What is at the bottom of the Mariana. Mariana Trench and its mysterious inhabitants. Unknown
Now anyone can watch the fantastic underwater world captured on video. Mariana Trench, the deepest place on our planet, or even enjoy a live video broadcast from an 11-kilometer depth. But until relatively recently, the Mariana Trench was considered the most unexplored point on the map of the Earth.
Sensational discovery by the Challenger team
More from school curriculum we know that the highest point earth's surface is the peak of Mount Everest (8848 m), but the lowest is hidden under the waters of the Pacific Ocean and is located at the bottom of the Mariana Trench (10994 m). We know quite a lot about Everest; climbers have conquered its peak more than once; there are enough photographs of this mountain taken both from the ground and from space. If Everest is all in plain sight and does not pose any mystery to scientists, then the depths of the Mariana Trench keep many secrets, because getting to its bottom requires this moment Only three daredevils succeeded.
The Mariana Trench is located in the western part of the Pacific Ocean; it got its name from the Mariana Islands, which are located next to it. A place unique in depth seabed received the status of a US national monument; fishing and mining are prohibited here; in fact, it is a huge marine reserve. The shape of the depression is similar to a huge crescent, reaching 2550 km in length and 69 km in width. The bottom of the depression has a width of 1 to 5 km. The deepest point of the depression (10,994 m below sea level) was named “Challenger Deep” in honor of the British ship of the same name.
The honor of discovering the Mariana Trench belongs to the team of the British research vessel Challenger, which in 1872 carried out depth measurements at a number of points in the Pacific Ocean. When the ship found itself in the area of the Mariana Islands, during the next depth measurement a hitch arose: the kilometer-long rope all went overboard, but it was not possible to reach the bottom. At the captain’s direction, a couple more kilometer sections were added to the rope, but, to everyone’s surprise, they were not enough and had to be added again and again. Then it was possible to establish a depth of 8367 meters, which, as it became known later, was significantly different from the real one. However, even the underestimated value was quite enough to understand: the most deep place.
It is amazing that already in the 20th century, in 1951, it was the British who, using a deep-sea echo sounder, clarified the data of their compatriots; this time the maximum depth of the depression was more significant - 10,863 meters. Six years later, Soviet scientists began studying the Mariana Trench, arriving in this area of the Pacific Ocean on the research vessel Vityaz. Using special equipment, they recorded the maximum depth of the depression at 11,022 meters, and most importantly, they were able to establish the presence of life at a depth of about 7,000 meters. It is worth noting that in scientific world Then there was an opinion that due to the monstrous pressure and lack of light at such depths, there were no manifestations of life.
Dive into the world of silence and darkness
In 1960, people visited the bottom of the depression for the first time. How difficult and dangerous such a dive was can be judged by the colossal water pressure, which at the lowest point of the depression is 1072 times higher than the average atmospheric pressure. The dive to the bottom of the depression using the Trieste bathyscaphe was carried out by US Navy Lieutenant Don Walsh and researcher Jacques Picard. Bathyscaphe "Trieste" with walls 13 cm thick was created in the same name Italian city and was a rather massive structure.
They lowered the submersible to the bottom for five long hours; Despite such a long descent, the researchers spent only 20 minutes at the bottom at a depth of 10,911 meters; it took them about 3 hours to rise. Within minutes of being in the abyss, Walsh and Picard were able to make a very impressive discovery: they saw two 30-centimeter flat fish, similar to flounder, that swam past their porthole. Their presence at such a depth became a real scientific sensation!
In addition to the discovery of the presence of life at such a mind-boggling depth, Jacques Piccard was able to experimentally refute the then prevailing opinion that at depths of more than 6000 m there is no upward movement of water masses. In terms of ecology, this was a major discovery, because some nuclear powers were planning to bury radioactive waste in the Mariana Trench. It turns out that Picard prevented large-scale radioactive contamination of the Pacific Ocean!
After the dive of Walsh and Picard, for a long period only unmanned automatic bathyscaphes descended into the Mariana Trench, and there were only a few of them, because they were very expensive. For example, on May 31, 2009, the American deep-sea vehicle Nereus reached the bottom of the Mariana Trench. He not only spent on incredible depth underwater photography and video shooting, but also took soil samples. The instruments of the deep-sea vehicle recorded the depth it reached at 10,902 meters.
