Arctic, Coastal Ecology
Basic Characteristics of the Arctic
The major marine ecosystems of the Arctic include the High Arctic oceanic region, which comprises the deep sea; the High Arctic coastal region between the abyss and the shore; the High Arctic brackish water subregion surrounding the shores of northern Russia, Canada, and Alaska, where the fauna must adjust to seasonal changes in temperature and salinity; and the boreal littoral region of Norway influenced by warmer currents which favor a faunal penetration from the south. Lastly, the Low Arctic shallow region marks the transitional area between the boreal Norwegian fauna and the High Arctic fauna.
The Arctic coastlines of Greenland, northern Iceland, Svalbard, northern Norway, Novaya Zemlya Islands, Murman coast, eastern Siberia, and Arctic archipelago of Canada are generally steep and deeply cut by fjords. However, the northern coast of Alaska, the Canadian Northwest Territories mainland, and most of the Arctic Russian coast are low relief coastal plains. The southern part of the Arctic coasts is characterized by the tundra biome where only grasses, mosses, lichens and about 400 flowering plants grow on a permanently frozen soil during short summers. Most of the biomass is in the root systems. The northernmost portions of Arctic landmasses, consisting mainly of the northeastern islands of Nunavut (Canada) and northern and central Greenland, lie under a permanent ice and snow cover.
Overall, much of the Arctic coastline is ice-covered for about 7 months a year and the water temperature generally remains below 0 °C. Air temperatures as low as −65 to − 68 °C have been recorded in Arctic Russia and Canada, and precipitation in the Arctic generally averages less than 250 mm per year. Melting and refreezing processes, wind-chill, runoff from the land and ice movement generate temperature and salinity variations in the upper water layer. The extreme seasonal oscillation in light is an additional factor affecting the biotic components of the Arctic ecosystem.
Due to its particular structure as a semi-enclosed sea (Fig. 1), the Arctic Ocean is fairly isolated from the other major oceanic masses, except through the Bering Strait, the Denmark Strait, and the Barents and Norwegian Seas. However, no invertebrate genus is endemic either to the Low or High Arctic. This suggests that most Arctic genera are distributed worldwide or at least found in the Atlantic, the Pacific, or both. Moreover, 77% of the Arctic genera are also common to the Antarctic.
The marine Arctic environment is generally perceived as stressful to the fauna and flora that live there (Menzies 1975). Low temperature is apparently not the primary factor that has shaped the Arctic marine ecosystem, but rather the marked seasonal oscillation of other physical components. Among the most important characteristics of the Arctic are reduced light, seasonal darkness, prolonged low temperature and icy period, which result in impoverished fauna and flora and low seasonal productivity. Contrary to habitats of lower latitudes, including coral reefs, where biodiversity is, generally, inversely proportional to the respective biomass of each species present, the Arctic is characterized by the dominance of a few species both in abundance and biomass.
Supralittoral, Littoral, and Sublittoral Zones
A bar of coarse sediment can form by waves or ice scouring on certain Arctic shores of Alaska and Canada. Pools of brackish water and typical marsh vegetation, including Carex spp., Pucinellia, mats of mosses, blue-green algae and diatoms, often occur behind these beaches. These supralittoral Arctic marshes can sustain populations of cladocerans, copepods, branchio-pods, dipteran larvae and oligochaete worms, numerous insects, shorebirds, and caribou herds (Broad 1982).
The intertidal and shallow subtidal areas are relatively barren, at least on the surface. For instance, the Arctic coasts of Alaska and western Canada have no littoral flora and only sparse vegetation in the supralittoral (Broad 1982). The virtual absence of intertidal fauna, which results in the absence of a fauna in the upper littoral zone, may be attributed to the freezing air and low humidity. However, the barrenness is usually explained, according to many authors, by the mechanical action of ice on the shores and/or to the weak tidal amplitude itself.
