Tuesday, May 14, 2013

Deep sea&Deep sea fish

http://www.all-keyboard.com/,http://www.keyboards-shop.com/,http://www.laptop-fan-shop.com/,http://www.laptopkeyboard-shop.com/ The deep sea, or deep layer,[1] is the lowest layer in the ocean, existing below the thermocline and above the seabed, at a depth of 1000 fathoms (1800 m) or more. Little or no light penetrates this part of the ocean and most of the organisms that live there rely for subsistence on falling organic matter produced in the photic zone. Sony VAIO PCG-3B1M Battery For this reason scientists once assumed that life would be sparse in the deep ocean but virtually every probe has revealed that, on the contrary, life is abundant in the deep ocean. From the time of Pliny until the expedition in the ship Challenger between 1872 and 1876 to prove Pliny wrong; Sony VAIO PCG-3C1T Battery its deep-sea dredges and trawls brought up living things from all depths that could be reached. Yet even in the twentieth century scientists continued to imagine that life at great depth was insubstantial, or somehow inconsequential. The eternal dark, the almost inconceivable pressure, and the extreme cold that exist below one thousand meters were, they thought, so forbidding as to have all but extinguished life. Sony VAIO PCG-3D1M Battery The reverse is in fact true....(Below 200 meters) lies the largest habitat on earth. In 1960 the Bathyscaphe Trieste descended to the bottom of the Mariana Trench near Guam, at 35,798 feet or 6.77 miles (10,911 meters), the deepest spot in any ocean. If Mount Everest were submerged there, its peak would be more than a mile beneath the surface. Sony VAIO PCG-3G2M Battery At this great depth a small flounder-like fish was seen moving away from the bathyscaphe's spotlight. The Triestewas retired and for a while the Japanese remote-operated vehicle (ROV) Kaikō was the only vessel capable of reaching this depth. It was lost at sea in 2003. In May and June 2009, the hybrid-ROV (HROV) Nereus returned to the Challenger Deep for a series of three dives to depths exceeding 10900 meters. Sony VAIO PCG-5R1M Battery It has been suggested that more is known about the Moon than the deepest parts of the ocean.[2] Until the late 1970s little was known about the extent of life on the deep ocean floor but the discovery of thriving colonies of shrimps and other organisms around hydrothermal vents changed that. Sony VAIO PCG-7141M Battery Before the discovery of the undersea vents, it had been accepted that almost all life on earth obtained its energy (one way or another) from the sun. The new discoveries revealed groups of creatures that obtained nutrients and energy directly from thermal sources and chemical reactions associated with changes to mineral deposits. Sony VAIO PCG-7143M Battery These organisms thrive in completely lightless and anaerobic environments, in highly saline water that may reach 300 °F (150 °C), drawing their sustenance from hydrogen sulfide, which is highly toxic to almost all terrestrial life. The revolutionary discovery that life can exist under these extreme conditions changed opinions about the chances of there being life elsewhere in the universe. Sony VAIO PCG-7151M Battery Scientists now speculate that Europa, one of Jupiter's moons, may be able to support life beneath its icy surface, where there is evidence[3] of a global ocean of liquid water. Natural light does not penetrate the deep ocean, with the exception of the upper parts of the mesopelagic. Sony VAIO PCG-7154M Battery Since photosynthesis is not possible, plants cannot live in this zone. Since plants are the primary producers of almost all of earth's ecosystems, life in this area of the ocean must depend on energy sources from elsewhere. Except for the areas close to the hydrothermal vents, this energy comes from organic material drifting down from the photic zone. Sony VAIO PCG-7162M Battery Because pressure in the ocean increases by about 1 atmosphere for every 10 meters of depth, the amount of pressure experienced by many marine organisms is extreme. Until recent years, the scientific community lacked detailed information about the effects of pressure on most deep sea organisms because the specimens encountered arrived at the surface dead or dying, Sony VAIO PCG-7181M Battery and weren't observable at the pressures at which they lived. With the advent of traps that incorporate a special pressure-maintaining chamber, undamaged larger metazoan animals have been retrieved from the deep sea in good condition. Salinity is remarkably constant throughout the deep