

 at these depths the oxygen is not replenished by vertical 

 water movements, the water at the most southerly sta- 

 tions has descended from the surface more recently than 

 at the stations farther north. This means that in the cen- 

 tral and eastern Pacific the water in the stratosphere is 

 moving in a northerly direction. That the oxygen content 

 increases toward the south is further corroborated by 



the data published by Thomsen (1931b) who shows that at 

 all the stations occupied by the Dana south of the Carne - 

 gie stations, the oxygen content in the deep water was 

 considerably higher than that found at the southernmost 

 Carnegie stations. 



Only two of the Carnegie oxygen series in the south- 

 eastern Pacific extend to great depths. At both station 

 52 (latitude 31° 28' south, longitude 112° 51' west) and 

 station 57 (latitude 33° 59' south, longitude 106° 43' 

 west) the oxygen content at 2000 meters was about 3.5 

 ml per liter. This value is higher than those obtained 

 farther north in the central Pacific and further corrob- 

 orates the conclusion that the origin of the deep water 

 lies to the south. 



COMPARISON OF OXYGEN CONTENT OF THE ATLANTIC AND PACIFIC OCEANS 



The distribution of oxygen in the Atlantic is much 

 better known than it is in the Pacific. In the Atlantic 

 oxygen has been investigated, among others, by the fol- 

 lowing: Gaarder (1927), in the eastern basin of the 

 North Atlantic; Seiwell (1934), in the western basin of 

 the North Atlantic; Wattenberg (1929), in the Atlantic 

 south of latitude 20° north; and Deacon (1933), in the 

 western basin of the South Atlantic. 



In comparing the data published by the above inves- 

 tigators with those obtained in the Pacific, a striking 

 difference in the oxygen content of the deep water of the 

 two oceans is apparent. This difference can be illus- 

 trated by the data from two stations, one occupied by the 

 Deutschland (Brennecke, 1921) in the Atlantic at latitude 

 27° 46' north, longitude 27° 36' west, and the other by 

 the Carnegie (station 137) in the Pacific at latitude 24° 

 02' north, longitude 145° 33' west. The oxygen content 

 at these two stations is shown in figure C22. 



At the Deutschland station the water below 2000 me- 

 ters contained between 5 and 6 ml of oxygen per liter of 

 water and similar, or even greater quantities, were ob- 

 tained at seventy-five other stations investigated by the 

 Deutschland in the North and South Atlantic. At the 

 Carnegie station in the Pacific at this depth the oxygen 

 content was less than 3 ml per liter. Wattenberg (1929) 

 also found that below 2000 meters in the Atlantic the 

 concentration of oxygen was greater than 5 ml per liter. 

 According to his summary the oxygen content in the At- 

 lantic at all latitudes greater than 20° north or south is 

 practically the same as at the Deutschland station rep- 

 resented in figure C22. In the tropics, however, the 

 minimum oxygen values were lower and in the eastern 

 part of the Atlantic sometimes fell below 0.5 ml per 

 liter but even here the oxygen content below 2000 me- 

 ters was between 5 and 6 ml per liter. The Carnegie 

 obtained two oxygen series in the Atlantic. One, at sta- 

 tion 3, latitude 44° 00' north, longitude 36° 10' west, 

 shows very good agreement with that of the Atlantis 

 station 1157 in the same locality (Seiwell, 1934) except 

 that slightly high values were obtained in the deep water 

 The Atlantis values below 2000 meters were between 



5.5 and 6 ml per liter; the Carnegie values were 6.09 

 ml per liter. 



The series obtained at Carnegie station 8 (latitude 

 63° 30' north, longitude 14° 41' west) is interesting as 

 it shows conditions in high latitudes where there is no 

 thermal stratification of the water. It is thus evident 

 from the available data that at this station the quantity 

 of oxygen is nearly uniform from the surface to the bot- 

 tom, the quantity being about 6 ml per liter. 



In the Atlantic the stratosphere contains consider- 

 ably more oxygen than it does in the Pacific. Watten- 

 berg (1929) states that the high oxygen content of the 

 deep water of the Atlantic can be accounted for by the 

 fact that this water originates in the polar and subpolar 

 regions and that at great depths very little oxygen is 

 consumed. 



As shown in table C4 the oxygen content of the deep 

 water of the Pacific is decidedly below that at the sur- 

 face. The highest value obtained in the central Pacific 

 was 3.87 ml per liter at 3900 meters at station 161, 

 northeast of the Samoan Islands. It is thus evident that 

 the deep water of the central and eastern Pacific has 

 lost a much larger part of its original oxygen than has 

 the deep water in the Atlantic. From this it must be 

 concluded that, since there is probably no significant 

 difference between the two oceans in the rate of oxygen 

 consumption, the deep water in the Pacific has lacked 

 contact with the atmosphere for a longer period than has 

 the Atlantic deep water, either because the Pacific water 

 flows at a slower rate or is farther removed from its 

 sinking center. 



In this connection it is interesting to note that, as 

 shown in the other papers accompanying this report, 

 present knowledge indicates that the deep water of the 

 Pacific is richer in phosphate and silicate and has a low- 

 er pH, which means a higher carbon dioxide content, 

 than that of the Atlantic. These are further indications 

 that the deep water of the Pacific has lacked contact with 

 the surface layer for a greater length of time than has 

 the water of the Atlantic. 



