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Ocean

Ocean

:For other uses see Ocean (disambiguation) Ocean (disambiguation)] Ocean (from Okeanos, Greek for river, the ancient Greeks noticed that a strong current flowed off Gibraltar, and assumed it was a great river); covers almost three quarters (71%) of the surface of the Earth, and nearly half of the world's marine waters are over 3000 m deep. This global, interconnected body of salt water, called the World Ocean, is divided by the continents and archipelagos into the following four bodies, from the largest to the smallest: the Pacific Ocean, the Atlantic Ocean, the Indian Ocean, and the Arctic Ocean, and, according to some authorities such as International Hydrographic Organization(IHO), a fifth ocean, the Southern Ocean. Some geographers and some governments but not the US, recognize the IHO as defining official water body names and boundaries. (The US authority is the United States Board on Geographic Names.) The IHO officially sanctioned the Southern Ocean name only in 2000, but its definition by a line of latitude (with IHO members widely disputing which line of latitude) has left its acceptance as a fifth ocean open to question. The National Geographic Society and some other leading geographers and cartographers continue to use "South Pacific", "South Atlantic", and "Indian" Ocean for the waters around Antarctica. A few Oceanographers recognize only four oceans also, treating the Arctic Ocean (or the Arctic Sea) as a part of the Atlantic Ocean. Smaller regions of the oceans are called seas, gulfs, 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 where there are no continents. From this point of view, there are three "oceans" today: the World Ocean, and the Black and Caspian Seas that were formed by the collision of Cimmeria with Laurasia. The Mediterranean Sea is very nearly its own "ocean", being connected to the World Ocean through the Strait of Gibraltar, and indeed several times over the last few million years movement of the African Continent has closed the strait off entirely, making the Mediterranean a fourth "ocean". (The Black Sea is connected to the Mediterranean through the Bosporus, but this is in effect a natural canal, cut through continental rock some 7000 years ago, rather than a piece of oceanic sea floor like the Strait of Gibraltar.) The area of the World Ocean is 361 million km², its volume is 1370 million km³, and its average depth is 3790 m. Nearly half of the world's marine waters are over 3000 m deep. This does not include seas not connected to the World Ocean, such as the Caspian Sea. The total mass of the hydrosphere is about 1.4 × 10²¹ kg, ca. 0.023 % of the Earth's total mass. See sea water for a detailed discussion of ocean water composition, most notably its salinity.

Origins

The Oceans of the world most likely originated by comets striking the Earth.

Exploration

salinity Travel on the surface of the ocean through the use of boats 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. It has a maximum depth of 10,923 m (35,838 ft) [http://www.rain.org/ocean/ocean-studies-challenger-deep-mariana-trench.html]. It was fully surveyed in 1951 by the British naval vessel, "Challenger II" which gave its name to the deepest part of the trench, the "Challenger Deep". Much of the bottom of the world's oceans is unexplored and unmapped. A global image of many underwater features larger than 10 km was created in 1995 based on gravitational distortions of the nearby sea surface.

Climate

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). Ocean currents greatly affect Earth's climate by transferring warm or cold air and precipitation to coastal regions, where they may be carried inland by winds. The Antarctic Circumpolar Current encircles that continent, influencing the area's climate and connecting currents in several oceans.

Ecology

The oceans are home to the majority of plant and animal life on Earth. These lifeforms include:
- fish
- cetacea such as whales, dolphins and porpoises,
- cephalopods such as the octopus
- crustaceans such as lobsters and shrimp
- marine worms
- plankton
- krill

Economy

The oceans are essential to transportation: a huge portion of the world's goods are moved by ship between the world's seaports. Important ship canals include the Saint Lawrence Seaway, Panama Canal, and Suez Canal.

Ancient oceans

Continental drift has reconfigured the Earth's oceans, joining and splitting ancient oceans to form the current oceans. Ancient oceans include:
- Panthalassa, the vast world ocean that surrounded the Pangaea supercontinent.
- Tethys Ocean, the ocean between the ancient continents of Gondwana and Laurasia.
- Iapetus Ocean, the southern hemisphere ocean between Baltica and Avalonia.

Ocean rowing

Extraterrestrial oceans

Earth is the only known planet with liquid water on its surface, and is certainly the only such in our own solar system. However, liquid water is thought to be present under the surface of several natural satellites, particularly the Galilean moons of Europa, and, with less certainty, its fellows Callisto and Ganymede. 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 at this time. There is currently much debate over whether Mars once had an ocean of water in its northern hemisphere, and over what happened to it if it did; recent findings by the Mars Exploration Rover mission indicate it had some long-term standing water in at least one location, but its extent is not known. Liquid hydrocarbons are thought to be present on the surface of Titan, though it may be more accurate to describe them as "lakes" rather than an "ocean". The distribution of these liquid regions will hopefully be better known after the full analysis of data from the Huygens probe of the Cassini-Huygens space mission, which dropped onto Titan's surface in January 2005. Titan is also thought likely to have a subterranean water ocean under the mix of ice and hydrocarbons that forms its outer crust.

Oceans in film

- In the movie Muppet Treasure Island, a non-specific ocean is featured, and referred to as the "Big Blue Wet Thing". Oceans have also been featured in many other movies such as Free Willy. To list more, click edit beside "Oceans on Film"

External links

- [http://www.oceanexplorer.noaa.gov/ Ocean Explorer] - An educational and reference resource from NOAA
- [http://news.bbc.co.uk/2/hi/science/nature/4033555.stm Science taps into ocean secrets]
- [http://www.palomar.edu/oceanography/salty_ocean.htm Why is the ocean salty?]
- [http://ioc.unesco.org/oceanteacher/resourcekit/M3/Formats/Geography/OceansSeas.htm Official IHO boundaries of Oceans and Seas]
- [http://www.thehydrogenexpedition.com The Hydrogen Expedition] The first circumnavigation of the globe in a hydrogen fuel cell powered boat
- [http://www.coreocean.org Coreocean]
- [http://www.nopp.org/ NOPP - The National Oceanographic Partnership Program] Category:Bodies of water Category:Oceanography zh-min-nan:Hái-iûⁿ ko:대양 ms:Lautan ja:大洋 simple:Ocean th:มหาสมุทร

Ocean (disambiguation)

- For the bodies of water see Ocean.
- Ocean was a gospel rock band from the 1970s.
- Ocean is a place in the State of New Jersey.
- There are also places named Ocean City including one in New Jersey different from the above.
- Ocean Software is a software company, now owned by Infogrames.
- "Ocean" is a song by Lou Reed which appears on his eponymous album, and was also earlier recorded with the Velvet Underground.
- The Ocean is a Canadian passenger train operated by VIA Rail in Eastern Canada.
- "The Ocean" is a song by Led Zeppelin which was released on their album Houses of the Holy.

Continents

shows land mass with minimal distortion as only one continuous continent]] A continent (Latin continere, "to hold together") is a large continuous land mass. There are several conceptions of what a continent is, geographic, geologic, and tectonic.

