3o8 DISCOVERY REPORTS 



on this account alone, for at other seasons the agreement is good. The figures given in 

 Table 2, obtained over the short period covering the main increase in the locality in 



ZOOOt 



1500 



1000 



500 



JuIl) August September October November December Januarq Febru3rL| March April Mau June 



Fig. lo. Northern Region. Annual variation in plant pigments per m.^; means of all available observations 

 (50-0 m. hauls) at mean dates. Numbers of observations in brackets. Note anomalous figure for November 

 mentioned in text. 



question during the circumpolar cruise in 1937, clearly show how maximal values were 

 observed early in December in spite of the November values being lower than else- 

 where. 



Table 2 



The very close agreement between nutrient salt content of the water and estimated 

 quantities of plant pigments is also clearly shown by this table. It would not be so 

 good over a longer period when the effect of the biological uptake would be masked by 

 regeneration or replacement in varying degrees, but it seems to me that if our Harvey 

 estimations do not reflect the real quantity of phytoplankton production fairly closely, 

 the high degree of correlation with chemical data obtained quite independently by our 

 hydrologists at the critical period would be utterly impossible. 



