THE BARENTS SEA 153 



also present are the molluscs Astarte crenata, Cardium ciliatum, C. groen- 

 landicum and Pecten islandicus. Still farther into the inlet this rich fauna 

 grows poorer, many forms are not found and a series of forms peculiar to 

 sandy shallows make their appearance — Scoloplos armiger, Cyprina islandica, 

 Yoldia hyperborea, Macoma calcarea and others. 



On the cliffs and rock floors of the great depths of the outer parts of both 

 inlets, especially in the Kola Inlet, lives the community Porifera-Brachio- 

 poda-Bryozoa, and slightly above it lives the great community Ascidia 

 obliqua, often with a biomass of more than 1 kg/m 2 . Still higher is the Balanus 

 belt, with Balanus balanas, Ophiopholis acideata, Thelepus cincinnatus, Pseudo- 

 potamilla reniformis, Modiola modiolus, Pecten islandicus, Miynchonella psit- 

 tacea, and containing a mass of bryozoans and hydroids. 



In the outer parts of the Motovsky and Kola Inlets and east of the Gavrilov 

 Islands, on the sandy beaches of the sublittoral of the upper horizon is re- 

 corded an original fauna, developed in large numbers, primarily the molluscs : 

 Cyprina islandica, Mactra elliptica, Dentalium entalis, Macoma calcarea, 

 Astarte crenata, A. montagui and others. 



A large number of warm-water boreal species are encountered there, and 

 there is a considerable similarity with the sublittoral communities of the Nor- 

 wegian coast. As we have seen above, the littoral fauna there has a more 

 sharply pronounced warm-water character. On the other hand in the great 

 depths of the inlets, in the zones of a weak vertical circulation and cold 

 stagnant waters some cold-water Arctic forms have found shelter, and as one 

 moves farther up the inlet, the higher do the cold-water forms ascend. Hence 

 considerable summer heating of the surface waters of the enclosed parts of 

 the inlets, and the presence of cold stagnant waters at shallow depths, results 

 in a. sharp vertical zonation of the fauna. Many representatives of the shallow- 

 water, littoral and upper sublittoral boreal fauna find here their extreme limit 

 of propagation to the east, and the Arctic fauna their extreme westerly limit. 

 A vertical displacement of fauna of different thermophilic aspects at the 

 border-line of their habitats is a common phenomenon. As has been pointed 

 out by V. Zatzepin (1939), in some individual bights of the Motovsky Gulf 

 (Ara, Ura, Zap. Litza), as a sequence of the submarine barriers, the depths 

 are filled with cold stagnant waters, inhabited by cold-water species. By 

 contrast, in bights not separated from the sea by submarine barriers, and not 

 having a deep stagnant zone (as, for example, Teriberka, Yarnyshnaya), most 

 of the sublittoral is inhabited by warm-water communities represented by 

 such forms as Cyprina islandica, Mactra elliptica, Cardium fasciatum, C. ele- 

 gantulum, С echinatum and Modiola modiolus. The central parts of the inlets 

 are, however, inhabited by cold-water forms such as Pandora glacialis, Lyonsia 

 arenosa, Serripes groenlandicus, C. ciliatum, Pelonaia corrugata and others. 



The bottom population of Sturfjord to the east of Spitsbergen is quite 

 peculiar (V. Brotzkaya, 1930). This very wide and shallow (25 to 100 m) inlet 

 with its negative bottom temperature is climatically one of the most inclement 

 corners of the Barents Sea. Sturfjord is free for only a very short time of the 

 sea ice and icebergs which usually block it. Numerous glaciers come right 

 down to the water so that even in the warmest season of the year, the waters 



