Deep secrets of the Black Sea. An explosion of hydrogen sulfide is possible in the depths of the Black Sea. The lad warned. Black Sea Map of the depths of the Black Sea detailed in the bays

Considering relief the Black Sea bottom, we can distinguish:

• shelf;
• extended continental slope;
• deep basin.

The widest part of the shelf (about 200 km) is located in the northwest of the Black Sea. The thickness of the water layer here is 110 - 160 meters. The depth of water above the shelf in other places of the sea is less and, as a rule, does not exceed 110 m. The width is from 10 to 15 km (near the Turkish coast - 2.5 km).

The continental slope is heterogeneous, heavily dissected by underwater valleys and canyons. Its steepness in some areas reaches 20-30°. From Sinop to Samsun, a system of deep ridges stretches almost parallel to the coast. Their total length is about 150 km. The bottom of the basin is an accumulative plain, deepening flat to the center up to 2000 m. depth of the Black Sea- 2211 m.

The bottom of the sea consists of parts of different ages and geologically heterogeneous. A larger section of the basin is located in the Alpine geosynclinal region. The earth's crust below it consists of many layers, which can be roughly divided into "sedimentary" and "basalt". Sedimentary layers are about 16 km thick, and their upper, 4 km, part is located horizontally. In the central section of the basin, the density of the earth's crust reaches 25 km. On the periphery, the basalt layer is hidden under a 35-kilometer granite layer. The northwestern section of the Black Sea shelf captures the epipaleozoic Scythian platform and the south of the East European platform.

coastal zone Black Sea- These are coarse-grained deposits, such as pebbles, gravel and sands. With distance from the coast, these deposits are replaced by silts and fine-grained sands. In the northwestern region of the Black Sea, there is an abundant formation of shell rock and jars inhabited by oysters, mussels and other mollusks.

In the Black Sea there are deposits of minerals - oil and gas. Their main reserves are concentrated in the northwestern part of the basin. In addition, the coastal zones of Taman and the Caucasus can boast placers of titanomagnetite sands.

The territory of the modern Black Sea has a complex geological past. Even today, scientists are discovering traces of various natural disasters under calm sea waves.

Forty million years ago, at the beginning of the Tertiary period, Asia and southern Europe were the bottom huge ocean basin called the Tethys Sea. With a giant canal, this sea connected the Atlantic Ocean with the Pacific. In the middle of the Tertiary period, movements of the earth's crust separated Tethys from the Pacific Ocean, and then from the Atlantic.

Active mountain-building movements in Eurasia began about seven million years ago, during the Miocene period. Formed over four million years Carpathians, Alps, Balkans and the Caucasus Mountains. The area of ​​the Tethys Sea decreased, separate basins were formed from it. One of these basins was the Sarmatian Sea, stretching from the foothills of the Tien Shan to modern Vienna.

At the beginning of the Pliocene period (1.5 - 3 million years ago), the Sarmatian Sea decreased in size, first becoming salty Meotic Sea, and later - almost fresh Pontic lake-sea. One million years ago, the size of this lake was comparable to the size of Chaudinsky Lake.

Approximately 500 thousand years ago, the Mindel glaciation ended. The glaciers began to melt. Their waters flowed in streams into Lake Chaudinsky, filling it and turning it into Ancient Euxinian Basin. Its area was close to that of the modern Black Sea.

150 thousand years ago, the Karangat Sea formed from the Ancient Euxinian basin. The salinity of the water in it was much higher than the salinity of the water in the Black Sea of ​​our days.

20 thousand years ago, the Karangat Sea slowly "turned" into the Novoevksinskoe Sea. Its appearance coincided with the end of the last Wurm icing. The transformation of the Novoeksinsky Sea lasted 10 thousand years, after which a new, modern stage in the life of the Black Sea began. And at this stage, we, people, are strenuously helping nature to "accelerate" the course of the Black Sea history...

This sea is perhaps closest to us. Once it was called "Russian" - these are echoes of the Soviet era, when the Black Sea was the most "popular". Today, the sea washes the shores of seven countries: Russia, Ukraine, Bulgaria, Romania, Turkey, Georgia and Abkhazia.

Hospitable or inhospitable?

The Black Sea had a huge number of names. The very first, which has come down to our days, was given to him by the ancient Greeks. By the way, it was along the Black Sea that Jason and the Argonauts set sail for the Golden Fleece.