Geographic continents

Because geography is defined by local convention, there are several conceptions as to which landmasses qualify as continents. There are names for six, but America is often divided, and Europe is often united with Asia. Ignoring cases where Antarctica is omitted, there are half a dozen lists. tectonic The 7-continent model is usually taught in Western Europe, the United States, Australia, and much of Asia. In Canada, the government-approved [http://atlas.gc.ca/site/english/maps/reference/international/world/referencemap_image_view Atlas of Canada] names 7 continents and teaches Oceania instead of Australia. The 6-continent combined-America model is taught in Iran, and Latin America. The 6-continent Eurasia model is preferred by the scientific community, and as such is commonly found in all parts of the world, but is especially used in Russia and other countries of Eastern Europe, and in Japan. Historians may use the 5-continent model in which North Africa is separated from Sub-Saharan Africa and attached to Eurasia (Jared Diamond) or the 4-continent Afro-Eurasian model (Andre Gunder Frank). In its original sense, "continent" meant (and still means) mainland. In the Greco-Roman world, there was but one known, the Continent, which we today call the Old World. In the mid 1600s Peter Heylin wrote in his Cosmographie that "A Continent is a great quantity of Land, not separated by any Sea from the rest of the World, as the whole Continent of Europe, Asia, Africa." As late as 1727 Ephraim Chambers wrote in his Cyclopædia, "The world is ordinarily divided into two grand continents: the old and the new." However, since Classical times this Continent was divided into "peninsulas" which also came to be called continents, since they were great land masses themselves. Through the Middle Ages, there were three such continents in the Western conception: Europe, Africa, and Asia. The European discovery of America in 1492 made four; and Australia in 1606 would make five, though not right away: as late as 1813 geographers wrote of Australia as "New Holland, an immense Island, which some geographers dignify with the appellation of another continent". However, dividing America in two was commonplace by this time, and would also produce a fifth continent. The idea of the Five Continents is still strong in Europe and Asia, and is represented by the five rings on the Olympic flag. Antarctica was sighted in 1820, for the sixth and last continent to be given a separate name, though a great "antarctic" (antipodean) landmass had been anticipated for millennia. Dividing the Americas now made seven continents, nicely symmetrical with the magical number of the Seven Seas, Seven Heavens, and the seven heavenly bodies that gave their names to the seven days of the week. However, this division never appealed to Latin America, which saw itself spanning America as a single landmass, and there the conception of six continents remains, as it does in scattered other countries such as Japan. From a modern perspective, the continent with the least reason for separate recognition is Europe, and in scientific circles people generally prefer to subsume Europe and Asia into Eurasia. This appealed to Russia, which spans Eurasia, and in Russia and (at least formerly) in Eastern Europe, Eurasia is or was taught as being one of six continents. Geographers and historians often find it useful to define larger land masses connected by land bridges: # Africa-Eurasia (also called Eurafrasia): the combined land mass of Africa and Eurasia; # America (or the Americas): the combined land mass of North America and South America; # Laurasia: the combined land mass of Eurasia and North America, which were connected by Beringia during the Ice Age; # Sahul: the combined land mass of Australia, New Guinea, and Tasmania during the Ice Age. That is, during the last Ice Age, there were three large landmasses: Africa-Eurasia + America (which has no name), Sahul, and Antarctica. These larger land masses are usually considered supercontinents rather than continents, however. In the last century it has also become conventional to subdivide Eurasia into the regions of Europe, Asia, and the Middle East. America is often divided into the regions of North America, Central America, and South America. Continents are also sometimes subdivided into subcontinents that are isolated by geological features. The prototype of this is the Indian subcontinent. Islands are usually considered to belong geographically to the continent they are closest to. The Coral Sea and South Pacific islands may be associated with Australia/Australasia to form the "continent" of Oceania (though the Pacific islands without Australia are also called Oceania). The British Isles have always been considered part of Europe, and Greenland is considered part of North America. When the Continent is referred to without clarification by a speaker of British English, it is usually presumed to mean Continental Europe, that is Europe, explicitly excluding Great Britain and Ireland. The Continental United States excludes Hawaii. Contiguous or Co(n)terminous United States means the United States without Alaska or Hawaii (the "Lower 48"), but it is very common for people to say continental for contiguous. See also List of countries by continent, Satellite Images of Continents.

Geologic continents

Geologically, the surface of Earth consists of many tectonic plates, consisting of rigid lithospheric mantle and crust moving together over the much less viscous asthenosphere. Continental crust is primarily granitic in composition, overlain by sedimentary and metamorphic rocks. Much of the continental crust extends above sea level as dry land. Oceanic crust is basaltic in composition, and much thinner than continental crust, thus generally lying below sea level. Although from a human perspective shallow inland seas such as the Bering Sea appear to divide up land masses into continents, such ephemeral features do not define continents geologically. For instance, many times over the past few million years, the continents of Eurasia and America were connected by dry land. A geologic continent, therefore, is a continuous piece of continental crust, whether wet or dry at a particular time. As such, Laurasia and Africa-Arabia are one continent, which for the past three million years has also been linked to South America. This world-spanning land mass has no name except for the Classical meaning of "The Continent". The other large geologic continents are Sahul and Antarctica, but there are many so-called microcontinents as well: Madagascar, the Seychelles (the northern Mascarene Plateau), New Zealand, New Caledonia, etc., which are splinters of the ancient supercontinent of Gondwana. Note that volcanic Iceland is an exposed bit of oceanic crust at the mid-ocean ridge, and therefore not a microcontinent. Likewise, the British Isles, Sri Lanka, Borneo, and Newfoundland are integral parts of the Laurasian continent which happen to be separated by shallow (and temporary) inland seas flooding its margins.

Tectonic plates

During the 20th century, it became accepted by geologists that continents move location on the face of the planet over the geologic timescale, a process known as continental drift, explained by the theory of plate tectonics. It is the tectonic plates that have drifted, broken apart and joined together over time to give rise to the continents we now recognize. Consequently, in the geological past and prior to the present continents, other continents existed - see :Category:Historical continents. Occasionally there are calls for the continents to be defined by the tectonic plates that carry them. However, not only would this make Arabia on the Arabian plate and India on the Indian plate continents, but also Central America on the Caribbean plate and California on the Pacific plate, and this definition has never been widely accepted.

Pacific Ocean

:For other meanings of Pacific, see Pacific (disambiguation). The Pacific Ocean (from the Latin name Mare Pacificum, "peaceful sea", bestowed upon it by the Portuguese explorer Ferdinand Magellan) is the world's largest body of water. It encompasses a third of the Earth's surface, having an area of 179.7 million km² (69.4 million sq miles). Extending approximately 15,500 km (9,600 miles) from the Bering Sea in the Arctic to the icy margins of Antarctica's Ross Sea in the south (although the Antarctic regions of the Pacific are sometimes described as part of the circumpolar Southern Ocean)the Pacific reaches its greatest east-west width at about 5°N latitude, where it stretches approximately 19,800 km (12,300 miles) from Indonesia to the coast of Colombia. The western limit of the ocean is often placed at the Strait of Malacca. The lowest point on earth—the Mariana Trench—lies some 10,911 m (35,797 ft) below sea level. The Pacific contains about 25,000 islands (more than the total number in the rest of the world's oceans combined), the majority of which are found south of the equator. (See: Pacific Islands.) Along the Pacific Ocean's irregular western margins lie many seas, the largest of which are the Celebes Sea, Coral Sea, East China Sea, Sea of Japan, South China Sea, Sulu Sea, Tasman Sea, and Yellow Sea. The Straits of Malacca joins the Pacific and the Indian Oceans on the west, and the Straits of Magellan links the Pacific with the Atlantic Ocean on the east. As the Pacific straddles the ±180° longitude where East becomes West, the Asian side of the ocean (where latitudes are E) is correctly referred to as East Pacific and the opposite side (eastwards) where latitudes are W is the West Pacific. To retain the popular "left is western" and "right is eastern" means of reference, the Western Pacific is thus the East Pacific and the Eastern Pacific the West Pacific. The International Date Line follows the ±180° longitude to the greater part of its North-South demarcation but veers far eastwards around Kiribati (Caroline Island, which, not coincidentally, was renamed Millennium Island) and westwards round the Aleutian Islands as can be seen on the map at International Date Line. For most of Ferdinand Magellan's voyage from the Straits of Magellan to the Philippines, the Portuguese explorer indeed found the ocean peaceful. However, the Pacific is not always peaceful. Many typhoons and hurricanes batter the islands of the Pacific and the lands around the Pacific rim are full of volcanoes and often rocked by earthquakes. Tsunamis, caused by underwater earthquakes, have devastated many islands and wiped out whole towns. Tsunami

