Ways to dive into the ocean. Deep sea exploration

There are many more places on earth about which we know less than about the vast expanses of space. We are talking primarily about unconquerable water depths. According to scientists, science has not yet actually begun to study the mysterious life at the bottom of the oceans; all research is at the beginning of the journey.

From year to year there are more and more daredevils who are ready to perform a new record-breaking deep-sea dive. In the presented material I would like to talk about swims without equipment, with scuba gear and with the help of bathyscaphes, which have gone down in history.

Deepest human dive

For a long time, the French athlete Loïc Leferme held the record for freediving. In 2002, he managed to make a deep-sea dive to 162 meters. Many divers tried to improve this indicator, but died in the depths of the sea. In 2004, Leferm himself became a victim of his own vanity. During a training swim in the oceanic trench of Villefranche-sur-Mer, he dived to 171 meters. However, the athlete failed to rise to the surface.

The latest record-breaking deep-sea dive was made by Austrian freediver Herbert Nitzsch. He managed to descend to 214 meters without an oxygen tank. Thus, the achievement of Loïc Leferme is a thing of the past.

Record deep-sea dive for women

French athlete Audrey Mestre set several records among women. On May 29, 1997, she dived as much as 80 meters on a single breath-hold, without an air tank. A year later, Audrey broke her own record, descending 115 meters into the depths of the sea. In 2001, the athlete dived as much as 130 meters. This record, which has world status among women, is assigned to Audrey to this day.

On October 12, 2002, Mestre made her last attempt in life, diving without equipment to 171 meters off the coast of the Dominican Republic. The athlete used only a special load, without oxygen cylinders. The lift was to be carried out using an air dome. However, the latter turned out to be unfilled. 8 minutes after the deep-sea dive started, Audrey's body was brought to the surface by scuba divers. The official cause of death of the athlete was noted as problems with the equipment for lifting to the surface.

Record scuba dive

Now let's talk about deep-sea scuba diving. The most significant of them was carried out by the French diver Pascal Bernabe. In the summer of 2005, he managed to descend 330 meters into the depths of the sea. Although it was initially planned to conquer a depth of 320 meters. Such a significant record was achieved as a result of a small incident. During the descent, Pascal's rope stretched, which allowed him to swim an extra 10 meters in depth.

The diver managed to successfully rise to the surface. The ascent lasted a long 9 hours. The reason for such a slow rise was the high risk of development, which could lead to respiratory arrest and damage to blood vessels. It is worth noting that to set the record, Pascal Bernabe had to spend 3 whole years in constant training.

Record dive in a submersible

On January 23, 1960, scientists Donald Walsh and Jacques Piccard set a record for diving to the bottom of the ocean in a manned vehicle. While aboard the small submarine Trieste, the researchers reached the bottom at a depth of 10,898 meters.

The deepest dive in a manned submersible was achieved thanks to the construction of the Deepsea Challenger, which took the designers 8 long years. This mini-submarine is a streamlined capsule weighing more than 10 tons and with a wall thickness of 6.4 cm. It is noteworthy that before being put into operation, the bathyscaphe was tested several times with a pressure of 1160 atmospheres, which is higher than the pressure that was supposed to affect the walls of the device on the ocean floor .

In 2012, the famous American film director James Cameron, piloting the mini-submarine Deepsea Challenger, conquered the previous record set by the Trieste device, and even improved it by plunging 11 km into the Mariinsky Trench.

We live on a planet of water, but we know the Earth's oceans less well than some cosmic bodies. More than half of the surface of Mars has been mapped with a resolution of about 20 m - and only 10-15% of the ocean floor has been studied with a resolution of at least 100 m. 12 people have been on the Moon, three have been to the bottom of the Mariana Trench, and all of them did not dare to stick their nose out of the heavy-duty bathyscaphes.

Let's dive in

The main difficulty in the development of the World Ocean is pressure: for every 10 m of depth it increases by another atmosphere. When the count reaches thousands of meters and hundreds of atmospheres, everything changes. Liquids flow differently, gases behave unusually... Devices capable of withstanding these conditions remain piecemeal products, and even the most modern submarines are not designed for such pressure. The maximum diving depth of the latest Project 955 Borei nuclear submarines is only 480 m.