sea. There are some minor differences in salinity, but none that are ecologically significant, except in the Mediterranean & Red seas. Sony VAIO PCG-41112M Battery The two areas of greatest and most rapid temperature change in the oceans are the transition zone between the surface waters and the deep waters, the thermocline, and the transition between the deep-sea floor and the hot water flows at the hydrothermal vents. Thermoclines vary in thickness from a few hundred meters to nearly a thousand meters. Sony VAIO PCG-7153M Battery Below the thermocline, the water mass of the deep ocean is cold and far more homogeneous. Thermoclines are strongest in the tropics, where the temperature of the epipelagic zone is usually above 20°C. From the base of the epipelagic, the temperature drops over several hundred meters to 5 or 6°C at 1,000 meters. Sony VAIO PCG-71312M Battery It continues to decrease to the bottom, but the rate is much slower. Below 3,000 to 4,000 m, the water is isothermal.At any given depth, the temperature is practically unvarying over long periods of time. There are no seasonal temperature changes, nor are there any annual changes. No other habitat on earth has such a constant temperature. Sony VAIO PCG-7144M Battery Hydrothermal vents are the direct contrast with constant temperature. In these systems, the temperature of the water as it emerges from the "black smoker" chimneys may be as high as 400°C (it is kept from boiling by the high hydrostatic pressure) while within a few meters it may be back down to 2 - 4°C. Sony VAIO PCG-7191L Battery Regions below the epipelagic are divided into further zones, beginning with the mesopelagic which spans from 200 to 1000 meters below sea level, where a little light penetrates while still being insufficient for primary production. Below this zone the deep sea proper begins, consisting of the aphotic bathypelagic,abyssopelagic and hadopelagic. Sony VAIO PCG-3C1M Battery Food consists of falling organic matter known as 'marine snow' and carcasses derived from the productive zone above, and is scarce both in terms of spatial and temporal distribution. Instead of relying on gas for their buoyancy, many species have jelly-like flesh consisting mostly of glycosaminoglycans, which has very low density. Sony VAIO PCG-3F1M Battery It is also common among deep water squid to combine the gelatinous tissue with a flotation chamber filled with a coelomic fluid made up of the metabolic waste productammonium chloride, which is lighter than the surrounding water. The midwater fish have special adaptations to cope with these conditions—they are small, usually being under 25 centimetres (10 in); Sony VAIO PCG-3H1M Battery they have slow metabolismsand unspecialized diets, preferring to sit and wait for food rather than waste energy searching for it. They have elongated bodies with weak, watery muscles andskeletal structures. They often have extendable, hinged jaws with recurved teeth. Sony VAIO PCG-3J1M Battery Because of the sparse distribution and lack of light, finding a partner with which to breed is difficult, and many organisms are hermaphroditic. Because light is so scarce, fish often have larger than normal, tubular eyes with only rod cells. Their upward field of vision allows them to seek out the silhouette of possible prey. Sony VAIO PCG-8141M Battery Prey fish however also have adaptations to cope withpredation. These adaptations are mainly concerned with reduction of silhouette, a form of camouflage. The two main methods by which this is achieved are reduction in the area of their shadow by lateral compression of the body, and counter illumination via bioluminescence. Sony VAIO PCG-8161M Battery This is achieved by production of light from ventral photophores, which tend to produce such light intensity to render the underside of the fish of similar appearance to the background light. For more sensitive vision in low light, some fish have a retroreflector behind the retina. Sony VAIO PCG-3C2M Battery Flashlight fish have this plus photophores, which combination they use to detect eyeshine in other fish (see Tapetum lucidum).Organisms in the deep sea are almost entirely reliant upon sinking living and dead organic matter which falls at approximately 100 meters per day.[6] In addition, only about 1-3% of the production from the surface reaches the sea bed mostly in the form of marine snow. Sony VAIO PCG-5N2M Battery Larger food falls, such as whale carcasses, also occur and studies have shown that these may happen more often than currently believed. There are many scavengers that feed primarily or entirely upon large food falls and the distance between whale carcasses is estimated to only be 8 kilometers. Sony VAIO PCG-5P1M Battery In addition, there are a number of filter feeders that feed upon organic particles using tentacles, such as Freyella elegans.