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Rotating series of maps showing alternate divisions of the oceans
Maps exhibiting the world's oceanic waters. A continuous body of water encircling the Earth, the world (global) ocean is divided into a number of principal areas. Five oceanic divisions are usually recognized: Pacific, Atlantic, Indian, Arctic, and Southern; the last two listed are sometimes consolidated into the first three.
Earth's oceans
(World Ocean)
An ocean (from Greek Ωκεανός, Okeanos (Oceanus)) is a major body of saline water, and a principal component of the hydrosphere. Approximately 71% of the Earth's surface (~3.61 X 1014 m2) is covered by ocean, a continuous body of water that is customarily divided into several principal oceans and smaller seas.
More than half of this area is over 3,000 metres (9,800 ft) deep. Average oceanic salinity is around 35 parts per thousand (ppt) (3.5%), and nearly all seawater has a salinity in the range of 30 to 38 ppt. Scientists estimate that 230,000 marine life forms of all types are currently known, but the total could be up to 10 times that number.[1]

Contents

Overview

Though generally described as several 'separate' oceans, these waters comprise one global, interconnected body of salt water often referred to as the World Ocean or global ocean.[2][3] This concept of a continuous body of water with relatively free interchange among its parts is of fundamental importance to oceanography.[4]
The major oceanic divisions are defined in part by the continents, various archipelagos, and other criteria. These divisions are (in descending order of size):
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.
Geologically, an ocean is an area of oceanic crust covered by water. Oceanic crust is the thin layer of solidified volcanic basalt that covers the Earth's mantle. Continental crust is thicker but less dense. From this perspective, the earth has three oceans: the World Ocean, the Caspian Sea, and Black Sea. The latter two were formed by the collision of Cimmeria with Laurasia. The Mediterranean Sea is at times a discrete ocean, because tectonic plate movement has repeatedly broken its connection to the World Ocean through the Strait of Gibraltar. The Black Sea is connected to the Mediterranean through the Bosporus, but the Bosporus is a natural canal cut through continental rock some 7,000 years ago, rather than a piece of oceanic sea floor like the Strait of Gibraltar.
Despite their names, smaller landlocked bodies of saltwater that are not connected with the World Ocean, such as the Aral Sea, are actually salt lakes.

Ocean and life

The ocean has a significant effect on the biosphere. Oceanic evaporation, as a phase of the water cycle, is the source of most rainfall, and ocean temperatures determine climate and wind patterns that affect life on land. Life within the ocean evolved 3 billion years prior to life on land. Both the depth and distance from shore strongly influence the amount and kinds of plants and animals that live there.[5]

Physical properties

The area of the World Ocean is 361×106 km2 (139×106 mi2)[6] Its volume is approximately 1.3 billion cubic kilometres (310 million cu mi).[7] This can be thought of as a cube of water with an edge length of 1,111 kilometres (690 mi). Its average depth is 3,790 metres (12,430 ft), and its maximum depth is 10,923 metres (6.787 mi)[6] Nearly half of the world's marine waters are over 3,000 metres (9,800 ft) deep.[3] The vast expanses of deep ocean (anything below 200 metres (660 ft) cover about 66% of the Earth's surface.[8] This does not include seas not connected to the World Ocean, such as the Caspian Sea.
The total mass of the hydrosphere is about 1,400,000,000,000,000,000 metric tons (1.5×1018 short tons) or 1.4×1021 kg, which is about 0.023% of the Earth's total mass. Less than 3% is freshwater; the rest is saltwater, mostly in the ocean.