Ocean bottom

The ocean floor of the central Pacific basin is relatively uniform, an abyssal plain with a mean depth of about 4270 m (14,000 ft). The major irregularities in the basin are the extremely steep-sided, flat-topped submarine peaks known as seamounts. The western part of the floor consists of mountain arcs that rise above the sea as island groups, such as the Solomon Islands and New Zealand, and deep oceanic trenches, such as the Mariana Trench, the Philippine Trench, and the Tonga Trench. Most of the trenches lie adjacent to the outer margins of the wide western Pacific continental shelf. Along the eastern margin of the Pacific Basin is the East Pacific Rise, which is a part of the worldwide mid-oceanic ridge. About 3000 km (1800 miles) across, the rise stands about 3 km (2 miles) above the adjacent ocean floor. Because a relatively small land area drains into the Pacific, and because of the ocean's immense size, most sediments are authigenic or pelagic in origin. Authigenic sediments include montmorillonite and phillipsite. Pelagic sediments derived from seawater include pelagic red clays and the skeletal remains of sea life. Terrigenous sediments eroded from land masses are confined to narrow marginal bands close to land.

Elevation extremes

- lowest point: -10,924 m (-35,840 ft). at the bottom of the Mariana Trench
- highest point: 0 m (0 ft), sea level.

Water characteristics

Water temperatures in the Pacific vary from freezing in the poleward areas to about 29°C (84°F) near the equator. Salinity also varies latitudinally. Water near the equator is less salty than that found in the mid-latitudes because of abundant equatorial precipitation throughout the year. Poleward of the temperate latitudes salinity is also low, because little evaporation of seawater takes place in these frigid areas. The surface circulation of Pacific waters is generally clockwise in the Northern Hemisphere (the North Pacific Gyre) and anti-clockwise in the Southern Hemisphere. The North Equatorial Current, driven westward along latitude 15°N by the trade winds, turns north near the Philippines to become the warm Japan or Kuroshio Current. Turning eastward at about 45°N, the Kuroshio forks and some waters move northward as the Aleutian Current, while the rest turn southward to rejoin the North Equatorial Current. The Aleutian Current branches as it approaches North America and forms the base of an anti-clockwise circulation in the Bering Sea. Its southern arm becomes the chilled slow, south-flowing California Current. The South Equatorial Current, flowing west along the equator, swings southward east of New Guinea, turns east at about 50°S, and joins the main westerly circulation of the Southern Pacific, which includes the Earth-circling Antarctic Circumpolar Current. As it approaches the Chilean coast, the South Equatorial Current divides; one branch flows around Cape Horn and the other turns north to form the Peru or Humboldt Current.

Climate

Only the interiors of the large land masses of Australia, New Guinea, and New Zealand escape the pervasive climatic influence of the Pacific. Within the area of the Pacific, five distinctively different climatic regions exist: the mid-latitude westerlies, the trades, the monsoon region, the typhoon region, and the doldrums. Mid-latitude westerly air streams occur in both northerly and southerly latitudes, bringing marked seasonal differences in temperature. Closer to the equator, where most of the islands lie, steadily blowing trade winds allow for relatively constant temperatures throughout the year of 21-27°C (70-81°F). The monsoon region lies in the far western Pacific between Japan and Australia. Characteristic of this climatic region are winds that blow from the continental interior to the ocean in winter and in the opposite direction in summer. Consequently, a marked seasonality of cloudiness and rainfall occurs. Typhoons often cause extensive damage in the west and southwest Pacific. The greatest typhoon frequency exists within the triangle from southern Japan to the central Philippines to eastern Micronesia. Although more poorly defined than the other climatic regions, two major doldrum areas lie within the ocean, one located off the western shores of Central America and the other within the equatorial waters of the western Pacific. Both areas are noted for their high humidity, considerable cloudiness, light fluctuating winds, and frequent calms.

Geology

The Andesite Line is the most significant regional distinction in the Pacific. It separates the deeper, basic igneous rock of the Central Pacific Basin from the partially submerged continental areas of acidic igneous rock on its margins. The Andesite Line follows the western edge of the islands off California and passes south of the Aleutian arc, along the eastern edge of the Kamchatka Peninsula, the Kuril Islands, Japan, the Mariana Islands, the Solomon Islands, and New Zealand. The dissimilarity continues northeastward along the western edge of the Albatross Cordillera along South America to Mexico, returning then to the islands off California. Indonesia, the Philippines, Japan, New Guinea, and New Zealand—all eastward extensions of the continental blocks of Australia and Asia—lie outside the Andesite Line. Within the closed loop of the Andesite Line are most of the deep troughs, submerged volcanic mountains, and oceanic volcanic islands that characterize the Central Pacific Basin. It is here that basaltic lavas gently flow out of rifts to build huge dome-shaped volcanic mountains whose eroded summits form island arcs, chains, and clusters. Outside the Andesite Line, volcanism is of the explosive type, and the Pacific Ring of Fire is the world's foremost belt of explosive volcanism.

Landmasses

The largest landmass entirely within the Pacific Ocean is the island of New Guinea— the second largest in the world. Almost all of the smaller islands of the Pacific lie between 30°N and 30°S, extending from South-east Asia to Easter Island; the rest of the Pacific Basin is almost entirely submerged. The great triangle of Polynesia, connecting Hawaii, Easter Island, and New Zealand, encompasses the island arcs and clusters of the Cook, Marquesas, Samoa, Society, Tokelau, Tonga, and Tuamotu islands. North of the equator and west of the international date line are the numerous small islands of Micronesia, including the Caroline Islands, the Marshall Islands, and the Mariana Islands. In the southwestern corner of the Pacific lie the islands of Melanesia, dominated by New Guinea. Other important island groups of Melanesia include the Bismarck Archipelago, Fiji, New Caledonia, the Solomon Islands, and Vanuatu. Islands in the Pacific Ocean are of four basic types: continental islands, high islands, coral reefs, and uplifted coral platforms. Continental islands lie outside the Andesite Line and include New Guinea, the islands of New Zealand, and the Philippines. These islands are structurally associated with the nearby continents. High islands are of volcanic origin, and many contain active volcanoes. Among these are Bougainville, Hawaii, and the Solomon Islands. The third and fourth types of islands are both the result of coralline island building. Coral reefs are low-lying structures that have built up on basaltic lava flows under the ocean's surface. One of the most dramatic is the Great Barrier Reef off northeastern Australia. A second island type formed of coral is the uplifted coral platform, which is usually slightly larger than the low coral islands. Examples include Banaba (formerly Ocean Island) and Makatea in the Tuamotu group of French Polynesia.

