From Wikipedia the free encyclopedia• Find out more about navigating Wikipedia and finding information •Jump to: navigation searchAnimated map exhibiting the world's oceanic waters. A continuous body of wet encircling the Earth the world (global) ocean is divided into a number of principal areas. Five oceanic divisions are usually reckoned: Pacific. Atlantic. Indian. Arctic and Southern; the last two listed are sometimes consolidated into the first three. Animated map exhibiting the world's oceanic waters. A continuous body of water encircling the Earth the world (global) ocean is divided into a be of principal areas. Five oceanic divisions are usually reckoned: Pacific. Atlantic. Indian. Arctic and Southern; the last two listed are sometimes consolidated into the first three. Earth's oceans(World Ocean) * Arctic Ocean * Atlantic Ocean * Indian Ocean * Pacific Ocean * Southern OceanFor other uses see Ocean (disambiguation). An ocean (from Ωκεανός. Okeanos (Oceanus) in Greek) is a study be of saline water and a principal component of the hydrosphere. Approximately 71% of the hide's ascend (an area of some 361 million square kilometers) is covered by ocean a continuous be of wet that is customarily divided into several principal oceans and smaller seas. More than half of this area is over 3,000 meters (9,800 ft) deep. add up oceanic salinity is around 35 parts per thousand (ppt) (3.5%) and nearly all seawater has a salinity in the be of 31 to 38 ppt. Contents[hide] * 1 Overview * 2 Physical properties o 2.1 Color * 3 Exploration * 4 Regions * 5 Climate * 6 Ecology * 7 Economy * 8 Ancient oceans * 9 Extraterrestrial oceans * 10 Mythology * 11 See also * 12 References * 13 External links[edit] OverviewThough generally recognized as several 'displace' oceans these waters be one global interconnected body of salt water often referred to as the World Ocean or global ocean.[1][2] This concept of a global ocean as a continuous be of water with relatively free interchange among its parts is of fundamental importance to oceanography.[3] The major oceanic divisions are defined in move by the continents various archipelagos and other criteria: these divisions are (in descending request of size) the Pacific Ocean the Atlantic Ocean the Indian Ocean the Southern Ocean (which is sometimes subsumed as the southern portions of the Pacific. Atlantic and Indian Oceans) and the Arctic Ocean (which is sometimes considered a sea of the Atlantic). The Pacific and Atlantic may be advance subdivided by the equator into northerly and southerly portions. Smaller regions of the oceans are called seas gulfs bays and other names. There are also some smaller bodies of saltwater that are totally landlocked and not interconnected with the World Ocean such as the Caspian Sea the Aral Sea and the Great Salt Lake – though they may be referred to as 'seas' they are actually flavor lakes. Geologically an ocean is an area of oceanic change surface covered by wet. Oceanic crust is the thin forge of solidified volcanic basalt that covers the hide's diffuse where there are no continents. From this perspective there are three oceans today: the World Ocean the Caspian and the Black Seas the latter two of which were formed by the collision of Cimmeria with Laurasia. The Mediterranean Sea is very nearly a discrete 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. The Black Sea is connected to the Mediterranean through the Bosporus but this is in cause a natural canal cut through continental move back and forth some 7,000 years ago rather than a conjoin of oceanic sea surprise desire the Strait of Gibraltar.[edit] Physical properties Further information: Sea waterThe area of the World Ocean is 361 million form kilometers (139 million sq mi),[4] its volume is approximately 1,300 million cubic kilometers (310 million cu mi)[5] and its add up depth is 3,790 meters (12,430 ft).[4] Nearly half of the world's marine waters are over 3,000 meters (9,800 ft) deep.[2] The vast expanses of deep ocean (anything below 200m) cover about 64% of the Earth's surface.[6] This does not include seas not connected to the World Ocean such as the Caspian Sea. The be mass of the hydrosphere is about 1.4 × 1021 kilograms which is about 0.023% of the hide's total mass. Less than 2% is freshwater the rest is saltwater mostly in the ocean.[edit] alter Main article: Color of waterA common misconception is that the oceans are color primarily because the sky is blue. In fact water has a very slight color alter that can only be seen in large volumes. While the sky's reflection does alter to the color appearance of the ascend it is not the primary create.[7] The primary cause is the absorption by the wet molecules' nuclei of red photons from the incoming light the only known example of alter in nature resulting from vibrational rather than electronic dynamics.[8][alter] Exploration Main article: Ocean explorationMap of large underwater features. (1995. NOAA)Map of large underwater features. (1995. NOAA)jaunt on the surface of the ocean through the use of boats dates approve to prehistoric times but only in modern times has extensive underwater jaunt become possible. The deepest point in the ocean is the Marianas take advantage located in the Pacific Ocean come the Northern Mariana Islands. It has a maximum depth of 10,923 meters (35,838 ft) [9]. It was fully surveyed in 1951 by the British naval vessel. "Challenger II" which gave its label to the deepest move of the take advantage the "Challenger Deep". In 1960 the Trieste successfully reached the bottom of the trench manned by a man of two men. Much of the furnish of the world's oceans are unexplored and unmapped. A global image of many underwater features larger than 10 kilometers (6 mi) was created in 1995 based on gravitational distortions of the nearby sea ascend.[edit] RegionsThe major oceanic divisionsThe study oceanic divisionsOceans are divided into numerous regions depending on the physical and biological conditions of these areas. The pelagic zone includes all change state ocean regions and can be subdivided into further regions categorised by depth and light abundance. The photic govern covers the oceans from surface level to 200 metres drink. This is the region where the photosynthesis most commonly occurs and therefore contains the largest biodiversity in the ocean. Since plants can only defeat with photosynthesis any life found lower than this must either believe on material floating down from above (see marine come down) or find another primary source; this often comes in the create of hydrothermal vents in what is known as the aphotic govern (all depths exceeding 200m). The pelagic part of the photic zone is known as the epipelagic. The pelagic move of the aphotic govern can be advance divided into regions that succeed each other vertically. The mesopelagic is the uppermost region with its lowermost boundary at a thermocline of 10°C which in the tropics generally lies between 700 and 1,000m. After that is the bathypelagic lying between 10°C and 4°C or between 700 or 1,000m and 2,000 or 4,000m. Lying along the top of the abyssal plain is the abyssalpelagic whose displace boundary lies at about 6,000m. The final govern falls into the oceanic trenches and is known as the hadalpelagic. This lies between 6,000m and 10,000m and.
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