When wind, current, and tide drive ice floes against the shore, bottom sediments, rocks, and benthic fauna and flora are mixed, overturned, and ground together. The resulting clouds of mud may extinguish the life of nearby organisms under a blanket of mud and smother filter-feeders hundreds of meters away. Consequently, when they are present in the Arctic, the intertidal species found in the Atlantic or Pacific are usually located in the subtidal area.
While sparse, the littoral fauna of the High Arctic is characteristic. In Alaska, the shore to a depth of about 2 m, the approximate depth of seasonal ice, is probably colonized by less than 50 species of macrobenthos, mainly oligochaete worms, midge larvae, amphipods (Gammarus setosus and Onisimus litoralis) and the isopod Saduria entomon, which form nearly the entire biomass (3 ± 5 g m−2; Broad 1982). The sublittoral fauna beyond the depth reached by ice is more diverse, including species such as mysid shrimps (Mysis relicta and Neomysis rayii), polychaete worms (Scolecolepides arcticus, Ampharete vega, Prionospiro cirrifera, Terebellides stroemi and others), bivalve mollusks (Cyrtodaria kurriana and Lyocyma fluctuosa), the priapulid Halicryptus spinulosis, amphipods (Pontoporeia affinis and Calliopus laevuisculus), and the four-horned sculpin Myoxocephalus quadricornis (Broad 1982). The boundaries between Arctic and Subarctic shores of northern Canada and Greenland can be determined by the sudden disappearance in the northern parts of three common invertebrates, Mytilus edulis, Littorina saxatilis var. groenlandica, and Balanus balanoides. The last two are the most decisive indicators as their disappearance is more abrupt. In northern Iceland, the littoral zone is characterized by the succession of different species of Fucus, from Fucus spiralis in the upper section to Fucus edentatus in the lower littoral (Munda 1991).
The sublittoral of Alaskan shores harbors benthic macroalgae, including three species of Chlorophyta, which infrequently grow in the littoral zone, 14 species of Phaeophyta and 11 species of Rhodophyta. The intertidal and subtidal zones are feeding grounds for about 30 species of fish, including anadromous salmonids, typically marine gadids, pleuronectids, cottids and a few freshwater species (Broad 1982).
The Arctic shores of eastern Greenland are similar to those of Alaska. A few algae occur on rocks with Fucus inflata in the lower littoral. The fauna of the littoral consists of mostly oligochaete worms (Enchytreaus albidus and Lumbricetta lineatus), mites (Molgus littoralis and Ameronothrus lineatus) and sublittoral crustaceans (Gammarus wilkitzkii and Mysis oculata) (Broad 1982). Warm currents along some coasts of Norway, Iceland, Greenland, and other regions of the Barents and Norwegian Seas promote the occurrence of a boreal biota along Arctic shores. In such environments, the most common species of the mid-littoral and continuing subtidal are the blue mussel M. edulis, the gastropods L. saxatilis, with some Buccinum groenlandicum, Margarita helcina and crustaceans of the genera Balanus, Gammarus, Caprella and Ischyrocerus. Some species, such as the polychaete worm Spirorbis spirium and certain gastropods also colonize floating thallus of Fucus and other macroalgae. Jorgensen et al. (1999) indicated that 387 species were observed in the Kara Sea, Arctic Russia, with predominance for polychaetes, crustaceans and mollusks. Boreal-Arctic species clearly dominate this area. The sedimentation rate, as well as depth, sediment structure, and salinity apparently influence the faunal distribution.
Studies performed in southern Baffin Island indicated that numerous pelagic and benthic invertebrates were found below ice-covered sea. The fauna and flora in the long lasting ice cover, the small tides and the reduced wave action allow fine sediments to settle and produce low oxygen concentrations near the bottom. The brittle star Ophiura sarsi, shrimp Sclerocrangon boreas, sea cucumber Chiridota laevis, starfish Crossater papposus and Leptasterias groenlandicus are observed commonly. Rocks deposited by ice and human artifacts provide a scattered hard substrate, which supports a kelp community of Laminaria and Agarum. Barnacles, ascidians, sea cucumbers, sea anemones, gastropods are also observed abundantly on rocky bottoms.