[8] Marine bacteriophages play an important role in cycling nutrients in deep sea sediments. They are extremely abundant (between 5x1012 and 1x1013 phages per square meter) in sediments around the world. Sony VAIO PCG-5S1M Battery There are a number of species that do not primarily rely upon dissolved organic matter for their food and these are found at hydrothermal vents. One example is the symbiotic relationship between the tube worm Riftia and chemosynthetic bacteria. It is this chemosynthesis that supports the complex communities that can be found around hydrothermal vents. Sony VAIO PCG-9Z1M Battery These complex communities are one of the only ecosystems on the planet that do not rely upon sunlight for the supply of energy. The deep sea is an environment completely unfriendly to humankind, and it should come as no surprise that it represents one of the least explored areas on Earth. Sony VAIO PCG-7171M Battery Pressures even in the mesopelagic become too great for traditional exploration methods, demanding alternative approaches for deep sea research. Baited camera stations, small manned submersibles and ROVs (remotely operated vehicles) are three methods utilized to explore the ocean's depths. Sony VAIO PCG-7186M Battery Because of the difficulty and cost of exploring this zone, current knowledge is limited. Pressure increases at approximately one atmosphere for every 10 meters meaning that some areas of the deep sea can reach pressures of above 1,000 atmospheres. This not only makes great depths very difficult to reach without mechanical aids, Sony VAIO PCG-81112M Battery but also provides a significant difficulty when attempting to study any organisms that may live in these areas as their cell chemistry will be adapted to such vast pressures. Deep-sea exploration is the investigation of physical, chemical, and biological conditions on the sea bed, for scientificor commercial purposes. Sony VAIO PCG-31311M Battery Deep-sea exploration is considered as a relatively recent human activity compared to the other areas of geophysical research, as the depths of the sea have been investigated only during comparatively recent years. The ocean depths still remain as a largely unexplored part of the planet, and form a relatively undiscovered domain. Sony VAIO PCG-8152M Battery In general, modern scientific Deep-sea exploration can be said to have begun when French scientist Pierre Simon de Laplaceinvestigated the average depth of the Atlantic ocean by observing tidal motions registered on Brazilian and African coasts. He calculated the depth to be 3,962 m (13,000 ft), a value later proven quite accurate by soundings measurement. Sony VAIO PCG-31111M Battery Later on, with increasing demand for submarine cables installment, accurate soundings was required and the first investigations of the sea bottom were undertaken. First deep-sea life forms were discovered in 1864 when Norwegian researchers obtained a sample of a stalked crinoid at a depth of 3,109 m (10,200 ft). Sony VAIO PCG-61111M Battery The British Government sent out the Challenger expedition (a ship called the HMS Challenger) in 1872 which discovered 715 new genera and 4,417 new species of marine organisms over the space of 4 years.[1] The first instrument used for deep-sea investigation was the sounding weight, used by British explorer Sir James Clark Ross.[2] Sony VAIO PCG-51112M Battery With this instrument, he reached a depth of 3,700 m (12,140 ft) in 1840.[3] The Challenger expedition used similar instruments called Baillie sounding machines to extract samples from the sea bed.[4] In 1960, Jacques Piccard and US Navy Lieutenant Donald Walsh descended in the bathyscaphe Trieste into the Mariana Trench, Sony VAIO PCG-51211M Battery the deepest part of the world's oceans, to make the deepest dive in history: 10,915 meters (35,810 ft).[5] On 25 March 2012, filmmaker James Cameron descended into the deepest part of the Mariana Trench and, for the first time, is expected to have filmed and sampled the bottom. Sony VAIO PCG-51212M Battery Throughout history, scientists have relied on a number of instruments to measure, map, and observe the ocean's depths. One of the first instruments used to examine the seafloor was the sounding weight. Ancient Viking sailors took measurements of sea depth and sampled seafloor sediments with this instrument, Sony VAIO PCG-41111M Battery which consisted of a lead weight with a hollow bottom attached to a line. Once the weight reached the sea bottom and collected a sample of the seabed, the line was hauled back on board ship and measured in fathom.