The abyssal zone is the abyssopelagic layer or pelagic zone that contains the very deep benthic communities near the bottom of oceans.

.The abyssal zone or abyssopelagic zone is a layer of the of the ocean. 'Abyss' derives from the word ἄβυσσος, meaning bottomless.

At depths of 3,000 to 6,000 metres (9,800 to 19,700 ft), this zone remains in perpetual darkness. It alone makes up over 83% of the ocean and covers 60% of the Earth. The abyssal zone has temperatures around 2 to 3 °C (36 to 37 °F) through the large majority of its mass. Due to there being no light, there are no plants producing oxygen, which primarily comes from ice that had melted long ago from the polar regions. The water along the seafloor of this zone is actually devoid of oxygen, resulting in a death trap for organisms unable to quickly return to the oxygen-enriched water above.

This region also contains a much higher concentration of nutrient salts, like nitrogen, phosphorus, and silica, due to the large amount of dead organic material that drifts down from the above ocean zones and decomposes.It is the deeper part of the midnight zone which starts in the waters above.The area below the abyssal zone is the sparsely inhabited. The zone above is the. Layers of the pelagic zoneThe deep trenches or fissures that plunge down thousands of meters below the ocean floor (for example, the midoceanic trenches such as the in the ) are almost unexplored. Previously, only the, the and the have been able to descend to these depths. However, as of March 25, 2012 one vehicle, the was able to penetrate to a depth of 10,898.4 meters (35,756 ft).Ecosystem Without plants, a cornerstone of any, a unique ecosystem forms.

Organisms that live in this zone cannot rely on plants or herbivores to be the bedrock of the ecosystem, instead the species that call the abyssal zone home resort to the only remaining way of acquiring energy. They must feed on each other or the dead organic material, that falls into the abyssal zone from the levels above it.

It is only because of this fallen material that life can exist at this level, to begin with. It replaces plants as the bedrock of the ecosystem while invertebrate decomposers take the place of herbivores as the primary consumer. The biomass of the abyssal zone actually increases when closer to the seafloor as most of the decomposing material and live there. Since most of the resources or nutrients are present near the seafloor, that area can hold more biomass because it is able to support a more complex than the upper areas of the abyssal zone.The sea floor of the abyssal zone consists of or is layered by different materials depending on the depth of the sea floor. If the seafloor is around 4000m below sea level, the seafloor usually consists of calcareous shells of foraminiferan. At depths greater than 4000m below sea level, the seafloor lacks these shells, as they dissolve once they reach a depth greater than 4000m. This leaves behind a seafloor consisting mostly of brown clay and the remaining silica from dead zooplankton and phytoplankton.

In some areas of this zone, organisms are able to sustain themselves off of. Some bacterial species use the vents to create and use chemical energy in order to produce their own food. For example, many of these organisms convert hydrogen sulfide to sulfate in order to produce chemical energy. They then take that energy and synthesize the carbon-based compounds they use as food. These organisms are then preyed upon by other organisms, meaning that the bacteria can also take the place of plants as part of the bedrock for this ecosystem.Biological adaptations Organisms that live at this depth have had to evolve to overcome challenges provided by the abyssal zone.

Fish and invertebrates had to evolve to withstand the sheer cold and intense pressure found at this level. They also had to not only find ways to hunt and survive in constant darkness but to thrive in an ecosystem that has less oxygen and biomass, energy sources or prey items, than the upper zones.

In order to survive in a region with so few resources and low temperatures, many fishes and other organisms developed a much slower metabolism and require much less oxygen than those from the upper zones. Movement for many animals living here is also very slow, which allows them to conserve energy. Their reproduction rates are also very slow in order to decrease competition and conserve energy. The animals living here typically have flexible stomachs and mouths so that when scarce food items are found they can consume as much as possible.Other challenges faced by life in the abyssal zone are the pressure and darkness caused by the zone’s depth. Many organisms living in this zone have evolved to minimize internal air spaces, such as. This adaptation helps to protect them from the extreme pressure, which can reach around 75 MPa (11,000 psi).

The absence of light also spawned many different adaptations, such as having large eyes or the ability to produce their own light. Large eyes would allow the detection and use of any light available, no matter how small. Another eye adaptation is that many deep-sea organisms have evolved eyes that are extremely sensitive to blue light. This is because as sunlight shines into the ocean, the water absorbs red light, while blue light, with its short wavelength continues moving down to the waters depths. This means that in the deep ocean, if any light remains then it is most likely blue light so animals wanting to capitalize on that light would need specialized eyes tuned to use it. Many organisms use other specialized organs or methods for sensing their surroundings, some in conjunction with specialized eyes.

