PHOSPHATE AND TEMPERATURE CORRELATION 



183 



ance was amply covered by our stations. Off northern Peru, however, the breadth of 

 cool water is greater and observations do not always extend through to typically oceanic 

 conditions. Thus rich phosphates at the surface near the Lobos Islands may be corre- 

 lated in their wide extent with the spreading seawards of the surface isotherms ; but the 

 contrast between waters that have long been at the surface and those recently upwelled 

 is not illustrated (Fig. 60). 



PHOSPHATE AND PHYTOPLANKTON 

 The relation between nutrient salts and phytoplankton may be shown in two ways, 

 firstly by the occurrence of rich phytoplankton only in those areas rich in nutrient salts. 



STATION NUMBERS_\N5G07 

 MILES FROM COtoT_ 125 



WSBDS 



loo 



wssoa 

 Ss 



W5605 WSGD3 

 WSBQ4 I W5G02 

 I I I 



100- 



200- 



300- 



SOUNDING IN METRES_ 3550 ~ " 8500 l£3B6a7 



Fig. 55. Distribution of phosphate (per m.^). Section off Pichidanque Bay, May 28-30. Corresponding 

 sections of temperature and salinity are illustrated on p. 139. 



and secondly, within those areas, by the greater depletion of nutrient salts at stations 

 where phytoplankton is thick than at those where it is poor. Table XI shows that 

 phytoplankton is in higher concentration within 100 miles of the coast than farther out 

 to sea. The phytoplankton inhabits the uppermost layers, and the uppermost layers are 

 rich in nutrient salts only close to the coast. Thus regarding this part of the eastern 

 South Pacific as a whole we note that phytoplankton and phosphate coincide in abund- 

 ance along the coastal region. This coincidence in the distribution of phosphate and 

 phytoplankton is seen to almost greater effect when the separate localities represented 

 by our lines of stations are compared with one another. The seven lines upon which a 

 complete series of phosphate analyses was secured have been arranged in order of 