Divers descending hundreds of meters are respectfully called aquanauts, comparing them with space explorers. But the abyss of the seas is in its own way more dangerous than the vacuum of space. If something happens, the crew working on the ISS will be able to transfer to the docked ship and in a few hours will be on the surface of the Earth. This route is closed to divers: it may take weeks to evacuate from the depths. And this period cannot be shortened under any circumstances.

However, there is an alternative route to depth. Instead of creating ever more durable hulls, you can send there... living divers. The record of pressure endured by testers in the laboratory is almost double the capabilities of submarines. There is nothing incredible here: the cells of all living organisms are filled with the same water, which freely transmits pressure in all directions.

The cells do not resist the water column, like the solid hulls of submarines; they compensate for external pressure with internal ones. It is not for nothing that the inhabitants of “black smokers”, including roundworms and shrimp, feel great at many kilometers deep in the ocean floor. Some types of bacteria can withstand even thousands of atmospheres quite well. Man is no exception here - the only difference is that he needs air.

Beneath the surface

Oxygen Breathing tubes made of reeds were known to the Mohicans of Fenimore Cooper. Today, hollow plant stems have been replaced by plastic tubes, “anatomically shaped” and with comfortable mouthpieces. However, this did not make them more effective: the laws of physics and biology interfere.

Already at a meter depth, the pressure on the chest rises to 1.1 atm - 0.1 atm of water column is added to the air itself. Breathing here requires a noticeable effort of the intercostal muscles, and only trained athletes can cope with this. At the same time, even their strength will not last long and at a maximum of 4-5 m depth, and beginners have difficulty breathing even at half a meter. In addition, the longer the tube, the more air it contains. The “working” tidal volume of the lungs is on average 500 ml, and after each exhalation, part of the exhaust air remains in the tube. Each breath brings less oxygen and more carbon dioxide.

Forced ventilation is required to deliver fresh air. By pumping gas under increased pressure, you can ease the work of the chest muscles. This approach has been used for more than a century. Hand pumps have been known to divers since the 17th century, and in the middle of the 19th century, English builders who erected underwater foundations for bridge supports already worked for a long time in an atmosphere of compressed air. For the work, thick-walled, open-bottom underwater chambers were used, in which high pressure was maintained. That is, caissons.

Deeper than 10 m

Nitrogen No problems arose during work in the caissons themselves. But upon returning to the surface, construction workers often developed symptoms that French physiologists Paul and Vattel described in 1854 as On ne paie qu'en sortant - "payback at the exit." It could be severe itching of the skin or dizziness, pain in the joints and muscles. In the most severe cases, paralysis developed, loss of consciousness occurred, and then death.

To go to the depths without any difficulties associated with extreme pressure, you can use heavy-duty spacesuits. These are extremely complex systems that can withstand immersion of hundreds of meters and maintain a comfortable pressure of 1 atm inside. True, they are very expensive: for example, the price of a recently introduced spacesuit from the Canadian company Nuytco Research Ltd. EXOSUIT is about a million dollars.

The problem is that the amount of gas dissolved in a liquid directly depends on the pressure above it. This also applies to air, which contains about 21% oxygen and 78% nitrogen (other gases - carbon dioxide, neon, helium, methane, hydrogen, etc. - can be neglected: their content does not exceed 1%). If oxygen is quickly absorbed, then nitrogen simply saturates the blood and other tissues: with an increase in pressure by 1 atm, an additional 1 liter of nitrogen dissolves in the body.

With a rapid decrease in pressure, excess gas begins to be released rapidly, sometimes foaming, like an opened bottle of champagne. The resulting bubbles can physically deform tissues, block blood vessels and deprive them of blood supply, leading to a wide variety of and often severe symptoms. Fortunately, physiologists figured out this mechanism quite quickly, and already in the 1890s, decompression sickness could be prevented by using a gradual and careful decrease in pressure to normal - so that nitrogen leaves the body gradually, and blood and other fluids do not “boil” .

At the beginning of the twentieth century, English researcher John Haldane compiled detailed tables with recommendations on the optimal modes of descent and ascent, compression and decompression. Through experiments with animals and then with people - including himself and his loved ones - Haldane found that the maximum safe depth without requiring decompression was about 10 m, and even less for a long dive. Returning from the depths should be done gradually and slowly to give the nitrogen time to be released, but it is better to descend rather quickly, reducing the time for excess gas to enter the body tissues. New limits of depth were revealed to people.

