All sailing directions and atlases indicate that the average depth of the Black Sea is 1300 meters. From the surface of the water to the bottom of the sea basin, indeed, on average, almost one and a half kilometers, but what we used to consider the sea has a depth that is several times less, about 100 meters. Below lurked a lifeless and deadly poisonous abyss. This discovery was made by a Russian oceanographic expedition in 1890. Soundings have shown that the sea is almost entirely filled with dissolved hydrogen sulfide, a poisonous gas with the smell of rotten eggs. In the center of the sea, the hydrogen sulfide zone approaches the surface by about 50 meters; closer to the shores, the depth from where the dead zone begins increases to 300 meters. In this sense, the Black Sea is unique, it is the only one in the world without a solid bottom.

A liquid convex lens of dead water underlies a thin upper layer, where all sea ​​life. The underlying lens breathes, swells, breaking through to the surface from time to time due to driving winds. Major breakthroughs are less common, the last one occurred during the Yalta earthquake of 1928, when even far from the sea there was a strong smell of rotten eggs and thunder lightning flashed on the sea horizon, leaving burning pillars in the sky (H2S hydrogen sulfide is a combustible and explosive poisonous gas).

Until now, there are disputes about the source of hydrogen sulfide in the depths of the Black Sea. Some consider the reduction of sulfates by sulfate-reducing bacteria during the decomposition of dead organic matter as the main source. Others adhere to the hydrothermal hypothesis, i.e. hydrogen sulfide inflows from cracks in seabed. However, there are no contradictions here, apparently, both reasons are at work. The Black Sea is arranged in such a way that its water exchange with the Mediterranean Sea goes through the shallow Bosphorus threshold. The Black Sea water, desalinated by river runoff, and therefore lighter, goes into the Sea of ​​​​Marmara and further, and towards it, more precisely under it, through the Bosphorus threshold into the depths of the Black Sea, saltier and heavier Mediterranean water rolls down. It turns out something like a giant sump, in the depths of which hydrogen sulfide has gradually accumulated over the past six to seven thousand years.

Today, this dead layer makes up over 90 percent of the volume of the sea. In the 20th century, as a result of sea pollution with organic anthropogenic matter, the boundary of the hydrogen sulfide zone rose from the depth by 25–50 meters. Simply put, oxygen from the upper thin layer of the sea does not have time to oxidize the hydrogen sulfide that supports it from below. Ten years ago, this problem was considered one of the priorities in the countries of the Black Sea region. Hydrogen sulfide is a highly toxic and explosive substance. Poisoning occurs at a concentration of 0.05 to 0.07 mg/m3. The maximum permissible concentration of hydrogen sulfide in the air of populated areas is 0.008 mg/m3. According to a number of experts and scientists, a charge equivalent to Hiroshima is enough to detonate hydrogen sulfide in the Black Sea. At the same time, the consequences of the catastrophe will be comparable to those if an asteroid with a mass 2 times less than the mass of the Moon crashed into our Earth.

Total hydrogen sulfide in the Black Sea is more than 20 thousand cubic kilometers. Now the problem has been forgotten due to unclear circumstances. True, this problem has not disappeared. In the early 1950s, an upwelling current (upwelling) brought a hydrogen sulfide cloud to the surface in Walvis Bay (Namibia). Up to a hundred and fifty miles inland, the smell of hydrogen sulfide was felt, the walls of houses darkened. The smell of rotten eggs already means exceeding the MPC (maximum permissible concentration). In fact, the inhabitants of South West Africa survived then a "soft" gas attack. In the Black Sea, a gas attack could be much more severe. Suppose someone comes up with the idea of ​​mixing the sea, or at least part of it. Unfortunately, this is technically feasible. In the relatively shallow northwestern part of the sea, somewhere halfway between Sevastopol and Constanta, you can conduct an underwater nuclear explosion relatively low power. On the shore, it will be noticed only by instruments. But after a few hours there, on the shore, they will smell rotten eggs. Under the most favorable set of circumstances, in a day, two-thirds of the sea will turn into a fraternal cemetery of marine organisms. In case of unfavorable conditions, coastal cemeteries will also turn into fraternal cemeteries. settlements where non-marine organisms live. In the previous two phrases, the evaluative adjectives “prosperous” and “unfavorable” can be interchanged, this is from what position to look.

Poison Sea
If from the position of a person or a group of people who set themselves the goal of paralyzing the peoples of half a dozen countries at once with horror, then it is necessary to change. However, the greed of the oil and gas companies is worse than any Ben with his Frankincense. Feeling that the end of the era of hydrocarbon raw materials is very close, and is measured in a couple of decades, after which the era of total stagnation will come, and the complete decline of the raw materials economy, businessmen from the state in agony and in desperation threw pipes to hell high pressure for a fuel pipeline right along the bottom of the Black Sea. Greater obscurantism was hard to expect. This is such a one-time weekend construction, which cannot be repaired and prevented in the conditions of explosive hydrogen sulfide. Everyone still remembers the Adler-Novosibirsk passenger train, which burned down completely due to a fuel line failure. You don't have to be an expert chemist or physicist to understand what will happen if a fuel line breaks in the deep layers of hydrogen sulfide in the Black Sea. No comments.

Thousands of businessmen who make resort money on the exploitation of the Black Sea do not suspect that their business will soon end, and the Black Sea coast will turn from a resort zone into an ecological disaster zone dangerous for human habitation. This is especially true of the Black Sea coast of the Caucasus, where, according to scientists, a large amount of hydrogen sulfide is most likely to be released into the atmosphere. Twenty years ago, having familiarized themselves with the calculations of scientists on the Black Sea, scientists built a graph of the decrease in the surface layer of water from 1890 to 2020. The continuation of the graph curve reached 15 meters of layer thickness by 2010. And it was already noted near the Caucasus in 2007. This was even reported on May 30, 2007 on the radio in Sochi. There were also reports of mass deaths of dolphins in the Black Sea. And the local people themselves felt a certain dead spirit from the sea. In the area of ​​New Athos, the sea is already different than it was 20-30 years ago, in the afternoon the water is muddy, yellow, dead fish and even dead animals.

Many businessmen realized the whole pointlessness of their ideas of participation in investing in the resort business on the Black Sea coast of the Caucasus. No one thinks about the fact that a catastrophe is coming, and it is not far off, but very close. Many local residents the feeling that the 2014 Olympics will be held as a parting of an unreasonable person with the Black Sea. Millions of people living on Black Sea coast will be forced to move away from the coast because of the danger of dying as a result of suffocation from hydrogen sulfide and lack of oxygen in the air. And before this total flight of residents from resort cities, mass diseases of residents of the coastal zone may begin with deaths. The end of the Black Sea resorts will come! This will be a worthy retribution of people for their admiration for the power of the Golden Calf, for their contempt for nature, for their ignorance of environmental safety issues. Indeed, with a reasonable approach to business, it is possible to turn the threatening troubles to the benefit of the economy and energy.

