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DISCOVERY REPORTS 

 Owing to the northerly position of the ice-edge at this time of year (September-October 

 1936) most of the observations fell in the northern region of the Antarctic zone. They 

 showed the first small increase above the minimal winter values quite clearly. 



At South Georgia a considerable plankton survey was undertaken which showed the 

 main increase to be beginning sporadically during the last week of October, when three 

 really high phytoplankton concentrations were observed. During the first fortnight of 



Fig. 7. Positions of observations in the South Georgia area during the fourth 

 commission of R.R.S. 'Discovery IT. 



November observations were obtained suggesting a similar sporadic increase in some 

 parts of the Scotia Sea, but on a smaller scale, as we have learnt to expect. Farther 

 south, in the Weddell Sea, no production on a considerable scale was yet apparent. 



After an extensive series of observations in sub-Antarctic waters west of the Falkland 

 Islands, work was continued in the South Georgia area during the first three weeks of 

 December 1936. It appeared that the main increase was at or just past its maximum, 

 and many high values were recorded. In addition to the routine plankton survey three 

 24 hr. stations were worked in phytoplankton concentrations ranging from the highest 



