The decreased pressure makes the gases expand and small bubbles of nitrogen form in the blood stream as well as tissues. The result of this can be bone damage, extreme pain, physical debilitation, and even death . This can be seen in the case of the Frilled Shark that was found in shallow waters near Japan. Sony VAIO VPCF22M1E battery
They usually live at a depth of 1,500m, so when this specimen was transferred to a marine park it died within a few hours . For this reason little is known about them, as there are limitations to the amount of fruitful research that can be carried out on a dead specimen and deep-sea exploratory equipment is very expensive. Sony VAIO VPCF11M1E/H battery
As such, many species are known only to scientists and have therefore retained their scientific name.
The fish of the deep-sea are among the strangest and most elusive creatures on Earth. In this deep unknown lie many unusual creatures that have yet to be studied. Sony VAIO VPCF13M0E/B battery
Since many of these fish live in regions where there is no natural illumination, they cannot rely solely on their eyesight for locating prey and mates and avoiding predators; deep-sea fish have evolvedappropriately to the extreme sub-photic region in which they live. Many of these organisms are blind and rely on their other senses, Sony VAIO VPCYB2M1E battery
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 utilize bioluminescent light (discussed below). These eyes can be as much as 100 times more sensitive to light than human eyes. Sony VAIO VPCYB3V1E battery
Also, to avoid predation, many species are dark to blend in with their environment .
Many deep-sea fish are bioluminescent, 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 photons of light. Sony VAIO VPCY11M1E battery
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 colorings. Sony VAIO VPCS12L9E/B battery
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; Sony VAIO VPCF11S1E/B battery
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 color and intensity of light from above so that no shadow is cast. This tactic is known as counter illumination . Sony VAIO VPCYB3V1E/R Battery
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. Sony VAIO VPCF23P1E Battery
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. Sony VAIO VPCF23N1E Battery
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. Sony VAIO VPCY21S1E/L Battery
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, Sony VAIO VPCY21S1E/G battery
thickness, and mineral content – and water accumulation  makes them slower and less agile than surface fish.
Due to the poor level of photosynthetic light reaching deep-sea environments, most fish need to rely on organic matter sinking from higher levels, or, in rare cases, hydrothermal vents for nutrients. Sony VAIO VPCF24M1E battery
This makes the deep-sea much poorer inproductivity 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. Sony VGP-BPL8 Battery
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. Sony VGP-BPS8 Battery
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 gulper eel is one example of an organism that displays these characteristics.
Sampling via deep trawling indicates that lanternfish account for as much as 65% of all deep-sea fish biomass. Sony VGP-BPS8A Battery
Indeed, lanternfish are among the most widely distributed, populous, and diverse of all vertebrates, playing an important ecologicalrole as prey for larger organisms. With an estimated global biomass of 550 - 660 million metric tonnes, several times the entire world fisheries catch, Sony VGP-BPS9 Battery
lanternfish also account for much of the biomass responsible for the deep scattering layer of the world's oceans. In the Southern Ocean, Myctophids provide an alternative food resource to krill for predators such assquid and the King Penguin. Although plentiful and prolific, currently only a few commercial lanternfish fisheries exist: Sony VGP-BPS9/B Battery
These include limited operations off South Africa, in the sub-Antarctic, and in the Gulf of Oman.
A 2006 study by Canadian scientists has found five species of deep-sea fish – blue hake, spiny eel –Sony VGP-BPS9/S Battery
to be on the verge of extinction due to the shift ofcommercial fishing from continental shelves to the slopes of the continental shelves, down to depths of 1600 meters. The slow reproduction of these fish – they reach sexual maturity at about the same age as human beings – is one of the main reasons that they cannot recover from the excessive fishing. Sony VGP-BPS10 Battery
Deep-sea exploration is the investigation of physical, chemical, and biological conditions on the sea bed, for scientific or commercial purposes. Deep-seaexploration 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.Sony VGP-BPL10 Battery
The ocean depths still remain as a largely unexplored part of the planet, and form a relatively undiscovered domain.