On March 26, 2012, a man again found himself at the bottom of the Mariana Trench; it was the famous director, creator of the legendary film “Titanic,” James Cameron.
He explained his decision to make such a dangerous journey to the “bottom of the Earth” as follows: “Almost everything on the earth’s land has been explored. In space, bosses prefer to send people circling around the Earth, and send machine guns to other planets. For the joys of discovering the unknown, there is only one field of activity left - the ocean. Only about 3% of its water volume has been studied, and what’s next is unknown.”
Cameron made a dive on the DeepSea Challenge bathyscaphe, it was not very comfortable, researcher long time was in a half-bent state, since the diameter of the interior of the device was only about 109 cm. The bathyscaphe, equipped with powerful cameras and unique equipment, allowed the popular director to film fantastic landscapes of the deepest place on the planet. Later together with The National Geographic James Cameron has created a spectacular documentary"Challenge the Abyss"
It is worth noting that while at the bottom deepest depression world, Cameron saw neither monsters, nor representatives of an underwater civilization, nor an alien base. However, he literally looked into the eyes of the Challenger Abyss. According to him, during his short journey he experienced sensations indescribable in words. The ocean floor seemed to him not only deserted, but somehow “lunar... lonely.” He experienced a real shock from the feeling of “complete isolation from all humanity.” True, problems with the equipment of the bathyscaphe may have interrupted the “hypnotic” effect of the abyss on the famous director in time, and he rose to the surface among the people.
Inhabitants of the Mariana Trench
Behind last years During the exploration of the Mariana Trench, many discoveries were made. For example, in bottom soil samples taken by Cameron, scientists found more than 20 thousand of a wide variety of microorganisms. Among the inhabitants of the depression there are also giant 10-centimeter amoebas, called xenophyophores. According to scientists, single-celled amoebas most likely reached such incredible sizes due to the rather hostile environment at a depth of 10.6 km in which they are forced to live. High pressure, cold water and the absence of light for some reason clearly benefited them, contributing to their gigantism.
Mollusks were also discovered in the Mariana Trench. It is unclear how their shells withstand enormous water pressure, but they feel very comfortable at depth, and are located next to hydrothermal vents that emit hydrogen sulfide, which is lethal to ordinary mollusks. However, local mollusks, having demonstrated incredible abilities for chemistry, somehow adapted to process this destructive gas into protein, which allowed them to live where, at first
look, it’s impossible to live.
Many of the inhabitants of the Mariana Trench are quite unusual. For example, scientists discovered here a fish with a transparent head, in the center of which are its eyes. Thus, during the course of evolution, the eyes of the fish received reliable protection from possible injury. On enormous depth There are quite a few bizarre and sometimes even scary fish; here we managed to capture on video a fantastically beautiful jellyfish. Of course, we don’t yet know all the inhabitants of the Mariana Trench; in this regard, scientists still have many discoveries to make.
There are a lot of interesting things in this mysterious place and for geologists. Thus, in a depression at a depth of 414 meters, the Daikoku volcano was discovered, in the crater of which there is a lake of seething molten sulfur right under the water. As scientists say, the only analogue of such a lake known to them is only on Jupiter’s satellite, Io. Also in the Mariana Trench, scientists found the only underwater source of liquid carbon dioxide on earth, called “Champagne” in honor of the famous French
alcoholic drink. There are also so-called black smokers in the depression; these are hydrothermal springs operating at a depth of about 2 kilometers, thanks to which the water temperature in the Mariana Trench is maintained within fairly favorable limits - from 1 to 4 degrees Celsius.
At the end of 2011, scientists discovered very mysterious structures in the Mariana Trench; these are four stone “bridges” stretching from one end of the trench to the other for 69 kilometers. Scientists are still at a loss to explain how these “bridges” arose; they believe that they were formed at the junction of the Pacific and Philippine tectonic plates.
The study of the Mariana Trench continues. This year, from April to July, scientists from the American National Administration oceanic and atmospheric research. Their ship was equipped with a remotely controlled vehicle, which was used to film video underwater world the deepest place in the world's oceans. The video broadcast from the bottom of the depression could be seen not only by scientists, but also by Internet users.
