Arctic Ocean

The Arctic Ocean, the smallest of the world's oceans with an area of 12,257,000 square kilometers, lies entirely within the Arctic Circle. Large segments of it remain frozen throughout the year. It has an average depth of 1,000 meters, but, in some parts, is nearly 5,500 meters deep.

Location of the Arctic Ocean

Lying wholly within the Arctic Circle, the Arctic Ocean was once viewed by geographers as a part of the Atlantic Ocean. It is now generally viewed as a discrete body of water with definite boundaries. As such, it is the fourth-largest ocean on Earth, smaller than the Pacific, the Atlantic, and the Indian Oceans, respectively, the largest, second-largest, and third-largest oceans in the world. Waters from all oceans intermingle as tides and currents carry them along and disperse them. The Arctic Ocean is unique in that it is almost landlocked. Essentially circular, it extends from the North Pole south to about 80 degrees north latitude or, if one includes its smaller fringe seas, to about 70 degrees north latitude. The main landmasses it touches are Canada, Alaska, Siberia, Greenland, Iceland, and Norway.

The Arctic Ocean spills about 60 percent of its water into the Atlantic Ocean between Greenland and Spitsbergen, a group of islands that belong to Norway. It is largely the surface waters that are exchanged because of a high range of submerged mountains known as the Faeroe-Icelandic Ridge, which, in some places, breaks the surface and creates islands, blocking the exchange of the deepest water. Of all the major oceans, the Arctic probably has the most independent existence because of its unique pattern of temperatures, currents, and ice conditions. There is virtually no flow of water from the Arctic Ocean into the Pacific because land barriers and Earth's rotation prevent such a flow. Some 35 percent of the water from the Arctic Ocean flows from the Pacific. Most of the other water that enters it comes from the Norwegian Sea.

Crucial to the ecology of the Arctic Ocean is the Greenland Sea. Several large rivers flow from Canada and Siberia into the sea, bringing enormous quantities of water into its somewhat constricted basin. In this part of the world, evaporation is not great, so if the water that comes into the ocean were not expelled into the Greenland Sea, serious problems would ensue.

The water from the Greenland Sea creates a cold current, termed the East Greenland Current, that flows south along Greenland's east coast. The much weaker Labrador Current flows through Smith Sound and Baffin Bay. Yet another weak current flows from the Bering Strait. Water that does not flow out through the Greenland Sea is deflected by Greenland's northern shore. It forms a current that, off the northwest portion of the Arctic Archipelago, runs southwest and west, then turns again, seeking an outlet, which creates a unique circular current in the Arctic Ocean.

This current explains why the part of the Arctic Ocean bordering Siberia has less ice than the same ocean has in Greenland and parts of the Arctic Archipelago, notably Ellesmere Island. Large ice floes tend to drift southward and westward, many of them melting before they can drift into the Atlantic Ocean's congested shipping lanes. Icebergs that reach the Atlantic Ocean are usually brought there by the Labrador Current from western Greenland's fjords. Although some ice melts as it moves southward, the polar ice cap that covers part of the Arctic Ocean has not fully melted in recorded history. However, climate change poses a threat to this stability.

It was once thought that the Arctic Ocean had a considerable effect on the climate and ecology of all the other oceans. Researchers, however, have questioned this supposition, concluding generally that the Arctic Ocean is more affected by conditions in the world's other oceans than they are affected by conditions in the Arctic Ocean.

Extent of the Arctic Ocean

The Arctic Ocean covers an area of more than 12 million square kilometers, about one-seventh the size of the Atlantic Ocean. Many scientists believe global climate change will gradually increase its size and cause flooding in the land areas that touch it.

Several seas lie on the fringes of the Arctic Ocean, including the Barents, Beaufort, East Siberian, Greenland, Kara, and Laptev Seas, as well as Baffin Bay. These fringe seas extend 10 degrees farther south than the Arctic Ocean proper, reaching as far as 70 degrees north latitude. Although some geographers consider the polar regions to be those that cannot sustain the growth of trees, the polar circles that most geographers accept are generally calculated as being 66.33 degrees north and south of the equator, so even the fringe seas are wholly within the Arctic Circle. As global cliamte change progresses, it should be noted that the region that cannot support tree growth is shrinking accordingly, and boreal forest encroaches farther and farther into the northlands.

