ARCTIC OCEAN

smallest of the world's oceans, centring approximately on the North Pole. The Arctic Ocean and its marginal seas (the Chukchi, East Siberian, Laptev, Kara, Barents, White, Greenland, and Beaufort; some oceanographers also include the Bering and Norwegian Seas) are the least-known basins and bodies of water in the world ocean owing to their remoteness, hostile weather, and perennial or seasonal ice cover. This is changing, however, because the Arctic may exhibit a strong response to global change and may be capable of initiating dramatic climatic changes through alterations induced in the oceanic thermohaline circulation by its cold, southward-moving currents or through its effects on the global albedo resulting from changes in its total ice cover. Although the Arctic Ocean is by far the smallest of the Earth's oceans, having only a little more than one-sixth the area of the next largest, the Indian Ocean, its area of 5,440,000 square miles (14,090,000 square kilometres) is five times larger than that of the largest sea, the Mediterranean. The deepest sounding obtained in Arctic waters is 18,050 feet (5,502 metres), but the average depth is only 3,240 feet. Distinguished by several unique features, including a cover of perennial ice and almost complete encirclement by the landmasses of North America, Eurasia, and Greenland, the north polar region has been a subject of speculation since the earliest concepts of a spherical Earth. From astronomical observations, the Greeks theorized that north of the Arctic Circle there must be a midnight sun at midsummer and continual darkness at midwinter. The enlightened view was that both the northern and southern polar regions were uninhabitable frozen wastes, whereas the more popular belief was that there was a halcyon land beyond the north wind where the sun always shone and people called Hyperboreans led a peaceful life. Such speculations provided incentives for adventurous men to risk the hazards of severe climate and fear of the unknown to further geographic knowledge and national and personal prosperity. This section describes the Arctic Ocean and its marginal seas, discusses the physical characteristics and origin of the ocean floor, and outlines what is known about its physical oceanography and sea-ice dynamics. smallest of the world's oceans, centring approximately on the North Pole. The Arctic Ocean is almost completely surrounded by the landmasses of Eurasia, North America, and Greenland and is distinguished by a cover of ice. The ocean is divided into two major basins, the Eurasia and the Amerasia, which are separated by the Lomonosov Ridge. Each is further subdividedthe Eurasia into the Fram and Nansen basins, which are separated by the Nansen Cordillera; and the Amerasia into the Makarov and Canada basins, separated by the Alpha Cordillera. The Eurasia Basin was formed by seafloor spreading along the axis of the Nansen Cordillera, which began under the edge of the Asian continent. The origin of the Amerasia Basin is less clear, but it may have opened by rotation of the Arctic-Alaska lithospheric plate away from the North American Plate during the Cretaceous Period (about 144 to 66.4 million years ago). The sediments of the ocean floor show that at least part of the Arctic Ocean was relatively warm prior to 40 million years ago. Several factors make the Arctic's physical, chemical, and biological processes significantly different from those of the adjoining North Atlantic and Pacific oceans. The ice pack reduces the exchange of energy between the ocean and atmosphere by a factor of about 100 and reduces the penetration of sunlight necessary for the photosynthetic processes of marine life. The Arctic Ocean is also distinguished by a high ratio of shallow marginal seas to deep basins; the former occupy about 36 percent of the ocean's surface area but contain only 2 percent of its volume. The major circulation into and from the Arctic Basin is through the Fram Strait, which lies between Svalbard and Greenland. Circulation of this cold water into the Atlantic contributes to the mean temperature of the world ocean and affects the global climate. All Arctic waters are cold, and variations in their density are determined by changes in their salinity. A thin and less dense surface layer of water is separated by a strong density gradient from the main body of water, which is of uniform density. Three major water masses and one lesser mass may be identified. The Arctic water from the surface to a depth of 650 feet (200 m) is the most variable because of the continual freezing and thawing cycle and because of additions of fresh water from rivers and from precipitation. Its temperatures may vary over a range of 7 F (4 C). Warmer Atlantic water underlies this