Black Sea. Deep secrets of the Black Sea. An explosion of hydrogen sulfide is possible in the depths of the Black Sea.

Hydrogen sulfide in the Black Sea one of the most famous and unusual properties seas. But - an excess of hydrogen sulfide in deep waters Black Sea is just one of the consequences of 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. Reasons for this unusual phenomenon the following:

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 is black sea ​​water- to a depth of about 100 meters - mainly 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 - all year round 8-9 o C. From surface to depth 50-100 meters temperature, like salinity, changes rapidly - 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, the sea (where it does not penetrate sunlight), under a 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, no predatory fish 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 the formulas from school courses chemistry 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 - 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; central part 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 sea surface 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 coast 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 sea level fluctuations (up to 20 cm during the year) associated with the interannual variability of 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 dimensions of the Black Sea itself are 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:

Usually scientists, explaining the presence of a huge mass of hydrogen sulfide in the Black Sea (BS), explain this by the uniqueness of this reservoir. The following arguments are given:

1. The Black Sea is a closed basin, it is connected to the world ocean by narrow straits.


2. Large rivers are dumped in the World Cup a large number of organics.


3. The ChM has a great depth and a sharp drop from the continental shelf to depth.


4. The high salinity of the deep layers of the Black Sea does not allow oxygen to penetrate down and this contributes to the formation and accumulation of hydrogen sulfide.


5. Due to the unique hydrology of the Black Sea, there is no mixing of layers in it.

Looking at this map, we quickly see that the characteristics of the World Cup are not unique.

The depth of the KM is quite decent - 1025 m. At the same time, we observe a significant difference in depths, almost a cliff in the confluence of the Kura River. Yes, and in the middle part of the pool, too. There is no doubt about organics - pollution from oil production is added to the drains of the mighty Volga, Kura and Urals. But there are no deep layers of hydrogen sulfide in the CM! Although the salinity in the southern part of the sea reaches 28 ‰.
There remains one and the last argument of the uniqueness of the FM - the absence of mixing layers. Why do they mix in other seas, but not in the Black Sea? It should be noted that the very method of determining the parameters of sea water, deep currents and salinity is very complicated. The fact is that similar works require significant costs. The operation of oceanographic vessels is fabulously expensive. Where better to spend money on the construction of cruise ships, a kind of floating paradises, then to sink and burn them in order to receive insurance.

In addition, the volume of such studies is extremely large. With great difficulty, we had some idea only about the surface of the oceans and seas, and if we also take their thickness .... this is a colossal amount of information. Often even submarines die due to lack of such knowledge. They fall into the deeper layers with a lower density, as if breaking through the ice of a denser layer. How these layers are formed, where they are located and why - all this is still a mystery to oceanology.
Therefore, it is premature to state with certainty that there is no vertical mixing of layers in the FM for such and such a reason. But it is missing, and this is a fact.
However, hydrogen sulfide is successfully formed in other seas and basins. An accelerated formation of hydrogen sulfide has been noticed, for example, in the Norwegian fjords. Driving by car to Odessa past the estuaries, we are forced to plug our noses and close the windows of the car - it stinks unbearably of hydrogen sulfide. This gas is also formed in other seas and even in lakes.
Not far from the resort of Playa del Carmen is a filled fresh water Cave of Cenote Angelita. Lost in the impenetrable jungle of Mexico, the cave is fraught with many surprises, one of which is an amazing underwater lake! At the bottom of this lake there is also a hydrogen sulfide layer.

From this we can conclude that the ChM is absolutely not a unique basin in this regard, and the presence of 3.1 billion tons of hydrogen sulfide in it is due to other reasons.
Here I would like to mention one more strange event. Recently, the American Landstat satellite took another picture of the Dead Sea (MM), which shocked scientists. In just one orbital revolution, the color of this reservoir changed to completely black. Oceanologists came to the conclusion that the sea instantly "turned over". The surface layers went down, and those saturated with hydrogen sulfide surfaced.