The whole of the Arctic Ocean is roughly the size of Antarctica, whose ocean is very different from its northern counterpart in that it surrounds a continent, whereas the Arctic Ocean is surrounded by landmasses. That more life thrives in the Arctic than in Antarctica is attributable to the fact that the landmasses around the Arctic Ocean are warmed by the ocean's currents, with much of the water being quite shallow because of the continental shelves. Nevertheless, much of the Arctic Ocean is frozen year-round, with its water temperature hovering between -1.1 and +1 degrees Celsius.

The northern and southern polar regions are generally defined as points on Earth that experience at least one day each year when the sun does not set. This phenomenon is true at both the North and South Poles in June and December of each year, respectively.

Derivation of the Name "Arctic"

In early times, the Arctic Ocean lay in what the ancients called "terra incognita," meaning "unknown land." The areas that it touched were thought to be incapable of sustaining life. However, it is now recognized that the Arctic area is teeming with life of many varieties, from complex vertebrates such as humans, seals, and polar bears to simple microorganisms such as phytoplankton, which flourish in both the Arctic and the Antarctic.

The ancient Greeks named the Arctic after the astronomical constellation "the great bear." The Greek word for bear is arktos—hence "Arctic." The ancients observed that the Great Bear constellation appeared to revolve around the North Pole. Convinced that there must be another pole at Earth's other extremity, the Greeks coined the term "antarktos," or "opposite bear," which in time became the term "Antarctic."

In early times, the Arctic Ocean was often called the Frozen Ocean because so much was permanently covered with ice extending from the polar ice cap. With winter temperatures typically as low as -33 degrees Celsius and below, it was generally thought that the ocean and the area surrounding it precluded human habitation. This fallacy has since been disproved.

Features of the Arctic Ocean

Because much of the Arctic Ocean is frozen year-round, it does not appear like other oceans. At times, the solid icy expanse is not punctuated for hundreds of kilometers by any stretches of open water. Those areas where open water is visible range from dark black to a lighter green, often studded by huge chunks of ice called brash that have splintered off from larger ice floes.

An unusual feature of the Arctic Ocean is the existence of freshwater islands in the surrounding saltwater. This peculiarity is explained by the fact that ice resulting from the freezing of saltwater becomes less and less saline in its constitution as it ages. Ice loses one-half of its salinity in its first year of being frozen; eventually, it reaches the point where it has virtually no salinity so that such ice can be returned to its liquid state and drunk with no ill effects.

If one could look below the surface to the ocean floor, it would present the appearance of a warped, rifted surface with great irregularities. In some places, it sinks to depths of 5,500 meters. Freshwater ice formations, similar to the pingos that mark the Arctic tundra, are present in some shallower water, each moored soundly to the bottom on which they rest.

Beneath its surface, the Arctic Ocean consists of two basins. They are believed to have developed separately more than 100 million years ago when the tectonic plates of Earth's surface drifted apart. The Eurasian Basin resulted when the sea floor spread in a line along the Nansen Cordillera, a range of submerged mountains that constitutes the northernmost part of the Mid-Atlantic Range. In time, this movement pushed a narrow portion of Asia away from the mainland. Known as the Lomonosov Ridge, this sliver lies directly beneath the North Pole. At roughly the same time, the land that is now Alaska moved away from North America and left a basin known as the Canada Basin on the other side of the Lomonosov Ridge. This basin is also sometimes referred to as the Amerasian Basin.

The Arctic Ocean contains the widest continental shelf in the world, between 490 and 1,780 kilometers in width around the Eurasian basin, stretching north from Siberia toward the North Pole. A similar shelf, in the Amerasian Basin, which is from 97 to 200 kilometers wide, extends north from North America. Its exposed portions form the Arctic Archipelago, which consists of Wrangel Island, the Franz Josef Archipelago, the New Siberian and Lyakhov Islands, Severnaya Zemlya, Novaya Zemlya, and Spitsbergen.

The continental shelf that extends north from North America eventually drops off into a deep, oval basin reaching south from the North Pole to the Bering Sea. This and parts of the Greenland Sea east of Greenland are the deepest parts of the Arctic Ocean. It was once thought that no form of life could exist at such depths. However, it has now been established that in some of the deepest parts of the oceans, hot water, sometimes as hot as 367 degrees Celsius, flows out of deeply submerged structures called hydrothermal vents comparable in some ways to volcanoes. Life exists in many forms around such vents.