Deeper than 40 m

Helium The fight against depth is like an arms race. Having found a way to overcome the next obstacle, people took a few more steps - and met a new obstacle. So, after decompression sickness, a scourge appeared, which divers almost lovingly call “nitrogen squirrel”. The fact is that under hyperbaric conditions this inert gas begins to act no worse than strong alcohol. In the 1940s, the intoxicating effect of nitrogen was studied by another John Haldane, the son of “the one.” His father’s dangerous experiments did not bother him at all, and he continued harsh experiments on himself and his colleagues. “One of our subjects suffered a lung rupture,” the scientist wrote in the journal, “but he is now recovering.”

Despite all the research, the mechanism of nitrogen intoxication has not been established in detail - however, the same can be said about the effect of ordinary alcohol. Both disrupt normal signal transmission at the synapses of nerve cells, and perhaps even change the permeability of cell membranes, turning ion exchange processes on the surfaces of neurons into complete chaos. Outwardly, both manifest themselves in similar ways. A diver who “caught a nitrogen squirrel” loses control of himself. He may panic and cut the hoses, or, conversely, get carried away by telling jokes to a school of cheerful sharks.

Other inert gases also have a narcotic effect, and the heavier their molecules, the less pressure is required for this effect to manifest itself. For example, xenon anesthetizes under normal conditions, but lighter argon only anesthetizes under several atmospheres. However, these manifestations are deeply individual, and some people, when diving, feel nitrogen intoxication much earlier than others.

You can get rid of the anesthetic effect of nitrogen by reducing its intake into the body. This is how nitrox breathing mixtures work, containing an increased (sometimes up to 36%) proportion of oxygen and, accordingly, a reduced amount of nitrogen. It would be even more tempting to switch to pure oxygen. After all, this would make it possible to quadruple the volume of breathing cylinders or quadruple the time of working with them. However, oxygen is an active element, and with prolonged inhalation it is toxic, especially under pressure.

Pure oxygen causes intoxication and euphoria, and leads to membrane damage in the cells of the respiratory tract. At the same time, the lack of free (reduced) hemoglobin makes it difficult to remove carbon dioxide, leads to hypercapnia and metabolic acidosis, triggering physiological reactions of hypoxia. A person suffocates, despite the fact that his body has enough oxygen. As the same Haldane Jr. established, even at a pressure of 7 atm, you can breathe pure oxygen for no longer than a few minutes, after which breathing disorders, convulsions begin - everything that in diving slang is called the short word “blackout”.

Liquid breathing

The still semi-fantastic approach to conquering depth is to use substances that can take over the delivery of gases instead of air - for example, the blood plasma substitute perftoran. In theory, the lungs can be filled with this bluish liquid and, saturating it with oxygen, pump it through pumps, providing breathing without any gas mixture at all. However, this method remains deeply experimental; many experts consider it a dead end, and, for example, in the USA the use of perftoran is officially prohibited.

Therefore, the partial pressure of oxygen when breathing at depth is maintained even lower than usual, and nitrogen is replaced with a safe and non-euphoric gas. Light hydrogen would be better suited than others, if not for its explosiveness when mixed with oxygen. As a result, hydrogen is rarely used, and the second lightest gas, helium, has become a common substitute for nitrogen in the mixture. On its basis, oxygen-helium or oxygen-helium-nitrogen breathing mixtures are produced - helioxes and trimixes.

Deeper than 80 m

Complex mixtures It is worth saying here that compression and decompression at pressures of tens and hundreds of atmospheres takes a long time. So much so that it makes the work of industrial divers - for example, when servicing offshore oil platforms - ineffective. The time spent at depth becomes much shorter than long descents and ascents. Already half an hour at 60 m results in more than an hour of decompression. After half an hour at 160 m, it will take more than 25 hours to return - and yet divers have to go lower.

Therefore, deep-sea pressure chambers have been used for these purposes for several decades. People sometimes live in them for whole weeks, working in shifts and making excursions outside through the airlock compartment: the pressure of the respiratory mixture in the “dwelling” is maintained equal to the pressure of the aquatic environment around. And although decompression when ascending from 100 m takes about four days, and from 300 m - more than a week, a decent period of work at depth makes these losses of time completely justified.

