Monsters at the bottom of the Mariana Trench. Mysteries of the Mariana Trench

Mariana Trench- this is a deep-sea trench, located in the west Pacific Ocean near the Mariana Islands (from which it takes its name). It contains the lowest known to science the point of our planet is the Challenger abyss, the depth of which reaches almost 11 kilometers below sea level. The most accurate and latest measurements recorded a depth of 10,994 meters, but this figure may have an error of a couple of tens of meters. It is noteworthy that the highest point on Earth (Mount Chomolungma) is only 8.8 kilometers above sea level. Therefore, it can be completely placed in the Mariana Trench, and there will be several more kilometers of water above it. Such scale is really amazing.

Why the depression is difficult to study

The maximum depth that a person without equipment can withstand is a little more than 100 meters, although even this figure is truly a record. So special equipment scuba divers reached a maximum of 330 meters. This is 33 times less than the depth of the Mariana Trench, and the pressure at its bottom is 1000 times higher than normal for a person. Consequently, immersion to the bottom of the gutter is beyond human strength.

The first thing that comes to mind to remedy this situation is to use special devices and mechanisms that can go down and get back up unscathed. But even here there are difficulties. Water pressure bends even metal, so the walls of a deep-sea vehicle must be thick and strong. After diving, the device needs to somehow emerge, and this requires a huge compartment with air.

The scientists managed to overcome the above difficulties: they created a special research bathyscaphe. He is able to plunge into the abyss of the Challenger, and even a person can be in it. But there is one more serious problem. Not a single ray penetrates to the bottom of the gutter sunlight, and the density of water is so high that the illumination from the bathyscaphe's lanterns barely breaks through it. Consequently, a ship that has landed at the very bottom illuminates environment just a few meters around.

The length of the Mariana Trench is more than 2.5 kilometers, its width is 69 kilometers, and the entire relief is extremely uneven and covered with numerous hills. It will take tens and hundreds of years to simply look through the camera every meter of the bottom of the depression. That is why the study of the deep-sea trench causes so many difficulties. Scientists receive information about underwater world in small pieces, making films and collecting samples of living organisms from the bottom.

Research history

In 1951, the deepest point of the depression was measured quite accurately. A hydrographic vessel called Challenger 2, using special devices, recorded that the bottom was 10,899 meters below sea level. Over time, the data was corrected, but the name of the lowest point on the planet from those studies is the name of the ship that studied it.

In 1960, people first decided to dive to the bottom of the Mariana Trench. The daredevils were D. Walsh and J. Picard, American researchers. Having plunged to the bottom of the gutter in the Trieste bathyscaphe, they were surprised to see a strange-looking flat fish. Up to this point, it was believed that such a huge pressure of water could not withstand any creature, so the discovery of scientists has become a real sensation. Only one person repeated their feat - in 2012, the famous director James Cameron plunged into the abyss of the Challenger alone, filming unique footage that formed a separate documentary.

In 1995, the Japanese plunged into the abyss a remote-controlled probe "Kaiko", which collected samples of flora from the bottom. Testate unicellular organisms were found in the samples. In 2009, the Nerius underwater research apparatus was sent to the deep sea. He transmitted information about the plants and creatures around him with the help of LED lamps and special cameras, and, in addition, he collected the biological material he encountered in a large container.

open views

The Mariana Trench is home to many animals, from appearance which give goosebumps. However, despite the terrifying appearance, most of them are not dangerous to humans.

smallmouth macropinna- a deep-sea fish with a very strange head. Her large green eyes are located in a liquid surrounded by a transparent shell. The eyes can rotate in different directions, which provides the fish with quite wide angle review. This creature feeds on zooplankton. It is noteworthy that the macropinna could not be studied for a very long time, because her head bursts from the pressure as she floats to the surface of the water.

The goblin shark is a rather unpleasant-looking shark with a huge outgrowth on its muzzle in the form of a hooked nose. Due to the thin skin, the shark's blood vessels show through, giving it a light pink color. This is one of the least studied species of sharks, as it lives at decent depths.

Iglorot is a small deep-sea fish, which, however, looks intimidating. On her body there is a small process, the tip of which glows, luring prey - small fish and crustaceans. The teeth of the fish are long and thin, which is why it got its name.

Grimpoteuthis, or Dumbo octopus, is perhaps one of the few deep-sea species that cause not fear, but tenderness. Lateral processes on his body resemble big ears elephant Dumbo, for which the creature got its name.