Color

A common misconception[citation needed] is that the oceans are blue primarily because the sky is blue. In fact, water has a very slight blue color that can only be seen in large volumes. While the sky's reflection does contribute to the blue appearance of the surface, it is not the primary cause.[9] The primary cause is the absorption by the water molecules' nuclei of red photons from the incoming light, the only known example of color in nature resulting from vibrational, rather than electronic, dynamics.[10]

Glow

Sailors and other mariners have reported that the ocean often emits a visible glow, or luminescence, which extends for miles at night. In 2005, scientists announced that for the first time, they had obtained photographic evidence of this glow.[11] It may be caused by bioluminescence.[12][13][14]

Exploration

False color photo
Map of large underwater features. (1995, NOAA)
Ocean travel by boat dates back to prehistoric times, but only in modern times has extensive underwater travel become possible.
The deepest point in the ocean is the Mariana Trench, located in the Pacific Ocean near the Northern Mariana Islands. Its maximum depth has been estimated to be 10,971 metres (35,994 ft) (plus or minus 11 meters; see the Mariana Trench article for discussion of the various estimates of the maximum depth.) The British naval vessel, Challenger II surveyed the trench in 1951 and named the deepest part of the trench, the "Challenger Deep". In 1960, the Trieste successfully reached the bottom of the trench, manned by a crew of two men.
Much of the ocean bottom remains unexplored and unmapped. A global image of many underwater features larger than 10 kilometres (6.2 mi) was created in 1995 based on gravitational distortions of the nearby sea surface.[citation needed]

Regions and depths

Drawing showing divisions according to depth and distance from shore
The major oceanic divisions
Oceanographers divide the ocean into regions depending on physical and biological conditions of these areas. The pelagic zone includes all open ocean regions, and can be divided into further regions categorized by depth and light abundance. The photic zone covers the oceans from surface level to 200 metres down. This is the region where photosynthesis can occur and therefore is the most biodiverse. Since plants require photosynthesis, life found deeper than this must either rely on material sinking from above (see marine snow) or find another energy source; hydrothermal vents are the primary option in what is known as the aphotic zone (depths exceeding 200m). The pelagic part of the photic zone is known as the epipelagic. The pelagic part of the aphotic zone can be further divided into regions that succeed each other vertically according to temperature.
The mesopelagic is the uppermost region. Its lowermost boundary is at a thermocline of 12 °C (Template:Convert/f), which, in the tropics generally lies at 700–1,000 metres (2,300–3,300 ft). Next is the bathypelagic lying between 10-4 °C (Template:Convert/f), typically between 700–1,000 metres (2,300–3,300 ft) and 2,000–4,000 metres (6,600–13,000 ft) Lying along the top of the abyssal plain is the abyssalpelagic, whose lower boundary lies at about 6,000 metres (20,000 ft). The final zone includes the deep trenches, and is known as the hadalpelagic. This lies between 6,000–11,000 metres (20,000–36,000 ft) and is the deepest oceanic zone.
Along with pelagic aphotic zones there are also benthic aphotic zones. These correspond to the three deepest zones of the deep sea. The bathyal zone covers the continental slope down to about 4,000 metres (13,000 ft). The abyssal zone covers the abyssal plains between 4,000 and 6,000 m. Lastly, the hadal zone corresponds to the hadalpelagic zone which is found in the oceanic trenches. The pelagic zone can also be split into two subregions, the neritic zone and the oceanic zone. The neritic encompasses the water mass directly above the continental shelves, while the oceanic zone includes all the completely open water. In contrast, the littoral zone covers the region between low and high tide and represents the transitional area between marine and terrestrial conditions. It is also known as the intertidal zone because it is the area where tide level affects the conditions of the region.

Geology

The ocean floor spreads from mid-ocean ridges where two plates adjoin. Where two plates move towards each other, one plate subducts under another plate (oceanic or continental) leading to an oceanic trench.