History and economy

See the Oceania article for information on one set of the Pacific Island states listed below here. Important human migrations occurred in the Pacific in prehistoric times, most notably those of Polynesians from Tahiti to Hawaii and New Zealand. The ocean was sighted by Europeans early in the 16th century, first by Vasco Núñez de Balboa (1513) and then by Ferdinand Magellan, who crossed the Pacific during his circumnavigation (1519-1522). In 1564 conquistadors crossed the ocean from Mexico led by Miguel López de Legazpi who sailed to the Philippines and Mariana Islands. For the remainder of the 16th century Spanish influence was paramount, with ships sailing from Spain to the Philippines, New Guinea, and the Solomons. The Manila Galleons linked Manila and Acapulco. During the 17th century the Dutch, sailing around southern Africa, dominated discovery and trade; Abel Janszoon Tasman discovered (1642) Tasmania and New Zealand. The 18th century marked a burst of exploration by the Russians in Alaska and the Aleutian Islands, the French in Polynesia, and the British in the three voyages of James Cook (to the South Pacific and Australia, Hawaii, and the North American Pacific Northwest). Growing imperialism during the 19th century resulted in the occupation of much of Oceania by Great Britain and France, followed by the United States. Significant contributions to oceanographic knowledge were made by the voyages of the HMS Beagle in the 1830s, with Charles Darwin aboard; the HMS Challenger during the 1870s; the U.S.S. Tuscarora (1873-76); and the German Gazelle (1874-1876). Although the United States took the Philippines in 1898, Japan controlled the western Pacific by 1914, and occupied many other islands during World War II. By the end of that war the U.S. Pacific Fleet was the virtual master of the ocean. Seventeen independent states are located in the Pacific: Australia, Fiji, Japan, Kiribati, Marshall Islands, Micronesia, Nauru, New Zealand, Palau, Papua New Guinea, the Philippines, Samoa, Solomon Islands, Republic of China (Taiwan), Tonga, Tuvalu, and Vanuatu. Eleven of these nations have achieved full independence since 1960. The Northern Mariana Islands are self-governing with external affairs handled by the United States, and Cook Islands and Niue are in similar relationships with New Zealand. Also within the Pacific are the U.S. state of Hawaii and several island territories and possessions of Australia, Chile, Ecuador, France, Japan, New Zealand, the United Kingdom, and the United States. The exploitation of the Pacific's mineral wealth is hampered by the ocean's great depths. In shallow waters of the continental shelves off the coasts of Australia and New Zealand, petroleum and natural gas are extracted, and pearls are harvested along the coasts of Australia, Japan, Papua New Guinea, Nicaragua, Panama, and the Philippines, although in sharply declining volume. The Pacific's greatest asset is its fish. The shoreline waters of the continents and the more temperate islands yield herring, salmon, sardines, snapper, swordfish, and tuna, as well as shellfish. In 1986, the member nations of the South Pacific Forum declared the area a nuclear-free zone in an effort to halt nuclear testing and prevent the dumping of nuclear waste there.

Ports and harbours

- Acapulco (Mexico)
- Anchorage (United States)
- Auckland (New Zealand)
- Brisbane (Australia)
- Callao (Peru)
- Hong Kong (Hong Kong (China (PRC)))
- Honolulu (United States)
- Kobe (Japan)
- Long Beach (United States)
- Los Angeles (United States)
- Panama City (Panama)
- Portland (Oregon) (United States)
- Prince Rupert (Canada)
- San Diego (United States)
- San Francisco (United States)
- Sapporo (Japan)
- Seattle (United States)
- Shanghai (China (PRC))
- Sydney (Australia)
- Taipei (China (ROC))
- Vancouver (Canada)
- Victoria (Canada)
- Vladivostok (Russia)
- Yokohama (Japan)

Bibliography

- Barkley, R.A., Oceanographic Atlas of the Pacific Ocean (1969)
- Cameron, I., Lost Paradise (1987)
- Couper, A., Development in the Pacific Islands (1988)
- Crump, D.J., ed., Blue Horizons (1980)
- Gilbert, John, Charting the Vast Pacific (1971)
- Lower, J. Arthur, Ocean of Destiny: A Concise History of the North Pacific, 1500-1978 (1978)
- Oliver, D.L., The Pacific Islands, 3nd ed. (1989)
- Ridgell, R., Pacific Nations and Territories, 2nd ed. (1988)
- Soule, Gardner, The Greatest Depths (1970)
- Spate, O.H., Paradise Found and Lost (1988)
- Terrell, J.E., Prehistory in the Pacific Islands (1986). :Based on public domain text from US Naval Oceanographer

External links

- [http://www.epic.noaa.gov/epic/ewb/ EPIC Pacific Ocean Data Collection] Viewable on-line collection of observational data
- [http://dapper.pmel.noaa.gov/dchart/ NOAA In-situ Ocean Data Viewer] Plot and download ocean observations
- [http://www.mapsouthpacific.com/ Map South Pacific]
- [http://www.oscar.noaa.gov/datadisplay/ NOAA Ocean Surface Current Analyses - Realtime (OSCAR)] Near-realtime Pacific Ocean Surface Currents derived from satellite altimeter and scatterometer data
- [http://floats.pmel.noaa.gov/floats/ NOAA PMEL Argo profiling floats] Realtime Pacific Ocean data
- [http://www.pmel.noaa.gov/tao/jsdisplay/ NOAA TAO El Nino data] Realtime Pacific Ocean El NIno buoy data
- [http://www.southpacific.org/ South Pacific Organizer] Category:Oceans
- zh-min-nan:Thài-pêng-iûⁿ ko:태평양 ja:太平洋 simple:Pacific Ocean th:มหาสมุทรแปซิฟิก

Indian Ocean

:This article is about the water body. For the Indian fusion music band, see Indian Ocean (band). The Indian Ocean is the third-largest body of water in the world, covering about 20% of the Earth's water surface. It is bounded on the north by southern Asia (the Indian subcontinent); on the west by the Arabian Peninsula and Africa; on the east by the Malay Peninsula, the Sunda Islands, and Australia; and on the south by the Southern Ocean. It is separated from the Atlantic Ocean by the 20°east meridian south of Africa, and from the Pacific by the 147°east meridian. The northernmost extent of the Indian Ocean is approximately 30°north latitude in the Persian Gulf. This ocean is nearly 10,000 km (6,200 mi) wide at the southern tips of Africa and Australia; its area is 73,556,000 km² (28,400,000 mi²), including the Red Sea and the Persian Gulf. The ocean's volume is estimated to be 292,131,000 km³ (70,086,000 mi³). Small islands dot the continental rims. Island nations within the ocean are Madagascar (formerly Malagasy Republic), the world's fourth largest island; Comoros; Seychelles; Maldives; Mauritius; and Sri Lanka. Indonesia borders it. The ocean's importance as a transit route between Asia and Africa has made it a scene of conflict. Because of its size, however, no one nation had successfully dominated until the early 1800s when Britain controlled much of the surrounding land. right

Environment

The African, Indian, and Antarctic crustal plates converge in the Indian Ocean. Their junctures are marked by branches of the Mid-Oceanic Ridge forming an inverted Y, with the stem running south from the edge of the continental shelf near Mumbai, India. The eastern, western, and southern basins thus formed are subdivided into smaller basins by ridges. The ocean's continental shelves are narrow, averaging 200 km (125 mi) in width. An exception is found off Australia's western coast, where the shelf width exceeds 1,000 km (600 mi). The average depth of the ocean is 3,890 m (12,760 ft). Its deepest point, in the Java Trench, is estimated to be 7,450 m (24,442 ft). North of 50° south latitude, 86% of the main basin is covered by pelagic sediments, of which more than one-half is globigerina ooze. The remaining 14% is layered with terrigenous sediments. Glacial outwash dominates the extreme southern latitudes.

Climate

The climate north of the equator is affected by a Monsoon wind system. Strong northeast winds blow from October until April; from May until October south and west winds prevail. In the Arabian Sea the violent monsoon brings rain to the Indian subcontinent. In the southern hemisphere the winds generally are milder, but summer storms near Mauritius can be severe. When the monsoon winds change, cyclones sometimes strike the shores of the Arabian Sea and the Bay of Bengal.