Methods for prolonged exposure to high-pressure environments have been developed since the mid-twentieth century. Large hyperbaric complexes made it possible to create the required pressure in laboratory conditions, and the brave testers of that time set one record after another, gradually moving to the sea. In 1962, Robert Stenuis spent 26 hours at a depth of 61 m, becoming the first aquanaut, and three years later, six Frenchmen, breathing trimix, lived at a depth of 100 m for almost three weeks.

Here, new problems began to arise associated with people's long stay in isolation and in a debilitatingly uncomfortable environment. Due to the high thermal conductivity of helium, divers lose heat with each exhalation of the gas mixture, and in their “home” they have to maintain a consistently hot atmosphere - about 30 ° C, and the water creates high humidity. In addition, the low density of helium changes the timbre of the voice, seriously complicating communication. But even all these difficulties taken together would not put a limit to our adventures in the hyperbaric world. There are more important restrictions.

Below 600 m

Limit In laboratory experiments, individual neurons growing “in vitro” do not tolerate extremely high pressure well, demonstrating erratic hyperexcitability. It seems that this significantly changes the properties of cell membrane lipids, so that these effects cannot be resisted. The result can also be observed in the human nervous system under enormous pressure. He begins to “switch off” every now and then, falling into short periods of sleep or stupor. Perception becomes difficult, the body is seized with tremors, panic begins: high-pressure nervous syndrome (HBP) develops, caused by the very physiology of neurons.

In addition to the lungs, there are other cavities in the body that contain air. But they communicate with the environment through very thin channels, and the pressure in them does not equalize instantly. For example, the middle ear cavities are connected to the nasopharynx only by a narrow Eustachian tube, which is also often clogged with mucus. The associated inconveniences are familiar to many airplane passengers who have to tightly close their nose and mouth and exhale sharply, equalizing the pressure of the ear and the external environment. Divers also use this kind of “blowing”, and when they have a runny nose they try not to dive at all.

Adding small (up to 9%) amounts of nitrogen to the oxygen-helium mixture allows these effects to be somewhat weakened. Therefore, record dives on heliox reach 200-250 m, and on nitrogen-containing trimix - about 450 m in the open sea and 600 m in a compression chamber. The French aquanauts became - and still remain - the legislators in this area. Alternating air, complex breathing mixtures, tricky diving and decompression modes back in the 1970s allowed divers to overcome the 700 m depth bar, and the COMEX company, created by students of Jacques Cousteau, made the world leader in diving maintenance of offshore oil platforms. The details of these operations remain a military and commercial secret, so researchers from other countries are trying to catch up with the French, moving in their own ways.

Trying to go deeper, Soviet physiologists studied the possibility of replacing helium with heavier gases, such as neon. Experiments to simulate a dive to 400 m in an oxygen-neon atmosphere were carried out in the hyperbaric complex of the Moscow Institute of Medical and Biological Problems (IMBP) of the Russian Academy of Sciences and in the secret “underwater” Research Institute-40 of the Ministry of Defense, as well as in the Research Institute of Oceanology named after. Shirshova. However, the heaviness of neon showed its downside.

It can be calculated that already at a pressure of 35 atm the density of the oxygen-neon mixture is equal to the density of the oxygen-helium mixture at approximately 150 atm. And then - more: our airways are simply not suitable for “pumping” such a thick environment. IBMP testers reported that when the lungs and bronchi work with such a dense mixture, a strange and heavy feeling arises, “as if you are not breathing, but drinking air.” While awake, experienced divers are still able to cope with this, but during periods of sleep - and it is impossible to reach such a depth without spending long days descending and ascending - they are constantly awakened by a panicky sensation of suffocation. And although the military aquanauts from NII-40 managed to reach the 450-meter bar and receive well-deserved medals of Heroes of the Soviet Union, this did not fundamentally solve the issue.

New diving records may still be set, but we have apparently reached the final frontier. The unbearable density of the respiratory mixture, on the one hand, and the nervous syndrome of high pressure, on the other, apparently put the final limit on human travel under extreme pressure.

Ocean research.

21. From the history of the conquest of the deep sea.

© Vladimir Kalanov,
"Knowledge is power".

It is impossible to study the World Ocean without diving into its depths. The study of the surface of the oceans, their size and configuration, surface currents, islands and straits has been going on for many centuries and has always been an extremely difficult and dangerous task. Studying the ocean depths presents no less difficulties, and some difficulties remain insurmountable to this day.