Hatchet fish got its nickname because of its resemblance to an axe. It has a very small size - from 2 to 15 cm, and feeds on smaller species of fish, shrimps and crustaceans. The fish emits a slight greenish glow.

Mysteries of the Hollow and Monster Myths

One of the strangest and most unexplored features of the Mariana Trench is that in its depths, the level of radiation is greatly increased. It is emitted even by some species of crustaceans and fish. Scientists cannot explain where the radiation came from at such depths. In addition, the water in the Challenger Abyss is heavily contaminated with toxins, although the area near the trough is strictly guarded and there are no reports of any industrial waste dumped into the ocean in this place, and there can be no question.

In 1996, the bathyscaphe Glomar Challenger was immersed in the depths of the Pacific Ocean in the Mariana Trench. Some time after the start of the study, the team heard strange sounds from the speakers, as if someone was trying to saw through the metal. Scientists immediately began to raise the ship to the surface, and it was badly mangled and crushed. The table cable attached to the bathyscaphe was almost completely sawn. The cameras captured huge silhouettes, similar to sea dragons from the most terrible fairy tales.

A few years later, a similar incident occurred with the Highfish submersible. Having descended to a certain depth, the bathyscaphe stopped rising and falling. Turning on the cameras, the scientists saw that the ship was holding a strange monster with its teeth, similar to huge lizard. Perhaps members of both expeditions saw the same creature. Unfortunately, there is no documentary evidence of this.

In the early 2000s, an incredible tooth was discovered in the Pacific Ocean. Scientists have determined that it belongs to a giant shark, supposedly extinct several million years ago - Megalodon. However, the material found in the ocean is no older than 20,000 years. On the scale of evolution and biology, such a period is considered very small, so the researchers believe that the 24-meter prehistoric shark may still be alive.

Nevertheless, information about giant and terrifying creatures in the abyss of the Pacific Ocean at this stage in the development of oceanology can be safely called myths. It is possible that some of these creatures really exist, but until scientists can study at least a few dozen individuals, it is too early to talk about their existence. In addition, about 10 thousand of its representatives are required to maintain the population of the species. If only so many people lived in the abyss giant monsters, they would be much more common. Currently, only eyewitnesses and damage to some submarines testify to these creatures.

The Mariana Trench is a crescent-shaped trench in the western Pacific Ocean, east of the Mariana Islands near Guam. The region surrounding the trench is notable for many unique natural conditions. The Mariana Trench contains the deepest known points on Earth, vents seething with liquid sulfur and carbon dioxide, active mud volcanoes and marine life, adapted to pressures 1000 times greater than at sea level.

The Challenger Deep, in the southern part of the Mariana Trench, is the deepest place in the ocean. Its depth is difficult to measure from the surface.

In 2010, the Challenger Deep was reported to be 10,994 m (36,070 ft) deep, measured by sound pulses sent across the ocean during a 2010 survey by the National Oceanic and Atmospheric Administration (NOAA).

In 2012, filmmaker and explorer James Cameron sank to the bottom of the Challenger Deep, reaching 10,898 meters during the 2012 expedition. But he could have gone a little deeper. Cartographic survey of the seabed with high resolution, published in 2014 by researchers at the University of New Hampshire, showed that the bottom of the Challenger Deep was at a depth of 36,037 feet (10,984 m).

The second deepest place in the ocean is also located in the Mariana Trench. The depth of the siren (Sirena Deep), which lies 200 km east of the Challenger Deep, is 10,809 m.

For comparison, Mount Everest stands at 8,848 meters above sea level, which means that the deepest part of the Mariana Trench is 2,147 meters deeper than Mount Everest.

Where is the Mariana Trench

The Mariana Trench is 2,542 kilometers long, more than five times the length Grand Canyon. However, the trough averages 69 km wide.

Because Guam is a US territory and the 15 Northern Mariana Islands are a US commonwealth, the United States has jurisdiction over the Mariana Trench. In 2009, President George W. Bush established the Mariana Marine National Monument, which created a protected marine reserve covering about 506,000 square kilometers of seabed and waters surrounding the outlying islands. It includes most Mariana Trench, 21 underwater volcanoes and areas around three islands.

How was the Mariana Trench formed?