Hydrology

Bay of Bengal Among the few large rivers flowing into the Indian Ocean are the Zambezi, Arvandrud/Shatt-al-Arab, Indus, Ganges, Brahmaputra, and Irrawaddy. Currents are largely controlled by the monsoon. Two large circular currents, one in the northern hemisphere flowing clockwise and one south of the equator moving counterclockwise, constitute the dominant flow pattern. During the winter monsoon, however, currents in the north are reversed. Deepwater circulation is controlled primarily by inflows from the Atlantic Ocean, the Red Sea, and Antarctic currents. North of 20°south latitude the minimum surface temperature is 22°C (72°F), exceeding 28°C (82°F) to the east. Southward of 40°south latitude, temperatures drop quickly. Surface water salinity ranges from 32 to 37 parts per 1,000, the highest occurring in the Arabian Sea and in a belt between southern Africa and southwestern Australia. Pack ice and icebergs are found throughout the year south of about 65°south latitude. The average northern limit of icebergs is 45°south latitude.

Economy

The Indian Ocean provides major sea routes connecting the Middle East, Africa, and East Asia with Europe and the Americas. It carries a particularly heavy traffic of petroleum and petroleum products from the oilfields of the Persian Gulf and Indonesia. Large reserves of hydrocarbons are being tapped in the offshore areas of Saudi Arabia, Iran, India, and western Australia. An estimated 40% of the world's offshore oil production comes from the Indian Ocean. Beach sands rich in heavy minerals and offshore placer deposits are actively exploited by bordering countries, particularly India, South Africa, Indonesia, Sri Lanka, and Thailand. The warmth of the Indian Ocean keeps phytoplankton production low, except along the northern fringes and in a few scattered spots elsewhere; life in the ocean is thus limited. Fishing is confined to subsistence levels. Its fish are of great and growing importance to the bordering countries for domestic consumption and export. Fishing fleets from Russia, Japan, South Korea, and Taiwan also exploit the Indian Ocean, mainly for shrimp and tuna.

History

The earliest known civilizations, in the valleys of the Nile, Euphrates, Tigris, and Indus rivers and in Southeast Asia, have developed near the Indian Ocean. During Egypt's 1st dynasty (c. 3000 BCE), sailors were sent out onto its waters, journeying to Punt, thought to be part of present-day Somalia. Returning ships brought gold and Myrrh. Phoenicians of the 3rd millennium BCE may have entered the area, but no settlements resulted. The Indian Ocean is far calmer and thus open to trade earlier than the Atlantic or Pacific. The powerful monsoons also meant ships could easily sail them west early in the season, then wait a few months and return eastwards. This allowed Indonesian peoples to cross the Indian Ocean to settle in Madagascar. In the second or first century BCE Eudoxus of Cyzicus was the first Greek to cross the Indian Ocean. Hippalus is said to have discovered the direct route from Arabia to India around this time. During the first and second century CE intensive trade relations developed between Roman Egypt and the Tamil kingdoms of the Cheras, Cholas and Pandyas in Southern India. Like the Indonesian people above, the western sailors used the monsoon to cross the Ocean. The unknown author of the Periplus of the Erythraean Sea describes this route and the ports and trade goods along the coasts of Africa and India around 70 CE. In 1497 Vasco da Gama rounded the Cape of Good Hope and sailed to India, the first European to do so. The European ships, armed with heavy cannon, quickly came to dominate the trade. Portugal at first attempted to achieve pre-eminence setting up forts an the important straits and ports. But the small nation was unable to support such a vast project and they were replaced in the mid-1600s by other European powers. The Dutch East India Company (1602-1798) sought control of trade with the East across the Indian Ocean. France and Britain established trade companies for the area. Eventually Britain became the principal power and by 1815 dominated the area. The opening of the Suez Canal in 1869 revived European interest in the East, but no nation was successful in establishing trade dominance. Since World War II the United Kingdom has withdrawn from the area, to be only partially replaced by India, the USSR, and the United States. The last two have tried to establish hegemony by negotiating for naval base sites. Developing countries bordering the ocean, however, seek to have it made a "zone of peace" so that they may use its shipping lanes freely. Though the United States did manage to salvage a naval base for itself at Deigo Garcia in the middle of the Indian Ocean. On December 26 2004 the countries surrounding the Indian Ocean were hit by tsunamis caused by the 2004 Indian Ocean earthquake. The waves resulted in more than 226,000 deaths and over 1 million homeless.

Data

Southern Ocean: A spring 2000 decision by the International Hydrographic Organization delimited a fifth world ocean, stripping the southern portions of the Indian Ocean. The new ocean extends from the coast of Antarctica north to 60°south latitude which coincides with the Antarctic Treaty Limit. The Indian Ocean remains the third-largest of the world's five oceans. Area:
- total: 68.556 million km²
- seas: includes Andaman Sea, Arabian Sea, Bay of Bengal, Great Australian Bight, Gulf of Aden, Gulf of Oman, Laccadive Sea, Mozambique Channel, Persian Gulf, Red Sea, Strait of Malacca, and other tributary water bodies Coastline: 66,526 km Climate: northeast monsoon (December to April), southwest monsoon (June to October); tropical cyclones occur during May/June and October/November in the northern Indian Ocean and January/February in the southern Indian Ocean Terrain: surface dominated by counterclockwise gyre (broad, circular system of currents) in the southern Indian Ocean; unique reversal of surface currents in the northern Indian Ocean; low atmospheric pressure over southwest Asia from hot, rising, summer air results in the southwest monsoon and southwest-to-northeast winds and currents, while high pressure over northern Asia from cold, falling, winter air results in the northeast monsoon and northeast-to-southwest winds and currents; ocean floor is dominated by the Mid-Indian Ocean Ridge and subdivided by the Southeast Indian Ocean Ridge, Southwest Indian Ocean Ridge, and Ninetyeast Ridge Graphics of the seabed terrain produced by the Royal Navy & British Geological Survey in 2005 can be found here. Elevation extremes:
- lowest point: Java Trench -7,258 m
- highest point: sea level 0 m Natural resources: oil and gas fields, fish, shrimp, sand and gravel aggregates, placer deposits, polymetallic nodules Environment - current issues: endangered marine species include the dugong, seals, turtles, and whales; oil pollution in the Arabian Sea, Persian Gulf, and Red Sea Geography - note: major chokepoints include Bab el Mandeb, Strait of Hormuz, Strait of Malacca, southern access to the Suez Canal, and the Lombok Strait Ports and harbors: Calcutta (India), Chennai (Madras; India), Colombo (Sri Lanka), Durban (South Africa), Jakarta (Indonesia), Karachi (Pakistan), Fremantle (Australia), Mumbai (Bombay; India), Richards Bay (South Africa), Visakhapatnam (India),Kochi(India)

References

- Braun, D., The Indian Ocean (1983)
- Chandra, S., ed., The Indian Ocean (1987);
- Chaudhuri, K. N., Trade and Civilization in the Indian Ocean (1985);
- Cousteau, Jacques-Yves, and Diole, Philippe, Life and Death in a Coral Sea (1971);
- Cubitt, Gerald, Islands of the Indian Ocean (1975);
- Das Gupta, A., and Pearson, M.N., India and the Indian Ocean (1987);
- Dowdy, W. L., and Trood, R., eds., The Indian Ocean (1985);
- Kerr, A., ed., Resources and Development in the Indian Ocean Region (1981);
- Nairn, A. E., and Stehli, F. G., eds., The Ocean Basins and Margins, Vol. 6: The Indian Ocean (1982);
- Ostheimer, John M., ed., The Politics of the Western Indian Ocean Islands (1975);
- Toussaint, Auguste, The History of the Indian Ocean, trans. by June Guicharnaud (1966). Much of this text is based on public domain text by US Naval Oceanographer at: http://oceanographer.navy.mil/indian.html