The Greeks called it Pont Aksinsky, which means "inhospitable sea." And all because it was not so easy to approach it: the shores of the Black Sea in those days were inhabited by warring tribes, zealously guarding the territory. Yes, and navigation on the reservoir was quite difficult. Later, after the conquest and development of its coast, the sea became "hospitable" or Pontus Eusinsky. In addition, his other names are also known: Temarun, Akhshaena, Cimmerian, Blue, Ocean, Tauride, Holy, Surozh. Well, in Russia, the Black Sea was called the "Scythian" or "Russian" from the 10th to the 16th century.

why black

In fact, there is no exact explanation why the reservoir was nicknamed "black". There are at least two versions of origin.

In the old days, parts of the world were designated by colors: black meant the North, and white meant the south. According to this theory, the reservoir located in the north was called the "Black Sea". By the way, the Mediterranean Sea in Turkish is known as the "White Sea", that is, the sea that is located in the south.

Well, the second version says that the reservoir got its name because of the abundance of hydrogen sulfide in its depths, which has an unusual property. The fact is that any metal object (for example, an anchor) when lowered into deep waters (more than 150 meters) is covered with a black coating for a long time.

Currents have an unusual shape

The flow pattern of the Black Sea is unusual: these are two ringed whirlpools resembling glasses. True, they are gigantic: the length of their waves reaches about 300-400 kilometers. By the way, they are called so - Knipovich glasses - in honor of the oceanologist who first described them.

About the sea depths of the Black Sea

The maximum depth of the Black Sea is 2210 meters. The average depth is 1240 meters. The deepest places (and not only the deepest in fact) have their own peculiarity: there is no life here. For this feature, the reservoir even received a different name, ominous - "the sea of ​​\u200b\u200bdead depths."

And the thing is that once on the site of the Black Sea there was a freshwater lake. True, a very long time ago: about 7500 years ago. It was inhabited by freshwater inhabitants. And it was the deepest freshwater lake on Earth.

But then cataclysms occurred: perhaps, due to the ice age, the level of the world's oceans rose significantly, flooding the lake and turning it into a sea (the reservoir increased by about one and a half times!), Or an earthquake contributed to the breakthrough of water. Or maybe both natural disasters happened at once. Because of this, many freshwater inhabitants died, infecting the waters with hydrogen sulfide. And hydrogen sulfide is nothing more than a product of the vital activity of bacteria, or rather, a product of the decomposition of the remains of animal organisms.

Well, we see the result today: at a depth of more than 150-200 meters in the Black Sea, there is practically no life. There are only bacteria here.

By the way, perhaps this tragedy served as the basis for the Flood. After all, it was distributed locally, especially among the peoples of the Middle East.

Sharks that can cure cancer

Despite the contamination with hydrogen sulfide, the Black Sea has its own inhabitants, and very interesting ones.

So, harmless katrans sharks are found here. They are small, do not exceed a meter in length, and do not pose a danger to vacationers: they practically do not approach the shore and live mainly in cold waters, and they are afraid of people.

However, they can pose some threat to fishermen. The fact is that on their dorsal fin there are large spikes that can hurt.

And sharks-katrans are used in pharmacology. Their fat has healing properties, and a substance found in their liver can cure some forms of cancer. Therefore, on its basis, a drug was developed to combat tumors "Katrex".

Other inhabitants of the Black Sea

In addition to small sharks, about 2,500 other species of animals live in the Black Sea. But this is very small: for example, in the Mediterranean there are about 9 thousand species of animals.

The most dangerous of the Black Sea inhabitants is a large sea dragon or sea dragon. It has poisonous spines on its dorsal fin. And this is the most poisonous fish that lives off the coast of Europe. The dragon's bite is very painful, and several deaths have even been reported. But besides him, there are two more dangerous inhabitants: the Black Sea scorpionfish and the stingray.

Of the mammals in the Black Sea, two species of dolphins live, the white-bellied seal and the porpoise. Some animals enter the reservoir through the Bosphorus.

Well, among the algae there is a very unusual species - a sea candle. This algae is capable of bioluminescence: their accumulation at the surface of the water causes an interesting phenomenon - the glow of the sea. It can be seen in August.