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Even though the oceans are closer to us than distant planets solar system, humans have explored just five percent of the ocean floor, which remains one of our planet's greatest mysteries. The deepest part of the ocean - the Mariana Trench or Mariana Trench is one of the deepest famous places, about which we still don’t know very much. With water pressure that is a thousand times greater than at sea level, diving into this place is akin to suicide. But thanks modern technologies and to several brave souls who, risking their lives, went down there, we learned a lot of interesting things about this amazing place.
The Mariana Trench or Mariana Trench is located in the western Pacific Ocean east (about 200 km) of the 15 Mariana Islands near Guam. It is a crescent-shaped trench in earth's crust about 2550 km long and 69 km wide on average.
Mariana Trench coordinates: 11°22′ northern latitude and 142°35′ east longitude.
According to the latest research in 2011, the depth of the deepest point of the Mariana Trench is about 10,994 meters ± 40 meters. For comparison, the height of the high peak world - Everest is 8,848 meters. This means that if Everest were in the Mariana Trench, it would be covered by another 2.1 km of water.
Here are others Interesting Facts about what can be found along the way and at the very bottom of the Mariana Trench.
1. Very hot water
Going down to such depths, we expect it to be very cold. Temperatures here reach just above zero, varying from 1 to 4 degrees Celsius. However, at a depth of about 1.6 km from the surface of the Pacific Ocean there are hydrothermal vents called “black smokers”. They shoot water that heats up to 450 degrees Celsius.
This water is rich in minerals that help support life in the area. Despite the water temperature being hundreds of degrees above the boiling point, the water here does not boil due to the incredible water pressure, 155 times higher than on the surface.
2. Giant toxic amoebas
A few years ago, giant 10-centimeter amoebae called xenophyophores were discovered at the bottom of the Mariana Trench. These single-celled organisms likely became so large because of the environment they live in at a depth of 10.6 km. Cold temperature, high pressure and lack sunlight, most likely, contributed to the fact that these amoebas acquired enormous sizes.
In addition, xenophyophores have incredible abilities. They are resistant to many elements and chemical substances, including uranium, mercury and lead, which would kill other animals and people.
3. Shellfish
The intense water pressure in the Mariana Trench does not give any animal with a shell or bones a chance of survival. However, in 2012, shellfish were discovered in a trench near serpentine hydrothermal vents. Serpentine contains hydrogen and methane, which allows living organisms to form. How the mollusks preserved their shells under such pressure remains unknown.
In addition, hydrothermal vents emit another gas, hydrogen sulfide, which is lethal to shellfish. However, they learned to bind the sulfur compound into a safe protein, which allowed the population of these mollusks to survive.
4. Pure liquid carbon dioxide
The Champagne Mariana Trench hydrothermal vent, which lies outside the Okinawa Trench near Taiwan, is the only known underwater area where liquid carbon dioxide can be found. The spring, discovered in 2005, was named after the bubbles that turned out to be carbon dioxide.
Many believe these springs, called "white smokers" due to their lower temperatures, may be the source of life. It was in the depths of the oceans, with low temperatures and an abundance of chemicals and energy, that life could begin.
5. Slime
If we had the opportunity to swim to the very depths of the Mariana Trench, we would feel that it was covered with a layer of viscous mucus. Sand, in its familiar form, does not exist there. The bottom of the depression is mainly made up of crushed shells and remains of plankton that have sunk to the bottom over the years. Due to the incredible water pressure, almost everything there turns into fine grayish-yellow thick mud.
6. Liquid sulfur
The Daikoku volcano, which is located at a depth of about 414 meters on the way to the Mariana Trench, is the source of one of the most rare phenomena on our planet. There is a lake of pure molten sulfur here. The only place where liquid sulfur can be found is Jupiter's moon Io.
In this pit, called the "cauldron", the bubbling black emulsion boils at 187 degrees Celsius. Although scientists have not been able to explore this site in detail, it is possible that even more liquid sulfur is contained deeper. This could reveal the secret of the origin of life on Earth.
According to the Gaia hypothesis, our planet is one self-governing organism in which everything living and nonliving is connected to support its life. If this hypothesis is correct, then a number of signals can be observed in the natural cycles and systems of the Earth. So the sulfur compounds created by organisms in the ocean must be stable enough in the water to allow them to move into the air and return to land.
7. Bridges
At the end of 2011, four stone bridge, which extended from one end to the other for 69 km. They appear to have formed at the junction of the Pacific and Philippine tectonic plates.