Bluhm et al. (1998) indicated that the sea urchin Strongylocentrotus pallidus was considered an important part of the benthic standing stock and carbon flux in the northern Barents Sea. Holte and Gulliksen (1998) noted that macrofaunal dominant species in the sediment of the north Norwegian coast were detritivorous and carnivorous polychaetes, and detritivorous bivalves. Sponges, bivalves, polychaetes, and nematodes are common in the Svalbard waters (Strömberg 1989).
Primary Production (Phytoplankton)
The algae that grow on the under-surface of the ice, the phytoplankton and the benthic macroalgae, produce biomass that feeds numerous animals. Together, these plants are called the primary producers. Among them, phytoplankton produces the majority of the edible material, although ice-associated algae are of equal importance in some areas (see “Sub-Ice Flora and Fauna”section below).
The onset of ice cover and the loss of winter solar radiation have the clearest impact on the primary production in the Arctic. Although, the level of incident radiation in the polar summer is high, much of it is lost by the high reflectivity from the snow and ice. This restricts the production and leads to extreme seasonal oscillation in both phytoplankton and herbivorous zooplankton. The onset of seasonal production is clearly linked to the melting of snow from the ice surface and the subsequent melting of the ice. The annual primary production in polar regions varies from one area to another and ranges from 5 to 290 g C m−2 (Sakshaug 1989). Blooms are formed mainly in spring or summer when nutrient supply is adequate and vertical mixing is restricted to the upper 30–50 m. They are particularly frequent at the ice edge because melting generates water column stability (Alexander 1980). In the northern waters of Iceland, spring growth of phytoplankton begins in late March and culminates during mid-April (Gislason and Astthorsson 1998).
According to Zenkevitch (1963), more than 200 species of phytoplankton are present in the Barents Sea. About 80% are diatoms, 20% are dinoflagellates and flagellates. During winter and early spring, phytoplankton biomass is small (<0.5 mg chlorophyll a m−3) and mainly composed of small flagellates. The spring bloom gives place to the growth of larger groups, such as diatoms and dinoflagellates. During summer, two main composition patterns are found. One is dominated by microfiagellates in the upper oligotrophic layers and diatoms and other large groups dominate the other, in the sub-surface chlorophyll maximum. Toward autumn, the chlorophyll sub-surface maximum tends to disappear and most of the phytoplankton comprises microfiagellates (Loeng 1989).
Small flagellates dominate the first phase of the phytoplankton bloom in ice-covered water. The main spring bloom occurs in the surface layer close to the ice edge and is usually dominated by diatoms, although flagellates can also be abundant. Toward the end of the diatom bloom, the maximum phytoplankton biomass is found at the nutricline, located below the pycnocline. After the bloom, the major part of the diatoms sink out of the euphotic zone (Loeng 1989).
Strömberg (1989) indicated that as the ice melts in the Svalbard waters, a very active pelagic primary and secondary production begins, which follows the ice-edge as it retreats. Horsted (1989) noted that there are generally two maxima of primary production from April and from August to September in Greenland waters.
Sub-Ice Flora and Fauna
Wherever a sufficient amount of light penetrates the ice and enough nutrients are present, ice algae develop. These algae make ice-covered seas unique. The ice-edge phenomena are closely linked to the cry-opelagic organisms. Thus, one of the short food chains is: primary production (ice-algae, phytoplankton), sea ice amphipods (G. wilkitzkii, Apherusa glacialis), polar cod (Boreogadus saida), sea birds, or mammals. The biomass of the cryopelagic fauna is high close to the ice-edge and decreases with increasing distance from it.