The Black Sea is a deep-water basin with relatively steep slopes. The profile, that is, the vertical section of the Black Sea, is shown in the figure. When considering this profile, it should be taken into account that for greater clarity of the image, the vertical scale is taken much larger than the horizontal one, so the bottom profile turned out to be steep, but in reality the bottom is not inclined as much as shown in the figure.

Many people think that in the Black Sea, immediately from the coast, a sharp lowering of the bottom begins, and where gliders and boats are clearly visible from the beach (about 500-1000 meters from the coast), the depths are already measured hundreds of meters. Meanwhile, this is far from being the case. The line of 100-meter depths runs at a distance of 200 kilometers from the coast in the northwestern part of the sea, 10-15 kilometers - in the main part and only in certain areas (Crimea) - at a distance of one kilometer. The bed of the sea is mostly flat, but there are small cracks and ledges, there are also hills with very gentle slopes.

The greatest depth of the Black Sea is 2211 meters. The region of maximum depths is located in the central part of the sea, somewhat closer to the Turkish coast.

At the bottom of the Black Sea, in one of its deepest depressions, the so-called Yalta, at a depth of over 2 kilometers, a man visited, the first dive in the last century (1971) on a special deep-sea submersible "North-2". Its length is 4 meters, the displacement is 15 tons. The device had a crew of 4 people under the leadership and with the participation of M. N. Diomidov, a well-known Soviet designer of deep-sea vehicles.

What do aquanauts see when diving into the depths of the Black Sea? Only in the surface layer - up to 100 meters there is life. Deeper in complete darkness, under the beams of a searchlight, only organic remains glow, slowly sinking to the bottom and resembling snow flakes. But here you can also meet human creations - sunken ships of various eras rest in the darkness of the depths.

There are two types of structure of the earth's crust - oceanic and continental. In the ocean, under a layer of water, there is a layer of sediments that gradually accumulate there, the thickness of this layer is from 2 to 5 kilometers. Then comes the basalt layer of the same thickness and, finally, magma, which comes to the surface during volcanic eruptions. Under the continents there is no sedimentary layer, but the basalt layer is thicker there, up to 20 kilometers, and, in addition, there is another layer - granite, 10-15 kilometers thick, located above the basalt one.

Under the Black Sea, the structure of the earth's crust resembles that of the ocean, but the layer of sedimentary rocks there is more than 10 kilometers, that is, thicker than in the ocean, and the basalt layer has a thickness of 10-20 kilometers (less than under the continents, but more than under the oceans). The granite layer passes only near the coast.

Since it is known that the Black Sea is geologically young, the structure of the earth's crust under it allows us to confirm one of the opposite assumptions about the formation of continents and oceans. Some scientists believe that the oceans were formed before the continents, that the primary type of the earth's crust was basalt, so these rocks are shallow in the ocean. Then granitic magma flowed through the cracks, which formed the continents. Other scholars take the opposite view. They believe that the seas are more modern than the continents. This point of view is confirmed by the oceanic structure of the bottom of the "young" Black Sea. If the continents were younger than the oceans, then under the Black Sea, as well as under other inland seas, there would be a large layer of granites.

Now, having been under the bottom of the Black Sea, we will rise above and get acquainted with the composition of the soils covering its bottom from above. The soils of the Black Sea were formed as a result of the interaction of three main factors: the destruction of the coast, the removal of rivers and the deposition of organic residues. Coastal soils consist of pebbles, gravel, sand, silt (very small particles). The bottom at a depth of 20 to 150 meters is covered with silts with shells of mussels and phaseolins. Deep-sea silts are clayey and calcareous. The bottom at a depth of 200 to 1500 meters is covered with dark (gray, brown, brown) silts.

Having been at the bottom of the sea, we will rise even higher and get acquainted with the relief of the bottom near the coast of the sea. Before giving a general description of the coastal sections of the Black Sea bottom, it is necessary to dwell on the enormous role that waves play in their change. The figure shows the dotted line, what was the original profile of the coast. Sea waves cut off part of it, forming a steep ledge, or cliff, while the soil sank down the slope, creating deposits here, and part of the soil moved along the coast under the influence of the waves. Thus, the destructive and creative activity of waves in the surf zone exists simultaneously.

