The Barents Sea Region supports some of the largest concentrations of seabirds in the world. A total of 33 species breed regularly in the region, and about 20-25 million seabirds harvest approximately 1.2 million tonnes of biomass annually from the area.Seabirds spend most of the year at sea, visit land only to breed and find all their food in the marine environment (Schreiber and Burger, 2002). Typically, they form large breeding colonies on inaccessible places along the coast or on remote islands.
Polar bears, seven pinniped species and five cetacean species reside full-time in the Barents Sea region. Eight additional whale species are regular seasonal migrants that come into the Barents Sea to take advantage of the seasonal, summer-time peak in productivity as the ice retreats northward. Three additional dolphin species are occasionally observed in the southern Barents Sea and sei whales (Balaenoptera borealis) have been observed north of 79° off the west coast of Spitsbergen, but these
Benthic ecosystems in the Barents Sea have considerable value, both in direct economic terms, and in their ecosystem functions. Benthic fauna are an integral component of the ecosystem, and benthic processes are tightly linked to total system dynamics. A total of 3,245 faunal taxa have been recorded — of this total, benthic macrofauna (60%) and meiofauna (34%) make up the majority — and more than 3,050 species of benthic invertebrates inhabit the Sea (Sirenko, 2001).
The Barents Sea has a number of water masses with the relatively warmer and more saline (>35) Atlantic Water which flows through the southern part of the Barents Sea, and the colder, less saline (34.4-35) Arctic Water to the north. The boundary between these two water masses is marked by the Polar Front, and the different physical and chemical properties of these water masses influence the growth and development of the resident phytoplankton species (Loeng and Drinkwater, 2007).
In the Barents Sea ecosystem, zooplankton forms a link between phytoplankton (primary producers) and fish, mammals and other organisms at higher trophic levels. The most abundant zooplankton species — calanoid copepods, krill, and hyperiid amphipods — form the major diet of herring, capelin, polar cod, and juveniles of other fish species. The Arctic front in the Barents Sea marks the boundary between the mainly Arctic zooplankton species (Calanus glacialis and Themisto libellula) and the Atlantic/subarctic species (C. finmarchicus, Meganyctiphanes norvegica, Thysanoessa spp and Themisto spp).
In this chapter we handle species of particular conservation concern due to their population status. These are the species present in the Barents Sea area and listed on the Global Red List (IUCN, 2008), the Russian Red Data book (Danilov-Danilyan et al., 2001 - Russia is preparing a new edition of the Red Book of the Russian Federation, in which will change the lists and categories of the rarity of certain species, subspecies and populations of animals. But while the book is not published,
Typical of other oceans, 6 types of microbes (single-celled microorganisms) occur in the Barents Sea: Archaea, Bacteria, Viruses, Fungi, Protista, and Microbial Mergers. In biogeochemical cycles of the ocean, a multitude of processes are catalyzed by Bacteria and Archaea; functioning of these cycles in the Barents Sea do not differ qualitatively from those at lower latitudes. The carbon cycle serves well as an example of a biogeochemical cycle (Figure 2.4.1).
Recent data indicate that more than 200 fish species representing 70 families occur in the Barents Sea (Dolgov 2004; Bogstad et al., 2008). Predominant families are: eelpout (Zoarcidae), snailfish (Liparidae), codfish (Gadidae), sculpin (Cottidae), flatfish (Pleuronectidae), and rockling, ling, and tusk (Lotidae). These families account for nearly 80% of the species regularly occurring in the Barents Sea, and more than 40% of the species recorded in this region (Dolgov et al., 2011).
At present, fish are the best indicators of the health of the aquatic environment and of changes due to anthropogenic stressors. The frequency of occurrence of diseases is a valuable indicator of the actual state of the Barents Sea ecosystem and can be useful to identify factors causing negative impacts. Monitoring long-term changes in the prevalence of diseases is needed to determine if/how they correlate with human activities and impacts (Karasev et al., 2011).