Daily and seasonal melting and formation of the ice has a thermostatic effect, so that the temperature of the water immediately below the ice is almost constant. It is also often of low salinity, hence the ice biota have evolved as euryhaline and stenothermal organisms. Mel’nikov (1980) distinguishes an endemic or autochthonous flora, consisting of Chlorophyta and Cyanophyta, present year-round and developing each spring in the snow above the ice and gradually leaching downward through the ice; and a non-endemic flora dominated by diatoms. This latter flora develops at the bottom of the ice, is planktonic in origin, and is carried upward as the ice thickens in the fall. He indicated that when diatoms die, they become a source of food for the endemic species of flora. The associated fauna is endemic, G. wilkitzkii, Mysis polaris, Derjugina tolli, Tisbe furcata among others, or non-endemic.
The brown zone forming the bottom layer of sea ice is dominated by pennate diatoms, but contains other algae and several species of small invertebrates. Chlorophyll measurements in Arctic Canada show that production of the ice diatoms peaks in mid-June before the phytoplankton blooms in the water below the ice, at a time when the sea ice is still snow-covered (Mansfield 1975). As soon as the snow melts this ice flora disappears, suggesting that it is adapted to low light intensities. It extends the season of production by preceding the normal phytoplanktonic bloom. These algae also provide a source of food for benthos and fish in coastal waters, especially with the cods B. saida and Arctogadus glacialis (Mansfield 1975).
Werner and Arbizu (1999) noted that the lower part of the ice in the Laptev Sea, northern Russia, showed an accumulation of organic matter, mainly composed of organic carbon and chlorophyll, that could provide a food source to the fauna living below the ice in the pelagic habitat, and to the underlying benthos. In fact, they found that large quantities of nauplii, copepods, foraminifers and pteropods were common. Poltermann (1998) found that the Franz Josef Land islands sea ice was inhabited by several amphipods species. Abundance, biomass and small-scale distribution of these cryopelagic amphipods reached 420 ind m−2. Amphipods were concentrated at the edges of the ice floes and were less frequent in areas further away under the ice. Species such as G. wilkitkzii were dominant with the less abundant Apherusa glacialis, Onisimus nanseni, and Onisimus glacialis.
Secondary Production (Zooplankton)
Water near the surface of the Arctic Ocean supports the greatest summer biomass of zooplankton, the abundance generally decreasing with increasing depth. At least 158 species of zooplankton are known to be found in the central Arctic and adjacent seas including Kara, Laptev, East Siberian, and Beaufort. Crustacea, Ctenophora, Molluska, Annelida, Ostracoda, and Chaetognatha are the most common (Grainger 1989).
Like phytoplankton, zooplankton shows an extreme annual oscillation in Arctic Canada. This is mainly due to the increase in populations of the herbivorous species, particularly copepods, which are the dominant species. As phytoplankton grows, copepods grow and reproduce, and then as their food supply comes to an end, they gradually die off. In contrast, the primarily carnivorous zooplankton species show relatively little change in numbers throughout the year and no particular period of reproduction (Mansfield 1975).
Gislason and Astthorsson (1998) indicated that the seasonal variation in biomass and abundance of zooplankton in the waters north of Iceland were low during the winter and peaked once during spring in late May. The principal constituents were Calanus finmarchicus, Pseudocalanus spp., Metridia longa, C. hyperboreus, chaetognaths and euphausid larvae. Kosobokova et al. (1997) studied the composition and distribution of zooplankton in the Laptev Sea where total biomass ranged between 0.1 and 7.9 g m−2. The dominant species were Calanus glacialis, Calanus hyperboreus, and M. longa. Copepods are also the most important grazers in the Barents Sea with ca. 38 species, C. glacialis, C. finmarchicus, and C. hyperboreus being among the most common (Loeng 1989). Euphausids as Thysanoessa spp. are the most important grazers. Among carnivorous zooplankton species, the chaetognaths Sagitta elegans and Eukrohnia hamata, together with ctenophores are considered to be important (Loeng 1989).
Dunbar (1989) and Grainger (1989) pointed out that diel vertical migration of zooplankton in the Arctic Ocean is rare, but seasonal vertical migration is fairly common. In the Barents Sea, larger zooplankton species, such as C. glacialis, are thought to overwinter in deeper layers, returning to the surface layer in early spring to mature and spawn. Spawning takes place during the diatom bloom and the new generation feeds on the remnants of this bloom and subsequent production of phytoplankton. Zooplankton in turn is preyed on by capelin, which during summer has a northward feeding migration (Loeng 1989).