layer to a depth of about 3,000 feet (900 m). This water is gradually cooled to a maximum of about 33 F (91 C). Bottom water extends to the ocean floor; it is somewhat colder but similar in salinity. An inflow of Pacific water of warmer temperature and greater salinity may be observed in the Chukchi Sea, flowing as a wedge between the Arctic and Atlantic waters. Between about 60 N and 75 N the occurrence of sea ice is seasonal; above 75 N it is relatively permanent. As sea ice forms the salt is expelled from it as brine. By the time the sea ice is one year old, it is sufficiently salt-free to be melted for drinking. This salt-free ice is referred to as polar pack and is smooth and pale blue in colour. Younger ice is more jagged and grayer; it has a characteristic thickness of about 6 feet (2 m), whereas older ice averages twice that thickness. Area 4,732,000 square miles (12,257,000 square km); maximum depth 18,050 feet (5,502 m). Additional reading Appealing, broad, and beautifully illustrated surveys of the region are offered in Fred Bruemmer et al., The Arctic World (1985), a descriptive work; and Steven B. Young, To the Arctic: An Introduction to the Far Northern World (1989), a more scholarly guide focusing on natural history. State-of-the-art writing on all aspects of arctic research, of various levels of sophistication, is found in such periodicals as Arctic (quarterly), a journal of the Arctic Institute of North America; Arctic Science, Engineering, and Education Awards (annual), published by the National Science Foundation of the United States; and Polar Record (quarterly). See also The Arctic Ocean, a separate issue of the quarterly Oceanus, vol. 29, no.1 (Spring 1986).For geology and geophysics of the region, see Arthur Grantz, L. Johnson, and J.F. Sweeney (eds.), The Arctic Ocean Region (1990), which examines mainly the geology of the ocean floor and adjoining lands, with discussions of physical environments; Yvonne Herman (ed.), Marine Geology and Oceanography of the Arctic Seas (1974), and The Arctic Seas: Climatology, Oceanography, Geology, and Biology (1989); Burton G. Hurdle (ed.), The Nordic Seas (1986); and H.R. Jackson and G.L. Johnson, Summary of Arctic Geophysics, Journal of Geodynamics 6(14):245262 (1986).Works on oceanography and ice behaviour include K. Aagaard, On the Deep Circulation in the Arctic Ocean, Deep-Sea Research, part A, 28(3A):251268 (March 1981); K. Aagaard and E.C. Carmack, The Role of Sea Ice and Other Fresh Water in the Arctic Circulation, Journal of Geophysical Research 94(C10):1448514498 (October 1989); Arctic Research Advances and Prospects: Proceedings of the Conference of Arctic and Nordic Countries on Coordination of Research in the Arctic, 2 vol. (1990); L.K. Coachman, K. Aagaard, and R.B. Tripp, Bering Strait: The Regional Physical Oceanography (1975); W.D. Hibler, III, and K. Bryan, A Diagnostic Ice-Ocean Model, Journal of Physical Oceanography 17(7):9871015 (July 1987); Sea-Ice and Climate: Report of the Fourth Session of the Working Group on Sea-Ice and Climate (1990), a special publication of the World Meteorological Organization and the International Council of Scientific Unions; G.A. Maykut, Large-Scale Heat Exchange and Ice Production in the Central Arctic, Journal of Geophysical Research 87(C10):79717984 (September 1982); and Norbert Untersteiner, The Geophysics of Sea Ice (1986). Louis Rey (ed.), The Arctic Ocean: The Hydrographic Environment and the Fate of Pollutants (1982), collects papers on the marine pollution in the region. Ned Allen Ostenso Study and exploration The earliest references to Arctic exploration are shrouded in obscurity resulting both from inaccurate ideas of the shape of the Earth and from primitive navigation techniques, which make it difficult to interpret early maps and accounts of voyages. Probably the first to approach the Arctic regions was a Greek, Pytheas, who in the 4th century BC made a voyage from the Mediterranean, around Britain, to a place he called Thule, variously identified as the Shetlands, Iceland, and Norway. The accounts of this remarkable explorer were for centuries discredited, but the idea of Thule, shrouded in fog and believed to be the end of the Earth, caught the imagination of many. Iceland is known to have been visited by Irish monks in the 8th and 9th centuries, but it was the Vikings from Norway who settled the island, late in the 9th century. In the course of the next four centuries, these hardy sailors established trade routes to the White Sea, visited Greenland (c. 982) and founded two settlements on the southwest coast (which disappeared, for unknown reasons, before the 16th century), reached the coast of North America, and probably also reached Svalbard and Novaya Zemlya. Unfortunately, however, they