Climate effects

World map with colored, directed lines showing how water moves through the oceans. Cold deep water rises and warms in the central Pacific and in the Indian, while warm water sinks and cools near Greenland in the North Atlantic and near Antarctica in the South Atlantic.
A summary of the path of the thermohaline circulation/ Great Ocean Conveyor. Blue paths represent deep-water currents, while red paths represent surface currents
Ocean currents greatly affect the Earth's climate by transferring heat from the tropics to the polar regions, and transferring warm or cold air and precipitation to coastal regions, where winds may carry them inland. Surface heat and freshwater fluxes create global density gradients that drive the thermohaline circulation part of large-scale ocean circulation. It plays an important role in supplying heat to the polar regions, and thus in sea ice regulation. Changes in the thermohaline circulation are thought to have significant impacts on the earth's radiation budget. Insofar as the thermohaline circulation governs the rate at which deep waters reach the surface, it may also significantly influence atmospheric carbon dioxide concentrations.
For a discussion of the possibilities of changes to the thermohaline circulation under global warming, see shutdown of thermohaline circulation.
It is often stated that the thermohaline circulation is the primary reason that the climate Western Europe is so temperate. An alternate hypothesis claims that this is largely incorrect, and that Europe is warm mostly because it lies downwind of an ocean basin, and because atmospheric waves bring warm air north from the subtropics.[15][16]
The Antarctic Circumpolar Current encircles that continent, influencing the area's climate and connecting currents in several oceans.
One of the most dramatic forms of weather occurs over the oceans: tropical cyclones (also called "typhoons" and "hurricanes" depending upon where the system forms).

Biology

Lifeforms native to oceans include:

Economy

The oceans are essential to transportation: most of the world's goods move by ship between the world's seaports.
Oceans are also the major supply source for the fishing industry. Some of these are shrimp, fish, crabs and lobster.

Ancient oceans

Diagram showing three stages of oceanic evolution, including rift valley, new ocean basin, and mature ocean with sediment and evolving ridge
Genesis of an ocean
Continental drift continually reconfigures the oceans, joining and splitting bodies of water.[citation needed] Ancient oceans include:

Extraterrestrial oceans

See also Extraterrestrial liquid water
Earth is the only known planet with liquid water on its surface and is certainly the only one in our own solar system. However, liquid water is thought to be present under the surface of the Galilean moons Europa and, with less certainty, Callisto and Ganymede. Geysers have been found on Saturn's moon Enceladus, though these may not involve bodies of liquid water. Other icy moons may have once had internal oceans that have now frozen, such as Triton. The planets Uranus and Neptune may also possess large oceans of liquid water under their thick atmospheres, though their internal structure is not well understood.
There is currently much debate over whether Mars once had an ocean in its northern hemisphere, and over what happened to it; recent findings by the Mars Exploration Rover mission indicate Mars had long-term standing water in at least one location, but its extent is not known.
Astronomers believe that Venus had liquid water and perhaps oceans in its very early history. If they existed, all later vanished via resurfacing.
Liquid hydrocarbons are thought to be present on the surface of Titan, though lakes may be a more accurate term. The Cassini-Huygens space mission initially discovered only what appeared to be dry lakebeds and empty river channels, suggesting that Titan had lost what surface liquids it might have had. Cassini's more recent fly-by of Titan offers radar images that strongly suggest hydrocarbon lakes near the colder polar regions. Titan is thought to have a subterranean water ocean under the ice and hydrocarbon mix that forms its outer crust.
Beyond the solar system, the planet Gliese 581 c is at the right distance from its sun to support liquid surface water. However, its greenhouse effect would make it too hot for oceans to exist on the surface. On Gliese 581 d the greenhouse effect may bring temperatures suitable for surface oceans. Astronomers dispute whether HD 209458 b has water vapour in its atmosphere. Gliese 436 b is believed to have "hot ice." Neither of these planets are cool enough for liquid water—but if water molecules exist there, they are also likely to be found on planets at a suitable temperature.[17] GJ 1214 b, detected by transit, found evidence that this planet has oceans made of exotic form of ice VII, making up 75% of all the planet's mass.[18]

Culture

The original concept of "ocean" goes back to notions of Mesopotamian and Indo-European mythology, imagining the world to be encircled by a great river. Okeanos in Greek, reflects the ancient Greek observation that a strong current flowed off Gibraltar and their subsequent assumption that it was a great river. (Compare also Samudra from Hindu mythology and Jörmungandr from Norse mythology.) The world was imagined to be enclosed by a celestial ocean above the heavens, and an ocean of the underworld below.
Artworks which depict maritime themes are known as marine art, a term which particularly applies to common styles of European painting of the 17th to 19th centuries.