Zenkevitch (1963) characterized the Svalbard water area in the same way as the Barents Sea, with a dominance of copepods C. finmarchicus making up 90% of the zooplankton biomass. The plankton biomass was reported to decrease in a northerly and easterly direction. In the area north of Svalbard, chaetognaths, ctenophores, and amphipods comprise most of the remaining biomass (Strömberg 1989).
Horsted (1989) observed that zooplankton biomass in Greenland waters had its maximum in July at the same time as the second maximum of primary production, while macroplankton had a somewhat longer lasting maximum from June–July onward. Thus, the newly hatched cod larvae seem to depend heavily upon the availability of naupliar and copepodid stages of C. finmarchicus.
In the Arctic, there are ice-free areas in the proximity of completely ice-covered regions, so called polynyas. The correlation between areas of open water in ice-covered Arctic and increased biological productivity is clear (Bazely and Jefferies 1997; Stirling 1997).
Polynyas form where warm, upwelling sea currents prevent the water surface from freezing. They are either small and temporary or extensive and free of ice all winter. The largest ones appear at the same place every year. The biggest of all polynyas is located at the head of Baffin Bay, Canada, and can reach a surface area as large as Lake Superior. In the desert of floating ice, polynyas represent a rich feeding ground and ideal habitat for many tiny plants and animals at the base of the food web. They also represent a temperate environment that enhances survival of Arctic animals. For instance, the ice around polynyas is ideal for the growth of ice algae. Owing to this large amount of food, countless amphipods and larger crustaceans, squids, fishes and mammals can be observed. Ice algae develop soon in spring, as soon as the sun rises high enough to promote minimum photosynthesis, long before the weather begins to warm up. This early start of primary production and its effect on other levels of the food chain is important for seabirds that need time to build up their strength before they can lay their eggs. Moreover, since seabirds can only hunt for food in open water, they are largely dependent upon polynyas. Among them are fulmars, murres, guillemots, and gulls. Marine mammals such as whales, seals, polar bears, and walruses also converge at polynyas to take opportunity of the abundance of food. If no patches of open water existed in the winter pack ice, many animals could not survive.
There are no schooling pelagic fish, though the cryopelagic Atlantic cod (Gadus morhua) is known to occur in large numbers during the spring period in the Barents Sea, and the polar cod (B. saida) appears to form scattering layers. The giant among benthic fish is the Greenland shark (Somniosus microcephalus) long known for its scavenging behavior largely oriented on whale carcasses. Where the Bering Sea intrudes into the Beaufort Sea, abundant pelagic herrings (Clupea harengus) and capelins (Mallotus villosus) occur in the region of the Mackenzie delta. Demersal species such as the Arctic and starry flounders (Liopsetta glacialis and Platichthys stellatus) and the Greenland and saffron cods (Gadus ogac and Eleginus gracialis) are also common. Similarities exist in the southern part of Baffin Island where the Atlantic cod and several deepwater forms like the Greenland halibut (Reinhardtius hippoglossoides) and the rock and roughhead grenadiers (Coryphaenoides rupestris and Macrourus berglax) are observed. The Barents Sea is a feeding ground and nursery for large commercially important fish stocks such as Arctic cods, herrings, Greenland halibuts, haddocks, capelins, redfish, and saithes (Loeng 1989).
Arctic fish must be able to live under conditions of reduced light and in total darkness. Air breathing predators, except for certain seal species, are displaced to gaps, leads and polynyas through interference with respiration. Ice also reduces avian predation to practically zero. In these conditions, ice may be considered advantageous for fish. Moreover, a new biological habitat that might be described as an inverted benthos is provided by ice for fish. A distinct phytoplankton flora occurs immediately below the ice and an abundant crustacean fauna may be tributary to this food source. This diatom-crustaceans community is an important one that supports the Arctic cod, which helps to sustain Arctic char, birds, seals, and belugas.