[11] Cornelius Drebbel, a Dutch architect, is generally given credit for construction of the first submarine. Sony VAIO PCG-41111V Battery His submersible boat consisted of a wooden frame sheathed in animal skin. Oars, with its openings were sealed with tight-fitting leather flaps, extended out the sides to propel the craft through the water, at depths up to 4.6 meters (15 ft). Drebel tested his submarine in the Thames River in England in sometime between 1620 and 1624. Sony VAIO PCG-61412V Battery It is believed that King James I may have enjoyed a short ride in the craft.[12] However, the nature of the deep ocean remained an unrevealed mystery until the mid-19th century. Scientists and artists alike imagined the deep sea as a lifeless soup of placid water. French author Jules Verne, Sony VAIO PCG-71112M Battery who helped pioneer the science-fiction genre, portrayed the deep ocean as contained in a bowl of static rock in his “Twenty Thousand Leagues under the Sea”. By the late 1860s, controversial modern scientific theories, the origin of life by evolution and the enormity of geologic time had created a foundation of scientific curiosity and provoked a rising interest in marine exploration. Sony VAIO PCG-81111V Battery The Royal Society ofEngland thus initiated an ambitious oceanographic mission to expand a scarce collection of existing marine data that included Charles Darwin's observations during the voyage of the HMS Beagle (1831–1836), a bathymetric chart created by U.S. Navy Lt. Matthew Maury to aid installation of the first trans-continent telegraph cables in 1858, and a few examples of deep marine creatures.[13] Sony VAIO PCG-81111V Battery From 1872 to 1876, a landmark ocean study was carried out by British scientists aboard HMS Challenger, a sailing vessel that was redesigned into a laboratory ship. The HMS Challenger expedition covered 127,653 km (68,890 nautical miles), and shipboard scientists collected hundreds of samples, hydrographic measurements, and specimens of marine life. Sony VAIO PCG-81212M Battery They are also credited with providing the first real view of major seafloor features such as the deep ocean basins. They discovered more than 4,700 new species of marine life, including deep-sea organisms.[14] Deep-sea exploration advanced considerably in the 1900s thanks to a series of technological inventions, Sony VAIO PCG-81212V Battery ranging from sonar system to detect the presence of objects underwater through the use of sound to manned deep-diving submersibles such as DSV Alvin. Operated by the Woods Hole Oceanographic Institution, Alvin is designed to carry a crew of three people to depths of 4,000 meters (13,124 ft). Sony VAIO PCG-51111M Battery The submarine is equipped with lights, cameras, computers, and highly maneuverable robotic arms for collecting samples in the darkness of the ocean's depths.[15] However, the voyage to the ocean bottom is still a challenging experience. Scientists are working to find ways to study this extreme environment from the shipboard. Sony VAIO VPCS13X9E/B battery With more sophisticated use of fiber optics, satellites, and remote-control robots, scientists one day may explore the deep sea from a computer screen on the deck rather than out of a porthole. The sounding weight, one of the first instruments used for the sea bottom investigation, Sony VAIO VPCS12V9E/B battery was designed as a tube on the base which forced the seabed in when it hit the bottom of the ocean. British explorer Sir James Clark Ross fully employed this instrument to reach a depth of 3,700 m (12,140 ft) in 1840.[2][17] The sounding weights used on the HMS Challenger were slightly advanced called "Baillie sounding machine". Sony VAIO VPCS12V9E/B battery The British researchers used wire-line soundings to investigate sea depths and collected hundreds of biological samples from all the oceans except the Arctic. Also used on the HMS Challenger were dredges and scoops, suspended on ropes, with which samples of the sediment and biological specimens of the seabed could be obtained.