One of the Dutton Ridge bridges, which was opened in the 1980s, turned out to be incredibly high, like a small mountain. In the most high point, the ridge reaches 2.5 km above the Challenger Deep. Like many aspects of the Mariana Trench, the purpose of these bridges remains unclear. However, the very fact that these formations were discovered in one of the most mysterious and unexplored places is surprising.
8. James Cameron's Dive into the Mariana Trench
Since the discovery of the deepest part of the Mariana Trench, the Challenger Deep, in 1875, only three people have visited it. The first were American Lieutenant Don Walsh and explorer Jacques Piccard, who dived on January 23, 1960 on the Challenger.
52 years later, another person dared to dive here - the famous film director James Cameron. So on March 26, 2012, Cameron went down to the bottom and took several photographs. During James Cameron's 2012 dive into the Challenger Deep on the DeepSea Challenge submersible, he attempted to observe everything that was happening in the area until mechanical problems forced him to the surface.
While he was at the deepest point of the world's oceans, he came to the shocking conclusion that he was completely alone. There were no scary things in the Mariana Trench sea monsters or some miracles. According to Cameron, the very bottom of the ocean was "lunar...empty...lonely" and he felt "complete isolation from all humanity."
9. Mariana Trench
10. The Mariana Trench in the ocean is the largest nature reserve
The Mariana Trench is a US national monument and the largest marine sanctuary in the world. Since it is a monument, there are a number of rules for those who want to visit this place. Within its borders, fishing and mining are strictly prohibited. However, swimming is allowed here, so you could be the next one to venture into the deepest place in the ocean.
The Mariana Trench, or Mariana Trench, is an oceanic depression in the western Pacific Ocean, which is the deepest geographical feature known on Earth.
Studies of the Mariana Trench were initiated by the expedition (December 1872 - May 1876) of the English ship HMS Challenger, which carried out the first systematic measurements of the depths of the Pacific Ocean. This military three-masted corvette with sail rigging was rebuilt as an oceanographic vessel for hydrological, geological, chemical, biological and meteorological work in 1872.
Also, a significant contribution to the study of the Mariana deep-sea trench was made by Soviet researchers. In 1958, an expedition on the Vityaz established the presence of life at depths of more than 7000 m, thereby refuting the prevailing idea at that time about the impossibility of life at depths of more than 6000-7000 m.
“Vityaz” in Kaliningrad on eternal parking
Half a century ago, on January 23, 1960, it happened significant event in the history of the conquest of the world's oceans.
Bathyscaphe Trieste, manned French explorer Jacques Piccard (1922–2008) and US Navy Lieutenant Don Walsh, reached the deepest point of the ocean floor - the Challenger Deep, located in the Mariana Trench and named after the English ship "Challenger", with which in 1951 the first data about it were obtained. The dive lasted 4 hours 48 minutes and ended at 10911 m relative to sea level. In this terrible depths, where a monstrous pressure of 108.6 MPa (which is more than 1,100 times greater than normal atmospheric pressure) flattens all living things, the researchers made a major oceanological discovery: they saw two 30-centimeter fish similar to flounder swim past the porthole. Before this, it was believed that no life existed at depths exceeding 6000 m.
Thus, an absolute record for diving depth was set, which cannot be surpassed even theoretically. Picard and Walsh were the only people to reach the bottom of the Challenger Deep. All subsequent dives to the deepest point of the world's oceans, for research purposes, were made by unmanned robotic bathyscaphes. But there were not so many of them, since “visiting” the Challenger Abyss is both labor-intensive and expensive.
One of the achievements of this immersion, which had a beneficial effect on the ecological future of the planet, was the refusal nuclear powers from the burial of radioactive waste at the bottom of the Mariana Trench. The fact is that Jacques Picard experimentally refuted the prevailing opinion at that time that at depths above 6000 m there is no upward movement of water masses.
In the 90s, three dives were made by the Japanese Kaiko device, controlled remotely from the “mother” ship via a fiber-optic cable. However, in 2003, while exploring another part of the ocean, the towing line broke off during a storm. steel rope, and the robot was lost.
The underwater catamaran Nereus became the third deep-sea vehicle to reach the bottom of the Mariana Trench.