About 12 species of birds are known to live all year round in the Arctic, including the raven, gyrfalcon, willow and rock ptarmigans, snowy owl, redpoll, Ross’s and ivory gulls, thick-billed murre, dovekie and the black guillemot. Most of them shift south slightly during the Arctic winter. All other birds, about 90 species, are migrants. Numerous species of birds nest in the Arctic, such as the fulmar Fulmarus glacialis and the kittiwake Rissa tridactyla. In the Greenland Sea, the most abundant species are the fulmar, little auk Alle alle, guillemot Uria lomvia, and kittiwake (Mehlum 1997). The abundance of organisms that bloom during summer, including insect larvae, mollusks and crustaceans, are a substantial source of food. Lack of food rather than the cold itself is what makes the Arctic so inhospitable for birds in winter. Nevertheless, considering that the cold is fierce, some of the permanent residents have evolved special adaptation to cope with it.
The generally scattered distribution of marine fish in Arctic waters has not prevented mammals from attaining a dominant position among the marine vertebrates, for they depend mainly on the larger invertebrates, both planktonic and benthic, for their food. Thus, most common mammals of the Arctic are either part of or dependent upon coastal ecosystems. They include polar bear, arctic foxes, wolverines, reindeer, musk oxen, lemmings, and many species of marine mammals.
Five species of seals spend at least part of the year in the Arctic. The bearded seal (Erignathus barbatus) and ringed seal (Pusa hispida) remain all year round. The others are the harp seal, hooded seal, and harbor seal. Except for the harbor seal, all species give birth to their pups on the ice. Most seals are important predators of benthic invertebrates and fish. The most thoroughly investigated species has been the ringed seal, the most truly Arctic of all the mammals. This species is able to survive under the winter fast ice by keeping open breathing holes. In spring, the pup is born in a cavern among rafted ice blocks or on the surface of the ice in a lair excavated in the overlying snow. Predation by the polar bear (Ursus maritimus) and Arctic fox (Alopex lagopus) can cause very high mortality of young in certain areas. In fact, the polar bears feed almost exclusively on seals. The ability of ringed seals to live under fast ice is not shared by any other Arctic pinnipeds, though the bearded seal is known to keep breathing holes in some areas.
Walrus (Odobenus rosmarus) live in the Arctic waters east of Somerset Island, notably in Baffin Bay, Davis Strait and Foxe Basin. Pacific walrus are found along the coast of Alaska and westward along the Arctic shores of Siberia. Walrus give birth on ice floes and, when not feeding, spend most of their time lolling on the ice floes in great numbers. Most of them are bottom feeders grazing on clams and others bivalves in shallow waters. They also eat whelks, sea cucumbers, and other benthic invertebrates.
Four species of whales may be encountered in Arctic waters. Three of them, the bowhead whale (Balaena mysticetus), beluga (Delphinapterus leucas), and narwhal (Monodon monoceros) are permanent residents. Like the walrus, narwhals and belugas are gregarious. Narwhals are found in large herds in the fjords of eastern and northern Baffin Island, Devon Island and Ellesmere Island. These whales occur in the High Arctic waters of the northern hemisphere, where they occupy the most northerly habitat of any cetacean species. The fourth whale species, encountered in summer, is the killer whale (Orcinus orca). Other species, such as right, gray, blue, fin, minke, and humpback whales move to the Arctic during their normal annual migration cycles (Gambell 1989). Toothed whales like sperm, Baird’s beaked, northern bottlenose, long-finned pilot, and beaked whales, among others, can also be observed in the Arctic.
The bowhead whale is the only plankton eater, its diet is focused on euphausids. The beluga and narwhal mostly prey on fish and squids as well as pelagic and benthic invertebrates. Killer whales largely prey on other marine mammals.
