Russia, Canada, Greenland, Iceland, Norway, and the United States (Alaska) border on the Arctic Ocean. There are islands around the ocean's outer edges but none in its central region.

In the center of the Arctic Ocean is an immense area of floating pack ice several hundred miles in diameter. The pack ice moves slowly in a clockwise direction, making a complete revolution around the top of the world every ten years. It consists of countless gigantic islands of ice that crash and grind together as they move. There are many small areas of open water. People and animals regularly travel across the pack ice, but they do so in constant peril from the ice itself and from the region's brutally cold climate.

The pack ice restricts the amount of sunlight that can penetrate to the waters beneath it. This reduces the occurrence of photosynthesis, which is fundamental to plant growth. As a result, few of the microscopic plants called phytoplankton grow beneath the ice cap. Since phytoplankton, directly or indirectly, provide the food for all oceanic life, the number of fishes is also limited. Overall, the Arctic Ocean has less than 10 percent as much marine life as the other oceans. It is a kind of frigid, watery desert.

At the ocean's borders, however, where its waters mix with those of the Atlantic and Pacific, animals thrive. Fishes and birds are numerous. Mammals common to the area include seals, walruses, and the most famous Arctic animal of all—the polar bear.

The major circulation of water into and out of the Arctic Ocean takes place through a single deep channel between Greenland and the Norwegian islands of Svalbord. Only 2 percent of this water leaves the ocean as ice—pieces broken loose from the pack—but this tiny amount creates great problems. The channel is one major source of icebergs in the North Atlantic. Although their movements are constantly monitored by satellites and radar, these huge floating masses of ice have destroyed innumerable ships.

Despite the inroads of modern civilization, many of the native peoples of the Arctic regions still follow their traditional ways of life as reindeer herders (primarily in Eurasia) or hunters. Some Inuit, or Eskimo, live near the edge of the pack ice and spend most of their lives hunting and fishing (see Inuit).

Early European explorers tried to find a Northwest Passage—a sea route through the Arctic Ocean from Europe to the Orient. Modern explorers have conducted climatic and other scientific research (see Polar Exploration).

The discovery of oil, gas, and other minerals in the lands bordering the Arctic Ocean and beneath its floor greatly increased economic activity there after the 1960s. Russia, which has the longest coast on the Arctic Ocean, estimates that 70 percent of its untapped oil resources are located under its northern continental shelf.

Canada, which also has a long Arctic coast, can give only rough estimates of the oil, gas, coal, and other mineral resources in its northernmost territories, but they are thought to be substantial. After finding huge oil reserves on the Arctic coast of Alaska, the United States constructed a pipeline across that state from Prudhoe Bay in the north to the ice-free port of Valdez in the south. The Arctic Ocean floor may someday be mined as well. There are indications that valuable metals may be present.

The increased economic activity in the Arctic Ocean area has caused considerable environmental concern. Habitats and living patterns of wildlife and sea life have been disturbed. The potential dangers from oil spills and other forms of pollution are immense. The Arctic ecosystem is fragile, with comparatively few species; therefore any disruption has far-reaching effects. Because of the harsh Arctic cold, many areas that border the pack ice are open for shipping and construction of drilling platforms for only a few weeks each year. When this “summer” season is over, the ocean freezes and becomes impassable. This raises the danger that an oil leak might continue for months before it could be stopped and the spill cleaned up. Also, in the frigid Arctic climate, the rate at which crude petroleum and other pollutants decompose into environmentally harmless components is extremely slow. The effects of such pollution on wildlife and sea life could be catastrophic.

So far the Arctic Ocean has survived increased human activity. Scientists are seeking ways to exploit its abundant resources without damaging the fragile environment. (See also Arctic Regions.)