Cores of ice taken from the Arctic reveal that the area once had a temperate climate. The fossils found in the ice cores suggest that all sorts of vegetation grew where now a wholly different kind of vegetation exists in the harsh climate of the Arctic Circle. Evidence also substantiates the theory that the polar climate is changing again, becoming warmer. This warming has implications for the entire world: if the polar ice caps begin to melt rapidly, low-lying areas of the world may become flooded and uninhabitable. Existing Arctic species, including the iconic polar bears, are also threatened by global climate change and the habitat changes it causes. Climate change has resulted in a loss of permanent sea ice in the Arctic. Studying the Arctic Ocean and the circumpolar regions highlights the fact that everything in nature is connected and that no alteration in nature, whether natural or human-made, is without consequences.

People of the Polar Regions

Despite early conjecture suggesting that the polar regions were uninhabited, it is clear that they have sustained human life for thousands of years. Indeed, various Indigenous peoples continue to make their homelands near the Arctic Ocean, all with specific cultural adaptations to the challenging environmental conditions. These include the Sami (or Saami) of northern Scandinavia and the Yupik and Aleuts of Alaska and far northeastern Russia. Perhaps the best-known to outsiders, however, are the Inuit—a group of distinct but culturally similar peoples in modern Alaska, Canada, and Greenland.

Details of traditional and modern Inuit culture provide insight into how the Arctic environment, including the ocean itself, shapes the cultures of the region's inhabitants. The Inuit are experts at fishing through the sea ice and take much of their food from the Arctic Ocean, particularly in winter when they tend to dwell along the ocean's shore. (Traditionally, many Inuit moved inland to the tundra during the summer.) They also hunt whales on a limited basis, which they once harpooned from "umiaks," large open boats made of animal skins on a wood-and-bone frame. Whales provided the Inuit with oil to fuel their lamps and blubber—the large, fatty layers that preserve the whale's buoyancy and body warmth in the frigid Arctic waters. Eating the blubber helped sustain the Inuit during the long winters. In the present day, Inuit cultural traditions live on, but the traditional weapons and boats have largely given way to their modern counterparts, and snowmobiles now run where dogsleds and snowshoes were once the norm.

During the winter, some Inuit build igloos, domed shelters made from blocks of densely packed snow. Caught out in the open with a storm approaching or simply traveling away from home for an extended period, a skilled person could construct an igloo for shelter in minutes. Sometimes, a hole can be cut in the ice of the igloo's floor to catch fish while remaining protected from the driving winter winds. In the twenty-first century, the vast majority of Inuit live in frame houses in scattered villages throughout the north, and the art of building igloos is becoming a rare skill. Concerted action by tribal elders now seeks to preserve the traditional knowledge and pass it down to younger generations as a right of their heritage.

Only incomplete and inaccurate information was available about the Arctic and its people until the nineteenth century when Western exploration of the region began. Earlier European sailors had reached the region searching for a short route to Asia. Most, however, found the area so forbidding that they turned back. In the 1920s, a now-classic semi-documentary film titled Nanook of the North was shot on location. It provided the first exposure to Inuit culture and the Arctic environment for many in the rest of the world.

Technology has changed the lives of the Inuit and other contemporary peoples of the polar regions. Most now reside in villages that have schools, stores, churches, and medical centers. They live in houses made from imported materials. Such houses usually have an airlock, an area between the door that opens to the outdoors and the second door that opens into the house so that the cold Arctic air does not penetrate the building's interior warmth.

For several reasons, the Arctic Ocean remains vital to the Earth and its people in the twenty-first century. The Arctic Ocean and the surrounding area are essential in regulating the Earth’s climate. Rising temperatures and sea levels in the Arctic Ocean negatively affect the globe. Vast ecosystems full of biodiversity make up the Arctic and support Indigenous peoples. The Arctic Ocean is not just of environmental importance; it is strategic for economic and geopolitical reasons. Oil and natural gas are present in its waters, and global shipping routes sail through them, which have implications for international cooperation between nations. 

Principal Terms

brash: splinters that become detached from ice floes and float in the Arctic Ocean

ice floes: large formations of ice, usually 2.5 to 3.5 meters thick, that float in the waters of the Arctic Ocean

igloo: a temporary Inuit structure made from blocks of dense snow

Inuit: the native dwellers of the northern polar regions, whose name means "the People"; often referred to incorrectly as Eskimos, a word from a more southerly native language

phytoplankton: tiny floating sea plants that are most plentiful in the presence of sunshine and rich nutrients

pingo: a large, stable ice intrusion of the Arctic tundra terrain, appearing as a large, dome-shaped, earth-covered mound with cracks visible at the top, the core being solid ice

salinity: the salt content of such substances as water and food

umiak: a large boat covered with animal skins that the Inuit traditionally used when hunting marine mammals such as seals and whales

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