THE BARENTS SEA 129 



bay (in particular the mass population of the urchin Brisaster fragilis) and the 

 southern part of the bay, from which a number of cold-water forms (for 

 instance Serripes groenlandicus) have disappeared. 



With a wide variation of species the Kola Inlet fauna has only 20 to 30 

 species of polychaetes, bivalves, echinoderms and Gephyrea composing the 

 basic mass of its population. 



As in the open parts of the Barents Sea polychaetes are preponderant at 

 great depths and on softer bottoms and the bivalves at lesser depths and on 

 harder floors. 



The communities of the deep ooze and sand-ooze bottoms are very similar 

 in their composition to those of the adjacent open parts of the Barents Sea 

 (group II, see below). 



In the Motovsky Bay, owing to its wide and free connection with the open 

 sea, before it joins the bight of the Kola Inlet and in its northern part, the 

 communities Cyprina, Macoma and Mactra, which inhabit warmer water, 

 are strongly developed ; a large number of warm- water boreal species are 

 found here. The cold-water species are concentrated in the south of the Inlet. 



Up to 80 per cent of the deep part of the Kola Inlet (Fig. 49) is occupied by 

 a typical Barents Sea biocoenosis with a preponderance of Spiochaetopterus, 

 Maldane, Astarte, Ctenodiscus, Phascolosoma and Strongylocentrotus (see 

 below). 



Zatzepin has distinguished in the deep part of the Kola Inlet, from north 

 to south, five variations of the above-mentioned biocoenoses ; for four of them 

 data are given in Table 53, and their distribution is shown in Fig. 49. These 

 four variations are distinguished by the preponderance of individual forms in 

 the biocoenoses components, but the basic composition remains unaltered. 

 Towards the south the dominant forms change. At first we find Astarte 

 crenata and Maldane sarsi, then Onuphis conchilega, Strongylocentrotus droe- 

 bachiensis, Nicomache lumbricalis, and finally in the southern part of the Inlet 

 Cardium ciliatum and Cyprina islandica. In the shallow holes of the Kola 

 Inlet another variant with the leading forms of Cardium ciliatum, Macoma 

 calcarea and Maldane sarsi is formed on sandy silt. Moreover of the char- 

 acteristic forms widely distributed throughout the whole Barents Sea there 

 are worms Spiochaetopterus typicus, Myriochele oculata, Nephthys ciliata, 

 Lumbriconereis fragilis, Phascolosoma margaritaceum, Phascolion strombi, 

 Rhodine gracilior, molluscs Portlandia lenticula, P. intermedia, Area glacialis, 

 Pecten islandicus, Yoldia hyperborea, Nucula tenuis, echinoderms Ctenodiscus 

 crispatus, Ophiura sarsi, with Ophiopholis aculeata and Terebratulina septen- 

 trionalis among the branchiopods. The sandy bed of the southern part of the 

 bay is inhabited by the biocoenoses Cardium ciliatum and Cyprina islandica. 

 Among the characteristic forms the polychaetes Scoloplos armiger, Pecti- 

 naria hyperborea, Myriochele oculata and Lumbriconereis fragilis, the molluscs 

 Yoldia hyperborea, Macoma calcarea and Axinus flexuosus and the echino- 

 derms Ctenodiscus crispatus and Myriotrochus rincki should be mentioned. 



With all its qualitative changes within the limits of the two communities 

 considered, the biomass is not large (Fig. 49a) ; it varies from 25 to 200 g/m 3 , 

 rarely reaching this upper limit. 