The water of the Black Sea contains silver and gold. If we extract all the silver in the water of the Black Sea, then this would amount to approximately 540 thousand tons. If all the gold was extracted, it would amount to approximately 270 thousand tons. Methods for extracting gold and silver from the waters of the Black Sea have long been developed. The very first primitive installations were based on ion exchangers, special ion-exchange resins that are capable of attaching ions of substances dissolved in water to themselves. But only Turkey, Bulgaria and Romania extract silver and gold from the waters of the Black Sea in an industrial way, using their own special technologies.

It is known that at a depth below 50 meters, the deep layers of the Black Sea are a colossal storehouse of hydrogen sulfide (about a billion tons). Hydrogen sulfide is a combustible gas that, when burned, gives a corresponding amount of heat. In other words, it is a fuel that can and should be used. During the combustion of hydrogen sulfide according to the reaction: 2H2S + 3O2 \u003d 2H2O + 2SO2, heat is released in an amount of about 268 kcal (with an excess of oxygen). Compare with the amount of heat released during the combustion of hydrogen in oxygen according to the reaction: H2 + 1/2 O2 > H2O (about 68.4 kcal/mol is released). Since sulfur dioxide (a harmful product) is formed in the first reaction, it is of course better to use hydrogen as a fuel in the composition of hydrogen sulfide, which can be obtained by heating hydrogen sulfide according to the reaction:

H2S H2+S3 Decomposition of hydrogen sulfide requires slight heating. Reaction (3) will also make it possible to obtain sulfur from the Black Sea water. If we carry out reactions for the combustion of hydrogen sulfide in atmospheric oxygen:

2H2S + 3O2 = 2H2O + 2SO2,

Then, according to the combustion of the resulting sulfur dioxide:

SO2+? O2 = SO3

Then, according to the interaction of three sulfur oxides with water:

SO3 + H2O = H2SO4

As you know, we can get sulfuric acid with the associated production of heat in the appropriate amount. In the production of sulfuric acid, about 194 kcal / mol is released. Thus, either hydrogen and sulfur or sulfuric acid can be obtained from the water of the Black Sea with the associated production of heat in the appropriate amount. It remains only to extract hydrogen sulfide from the deep layers of the sea. This is confusing at first.

One of the scientific developments proceeds from the fact that in order to lift the deep layers of sea water saturated with hydrogen sulfide, it is not at all necessary to expend energy on pumping it. According to this scientific development, it is proposed to lower a pipe with strong walls to a depth of up to 80 meters and once raise water from a depth through it in order to obtain a gas-water fountain in the pipe due to the difference in the hydrostatic pressure of water in the sea at the level of the lower cut of the channel and the pressure of the gas-water mixture at that the same level inside the channel (recall that every 10 meters the pressure in the sea rises by one atmosphere). This is an analogy with a bottle of champagne. By opening the bottle, we lower the pressure in it, because of which the gas begins to be released in the form of bubbles, and so intensely that the bubbles, as they rise, push the champagne in front of them. Pumping out the first time a column of water from the pipe - this will just be the opening of the cork.

It is reported that a group of scientists from Kherson conducted a ground experiment back in 1990, confirming the operation of such a fountain until hydrogen sulfide in the sea runs out. The full-scale marine experiment also ended successfully. A very revealing example, when the existence of life is under threat, the planet is saved by a bunch of lone heroes, who, in addition, are hindered by the government and everything around. And where is the whole state potential, with its scientific power, computers, programs, being asked at this time?

Black Sea disaster

Skeptics can easily check the data on their fingers by sailing further into the sea and lowering a thick hose with a load on the end into the water. It is not only recommended to smoke at this time, so that it does not work out, as in Chukovsky's poems. Many probably remember the words of Korney Chukovsky's poem: "And the chanterelles took matches, went to the blue sea, lit the blue sea." But few people know that children's poems by Korney Chukovsky are very carefully studied by astrologers: as in the quatrains of Michel Nostradamus, these poems contain a lot of interesting predictions. Leonid Utyosov helped with geo-referencing of the "place of arson": "The bluest in the world is my Black Sea!" Until recently, this sea was practically the only resting place for residents. whole country- THE USSR. Even the great strategist, Ostap Bender, marked himself there in search of twelve chairs. And he did not pay for the small with his life in Yalta at the time of the famous Crimean earthquake of 1928. Coincidentally, there was a thunderstorm at the time of the earthquake. Lightning struck everywhere. Including at sea. And suddenly something completely unexpected happened: columns of flame began to break out of the water to a height of 500-800 meters. Here are such matches and chanterelles. Chemists know two types of hydrogen sulfide oxidation reactions: H2S + O = H2O + S;

H2S + 4O + to = H2SO4.

As a result of the first reaction, free sulfur and water are formed. The second type of H2S oxidation reaction proceeds explosively during the initial thermal shock. As a result, sulfuric acid is formed. It was the second course of the H2S oxidation reaction that was observed by the inhabitants of Yalta during the earthquake in 1928. Seismic tremors stirred deep-sea hydrogen sulfide to the surface. The electrical conductivity of an aqueous solution of H2S is higher than that of pure sea water. Therefore, electric lightning discharges most often fell into areas of hydrogen sulfide raised from the depth. However, a significant layer of pure surface water extinguished the chain reaction. By the beginning of the 20th century, the upper inhabited water layer in the Black Sea was 200 meters. Thoughtless technogenic activity has led to a sharp reduction in this layer. Currently, in some places its thickness does not exceed 10-15 meters. During a severe storm, hydrogen sulfide rises to the surface, and vacationers can smell a characteristic smell.

At the beginning of the century, the Don River supplied up to 36 km3 of fresh water to the Azov-Black Sea basin. By the beginning of the 1980s, this volume had decreased to 19 km3: the metallurgical industry, irrigation facilities, field irrigation, and city water pipes. Entering the Volgodonsk nuclear power plant took another 4 km3 of water. A similar situation occurred during the years of industrialization in other rivers of the basin. As a result of the thinning of the surface inhabited water layer, there has been a sharp reduction in biological organisms in the Black Sea. So, for example, in the 50s, the number of dolphins reached 8 million individuals. Nowadays, meeting dolphins in the Black Sea has become a rarity. Fans of underwater sports sadly observe only the remnants of miserable vegetation and rare flocks of fish, rapans have disappeared. Few people think, for example, that all marine souvenirs sold along the Black Sea coast (decorative shells, mollusks, starfish, corals, etc.) have nothing to do with the Black Sea. Traders bring these goods from other seas and oceans. And in the Black Sea, even mussels have almost disappeared. Since ancient times, sturgeon, horse mackerel, mackerel, and bonito, which have been harvested since ancient times, disappeared back in the 1990s as commercial species. (That is, there are no longer scows full of mullet that Kostya brought to Odessa, and in general, no one has adored anyone for a long time).