Let us now turn to the characterization of the bottom of individual regions of the Black Sea.

bottom characteristics

The shores of the northwestern part are shallow, on the western coast of Crimea there are also extensive sandy beaches. Near the southern coast of Crimea, the beaches are small, since the rocks there are made of very strong rocks that even the thousand-year work of the sea could not destroy. For example, the rock "Monk" stood near Simeiz for several centuries, and only in 1927 it was destroyed by an earthquake.

An interesting feature of the Caucasian coast are huge ledges, for example, near the Pitsunda and Sukhumi capes. Their base lies at a depth of up to 200 meters. They were formed in the process of accumulation of soil, which is carried out by rivers into the sea, and then moves along the coast under the action of waves. Approaching the ledges, sediments fall into the sea, gradually building up capes. A feature of the Caucasian and Anatolian coasts of the sea is the presence of submerged delta ledges of rivers that form underwater shallows, such as Gudautskaya.

An equally interesting feature is the canyons - deep valleys with relatively steep slopes that run from the coast to the sea and along its bottom. The canyons are located opposite the mouths of the Colchis rivers - Inguri, Khobi and Rioni. The slope of their slopes sometimes reaches 25 degrees (400 m / km), and the longitudinal slope of 12 degrees (200 m / km). The canyons extend to a depth of 1000 meters. Scientists from many countries are working to elucidate the mystery of the origin of canyons (there are such landforms near California and against the mouths of African rivers).

Perhaps these are the hollows of the rivers flowing here, which were flooded during the rise in the level of the World Ocean (by hundreds of meters), caused by the melting of ice after the last glaciation. Perhaps canyons are cracks in the earth's crust formed during earthquakes. Maybe the canyons were formed as a result of erosion of the bottom by artesian sources.

Hydrogen sulfide in the Black Sea - one of the most famous and unusual properties of the sea. But - an excess of hydrogen sulfide in the deep waters of the Black Sea - is only one of the consequences of the fact that deeper than 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. There is no other sea like it in the world.
It turns out like this:

Oxygen penetrates into the water through the surface of the sea - from the air; and more - is formed in the upper illuminated layer of water (photic zone) when photosynthesis of plankton algae.

In order for oxygen to get into the depths, the sea must be mixed - due to waves and vertical currents. And in the Black Sea - the water is mixed very weakly; it takes hundreds of years for water from the surface to reach the bottom. The reasons for this unusual phenomenon are as follows:

In the Black Sea, due to its desalination by rivers, there are two masses, two layers of water, which weakly mix with each other.

The surface layer of the Black Sea water - down to a depth of about 100 meters - is predominantly of river origin. At the same time, more salty (and therefore heavier) 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 of the Black Sea water reaches 30‰ (a gram of salt per liter of water).

Changes in water properties with depth - not smooth: from the surface to 50-100 meters salinity changes quickly - from 17 to 21 ‰, and already further - to the bottom - it increases evenly. In accordance with salinity changes and density of water.

Temperature on the sea surface is always determined by the air temperature. And the temperature of the deep waters of the Black Sea is 8-9 ° C all year round. From the surface to a depth of 50-100 meters, the temperature, like salinity, changes quickly - and then remains constant until the very bottom.

These are the two masses of the Black Sea water: superficial- desalinated, lighter and close in temperature to air (in summer it is warmer than deep waters, and in winter it is colder); and deep- more salty and heavy, with a constant temperature.

A layer of water from 50 to 100 meters is called the boundary- this is the border between the two masses of the Black Sea water, the border that prevents mixing. Its more accurate name is cold boundary layer: it is always colder than deep waters, because, cooling down to 5-6 o C in winter, it does not have time to warm up over the summer.

The layer of water in which its temperature changes drastically is called thermocline; layer of rapid salinity change - halocline, water density - pycnocline. All these sharp changes in the properties of water in the Black Sea are concentrated in the area of ​​the boundary layer.

Bundle - stratification of the Black Sea water salinity, density and temperature - prevents vertical mixing of the sea and enrichment of the depths with oxygen. In addition, all the rapidly developing Black Sea life breathes - planktonic crustaceans breathe, jellyfish, crabs, fish, dolphins, even the algae themselves breathe - they consume oxygen.