The ability to make their own light is called. Fishes and organisms living in the abyssal zone have developed this ability in order to not only produce light for vision, but also to lure in prey or a mate and conceal their silhouette. Scientists believe that over 90% of life in the abyssal zone use some form of bioluminescence. Many animals that are bioluminescent will produce blue light since it moves farther underwater than other colored lights, as explained earlier. Due to this lack of light, complex designs and bright colors are not needed. Most fish species have evolved to be transparent, red, or black in order to better blend in with the darkness and not waste energy on developing and maintaining bright or complex designs.

Animals The abyssal zone is surprisingly made up of many different types of organisms, including microorganisms, crustaceans, (bivalves, snails, and cephalopods), different classes of fishes, and a number of others that might not have even been discovered yet. Most of the fish species in this zone are characterized as or fishes. Demersal fishes are a term that refers to fishes whose habitat is very close to or on the seafloor, typically less than five meters. Most fish species fit into that classification because the seafloor contains most of the abyssal zone’s nutrients so the most complex food web or greatest biomass would be in this region of the zone.For benthic organisms in the abyssal zone, species would need to have evolved morphological traits that could keep them out of oxygen-depleted water above the sea floor or a way to extract oxygen from the water above, but also, allow the animal access to the sea floor and the nutrients located there. There are also animals that spend their time in the upper portion of the abyssal zone, and even sometimes spending time in the zone directly above, the bathyal zone. While there a number of different fish species representing many different groups and classes, like or ray-finned fish, there are no known members of the class, animals such as sharks, rays, and chimeras, that make the abyssal zone their primary or constant habitat.

Whether this is due to the limited recourses, energy availability, or other physiological constraints is unknown. Most Chondrichthyes species will only go as deep as the bathyal zone.: Some species of this fish are considered demersal while others swim and live in the upper portions of the abyssal zone. They lack a swim bladder, so that high pressure is not an issue. They use bioluminescence to lure in prey with a specialized lure on their head. Ceratioidei anglerfish have an odd mating process. The male fuses with the much larger female and fertilizes her eggs. Once fused, the male will parasitize off of her for the rest of its life.

Tripod fish ( ): Their habitat is along the ocean floor, usually around 4,720 m below sea level. Their pelvic fins and caudal fin have long bony rays protruding from them.

They will face the current while standing still on their long rays. Once they sense food nearby, they will use their large pectoral fins to hit the unsuspecting prey towards their mouth. Each member of this species has both male and female reproductive organs so that if a mate cannot be found, they can self fertilize.: The gulper eel habitat range typically goes form a depth of 500 to 3,000 meters below sea level. Not only does this animal have a giant mouth, but the mouth is loosely hinged with a pouch built into its lower jaw, making it the perfect mouth for swallowing fish much larger than itself. Like the anglerfish it also lacks a swim bladder.

The eel's eyes most likely evolved to detect small traces of light instead of full images.: This octopus usually lives at a depth between 3,000 to 4,000 meters, no other octopus lives at these depths. They use the fins on top of their head, they look like flapping ears, to hover over the sea floor looking for food. They will use their arms to help change directions or crawl along the sea floor. In order to combat the intense pressure of the abyssal zone, this octopus species lost their ink sac during evolution. They also use their strand-like structured suction cups to help detect predators, food, and other aspects of their environment. (Genus ): There are no known fish that lives at depths greater than this one. The depth of the cusk eel's habitat can be as great as 8,370 meters below sea level.

This animal's ventral fins are specialized forked barbel-like organs that act as sensory organs.: This resident of the abyssal zone is known to live at a depth ranging from 800 and 4,000 meters. It has extremely large eyes, but a small mouth.

It is thought to be a species, meaning it only reproduces once and then dies after. This is seen as a way for the organism to conserve energy and have a higher chance of having some healthy strong children. This reproductive strategy could be very useful in low energy environments such as the abyssal zone.Environmental concerns As with all of the rest of the natural world has negative effects. Due to the zone’s depth, increasing global temperatures do not affect it as quickly or drastically as the rest of the world, but the zone is still afflicted.