On May 31, 2009, humanity again reached the deepest point of the Pacific, and indeed the entire world ocean - the American deep-sea vehicle Nereus sank into the Challenger failure at the bottom of the Mariana Trench. The device took soil samples and carried out underwater photo and video shooting on maximum depth, illuminated only by its LED spotlight.
In the hands of student Eleanor Bors - sea cucumber, living in the abyss itself and picked up by the Nereus apparatus.
During the current dive, Nereus' instruments recorded a depth of 10,902 meters. The indicator of “Kayko”, which first landed here in 1995, was 10,911 meters, and Picard and Walsh measured a value of 10,912 meters. On many Russian maps, the value of 11,022 meters obtained by the Soviet oceanographic vessel “Vityaz” during the 1957 expedition is still given. Of course, all this indicates the inaccuracy of the measurements, and not a real change in depth: no one carried out cross-calibration of the measuring equipment that gave the given values.
The Mariana Trench is formed by the boundaries of two tectonic plates: the colossal Pacific plate goes under the not so large Philippine plate. This is an extremely high zone seismic activity, part of the so-called Pacific volcanic ring of fire, stretching for 40 thousand km, an area with the most frequent eruptions and earthquakes in the world. The deepest point of the trench is the Challenger Deep, named after the English ship.
The depression stretches along the Mariana Islands for 1500 km; it has a V-shaped profile, steep (7-9°) slopes, a flat bottom 1-5 km wide, which is divided by rapids into several closed depressions. At the bottom, the water pressure reaches 108.6 MPa, which is more than 1100 times more than normal atmospheric pressure at the level of the World Ocean. The depression is located at the junction of two tectonic plates, in the zone of movement along faults, where the Pacific plate goes under the Philippine plate.
The inexplicable and incomprehensible have always attracted people, which is why scientists around the world want to answer the question: “What does the Mariana Trench hide in its depths?”
Can living organisms live at such great depths, and what should they look like, given the fact that huge masses are pressing on them? ocean waters, whose pressure exceeds 1100 atmospheres? The challenges associated with exploring and understanding the creatures that live at these unimaginable depths are numerous, but human ingenuity knows no bounds. For a long time Oceanologists considered the hypothesis that at depths of more than 6,000 m in impenetrable darkness, under monstrous pressure and at temperatures close to zero, life could exist as madness. However, the results of research by scientists in Pacific Ocean showed that in these depths, much below the 6000-meter mark, there are huge colonies of living organisms pogonophora (pogonophora; from the Greek pogon - beard and phoros - bearing), a type of marine invertebrate animals living in long chitinous, open on both sides ends of the tubes). IN Lately The veil of secrecy was lifted by manned and automatic underwater vehicles made of heavy-duty materials, equipped with video cameras. The result was the discovery of a rich animal community consisting of both familiar and less familiar marine groups.
Thus, at depths of 6000 - 11000 km, the following were discovered:
Barophilic bacteria (developing only at high pressure);
Of the protozoa - foraminifera (an order of protozoa of the subclass of rhizomes with a cytoplasmic body covered with a shell) and xenophyophores (barophilic bacteria from protozoa);
From multicellular - polychaete worms, isopods, amphipods, sea cucumbers, bivalves and gastropods.
At the depths there is no sunlight, no algae, constant salinity, low temperatures, an abundance of carbon dioxide, enormous hydrostatic pressure (increases by 1 atmosphere for every 10 meters). What do the inhabitants of the abyss eat?
The food sources of deep animals are bacteria, as well as the rain of “corpses” and organic detritus coming from above; deep animals are either blind, or with very developed eyes, often telescopic; many fish and cephalopods with photofluoride; in other forms the surface of the body or parts of it glow. Therefore, the appearance of these animals is as terrible and incredible as the conditions in which they live. Among them are frightening-looking worms 1.5 meters long, without a mouth or anus, mutant octopuses, extraordinary sea stars and some soft-bodied creatures two meters long, which have not yet been identified at all.
Despite the fact that scientists have made a huge step in researching the Mariana Trench, the questions have not decreased, and new mysteries have appeared that have yet to be solved. And the ocean abyss knows how to keep its secrets. Will people be able to reveal them in the near future?
—> Satellite view of the depression <—
The Mariana Trench (or Mariana Trench) is the deepest place on the earth's surface. It is located on the western edge of the Pacific Ocean, 200 kilometers east of the Mariana Archipelago.
