The Mariana Trench, or Mariana Trench, is an oceanic trench in the western Pacific Ocean,
being the deepest geographical feature known on Earth.
The depression stretches along the Mariana Islands for 1500 km; it has a V-shaped profile,
steep (7-9°) slopes, 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.
Research into the Mariana Trench began with the British expedition of the Challenger, which carried out the first systematic measurements of the depths of the Pacific Ocean. This military three-masted corvette with sail equipment was rebuilt into an oceanographic vessel for hydrological, geological, chemical, biological and meteorological work in 1872. Also, significant contributions to the study of the Marianas deep-sea trench were 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. In 1960, the bathyscaphe Trieste was immersed to the bottom Mariana Trench to a depth of 10915 m. 
The device recording sounds began to transmit to the surface noises reminiscent of the grinding of saw teeth on metal. At the same time, unclear shadows appeared on the TV monitor, similar to giant fairy-tale dragons. These creatures had several heads and tails. An hour later, scientists on the American research vessel Glomar Challenger became worried that the unique equipment, made from beams of ultra-strong titanium-cobalt steel in a NASA laboratory, having a spherical structure, the so-called “hedgehog” with a diameter of about 9 m, could remain in the abyss forever. The decision was made to raise it immediately. It took more than eight hours for the “hedgehog” to be recovered from the depths. As soon as he appeared on the surface, he was immediately placed on a special raft. The television camera and echo sounder were lifted onto the deck of the Glomar Challenger. It turned out that the strongest steel beams of the structure were deformed, and the 20-centimeter steel cable on which it was lowered was half sawn through. Who tried to leave the “hedgehog” at depth and why is an absolute mystery. Details of this interesting experiment conducted by American oceanologists in the Mariana Trench were published in 1996 in the New York Times (USA).
This is not the only case of a collision with the inexplicable in the depths of the Mariana Trench. Something similar happened to the German research vehicle Haifish with a crew on board. Once at a depth of 7 km, the device suddenly refused to float. Finding out the cause of the problem, the hydronauts turned on the infrared camera. What they saw in the next few seconds seemed to them a collective hallucination: a huge prehistoric lizard, sinking its teeth into the bathyscaphe, tried to chew it like a nut. Having come to their senses, the crew activated a device called an “electric gun.” The monster, struck by a powerful discharge, disappeared into the abyss. 
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 they are pressed by huge masses of ocean waters, the pressure of which 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, oceanographers considered the hypothesis that life could exist at depths of more than 6,000 m in impenetrable darkness, under enormous pressure and at temperatures close to zero, to be crazy. 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 living organisms pogonophora ((pogonophora; from the Greek pogon - beard and phoros - bearing), a type of marine invertebrate animals living in long chitinous tubes open at both ends). Recently, the veil of secrecy has been 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), - from 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 organisms - 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, mutant octopuses, extraordinary sea stars and some soft-bodied creatures two meters long, which have not yet been identified at all. 
So, man has never been able to resist the desire to explore the unknown, and the rapidly developing world of technological progress allows us to penetrate ever deeper into the secret world of the most inhospitable and rebellious environment in the world - the World Ocean. There will be enough research items in the Mariana Trench for many years to come.
The ocean abyss knows how to keep its secrets. Will people be able to reveal them in the near future? 
While at the very high point Thousands of people visited the planet, Everest, but only three descended to the bottom of the Mariana Trench. This is the least explored place on Earth; there are many mysteries around it. Last week, geologists found that over a million years, 79 million tons of water penetrated into the bowels of the Earth through a fault at the bottom of the depression.
What happened to her after this is unknown. “High-tech” talks about the geological structure of the lowest point on the planet and the strange processes that occur at its bottom.
Without sun rays and under enormous pressure
The Mariana Trench is not a vertical abyss. This is a crescent-shaped trench stretching for 2.5 thousand km east of the Philippines and west of Guam, USA. The deepest point of the trench, the Challenger Deep, is located 11 km from the surface of the Pacific Ocean. Everest, if it were at the bottom of the depression, would be 2.1 km short of sea level.
Map of the Mariana Trench.
The Mariana Trench (as the trench is also commonly called) is part of a global network of troughs that cross the seabed and were formed as a result of ancient geological events. They arise when two tectonic plates collide, when one layer sinks under the other and goes into the Earth's mantle.