Along with climate change and ocean acidification, pollutants, such as plastics, are also present in this zone. Plastics are especially bad for the abyssal zone due to the fact that these organisms have evolved to eat or try to eat anything that moves or appears to be detritus, resulting in most organisms consuming plastics instead of nutrients. Both ocean acidification and pollution are decreasing the already small biomass that resides within the abyssal zone. Another problem caused by humans is. Even though no fishery can fish for organisms anywhere near the abyssal zone, they are still causing harm. The abyssal zone is dependent on the dead organisms from the upper zones sinking to the seafloor in order to sustain an ecosystem since their ecosystem lacks producers, due to the lack of sunlight. If fish and other animals are being removed from the ocean, the frequency and amount of dead material reaching the abyssal zone will also decrease.

A future problem for the abyssal zone could be deep sea mining operations. The talks and planning for this industry have not only already begun but is quickly growing. This could be disastrous for this extremely fragile ecosystem since the ecological dangers for mining for deep sea mineral are many. It could increase the amount of pollution in not only the abyssal zone, but in the ocean as a whole, and would physically destroy habitats and the seafloor. While this industry would only be able to occur far into the future, it is still a looming threat to the abyssal zone and the rest of the ocean's inhabitants.See also. From the original on 18 April 2009. Retrieved 2009-04-27.

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Deep-sea fish are that live in the darkness below the sunlit surface waters, that is below the or of the. The is, by far, the most common deep-sea fish.

Other fishes include the, and some species of.Only about 2% of known marine species inhabit the environment. This means that they live in the as opposed to the organisms that live in or on the sea floor. Deep-sea organisms generally inhabit (1000–4000m deep) and (4000–6000m deep) zones. However, characteristics of deep-sea organisms, such as can be seen in the (200–1000m deep) zone as well. 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.

The and zones are, meaning that no light penetrates this area of the ocean. These zones make up about 75% of the inhabitable ocean space.The epipelagic zone (0–200m) is the area where light penetrates the water and photosynthesis occurs. This is also known as the. Because this typically extends only a few hundred meters below the water, the deep sea, about 90% of the ocean volume, is in darkness.

The deep sea is also an extremely hostile environment, with temperatures that rarely exceed 3 °C (37.4 °F) and fall as low as −1.8 °C (28.76 °F) (with the exception of hydrothermal vent ecosystems that can exceed 350 °C, or 662 °F), low oxygen levels, and pressures between 20 and 1,000 (between 2 and 100 ). Scale diagram of the layers of the pelagic zoneIn the deep ocean, the waters extend far below the epipelagic zone, and support very different types of pelagic fishes adapted to living in these deeper zones.In deep water, is a continuous shower of mostly organic falling from the upper layers of the water column. Its origin lies in activities within the productive. Marine snow includes dead or dying, , fecal matter, sand, soot and other inorganic dust.

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The 'snowflakes' grow over time and may reach several centimetres in diameter, travelling for weeks before reaching the ocean floor. However, most organic components of marine snow are consumed by, and other filter-feeding animals within the first 1,000 metres of their journey, that is, within the epipelagic zone. In this way marine snow may be considered the foundation of deep-sea and: As sunlight cannot reach them, deep-sea organisms rely heavily on marine snow as an energy source.Some deep-sea pelagic groups, such as the, and families are sometimes termed pseudoceanic because, rather than having an even distribution in open water, they occur in significantly higher abundances around structural oases, notably and over. The phenomenon is explained by the likewise abundance of prey species which are also attracted to the structures.Hydrostatic pressure increases by 1 atmosphere for every 10m in depth. Deep-sea organisms have the same pressure within their bodies as is exerted on them from the outside, so they are not crushed by the extreme pressure. Their high internal pressure, however, results in the reduced fluidity of their membranes because molecules are squeezed together.

Fluidity in cell membranes increases efficiency of biological functions, most importantly the production of proteins, so organisms have adapted to this circumstance by increasing the proportion of unsaturated fatty acids in the lipids of the cell membranes. In addition to differences in internal pressure, these organisms have developed a different balance between their metabolic reactions from those organisms that live in the epipelagic zone.

David Wharton, author of Life at the Limits: Organisms in Extreme Environments, notes 'Biochemical reactions are accompanied by changes in volume. If a reaction results in an increase in volume, it will be inhibited by pressure, whereas, if it is associated with a decrease in volume, it will be enhanced'. This means that their metabolic processes must ultimately decrease the volume of the organism to some degree.

