210 BIOLOGY OF THE SEAS OF THE U.S.S.R. 



Lichenopora verrucaria, Crisia eburnea, the polychaete Spirorbis borealis and 

 the crustacean Caprella septentionalis. Certain littoral forms come down from 

 above, such as Mytilus edulis, Littorina rudis, Rissoa aculeus and others. To 

 the dominant forms mentioned there are added numerous hydroids, bryozoans, 

 molluscs, nemertineans, the characteristic sucking-fish Cyclopterus lumpus 

 and others. Rhizoid Laminaria, which attach themselves to rocks, forming a 

 tent-like structure, give shelter to a rich fauna, and chiefly to the polychaetes 

 Nereis pelagica, Phyllodoce maculata, Castalia punctata, Harmothoe imbricata, 

 Pholoe minuta, and amphipods Amphitae rubricata and Jscheroceros anguipes, 

 the gastropod molluscs Margarita groenlandica, M. helicina and Rissoa 

 aculeus, the brittle stars Ophiopholis aculeata and Ophiura robusta ; the star- 

 fish Asterias rubens, and many other polychaetes and molluscs. On bare sandy 

 patches, among the Laminaria growths, there settles the fauna of animal forms, 

 of which some dig themselves into the sea-bed {Macoma calcarea) and some 

 crawl about on it {Asterias rubens, Cribrella sanguinolenta, Ophiura robusta, 

 various gastropod molluscs, and others). 



The White Sea biological station of Moscow University has carried out 

 investigations of the bottom fauna of Rugozerskaya Inlet, in the southern 

 part of the Gulf of Kandalaksha (Fig. 90), and divided it into five basic bio- 

 coenoses. In the outer part of the Inlet, at a depth of 6 to 12 m, is located a 

 biocoenosis Styela rustica, Potamilla reniformis, Astarte, and Ophiura robusta. 

 Sea-bed : silty-sand ; average biomass : 243 g/m 2 . Farther up the Inlet, at a 

 depth of 4-5 to 14 m, and on sand and mud, is located a biocoenosis Serripes 

 groenlandicus, Terebellides stromi, Pectinaria koreni, Ophiura robusta; mean 

 biomass : 32 g/m 2 . In the central part of this area there may be distinguished 

 a biocoenosis Cyprina islandica-Stegophiura nodosa, with a biomass of 96 

 g/m 2 . In the shallow areas of this region, near the shore at a depth of 4 to 5 m 

 and on soft mud where there are dead Zostera, is located a biocoenosis with 

 a considerable intermingling of relict brackish-water forms : Pontoporeia 

 femorata, Nephthys paradoxa, Mysis oculata, and Cumacea. The mean bio- 

 mass of this is 25 g/m 2 . In that part of the Inlet, where there is soft mud with 

 dead Zostera at a depth of 3-5 to 6 m, is located a biocoenosis Macoma baltica- 

 Nephthys paradoxa-Scohplos armiger, with a biomass of 30 g/m 2 . In the 

 inner part of the Inlet salinity falls at ebb-tide to 3 to 4 per cent, and at flood- 

 tide it rises to 21 to 22 per cent in the surface layer and to 22-5 per cent in the 

 bottom layer. 



G. Gurvich and I. Ivanov (1939) give a description of several benthic com- 

 munities in the upper level of the sublittoral on soft bottoms in the area of 

 Umba (Gulf of Kandalaksha). At a depth of 4 to 6 m they distinguish a com- 

 munity with the following predominant forms : polychaetes, Terebellides 

 stromi and Scoloplos armiger; echinoderms, Ophiura robusta and Asterias 

 rubens; the bivalve Astarte montagui; and the small Cumacea Brachydia- 

 stylis resime; the biomass of this community is 89 g/m 2 . 



Below the Laminaria zone (10 to 45 m) extends the level of the red algae: 

 Phyllophora, Rhodophyllis, Delesseria, Polysiphonia and others. 



As Derjugin points out (1928) : 'This level is rich in life, and in it one may 

 evidently distinguish certain groups which have not yet been studied in detail. 



