ANTARCTIC ADVENTURE AND RESEARCH 



Georgia (see Figure 7,^). Immediately at each side 

 of the island is a zone some fifteen miles broad very- 

 poor in plankton (floating organisms), and outside 

 this an encircling zone of thick plant plankton, largely 

 diatoms of the species Corethron valdivicr,^ and out- 

 side this again is an area of more mixed, but less dense, 

 plankton. This curious distribution is largely due to 

 the supply of phosphate which wells up from deep 

 waters along the west side of the island in response to 

 the dominant ocean currents. The diatoms growing 

 here are carried round to the sheltered northeast side 

 of the island, where there has developed an extremely 

 rich area of Etiphausia. This is perhaps why South 

 Georgia is one of the richest whale-feeding grounds 

 in the world. 



Political Regions in Antarctica 



We have seen already that there are no very well 

 defined regions in the Antarctic so far as we know at 

 present. There is a general tendency to call that region 

 east of the Greenwich meridian East Antarctica and 

 that in the other half of the time-circle West Ant- 

 arctica. This division links King Edward Land with 

 Graham Land and Coats Land, and splits the Ross Ice 

 Shelf between the two Antarcticas. The second method 

 of subdivision is to use four quadrants, opposite to the 

 three southern continents and the Pacific Ocean. The 

 third method is to ignore large divisions and discuss 

 each region according to the name given by its dis- 



3 Sketches of Corethron and Euphaiisia (not to scale) appear in 

 Figure 31. 



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