It’s paradoxical, but humanity knows much more about the secrets of space or mountain peaks than about the depths of the ocean. And one of the most mysterious and unexplored places on our planet is the Mariana Trench. So what do we know about him?
Mariana Trench - the bottom of the world
In 1875, the crew of the British corvette Challenger discovered a place in the Pacific Ocean where there was no bottom. Kilometer after kilometer the line of the lot went overboard, but there was no bottom! And only at a depth of 8184 meters the descent of the rope stopped. This is how the deepest underwater crack on Earth was discovered. It was called the Mariana Trench, named after the nearby islands. Its shape (in the form of a crescent) and the location of the deepest section, called the “Challenger Deep,” were determined. It is located 340 km south of the island of Guam and has coordinates 11°22′ N. latitude, 142°35′ e. d. 
Since then this deep-sea depression has been called the “fourth pole”, “the womb of Gaia”, “the bottom of the world”. Oceanographers have long tried to find out its true depth. Studies over the years have given different values. The fact is that at such a colossal depth, the density of water increases as it approaches the bottom, therefore the properties of the sound from the echo sounder in it also change. Using barometers and thermometers at different levels along with echo sounders, in 2011 the depth in the Challenger Deep was determined to be 10994 ± 40 meters. This is the height of Mount Everest plus another two kilometers above.
The pressure at the bottom of the underwater chasm is almost 1100 atmospheres, or 108.6 MPa. Most deep-sea vehicles are designed for a maximum depth of 6-7 thousand meters. During the time that has passed since the discovery of the deepest canyon, it was possible to successfully reach its bottom only four times. 
In 1960, the deep-sea bathyscaphe Trieste, for the first time in the world, descended to the very bottom of the Mariana Trench in the Challenger Deep area with two passengers on board: US Navy Lieutenant Don Walsh and Swiss oceanographer Jacques Piccard.
Their observations led to an important conclusion about the presence of life at the bottom of the canyon. The discovery of an upward flow of water also had important environmental significance: based on it, nuclear powers refused to dump radioactive waste at the bottom of the Mariana Trench. 
In the 90s, the trench was explored by the Japanese unmanned probe "Kaiko", which brought samples of silt from the bottom in which bacteria, worms, shrimp were found, as well as pictures of a hitherto unknown world.
In 2009, the American robot Nereus conquered the abyss, picking up from the bottom samples of silt, minerals, samples of deep-sea fauna and photos of the inhabitants of unknown depths. 
In 2012, James Cameron, the author of Titanic, Terminator and Avatar, dived alone into the abyss. He spent 6 hours at the bottom, collecting samples of soil, minerals, fauna, as well as taking photographs and 3D video filming. Based on this material, the film “Challenge the Abyss” was created.
Amazing discoveries
In the trench, at a depth of about 4 kilometers, there is an active Daikoku volcano, spewing liquid sulfur that boils at 187 ° C in a small depression. The only lake of liquid sulfur was discovered only on Jupiter’s moon, Io. 
“Black smokers” swirl 2 kilometers from the surface - sources of geothermal water with hydrogen sulfide and other substances that, upon contact with cold water, turn into black sulfides. The movement of sulfide water resembles clouds of black smoke. The water temperature at the point of release reaches 450° C. The surrounding sea does not boil only because of the density of the water (150 times greater than at the surface). 
In the north of the canyon there are “white smokers” - geysers spewing liquid carbon dioxide at a temperature of 70-80 ° C. Scientists suggest that it is in such geothermal “cauldrons” that one should look for the origins of life on Earth. Hot springs “heat” the icy waters, supporting life in the abyss - the temperature at the bottom of the Mariana Trench is between 1-3° C. 
Life beyond life
It would seem that in an environment of complete darkness, silence, icy cold and unbearable pressure, life in the depression is simply unthinkable. But studies of the depression prove the opposite: there are living creatures almost 11 kilometers under water! 
The bottom of the hole is covered with a thick layer of slime from organic sediments that have been sinking from the upper layers of the ocean for hundreds of thousands of years. Mucus is an excellent breeding ground for barrophilic bacteria, which form the basis of nutrition for protozoa and multicellular organisms. The bacteria, in turn, become food for more complex organisms. 
The ecosystem of the underwater canyon is truly unique. Living beings have managed to adapt to an aggressive, destructive environment under normal conditions, with high pressure, lack of light, low amounts of oxygen and high concentrations of toxic substances. Life in such unbearable conditions gave many of the inhabitants of the abyss a frightening and unattractive appearance. 