When living organisms die, their remains become food for saprotrophic bacteria. Bacterial decomposition of dead organic matter (rotting) uses oxygen. With depth, decomposition begins to prevail over the processes of creating living matter by planktonic algae, and oxygen consumption during respiration and decay becomes more intense than its production during photosynthesis. Therefore, 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 a 100-meter depth, oxygen is no longer produced, but only consumed; it does not penetrate here due to mixing - this is prevented by the stratification of waters.

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

In the depths of the Black Sea, below 200 meters, there is no oxygen at all, and only anaerobic saprotrophic bacteria live there, continuing the decomposition of the remains of the living, sinking from the upper layer of the sea. During anaerobic (oxygen-free) decomposition of the remains, hydrogen sulfide is formed - a substance that is toxic to both animals and plants (it blocks the respiratory chain of mitochondria). The source of sulfur is the sulfur-containing amino acids of proteins, and to a lesser extent, the sulfates of sea water, which are used by some types of bacteria to oxidize organic matter.

And so it turns out that 90% of the water mass of the Black Sea is almost lifeless. But after all, in any other sea or ocean, almost all life is concentrated in the upper, 100-200-meter layer of water - just like here. True, due to the lack of oxygen and the presence of hydrogen sulfide in the water, there is no deep-sea fauna in the Black Sea. , this reduces its biodiversity even more, in addition to the impact of low salinity. For example, there are no predatory fish of the depths with huge toothy mouths, in front of which luminous baits are hung.

Sometimes they say that hydrogen sulfide appeared in the Black Sea due to its pollution, that hydrogen sulfide is becoming more and more, that the sea is on the verge of disaster ... Indeed, overfertilization is the eutrophication of the Black Sea with runoff from agricultural fields in the 1970-80s, caused the rapid growth of "weedy" marine vegetation - some types of phytoplankton, filamentous algae - "mud", more organic remains began to form, from which hydrogen sulfide is formed during decay (more on this at the end of the page Changes in the Black Sea ecosystem). But this "extra" hydrogen sulfide did not introduce significant changes into the balance that has developed over the millennia. And for sure - there is no danger of an explosion of hydrogen sulfide - in order for a gas bubble to form, the concentration of molecules of this substance in water must be orders of magnitude greater than the real one (8-10 mg / l at depths of 1000-2000m) - check using formulas from school chemistry courses and physics.

In summer, especially near the coast, a variable summer thermocline- the boundary between the surface water warmed by the sun, in which people bathe, and the 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 summer coastal thermocline is easily destroyed by a storm or strong wind from the coast - the water near the coast cools.

The bottom relief of the Black Sea . The Black Sea is deep; the central part of its bottom is occupied by a muddy abyssal (i.e., deep) plain lying at a depth of two kilometers, and the slopes of the Black Sea basin are steep. The maximum depth of the Black Sea is 2210 m.

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

Such a bottom relief also 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, the shape of the Black Sea basin does not favor the enrichment of its depths with oxygen.

Bottom sediments of the Black Sea: Whatever the shores and beaches - sandy, pebbly, or rocky - starting from a depth of 25-50 meters, at the bottom of the Black Sea - sand or gravel. With increasing depth, the surface is covered with fragments of mussel valves, and even deeper - modiol Modiolus phaseolinus, which form the phaseolin silt of the shelf.

The data of geological studies of the bottom of the Black Sea indicate that sediment layer thickness accumulated on the abyssal plain for the entire the history of the Black Sea - from 8 to 16 km; that is, the depth of precipitation is 4-8 times the depth of the Black Sea water column. The thickness of the sediment layer is 1.5-2 times greater in the western part of the Black Sea, separated by the central Black Sea meridional uplift - from Anatolia to the Crimea. The thickness of the layer of sediments on the abyssal plain accumulated over the last 3000 years of the history of the modern Black Sea is from 20 to 80 cm in different parts of the bottom.

The sediment layer of the Black Sea lies on a 5-10 km thick basalt slab that covers the Earth's mantle. The Black Sea is characterized by the absence of a continuous intermediate layer of granite between the sediments and the basalt platform; the granite layer is common for continental seas. Elements of the granite layer were found by geologists only in the eastern part of the abyssal plain. Such bottom structure, as in the Black Sea - characteristic of the oceans.