Humans seldom encounter alive, so they pose little danger (though scientists have accidentally cut themselves examining their teeth).Most fish that have evolved in this harsh environment are not capable of surviving in laboratory conditions, and attempts to keep them in captivity have led to their deaths. Deep-sea organisms contain gas-filled spaces (vacuoles). Gas is compressed under high pressure and expands under low pressure. Because of this, these organisms have been known to blow up if they come to the surface. Characteristics.

Cruise the epipelagic zone at night and the mesopelagic zone during the day.The fish of the deep-sea have evolved various adaptations to survive in this region. Since many of these fish live in regions where there is no natural, they cannot rely solely on their eyesight for locating prey and mates and avoiding predators; deep-sea fish have appropriately to the extreme sub-photic region in which they live. Many of these organisms are blind and rely on their other senses, such as sensitivities to changes in local pressure and smell, to catch their food and avoid being caught. Those that aren't blind have large and sensitive eyes that can use light.

These eyes can be as much as 100 times more sensitive to light than human eyes. Also, to avoid predation, many species are dark to blend in with their environment.Many deep-sea fish are, with extremely large eyes adapted to the dark. Bioluminescent organisms are capable of producing light biologically through the agitation of molecules of luciferin, which then produce light.

This process must be done in the presence of oxygen. These organisms are common in the mesopelagic region and below (200m and below).

More than 50% of deep-sea fish, as well as some species of shrimp and squid, are capable of bioluminescence. About 80% of these organisms have photophores – light producing glandular cells that contain luminous bacteria bordered by dark colourings. Some of these photophores contain lenses, much like those in the eyes of humans, which can intensify or lessen the emanation of light. The ability to produce light only requires 1% of the organism's energy and has many purposes: It is used to search for food and attract prey, like the anglerfish; claim territory through patrol; communicate and find a mate, and distract or temporarily blind predators to escape. Also, in the mesopelagic where some light still penetrates, some organisms camouflage themselves from predators below them by illuminating their bellies to match the colour and intensity of light from above so that no shadow is cast. This tactic is known as counter-illumination.The lifecycle of deep-sea fish can be exclusively deep water although some species are born in shallower water and sink upon maturation. Regardless of the depth where eggs and larvae reside, they are typically pelagic.

This planktonic — drifting — lifestyle requires neutral buoyancy. In order to maintain this, the eggs and larvae often contain oil droplets in their plasma. When these organisms are in their fully matured state they need other adaptations to maintain their positions in the water column.

In general, water's density causes upthrust — the aspect of buoyancy that makes organisms float. To counteract this, the density of an organism must be greater than that of the surrounding water. Most animal tissues are denser than water, so they must find an equilibrium to make them float. Many organisms develop swim bladders (gas cavities) to stay afloat, but because of the high pressure of their environment, deep-sea fishes usually do not have this organ. Instead they exhibit structures similar to hydrofoils in order to provide hydrodynamic lift. It has also been found that the deeper a fish lives, the more jelly-like its flesh and the more minimal its bone structure. They reduce their tissue density through high fat content, reduction of skeletal weight — accomplished through reductions of size, thickness and mineral content — and water accumulation makes them slower and less agile than surface fish.Due to the poor level of light reaching deep-sea environments, most fish need to rely on matter sinking from higher levels, or, in rare cases, for nutrients.

This makes the deep-sea much poorer in than shallower regions. Also, animals in the pelagic environment are sparse and food doesn't come along frequently. Because of this, organisms need adaptations that allow them to survive.

Some have long feelers to help them locate prey or attract mates in the pitch black of the deep ocean. The deep-sea angler fish in particular has a long fishing-rod-like adaptation protruding from its face, on the end of which is a bioluminescent piece of skin that wriggles like a worm to lure its prey. Some must consume other fish that are the same size or larger than them and they need adaptations to help digest them efficiently. Great sharp teeth, hinged jaws, disproportionately large mouths, and expandable bodies are a few of the characteristics that deep-sea fishes have for this purpose. The is one example of an organism that displays these characteristics.Fish in the different pelagic and deep water benthic zones are physically structured, and behave in ways, that differ markedly from each other. Groups of coexisting species within each zone all seem to operate in similar ways, such as the small mesopelagic plankton-feeders, the bathypelagic, and the deep water benthic.

