Oceans

Image by Saperaud [GFDL (http://www.gnu.org/copyleft/fdl.html) or CC-BY-SA-3.0 (http://www.creativecommons.org/licenses/by-sa/3.0/)], via Wikimedia Commons

Excerpt below copied from McGranahan, Balk and Anderson (2007).

Approximately 71% of the Earth’s surface is covered by oceans, including the Arctic, Atlantic, Indian, Pacific, and Southern Ocean. There are many social, economic, cultural as well as environmental reasons to pay careful attention to the world’s oceans. Oceans are vital to sustaining life on earth, they are home to abundant biodiversity, they play a crucial role in climate systems, they enable global commercial transport of goods,  and they generate billions of dollars in revenue and jobs each year.  Concerns about sea level rise is another important factor. An estimated 1 out of every 10 people on earth live in vulnerable coastal regions with low elevations — less than 30 feet above sea level. These low-elevation areas are home to 634 million people. The 10 countries with the most people in the low coastal areas are China, India, Bangladesh, Vietnam, Indonesia, Japan, Egypt, United States, Thailand, and the Philippines. Two-thirds of world’s largest cities (urban areas with 5 million or more people) lie, at least partly, in these coastal areas with low elevation.

Source: McGranahan, Gordon, Deborah Balk, and Bridget Anderson. 2007. “The rising tide: assessing the risks of climate change and human settlements in low elevation coastal zones.” Environment and Urbanization 19:17-37.

The world’s oceans are actually one interconnected body of salt water. As a whole this body of salt water is referred to as the World Ocean or global ocean (“Ocean”. The Columbia Encyclopedia. 2002. New York: Columbia University Press; “Distribution of land and water on the planet”. UN Atlas of the Oceans).

The major oceanic divisions are defined in part by the continents, various archipelagos, and other criteria. These divisions are (in descending order of size):

• Pacific Ocean, which separates Asia and Australia from the Americas
• Atlantic Ocean, which separates the Americas from Eurasia and Africa
• Indian Ocean, which washes upon southern Asia and separates Africa and Australia
• Southern Ocean, sometimes subsumed as the southern portions of the Pacific, Atlantic, and Indian Oceans, which encircles Antarctica and covers much of the Antarctic
• Arctic Ocean, sometimes considered a sea of the Atlantic, which covers much of the Arctic and washes upon northern North America and Eurasia

The Pacific and Atlantic may be further subdivided by the equator into northern and southern portions. Smaller regions of the oceans are called seas, gulfs, bays, straits and other names.
Source: Wikipedia: http://en.wikipedia.org/wiki/Ocean viewe,d 12/21/09