Based on the Brotskaya and Zenkevich (1939) investigation, six main bottom community areas within the open part of the Barents Sea was defined. The south western Barents Sea (I, red area in figure 2.4.11) was characterized by its high abundance of boreal species and predominance of seston-feeders in biomass, whereas the central Barents Sea (II, light blue area in figure 4), at an average depth about 200m and on sandy silt, has a rather low biomass compared to other communities in the Barents Sea.
The species composition is very homogenous and made up primarily by the 4 dominant (in biomass) species including the polychaete Spiochaetopterus typicus, the bivalve Astarte crenata, the deposit-feeding sea star Ctenodiscus crispatus and the large sipunculid Golfingia margaritacea. In the eastern and south eastern part of the Barents Sea (III, green area in figure 2.4.11) there is a complex of communities occurring on silty and sandy sediment at depths less than 200 m. This complex is characterized by rather high benthic biomass where bivalve molluscs account for, on the average, half of the total biomass of benthos. Astarte borealis, Macoma calcarea and Clinocardium ciliatum are the predominant species in the communities of this complex.
The eastern and south eastern coastal communities (IV, yellow area in figure 2.4.11) occur on sandy bottoms in coastal shallow waters in the Pechora Sea, along the coast of Novaya Zemlya and Franz Josef Land. The bivalves Astarte borealis, Macoma calcarea and Serripes groenlandicum as well as sea squirts Pelonaia corrugata burrowing in the sand are predominant in biomass in this community. The biomass of coastal communities is slightly lower than in open waters of the south eastern part of the Barents Sea but still is at rather high level compared to other regions.
The Northern community (V, dark blue area in figure 2.4.11) is situated in the northern part of the Barents Sea on brown soft mud at 200-450 m depth. Low biomass and a high percentage of arctic deep-water species are typical for this complex. Large arctic ophiurids (e.g. Ophiopleura borealis) the large dolioform sea-cucumber Molpadia and, at some stations, bivalve mollusc Astarte crenata are predominant here. Finally, the Northern Barents Sea Shallow Water community (VI, white area in top of figure 2.4.11) is situated at 100 m depth at the archipelago of Franz Josef Land on sandy sediment with stones. This community is characterized by the predominance of epifauna and has a relatively high biomass.
Communities with a similar complex of dominant species were singled out in the shallow waters of Svalbard. Bivalve molluscs Hiatella arctica and Astarte borealis, barnacles of genus Balanus and the polychaete Thelepus circinnatus are predominant. All the species belong to the group of seston-feeders, and this complex is, therefore, characterized as typical for shallow waters with active hydrodynamics.