But this is not the worst! If the Crimean earthquake happened today, then everything would end in a global catastrophe: billions of tons of hydrogen sulfide are covered by the thinnest water film. What is the scenario of a probable cataclysm? As a result of the primary thermal shock, a volumetric explosion of H2S will occur. This can lead to powerful tectonic processes and shifts. lithospheric plates, which in turn will cause devastating earthquakes throughout the globe. But that is not all! As a result of the explosion, billions of tons of concentrated sulfuric acid will be released into the atmosphere. It will no longer be modern weak acid rain after our plants and factories. Acid showers after the explosion of the Black Sea will burn out all living and non-living things on the planet! Or almost everything. Nature is wise! The origin of life on the planet is too expensive from an energy-informational point of view. Virtually everyone biological forms on earth - the carbon basis of the structure of the organism, and DNA with left polarization. But there are, as modern microbiologists know, 4 types of bacteria with right-handed DNA polarization. These bacteria "live" on the planet in conditions completely isolated from other forms. They were found in the sour boiling water of volcanoes!

Apparently, it is these bacteria that will give a new impetus to the development of life on Earth if our civilization fails to become intelligent and still ends up with global suicide!
P.S. In order to clarify, one more detail needs to be clarified: when reading the article, it may seem that at the depth of the Black Sea there is not a solution of hydrogen sulfide in water, but a huge bubble of pure hydrogen sulfide gas, which, for unknown reasons, cannot float to the surface on its own and can explode ... In fact, it's just a solution of hydrosulfide acid, i.e. It's just mineral water. The same as in many hydrogen sulfide mineral springs that hit the surface and at the same time do not explode anything around.

So, as you can see, there are many opinions on this matter.

Imagine - you are relaxing in a resort. And you decide to get up early in the morning, look at the sea dawn. You get dressed, you go to the sea - and you see something unimaginable. The entire coast is covered with fish, jellyfish, some kind of generally unseen animals. It's scary to approach. And the smell of decay in the air. But if you sit by the shore, look at this miracle, you will notice that the marine inhabitants on the shore occasionally move, twitch. And if you look even longer, you can see that they are gradually shifting back to the sea. And by eight or nine o'clock, when most of the vacationers go to the sea, the coast is already empty and does not resemble a worldwide catastrophe.

What happened? A rather rare but common thing for the Black Sea happened - a small release of hydrogen sulfide. The smell of which you may have smelled.

Due to the fact that the upper layer of the Black Sea water is weakly mixed with the lower one, oxygen rarely reaches the sea bottom. And where there is no oxygen, decay begins there. One of the results of decay is the release of hydrogen sulfide. Well, since the upper, fresher layer of water rarely mixes with the lower, more salty one, this poisonous gas accumulates at the bottom of the Black Sea in huge quantities. And occasionally, when its amount exceeds conceivable limits, it comes out in the form of huge bubbles. Or small bubbles. As the bubble passes through the upper, inhabited layer of the Black Sea, it poisons fish, jellyfish and other living creatures. And in an unconscious state they are taken ashore by the sea. Well, then, when they leave on land, the fish and shrimps run back to the sea.


Scheme of hydrogen sulfide formation in the Black Sea.

Why does a gas that is lighter than water not float? Scientists believe that the pressure of the upper layers of water is to blame - 200 meters of water is no joke. And if this water suddenly disappeared, the Black Sea would boil from the hydrogen sulfide released in the form of gas.

Why do hydrogen sulfide emissions occur from the depths? For two reasons - an excessive increase in the content of this poison and underwater earthquakes. A small displacement of the earth's crust is enough, and the shock wave raises a huge gas bubble from the bottom of the sea. So, during the Crimean earthquake of 1927 in Yalta, residents watched the sea burn - hydrogen sulfide, which rose from below, interacted with the air and flared up. Although, according to other sources, it was not hydrogen sulfide, but methane. And the concentration of hydrogen sulfide in water is so low that it cannot form gas bubbles, boil and poison animals.

But it is up to scientists to determine what will happen if hydrogen sulfide decides to rise to the surface. We just need to know that there is not a single recorded case when hydrogen sulfide from the bottom of the Black Sea led to the death of people. Or even simple poisoning.

How did the Black Sea appear?

The turbulent geological past fell to the lot of the area where the Black Sea is now located. It is still impossible to give a complete history of the Black Sea. Little information has yet been accumulated. And yet, in general, the picture of the geological past of the Black Sea does not raise fundamental objections from any of the geologists.

Before the beginning of the Tertiary period, that is, at times distant from us by 30-40 million years, through Southern Europe And Central Asia from west to east stretched a vast ocean basin, which in the west communicated with Atlantic Ocean, and in the east - with the Pacific. It was the salt sea of ​​Tethys. By the middle of the Tertiary period, as a result of the uplift and lowering of the earth's crust, Tethys first separated from Pacific Ocean and then from the Atlantic.

In the Miocene (from 3 to 7 million years ago) significant mountain-building movements take place, the Alps, Carpathians, Balkans, and the Caucasus Mountains appear. As a result, the Tethys Sea shrinks in size and is divided into a series of brackish basins. One of them - the Sarmatian Sea - stretched from the present Vienna to the foot of the Tien Shan and included the modern Black, Azov, Caspian and Aral Sea. The Sarmatian Sea, isolated from the ocean, gradually became heavily desalinated by the waters of the rivers flowing into it, perhaps even to a greater extent than the modern Caspian. The marine fauna that remained from the Tethys partly died out, but it is curious that such typically oceanic animals as whales, sirens and seals lived in the Sarmatian Sea for a long time. Later they were gone.

At the end of the Miocene and the beginning of the Pliocene (2-3 million years ago), the Sarmatian basin decreases to the size of the Meotic Sea (basin). At this time, a connection with the ocean reappears, the water becomes saline, and sea ​​views animals and plants.


Meotic Sea.

In the Pliocene (1.5-2 million years ago), communication with the ocean again completely ceased, and an almost fresh Pontic lake-sea appeared on the site of the salty Meotic Sea. In it, the future Black and Caspian Seas communicate with each other in the place where the North Caucasus is now located. In the Pontic Lake-Sea, the marine fauna disappears and the brackish-water fauna is formed. Its representatives are still preserved in the Caspian Sea, in the Azov and in the desalinated regions of the Black Sea.


Pontic Sea.

This part of today's Black Sea fauna is united under the name "Pontic relics", or "Caspian fauna", since the best way it was preserved in the desalinated Caspian Sea. At the end of the Pontic period of the history of the reservoir, as a result of the uplift of the earth's crust in the area North Caucasus gradually there was a separation of the basin of the Caspian Sea proper. Since then, the development of the Caspian, on the one hand, and the Black and Azov Seas, on the other, has taken independent paths, although temporary connections between them still arose.

