Pacific Ocean
The Pacific Ocean, largest of Earth's oceans, is about 15 times larger than the United States and covers more than 30% of Earth's surface. The edges of the Pacific are often called the Ring of Fire because many active volcanoes and earthquakes occur where the ocean plate is moving under the edges of continental plates. The southwestern Pacific is dotted with many islands. Also in the western pacific, the Challenger Deep in the Mariana Trench plunges to 35,827 feet below sea level. Most of the world's fish catch comes from the Pacific, and oil and gas reserves there are an important energy source.
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Atlantic Ocean
Among Earth's great oceans, the Atlantic is second only to the Pacific in size. The floor of the Atlantic is split by the Mid-Atlantic Ridge, which is part of the Mid-Ocean Ridge - the longest mountain chain on Earth. The Atlantic poses many hazards to human activity. Tropical storms called hurricanes form in the warm tropical waters off the west coast of Africa and move across the ocean to bombard the islands of the Caribbean and coastal areas of North America with damaging winds, waves, and rain in the late summer and fall. In the cold waters of the North Atlantic, sea ice and icebergs pose a danger to shipping, especially during winter and spring.
The Atlantic has rich deposits of oil and natural gas, but drilling has resulted in pollution problems. In addition, the Atlantic has important marine fisheries, but over fishing has put some species at risk. Sea lanes between Europe and the Americas are among the most heavily trafficked in the world. |
Indian Ocean
The Indian Ocean stretches from Africa's east coast to the southern coast of Asia and the western coast of Australia. It is the third largest of Earth's great oceans. Changing air pressure systems over the warm waters of the India Ocean trigger South Asia's famous monsoon climate - a weather pattern in which winds reverse directions seasonally. The Bay of Bengal, an arm of the Indian Ocean, experiences devastating tropical storms, similar to hurricanes, but called cyclones in this region. Islands along the eastern edge of the Indian Ocean plate experience earthquakes that sometimes cause destructive ocean waves, called tsunamis.
The Arabian Sea, Persian Gulf, and Red Sea, also extensions of the Indian Ocean, are important sources of oil and natural gas reserves and account for an estimated 40% of the world's offshore oil production. The sea routes of the Indian Ocean connect the Middle East to the rest of the world, carrying much needed energy resources on huge tanker ships. |
Arctic Ocean
The Arctic Ocean lies mostly north of the Arctic Circle, bounded by North America, Europe, and Asia. Unlike the other oceans, the Arctic is subject to persistent cold throughout the year. Also because of its very high latitude, the Arctic experiences winters of perpetual night and summers of continual daylight. Except for coastal margins, the Arctic Ocean is covered by permanent drifting pack ice that averages almost 10 feet in thickness. Some scientists are concerned that the polar ice may be melting due to global warming, putting at risk the habitat of polar bears and other arctic animals.
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