The Mariana Trench was created as a result of a process occurring in a subduction zone where two massive plates of oceanic crust collide. In the subduction zone, one piece of oceanic crust is pushed and pulled under another, sinking into the Earth's mantle, the layer beneath the crust. Where two pieces of bark intersect, a deep trough forms over a bend in the sinking bark. In this case, the Pacific Ocean's crust bends below the Philippine crust.

The Pacific crust, also called the tectonic plate, is about 180 million years old. The Philippine Plate is younger and smaller than the Pacific. In subduction zones, the cold, dense crust sinks back into the mantle and collapses there.

As deep as the trench is, it is not the closest place to the center of the Earth. Since the planet bulges out at the equator, the radius at the poles is about 25 km less than the radius at the equator. Thus, parts of the seabed of the Arctic Ocean are closer to the center of the Earth than the depth of the Challenger.

The water pressure at the bottom of the trench is over 8 tons per square inch (703 kg per square meter). This is more than 1,000 times the pressure felt at sea level, or the equivalent of 50 jet planes stacked on top of a person.

Unusual volcanoes in the Mariana Trench

The chain of volcanoes rising above the ocean waves and forming the Mariana Islands reflects the crescent-shaped arc of the Mariana Trench. Interspersed with the islands are many strange underwater volcanoes.

For example, the underwater volcano Eifuku erupts liquid carbon dioxide from hydrothermal chimney-like vents. The fluid coming out of these pipes is 217 degrees Fahrenheit (103 degrees Celsius). At the underwater volcano Daikoku, scientists have discovered a pool of molten sulfur 410 meters below the surface of the ocean, which does not exist anywhere else on Earth.

Life and inhabitants in the Mariana Trench

Recent scientific expeditions found surprisingly diverse life in these harsh environments. Animals living in the deepest parts of the Mariana Trench survive in total darkness and extreme pressure, said Natasha Gallo of the Scripps Institution of Oceanography, who studied footage from Cameron's 2012 expedition.

Food in the Mariana Trench is extremely limited, since the deep gorge is far from land. Leaves, coconuts and trees rarely make it to the bottom of the trench, Gallo said, and dead plankton sinking from the surface must fall thousands of meters to reach Challenger Deep. Instead, some microbes rely on chemicals like methane or sulfur, while other creatures devour marine life further down the food chain.

The three most common organisms at the bottom of the Mariana Trench are xenophyophores, amphipods, and small sea ​​cucumbers(holothurians).

Single-celled xenophyophores resemble giant amoebas. Amphipods are shiny, shrimp-like scavengers commonly found in deep sea trenches. Holothurians may be a new species of bizarre, translucent sea cucumber.

"These are some of the deepest holothurians ever observed and were relatively numerous," Gallo said.

The scientists also identified more than 200 different microorganisms in the mud collected from the Challenger Deep. The mud was transported to the laboratory on land in special canisters, and is carefully stored under conditions that replicate the temperature and pressure at the bottom.

During the Cameron expedition in 2012, scientists also found bacterial mats in the Sirena Depth Basin, located in the area east of the Challenger Depth. These clusters of microbes feed on the hydrogen and methane released chemical reactions between sea ​​water and breeds.

In 2017, scientists reported that they had collected samples of an unusual creature dubbed Mariana snailfish, which lives at a depth of about 8,000 m. The snail's small, pink, and scaleless body is unlikely to survive in such an aggressive environment, but this fish is full of surprises, researchers report. The animal appears to dominate this ecosystem, diving deeper than any other fish and taking advantage of the lack of competition to devour the invertebrates abundantly inhabiting the trench.

Pollution in the deep

Unfortunately, the deep ocean acts as a potential sink for discarded pollutants and debris. In a recent study, a team of scientists from Newcastle University showed that man-made chemicals that were banned in the 1970s are still lurking in the deepest parts of the ocean.

During sampling of amphipods (shrimps, crustaceans), the researchers found extremely high levels persistent organic pollutants (POPs) in the adipose tissue of organisms. These include polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs), chemicals commonly used as electrical insulators and flame retardants, according to a study published in the journal Nature Ecology & Evolution. These POPs were released into the environment as a result of industrial accidents and spills in landfills from the 1930s until the 1970s, when they were finally banned.

“We still think of the deep ocean as this remote and untouched realm, protected from human impact, but our research shows that unfortunately this is not true,” said Alan Jamieson of the University of Newcastle.

In fact, the amphipods in the study contained levels of contamination similar to those found in Suruga Bay, one of the most polluted industrial areas in the Pacific Northwest.