With the onset of the Quaternary or ice age salinity and composition of the inhabitants of the future Black Sea continue to change, and its shape is changing. At the end of the Pliocene (less than 1 million years ago), the Pontic lake-sea decreased in size to the boundaries of the Chaudinsky lake-sea. Highly desalinated, isolated from the ocean and inhabited by Pontic-type fauna. The Sea of ​​\u200b\u200bAzov at that time, apparently, did not exist yet.


Chaudinsky lake-sea.

As a result of ice melting at the end of the Mindel glaciation (about 400-500 thousand years ago), the Chaudin Sea is filled with melt water and turns into the Ancient Euxinian basin. In outline, it resembled modern Black and Sea of ​​Azov. In the northeast, through the Kumo-Manych depression, it communicated with the Caspian Sea, and in the southwest, through the Bosphorus, with the Sea of ​​Marmara, which was then separated from the Mediterranean and also experienced a period of strong desalination. The fauna of the Ancient Euxinian basin was of the Pontian type.


Ancient Euxinian basin.

During the Ris-Wurm interglacial period (100-150 thousand years ago), a new stage in the history of the Black Sea begins: for the first time since the Tethys, due to the formation of the Dardanelles, there is a connection between the future Black Sea and the Mediterranean Sea and the ocean. The so-called Karangat basin, or the Karangat Sea, is formed. Its salinity is higher than that of the modern Black Sea. With ocean waters, various representatives of real marine fauna and flora penetrate into it. They filled most of the reservoir and pushed the brackish-water Pontic species into desalinated bays, estuaries, and river mouths. But this pool has also changed.


Karangat Sea.

18-20 thousand years ago, on the site of the Karangat Sea, there was already the Novoevksinskoye Lake-Sea. This coincided with the end of the last, Wurm, glaciation. The sea was filled with melt water, again isolated from the ocean and heavily desalinated. The salt-loving oceanic fauna and flora are dying out again, and the Pontian species, which survived the difficult Karangat period for them in the estuaries and estuaries, came out of their shelters and once again populated the entire sea.


Novoevksinskoe Sea.

This went on for about 10 thousand years or a little more, after which the newest phase in the life of the reservoir began - the modern Black Sea was formed. However, the word "modern" in this case does not at all mean identity with today's sea. Initially (about 7, and according to some authors, even about 5 thousand years ago), a connection was formed with the Mediterranean Sea and the World Ocean through the Bosphorus and the Dardanelles. Then the gradual salinization of the Black Sea began. After another 1-1.5 thousand years, the salinity of the water was created, sufficient for the existence of a large number of mediterranean species. Today, about 80 percent of the representatives of the Black Sea fauna are "newcomers" from mediterranean sea, and the Pontic relics again retreated into desalinated bays and estuaries, as during the existence of the Karangat basin.

Analyzing the various periods of the history of the Black Sea, we can conclude that the current phase is just an episode between past and future transformations. In the future, the most unexpected changes are possible.

What is the current appearance of the Black Sea? This is a fairly large body of water with an area of ​​420,325 square kilometers. Its average depth is 1290 meters, and the maximum reaches 2212 meters and is located north of Cape Inebolu on the coast of Turkey. The calculated volume of water is 547,015 cubic kilometers. The coasts of the sea are little indented, with the exception of the northwestern part, where there are a number of bays and coves. There are not many islands in the Black Sea. One of them - Snake - is located forty kilometers east of the Danube Delta, the other - Schmidt Island (Berezan) - is located near Ochakov and the third, Kefken, is not far from the Bosphorus Strait. The area of ​​the largest island - Snake - does not exceed one and a half square kilometers.

The Black Sea exchanges waters with two other seas: through the Kerch Strait in the northeast with the Sea of ​​Azov and through the Bosphorus Strait in the southwest with the Sea of ​​Marmara. The length of the Kerch Strait is 45 kilometers, the smallest width is about 4 kilometers and the depth is 7 meters. The length of the Bosporus Strait is 33 kilometers, the smallest width is 550 meters, and the smallest depth is about 30 meters. Thus, the Black Sea exchanges water with its neighbors at the very surface, and not over the entire depth.

In general, they say that the bottom of the Black Sea resembles a plate with its relief - it is deep and even with shallow edges along the periphery.

Blue? Blue? Green? We can safely say that the Black Sea is not "the bluest in the world." The color of the water in the Red Sea is much bluer than in the Black Sea, and the Sargasso Sea is the bluest. What determines the color of the water in the sea? Some people think it's from the color of the sky. This is not entirely true. The color of water depends on how sea water and its impurities scatter sunlight. The more impurities, sand and other suspended particles in the water, the greener the water. The saltier and cleaner the water, the bluer it is. Many flows into the Black Sea major rivers, which desalinate water and carry with them many different suspensions, so the water in it is rather greenish-blue, and off the coast it is rather green.

In addition.

Some people know, and for some, maybe this is news, but: in the Black Sea, at a level of 50-100 meters from the surface, there is a giant layer of hydrogen sulfide. In some seas there is a similar, but not on such a scale. Yes, and the layer increases and at the same time rises to the surface.

It is because of this layer that the sea has the smallest number of inhabitants: there is a dead zone under the layer. Where is this layer from? There are several equivalent hypotheses for this, but none of them falls short of a full-fledged theory. What will happen when hydrogen sulfide comes to the surface? Yes mass death will.

Under the cut - a couple of articles on this topic, which I found the most interesting.

Danger lurks at the bottom of the sea!

The Black Sea, shining under the rays of the warm southern sun - what could be more beautiful? Huge, alluring, clean, transparent and incredibly beautiful... Surely, these are the epithets that come to each of us at the mere thought of this sea - a source of inspiration for poets and a favorite vacation spot for many modern citizens. But few people know that at the bottom of the amazing sea with the proud name Chernoe, a mortal danger lurks - a lifeless abyss filled with poisonous, flammable, explosive gas with a disgusting smell of rotten eggs.

As a result of a large-scale oceanographic expedition carried out back in 1890, it was found that about 90% of the volume of the sea is filled with hydrogen sulfide and only 10% - clean water not contaminated with poisonous gas. In the lower layer of the sea, neither animals nor plants are able to survive, but only certain types bacteria. A deadly gas fills a huge space, killing all life in its path. The entire volume of sea water is divided into two parts, surface water can reach the bottom of the sea only after hundreds of years. This property is unique, in the whole world there is not a single sea without a solid bottom.

The maximum depth of the Black Sea is just over two kilometers. The upper layer of water, where the life of marine life is concentrated, has a depth of only 100 meters, and in some places the thickness of the clear water layer barely reaches 50 meters. Under it is a liquid lens of "dead" water, periodically breaking out and showing its destructive essence. Major breakthroughs are rare enough, but each of them brings a lot of harm. marine life. According to experts, the explosion of all hydrogen sulfide can be compared to the meeting of the Earth with an asteroid with a mass half that of the Moon.