The underwater trench was discovered by the British research ship Challenger during the first global oceanographic expedition. In 1875, scientists tried to measure the depth with a diplot - a rope with a weight tied to it and meter markings. The rope was only enough for 4,475 fathoms (8,367 m). Almost a hundred years later, the Challenger II returned to the Mariana Trench with an echo sounder and established the current depth of 10,994 m.
The bottom of the Mariana Trench is hidden in eternal darkness - the sun's rays do not penetrate to such a depth. Temperatures are just a few degrees above zero - and close to freezing. The pressure in the Challenger Deep is 108.6 MPa, which is approximately 1,072 times the normal atmospheric pressure at ocean level. This is five times the pressure that is created when a bullet hits a bulletproof object and is approximately equal to the pressure inside the reactor for the synthesis of polyethylene. But people found a way to get to the bottom.
Man in the Deep
The first people to visit the Challenger Abyss were American soldiers Jacques Piccard and Don Walsh. In 1960, on the Trieste bathyscaphe, they descended to 10,918 m in five hours. The researchers spent 20 minutes at this mark and saw almost nothing because of the clouds of silt raised by the device. Except for the fish of the flounder species, which was hit by the spotlight. The presence of life under such high pressure was the main discovery of the mission.
Before Piccard and Walsh, scientists believed that fish could not live in the Mariana Trench. The pressure in it is so great that calcium can only exist in liquid form. This means that vertebrate bones must literally dissolve. No bones, no fish. But nature showed scientists that they were wrong: living organisms are capable of adapting even to such unbearable conditions.
Many living organisms in the Challenger Abyss were discovered by the Deepsea Challenger bathyscaphe, on which director James Cameron descended alone to the bottom of the Mariana Trench in 2012. In soil samples taken by the apparatus, scientists found 200 species of invertebrates, and at the bottom of the depression - strange translucent shrimp and crabs.
At a depth of 8 thousand m, the submersible discovered the deepest-sea fish - a new representative of the species of lipariformes or sea slugs. The head of the fish resembles that of a dog, and its body is very thin and elastic - when moving, it resembles a translucent napkin that is carried by the current.
A few hundred meters below live giant ten-centimeter amoebas called xenophyophores. These organisms show amazing resistance to several elements and chemicals such as mercury, uranium and lead that would kill other animals or humans within minutes.
Scientists believe there are many more species in the depths waiting to be discovered. In addition, it is still not clear how such microorganisms - extremophiles - can survive in such extreme conditions.
The answer to this question will lead to breakthroughs in biomedicine and biotechnology and will help understand how life began on Earth. For example, researchers from the University of Hawaii believe that thermal mud volcanoes near the depression may have provided conditions for the survival of the first organisms on the planet.
Volcanoes at the bottom of the Mariana Trench.
What kind of rift?
The depression owes its depth to the fault of two tectonic plates - the Pacific layer goes under the Philippine one, forming a deep trench. Regions in which such events occurred geological events, is called a subduction zone.
Each plate is almost 100 km thick and the fault is at least 700 km deep from the lowest point of the Challenger Deep. “It's an iceberg. The man wasn't even at the top - 11 are nothing compared to the 700 hiding in the depths. The Mariana Trench is the boundary between the limits of human knowledge and a reality that is inaccessible to humans,” says geophysicist Robert Stern from the University of Texas.
Plates at the bottom of the Mariana Trench.
Scientists suggest that large volumes of water enter the Earth's mantle through the subduction zone - rocks at the boundaries of faults act like sponges, absorbing water and transporting it into the bowels of the planet. As a result, the substance ends up at a depth of 20 to 100 km below the seabed.
Geologists from the University of Washington found that over the last million years, more than 79 million tons of water entered the bowels of the earth through the joint - this is 4.3 times more than previous estimates.
The main question is what happens to the water in the depths. It is believed that volcanoes close the water cycle, returning water to the atmosphere in the form of water vapor during eruptions. This theory was supported by previous measurements of the volume of water penetrating the mantle. Volcanoes ejected into the atmosphere approximately equal to the absorbed volume.
A new study disproves this theory - estimates suggest that the Earth absorbs more water than it returns. And this is really strange - given that the level of the World Ocean over the past few hundred years not only has not decreased, but has even increased by several centimeters.