External links

- [http://dapper.pmel.noaa.gov/dchart/ NOAA In-situ Ocean Data Viewer] Plot and download ocean observations Category:Oceans Category:Indian Ocean zh-min-nan:Ìn-tō·-iûⁿ ko:인도양 ja:インド洋 simple:Indian Ocean th:มหาสมุทรอินเดีย

International Hydrographic Organization

ja:国際水路機関 The International Hydrographic Organization (IHO) is an intergovernmental international organization established in 1921. The IHO was the outgrowth of international conferences and congresses held as early as 1889. The IHO is composed of its member states (represented by their respective hydrographic offices) with administration through the International Hydrographic Bureau with headquarters in Monaco. Direction of the Bureau is through directors elected by member states. The organization's function is to coordinate Hydrography and hydrographic activities of the member states. The IHO does not itself control significant hydrographic assets. The organization's goals are stated as "support the safety in navigation and the protection of the marine environment" with support of coordinated and uniform hydrographic products and surveys and by improving techniques of member states for producing those products. The IHO publishes Limits of Oceans and Seas, which specifies the boundaries between the oceans. In 2000 they officially defined the boundaries of the Southern Ocean.

External links

- [http://www.iho.shom.fr/ International Hydrographic Organization] website
- [http://www.iho.shom.fr/links/listms.htm IHO Member States] Category:Hydrography

United States Board on Geographic Names

The United States Board on Geographic Names (BGN) is an American federal body whose purpose is to establish and maintain uniform usage of geographic names throughout the U.S. government. The Board was created in 1890; its present form derives from a law of 1947. The Board has developed principles, policies, and procedures governing the use of both domestic and foreign geographic names. It also deals with the names of geographical features underseas and in Antarctica. Although its official purpose is to resolve name problems and new name proposals for the federal government, the Board also plays a similar role for the general public. Any person or organization, public or private, may make inquiries or request the Board to render formal decisions on proposed new names, proposed name changes, or names that are in conflict.

External links

- [http://geonames.usgs.gov/bgn.html Board on Geographic Names] Board on Geographic Names Category:Place names

Latitude

Latitude, sometimes denoted by the Greek letter φ, gives the location of a place on Earth north or south of the Equator. Latitude is an angular measurement ranging from 0° at the Equator to 90° at the poles (90º N or 90º S). Co-latitude is the complement of latitude. complement showing lines of latitude, which appear straight and horizontal in this projection, but are actually circular with different radii.]]

Lines of latitude

All locations of a given latitude are collectively referred to as a line of latitude or parallel, because they are coplanar, and all such planes are parallel to the Equator. Lines of latitude other than the Equator are approximately small circles on the surface of the Earth; they are not geodesics since the shortest route between two points at the same latitude involves moving farther away from the equator. A specific latitude may then be combined with a specific longitude to give a precise position on the Earth's surface.

Subdivisions

Each degree of latitude is further sub-divided into 60 minutes (one arcminute of latitude is exactly one nautical mile or 1852 metres), each of which divides into 60 seconds. A latitude is thus specified as 13° 19′ 43" N. For high accuracy, the seconds are specified with a decimal fraction. An alternative representation uses degrees and minutes, where parts of a minute are expressed as a decimal fraction, thus: 13° 19.717′ N. Degrees expressed as a decimal number (Decimal Degree notation) is more often used: 13.32861° N. Sometimes, the North/South suffix is replaced by a negative sign for South (-90º for the south pole).

Important latitudes

Latitudes of particular importance are the Tropic of Cancer (latitude 23°27′ north), the Tropic of Capricorn (latitude 23°27′ south), the Arctic Circle (latitude 66°33′ north), and the Antarctic Circle (latitude 66°33′ south). Only at latitudes between the Tropics is it possible for the sun to be at the zenith. Only north of the Arctic Circle or south of the Antarctic Circle is the midnight sun possible.

Effect of latitude

A region's latitude has a great effect on its climate and weather. Latitude more loosely determines tendencies in climate, polar auroras, prevailing winds, and other physical characteristics of geographic locations.

Types of latitude

Because the Earth is slightly flattened by its rotation, cartographers refer to a variety of auxiliary latitudes to precisely adapt spherical projections according to their purpose.

Common "latitude"

- In common usage, "latitude" refers to geodetic or geographic latitude φ and is the angle between the equatorial plane and a line that is normal to the reference spheroid, which approximates the shape of the Earth to account for flattening of the poles and bulging of the equator. The expressions following assume elliptical polar sections with eccentricity e, and that all sections parallel to the equatorial plane are circular. Geographic latitude (with longitude) then provides a Gauss map.

Reduced latitude

- Reduced or parametric latitude β is the latitude of the same radius on the sphere with the same equator. ::

\beta=\arctan\!\left\\,\!

Authalic latitude

- Authalic latitude ξ gives an area-preserving transform to the sphere. :::

\xi=\arcsin\!\left\\,\!

\mbox Q\!\left\=\left|\frac-\frac\ln\!\left\\right|

Rectifying latitude

- Rectifying latitude μ is the surface distance from the equator, scaled so the pole is 90°. Unfortunately, it is an incomplete elliptic integral: ::

\mu=k\int_^\phi\fracdx\,\!

Conformal latitude

- Conformal latitude χ gives an angle-preserving (conformal) transform to the sphere. ::

\chi=2\arctan\!\left\-\frac\,\!

Geocentric latitude

- The geocentric latitude φ_g is the angle between the equatorial plane and a line from the center of the Earth. ::

\phi_g=\arctan\left\\,\!

For other planets such as Mars, geographic and geocentric latitude are called "planetographic" and "planetocentric" latitude, respectively. Most maps of Mars since 2002 use planetocentric coordinates.

Approximate difference from geographic latitude
φ	reduced φ − β	authalic φ − ξ	rectifying φ − μ	conformal φ − χ	geocentric φ − φ_g
0°	0.00′	0.00′	0.00′	0.00′	0.00′
5°	1.01′	1.35′	1.52′	2.02′	2.02′
10°	1.99′	2.66′	2.99′	3.98′	3.98′
15°	2.91′	3.89′	4.37′	5.82′	5.82′
20°	3.75′	5.00′	5.62′	7.48′	7.48′
25°	4.47′	5.96′	6.70′	8.92′	8.92′
30°	5.05′	6.73′	7.57′	10.09′	10.09′
35°	5.48′	7.31′	8.22′	10.95′	10.96′
40°	5.75′	7.66′	8.62′	11.48′	11.49′
45°	5.84′	7.78′	8.76′	11.67′	11.67′
50°	5.75′	7.67′	8.63′	11.50′	11.50′
55°	5.49′	7.32′	8.23′	10.97′	10.98′
60°	5.06′	6.75′	7.59′	10.12′	10.13′
65°	4.48′	5.97′	6.72′	8.95′	8.96′
70°	3.76′	5.01′	5.64′	7.52′	7.52′
75°	2.92′	3.90′	4.39′	5.85′	5.85′
80°	2.00′	2.67′	3.00′	4.00′	4.01′
85°	1.02′	1.35′	1.52′	2.03′	2.03′
90°	0.00′	0.00′	0.00′	0.00′	0.00′

Astronomical latitude

- A more obscure measure of latitude is the astronomical latitude, which is the angle between the equatorial plane and the normal to the geoid (ie a plumb line). It originated as the angle between horizon and pole star.