About the causes of the appearance of hydrogen sulfide

Disputes over the cause of the appearance of hydrogen sulfide at the bottom of the Black Sea have not subsided so far. The poisonous gas could have come from cracks in the seafloor, or it could have come from the specific action of bacteria. Without oxygen in the deep layers of the Black Sea, only anaerobic bacteria, which are involved in the decomposition of the remains of living organisms, can survive. As a result of this decomposition, hydrogen sulfide can be formed. According to another version, poisonous gas could be formed due to the specific communication of the sea with the oceans through the narrow Bosporus. A certain amount of water penetrates from the Mediterranean Sea into the Black Sea, turning it into a kind of sump, which has accumulated a large amount of hydrogen sulfide over many years.

Even 10 years ago, the issue of poisonous gas was considered one of the top priorities in the Black Sea countries, but today the hydrogen sulfide threat seems to have been completely forgotten. However, this problem has not disappeared and is not going to disappear. But how real is the danger? Perhaps everything is not so scary and hydrogen sulfide, hidden in the depths of the seabed, will remain there forever, without disturbing anyone? And what forces can contribute to the explosion of a huge amount of poisonous gas? These questions can be answered by the following reasoning.

The first reason for a possible explosion

Imagine hypothetically that at the bottom Black Sea there was an explosion. Is it worth specifying what consequences will be experienced by marine organisms and inhabitants of coastal areas? At a minimum, the first ones will die, as a maximum - alas, both of them ... It sounds intimidating, but who needs to blow up the Black Sea? There are hardly any good reasons for this, even among the most notorious terrorists. But here is the time to remember what causes all the troubles on our planet? That's right - from human actions, often uncontrolled and irresponsible. One has only to wait for the moment when oil and gas companies will lay pipelines along the bottom of the Black Sea. The complexity of the repair and maintenance of such structures in an explosive environment will sooner or later lead to their failure and, as a result, to a large-scale explosion in the hydrogen sulfide layer. What happens next is easy to guess. The Black Sea region can become a zone of ecological disaster, dangerous for people's lives. Innocent people will pay for someone's thoughtless actions and neglect of environmental safety issues.

The second reason for a possible explosion

The cause of the explosion of hydrogen sulfide can be not only human irresponsibility, but also the vagaries of nature. The last such explosion occurred in 1927 during a strong earthquake in Yalta. Two months before the incident, a phenomenon occurred that surprised local residents - local fishermen noticed a strange wave of water and a small swell, as if boiling for unknown reasons. A few minutes later, the eyewitnesses were deafened by an underwater roar - it was a "preparatory" push coming from the depths of the sea.
In the dead of night on September 12, 1927, the Crimean peninsula experienced the full power of an eight-magnitude earthquake. The epicenter was located near Yalta, but many other Crimean cities also suffered, serious damage to buildings and communications was recorded, crops died in the fields, and collapses and landslides occurred in the mountains.

But the most incredible phenomena occurred at sea. Eyewitnesses testified that the perturbations of the earth's crust were accompanied by a disgusting stench and flashes directed from the surface of the sea surface to the heavens. Pillars of fire, shrouded in smoke, reached several hundred meters in height. The Black Sea was burning, the same smell of rotten eggs was in the air. Lightning discharges hit precisely those places where hydrogen sulfide was concentrated. There were many versions about the reasons for this phenomenon, according to one of them, it was poisonous gas on the seabed that became the source of the explosion.
If the Crimean earthquake happened in our time, when hydrogen sulfide is under a thin film of water, everything would turn into a global catastrophe. Experts who are seriously puzzled by this problem paint a sad picture: an explosion of hydrogen sulfide in the Black Sea can lead to strong tectonic shifts and the release of a large amount of sulfuric acid into the atmosphere. acid rain, poisoned air, a series of earthquakes - that's what the population of coastal areas can expect.

The third reason for a possible explosion

Hydrogen sulfide can explode for another reason. Over time, the top layer can simply become thinner, especially since in Lately there is a constant tendency towards a slow but sure emaciation of the layer of pure water. According to scientists, in a few years the thickness of the protective layer will be no more than 15 meters. All the fault will be anthropogenic pollution of sea water, which occurs regularly. Already, in some places, the presence of hydrogen sulfide is recorded at such a depth, but experts assure that the poisonous gas does not come from the bottom of the sea at all, but from the surface of the earth. Hydrogen sulfide, formed from fertilizers that have fallen into the sea, disappears during autumn storms.

Ways to solve the problem

Experts say that the tragedy can be avoided, it is enough to act competently and in a coordinated manner for the benefit of the Black Sea. Scientists are not sitting idle - they already have some developments in stock, the main idea of ​​​​which is to use the Black Sea hydrogen sulfide as a fuel, because the poisonous gas releases a huge amount of heat during combustion. Sounds tempting, but how do you extract hydrogen sulfide from the seafloor? According to a group of scientists from Kherson, this is not difficult to do: it is enough to lower a strong pipe to a depth of about 80 meters and raise water through it once. Due to the pressure difference, a fountain is formed, consisting of gas and water. Simply put, an effect similar to opening a bottle of champagne will occur. In 1990, the authors of the idea made an experiment proving the possibility of such a fountain to work for a long period until hydrogen sulfide comes out.
Another method has also been developed for lifting hydrogen sulfide to the sea surface. Scientists proposed to pipe fresh water with a lower density than sea water. Several of these pipes, creating the effect of artificial aeration, would stop the spread of hydrogen sulfide and gradually completely eliminate it. Such manipulations are already being effectively carried out for cleaning aquariums and small ponds.

Similar developments, like many others in countries former Union, have remained unclaimed. People who have the opportunity to solve the problem turn a blind eye to it. I would like to hope that such self-confidence will not lead to sad consequences, and the Black Sea will remain for us as clean, transparent and incredibly fabulously beautiful.

When in my distant childhood I read a poem by K.I. Chukovsky's "Confusion", I was most surprised by the pictures of the burning sea. It seemed like something really incredible, absurd. However, recently I learned that the sea can really catch fire, and the facts of its ignition are already known to history.

So, in 1927, when there was a major earthquake in the Crimea, fires in the Black Sea were recorded near Evpatoria and Sevastopol. However, then the fire at sea was caused by the release of methane - natural gas, the release of which from the bowels was provoked by an earthquake. The spectacle was amazing. Of course, this news was not advertised, but when journalists got their hands on information about those events in the 90s of the 20th century, the newspapers burst into sensationalism. The explosion in popularity of these articles was caused not so much by a methane release as by a distortion of facts: the newspapers wrote about the fire not of methane, but of hydrogen sulfide, after which it was concluded that a global catastrophe was possible.