Man, having first dived under water in ancient times, of course, did not pursue the goal of studying the depths of the sea. Surely his tasks were then purely practical, or, as they say now, pragmatic, for example: to get a sponge or shellfish from the bottom of the sea for food.

And when beautiful balls of pearls were found in the shells, the diver brought them to his hut and gave them to his wife as decoration, or took them for himself for the same purpose. Only people who lived on the shores of warm seas could dive into the water and become divers. They didn't risk catching a cold or getting muscle cramps underwater.

The ancient diver, taking a knife and a net to collect prey, clutched a stone between his legs and threw himself into the abyss. This assumption is quite easy to make, because pearl fishers in the Red and Arabian Seas, or professional divers from the Indian Parawa tribe still do just that. They don't know either scuba gear or masks. All their equipment remained exactly the same as it was a hundred or a thousand years ago.

But a diver is not a diver. A diver uses underwater only what nature has given him, and a diver uses special devices and equipment in order to dive deeper into the water and stay there longer. A diver, even a well-trained one, cannot stay underwater for more than one and a half minutes. The maximum depth to which it can dive does not exceed 25-30 meters. Only a few record holders are able to hold their breath for 3-4 minutes and dive somewhat deeper.

If you use such a simple device as a breathing tube, you can stay under water for quite a long time. But what is the point of this if the immersion depth cannot be more than one meter? The fact is that at greater depths it is difficult to inhale through a tube: greater strength of the chest muscles is needed to overcome the pressure of the breath acting on the human body, while the lungs are under normal atmospheric pressure.

Already in ancient times, attempts were made to use primitive devices for breathing at shallow depths. For example, with the help of weights, some kind of bell-type vessel turned upside down was lowered to the bottom, and the diver could use the air supply in this vessel. But it was possible to breathe in such a bell only for a few minutes, since the air was quickly saturated with exhaled carbon dioxide and became unsuitable for breathing.

As man began to explore the ocean, problems arose with the invention and manufacture of the necessary diving devices not only for breathing, but also for vision in water. A person with normal vision, opening his eyes in water, sees surrounding objects very faintly, as if in a fog. This is explained by the fact that the refractive index of water is almost equal to the refractive index of the eye itself. Therefore, the lens cannot focus the image on the retina, and the focus of the image is far behind the retina. It turns out that a person in water becomes extremely farsighted - up to plus 20 diopters and more. In addition, direct contact with sea and even fresh water causes eye irritation and pain.

Even before the invention of underwater goggles and masks with glass, divers of past centuries strengthened plates in front of their eyes, sealing them with a piece of cloth soaked in resin. The plates were made from the thinnest polished sections of horn and had a certain transparency. Without such devices, it was impossible to carry out many works during the construction of ports, deepening harbors, finding and raising sunken ships, cargo, and so on.

In Russia, during the era of Peter I, when the country reached the sea coast, diving acquired practical importance.

Rus' has always been famous for its craftsmen, a generalized portrait of whom was created by the writer Ershov in the image of Lefty, who shod an English flea. One of these craftsmen went down in the history of technology under Peter I. It was Efim Nikonov, a peasant from the village of Pokrovskoye near Moscow, who in 1719 made a wooden submarine (“hidden vessel”), and also proposed the design of a leather diving suit with a barrel for air, which was worn on the head and had windows for the eyes. But he was unable to bring the design of the diving suit to the required working condition, since his “hidden vessel” did not withstand the test and sank in the lake, as a result of which E. Nikonov was denied funds. The inventor, of course, could not have known that in his diving suit with a barrel of air on his head, a person in any case would not be able to hold out for more than 2-3 minutes.

The problem of breathing underwater with the supply of fresh air to the diver could not be solved for several centuries. In the Middle Ages and even later, inventors had no idea about the physiology of respiration and gas exchange in the lungs. Here is one example that borders on the curious. In 1774, the French inventor Fremins proposed a design for working underwater, consisting of a helmet connected by copper tubes to a small air tank. The inventor believed that the difference between inhaled and exhaled air was only the difference in temperature. He hoped that the exhaled air, passing under water through the tubes, would cool and become breathable again. And when, during testing of this device, the diver began to choke after two minutes, the inventor was terribly surprised.