This can happen when a critical density gradient is reached and is quite possible with our FM. Water saturated with hydrogen sulfide is black in color. Here is an explanation for you - why the World Cup is called black. But before it was called Russian, the Greeks called it hospitable. Only then did it suddenly turn black. Didn't the “reversal” of the layers happen in ancient times?
It is worth noting, and scientists always point to this, that the bottom of the ChM does not have a solid granite slab. That is, the ChM lies directly on the basalts of the mantle and is a remnant of the ancient ocean. The true depth of the ChM in this case reaches 16 km., The depression is filled with sediments.
A simple calculation shows that the volume of sedimentary substances is:
The area of ​​the deep-water part is 211,000 sq. km. * the thickness of the sedimentary layer is 16 km. = 3 million 376 thousand cubic meters. km.
Which exceeds the volume of the entire World Cup by more than 6 times.
At the same time, studies by the expedition of J. Murray in 1910, part of the Meteor expedition, studies on the cable steamer Lord Kelvin, the expedition of W. Snell and many others showed that the layer of sedimentary substances on the bottom of the oceans is 23-35 cm. That is, precipitation accumulate very slowly and slowly.
How could a layer of sediments 16 km thick accumulate in the CM?
At the same time, it should be noted that even at the beginning of the 20th century, hydrogen sulfide was located much deeper. In 1891, Professor A. Lebedintsev raised the first water sample from the depths of the Black Sea. The test showed that the water below 183 meters is saturated with hydrogen sulfide. In our time, poisonous and explosive gas is located at depths of 18 m, and sometimes even breaks to the surface, as happened during the Crimean earthquake of 1927. Then a whole flotilla of fishermen burned down in a flame on the surface of the sea.

There is no need to make idiots out of our ancestors, as if they, drawing the Crimea, did not see that this is a peninsula that protrudes 300 km into the sea. It's just that on the old maps the World Cup is depicted in the form in which it was. And it was a lake in the deep part of the modern World Cup. I already wrote () that presumably, as a result of a huge tsunami, and even more likely - hyper-precipitation, super-powerful rains, all biomass from the Central Russian Upland, the southern part of Ukraine, was washed away into the Black Sea basin. As a result, we have the absence of thick layers of fertile soils in the Non-Chernozem region, wide floodplains of the rivers that do not correspond to their geological history, accumulations of chernozem in places where it was reclaimed, the absence of trees in steppe zone Ukraine, a thick layer of sediments in the steppe part of the Crimea.
At the bottom of the World Cup lie the remains of our ancient civilization. There is vegetation, soil, dead animals and people, flooded cities and riverbeds. Once wooded, full of living creatures, the fertile south of Ukraine has turned into a dry steppe. This happened not so long ago, as scientists would like to inspire us. You can still find references to this fertile region in historical documents. Our ancestors tried to protect themselves from the elements, they built along major rivers colossal hydraulic structures- Zmiyevy Shafts, which are now trying to pass off as defensive structures against small nomads who can only gather in a gang, but not in an army.

The Crimean Isthmus was also dug up, a shaft was made separating the Kerch Peninsula. All for protection from mighty mudflows and floods.
The remnants of our civilization continue to "gas" at the bottom of the World Cup. This is precisely the uniqueness that is inherent in the former Russian, and now the Black Sea.

• All rights reserved Alexandra Lorenz

"Bay" is a word derived from the German Bucht (a separate part of the land). Such pieces of the coast, isolated by the features of the relief, can have large reservoirs. The bays of Crimea (significant only 75) have a variety of attractions. Some of them have been turned into a series of convenient beaches.

Details about bathing recreations can be found at http://hochu-na-yuga.ru/krym/. And here we will only give general information about the Tauride waters, sometimes very stingy. It is worth noting that the peculiarity of the peninsula is that not a single mini-bay is similar to another. For convenience, all bays are divided by geographical location, and the bays of Sevastopol are placed in a separate section. In the review, we move from the East Bank through the South to the West Bank.

Bays of Eastern Crimea

The eastern bays of Crimea lie in two coastal landscapes - steppe (around the city of Kerch and in the Leninsky district), as well as small-rocky (southwest of the city of Feodosia).