The native people of the Arctic are at the top of the food chain and harvest fish, birds, and marine and terrestrial mammals. Inuits have their homeland stretched from the northern tip of Russia across Alaska and northern Canada to parts of Greenland, but their populations remain sparse.
In spite of its remoteness, the Arctic is threatened by airborne pollutants spreading from industrial areas in the lower latitudes, by growing mineral exploitations (coal, nickel, uranium, tin, gold) and also by natural gas and petroleum industries. As a result, Arctic ecosystems and Inuit populations are seriously endangered.
Moreover, during the course of the past century, there has been an overall increase in global temperature of some 0.5 °C. The past decade has been the warmest of the past 100 years with the five warmest individual years having been recorded during it. The recent trends observed are generally consistent with those projected by the global circulation models under increased atmospheric CO2 concentrations (Maxwell 1997). Higher temperature is generally associated with less sea ice and snow cover extent. Thus, global warming could be one of the most important factors affecting the biodiversity, distribution, abundance, and seasonal cycles of Arctic species in the future.
- Bazely DR, Jefferies RL (1997) Trophic interactions in arctic ecosystems and the occurrence of a terrestrial trophic cascade. In: Woodin SJ, Marquiss M (eds) Ecology of Arctic environments. Special publication no. 13 of the British Ecological Society. Cambridge University Press, Cambridge, pp 183–207Google Scholar
- Broad AC (1982) Arctic, coastal ecology. In: Schwartz ML (ed) The encyclopedia of beaches and coastal environments. Hutchinson Ross, Stroudsburg, pp 55–57Google Scholar
- Dunbar MJ (1989) The Arctic Ocean as a biological environment. In: Proceedings of the sixth conference of the Comité Arctique international. E.J. Brill, Leiden, pp 35–47Google Scholar
- Gambell R (1989) Status of the cetaceans populations of the Arctic and Subarctic Seas. In: Proceedings of the sixth conference of the Comité Arctique international. E.J. Brill, Leiden, pp 207–251Google Scholar
- Grainger EH (1989) Vertical distribution of zooplankton in the Central Arctic Ocean. In: Proceedings of the sixth conference of the Comité Arctique international. E.J. Brill, Leiden, pp 48–60Google Scholar
- Horsted SA (1989) Some features of oceanographic and biological conditions in Greenland waters. In: Proceedings of the sixth conference of the Comité Arctique international. E.J. Brill, Leiden, pp 456–476Google Scholar
- Loeng H (1989) Ecological features of the Barents Sea. In: Proceedings of the sixth conference of the Comité Arctique international. E.J. Brill, Leiden, pp 327–365Google Scholar
- Mansfield AW (1975) Marine ecology in Arctic Canada. In: Circumpolar conference on Northern ecology. Ottawa, National Research Council of Canada pp 29–47Google Scholar
- Mel’nikov IA (1980) The ecosystem of Arctic Pack Ice. Biol. Tsentral’nogo Akticheskogo Basseina, Transl. Dept. Sec. Can. Fisheries and Oceans Canada, Arctic Biological Station, CanadaGoogle Scholar
- Menzies RJ (1975) Origin and evolution of the Arctic marine ecosystem. In: Circumpolar conference on Northern ecology. Ottawa, National Research Council of Canada pp 15–25Google Scholar
- Munda IM (1991) Shoreline ecology in Iceland, with special emphasis on the benthic algal vegetation. In: Mathieson AC, Nienhuis PH (eds) Intertidal and littoral ecosystems. Ecosystems of the world, vol 24. Elsevier, Amsterdam, pp 67–81Google Scholar
- Sakshaug E (1989) The physiological ecology of polar phytoplankton. In: Proceedings of the sixth conference of the Comité Arctique International. E.J. Brill, Leiden, pp 61–89Google Scholar
- Strömberg J-O (1989) Northern Svalbard waters. In: Proceedings of the sixth conference of the Comité Arctique International. E.J. Brill, Leiden, pp 402–425Google Scholar
- Zenkevitch L (1963) Biology of the seas of the USSR. Wiley Interscience, New YorkGoogle Scholar