left scant records of their voyages, and many of the places they visited had to be rediscovered by others. The Northeast Passage Routes of major Arctic explorations. English and Dutch exploration of the Eurasian Arctic. After a long period of inactivity following the decline of the Vikings, leadership in Arctic exploration was assumed in the early 16th century by the Dutch and the English. The motive was trade with the Far East. The known sea routes around the southern tips of Africa and South America had been claimed as a monopoly by Portugal and Spain, respectively, and besides were long and arduous; the overland routes were even worse. There remained, however, the northern latitudes, and the attempts of English and Dutch merchants to find a Northeast and Northwest Passage gave a strong stimulus to exploration of the Arctic. In 1553 the English sent three ships to the northeast under the command of Sir Hugh Willoughby, with Richard Chancellor as chief pilot. Willoughby, with two ships, wintered in a harbour on the Kola Peninsula, where he and all his men perished. Chancellor, who in the Edward Bonaventure had become separated from the others in a gale, reached what is now Archangel (Arkhangelsk) and made an overland journey to Moscow (1,500 miles in all) before returning home to England. It is interesting to note that these waters were already well known to Russian sailors, who used the route around North Cape (in Norway) to western Europe as early as 1496, but this was not generally known at the time. After Chancellor's voyage the Muscovy Company was formed, and there grew up a lucrative trade with Russia, the success of which rather distracted the minds of the English from the Northeast Passage. Nevertheless, in 1556 Stephen Borough sailed in the Searchthrift to try to reach the Ob River, but he was stopped by ice and fog at the entrance to the Kara Sea. It was not until 1580 that another English expedition, under Arthur Pet and Charles Jackman, attempted its passage. They too failed to penetrate it, and England lost interest in searching for the Northeast Passage. In the meantime, however, the Dutch had taken up the search, largely because of the efforts of Olivier Brunel, who in 1565 established a trading post at Archangel. In the course of an eventful career, Brunel made an overland journey to the Ob and in 1584 tried to reach it by sea, but like Pet and Jackman he got no farther than Yugorsky Shar Strait. He was followed by Willem Barents, an outstanding seaman and navigator, who in 1594 discovered Novaya Zemlya and sailed to its northern tip. As Barents coasted north, he noted the wreckage of ships and grave markers at many points along the shore, indicating that Russians had been there before him. His two companions, Cornelis Nai and Brant Tetgales, penetrated a little way through Yugorsky Shar Strait into the Kara Sea. In 1596, with Jan Cornelisz Rijp and Jacob van Heemskerck, he was more successful. Heading due north from Norway instead of following the coast around, Barents discovered Bear Island and Svalbard, which he mistook for Greenland. Rijp then went home with one ship, but Barents and Heemskerck in the other headed east and rounded the north of Novaya Zemlya. They were forced to winter in Ice Haven on the northeast coast and thus became the first Europeans known to have wintered successfully in the Arctic. They built a house of driftwood and passed the season with remarkable fortitude and success; there were only two deaths from scurvy. In the spring, the ship being hopelessly damaged, they escaped across the open Barents Sea in two small boats. Barents died on the journey. In 1609 Henry Hudson, the Englishman, sailed in the Half Moon to the Barents Sea in the service of the Dutch East India Company, but his crew, afraid of having to winter like Barents, mutinied and forced him to sail west, where he explored the coast of North America north of Virginia and ascended the Hudson River. The economy The Arctic has been little exploited for economic purposes, but it contains 8 percent of the surface of the planet and 15 percent of the land area, so significant resources, both renewable and nonrenewable, may be reasonably assumed to be present. Some of these are knownand being utilizedbut there could be enormous expansion if it is required and thought desirable. Exploration for mineral resources in particular has been far from exhaustive. Resources Mineral resources At the present time the most important resources are the minerals, especially hydrocarbons. Two of the world's major producing areas for oil and natural gas lie in the Arctic. Northwestern Siberia contains a petroliferous province discovered in the 1950s, stretching 500 miles from east to west and 750 miles from north to