A possible solution is to abandon the theory of equal carrying capacity of all subduction zones on Earth. Conditions in the Mariana Trench are likely more extreme than in other parts of the planet, and more water penetrates into the subsurface through the Challenger Deep rift.
“Does the amount of water depend on the structural features of the subduction zone, for example, on the angle of bending of the plates? We hypothesize that similar faults exist in Alaska and Latin America, but so far man has not been able to discover a deeper structure than the Mariana Trench,” added lead author of the study Doug Vines.
Water hiding in the bowels of the Earth is not the only mystery of the Mariana Trench. The US National Oceanic and Atmospheric Administration (NOAA) calls the region an amusement park for geologists.
This is the only place on the planet where carbon dioxide exists in liquid form. It is ejected from several submarine volcanoes located outside the Okinawa Trough near Taiwan.
At a depth of 414 m in the Mariana Trench is the Daikoku volcano, which is a lake of pure sulfur in liquid form, which constantly boils at a temperature of 187 ° C. 6 km below are geothermal springs that release water at a temperature of 450 °C. But this water does not boil - the process is hampered by the pressure exerted by the 6.5-kilometer water column.
The ocean floor is currently less studied by humans than the Moon. Scientists will probably be able to discover faults deeper than the Mariana Trench, or at least study its structure and features.
The Mariana Trench is located in the western part of the Pacific Ocean, not far from the Mariana Islands, just two hundred kilometers away, thanks to its proximity to which it received its name. It is a huge marine reserve with the status of a US national monument, and therefore is under state protection. Fishing and mining are strictly prohibited here, but you can swim and admire the beauty.
The shape of the Mariana Trench resembles a colossal crescent - 2550 km long and 69 km wide. The deepest point - 10,994 m below sea level - is called the Challenger Deep.
Discovery and first observations
The British began to explore the Mariana Trench. In 1872, the sailing corvette Challenger entered the waters of the Pacific Ocean with scientists and the most advanced equipment of those times. After taking measurements, we established the maximum depth - 8367 m. The value, of course, is noticeably different from the correct result. But this was enough to understand: the deepest point on the globe had been discovered. Thus, another mystery of nature was “challenged” (translated from English as “Challenger” - “challenger”). Years passed, and in 1951 the British carried out “work on the mistakes.” Namely: the deep-sea echo sounder recorded a maximum depth of 10,863 meters.
Then the baton was intercepted by Russian researchers, who sent the research vessel Vityaz to the Mariana Trench area. In 1957, with the help of special equipment, they were not only able to record the depth of the depression as 11,022 m, but also established the presence of life at a depth of more than seven kilometers. Thus, making a small revolution in the scientific world of the mid-20th century, where there was a strong opinion that there are no and cannot be such deeply living creatures. This is where the fun begins... Many stories about underwater monsters, huge octopuses, unprecedented bathyscaphes crushed into a cake by the huge paws of animals... Where is the truth and where is the lie - let's try to figure it out.
Secrets, riddles and legends
The first daredevils who dared to dive to the “bottom of the Earth” were US Navy Lieutenant Don Walsh and explorer Jacques Picard. They dived on the bathyscaphe "Trieste", which was built in the Italian city of the same name. A very heavy structure with thick 13-centimeter walls was immersed in the bottom for five hours. Having reached the lowest point, the researchers stayed there for 12 minutes, after which an ascent was immediately begun, which took approximately 3 hours. At the bottom, fish were found - flat, flounder-like, about 30 centimeters long.
Research continued, and in 1995 the Japanese descended into the “abyss”. Another “breakthrough” was made in 2009 with the help of automatic underwater vehicle"Nereus": this miracle of technology not only took several photographs at the deepest point of the Earth, but also took soil samples.
In 1996, the New York Times published shocking material about the diving of equipment from the American scientific vessel Glomar Challenger into the Mariana Trench. The team affectionately nicknamed the spherical apparatus for deep-sea travel “the hedgehog.” Some time after the start of the dive, the instruments recorded terrifying sounds reminiscent of the grinding of metal on metal. “The Hedgehog” was immediately raised to the surface, and they were horrified: the huge steel structure was crushed, and the strongest and thickest (20 cm in diameter!) cable seemed to have been sawed off. Many explanations were immediately found. Some said that these were the “tricks” of the monsters inhabiting the natural object, others were inclined to the version of the presence of an alien intelligence, and still others believed that it could not have happened without mutated octopuses! True, there was no evidence, and all assumptions remained at the level of conjecture and conjecture...
