A hydrothermal vent in the deep sea

The deep sea, or deep layer^[1] is the lowest layer in the ocean, existing below the thermocline. Little or no light penetrates this area of the ocean, and most of its organisms rely on falling organic matter produced in the photic zone for subsistence. For this reason scientists assumed 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. IMAX theatre at the Melbourne Museum complex, Australia BFI London IMAX by night IMAX (short for Image Maximum) is a film format created by Canadas IMAX Corporation that has the capacity to display images of far greater size and resolution than conventional film display systems. ... This article or section does not cite its references or sources. ... Image File history File links Download high resolution version (1220x1804, 532 KB) en: Black smoker at a mid-ocean ridge hydrothermal vent de: Black Smoker im Atlantischen Ozean Taken from http://www. ... Image File history File links Download high resolution version (1220x1804, 532 KB) en: Black smoker at a mid-ocean ridge hydrothermal vent de: Black Smoker im Atlantischen Ozean Taken from http://www. ... A hydrothermal vent A hydrothermal vent is a fissure in a planets surface from which geothermally heated water issues. ... Animated map exhibiting the worlds oceanic waters. ... The thermocline is a layer within a body of water where the temperature changes rapidly with depth. ... For other uses, see Light (disambiguation). ... The photic zone is the depth of the water, whether in a lake or an ocean, that is exposed to sufficient sunlight for photosynthesis to occur. ...

From the time of Pliny until the late nineteenth century...humans believed there was no life in the deep. It took a historic expedition in the ship Challenger between 1872 and 1876 to prove Pliny wrong; 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. The reverse is in fact true....(Below 200 meters) lies the largest habitat on earth. ^[2]

In 1960 the Bathyscaphe Trieste descended to the bottom of the Marianas Trench near Guam, at 35,798 feet the deepest spot on earth. If Mount Everest were submerged there its peak would be more than a mile beneath the surface. At this great depth a small flounder-like fish was seen moving away from the bathyscaphe's spotlight. The Japanese research submersible Kaiko was the only vessel capable of reaching this depth, and it was lost in 2003. The bathyscaphe Trieste Trieste was a Swiss-designed deep-diving research bathyscaphe (deep boat) with a crew of two people, which reached a record-breaking depth of about 10,900 m (about 35,760 ft), in the deepest part of any ocean on earth, the Challenger Deep in the Mariana... The Mariana Trench is the deepest known submarine trench, and the deepest location in the Earth itself. ... Kaiko was a remote control Japanese deep-sea submarine that sampled bacteria from the ocean floor of the Challenger Deep in the Mariana Trench, the deepest location in the world. ...

We know much less about the abyssal sea than about the moon. ^[3] Until the late 70s the accepted wisdom was that there could be no life without oxygen. This theory was overturned by the discovery of thriving colonies of shrimp and other organisms around hydrothermal vents in the deep ocean. These organisms thrive in completely lightless and anaerobic environments, in highly saline water that may reach 300 degrees F, drawing their sustenance from hydrogen sulfide, which is highly toxic to all terrestrial life. The revolutionary discovery that life can exist without oxygen or light significantly increases the chance of there being life elsewhere in the universe. Scientists now speculate that Europa, one of Jupiter's moons, may have conditions that could support life beneath its surface. Hydrothermal vents are fissures in a planets surface from which geothermally heated water issues. ... Europa is the name of : Europe, the continent, in most European languages (most Germanic languages, Latin and some Romance languages, and some Slavic Languages) Europa (mythology), a beautiful Phoenician princess in Greek mythology Europa (moon), the smallest of the Galilean moons of planet Jupiter Europa, a small island in the...