south and producing a large proportion of Russia's output of both oil and natural gas. The North Slope of Alaska produces about one-fifth of the U.S. output, but only 11 percent of U.S. consumption. There are smaller exploitations in the Canadian Northwest Territories (oil at Norman Wells) and elsewhere in Russia (oil and natural gas in the Pechora basin and natural gas in Yakutiya). Further large discoveries are likely. Drilling is proceeding offshore, and there are promising areas at many points north of Russia, where the continental shelf is very wide. Outside Russia there has been exploration off Svalbard and off both West and East Greenland, but without success. Successful development of these hydrocarbon resources depends largely on pipeline transport. Both the Siberian and the Alaskan fields are effectively served by this means. Hard-rock mining is also well developed, especially in Russia, where the former Soviet government's desire for national self-sufficiency provided a compelling spur. The major centres are located around Murmansk and Norilsk. The only significant source of diamonds in Russia is in Yakutiya. There is also gold, tin, nickel, copper, platinum, and cobalt, together with iron ore, coal, and apatite. All these are being worked. For the first four, the north provides probably the largest sources in the country. There is some mining in Alaska and Arctic Canada, especially of lead-zinc, but it is not such a significant addition to national resources as in Russia. The people Distribution of Arctic peoples. The Arctic, or circumpolar, peoples are the indigenous inhabitants of the northernmost regions of the world. For the most part, they live beyond the climatic limits of agriculture, drawing a subsistence from hunting, trapping, and fishing or from pastoralism. Thus climatic gradients, rather than simple latitude, determine the effective boundaries of the circumpolar region, and these gradients have their counterparts in the major environmental transitions. Of these transitions, the most important is the tree line, which marks the northern margin of the coniferous forest, or taiga. Between this limit and the coasts of the Arctic Ocean, the land consists of open tundra, though, in regions of high altitude, pockets of tundra lie enclosed within the forest zone. Arctic environments are commonly imagined to be barren and inhospitable, habitable only by virtue of the extreme physical endurance and technical virtuosity of the peoples who dwell in them. Though their possession of these qualities is not in doubt, this view of the far north rests on a misconception. The image of the remote wilderness, to be conquered through a struggle for survival, belongs to the language of the alien explorer, not to that of the native. For indigenous people, the circumpolar environment is neither hostile nor forbidding but familiar and generous, offering the gift of livelihood to those who would treat it with consideration and respect. Though there are indeed seasons of scarcity, these alternate with periods of extraordinary abundance. The continuous daylight of the warm Arctic summer, coupled with ample surface water from melting snow, allows for a phenomenal rate of growth of surface vegetation, and this in turn attracts a multitude of animals, many of them of migratory species. Warm ocean currents around some of the Arctic coasts are likewise conducive to an abundance of marine fauna. It is not, then, scarcity that characterizes the Arctic environment but rather its seasonality. The resources available for human subsistencewhich are primarily faunal rather than vegetabletend to occur in great concentrations at particular times of year, rather than being widely dispersed and continuously available. These fluctuations naturally affect the settlement patterns and movements of human populations, as do the marked seasonal variations in the length of day and night and in the opportunities afforded by the landscape for transport and travel. Adaptations to local environments The three major environmental zones of forest, tundra, and coast, and the transitions between them, establish the range of conditions to which the ways of life of the circumpolar peoples are adapted. These conditions are strikingly uniform across both northern North America and Eurasia, and this uniformity is matched by remarkable similarities in cultural adaptation throughout the circumpolar region. Broadly speaking, it is possible to class these adaptations into four kinds. The first is entirely confined within the forest and is based on the exploitation of its fairly diverse resources of land animals, birds, and fish. Local groups tend to be small and widely scattered, each exploiting a range of territory around a fixed, central location. The