THE KARA SEA 



237 



{Calanus finmarchicus, С hyperboreus, Pseudocalanus elongatus, Microcalanus 

 parvus, Oithona similis) and some salps (Fritillaria borealis and Oikopleura 

 vanhoeffeni and others). The cold-water forms are characteristic of the deep 

 water of the Kara Sea (below the 50 to 100 m layer) — Calanus hyperboreus, 

 Euchaeta glacialis, Metridia longa, Conchaecia borealis, Parathemistq oblivia, 

 Euthemisto libellula, Diphyes arctica and Clione limacina. 



Of the upper layer of water the following are characteristic : Pseudocalanus 

 elongatus, Oithona similis, Centropages hamatus, Thysanoessa neglecta, Temora 

 longicornis, Acartia longiremis, Oithona plumifera var. atlantica, Microsetella 



Fig. 103. Distribution of plankton forms 



which have penetrated from the north and 



forms from inland discharge in the Kara Sea 



(Virketis). 



norvegica, Oikopleura labradoriensis ; among the sea- weeds Halosphaera viridis 

 is the most typical. Most of these forms have arrived from the west. 



The quantittaively richest form, Calanus finmarchicus, in its mature state, 

 lives in the deepest layers of water, but while young is adapted to the upper 

 zones. The forms of western origin come into the Kara Sea from the Barents 

 Sea, either skirting Novaya Zemlya from the north or through the southern 

 passages. At times only a few penetrate into the Kara Sea (Fig. 103); some- 

 times, however, they go far to the eastward, as far as the passages into the 

 Laptev Sea. 



The ciliates Salpingella acuminata, Acanthostomella norvegica, Evadne nord- 

 manni, Podon leuckarti, meduse — Rathkea octopunctata, Crustacea — Evadne 

 nordmanni, Podon leuckarti, Centropages hamatus, C. typicus, Temora longi- 

 cornis and Oithona atlantica are included in this group of forms. 



The third group of cold-water Polar forms, penetrating from the north, is 