Biology

Regions below the epipelagic are divided into further zones, beginning with the mesopelagic which spans from 200 to 1000m 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. 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. Scale diagram of the layers of the pelagic zone. ... The pelagic zone is the part of the open sea or ocean comprising the water column, i. ... For considerations of sea level change, in particular rise associated with possible global warming, see sea level rise. ... Global oceanic and terrestrial photoautotroph abundance, from September 1997 to August 2000. ... The aphotic zone is the depth of the ocean that is not exposed to sunlight. ... The layers of the pelagic zone. ... Layers of the pelagic zone The abyssal zone is the pelagic zone that contains the very deep benthic communities near the bottom of oceans. ... The Hadal Zone is the deepest part of the Earth. ... In the deep ocean, marine snow is a continuous shower of mostly organic detritus falling from the upper layers of the water column. ...

Instead of relying on gas for their buoyancy, many species have jelly-like flesh consisting mostly of glycosaminoglycans, which has very low density[1]. 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 product ammonium chloride, which is lighter than sea water[2][3]. For other uses, see Squid (disambiguation). ...

Adaptations of midwater fish

The midwater fish have special adaptations to cope with these conditions - they are small, usually being under 25cm; they have slow metabolisms and unspecialized diets, preferring to sit and wait for food rather than waste energy searching for it. They have elongated bodies with weak, watery muscles and skeletal structures. They often have extendable, hinged jaws with recurved teeth. Because of the sparse distribution and lack of light, finding a partner with which to breed is difficult, and many organisms are hermaphroditic. For other uses, see Fish (disambiguation). ... For other uses, see Adaptation (disambiguation). ... Structure of the coenzyme adenosine triphosphate, a central intermediate in energy metabolism. ... For other uses of Muscle, see Muscle (disambiguation). ... For other uses, see Skeleton (disambiguation). ... Human jaw front view Human jaw left view Human jaw top view The jaw is either of the two opposable structures forming, or near the entrance to, the mouth. ... Types of teeth Molars are used for grinding up foods Carnassials are used for slicing food. ... For other uses, see Hermaphrodite (disambiguation). ...

Flashlight fish with bright photophore and eyeshine

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. Prey fish however also have adaptations to cope with predation. 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. 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. Flashlight fish have this plus photophores, which combination they use to detect eyeshine in other fish (see Tapetum lucidum). For other uses, see Eye (disambiguation). ... Rod cells, or rods, are photoreceptor cells in the retina of the eye that can function in less intense light than can the other type of photoreceptor, cone cells. ... For other uses, see Silhouette (disambiguation). ... Predator and Prey redirect here. ... This article is about protective camouflage used to disguise people, animals, or military targets. ... Bioluminescence is the production and emission of light by a living organism as the result of a chemical reaction during which chemical energy is converted to light energy. ... A photophore is a light-emitting organ which appears as luminous spots on various marine fishes. ... Night-vision is seeing in the dark. ... Retroreflectors are clearly visible in a pair of bicycle shoes. ... Human eye cross-sectional view. ... Genera Anomalops Phthanophaneron Kryptophanaron Parmops Photoblepharon Phthanophaneron Protoblepharon The term flashlight fish can either refer to: a family of fish, the Anomalopidae, also known as the lanterneye fish any one of a number of individual species, most but not all within that family, most commonly to the flashlight fish Photoblepharon... A photophore is a light-emitting organ which appears as luminous spots on various marine fishes. ... Tapetum lucidum in a calf eye, with the retina hanging down. ... Tapetum lucidum in a calf eye, with the retina hanging down. ...

Exploration

Main article: Deep-sea exploration

The deep sea is an environment totally inhospitable to humankind, and it should come as no surprise that it represents one of the least explored areas on Earth. 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. Because of the difficulty and cost of exploring this zone, current knowledge remains limited. Deep-sea exploration is the investigation of physical, chemical, and biological conditions on the sea bed, for scientific or commercial purposes. ... Variety of ROVs: Work Class, General, Mini Remotely operated underwater vehicles (ROVs) is the common accepted name for tethered underwater robots in the offshore industry. ...

References

USN redirects here. ...

External links