SECT. 1] THK INFLUENCE OF ORGANISMS ON THE COMPOSITION OF SEA-WATER 



69 



It is difficult to believe that the character of the organic matter being 

 oxidized differs as greatly with depth as the results indicate. Riley finds that 

 errors in the data or analytical procedures cannot account for the discrepancy. 



50°N 



1000 



2000 



° 3000 



4000 



Fig. 16. Mathematical model of phosphate distribution along a north-south profile of 

 the Atlantic Ocean estimated from analytically determined physical coefficients and 

 assumed phosphate regeneration rates that vary in accordance with a generalized 

 hypothesis derived from analysis. Contour interval, 0.2 mg atoms P/m 3 . (From Riley, 

 1951.) 



The whole analysis is so complicated, however, that it is not possible to make 

 a satisfactory analysis of errors. Some degree of anomaly in the oxidative ratio 

 undoubtedly exists, but it is questionable whether the variations are as extreme 

 as the calculations indicate. 



E. The Biochemical Circulation of the Oceans 



Oxygen and phosphorus are distributed in the oceans of the world in charac- 

 teristic patterns which are described by Sverdrup et al. (1942). In the case of 

 the Atlantic Ocean, Riley's analysis evaluates in detail the factors on which 

 the dynamic balance underlying the pattern depends. It is of interest to examine 

 in a more general way the character of the circulation of the oceans to find 

 what dominant physical features create these patterns and account for their 

 differences. 



a. The vertical distribution of nonconservative elements 



The distributions in depth of phosphate and oxygen display a similar pattern 

 in the central basins of all oceans. Phosphate is depleted near the surface, rises 

 to a maximum at moderate depth and then decreases somewhat and is relatively 

 uniform in deep water (see Fig. 4). The distribution of oxygen follows an 

 inverse pattern. The depth at which oxygen is minimal corresponds roughly, 

 but not exactly, with that at which phosphate and nitrate are maximal and 