second kind of adaptation spans the transition between forest and tundra. It is characterized by a heavy, year-round dependence on herds of reindeer or caribou, whose annual migrations from the forest to the tundra in spring and from the tundra back to the forest in autumn are matched by the lengthy nomadic movements of the associated human groupswhether these be of hunters (as in North America), who aim to intercept the herds on their migrations, or of pastoralists (as in Eurasia), who are in continuous association with them. The third kind of adaptation, most common among Inuit (Eskimo) groups, involves a seasonal movement in the reverse direction, between the hunting of sea mammals on the coast in winter and spring and the hunting of caribou and fishing on the inland tundra in summer and autumn. Fourth, typical of cultures of the northern Pacific coast is an exclusively maritime adaptation. People live year-round in relatively large, coastal settlements, hunting the rich resources of marine mammals from boats in summer and from the ice in winter. The people Peoples and cultures of the western Arctic Distribution of Arctic peoples. The Eskimo (Inuit and Yupiit) and Aleuts are people of the treeless shores and tundra-covered coastal hinterlands of northernmost North America and Greenland and the eastern tip of the Chukchi Peninsula of Siberia. Custom alone designates them Eskimo and Aleuts rather than American Indians like all other native Americans, from whom they are distinguished principally by their language. Physical anthropology Eskimo and Aleuts are of medium height, with large bones and a stocky build, relatively large heads, and broad, flat faces. Despite some expectations, studies provide no clear evidence of a genetic adaptation to the northern climate. Even the elevated basic metabolic rate among Eskimo who follow a traditional way of life has been shown to be the result of the diet (probably the highest in meat and fats of any people in the world) rather than a genetic modificationalthough it is undoubtedly helpful to people who live in cold regions. Eskimo and Aleuts have commonly been classed together as Arctic Mongoloids and have been said to stand apart in physical characteristics from American Indians and also from Asians, except for some peoples of northeastern Siberia. But a separation from other American natives is one of degree only, for physically all American Indians are more closely related to northeastern Asians than to any other of the world's regional human populations. Furthermore, studies of the internal diversity among Eskimo and Aleuts minimize their distinctiveness from other American natives. One of the first characters to be analyzed was head form, where Aleuts differ from Eskimo in that the vault of their cranium is on average much lower. Aleuts also exhibit a change in head shape as one moves from west to east, with relatively long heads (measured front-to-back in the horizontal dimension) found in the western islands and relatively short heads in the east. Similarly, speakers of Inuit (Greenland, Canada, and northern Alaska) have on the average very long heads, with the longest and narrowest in the east, becoming more round as one moves west, and rounder still in moving south through the region of Yupik speech to the North Pacific. Partly for these variations, the early physical anthropologist of the Smithsonian Institution, Ale Hrdlicka (18691943), insisted on classifying the Eskimo-speaking people of the Alaska Peninsula and Kodiak Island, as well as all speakers of Aleut, as non-Eskimo American Indians. Although Hrdlicka's physical classification brought sharp rejoinders, recent studies of inherited characteristics of the teeth place the Yupik-speaking people of Kodiak Island and the Alaska Peninsula with Northwest Coast and Athabascan Indians rather than with Eskimo, and some studies of other skeletal characteristics reveal affinities between Aleuts and certain American Indians. Studies of the frequencies of various genes identified from blood components indicate that, although the Eskimo-Aleuts as a group are indeed some genetic distance removed from many American natives, they are not so distant from others, including the northern Athabascan peoples, who are the Eskimo's immediate neighbours. The people Peoples and cultures of the Eurasian Arctic and subarctic Physical anthropology Distribution of Arctic peoples. The peoples of the Eurasian Arctic and subarctic cannot be placed into clearly demarcated categories in terms of their physical features. There is rather a continuous spectrum of variation, reflecting the many movements of population that have occurred in the region since its initial human settlement in the Paleolithic Period. At the same time, the small