The same mysterious incident occurred with a German research team that decided to lower the Haifish apparatus into the waters of the abyss. But for some reason he stopped moving, and the cameras impartially displayed on the monitor screens an image of the shocking size of a lizard that was trying to chew through the steel “thing.” The team was not at a loss and “scared away” the unknown beast with an electric discharge from the device. He swam away and never appeared again... One can only regret that for some reason those who came across such unique inhabitants of the Mariana Trench did not have the equipment that would allow them to photograph them.
At the end of the 90s of the last century, at the time of the “discovery” of the monsters of the Mariana Trench by the Americans, the “fouling” of this geographical feature legends. Fishermen (poachers) talked about glows from its depths, lights running back and forth, and various unidentified flying objects floating up from there. Crews of small ships reported that ships in the area were being “towed at great speed” by a monster possessing incredible strength.
Confirmed evidence
Depth of the Mariana TrenchAlong with many legends associated with the Mariana Trench, there are also incredible facts, supported by irrefutable evidence.
Found a giant shark toothIn 1918, Australian lobster fishermen reported seeing a transparent white fish about 30 meters long in the sea. According to the description, it looks like ancient shark species Carcharodon megalodon, which lived in the seas 2 million years ago. Scientists from the surviving remains were able to recreate the appearance of a shark - a monstrous creature 25 meters long, weighing 100 tons and an impressive two-meter mouth with teeth 10 cm each. Can you imagine such “teeth”! And it was they who were recently found by oceanologists at the bottom of the Pacific Ocean! The “youngest” of the discovered artifacts… is “only” 11 thousand years old!
This find allows us to be sure that not all megalodons went extinct two million years ago. Perhaps the waters of the Mariana Trench hide these incredible predators from human eyes? Research continues; the depths still conceal many unsolved secrets.
Features of the deep sea world
The water pressure at the lowest point of the Mariana Trench is 108.6 MPa, which is higher than normal Atmosphere pressure 1072 times. A vertebrate animal simply cannot survive in such monstrous conditions. But, oddly enough, mollusks have taken root here. How their shells withstand such colossal water pressure is unclear. The discovered mollusks are an incredible example of “survival”. They exist next to serpentine hydrothermal vents. Serpentine contains hydrogen and methane, which not only do not pose a threat to the “population” found here, but also contribute to the formation of living organisms in such a seemingly aggressive environment. But hydrothermal springs also emit gas that is lethal to shellfish - hydrogen sulfide. But “cunning” and life-hungry mollusks have learned to process hydrogen sulfide into protein, and continue, as they say, to live happily in the Mariana Trench.
Another incredible mystery of a deep-sea object is the Champagne hydrothermal spring, named after the famous French (and not only) alcoholic drink. It's all about the bubbles that “bubble” in the waters of the source. Of course, these are by no means bubbles of your favorite champagne - these are liquid carbon dioxide. Thus, the only underwater source of liquid carbon dioxide in the entire world is located precisely in the Mariana Trench. Such sources are called “white smokers”, their temperature is lower than environment, and there are always fumes around them that look like white smoke. Thanks to these sources, hypotheses were born about the origin of all life on earth in water. Low temperature, an abundance of chemicals, colossal energy - all this created excellent conditions for ancient representatives of flora and fauna.
The temperature in the Mariana Trench is also very favorable - from 1 to 4 degrees Celsius. “Black smokers” took care of this. Hydrothermal springs, the antipode of “white smokers,” contain a large number of ore substances, and therefore they are dark in color. These springs are located here at a depth of about 2 kilometers and spew out water whose temperature is about 450 degrees Celsius. I immediately remember a school physics course, from which we know that water boils at 100 degrees Celsius. So what's going on? Is the spring spewing boiling water? Fortunately, no. It's all about the colossal water pressure - it is 155 times higher than on the surface of the Earth, so H 2 O does not boil, but it significantly “heats up” the waters of the Mariana Trench. The water of these hydrothermal springs is incredibly rich in various minerals, which also contributes to the comfortable habitat of living creatures.