There was something to be desperate about. Hydrogen sulfide, as you know, is a fairly stable combination of hydrogen and sulfur (decomposes only at a temperature of 500 degrees), a colorless poisonous gas with a pungent smell of rotten eggs. The hydrogen sulfide zone in the Black Sea was discovered in 1890 by N.I. Andrusov. Already then guessed large quantities deposits of this gas. So, if you lower a metal load on a rope into the depths, then it will return completely black due to deposits of sulfites on it - salts that hydrogen sulfide forms with metals. (One of the hypotheses says that the Black Sea owes its name to this phenomenon).

However, at the beginning of the 20th century, it turned out that there is not just a lot of hydrogen sulfide in the Black Sea, but a lot - below a depth of 150-200 m, a continuous hydrogen sulfide zone begins. It is distributed, however, unevenly: near the coast, its upper boundary reaches 300 m, while in the center, hydrogen sulfide approaches a depth of about 100 m. Total hydrogen sulfide dissolved in the Black Sea reaches 90%, so that all life is concentrated in a small surface layer, and there is no deep-sea fauna in the Black Sea.

Hydrogen sulfide is not some unique property only the Black Sea, it is found in soft remains at the bottom of all seas. The accumulation of this gas is due to the fact that oxygen practically does not penetrate into the water column and the processes of decay of organic residues prevail over oxidative processes. Sometimes hydrogen sulfide zones can form quite extensive accumulations. For example, the rift zone, discovered in 1977 in the zone of the underwater ridge of the Pacific Ocean, south of the Galapagos Islands, is also in in large numbers contains hydrogen sulfide; there are hydrogen sulfide zones in some deep closed bays.

One of the theories of the origin of hydrogen sulfide (the so-called "geological theory") suggests that hydrogen sulfide is released during underwater volcanic activity, and it can enter the seas through tectonic faults in the earth's crust. Hydrogen sulfide lakes in Kamchatka can serve as proof of this theory. Another theory - biological - says that we owe the production of hydrogen sulfide to bacteria, which, processing organic remains that have fallen to the bottom of the sea, form a substance from soil salts (sulphates), which, when combined with sea ​​water forms hydrogen sulfide.

However, one should not think that hydrogen sulfide is stored in the seas as Chemical substance in a warehouse, sealed in boxes. The sea is a constantly working biochemical laboratory. Thanks to the work of bacteria, plants and animals, some elements in the sea are constantly transformed into others. Ecological chains are formed in which a balance is maintained that determines the integrity of the entire structure. Bacteria play a huge role in the decomposition of organic remains into forms consumed by plants. Some bacteria can live without oxygen and light (anaerobic bacteria), others need sunlight to live, and others process organic compounds using both light and oxygen. Getting into different layers of the sea, organic matter falls on the corresponding cycle of its processing and, in the end, the cycle closes - the system returns to its original state.

Therefore, when the layers of the sea move (mixing), hydrogen sulfide is gradually converted into other compounds. In the Black Sea, water is mixed very weakly. The reason for this is the sharp changes in salinity, separating sea water, as in a glass of cocktail, into separate layers. main reason the appearance of such layers is the insufficient connection of the sea with the ocean. The Black Sea is connected to it by two narrow straits - the Bosphorus, leading to the Sea of ​​Marmara, and the Dardanelles, which maintains contact with the rather salty Mediterranean Sea. Such isolation leads to the fact that the salinity of the Black Sea does not exceed 16-18 ppm (a value equal to the salt content in human blood), while the salinity of normal ocean water should be in the range of 33-38 ppm (the Sea of ​​Marmara, having an intermediate salinity of about 26 ppm, acts as a kind of buffer that prevents the highly saline waters of the Mediterranean from flowing directly into the Black Sea). Salt water from the Sea of ​​Marmara, as a heavier one, when meeting with the waters of the Black Sea, sinks to the bottom and enters its lower layers in the form of an undercurrent. In the boundary layer region, not only abrupt change salinity - "halocline", but also a sharp change in water density - "pinocline" and temperature - "thermocline" (deeper, denser layers of water always have a constant temperature - 8-9 degrees above zero). Such heterogeneous layers make our sea cocktail a real layered cake, and, of course, it becomes very difficult to “mix” it. So, in order for water from the surface of the water to reach the bottom of the sea, hundreds of years are needed. All these factors lead to the fact that hydrogen sulfide, constantly accumulating in the depths of the Black Sea, gradually formed a vast lifeless zone.

Unfortunately, huge quantities of fertilizers and untreated sewage have been dumped into the sea lately, causing a glut. growth medium Black Sea. This was the reason for the rapid flowering of phytoplankton and the decrease in water transparency. The insufficiency of solar energy supply, necessary for the respiration of plants, led to the mass death of algae, and, along with them, of many living beings. Underwater forests gave way to thickets of primitive, fast-growing sea grass (filamentous and lamellar algae). Organic remains, not processed by bacteria, fall to the seabed in countless quantities. There is a mass death of flora and fauna.

In 2003, a unique accumulation of the red algae phyllophora (Zernov's phyllophora field), with an area of ​​11 thousand square meters, was completely destroyed. km., which occupied almost the entire part of the northwestern shelf of the Black Sea. This "green belt" of the sea produced about 2 million cubic meters. m of oxygen per day and, of course, with its destruction, the kingdom of hydrogen sulfide has lost one of its main competitors in the struggle for natural resources - oxygen that oxidizes it.

The high rate of death of algae and sea grass, the mass death of living beings, the decrease in the level of oxygen in the water - all these factors inexorably lead to the accumulation of a huge amount of decaying residues in the depths of the Black Sea and to an increase in the amount of hydrogen sulfide in the water.

So far, we are not afraid of hydrogen sulfide, since in order for the gas bubble to come to the surface, its concentration is needed, which is 1000 times higher than the existing level. However, you should not relax. Too many factors speed up this process. Among them: the construction of breakwaters that reduce the rate of water circulation, work to deepen the seabed, laying oil pipelines, discharging fertilizers and sewage into the sea, and mining. Human activity is of such magnitude that no ecosystem can withstand it. What threatens us?

Studying the archaeological layers, scientists have discovered amazing fact almost instantaneous disappearance of the vast majority of life forms in the Permian period. One of the theories explaining such a catastrophe states that the massive death of fauna and flora was due to an explosion of a poisonous gas, presumably hydrogen sulfide, which could have been formed both due to numerous eruptions of underwater volcanoes, and as a result of the activity of hydrogen sulfide-producing bacteria. Research by Lee Kamp from the University of Pennsylvania, USA, showed that a decrease in the concentration of oxygen in the sea provokes an increased reproduction of bacteria that produce hydrogen sulfide. When a critical concentration is reached, this process can lead to the release of toxic gas into the atmosphere. Of course, it is too early to talk about any specific conclusions, the dynamics of changes in hydrogen sulfide levels is not exactly clear yet (it may take about 10 years to conduct a comprehensive analysis), but in the facts presented, one cannot help but feel hidden threat. Nature has always been too patient with us. Can we expect salvation from her this time too?