size and geographic isolation of many local populations has led to the establishment of often extreme divergences between such populations in the frequencies of particular genes, such as those determining blood groups. Physical anthropologists describe the variation in physical appearance across the region in terms of a gradient between two contrasting racial types, usually designated as European (Caucasoid) and Asiatic (Mongoloid). The original inhabitants of the Siberian north approximated to the latter type, and Asiatic features are shared to some extent by all the indigenous peoples of northern Eurasia. They are most in evidence among the peoples of northeastern Siberia. Moving farther west, Asiatic features become increasingly mixed with European ones. This is shown in such features as lighter skin; smaller, narrower, and less flat face, with a more pointed and protuberant nose; more abundant beard and body hair; and less developed epicanthic fold. Within this overall range of variation, scholars have offered a bewildering variety of alternative taxonomic classifications. Perhaps the simplest distinguishes between Uralian (Uralic), Paleo-Siberian, Central Asian, and Arctic types. In the first, extending to the west of the Yenisey River, European features are most strongly represented. This is above all the case among the Sami, owing to their prolonged and extensive contacts with Finnish and Scandinavian settlers. The Paleo-Siberian type is represented by pre-Russian populations in northern Siberia to the east of the Yenisey, though these populations have been considerably affected in their physical features by the intrusion of Tungusic-speaking groups originating from the more southerly regions of Transbaikal. The Arctic type, whose features are intermediate between those of Asiatic peoples and those of Native American peoples, is common to the Yupik and Inuit populations of both Siberia and Arctic North America, as well as to the coastal groups of Chukchi and Koryak (the inland Chukchi and Koryak remain more Paleo-Siberian in their features). Finally, the Central Asian type, though predominant in southern Siberia and Mongolia, is also represented by the Yakut people, whose northward thrust of colonization along the Lena River led to extensive admixture with indigenous Paleo-Siberian populations. In the present day, of course, physical differences between the indigenous populations of the north have been further diluted by the spread of peoples of European descent throughout the region. Ethnic composition In northern Eurasia there is no division corresponding to that in northern North America between the exclusively tundra- and coastal-dwelling Yupik, Aleut, and Inuit and the Indian groups that dwell partially or wholly within the taiga, or boreal forest. With the exception of the inhabitants of the coastal regions around the Bering Strait (Siberian Yupik and coastal Chukchi and Koryak), the indigenous peoples of northern Eurasia either inhabit the taiga year-round or migrate annually between the taiga margins and the tundra. In that respect they are more comparable to the peoples of the North American subarctic region than to those of the Arctic. Strictly speaking, the Eurasian Arctic region includes only those peoples whose lives and livelihood are principally confined to the tundra; however, for the purposes of this article, a number of other, forest-dwelling groups will be included, which have conventionally fallen within the general rubric of circumpolar peoples. Inevitably, the criteria for inclusion within this category are somewhat arbitrary, but they include a traditional dependence on hunting, trapping, and fishing and/or the herding of reindeer (rather than other domestic livestock) and the absence or relative insignificance of agriculture. In common with circumpolar peoples generally, those of northern Eurasia do not constitute clearly demarcated tribes. Ethnic and territorial boundaries, insofar as they are recognized at all, are ill-defined and fluid. Moreover, the enumeration of ethnic groups is further complicated by the many different names by which these groups may be known. Some names are broadly inclusive, designating populations of tens or even hundreds of thousands, whereas others apply to particular local groups of no more than a few hundred individuals. Some names are indigenous, others are of foreign origin. In many cases, the indigenous designation is simply the term in the local language or dialect meaning person or human being. Bearing in mind these reservations, the following ethnic groups may be distinguished (with one or two exceptions, indigenous names are used throughout; where names of foreign origin have been in common ethnological use, these are placed in parentheses).