64 



Pamela G. Jenkins 



nt 30 



Fig. 2. Variation in chlorophyll, January-April 1953 at El, in mg/m^. 



The two winter months showed no appreciable change (Fig. 2), but from March 

 onwards the samples gave a high value of chlorophyll at the surface and even at 70 m, 

 giving a bottom maximum at 70 m of 78 -8 mg/ra^ on March 25th. These high readings 

 for the lower depths showed that the cells must have sunk. Riley (1941 b) observed 

 this high concentration of chlorophyll from 40-70 m at Georges Bank during March 

 and April. Marshall and Orr long ago (1928) reported that " during the spring 



m 30 



"O " lO "^ ^O 30 3 40 SO 60 7C 



mq/m 



Fig. 3. Variation in chlorophyll, May to August 1953 at El, in mg/m^. 