When it became clear that for a person to work underwater, fresh air must be continuously supplied, they began to think about ways to supply it. At first they tried to use bellows like blacksmith's for this purpose. But this method failed to supply air to a depth of more than one meter - the bellows did not create the necessary pressure.

Only at the beginning of the 19th century was a pressure air pump invented, which provided the diver with air to a significant depth.

For a century, the air pump was driven by hand, then mechanical pumps appeared.

The first diving suits had helmets that were open at the bottom, into which air was pumped through a hose. The exhaled air came out through the open edge of the helmet. A diver in such a suit, so to speak, could only work in a vertical position, because even a slight tilt of the submariner led to the filling of the helmet with water. The inventors of these first diving suits were, independently of each other, the Englishman A. Siebe (1819) and the Kronstadt mechanic Gausen (in 1829). Soon they began to produce improved diving suits, in which the helmet was hermetically connected to the jacket, and the exhaled air was released from the helmet with a special valve.

But the improved version of the diving suit did not provide the diver with complete freedom of movement. The heavy air hose interfered with work and limited the range of movement. Although this hose was vital for the submariner, it was often the cause of his death. This happened when the hose was pinched by some heavy object or damaged with an air leak.

The task of developing and manufacturing diving equipment in which the submariner would not be dependent on air supply from an external source and would be completely free in his movements arose with all clarity and necessity.

Many inventors took up the challenge of designing such autonomous equipment. More than a hundred years have passed since the manufacture of the first diving suits, and only in the middle of the 20th century a device appeared that became known as scuba. The main part of the scuba gear is the breathing apparatus, which was invented by the famous French explorer of the ocean depths, later the world famous scientist Jacques-Yves Cousteau and his colleague Emile Gagnan. At the height of the Second World War, in 1943, Jacques-Yves Cousteau and his friends Philippe Taillet and Frederic Dumas first tested a new device for immersion in water. Scuba (from the Latin aqua - water and English lung - lung) is a backpack apparatus consisting of compressed air cylinders and a breathing apparatus. Tests have shown that the device works accurately, the diver easily, effortlessly inhales clean, fresh air from a steel cylinder. The scuba diver dives and ascends freely, without feeling any inconvenience.

During operation, the scuba gear was structurally modified, but in general its structure remained unchanged. However, no design changes will give the scuba tank the ability to dive deeply. A scuba diver, like a diver in a soft diving suit receiving air through a hose, cannot cross the hundred-meter depth barrier without risking his life. The main obstacle here remains the problem of breathing.

The air that all people on the surface of the Earth breathe, when a diver dives to 40–60 meters, causes poisoning similar to alcohol intoxication. Having reached the specified depth, the submariner suddenly loses control over his actions, which often ends tragically. It has been established that the main reason for such “deep intoxication” is the effect of nitrogen under high pressure on the nervous system. Nitrogen in scuba cylinders was replaced with inert helium, and “deep intoxication” stopped occurring, but another problem appeared. The human body is very sensitive to the percentage of oxygen in the inhaled mixture. At normal atmospheric pressure, the air a person breathes should contain about 21 percent oxygen. With such an oxygen content in the air, man has gone through the entire long path of his evolution. If, at normal pressure, the oxygen content decreases to 16 percent, then oxygen starvation occurs, which causes a sudden loss of consciousness. For a person underwater, this situation is especially dangerous. An increase in the oxygen content in the inhaled mixture can cause poisoning, leading to pulmonary edema and inflammation. As pressure increases, the risk of oxygen poisoning increases. According to calculations, at a depth of 100 meters, the inhaled mixture should contain only 2-6 percent oxygen, and at a depth of 200 m - no more than 1-3 percent. Thus, breathing machines must ensure that the composition of the inhaled mixture changes as the submariner dives into depth. Medical support for deep-sea diving of a person in a soft suit is of paramount importance.

On the one hand, oxygen poisoning, and on the other, suffocation from a lack of the same oxygen, constantly threaten a person descending into the depths. But this is not enough. Everyone now knows about the so-called decompression sickness. Let's remember what it is. At high pressure, the gases that make up the breathing mixture dissolve in the diver’s blood. The majority of the air a diver breathes is nitrogen. Its importance for respiration is that it dilutes oxygen. With a rapid drop in pressure, when the diver is raised to the surface, excess nitrogen does not have time to be removed through the lungs, and nitrogen bubbles form in the blood, and the blood seems to boil. Nitrogen bubbles clog small blood vessels, causing weakness, dizziness, and sometimes loss of consciousness. These are manifestations of decompression sickness (embolism). When bubbles of nitrogen (or other gas that makes up the respiratory mixture) enter the large vessels of the heart or brain, the blood flow in these organs stops, that is, death occurs.