Since POPs cannot be destroyed naturally, they are stored in environment for decades, reaching the ocean floor as a result of pollution from plastic debris and dead animals. The pollutants are then carried from creature to creature through the ocean food chain, eventually resulting in chemical concentrations much higher than surface level pollution.

"The fact that we have found these pollutants in one of the most remote and inaccessible habitats on earth truly proves the devastating impact that humanity is having on the planet," Jamison said in a press release.

The researchers say the next step is to understand the effects of this pollution and what it does to the ecosystem as a whole.

The Mariana Trench is considered the deepest place on earth's surface . Since the ocean, compared to land, has not been studied well enough, this zone hides a lot mystical riddles. And the monsters living in it are a favorite topic for discussion and reasoning.

Location of the Mariana Trench

The Mariana Trench is a crescent-shaped trench. It is located in the Pacific Ocean. Own The basin was named after the nearby Mariana Islands.. The length is about 2550 km, and the width is about 70 km.

However, the ocean diligently hides its real parameters. It is known that it has a V-shape. One of the main puzzles is its depth. Modern appliances show a mark of 10994 m with an error of 40 km.

Attention! The deepest mark is called the "Challenger Abyss" and is located 340 km from the island of Guam.

Chute diving

The study of the place is carried out with the help of deep-sea vehicles. So, in 1960, Jacques Picard and Don Walsh went down to the bottom on the Trieste bathyscaphe. For 8 hours, the installation rose back to the surface. After inspection, damage to the skin and lifting cables was found.

Submersions of vehicles were made in 1995 by the Japanese, also in 1996. Americans. The steel structure was dented by sea monsters.

Later, the German bathyscaphe "Highfish" with three researchers on board sank already 7 km. At the same time, scientists have recorded the appearance of strange creatures.

Important! Thanks to hydrothermal springs, general temperature water in the abyss warms up to +4 degrees.

The Daikoku volcano was recorded in the Mariana Trench, where the crater is 187 degrees. Its analogue is found only on the satellite of Jupiter (Io).

History of transparent fish

In 1948, lobster hunters from Australia told unusual story about a transparent fish. Its length is at least 30 m. According to the stories of fishermen, outwardly it is very similar to a shark that lived in ancient times.

The monster had a mouth about two meters. Teeth up to 10 cm in size have been found on the ocean floor. This gave rise to speculation that, perhaps, terrible predators live at a depth.

Encounter with monsters

Scientists are still not able to identify objects living at the very bottom of the gutter. During the dive, many photographs were taken showing strange and frightening creatures.

it one and a half meter worms without a mouth, mutated octopuses and giant starfish.

Toxins and radiation

British experts published an interesting document, according to which body marine life soaked through with toxic substances.

They recorded a level of pollution much higher than that which was filmed from animals living in coastal waters. Furthermore, some species even emitted radiation.

Reference! The bottom of the cavity is covered with mucus. Here, mainly, particles of shells and ancient plankton. Due to the pressure of the water, everything turns into fine thick mud.

Prehistoric megalodons are alive

Assumed scientific world one of giant sharks prehistoric period - megalodon disappeared millions of years ago. In 1997, Japanese experts made a frightening video. They designed a feeder to which they lured a creature a couple of tens of meters long. This proved the fact that megalodons are still alive.

Various sea animals

Important! On May 31, 2009, the Nereus apparatus was submerged, it measured the depth of the depression - 10,902 m below sea level. Were received unique photos inhabitants of the depths.

The gutter has become a habitat massive unicellular amoeba. Their sizes reach up to 10 cm. Moreover, they can easily exist next to uranium, lead and mercury. And from such a neighborhood, they only feel better. Everything living and non-living is brought together here.

The Mariana Trench is fraught with many secrets that are not subject to full study even with modern equipment. Paradoxically, even at such an impressive depth, life has been discovered.

While thousands of people have visited the highest point on the planet, Everest, only three have 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 that is unknown. Hitech talks about geological structure the lowest point of the planet and about the strange processes that occur at its bottom.