Incredible facts
How many more mysteries and incredible wonders does this incredible place conceal? A bunch of. At a depth of 414 meters, the Daikoku volcano is located here, which served as further evidence that life originated here, at the deepest point of the globe. In the crater of the volcano, underwater, there is a lake of pure molten sulfur. In this “boiler”, sulfur bubbles at a temperature of 187 degrees Celsius. The only known analogue of such a lake is located on Jupiter’s satellite Io. There is nothing else like it on Earth. Only in space. It is no wonder that most hypotheses about the origin of life from water are associated precisely with this mysterious deep-sea object in the vast Pacific Ocean.
Let's remember a little school biology course. The simplest living creatures are amoebas. Tiny, single-celled, they can only be seen through a microscope. They reach, as it is written in textbooks, a length of half a millimeter. Giant toxic amoebas 10 centimeters long were discovered in the Mariana Trench. Can you imagine this? Ten centimeters! That is, this single-celled Living being can be clearly seen with the naked eye. Isn't this a miracle? As a result scientific research It has been established that amoebas acquired such gigantic sizes for their class of single-celled organisms by adapting to the “unsweetened” life at the bottom of the sea. Cold water coupled with its colossal pressure and the absence of sunlight contributed to the “growth” of amoebas, which are called xenophyophores. The incredible abilities of xenophyophores are quite surprising: they have adapted to the effects of most destructive substances - uranium, mercury, lead. And they live in this environment, just like mollusks. In general, the Mariana Trench is a miracle of miracles, where everything living and nonliving is perfectly combined, and the most harmful chemical elements that can kill any organism not only do not harm living things, but, on the contrary, promote survival.
The local bottom has been studied in some detail and is not of particular interest - it is covered with a layer of viscous mucus. There is no sand there, there are only the remains of crushed shells and plankton that have been lying there for thousands of years, and due to water pressure have long since turned into thick grayish-yellow mud. And the calm and measured life of the seabed is disturbed only by the bathyscaphes of researchers that descend here from time to time.
Inhabitants of the Mariana Trench
Research continues
Everything secret and unknown has always attracted man. And with each secret revealed, new mysteries on our planet did not become fewer. All this fully applies to the Mariana Trench.
At the end of 2011, researchers discovered unique natural stone formations in it, shaped like bridges. Each of them stretched from one end to the other for as much as 69 km. Scientists had no doubt: this is where the tectonic plates – the Pacific and the Philippine – come into contact, and stone bridges (four in total) were formed at their junction. True, the very first of the bridges - Dutton Ridge - was opened in the late 80s of the last century. He impressed then with his size and height, which were the size of a small mountain. At its highest point, located just above the Challenger Deep, this deep-sea “ridge” reaches two and a half kilometers.
Why did nature need to build such bridges, and even in such a mysterious and inaccessible place for people? The purpose of these objects still remains unclear. In 2012, James Cameron, the creator of legendary film"Titanic". Unique equipment and powerful cameras installed on his DeepSea Challenge bathyscaphe made it possible to film the majestic and deserted “bottom of the Earth.” It is unknown how long he would have been observing local landscapes if some problems had not arisen on the device. In order not to risk his life, the researcher was forced to rise to the surface.
Together with The National Geographic, the talented director created the documentary film “Challenging the Abyss.” In his story about the dive, he called the bottom of the depression “the border of life.” Emptiness, silence, and nothing, not the slightest movement or disturbance of the water. No sunlight, no shellfish, no algae, much less sea monsters. But this is only at first glance. Over twenty thousand different microorganisms were found in the bottom soil samples taken by Cameron. Great amount. How do they survive under such incredible water pressure? Still a mystery. Among the inhabitants of the depression, a shrimp-like amphipod was also discovered that produces a unique chemical substance that scientists are testing as a vaccine against Alzheimer's disease.
While staying at the deepest point not only of the world's oceans, but of the entire Earth, James Cameron did not encounter any terrible monsters, or representatives of extinct animal species, or an alien base, not to mention any incredible miracles. The feeling that he was completely alone here was a real shock. The ocean floor seemed deserted and, as the director himself said, “lunar... lonely.” The feeling of complete isolation from all humanity was such that it cannot be expressed in words. However, he still tried to do this in his documentary film. Well, you probably shouldn’t be surprised that the Mariana Trench is silent and shocking with its desolation. After all, she simply sacredly guards the secret of the origin of all life on Earth...