'species, with spiny fins, are rare among deep sea fishes, which suggests that deep sea fish are ancient and so well adapted to their environment that invasions by more modern fishes have been unsuccessful. The few ray fins that do exist are mainly in the and, which are also ancient forms. Most deep sea pelagic fishes belong to their own orders, suggesting a long evolution in deep sea environments. In contrast, deep water benthic species, are in orders that include many related shallow water fishes.

Species by pelagic zoneMany species move daily between zones in vertical migrations.In this table they are listed in the middle or deeper zone where they are regularly found.ZoneSpecies and species groups include.Epipelagic., and.,.,.,.Mesopelagic,BathypelagicPrincipally. The has large, forward-pointing telescoping eyes with large lenses.Below the epipelagic zone, conditions change rapidly.

Between 200 metres and about 1000 metres, light continues to fade until there is almost none. Temperatures fall through a to temperatures between 3.9 °C (39 °F) and 7.8 °C (46 °F). This is the twilight or zone. Pressure continues to increase, at the rate of one atmosphere every 10 metres, while nutrient concentrations fall, along with dissolved oxygen and the rate at which the water circulates.'

Sonar operators, using the newly developed sonar technology during World War II, were puzzled by what appeared to be a false sea floor 300–500 metres deep at day, and less deep at night. This turned out to be due to millions of marine organisms, most particularly small mesopelagic fish, with swimbladders that reflected the sonar. These organisms migrate up into shallower water at dusk to feed on plankton. The layer is deeper when the moon is out, and can become shallower when clouds pass over the moon. This phenomenon has come to be known as the.Most mesopelagic fish make daily, moving at night into the epipelagic zone, often following similar migrations of zooplankton, and returning to the depths for safety during the day.

These vertical migrations often occur over large vertical distances, and are undertaken with the assistance of a. The swimbladder is inflated when the fish wants to move up, and, given the high pressures in the messoplegic zone, this requires significant energy. As the fish ascends, the pressure in the swimbladder must adjust to prevent it from bursting. When the fish wants to return to the depths, the swimbladder is deflated. Some mesopelagic fishes make daily migrations through the, where the temperature changes between 50 °F (10 °C) and 69 °F (20 °C), thus displaying considerable tolerances for temperature change.These fish have muscular bodies, ossified bones, scales, well developed gills and central nervous systems, and large hearts and kidneys. Mesopelagic have small mouths with fine, while the have larger mouths and coarser gill rakers.

The vertically migratory fish have.Mesopelagic fish are adapted for an active life under low light conditions. Most of them are visual predators with large eyes.

Some of the deeper water fish have tubular eyes with big lenses and only that look upwards. These give binocular vision and great sensitivity to small light signals.

This adaptation gives improved terminal vision at the expense of lateral vision, and allows the predator to pick out, and smaller fish that are silhouetted against the gloom above them.Mesopelagic fish usually lack defensive spines, and use colour to themselves from other fish. Are dark, black or red.

Since the longer, red, wavelengths of light do not reach the deep sea, red effectively functions the same as black. Migratory forms use silvery colours. On their bellies, they often display producing low grade light. For a predator from below, looking upwards, this camouflages the silhouette of the fish. However, some of these predators have yellow lenses that filter the (red deficient) ambient light, leaving the bioluminescence visible.The, a species of, is the only vertebrate known to employ a mirror, as opposed to a lens, to focus an image in its eyes.Sampling via deep indicates that account for as much as 65% of all deep sea fish. Indeed, lanternfish are among the most widely distributed, populous, and diverse of all, playing an important role as prey for larger organisms. The estimated global biomass of lanternfish is 550 - 660 million, several times the entire world fisheries catch.

Lanternfish also account for much of the biomass responsible for the of the world's oceans. Reflects off the millions of lanternfish, giving the appearance of a false bottom.are an epipelagic/mesopelagic species that eats other fish. Satellite tagging has shown that bigeye tuna often spend prolonged periods cruising deep below the surface during the daytime, sometimes making dives as deep as 500 metres. These movements are thought to be in response to the vertical migrations of prey organisms in the. The widespread has the largest teeth of any fish, proportionate to body size.