Main Black Sea Current directed counterclockwise along the entire perimeter of the sea, forming two noticeable rings ("Knipovich glasses", named after one of the hydrologists who described these currents). Map of the Black Sea This movement of waters and its direction is based on the acceleration imparted to water by the rotation of the Earth - Coriolis force. However, in such a relatively small area as the Black Sea, the direction and strength of the wind are no less important. Therefore, the Rim Current is very variable, sometimes it becomes poorly distinguishable against the background of currents of a smaller scale, and sometimes the jet velocity of the main Black Sea current reaches 100 cm/s.

In the coastal waters of the Black Sea, eddies of the opposite Rim Current direction are formed - anticyclonic gyres , they are especially pronounced near the Caucasian and Anatolian coasts. Local alongshore currents in the surface layer of water are usually determined by the wind, their direction may change during the day.

A special kind of local flow - traction- is formed near the gently sloping sandy shores during strong sea waves: the water running on the shore does not retreat back evenly, but along the channels formed in the sandy bottom. It is dangerous to get into the jet of such a current - despite the efforts of the swimmer, he can be carried away from the shore; to get out, you have to swim not directly to the shore, but obliquely.

Average level Black Sea increased over the past century 12cm; this change is masked by strong fluctuations in sea level (up to 20 cm during the year) associated with interannual variability in river runoff. Recent satellite altimetry data showed a strong acceleration of the Black Sea level rise: up to 20cm/decade(secular trend) in the central part of the sea. A more conservative estimate is 3-4cm/decade. Many experts attribute this phenomenon to the melting of polar ice as a result of global warming.

Tidal fluctuations The level of the Black Sea does not exceed 10 cm, since the Mediterranean tidal waves are attenuated by the straits, and the size of the Black Sea itself is not large enough for the development of strong tides.

The most noticeable rapid changes in sea level are associated with the action of the wind. Strong sustained wind from the shore creates downstream: the sea moves away from the coast, its level in this place decreases, sometimes up to 30 cm per day. Surface water is replaced by water from the depths. With a steady wind from the sea, the opposite phenomenon is observed - wind surge, sea level rise near the coast.

These are - very briefly - the main properties of the modern Black Sea. But it was not always the way we know it today; geography, hydrology, ecology of the Black Sea have changed many times and very strongly. The Black Sea continues to change even now:

The Black Sea is an amazing work of nature that does not leave indifferent any researcher. It still hides many mysteries in its depths. Many scientists today dream of diving into its mysterious dark waters.

This sea covers an area of ​​​​more than 400 thousand square meters. km and is located between Europe and Asia Minor. It appeared in the VI millennium BC. due to the sudden and sharp rise in the level of the World Ocean, and before that it was just a large fresh lake.

Bottom of the Black Sea

Its seabed is similar in relief to a hat turned down. The Black Sea has a fairly wide shallow water near the coast, which can be explored without hindrance, and a deep, voluminous bottom in the middle, so far little known by scientists.

The largest shallow water is located in the northwestern part of the sea, near Odessa and its surrounding resorts. And in the north and east of the Black Sea coast, the explorer is met by the mountains of the Caucasus and Crimea, hiding slopes deep under water.

What is the depth of the Black Sea?

Scientists have established that the maximum depth of the Black Sea is 2,250 m, and the average depth of the Black Sea is available for research - up to 1,300 m. Its inhabitants, whose life can be actually observed, settle no lower than 100 meters from the water surface.

Further, the bottom of the Black Sea drops sharply down to a depth of at least a kilometer, after which the unknown deep water begins. The problem of his research is the presence of hydrogen sulfide in water, which is dangerous for human life and health.

The bottom relief of the Black Sea

The bottom shelf is a gentle slope located under water to a depth of 100-150 meters. The northwest of the sea belongs to the shallow shelf zone. Then a continental almost sheer cliff begins abruptly to a depth of more than a kilometer.

At the bottom of the Black Sea is sand or rocky gravel. Even lower is the phaseolin silt of the shelf. The thickness of the bottom silt, according to scientists, is 8-16 km, it is many times greater than the maximum depth of the sea itself. This is the structure of the ocean floor.

Where does hydrogen sulfide come from?

Today, there are several scientific hypotheses about how hydrogen sulfide appeared in the sea, and why there is so much of it. Leading version: bottom topography and features of currents contribute to the emergence and active life of anaerobic bacteria living without Q.