[2] Sony VAIO VPCF13M8E/B battery A more advanced version of the sounding weight is the gravity corer. The gravity corer allows researchers to sample and study sediment layers at the bottom of oceans. The corer consists of an open-ended tube with a lead weight and a trigger mechanism that releases the corer from its suspension cable when the corer is lowered over the seabed and a small weight touches the ground. Sony VAIO VPCF13Z0E/B battery The corer falls into the seabed and penetrates it to a depth of up to 10 m (33 ft). By lifting the corer, a long, cylindrical sample is extracted in which the structure of the seabed’s layers of sediment is preserved. Recovering sediment cores allows scientists to see the presence or absence of specific fossils in the mud that may indicate climate patterns at times in the past, Sony VAIO VPCM13M1E/L battery such as during the ice ages. Samples of deeper layers can be obtained with a corer mounted in a drill. The drilling vessel JOIDES Resolution is equipped to extract cores from depths of as much as 1,500 m (4900 ft) below the ocean bottom. (See Ocean Drilling Program). Sony VAIO VPCM13M1E/W battery Echo-sounding instruments have also been widely used to determine the depth of the sea bottom since World War II. This instrument is used primarily for determining the depth of water by means of an acoustic echo. A pulse of sound sent from the ship is reflected from the sea bottom back to the ship, Sony VAIO VPCF22M1E battery the interval of time between transmission and reception being proportional to the depth of the water. By registering the time lapses between outgoing and returning signals continuously on paper tape, a continuous mapping of the seabed is obtained. The majority of the ocean floor has been mapped in this way. Sony VAIO VPCF11M1E/H battery In addition, high-resolution television cameras, thermometers, pressure meters, and seismographs are other notable instruments for deep-sea exploration invented by the technological advance. These instruments are either lowered to the sea bottom by long cables or directly attached to submersible buoys. Sony VAIO VPCF13M0E/B battery Deep-sea currents can be studied by floats carrying an ultrasonic sound device so that their movements can be tracked from aboard the research vessel. Such vessels themselves are equipped with state -of-art navigational instruments, such as satellite navigation systems, and global positioning systems that keep the vessel in a live position relative to a sonar beacon on the bottom of the ocean. Sony VAIO VPCYB2M1E battery Because of the high pressure, the depth to which a diver can descend without special equipment is limited. The deepest recorded made by a skin diver is 127 meters (417 ft).[14] The deepest record made by a scuba diver is not much deeper, at 145 meters (475 ft). Sony VAIO VPCYB3V1E battery Revolutionary new diving suits, such as the "JIM suit," allows divers to reach depths up to approximately 600 meters (2,000 ft).[20] Some additional suits feature thruster packs that boost a diver to different locations underwater.[21] To explore even deeper depths, deep-sea explorers must rely on specially constructed steel chambers to protect them. Sony VAIO VPCY11M1E battery The American explorer William Beebe, also a naturalist from Columbia University in New York, was the designer of the first practical bathysphere to observe marine species at depths that could not be reached by a diver.[22] The Bathysphere, a spherical steel vessel, was designed by Beebe and his fellow engineer Otis Barton, an engineer at Harvard University. Sony VAIO VPCS12L9E/B battery In 1930 Beebe and Barton reached a depth of 435 m (about 1425 ft), and 923 m (3028 ft) in 1934. The potential danger was that if the cable broke, the occupants could not return to the surface. During the dive, Beebe peered out of a porthole and reported his observations by telephone to Barton who was on the surface. Sony VAIO VPCF11S1E/B battery In 1948, Swiss physicist Auguste Piccard tested a much deeper-diving vessel he invented called the bathyscaphe, a navigable deep-sea vessel with its gasoline-filled float and suspended chamber or gondola of spherical steel.[22] On an experimental dive in the Cape Verde Islands, Sony VAIO VPCYB3V1E/R Battery his bathyscaphe successfully withstood the pressure on it at 1,402 meters (4,600 ft), but its body was severely damaged by heavy waves after the dive. In 1954, with this bathyscaphe, Piccard reached a depth of 4,000 m (13,125 ft).[22] In 1953, his son Jacques Piccard joined in building new and improved bathyscaphe Trieste, which dived to 3,139 meters (10,300 ft) in field trials.[22] Sony VAIO VPCF23P1E Battery The U.S. Navy acquired Trieste in 1958 and equipped it with a new cabin to enable it to reach deep ocean trenches.