See also

References

  1. ^ Drogin, Bob (October 24, 2003). "Census of Marine Life maps an ocean of species". http://www.latimes.com/new/la-na-fish2-2009aug02,0,5785256.story?page=1&track=ntothtml. Retrieved August 18, 2009. 
  2. ^ "Ocean". The Columbia Encyclopedia. 2002. New York: Columbia University Press
  3. ^ a b "Distribution of land and water on the planet". UN Atlas of the Oceans
  4. ^ Spilhaus first=Athelstan F. (July 1942). Maps of the whole world ocean. 32 (3). American Geographical Society).. pp. 431–5. 
  5. ^ Biology: Concepts & Connections. Chapter 34: The Biosphere: An Introduction to Earth's Diverse Environment. (sec 34.7)
  6. ^ a b ,"The World's Oceans and Seas". Encarta. http://encarta.msn.com/media_461547746/The_World's_Oceans_and_Seas.html. 
  7. ^ Qadri, Syed (2003). "Volume of Earth's Oceans". The Physics Factbook. http://hypertextbook.com/facts/2001/SyedQadri.shtml. Retrieved 2007-06-07. 
  8. ^ Drazen, Jeffrey C.. "Deep-Sea Fishes". School of Ocean Earth Science and Technology, University of University of Hawaiʻi at M?noa. http://www.soest.hawaii.edu/oceanography/faculty/drazen/fishes.htm. Retrieved 2007-06-07. 
  9. ^ BAD PHYSICS: Misconceptions spread by K-6 Grade School Textbooks
  10. ^ "Why is water blue?". Journal Chemical Education. 1994. p. 612. http://www.dartmouth.edu/~etrnsfer/water.htm. 
  11. ^ "Mystery Ocean Glow Confirmed in Satellite Photos". October 4, 2005. http://www.livescience.com/strangenews/051004_sea_glow.html. 
  12. ^ 11/21/2005, Usa today: A glowing sea, courtesy of algae Quote: "...The water glowed green in the direction of the movement...A: Little microscopic creatures (called Lingulodinium polyedrum) that glow in the dark caused the alluring strange display that night..."
  13. ^ 05 October 2005, New Scientist: Sea's eerie glow seen from space Quote: "...The ancient mariners were right. Tales of "milky seas" that glow bluish-white at night and extend as far as the horizon have been spun by sailors for centuries. Now this eerie glow has been spotted from space....The glowing area spanned 15,400 square kilometres (5,900 sq mi), an area the size of Connecticut (Image: Steven D Miller, US Naval Research Laboratory)..."
  14. ^ NASA, DAAC Study: The Incredible Glowing Algae Quote: "...Each year, the North Atlantic Ocean announces springtime by producing “blooms” large enough to be seen from space. These explosive increases in microscopic marine algae, called phytoplankton, appear as sudden bright blossoms in satellite imagery..."
  15. ^ Seager first=R. (2006). "The Source of Europe's Mild Climate"]. American Scientist. http://www.americanscientist.org/issues/feature/2006/4/the-source-of-europes-mild-climate. 
  16. ^ Rhines and Hakkinen (2003). "Is the Oceanic Heat Transport in the North Atlantic Irrelevant to the Climate in Europe?". ASOF Newsletter. http://www.realclimate.org/Rhines_hakkinen_2003.pdf. 
  17. ^ Hot "ice" may cover recently discovered planet
  18. ^ David A. Aguilar (2009-12-16). "Astronomers Find Super-Earth Using Amateur, Off-the-Shelf Technology". Harvard-Smithsonian Center for Astrophysics. http://www.cfa.harvard.edu/news/2009/pr200924.html. Retrieved January 23, 2010. 