Without sunlight and under colossal pressure

The Mariana Trench is not a vertical abyss. It is a crescent-shaped trough that stretches 2,500 km east of the Philippines and west of Guam, USA. The deepest point of the basin, the Challenger Deep, is located at a distance of 11 km from the surface of the Pacific Ocean. Everest, if it were at the bottom of the depression, 2.1 km would not be enough to 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 load 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 set the current depth to 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. The temperature is only a few degrees above zero - and close to the freezing point. The pressure in the abyss of the Challenger is 108.6 MPa, which is about 1,072 times greater than normal atmospheric pressure at the level of the oceans. This is five times the pressure that is created when a bullet hits a bulletproof object and is approximately equal to the pressure inside a reactor for the synthesis of polyethylene. But people have found a way to get to the bottom.

man in the deep

The first people to visit the Challenger abyss were the US military Jacques Piccard and Don Walsh. In 1960, on the Trieste bathyscaphe, they descended 10,918 m in five hours. At this point, the researchers spent 20 minutes and saw almost nothing because of the silt clouds raised by the apparatus. Except for the fish from the flounder species, which was hit by a searchlight beam. The presence of life under such high pressure became 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 the bones of vertebrates must literally dissolve. No bones, no fish. But nature has shown scientists that they are wrong: living organisms are able to adapt even to such unbearable conditions.

A lot of living organisms in the abyss of the Challenger were discovered by the Deepsea Challenger bathyscaphe, on which director James Cameron alone descended 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 shrimps and crabs.

At a depth of 8 thousand meters, the bathyscaphe discovered the most deep sea fish- a new representative of the species of lipar or sea slugs. The head of the fish resembles that of a dog, and its body is very thin and elastic - while moving, it resembles a translucent napkin that is carried by the current.

A few hundred meters below live giant ten-centimeter amoeba called xenophyophores. These organisms show amazing resistance to several elements and chemicals, such as mercury, uranium, and lead, which would kill other animals or humans in minutes.

Scientists believe that there are many more species at depth 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 a breakthrough in biomedicine and biotechnology and will help to understand how life began on Earth. For example, researchers from the University of Hawaii believe that thermal mud volcanoes near the basin could provide conditions for the survival of the first organisms on the planet.

Volcanoes at the bottom of the Mariana Trench.

What's the break?

The depression owes its depth to the fault of two tectonic plates - the Pacific layer goes under the Philippine, forming a deep trench. The regions in which such geological events have occurred are called the subduction zone.

The thickness of each plate is almost 100 km, and the depth of the fault is at least 700 km from the lowest point of the Challenger Deep. “This is an iceberg. The man wasn't even at the top - 11 was nothing compared to the 700 lurking in the depths. The Mariana Trench is the boundary between the limits of human knowledge and a reality that is inaccessible to man,” 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 - the rocks at the fault boundaries act like sponges, absorbing water and transporting it into the bowels of the planet. As a result, the substance is at a depth of 20 to 100 km below the seabed.

Geologists from the University of Washington have found that over the past million years, more than 79 million tons of water have entered the bowels of the earth through the junction - this is 4.3 times more than previous estimates.

The main question is what happens to the water in the bowels. Volcanoes are thought to complete the water cycle by returning water to the atmosphere as water vapor during eruptions. This theory was supported by previous measurements of the volume of water penetrating into the mantle. Volcanoes ejected into the atmosphere approximately equal to the absorbed volume.

A new study refutes this theory - calculations suggest that the Earth absorbs more water than returns. And this is really strange - provided that the level of the World Ocean over the past few hundred years has not only not decreased, but also increased by several centimeters.

A possible solution is to abandon the theory of equal capacity of all subduction zones on Earth. It is likely that the conditions in the Mariana Trench are more extreme than in other parts of the planet, and more water enters the bowels through a rift in the Challenger Deep.

“Does the amount of water depend on the structural features of the subduction zone, for example, on the angle of the bend of the plates? We assume that similar faults exist in Alaska and in Latin America, but so far, humans have not been able to detect a deeper structure than the Mariana Trench,” added study lead author Doug Vines.

Water hiding in the bowels of the Earth is not the only mystery of the Mariana Trench. National Administration oceanic and atmospheric research The US (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 by several underwater 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. Geothermal springs are located 6 km below, throwing water at a temperature of 450 ° C. But this water does not boil - the process is hindered by the pressure exerted by a 6.5-kilometer water column.

The ocean floor has been less explored by man today than the moon. Probably, scientists will be able to detect faults deeper than the Mariana Trench, or at least explore its structure and features.