Latitude and wealth

It is frequently observed that there is a distinct correlation between latitude and the wealth of nations. The continents along the equator, Africa and South America are the poorest. Even within Africa and South America this can be seen as the nations furthest from the equator are wealthier. In Africa the wealthiest nations are the three on the southern tip of the continent, South Africa, Botswana, and Namibia, and the countries of North Africa. Similarly in Latin America Argentina, Chile and Uruguay have long been the wealthiest. Within Asia, Indonesia, located on the equator, is among the poorest. The wealthiest nations of the world with the highest standard of living tend to be those at the northern extreme of areas open to human habitation, Canada, and the Nordic Countries. Within the wealthy continents, and even within large countries wealth increases with distance from the equator. Southern Europe has long been poorer as has the Southern United States. There have been a number of explanations for this phenomenon. The first to describe and try to assess it was the French philosophe Montesquieu who proposed that cold weather means less blood in the extremities, which makes the flesh less elastic; this gives northerners more strength and makes them less able to relax. This forcing of the blood inward, according to Montesquieu also means more flows through the heart, increasing vitality. These findings have been wholly discredited by modern science.

Evolutionary explanations

One explanation is grounded in evolutionary theory. Some have argued that as humans migrated into higher latitudes and encountered colder weather there, the cold weather forced the evolution of higher group intelligence by forcing inhabitants to perform more intellectually demanding tasks, such as building shelter, fires, and clothing, in order to survive (Lynn, 1991). One study that supports this notion was performed by Beals et al. (1984, p. 309), who found a correlation of 0.62 (p=0.00001) between latitude and cranial capacity in samples worldwide and reported that each degree of latitude was associated with an increase of 2.5 cm³ in cranial volume. Researchers such as J. Philippe Rushton have argued that the association of greater brain size with greater latitude is due to the fact that cold weather imposes on its inhabitants more cognitively demanding tasks such as the need to construct shelter, make clothing, and store food.

Non-evolutionary explanations

Another explanation that is still widely held is that modern technologies and institutions were designed primarily in a small area of north western Europe. Thus agricultural techniques, machines, and medicines were designed to suit a temperate climate. These technologies and models readily spread to areas of similar climate, such as North America and Australia. As these areas also became centres of innovation this bias was further enhanced. Vastly less effort has been put into improving tropical agriculture than temperate because of this. Technologies, from automobiles to power lines are designed for colder drier regions and tend to work far worse in the tropics. In simple words, the life in tropics doesn't create a strong natural urge for new technology development since life conditions in terms of basic body needs are comfortable enough. The colder the weather, the more life necessities are required for survival, which creates a strong motivation for ongoing innovative process. To make a comfortable life farther from tropics requires a more advanced technology. But once the life is comfortable enough, the 'innovation belt' is moving further from equator again. Thus, there exists a vicious cycle of technologies being designed for the wealthy, which makes them more wealthy and thus more able to fund technological development. One piece of evidence for this is that the far north has not always been the wealthiest latitude. Until only a few centuries ago, the wealthiest belt stretched from Southern Europe through the Middle East, northern India and southern China. A dramatic shift in technologies beginning with ocean going ships and culminating in the Industrial Revolution saw the most developed belt move north, in Europe, in China, and in the Americas. Northern Russia became a superpower while southern India became impoverished and colonized. Such dramatic changes argue that the current distribution of wealth is not due to immutable factors such as climate or race. Linked to this explanation is that of disease. The tropics are far more prone to devastating diseases due to their temperature that makes life easier on vectors such as insects and rodents. There has long been a malarial belt spanning the globe; this made human life more difficult. Most notably it was almost impossible for most forms of northern livestock to thrive. These problems have been compounded by the wealth of the north: vastly more research money goes into curing the ailments of northerners. Physiologist Jared Diamond, in his Pulitzer Prize-winning work Guns, Germs, and Steel, made the case that the Europe-Asia land mass is particularly favorable for the transition of societies from hunter-gatherer to farming communities. The continent stretches much further along the same lines of latitude than any of the other continents. As it is much easier to transfer a domesticated species along the same latitude than it is to move it to a warmer or colder climate, any species developed at a particular latitude will be transferred across the continent in a relatively short amount of time. Thus the inhabitants of this continent have a built-in advantage in terms of earlier development of farming, and a greater range of plants and animals from which to choose. He also linked this progression to the development of diseases that were later to threaten the inhabitants of other continents. The close association of people in Europe-Asia with their domesticated animals provided a vector for the rapid transmission of diseases. Inhabitants of lands with few domesticated species were never exposed to the same range of diseases, and so, at least on the American continents, succumbed to diseases introduced from Europe.

References

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-

External links

- [http://www.bcca.org/misc/qiblih/latlong.html Look-up Latitude and Longitude]
- [http://jan.ucc.nau.edu/~cvm/latlon_find_location.html Resources for determining your latitude and longitude]
- [http://geography.about.com/library/howto/htdegrees.htm Convert decimal degrees into degrees, minutes, seconds] - Info about decimal to sexagesimal conversion
- [http://sundials.org/links/local/pages/dd_dms.htm NASS - Convert degrees/minutes/seconds to decimal degrees and vice versa] - JavaScript version
- [http://www.marinewaypoints.com/learn/greatcircle.shtml Distance calculation based on latitude and longitude] - JavaScript version
- [http://www.cia.gov/cia/publications/factbook/reference_maps/pdf/political_world.pdf Zoomable version of the map] (pdf) Category:Navigation Category:Angle ja:緯度 th:ละติจูด

Oceanography

Oceanography (from Ocean + Greek γράφειν = write), also called oceanology or marine science is the study of the Earth's oceans and seas. Oceanographers study a diverse range of topics such as plate tectonics to ocean currents to marine organisms. These wide range of topics are reflective of the types of backgrounds that oceanographers come from: Chemistry, Biology, Physics and Geology.

Branches of Oceanography

There are generally five branches of oceanography:
- Biological oceanography or marine biology, the study of the plants and animals (biota) of the oceans and their ecological interaction;
- Chemical oceanography, the study of the chemistry of the ocean;
- Geological oceanography, the study of the geology of the ocean floor including plate tectonics;
- Meteorologic oceanography, the study of the interactions of the atmosphere and the ocean in the hydrosphere; and
- Physical oceanography, the study of the physical attributes of the ocean (such as its temperature-salinity structure, waves, and currents).
The five branches tend to stem from the fact that many oceanographers are trained in the exact sciences and then specialise in oceanography.

History of oceanography

exact sciences Early exploration of the oceans was limited to its surfaces and the few creatures that fishermen brought up in nets, but when Bougainville and Cook carried out their explorations in the South Pacific, the seas themselves formed part of the reports. James Rennell wrote the first scientific textbooks about currents in the Atlantic and Indian ocean during the late 18th and at the beginning of 19th century. Sir James Clark Ross took the first modern sounding in deep sea in 1840, and Charles Darwin published a paper on reefs and the formation of atolls, but the existence of the steep slope beyond the continental shelves was not discovered until 1849. Matthew Fontaine Maury's Physical Geography of the Sea, 1855 was the first textbook of oceanography. Laying of North Atlantic telegraph cable confirmed the presence of a mid-ocean ridge. After the middle of the 19th century, as scientific societies were processing a flood of new terrestrial botanical and zoological information, European natural historians began to sense the lack of more than anecdotal knowledge of the oceans. The beginnings of oceanography as a quantifiable science really began in 1872, when Charles Wyville Thompson and John Murray set out on the Challenger expedition (1872-76). Other European and American nations soon sent out scientific expeditions (as did private individuals and institutions), and institutes dedicated to the study of oceanography were created. The four top ones in the United States are the Scripps Institution of Oceanography, Woods Hole Oceanographic Institution, Lamont-Doherty Earth Observatory, and University of Washington's School of Oceanography. In Britain, a major new research institution is the Southampton Oceanography Centre. The first international organization of oceanography was created in 1901 as the International Council for the Exploration of the Sea. In 1921 the International Hydrographic Bureau (IHB) was formed in Monaco. Later, in 1966, the U.S. Congress created the National Council for Marine Resources and Engineering Development, which was in charge of exploring and studying all aspects of Oceanography. It also enabled the National Science Foundation to give grant money to people doing studies in the field of oceanography.