Kazantipskaya

A huge inflow in the Sea of ​​​​Azov - between the cape of the same name and the Chagany peninsula. The length of the coast is 28 kilometers (it is already considered a bay, but the second largest after Feodosia). Average depth- 8 meters. On its different sides there are such settlements as Mysovoe and Novootradnoe. The sea edge is shell-sandy. Entry into the water here is quite shallow, "childish". Inside are small coves. About them below.

Arabatskaya

In terms of the length of the water's edge, it takes 2nd place (in the ranking eastern Crimea) - after Kazantipskaya. Popular holiday destination. Indeed, in summer, in local shallow waters, the temperature of the Azov water reaches + 29 ° C. In the west, it rests on an elongated spit with the same name. The surface is mostly shell rock. They get here through the villages of Kamenskoye and Zavodskoye. In the east it borders on the Aktash Upland.

Russian

This is a bay in the west of Cape Kazantip. There is a resort village on its shell rock. It is known only thanks to the elite guest house "Russian Bay" and the proximity to some beaches of the village of Shchelkino. The length of the edge is only 4 kilometers.

Tatar

It is located, on the contrary, in the east of Kazantip (village of Azov), also being part of it. The shell is small. Very clean. The sea is shallow. The place was chosen by windsurfers.

Wide

This is the harbor of the resort village of Semenovka and garden plots adjacent to it.

Turquoise

The southern extension of the Shirokaya Bay (still Semenovka). There is a famous hotel here. Arriving here, you can explore all the iron ore deposits of the Kerch Peninsula. Just take a closer look at the different layers of the 20-meter ravine, the “wall” of the bay.

Kitenskaya

Rest in the bays of Crimea for some tourists is to enjoy the "golden" sands. Some of them go in an arc between Capes Kiten and Krasny Kut (between the villages of Semyonovka and Zavodskoye). The highlight of the location is sandy beaches 30 m wide.

Bulganak (Rifov)

Reef Bay, this place was nicknamed because of the pitfalls. Thanks to them, many ships ran aground (this point is interesting for divers). In the south and southwest, the coasts are steep and steep. Yurkino Farm stands on the southeastern side. In the background is the city of Temir-Oba.

Marine Corps (Chokrakskaya)

Southern end of Perekop Bay

The most northern bay of the western coast (of those that are of recreational importance) is a heavily dissected water area, in the north of which stands the city of Krasnoperekopsk. There are sandy beaches in the extreme south of the bay (the village of Portovoe, Lebyazhy Islands). And the sand here is snow-white, although it is mixed with various plant sediments and shells! In fact, this is the southern section of the Perekop Bay.

Bays of Sevastopol

Those bays of the Crimea, which are located within the metropolis of Sevastopol, are the closest adjacent. No wonder the natives conditionally divide the city into their coastlines. Locality was created as the largest Crimean port - just when taking into account amazing features local (exceptionally rocky) coast.

Sevastopol

We are talking about the largest bay of the Black Sea, because its area is 8 square kilometers, and the length of the coastline is almost 25.5 kilometers. It is of strategic importance for the Russian Federation - the main base of our fleet is located here. It is also located far from the last important trading port. There are marine factories and enterprises. Inside this water area (like in a large matryoshka doll) there are several more bays hidden. The eastern end of this basin is the estuary of the Chernaya River. And in terms of ease of navigation, only the bays of Hong Kong and Sydney can be compared with this corner of the oceans.

South

The rest of the bays of Sevastopol, lying inside the bay of Sevastopol, do not have such monumental significance. This is the most prestigious place in the city (Sea and Railway Stations, Grafskaya Pier, Lenin St. and many other business cards are located here).

Quarantine

These bays of Sevastopol (Southern and Karantinnaya) are separated by a small Artillery Bay. Unlike the first, the second is two-section.

Sandy (New)

Further to the west, the southern side of the Sevastopol Bay continues with this water area. The boulevard of the park named after A. Akhmatova and st. Efremov. There is a beach here. It consists of imported sand. This explains the name of the "new" harbor.

Streletskaya

The “deepened” bays of Crimea continue to move west, the longest is Streletskaya. Around it is Rybatsky Pier Avenue and the Presidential Cadet School.