The Mariana Trench (or Mariana Trench) became known in 1875, when the British survey ship Challenger first explored the depth of this place using a deep-sea survey.
The ship's crew was probably very surprised when they unwound kilometers of rope so that the cargo could finally reach the bottom. Based on the results of the study, it was determined that at the deepest point the bottom is located at a distance of 8,367 meters from the surface of the ocean.
In 1951, a new British expedition on the Challenger 2 ship, using an echo sounder, determined the depth of the depression at 10,863 ± 100 meters. The depth of the bottom varies depending on its topography. Since then, the deepest point on the planet has been called the Challenger Deep.
Progress moved forward, and people began to think about visiting the bottom of the Mariana Trench using a manned deep-sea vehicle.
The first human dive to the bottom of the Mariana Trench. Project "Nekton"
The first two people in history to reach the deepest point on earth were Swiss scientist Jacques Piccard and US Navy Lieutenant Don Walsh.
The device, which made it possible to dive under extreme pressure conditions, was named “Trieste” and was originally built by two Swiss scientist-enthusiasts - Auguste Picard and his son Jacques Picard. After a series of successful dives in the Mediterranean Sea, Trieste was purchased by the US Navy, which was interested in exploring the ocean depths. After modernizing the bathyscaphe, installing a heavy-duty gondola and modern navigation and electronic systems, Trieste was ready to conquer new depths.
The target for the dive was chosen to be no less than the deepest point on the globe. The project, called Necron, planned to take two people to the bottom of the Challenger Deep in the Mariana Trench and carry out scientific research on the site. On January 23, 1960, at 08:23 local time, the Trieste, with Jacques Piccard and Don Walsh on board, began its slow descent into darkness. After 4 hours 43 minutes, the submersible touched the bottom at a distance of 10,919 meters from the ocean surface.
For the first time, a person found himself at the bottom of the deepest place on the planet. The pressure, 1072 times higher than normal, squeezed the nacelle of the bathyscaphe with terrible force.
The researchers stayed at the bottom for 20 minutes, during which they conducted a number of scientific experiments to measure radiation, measured the water temperature, which was 3.3 °C (the air temperature in the gondola was 4.5 °C), took a large number of photographs of the ocean floor and even we saw a small fish that looked like a flounder.
After dropping the ballast, the bathyscaphe began its ascent, which lasted 3 hours 27 minutes.
For 52 long years, no one else conquered the Mariana Trench, limiting themselves only to the descent of automatic robots into the Challenger Abyss.
Conquest of the Mariana Trench by James Cameron
Who would have thought that the next person who, for the first time in many years, would decide to visit the bottom of the Mariana Trench would not be some ocean scientist, but the famous Hollywood director James Cameron! On March 26, 2012, Cameron dived to a depth of 10,908 meters on the Deepsea Challenger submersible.
Bathyscaphe Deepsea Challenger | The Deepsea Challenger bathyscaphe, containing the latest scientific equipment and 3D cameras, implies the presence of only one pilot in the cockpit, but allows you to stay under water for up to 56 hours and freely maneuver on the ocean floor using 12 electric motors. Its creation, taking into account the design stage, took almost 7 years, and construction was carried out by a private Australian company.
During the study of the bottom of the Mariana Trench, the director conducted video and photography, and also, using manipulators, took samples of ocean soil, where, as it turned out later, microorganisms previously unknown to science were present.
Currently James Cameron is the third and last person, who visited the deepest point of the planet - the Challenger Deep at the very bottom of the Mariana Trench. In total, only two underwater vehicles with people on board sank to the bottom of the Mariana Trench.
Illustration: depositphotos.com | tolokonov
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The Mariana Trench (or Mariana Trench) is the deepest place 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 ocean depths. 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 for a long time tried to find out its true depth. Research different years gave different meanings. 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 together with echo sounders different levels, in 2011, the depth value in the Challenger Deep was established as 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 opening 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 the upward flow of water also had important ecological significance: based on it, nuclear powers refused to bury 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 “warm up” icy waters, supporting life in the abyss - the temperature at the bottom of the Mariana Trench is within 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 mucus from organic sediments descending from upper layers 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 aggressive, destructive normal conditions environment 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 live at different depths different types living organisms. The more deep sea inhabitants abyss, the better their organs of vision are developed, 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 They are increasingly losing 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.