Notable Oceanographers

- Jacques Cousteau
- V. Walfrid Ekman
- Evan Forde
- Gotthilf Hempel
- Charles David Keeling
- Walter Munk
- Henry Stommel
- Harald Sverdrup

External link

- [http://www.gesource.ac.uk/timeline_Oceanography.html Timeline of Oceanography]
- [http://ioc.unesco.org/goos/ Global Ocean Observing System (GOOS)]
- [http://www.oceanographers.net Oceanographers Net (Online portal for the Oceanographic community)]
- [http://www.tos.org/ The Oceanography Society]
- [http://www.soc.soton.ac.uk/ National Oceanography Centre, Southampton] ko:해양학 ja:海洋学

Gulf

- A gulf or bay is a part of a lake or ocean that extends so that it is surrounded by land on three sides. See headlands and bays for more on this.
- Gulf is also a novella by Robert A. Heinlein.
- A company, see Gulf Oil

Basalt

]] Basalt is a common gray to black volcanic rock. It is usually fine-grained due to rapid cooling of lava on the Earth's surface. It may be porphyritic containing larger crystals in a fine matrix. Basalt in the tops of subaerial lava flows and cinder cones will often be highly vesiculated, imparting a lightweight "frothy" texture to the rock. The term basalt is at times applied to shallow intrusive rocks with a composition typical of basalt, but rocks of this composition with a phaneritic (coarse) groundmass should generally be referred to as diabase or gabbro. The crustal portions of oceanic tectonic plates are predominantly made of basalt. Unweathered basalt is frequently black to greenish-black in color, characterized by a preponderance of calcic plagioclase feldspars and pyroxene together with minor amounts of accessory minerals such as olivine. Basaltic cinders are often red. Glass may be present, particularly as rinds on rapidly chilled surfaces of lava flows, and is commonly (but not exclusively) associated with underwater eruptions. Amygdaloidal structure is common in relic vesicles and beautifully crystallized species of zeolites, quartz or calcite are frequently found. The lava flows of the Deccan Traps in India, the Columbia River Plateau of Washington and Oregon states in the United States, as well as the Triassic lavas of eastern North America are basalts. Perhaps the most famous basalt flow in the world is the Giant's Causeway on the northern coast of Ireland, in which the vertical joints form hexagonal columns and give the impression of having been artificially constructed. Pliny used the word basalt and it is said to have had an Ethiopian origin, meaning a black stone.

Pillow lava

Ethiopia When basalt erupts underwater or flows into the sea, the cold water quenches the surface and the lava forms a distinctive pillow shape, then the hot lava breaks through to form another pillow. This pillow texture is very common in underwater basaltic flows and pillow basalts are diagnostic of an underwater eruption environment when found in ancient rocks. Pillows typically consist of a fine-grained core with a glassy crust and have radial jointing. Size of individual pillows vary from 10 cm up to 6 m.

Lunar basalt

The dark areas visible on Earth's moon, the lunar mares, are plains of basalt and gabbro, and basalt Moon samples were brought to Earth by the astronauts of the Apollo program.

Types of basalt

- Tholeiitic basalt is relatively rich in silica and poor in sodium. Included in this category are most basalts of the ocean floor, most large oceanic islands, and continental flood basalts such as the Columbia River Plateau. Pyroxene (augite and orthopyroxene or pigeonite), calcium rich plagioclase, and magnetite are common minerals. Contains interstitial quartz or tridymite plus minor olivine.
- Olivine tholeiite has augite and orthopyroxene or pigeonite with abundant olivine. Olivine may have rims of pyroxene.
- High alumina basalt has typically only augite with common olivine. Has greater than 17% alumina (Al₂O₃) and less titanium than tholeites.
- Alkaline basalt is relatively poor in silica and rich in sodium. It has augite, olivine, feldspathoids, and may have alkali feldspar and phlogopite.

References

# #

External links

- [http://www.geology.sdsu.edu/how_volcanoes_work/lava_water.html Lava - water interface]
- [http://volcanoes.usgs.gov/Products/Pglossary/PillowLava.html Pillow lava USGS] Category:Igneous rocks Category:Rocks Category:Volcanology ko:현무암 ja:玄武岩

Black Sea

:For the XTC album, see Black Sea (album). Black Sea (album) Black Sea (album)]] The Black Sea (known as the Euxine Sea in antiquity) is an inland sea between southeastern Europe and Asia Minor. It is connected to the Mediterranean Sea by the Bosporus and the Sea of Marmara, and to the Sea of Azov by the Strait of Kerch. There is a net inflow of seawater through the Bosporus, 200 km³ per year. There is an inflow of freshwater from the surrounding areas, especially central and middle-eastern Europe, totalling 320 km³ per year. The most important river entering the Black Sea is the Danube. The Black Sea has an area of 422,000 km² and a maximum depth of 2210 m. Countries bordering on the Black Sea are Turkey, Bulgaria, Romania, Ukraine, Russia, and Georgia. The Crimean peninsula is a Ukrainian autonomous republic. Important cities along the coast include: Istanbul (formerly Constantinople and Byzantium), Burgas, Varna, Constanţa, Yalta, Odessa, Sevastopol, Kerch, Novorossiysk, Sochi, Sukhumi, Poti, Batumi, Trabzon, Samsun.

Name

An equivalent of the name "Black Sea", Μαύρη Θάλασσα, cannot be traced to an earlier date than the 13th century. Strabo (1.2.10) reports that in antiquity, the Black Sea was often just called "the Sea" (pontos), just like Homer was often simply called "the Poet". For the most part, Graeco-Roman tradition refers to the Black Sea as Εύξεινος Πόντος Euxeinos Pontos "Hospitable sea". This is a euphemism replacing an earlier Pontos Axeinos "Inhospitable Sea", first attested in Pindar (early 5th century BC). Strabo (7.3.6) thinks that the Black Sea was called "inhospitable" before Greek colonialization, because it was difficult to navigate, and because its shores were inhabited by savage tribes, and that the name was changed to "hospitable" after the Milesians had colonized, as it were making it part of the Greek civilization. It is, however, likely, that the name Axeinos arose by popular etymology, either from an Iranian axaina "dark", or from Ascanian, i.e. Phrygian. If from axaina "dark", the designation "Black Sea" would, after all, go back to Antiquity. The motive for the name may be an ancient assignment of colours to the direction of the compass, "black" referring to the north, and "red" referring to the south. Herodotus on one occasion uses Red Sea and "Southern Sea" interchangeably. Modern names of the Sea are universally translations of Μαύρη Θάλασσα "Black Sea", Turkish Kara Deniz, Russian Черное Море, Bulgarian Cherno More, Черно Море, Geogian შავი ზღვა, shavi zghva, Ukrainian Chorne More, Romanian Marea Neagră, Laz Ucha Zuğa (or simple Zuğa "Sea"), Ubykh .

Geology

The Black Sea is the largest anoxic, or oxygen-free, marine system. This is a result of the great depth of the sea and the relatively high salinity (and therefore density) of the water at depth; freshwater and seawater mixing is limited to the uppermost 100 to 150 m, with the water below this interface (called the pycnocline) being exchanged only once every thousand years. There is therefore no significant gas exchange with the surface, and as a result

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Black Sea

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