[5] In 1960, Jacques Piccard and Navy Lieutenant Donald Walsh descended in Trieste to the deepest known point on Earth - the Challenger Deep in the Mariana Trench, successfully making the deepest dive in history: 10,915 meters (35,810 ft).[5] Sony VAIO VPCF23N1E Battery An increasing number of occupied submersibles are now employed around the world. The American-built DSV Alvin that is operated by the Woods Hole Oceanographic Institution, is a three-person submarine that can dive to about 3,600 m (12,000 ft) and is equipped with a mechanical manipulator to collect bottom samples.[25] Sony VAIO VPCY21S1E/L Battery Alvin made its first test dive in 1964, and has performed more than 3,000 dives to average depths of 1,829 meters (6,000 ft). Alvin has also involved in a wide variety of research projects, such as one where giant tube worms were discovered on the Pacific Ocean floor near the Galápagos Islands. Sony VAIO VPCY21S1E/G battery One of the first unmanned deep sea vehicles was developed by the University of California with a grant from the Alan Hancock Foundation in the early 1950s to develop a more economical method of taking photos miles under the sea with an unmanned steel high pressure 3,0000 lb sphere called a benthograph which contained a camera and strobe light. Sony VAIO VPCF24M1E battery The original benthograph built by USC was very successful in taking a series of underwater photos till it became wedged between some rocks and could not be retrieved. [26] ROVs, or Remote Operated Vehicles, are seeing increasing use in underwater exploration. Sony VAIO VGN-NW21EF/S Battery These submersibles are piloted through a cable which connects to the surface ship, and they can reach depths of up to 6,000 meters. New developments in robotics have also led to the creation of AUVs, or Autonomous Underwater Vehicles. The robotic submarines are programmed in advance, and receive no instruction from the surface. Sony VAIO VGN-NW21JF Battery HROV combine features of both ROVs and AUV, operating independently or with a cable.[27][28] Argo was employed in 1985 to locate the wreck of the RMS Titanic; the smaller Jason was also used to explore the ship wreck. In 1974 the Alvin (operated by the Woods Hole Oceanographic Institution and the (Deep Sea Place Research Center), Sony VAIO VGN-NW21MF Battery the French bathyscaphe Archimède, and the French diving saucer Cyane, assisted by support ships and the Glomar Challenger, explored the great rift valley of the Mid-Atlantic Ridge, southwest of theAzores. About 5,200 photographs of the region were taken, and samples of relatively young solidified magma were found on each side of the central fissure of the rift valley, Sony VAIO VGN-NW21MF/W Battery giving additional proof that the seafloor spreads at this site at a rate of about 2.5 cm (about 1 in) per year (see plate tectonics,).[29] In a series of dives conducted between 1979–1980 into the Galápagos rift, off the coast of Ecuador, French,Italian, Mexican, and U.S. scientists found vents, nearly 9 m (nearly 30 ft) high and about 3.7 m (about 12 ft) across, Sony VAIO VGN-NW21ZF Battery discharging a mixture of hot water (up to 300°C/570°F) and dissolved metals in dark, smoke-like plumes (see hydrothermal vent,). These hot springs play an important role in the formation of deposits that are enriched in copper, nickel, cadmium,chromium, and uranium. Deep-sea fish are fish that live in darkness below the surface waters lit by the sun, Sony VAIO VGN-NW31EF/W Battery that is below the photic zone of the ocean. The lanternfish is, by far, the most common deep-sea fish. Other deep sea fish include the flashlight fish,cookiecutter shark, bristlemouths, anglerfish, and viperfish. Only about 2% of known marine species inhabit the pelagic environment. Sony VAIO VGN-NW31JF Battery This means that they live in the water column as opposed to the benthic organisms that live in or on the sea floor.[1] Deep-sea organisms generally inhabit bathypelagic (1000m-4000m deep) and abyssopelagic (4000m-6000m deep) zones. However, characteristics of deep-sea organisms, such asbioluminescence can be seen in the mesopelagic (200m-1000m deep) zone as well. Sony VAIO VGN-NW320F/B Battery The mesopelagic zone is the disphotic zone, meaning light there is minimal but still measurable. The oxygen minimum layer exists somewhere between a depth of 700m and 1000m deep depending on the place in the ocean. This area is also where nutrients are most abundant. Sony VAIO VGN-NW320F/TC Battery

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