Deep-sea fish have incredibly large mouths lined with sharp, long teeth. High pressure made their bodies small (from 2 to 30 cm). However, there are also large specimens, such as the xenophyophora amoeba, reaching 10 cm in diameter. The frilled shark and goblin shark, which live at a depth of 2000 meters, generally reach 5-6 meters in length. 
Representatives of different species of living organisms live at different depths. The deeper the inhabitants of the abyss, the better developed their organs of vision are, allowing them to catch the slightest reflection of light on the body of prey in complete darkness. Some individuals themselves are capable of producing directional light. Other creatures are completely devoid of organs of vision; they are replaced by organs of touch and radar. With increasing depth, underwater inhabitants increasingly lose their color; the bodies of many of them are almost transparent. 
On the slopes where the “black smokers” are located, mollusks live that have learned to neutralize sulfides and hydrogen sulfide that are lethal to them. And, which still remains a mystery to scientists, under conditions of enormous pressure at the bottom, they somehow miraculously manage to keep their mineral shell intact. Other inhabitants of the Mariana Trench show similar abilities. The study of fauna samples showed many times higher levels of radiation and toxic substances. 
Unfortunately, deep-sea creatures die due to changes in pressure when any attempt is made to bring them to the surface. Only thanks to modern deep-sea vehicles has it become possible to study the inhabitants of the depression in their natural environment. Representatives of fauna unknown to science have already been identified. 
Secrets and riddles of the “womb of Gaia”
The mysterious abyss, like any unknown phenomenon, is shrouded in a mass of secrets and mysteries. What does she hide in her depths? Japanese scientists claimed that while feeding goblin sharks, they saw a shark 25 meters long devouring goblins. A monster of this size could only be a megalodon shark, which became extinct almost 2 million years ago! This is confirmed by the findings of megalodon teeth in the vicinity of the Mariana Trench, whose age dates back to only 11 thousand years. It can be assumed that specimens of these monsters still exist in the depths of the hole. 
There are many stories about the corpses of giant monsters washed up on the shore. When descending into the abyss of the German bathyscaphe "Haifish", the dive stopped 7 km from the surface. To understand the reason, the passengers of the capsule turned on the lights and were horrified: their bathyscaphe, like a nut, was trying to chew some kind of prehistoric lizard! Only a pulse of electric current through the outer skin managed to scare away the monster.
Another time, when an American submersible was diving, the grinding of metal began to be heard from under the water. The descent was stopped. Upon inspection of the raised equipment, it turned out that the titanium alloy metal cable was half sawed (or chewed), and the beams of the underwater vehicle were bent. 
In 2012, the video camera of the Titan unmanned aerial vehicle from a depth of 10 kilometers transmitted a picture of metal objects, presumably a UFO. Soon the connection with the device was interrupted.
Unfortunately, there is no documentary evidence of these interesting facts; they are all based only on eyewitness accounts. Each story has its fans and skeptics, its arguments for and against. 
Before the risky dive into the trench, James Cameron said that he wanted to see with his own eyes at least part of the secrets of the Mariana Trench, about which there are so many rumors and legends. But he did not see anything that went beyond the knowable. 
So what do we know about her?
To understand how the Mariana underwater gap was formed, it should be remembered that such gaps (trenches) are usually formed along the edges of the oceans under the influence of moving lithospheric plates. Oceanic plates, being older and heavier, “crawl” under continental plates, forming deep gaps at the junctions. The deepest is the junction of the Pacific and Philippine tectonic plates near the Mariana Islands (Mariana Trench). The Pacific plate is moving at a rate of 3-4 centimeters per year, resulting in increased volcanic activity along both its edges. 
Along the entire length of this deepest failure, four so-called bridges—transverse mountain ridges—were discovered. The ridges were presumably formed due to the movement of the lithosphere and volcanic activity. 
The gutter is V-shaped in cross-section, greatly expanding at the top and narrowing downwards. The average width of the canyon in the upper part is 69 kilometers, in the widest part - up to 80 kilometers. The average width of the bottom between the walls is 5 kilometers. The slope of the walls is almost vertical and is only 7-8°. The depression stretches from north to south for 2,500 kilometers. The trench has an average depth of about 10,000 meters. 