Mariana Trench- the deepest place on our planet. This absolute depth got its name thanks to the nearby Mariana Islands. The entire depression stretched along the islands for one and a half thousand kilometers and has a characteristic V-shaped profile. In fact, this is an ordinary tectonic fault, the place where the Pacific plate comes under the Philippine, just the Mariana Trench - this is the deepest place of this kind. Its slopes are steep, about 7–9° on average, and the bottom is flat, 1 to 5 kilometers wide, and divided by rapids into several closed sections. The pressure at the bottom of the Mariana Trench reaches 108.6 MPa - this is more than 1100 times more than normal atmospheric pressure!

The first who dared to challenge the abyss were the British - the military three-masted corvette "Challenger" with sailing equipment was rebuilt into an oceanographic vessel for hydrological, geological, chemical, biological and meteorological work back in 1872. But the first data on the depth of the Mariana Trench were obtained only in 1951 - according to the measurements, the depth of the trench was declared equal to 10,863 m. After that, the deepest point of the Mariana Trench was called the “Challenger Deep”. It is hard to imagine that the highest mountain of our planet, Everest, can easily fit in the depths of the Mariana Trench, and more than a kilometer of water will remain above it to the surface.

Next explorers of the Mariana Trench there were already Soviet scientists - in 1957, during the 25th voyage of the Soviet research vessel Vityaz, they not only announced maximum depth depression equal to 11,022 meters, but also established the existence of life at depths of more than 7000 meters, thereby refuting the then prevailing idea of ​​the impossibility of life at depths of more than 6000-7000 meters.

On January 23, 1960, the first human dive to the bottom of the Mariana Trench was carried out. This dive was made by US Navy Lieutenant Don Walsh and explorer Jacques Picard.

During the dive, they were protected by armored, 127 millimeter thick, walls of a bathyscaphe called Trieste. Bathyscaphe was named after the Italian city of Trieste, in which the main work on its creation was carried out. According to the instruments aboard the Trieste, Walsh and Picard sank to a depth of 11,521 meters, but later this figure was slightly corrected - 10,918 meters.

The dive took about five, and the ascent took about three hours, the researchers spent only 12 minutes at the bottom. But even this time was enough for them to make sensational discovery- at the bottom they found flat fish up to 30 cm in size, similar to flounder.

Studies in 1995 showed that the depth of the Mariana Trench is about 10,920 m, and the Japanese Kaik probe, launched into the Challenger Deep on March 24, 1997, recorded a depth of 10,911.4 meters.

Mariana Trench more than once frightened researchers with monsters lurking in its depths. For the first time, the expedition of the American research vessel Glomar Challenger encountered the unknown. Some time after the start of the descent of the apparatus, the sound-recording device began to transmit some kind of metallic rattle to the surface, reminiscent of the sound of sawn metal. At this time, some indistinct shadows appeared on the monitor, similar to giant fairy-tale dragons with several heads and tails. An hour later, scientists became worried that the unique equipment, made in the NASA laboratory from beams of ultra-strong titanium-cobalt steel, having a spherical structure, the so-called "hedgehog" with a diameter of about 9 m, could remain in the abyss of the Mariana Trench forever - so it was decided to immediately raise apparatus on board the ship. The “Hedgehog” was retrieved from the depths for more than eight hours, and as soon as it appeared on the surface, they immediately put it on a special raft. The TV camera and echo sounder were raised on the deck of the Glomar Challenger. The researchers were horrified when they saw how the strongest steel beams of the structure were deformed, as for the 20-cm steel cable on which the “hedgehog” was lowered, the scientists were not mistaken in the nature of the sounds transmitted from the abyss of water - the cable was half sawn. Who tried to leave the device at depth and why - so forever will remain a mystery. Details of this incident were published in 1996 by the New York Times.

Another collision with the inexplicable in the depths of the Mariana Trench occurred with the German research apparatus "Highfish" with a crew on board. At a depth of 7 km, the device suddenly stopped moving. To find out the cause of the malfunction, 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, biting its teeth into a bathyscaphe, tried to crack it like a nut. Recovering from the shock, the crew activated a device called an "electric gun", and the monster, struck by a powerful discharge, disappeared into the abyss.

May 31, 2009 on floor of the Mariana Trench plunged automatic submersible Nereus. According to measurements, he sank 10,902 meters below sea level. At the bottom, Nereus filmed a video, took some photos, and even collected sediment samples from the bottom. Thanks to modern technologies, the researchers managed to capture a few representatives of the Mariana Trench.

In 2012, American director James Cameron descended on the Deepsea Challenger bathyscaphe to the bottom of the Mariana Trench. He reached a depth of 10,898 m.