DISTRIBUTION OF ANTARCTIC MACROPLANKTON 



151 



in the neighbourhood of the South Shetlands and South Orkneys, the Bransfield Strait 

 and eastern part of the Bellingshausen Sea. The Shetland-Orkney region and the 

 eastern Bellingshausen Sea can be regarded as subdivisions. It is characterized normally 

 by a very thin plankton in which typically cold-water species are well represented. In 

 some places there may be considerable irregularity in the quantity of plankton. The 



30° 



Fig. 48. Chart showing the provisional boundaries of areas in which distinctive plankton communities have 



been found. 



limits of this area are ill-defined near the South Orkneys, and uncertain on the west 

 side of Drake Passage. 



(3) The transition belt. Derived from Fig. 21, p. 105. This is the belt in which the 

 normal southern limits of the warmest water species and the northern limits of the coldest 

 water species are found. One would expect to find the cold-water species prominent 

 here in the early summer and the warm-water species later. This zone largely encloses 

 the line separating the waters derived from the Bellingshausen and Weddell Seas, and 

 may be taken to include South Georgia and the adjacent whaling grounds. Strictly 