To prevent decompression sickness, the diver's ascent must be done slowly, with stops, so that the so-called decompression of the body occurs, that is, so that the excess dissolved gas has time to gradually leave the blood through the lungs. Depending on the depth of the dive, the ascent time and the number of stops are calculated. If a diver spends several minutes at great depths, then the time for his descent and ascent is calculated in several hours.

What has been said once again confirms the simple truth that a person cannot live in the water element, which once gave birth to his distant ancestors, and he will never leave the earth’s firmament.

But to understand the world, including studying the ocean, people persistently strive to master the ocean depth. People performed deep dives in soft diving suits, without even equipment such as scuba gear.

The first to descend to a record depth of 135 meters was the American Mac Nol in 1937, and two years later, Soviet divers L. Kobzar and P. Vygularny, breathing a helium mixture, reached a depth of 157 meters. It took ten years after that to reach the 200 meter mark. Two other Soviet divers, B. Ivanov and I. Vyskrebentsev, descended to this depth in 1949.

In 1958, a scientist whose specialty was far from underwater diving became interested in diving. He was a young, then 26-year-old mathematician who already had the title of professor at the University of Zurich, Hans Keller. Acting secretly from other specialists, he designed the equipment, calculated the composition of gas mixtures and decompression times, and began training. A year later, using a device in the form of a diving bell, he sank to the bottom of Lake Zurich to a depth of 120 meters. G. Keller achieved record-breaking short decompression times. How he achieved this was his secret. He dreamed of a world record for diving depth.

The US Navy became interested in the work of G. Keller, and the next dive was scheduled for December 4, 1962 in the Gulf of California. It was planned to lower G. Keller and English journalist Peter Small from the American ship “Eureka” using a specially made underwater elevator to a depth of 300 meters, where they would hoist the Swiss and American national flags. From aboard the Eureka, the dive was monitored using television cameras. Soon after the elevator descended, only one person appeared on the screen. It became clear that something unexpected had happened. It was subsequently determined that there was a leak in the underwater elevator and both aquanauts lost consciousness. When the elevator was lifted aboard the ship, G. Keller soon came to his senses, and P. Small was already dead before the elevator was raised. In addition to him, another scuba diver from the support group, student K. Whittaker, died. The search for his body was fruitless. These are the sad results of violations of diving safety rules.

By the way, G. Keller then in vain chased the record: already in 1956, three Soviet divers - D. Limbens, V. Shalaev and V. Kurochkin - visited a depth of three hundred meters.

In subsequent years, the deepest dives were up to 600 meters! were carried out by divers from the French company Comex, which is engaged in technical work in the oil industry on the ocean shelf.

A diver in a soft suit and with the most advanced scuba gear can stay at such a depth in a matter of minutes. We do not know what urgent matters, what reasons forced the leaders of the mentioned French company to risk the lives of divers, sending them to extreme depths. We suspect, however, that the reason here is the most trivial - the same disinterested love of money, of profit.

Probably, a depth of 600 meters already exceeds the physiological limit of diving for a person in a soft diving suit. There is hardly any need to further test the capabilities of the human body; they are not limitless. In addition, the person has already been to a depth significantly exceeding the 600-meter line, although not in a diving suit, but in devices isolated from the external environment. It has long become clear to researchers that a person can be lowered to great depths without risk to his life only in strong metal chambers, where the air pressure corresponds to normal atmospheric pressure. This means that it is necessary, first of all, to ensure the strength and tightness of such chambers and to create an air supply with the possibility of removing exhaust air or regenerating it. Ultimately, such devices were invented, and researchers descended into them to great depths, right down to the extreme depths of the World Ocean. These devices are called bathyspheres and bathyscaphes. Before getting acquainted with these devices, we ask readers to be patient and read our brief history of this issue on the next page of the Knowledge is Power website.

