1 82 



DISCOVERY REPORTS 



PHOSPHATE AND TEMPERATURE 



Comparing the temperature sections of two lines which show extremes of high and 

 low phosphate abundance, Cape Carranza and Pichidanque Bay, it will be seen (Figs. 

 54 and 55) that upwelling was active or had until very recently been active in the first 

 within 58 miles of the coast, the temperature rising 2-12° with a gradient of 0-037° per 

 mile, while in the second there was next to no upwelling except for the first few miles, 

 the temperature showing no appreciable increase within 74 miles of the shore. The 

 line off Caldera affords an equally good illustration (Fig. 56). The line may be resolved 



STATION NUMBER5_WS60I 

 MILES FROM COAST_ ' 



VMS600 WS599 WSSSa WS537 



W5533 

 WSSSe WSS35WS594 I 



200- 



300- 



100- 



SOUNDING IN METRES_ 5437 - 3ZSS 2307 1593 



Fig. 54. Distribution of phosphate (per m.^). Section off Cape Carranza, May iS-20. Corresponding 

 sections of temperature and saHnity are illustrated on p. 138. 



into two parts : within 25 miles of the shore turbulence and upwelling seem phenomenal ; 

 from 25 to 50 miles offshore the isotherms run level. Corresponding to these two parts 

 we find that surface phosphate values in the upper layers from 25 to 50 miles are mini- 

 mal, whereas in the upwelling region they are medium. Moreover, rich phosphates are 

 nearer the surface in the upwelling region than offshore. Off Antofagasta the phosphate 

 content at the surface changed from rich to medium with change of wind and increase 

 of temperature (Figs. 58 and 59). Off San Juan, the surface temperatures over the 

 regions of high, medium and low phosphate concentration are respectively i3-79-i5-36° 

 C, i6-24-i7-4° C, and i8-8o-i9-48' C. Correlation between phosphate distribution 

 and temperature in these five localities is straightforward because the area of disturb- 