In general, modern scientific Deep-sea exploration can be said to have begun when French scientist Pierre Simon de Laplace investigated the average depth of theAtlantic ocean by observing tidal motions registered on Brazilian and African coasts. Sony VGP-BPL11 Battery
He calculated the depth to be 3,962 m (13,000 ft), a value later proven quite accurate by soundings measurement. Later on, with increasing demand for submarine cables installment, accurate soundings was required and the first investigations of the sea bottom were undertaken. Sony VGP-BPS11 Battery
First deep-sea life forms were discovered in 1864 when Norwegian researchers obtained a sample of a stalkedcrinoid at a depth of 3,109 m (10,200 ft). 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. Sony VGP-BPL12 Battery
The first instrument used for deep-sea investigation was the sounding weight, used by British explorer Sir James Clark Ross. With this instrument, he reached a depth of 3,700 m (12,140 ft) in 1840. The Challenger expedition used similar instruments called Baillie sounding machines to extract samples from the sea bed. Sony VGP-BPS12 Battery
In 1960, Jacques Piccard and US Navy Lieutenant Donald Walsh descended in the bathyscaphe Trieste into the Mariana Trench, the deepest part of the world's oceans, to make the deepest dive in history: 10,915 meters (35,810 ft).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 VGP-BPS13 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 VGP-BPS13/B 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. Cornelius Drebbel, a Dutch architect, is generally given credit for construction of the first submarine. Sony VGP-BPS13/S 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 VGP-BPS13A/S Battery
It is believed that King James I may have enjoyed a short ride in the craft.
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. Sony VGP-BPS13B/S Battery
French author Jules Verne, 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 VGP-BPS13S 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. Sony VGP-BPS13AS 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 VGP-BPS13A/B 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.
Deep-sea exploration advanced considerably in the 1900s thanks to a series of technological inventions, Sony VGP-BPS13B/B 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 VGP-BPS14 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.
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 VGP-BPl15 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 extreme conditions in the deep sea require elaborate methods and technologies, which has been the main reason why its exploration has a comparatively short history. Sony VGP-BPs15 Battery
In the following, important key stones of deep sea exploration are listed.
1521: Ferdinand Magellan dropped a 700 m (2300 ft) long rope from his ship, which did not reach the ground and concluded that the sea was of infinite depth. Sony VGP-BPs18 Battery
1818: The British researcher Sir John Ross was the first to find that the deep sea is inhabited by life when catching jellyfish and worms in about 2000 m (6550 ft) depth with a special device.
1843: Nevertheless, Edward Forbes claimed that diversity of life in the deep sea is little and decreases with increasing depth. Sony VGP-BPS21A/B Battery
He stated that there could be no life in waters deeper than 550 m (1800 ft), the so-called Abyssus Theory.
1850: Near the Lofoten, Michael Sars found a rich deep sea fauna in a depth of 800 m (2600 ft) thereby refuting the Abyssus Theory. Sony VGP-BPS21/S Battery
1872–1876: The first systematic deep sea exploration was conducted by the Challenger Expedition on board the ship HMS Challenger led by Charles Wyville Thomson. This expedition revealed that the deep sea harbours a diverse, specialized biota.
1890–1898: First Austrian-Hungarian deep sea expedition on board the ship SMS Pola led by Franz Steindachner in the eastern Mediterranean and the Red Sea. Sony VGP-BPS21B Battery
1898–1899: First German deep sea expedition on board the ship Valdivia led by Carl Chun; found many new species from depths greater than 4000 m (13000 ft) in the southern Atlantic Ocean.
1930: William Beebe and Otis Barton are the first humans to reach the Deep Sea when diving in the so-called Bathysphere, made from steel. Sony VGP-BPS21 Battery
They reach a depth of 435 m (1430 ft), where they observed jellyfish and shrimp.
1934: The Bathysphere reached a depth of 923 m (3028 ft).
1948: Otis Barton set out for a new record reaching a depth of 1370 m (4495 ft). Sony Vaio PCG-5G2L Battery
1960: Jacques Piccard and Don Walsh reached the bottom of the Challenger Deep in the Mariana Trench, descending to a depth of 10,740 m (35236 ft) in their deep sea vessel Trieste, where they observed fish and other deep sea organisms.
2012: The vessel Deepsea Challenger, piloted by James Cameron, completes the second manned voyage and first solo mission to the bottom of the Challenger Deep. Sony Vaio PCG-5G3L Battery
The sounding weight, one of the first instruments used for the sea bottom investigation, 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. Sony Vaio PCG-5J1L Battery
The sounding weights used on the HMS Challenger were slightly advanced called "Baillie sounding machine". The British researchers used wire-line soundings to investigate sea depths and collected hundreds of biological samples from all the oceans except the Arctic. Sony Vaio PCG-5J2L Battery
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.
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. Sony Vaio PCG-5K2L Battery