cr rrrrr 



10 



to 



u 



0) 



XI 



100 



60 



200 



XIOO 

 \ 



^ 



f^^^'S'STrrto' 



too 



no 



OJ 



200' 



too -~ m 400 



»^4,.\r II 



r 2'3'r 5' 6'7'8 9-iO-tr 



200 i 



m 



I o-rrjrTBT 



50 



hyperboreas 



m 



mg/m3 



Figure 14. Variations in biomass of plankton in dependence on variations in water temper- 

 ature. I. Near the southern edge of the East Icelandic current (station No. 67, 

 19th May 1953); II. In the southern central part of the Norwegian Sea, in mixed 

 waters (station No. 108, 16th June 1953); III. To the north-east of the Faroes, 

 in the waters of the East Icelandic current (station No. 110, 22nd June 1953); 

 IV. To the north-east of Jan Mayen, in mixed waters (station 134, 13th July 

 1953). Vertical scale: Depth in metres. 



In the Central Basin (western part), on the Central Plateau, and in the area of Jan Mayen 

 there is a {wpulation of two species of Amphipoda: Themisto abyssorum, whose habitat includes 

 the "patch" of Oikopleura, and Themisto libellula, whose habitat lies along the northern boundary of 

 the Norwegian Sea and further west. The species Th. libellula predominates in the Greenland Sea 

 (see Figure 5). 



During the 1953 season, the principal species of Copepoda in the plankton was Pseudocalanus 

 elongatus , which was found everywhere in the 0-25 metre layer. Its quantity increases in the cur- 

 rents, (see Figure 4). Thus, in the middle of May, Y_^ elongatus was found in considerable quan- 

 tities near the Faroes in latitude 63°N and longitude 3°W. The quantity increases towards the north, 

 especially in the western current. 



In the area of Jan Mayen, P. elongatus is usually found in the 50-metre layer in association 

 with Oithona similis and Oncea borealis . 



98 