4. Well, about hydrogen sulfide as a source of energy, one more thing:

The advantages of hydrogen as a fuel over gasoline are summarized as follows:

Inexhaustibility. The total mass of hydrogen atoms is 1% of the total mass of the Earth;
Environmental friendliness. When burned, hydrogen turns into water and returns to the Earth's cycle. The greenhouse effect is not enhanced, there are no emissions of harmful substances during combustion;
The weight calorific value of hydrogen is 2.8 times higher than that of gasoline;
The ignition energy is 15 times lower than that of gasoline, the flame radiation during combustion is 10 times less.
It would be possible to store the resulting hydrogen with the help of an energy storage substance. This topic is well developed in theory. There are many different EAVs. Such a substance (for example, wood) is created (emerges) under the influence of energy (solar), and then, as a result of oxidation (combustion), it gives off this energy (heat). Another example of such a substance is silicon. Only, unlike wood, it can be restored from oxide (the so-called "Varshavsky-Chudakov cycle").

So, according to scientists, there is a real opportunity to extract and accumulate hydrogen from the Black Sea hydrogen sulfide with its subsequent use in the energy sector. True, the energy system of the country is completely unprepared to take advantage of this opportunity at the current stage. Meanwhile, the situation with conventional fuels is becoming increasingly threatening. Hydrogen could become an alternative to gasoline.

And some more numbers. One ton of hydrogen sulfide contains 58 kg of hydrogen. When burning 58 kg of hydrogen, the same amount of energy is released as when burning 222 liters of gasoline. The Black Sea contains at least a billion tons of hydrogen sulfide, which is equivalent to 222 billion liters of gasoline.

5 . Well, a little history and, again, some theories,

The information in the articles is repeated in places, I just chose the most interesting of them.

Over the past 60 years, almost 40% of the Black Sea area has become uninhabitable. This is the conclusion made by Belgian scientists from the University of Liege. According to experts, from 1955 to 2015, the depth of oxygen penetration decreased from 140 to 90 meters. At the same time, scientists discovered a deterioration in water quality associated with a large influx of phosphorus and nitrogen compounds into the sea.

That the water has become worse can be seen with the naked eye. Many vacationers complain that not only in Sochi, where the water has always been not very good, but in Abkhazia it is now dirty. Even on the beaches they warn that it is still possible to swim, but God forbid you take a sip of sea water - you can catch an infection. This, of course, upsets tourists: what kind of vacation at sea without diving?

Fishermen note a significant decrease in catch. Moreover, fishermen complain not only from Odessa and the Crimea, but also from Bulgaria and Georgia.

However, now it turns out that the Black Sea is threatened by a much more serious danger than E. coli or a decline in the fish population.

“People watched in horror as the ashen sea began to seethe, boil, turn into a truly black one, as they called it God knows from what perelyaku, and began to disappear into some kind of funnel. It smelled disgustingly of hydrogen sulfide. The Black Sea ceased to exist ... Later, commenting on the incredible event, scientists came to the conclusion that few people always worried about the fatal role of hydrogen sulfide, which lies in a layer at a depth of forty meters, now it has escaped to the surface and “ate” the water. So the writer described the ecological catastrophe in the political novel "Nabat" Alexander Gera.

How can it really be?

It is known that the Black Sea has a depth of up to two thousand meters. But at a depth of more than 200 meters, only bacteria that produce hydrogen sulfide live. Fish and other organisms cannot live, since there is no oxygen there, there is only “dead water”, that is, a combination of hydrogen and sulfur. The surface layer is predominantly of river origin, the salt level there is quite low for the sea. At a depth of 50 to 100 meters, the salt content increases dramatically. The upper layers are much lighter than the lower ones, so they hardly mix.

Thus, the Black Sea is a deep reservoir with hydrogen sulfide and a thin layer of almost fresh water, where all living organisms live. If this thin layer is threatened with extinction, then the entire sea can become not only lifeless, but also explosive.

Senior agrees with these assessments. Researcher Sevastopol branch of the State Oceanographic Institute named after N.N. Zubova Anatoly Ryabinin. He believes that a big catastrophe could threaten the Black Sea:

“According to our research, over the last decades of the last century, the layer of hydrogen sulfide water really rose, sometimes to the level of 75 meters. In 1986, a special commission worked, it established that the danger of rising hydrogen sulfide waters remains.

"SP": - These studies have been carried out for a long time. What is the picture now?

- Unfortunately, all the information we have is only for the last century. In this century, we did not measure anything, we were not allocated money for research. In Soviet times, I was in charge of the laboratory of marine chemistry, so I was punished if by the end of the year I did not have time to spend all the funds allocated to the laboratory.

Our studies have shown that the level of hydrogen sulfide is increasing and we can expect emissions of hydrogen sulfide into the atmosphere during some cataclysms.

One simple fact can testify to the importance of the study of the Black Sea. Once a major of state security came to me and consulted. As he told me, the KGB had information that the Americans could lay a nuclear charge on the bottom of the sea and, in case of war, blow it up. We were then asked to evaluate the consequences of the explosion.

"SP": - And nothing can be done about this hydrogen sulfide scourge?

- At one time, the possibility of extracting hydrogen sulfide was studied in order to use it as a fuel. Employees of the Moscow Research Institute of Oceanology. PP. Shirshov RAS always advocated not to extract more hydrogen sulfide than it is produced, as this can upset the natural balance. I have always taken a different point of view. In my opinion, hydrogen sulfide must be extracted in large quantities in order to clean up the sea over time, say, in a hundred years. Today, the Black Sea is the most dangerous on the planet.

"SP": - What are the consequences of raising the level of hydrogen sulfide?

— To the most catastrophic. In 1927, an earthquake occurred near Yalta. Then the sea literally burned. Some scientists believe that it was burning hydrogen sulfide.

If we talk about the factors that affect the level of danger, we can include natural and human impact. Today, objectively, the sea is polluted, this is a fact. I do not really believe in global warming, but it is difficult to say with complete certainty what consequences to expect.

In general, according to some scientific data, about 6000 years ago the Black Sea was clean, there was no hydrogen sulfide in it. For geology, this is a very short time. That is, the accumulation of hydrogen sulfide is rapidly.

A different point of view is shared by the head of the department of the Azov-Black Sea basin and the World Ocean of the Southern Research Institute fisheries and oceanography (city of Kerch) Vladislav Shlyakhov:

- In the Black Sea, there really is an extensive layer of hydrogen sulfide water, which is located at different depths in different parts sea, from 90 to 150 meters. The level of the hydrogen sulfide layer constantly pulsates, then rises, then decreases. It is not yet clear what data the Belgian scientists rely on. I personally do not see anything catastrophic in the change in the level of hydrogen sulfide.