© Vladimir Kalanov,
"Knowledge is power"

>>Pressure at the bottom of seas and oceans. Deep sea exploration

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Hello dear readers! In this post, the main topic will be the exploration of the world's oceans. The ocean is very beautiful and tempting, it is home to many different species of fish and more, the ocean also helps our Earth in producing oxygen and plays an important role in its climate. But people, relatively recently, began to study it in detail, and were surprised by the results... Read more about this...

is a science that is associated with the study. It also helps us to significantly deepen our knowledge about natural forces, including mountain building, earthquakes, and volcanic eruptions.

The first explorers believed that the ocean was an obstacle to reaching distant lands. They were of little interest in what was in the depths of the ocean, despite the fact that the world's oceans occupy more than 70% of the Earth's surface.

It is for this reason that even 150 years ago the prevailing idea was that the ocean floor was a huge plain devoid of any relief elements.

Scientific exploration of the ocean began in the 20th century. In 1872 - 1876 The first serious voyage for scientific purposes took place on board the British ship Challenger, which had special equipment and its crew consisted of scientists and sailors.

In many ways, the results of this oceanographic expedition enriched human knowledge about the oceans and their flora and fauna.

In the depths of the ocean.

On the Challenger, for measuring the ocean depths, there were special lines, which consisted of lead balls weighing 91 kg, these balls were attached to a hemp rope.

It could take several hours for such a line to be lowered to the bottom of a deep-sea trench, and on top of that, this method quite often did not provide the required accuracy for measuring large depths.

In the 1920s, echo sounders appeared. This made it possible to determine the ocean depth in just a few seconds based on the time elapsed between the sending of the sound pulse and the reception of the signal reflected by the bottom.

The vessels, which were equipped with echo sounders, measured the depth along the route and obtained a profile of the ocean floor. The newest deep-sea sounding system, Gloria, has been installed on ships since 1987. This system made it possible to scan the ocean floor in strips 60 m wide.

Previously used to measure ocean depths, weighted survey lines were often equipped with small soil tubes for taking soil samples from the ocean floor. Modern samplers are heavy and large, and they can dive to a depth of up to 50 m in soft bottom sediments.

Major discoveries.

Intensive ocean exploration began after World War II. Discoveries in the 1950s and 1960s related to oceanic crust rocks revolutionized geosciences.

These discoveries proved the fact that the oceans are relatively young, and also confirmed that the movement of lithospheric plates that gave rise to them continues today, slowly changing the appearance of the earth.

The movement of lithospheric plates causes volcanic eruptions and earthquakes, and also leads to the formation of mountains. The study of oceanic crust continues.

The ship "Glomar Challenger" in the period 1968 - 1983. was on a circumnavigation. It provided geologists with valuable information by drilling holes in the ocean floor.

The United Oceanographic Deep Drilling Society's vessel Resolution performed this task in the 1980s. This vessel was capable of underwater drilling at depths of up to 8300 m.

Seismic surveys also provide data about ocean floor rocks: shock waves sent from the surface of the water are reflected differently from different layers of rock.

As a result, scientists receive very valuable information about possible oil deposits and the structure of rocks.

D Other automatic instruments are used to measure current speed and temperature at different depths, as well as to take water samples.

Artificial satellites also play an important role: they monitor ocean currents and temperatures that affect .

It is thanks to this that we receive very important information about climate change and global warming.

Scuba divers in coastal waters can easily dive to depths of up to 100 m. But to depths that are greater, they dive by gradually increasing and releasing pressure.

This diving method is successfully used to detect sunken ships and in offshore oil fields.

This method gives much more flexibility when diving than a diving bell or heavy diving suits.

Submersibles.

The ideal means for exploring the oceans is submarines. But most of them belong to the military. For this reason, scientists created their devices.

The first such devices appeared in 1930–1940. American Lieutenant Donald Walsh and Swiss scientist Jacques Piccard, in 1960, set a world record for diving in the deepest area of ​​the world - in the Mariana Trench of the Pacific Ocean (Challenger Trench).

On the bathyscaphe "Trieste" they descended to a depth of 10,917 m, and in the depths of the ocean they discovered unusual fish.

But perhaps the most impressive in the more recent past were the events associated with the tiny bathyscaphe "Alvin", with the help of which in 1985 - 1986. The wreckage of the Titanic was studied at a depth of about 4,000 m.

We conclude: the vast world ocean has been studied very little and we have to study it more and more in depth. And who knows what discoveries await us in the future... This is a big mystery that is gradually opening up to humanity thanks to the exploration of the world's oceans.