Holland

This is the only bay of Sevastopol known to tourists, lying on the northern side of the Sevastopol Bay. On its embankments there is the Poklonny Cross, the square of Kurchatov Street, a noisy beach.

Cossack

Some bays of Crimea are outgrowths of larger bases. For example, Cossack Harbor is the eastern part of the Double Bay. It is popular for the excavations of Strabonov Chersonese, an abandoned airfield, three beaches, and also for riding on “water parachutes”.

Marble (Moon)

It is located far south of the center of the agglomeration - 2.5 kilometers east of Cape Fiolent. Pink limestone is mined here, very similar to marble. Reminds me of a sickle.

The city district also includes four more well-known bays of Sevastopol:

• Kamyshovaya - coordinates 44.584000, 33.424937. Oil berths, Rybakov street.
• Salty - coordinates 44.575320, 33.404096. 4 beaches, dolphinarium, airfield museum.
• Artillery - coordinates 44.613761, 33.518766. Embankments of Kornilov and Klokachev, Southern Hermitage, dolphinarium and zoo, 7 prestigious restaurants.
• Round - coordinates 44.601562, 33.444970. Yacht club, Parus stadium, Omega beach, Green Theatre, ruins of ancient settlements, a sanatorium, a hotel, 3 restaurants and an arboretum (located on Heroes of Stalingrad Avenue).

So, we have chosen for you the most curious (from the point of view of travelers) bays of Crimea. To those who are honored big story, photos are attached. And the role of bays can theoretically be performed by some lakes, resting with their ends already in the sea, but this is a completely different story ...

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 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 life of the Black Sea. And at this stage, we, people, are strenuously helping nature to "accelerate" the course of the Black Sea history...

The Black Sea is familiar to the inhabitants only superficially. Everyone knows the types of fish that are caught here, many are familiar with the features of the sea coast in certain areas. But what is hidden under the water column is known only to researchers and scientists. The Black Sea is a deep-water basin with steep slopes.

It is a mistake to believe that in the Black Sea the bottom abruptly goes down immediately from the coast. A depth of 100 meters begins mainly at a distance of 200 kilometers from the coast in the north-west of the sea, in the main part - at a distance of 10-15 kilometers, in the Crimean region and the city of Gagra - about 1 kilometer from the coast. The bottom of the Black Sea is flat, but there are hills with gentle slopes, cracks and ledges.


The deepest place that was registered in the Black Sea is 2211 meters. In 1971, after a reception in Moscow, the researchers managed to visit the Yalta depression. This is one of the most deep depressions Black Sea. The crew of four people on the Sever-2 apparatus descended to a depth of more than 2 kilometers. The head of the group was M.N. Diomidov, a Soviet designer of deep-sea submersibles. As a result, aquanauts saw that life in the Black Sea exists in a narrow surface layer 100 meters from the surface. Below this mark, the researchers saw in the light of searchlights only organic remains, which made the surrounding landscape look like a winter day, descending to the seabed in the form of large flakes of snow.

The scientists managed to descend to the bottom of the Black Sea, walk a little along it and return to the base in one working day. Since the Black Sea is quite young, it is possible to draw certain conclusions by studying its geology.

For example, some hoped to decide which came first: the continental theory or the oceanic one. There are two types of structure of the earth's crust - continental and oceanic. Under the continents, no sedimentary layer was found, the basalt layer turned out to be thicker than under the oceans, and there is also another layer - granite, located above the basalt. Under the oceans, a sedimentary layer with a thickness of 2 to 5 kilometers is formed, below - basalt, under which magma flows.

The Black Sea partly confirms the continental theory: the earth's crust is hidden under its waters, which is similar in structure to the ocean, however, the layer of sedimentary rocks reaches 10 kilometers, the basalt plate is much thicker than under the oceans, but at the same time less than under the continents. The granite layer was found only in the coastal zone. Some scientists are sure that the oceans were the first to form, then the primary type of the earth's crust would be basalt, which is why basalt rocks lie shallow under the oceans. Magma came out through cracks, which became the basis for the formation of continents. The oceanic structure of the bottom of the Black Sea confirms that at first the entire planet was covered with continents.