Despite their ferocious appearance, bathypelagic fish are usually weakly muscled and too small to represent any threat to humans.Below the mesopelagic zone it is pitch dark. This is the midnight (or ), extending from 1000 metres to the bottom deep water. If the water is exceptionally deep, the pelagic zone below 4000 metres is sometimes called the lower midnight (or ).Conditions are somewhat uniform throughout these zones; the darkness is complete, the pressure is crushing, and temperatures, nutrients and dissolved oxygen levels are all low.Bathypelagic fish have special to cope with these conditions – they have slow and unspecialized diets, being willing to eat anything that comes along. They prefer to sit and wait for food rather than waste energy searching for it. The behaviour of bathypelagic fish can be contrasted with the behaviour of mesopelagic fish. Mesopelagic fish are often highly mobile, whereas bathypelagic fish are almost all lie-in-wait predators, normally expending little energy in movement.The dominant bathypelagic fishes are small and;, and are also common.

These fishes are small, many about 10 centimetres long, and not many longer than 25 cm. They spend most of their time waiting patiently in the water column for prey to appear or to be lured by their phosphors. What little energy is available in the bathypelagic zone filters from above in the form of detritus, faecal material, and the occasional invertebrate or mesopelagic fish. About 20 percent of the food that has its origins in the epipelagic zone falls down to the mesopelagic zone, but only about 5 percent filters down to the bathypelagic zone.Bathypelagic fish are sedentary, adapted to outputting minimum energy in a habitat with very little food or available energy, not even sunlight, only bioluminescence.

Their bodies are with weak, watery muscles and structures. Since so much of the fish is water, they are not compressed by the great pressures at these depths.

They often have extensible, hinged with recurved teeth. They are slimy, without. The central nervous system is confined to the lateral line and olfactory systems, the eyes are small and may not function, and, kidneys and hearts, and are small or missing.These are the same features found in fish, which suggests that during their evolution, bathypelagic fish have acquired these features through.

As with larvae, these features allow the fish to remain suspended in the water with little expenditure of energy.Despite their ferocious appearance, these beasts of the deep are mostly miniature fish with weak muscles, and are too small to represent any threat to humans.The swimbladders of deep sea fish are either absent or scarcely operational, and bathypelagic fish do not normally undertake vertical migrations. Filling bladders at such great pressures incurs huge energy costs. Some deep sea fishes have swimbladders which function while they are young and inhabit the upper epipelagic zone, but they wither or fill with fat when the fish move down to their adult habitat.The most important sensory systems are usually the, which responds to sound, and the, which responds to changes in water pressure. The system can also be important for males who find females by smell.Bathypelagic fish are black, or sometimes red, with few. When photophores are used, it is usually to entice prey or attract a mate. Because food is so scarce, bathypelagic predators are not selective in their feeding habits, but grab whatever comes close enough.

They accomplish this by having a large mouth with sharp teeth for grabbing large prey and overlapping which prevent small prey that have been swallowed from escaping.It is not easy finding a mate in this zone. Some species depend on. Others are, which doubles their chances of producing both eggs and sperm when an encounter occurs. The female anglerfish releases to attract tiny males. When a male finds her, he bites on to her and never lets go. When a male of the anglerfish species bites into the skin of a female, he releases an that digests the skin of his mouth and her body, fusing the pair to the point where the two circulatory systems join up.

The male then atrophies into nothing more than a pair of. This extreme ensures that, when the female is ready to spawn, she has a mate immediately available.Many forms other than fish live in the bathypelagic zone, such as squid, large whales, octopuses, sponges, sea stars, and, but this zone is difficult for fish to live in. Lantern fishSampling via deep indicates that account for as much as 65% of all deep-sea fish. Indeed, lanternfish are among the most widely distributed, populous, and diverse of all, playing an important role as prey for larger organisms. With an estimated global biomass of 550 - 660 million, several times the entire world fisheries catch, lanternfish also account for much of the biomass responsible for the of the world's oceans.

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Gordon J. (2001) In: John H. Steele, Steve A.

Thorpe, Karl K. Turekian (Eds) Elements of Physical Oceanography, pages 227–233, Academic Press. Hoar WS, Randall DJ and Farrell AP (Eds) (1997), Academic Press. Shotton, Ross (1995) In: Review of the state of world marine fishery resources, FAO Fisheries technical paper 457, FAO, Rome. Tandstad M, Shotton R, Sanders J and Carocci F (2011) In: Review of the state of world marine fishery resources, pages 265–278, FAO Fisheries technical paper 569, FAO, Rome.External links Media related to at Wikimedia Commons.

Articles, facts and images of deep sea animals.