There was a big noise back in the 1980s, when our institute, then employees of the Research Institute of Oceanology. Shirshov discovered an increase in the level of hydrogen sulfide. But further observations showed that this a natural phenomenon. The rise is followed by a decline.

There is an opinion among some experts that sooner or later a catastrophe will happen. But in my opinion, there are normal fluctuations.

Over the past few years, the amount of precipitation has decreased, and accordingly, freshwater runoff has decreased. As a result, the level of hydrogen sulfide increased. All these processes have a large amplitude. Let's say in next years there will be more precipitation, and the freshwater layer will increase, hydrogen sulfide will decrease.

"SP": - How does global climate change affect the process of changing the level of hydrogen sulfide?

- The climate is really changing, there is no reason to deny it. In the Black Sea, this is manifested in the fact that more warm winters lead to a change in the productivity of fish and other living organisms. But this has nothing to do with hydrogen sulfide. There will be more fresh water, and the level of hydrogen sulfide will decrease. There is a "locking layer" that prevents the penetration of hydrogen sulfide to the surface.

"SP": - How does economic activity affect the level of hydrogen sulfide?

— Economic activity will affect in one case. If the withdrawal of freshwater runoff increases. Let's say that water used to come to us through the North Crimean Canal from Ukraine. The flow of fresh water going to the Black Sea was decreasing. Because a lot water resources used for irrigation of fields and household needs. Now, flooding has begun near the Kakhovskaya hydroelectric power station in Ukraine, and Ukrainians are forced to dump excess water. They don't supply us with water anymore. As they say, neither to themselves nor to people. So, they throw excess water into the sea. Thus, the flow of fresh water into the sea has increased. In the northwestern part of the sea, even desalination is observed.

"SP": - The water in the sea has become dirtier, all sorts of infections have appeared.

- This is due to anomalous warm summer. The sea began to warm up earlier, the high water temperature persisted longer. Plus domestic and industrial drains. By the way, there are fewer stocks compared to Soviet times.

"SP": - Does climate change somehow affect the ecology of the Black Sea?

- This factor, of course, affects. And not only to the Black Sea - to all the seas. With global warming, we can face much bigger problems than rising levels of hydrogen sulfide. We see that glaciers are melting in Antarctica, near Greenland. The rise in the level of the World Ocean is much more dangerous, since the balance existing in nature can be disturbed.

But if we talk about a perspective commensurate with the lives of our children, then disasters should not come. However, my opinion is one of many.

The surface layer of the Black Sea water - down to a depth of about 100 meters - is predominantly of riverine origin. At the same time, more salty (heavier than fresh) water from the Sea of ​​Marmara enters the depths of the sea - it flows along the bottom of the Bosphorus Strait (lower Bosphorus current) and sinks deeper. Therefore, the salinity of the bottom layers is higher.

Two masses of surface water are formed with a lower salt content - lighter and closer in temperature to air (in summer it is warmer than deep waters, and colder in winter), and deep - more salty and heavy, with a constant temperature.

The change in the properties of water with depth is not smooth. From the surface up to 50-100 meters salinity changes rapidly, and to the bottom it increases evenly. The density of water also changes with salinity.

Hydrogen sulfide is one of the most mysterious properties in Black Sea. At a depth of about 150 to 200 meters - there is no oxygen in the Black Sea water - neither animals nor plants can live there. At depths from 200 meters to the very bottom of the Black Sea, only bacteria that emit hydrogen sulfide live.

The sea surface temperature is always determined by the air temperature. And the temperature of the deep waters of the Black Sea - all year round+7+8 degrees Celsius.

A layer of water from 50 to 100 meters is called a boundary layer - this is the boundary between two masses of Black Sea water, the boundary that prevents mixing is always colder than deep waters, since, cooling down to + 5 + 6 degrees Celsius in winter, it does not have time to warm up over the summer.

Stratification - the stratification of Black Sea water by salinity, density and temperature - prevents the vertical mixing of the sea and the enrichment of the depths with oxygen.

The farther from the sea surface, the less oxygen remains in the water. In the aphotic zone of the sea (where sunlight does not penetrate), under the cold intermediate layer - below 100 meters deep, oxygen is no longer formed, only consumed.

There is enough oxygen for the life of animals and plants only in the upper 150 meters Black Sea. Its concentration decreases with depth, the bulk of life in the sea is concentrated above 100 meters deep.

Below 200 meters there is no oxygen, only anaerobic bacteria live there, decomposing the remains of the living, sinking from the upper layer of the sea.

90% water mass Black Sea- are almost lifeless, but in any other sea or ocean, all life is concentrated in the upper, 100-200-meter layer of water.
In summer, especially near the coast, a changeable summer thermocline is formed - the boundary between the surface water warmed by the sun, in which people bathe, and cold deep water. The thermocline drops as the water warms up in summer, sometimes reaching depths of more than 40 meters in August.
Summer thermocline is a thin layer of water, from several centimeters to several meters thick; often - it is clearly visible under water, and very well felt by divers - diving a few meters in the direction of the bottom, you can get from 20-degree to 12-degree water. The thermocline is easily destroyed by a storm or a strong offshore wind.

The bottom relief of the Black Sea

Black Sea- deep, the central part of its bottom is occupied by a silty abyssal (deep) plain lying at a depth of two kilometers, and the slopes of the Black Sea basin are steep. Max Depth Black Sea- 2210 m.

Shelf Black Sea- a gentle underwater slope, the continuation of the coast under water to a depth of 100-150m - near the mountainous coasts (Caucasus, Crimea, Anatolia) - no more than a few kilometers from the coastline. Further - a very steep (20-30 degrees) continental slope follows - a cliff to depths of more than 1000 meters. The exception is the shallow Northwestern part Black Sea- it all belongs to the shelf zone, and, in fact, is not part of the Black Sea basin.

Such a bottom topography contributes little to the intensive exchange of water between the depths of the sea and its surface, since the surface of the sea turns out to be small relative to its volume. The smaller the surface of the sea for a given volume, the less oxygen per unit volume of the sea enters the sea from the air and is created by algae in the illuminated water layer. Therefore - and the shape of the cavity Black Sea does not favor the enrichment of its depths with oxygen.

Bottom sediments Black Sea: no matter what the shores and beaches are - sandy, pebbly, or rocky - starting from a depth of 25-50 meters, at the bottom Black Sea- sand or gravel. With increasing depth, the surface is covered by fragments of mussel valves, and even deeper - by the modiolus Modiolus phaseolinus, which form the phaseolin silt of the shelf. The thickness of the accumulated sediments on the abyssal plain is from 20 to 80 centimeters in different parts of the bottom.