Further reading

Pope, F. 2009. From eternal darkness springs cast of angels and jellied jewels. in The Times. November 23. 2009 p. 16 - 17.

External links


Source material

Up to date as of January 22, 2010
(Redirected to The Ocean article)

From Wikisource

The Ocean
by Nathaniel Hawthorne

The Ocean

.The Ocean has its silent caves,
Deep, quiet and alone;
Though there be fury on the waves,
Beneath them there is none.
^ If you cut Mount Everest off at sea level and put it on the ocean bottom in the Challenger Deep, there would still be over a mile of water over the top of it!
  • Deepest place in the ocean | Challenger Deep | Marianas Trench 21 January 2010 1:44 UTC www.extremescience.com [Source type: FILTERED WITH BAYES]
  • Ocean Studies - RAIN - 21 January 2010 1:44 UTC www.rain.org [Source type: General]

^ The swell of the ocean or other body of water in a high wind; motion of the water's surface; also, a single wave; a billow; as, there was a high sea after the storm; the vessel shipped a sea .
  • sea@Everything2.com 2 February 2010 17:017 UTC everything2.com [Source type: FILTERED WITH BAYES]

^ He has made fundamental, and pioneering contributions to our knowledge of ocean surface currents, deep circulation of the ocean, internal waves, surface waves, variations in Earth's rotation, ocean drilling, and tides.
  • Ocean Motion and Surface Currents 18 January 2010 11:37 UTC oceanmotion.org [Source type: Academic]


.The awful spirits of the deep
Hold their communion there;
And there are those for whom we weep,
The young, the bright, the fair.
^ It was such an honor to be shot by Jonathan Becker for this month's Bright Young Things feature in Vanity Fair.

^ The bottom line is, as creepy and foreign as those bizarre deep creatures are to us, there are more of them living on this planet than us!
  • Ocean zones | oceanography 18 January 2010 11:37 UTC www.extremescience.com [Source type: FILTERED WITH BAYES]

^ Bright Young Things in Vanity Fair .

Calmly the wearied seamen rest
Beneath their own blue sea.
The ocean solitudes are blest,
For there is purity.
.The earth has guilt, the earth has care,
Unquiet are its graves;
But peaceful sleep is ever there,
Beneath the dark blue waves.
^ Amelia Earhart we still search for you Out there in the ocean blue Your resting place is still unknown Did a watery grave become your home?
  • Oceania - Amelia Earhart - Last Flight 17 January 2010 2:10 UTC www.janesoceania.com [Source type: Original source]


Wiktionary

Up to date as of January 15, 2010

Definition from Wiktionary, a free dictionary

See also ocean, océan, oceán, óceán, oċean, and Océan

Contents

English

Etymology

From the vocabulary word ocean, inspired by the fashionable French female name Océane.

Proper noun

Singular
Ocean
Plural
-
Ocean
  1. A female given name of modern usage.

Anagrams

  • Anagrams of aceno
  • canoe

Strategy wiki

Up to date as of January 23, 2010
(Redirected to Category:Ocean Software article)

From StrategyWiki, the free strategy guide and walkthrough wiki

stub
This company category is a stub. Help us expand it with details as well as a {{company}} infobox. Reliable information can be researched on wikipedia or you can just search for "Ocean Software" on Google. Do this and you get a cookie.
Ocean Software
Founded ~1982
Located Manchester, UK
Website N/A

Subcategories

This category has only the following subcategory.

O

Pages in category "Ocean Software"

The following 13 pages are in this category, out of 13 total.