Only three people to date have visited the very bottom of the Mariana Trench. In 2018, another manned dive to the “bottom of the world” in its deepest section is planned. This time, the famous Russian traveler Fyodor Konyukhov and polar explorer Artur Chilingarov will try to conquer the depression and find out what it hides in its depths. Currently, a deep-sea bathyscaphe is being manufactured and a research program is being drawn up.
There is an underwater canyon off the east coast of the Philippine Islands. It's so deep that you could fit Mount Everest in it and still have about three kilometers to spare. There is impenetrable darkness and incredible pressure, so you can easily imagine the Mariana Trench as one of the most unfriendly places in the world. However, despite all this, life still somehow continues to exist there - and not just barely survive, but actually thrive, thanks to which a full-fledged ecosystem has appeared there.
Life at such a depth is extremely difficult - eternal cold, impenetrable darkness and enormous pressure will not allow you to exist in peace. Some creatures, such as the anglerfish, create their own light to attract prey or mates. Others, such as the hammerhead, have developed huge eyes to capture as much light as possible, reaching incredible depths. Other creatures are simply trying to hide from everyone, and to achieve this they turn translucent or red (the red color absorbs all the blue light that manages to make its way to the bottom of the cavity).
Cold protection
It is also worth noting that all creatures living at the bottom of the Mariana Trench need to cope with cold and pressure. Protection from cold is provided by fats that form the lining of the creature's body cells. If this process is not monitored, the membranes may crack and cease to protect the body. To combat this, these creatures have acquired an impressive supply of unsaturated fats in their membranes. With the help of these fats, the membranes always remain in a liquid state and do not crack. But is this enough to survive in one of the deepest places on the planet?
What is the Mariana Trench like?
The Mariana Trench is shaped like a horseshoe and its length is 2,550 kilometers. It is located in the eastern Pacific Ocean and is about 69 kilometers wide. The deepest point of the depression was discovered near the southern end of the canyon in 1875 - the depth there was 8184 meters. A lot of time has passed since then, and with the help of an echo sounder more accurate data was obtained: it turns out that the deepest point has an even greater depth, 10994 meters. It was named “Challenger Deep” in honor of the ship that made that very first measurement.
Human immersion
However, about 100 years have passed since that moment - and only then for the first time a person plunged to such a depth. In 1960, Jacques Piccard and Don Walsh set off in the bathyscaphe Trieste to conquer the depths of the Mariana Trench. Trieste used gasoline as fuel and iron structures as ballast. The bathyscaphe took 4 hours and 47 minutes to reach a depth of 10,916 meters. It was then that the fact that life still exists at such depths was first confirmed. Piccard reported that he then saw a “flat fish,” although in fact it turned out that he only noticed a sea cucumber.
Who lives at the bottom of the ocean?
However, not only sea cucumbers are found at the bottom of the depression. Along with them live large single-celled organisms known as foraminifera - they are giant amoebas that can grow up to 10 centimeters in length. Under normal conditions, these organisms create shells of calcium carbonate, but at the bottom of the Mariana Trench, where the pressure is a thousand times greater than on the surface, calcium carbonate dissolves. This means that these organisms have to use proteins, organic polymers and sand to create their shells. Also living at the bottom of the Mariana Trench are shrimp and other crustaceans known as amphipods. The largest amphipods look like giant albino woodlice and can be found in the Challenger Deep.
Food at the bottom
Considering that sunlight does not reach the bottom of the Mariana Trench, another question arises: what do these organisms eat? Bacteria manage to survive at such depths because they feed on methane and sulfur that emerge from the earth's crust, and some organisms feed on these bacteria. But many rely on what is called "sea snow" - tiny pieces of detritus that reach the bottom from the surface. One of the most striking examples and the richest sources of food are the carcasses of dead whales, which as a result end up on the ocean floor.
Fishes in the Trench
But what about fish? The deepest fish in the Mariana Trench was discovered only in 2014 at a depth of 8143 meters. An unknown ghostly white subspecies of Liparidae with wide wing-like fins and an eel-like tail was recorded several times by cameras that plunged into the depths of the depression. However, scientists believe this depth is likely the limit of where the fish can survive. This means that there cannot be fish at the bottom of the Mariana Trench, since the conditions there do not correspond to the body structure of vertebrate species.