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  • Jurassic Park Part 2: The Chaos Continues

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Simple English

Earth's oceans
(World Ocean)

An ocean is a large area of salt water between continents. Oceans are very big and they join smaller seas together. Together, the oceans are like one "ocean", because all the "oceans" are joined. Oceans (or marine biomes) cover 70% of our planet.[1] The largest ocean is the Pacific Ocean. It covers 1/3 (one third) of the Earth's surface. The smallest ocean is the Arctic Ocean. Different water movements separate the Southern Ocean from the Atlantic, Pacific and Indian oceans. It is also known as the Antarctic Ocean, because it covers the area around Antarctica. Older maps may not use the names Arctic Ocean and Southern Ocean. The deepest ocean is the Pacific ocean. The deepest point is the Mariana Trench, being about 11,000 metres (36,200 feet) deep. The deep ocean is characterized by cold temperatures, high pressure, and complete darkness. Some very unusual organisms live in this part of the ocean. They do not require energy from the sun to survive, because they use chemicals from deep inside the earth.

Contents

Color

It is wrong to say that the oceans are blue because the water reflects the blue sky. Water has a very slight blue color that can only be seen in a very large amount of water. However, the main cause of the blue or blue/green color is that water absorbs the red part of the incoming light, and reflects the green and blue part of the light. [[File:|thumb|right]]

Plants and Animals

Organisms that live in oceans can live in salt water. They are affected by sunlight, temperature, water pressure, and water movement. Different ocean organisms live near the surface, in shallow waters, and in deep waters. Small plant organisms that live near the surface and use sunlight to produce food are called phytoplankton. Almost all animals in the ocean depend directly or indirectly on these plants. In shallow water, you may find lobsters and crabs. In deeper water, marine animals of many different shapes and sizes swim through the ocean. These include many types of fish, such as tuna, swordfish and marine mammals like dolphins and whales. The skies above the open ocean are home to large sea birds, such as the albatross.[1]

Harvesting the ocean

Nations like Russia and Japan have lots of huge ships that go to some of the world's best fishing areas for many months. These large ships have libraries, hospitals, schools, repair (fixing) shops and other things that are needed for fishermen and their families.

Many people look at the sea as a source of food, minerals and energy.

Fishing

Oceanographers estimate (guess) that over 15,300 types of fish live in the oceans, some of which are used for food.[2] Fish are a fine source of protein, so many people eat them. Fishing industries are very important because they let people have jobs and give food to millions of people. Today, usually through ocean fishing, the ocean supplies about 2% of the calories needed by the people living on Earth.[2] Tuna, anchovies, and herring are harvested close to the surface of the ocean.[2] Pollock, flounder and cod are caught near the ocean floor.[2] More than a million tons of herring are caught every year in the North Pacific and North Atlantic, and almost eight fish out of ten fish are eaten as food for humans. The other fish are used as fertilizer, glue, and pet and other animal food.[2]

Ocean temperatures

There are many different ocean temperatures in the open ocean, both vertically (from top to bottom) and horizontally. Icebergs are made over very cold waters at either pole, while waters at the equator are pretty warm.[2] Water cools and warms more slowly than land does, so land influenced by the ocean has later and milder seasons than land that is farther away from the ocean.

The surface part of the ocean, also called the mixed layer, is not much colder even when we go deeper down.[2] Below this surface zone is a layer of sudden temperature difference, called a thermocline. This is a middle layer hat is from the surface zone down to about 2,600 feet (800 m). Thermoclines may happen only at seasons or permanently, and may change depending on where and how deep it is. As evaporation happens, it begins cooling, and if the water evaporates very quickly, the water becomes saltier. The salty, cold water is denser, so it sinks. This is why warm and cold waters do not easily mix. Most animals and plants live in the warm upper layer. Below the thermocline, temperature in the deep zone is so cold it is just above freezing - between 32 &ndash 37.4 F (0 &ndash 3 C).[2]

References

  1. 1.0 1.1 English through Science (2010). Blue Planet. North America: McGrawHill. pp. 117 to 118. 
  2. 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 Sherwin, Frank (2004). The Ocean Book. P.O. Box 726, Green Forest, AR 72638: Master Books. ISBN 0-89051-401-1. 
krc:Океан

Citable sentences

Up to date as of December 25, 2010

Here are sentences from other pages on Mariana Trench, which are similar to those in the above article.








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