The Black Sea appeared more than 5.3 million years ago as a result of the division of the Tethys Ocean.

Now the sea belongs to the pool Atlantic Ocean. Distinctive feature is that it is limited by banks on all sides.

In the sea, already at a depth of 150-200 meters, it is almost impossible to detect signs of life due to the high concentration of hydrogen sulfide.

On the political map you can see that it washes the shores of 7 countries: Abkhazia, Bulgaria, Georgia, Russia, Romania, Turkey and Ukraine.

The sea has great diversity organic world And natural resources. What else is the Black Sea rich in? How does a person influence his ecology?

Black Sea resources

The biological resources of the Black Sea are fish, plants, gas and oil.

What do they mine?

The fauna does not have as many species as in other seas. Not found here sea ​​stars, corals, octopuses, cuttlefish. Fish are mainly represented by the following species:

There are also those that, due to human fault, were included in the Red Book: thorn, Russian sturgeon, .

Invertebrates - mussels and oysters, crayfish and shrimp - have become the object of fishing. In total, about 300,000 tons of seafood are produced per year.

Plants are mainly represented by unicellular and multicellular algae:

Minerals:

• There are oil deposits explored on the shelf and natural gas. They are now being actively developed on the shelf by the Chernomorneftegaz enterprise.
• Deposits of ferromanganese ores, and in the sea area - reserves of gravel and construction sands.
• The shallow waters are rich in shell rock, used for glass production and construction.

Damage

Due to active human activity, the animal rapidly contracts and flora. Some species are now even on the verge of extinction! To prevent complete disappearance, nature reserves were created: Karadag, Danube, and Black Sea.

Ecological state

Black Sea water last years began to become increasingly polluted by petroleum products, wastewater and industrial waste. Unfortunately, the environmental condition only worsens every year, although people are making every effort to correct the situation.

Conclusion

The Black Sea is one of the most amazing places on planet Earth. It is at the same time an important deposit of natural resources, a transport area, a tourist destination and a strategically important site. However, due to man's ignorance and careless attitude towards environment The sea is going through hard times.

The Black Sea is home to 184 species and subspecies of fish, of which 144 are exclusively marine, 24 are anadromous or partially anadromous, 16 are freshwater. In recent years, the ichthyocenosis of the Black Sea has been replenished by the Far Eastern mullet Mugil so-iuy Basilewsky, which has successfully acclimatized in the Azov-Black Sea basin.

Marine fish species of the Black Sea are usually divided into 4 groups: permanently inhabiting (Black Sea anchovy race, Black Sea horse mackerel, Black Sea sprat, Kalkan); wintering in the Black Sea, but spawning and fattening in the Sea of ​​Azov (Azov race of anchovy, Kerch race of herring); wintering and spawning in the Black Sea, but feeding in the Azov Sea (mullet, Black Sea mullet); developing the Black Sea as a spawning and feeding area, but wintering or spawning in Mramornye and Aegean seas(bonito, mackerel).

V. Vodyanitsky (1941) gave the following diagram of the food relationships of Black Sea fish. (according to L.A. Zenkevich. 1963) (Fig. 1.)

The number of most Black Sea fish depends not only on the conditions of their existence in the Black Sea, but also on the conditions of spawning, feeding or wintering in adjacent seas, which determines the complex type of dynamics raw material base the whole sea.

From total number About 20% of fish serve as commercial targets. In the 70s and 80s, the USSR added about 200 thousand tons of fish and seafood to the Black Sea. The basis of the catch was the Black Sea race of anchovy, sprat, whiting, horse mackerel, and katran (Table 1). Catching other fish - mullet, mullet, herring, perch, etc. off the coast former USSR very limited due to their low numbers.

Fishery research has established that significant interannual fluctuations in the number of fish in the Black Sea are accompanied by changes species composition catches So from the late 40s to the mid 50s. In the Black Sea, planktivorous fish dominated - anchovy and Black Sea horse mackerel. Subsequently, until the 60s, the catch was dominated by

Table 1 USSR catches of the main commercial fish of the Black Sea (1975 - 1990), thousand. T.

Since 1974, more than 95% of the catch has been anchovy, Black Sea sprat, whiting and horse mackerel. According to FAO, the total catch of the listed fish in 1971-1984. tended to increase, which is associated with the expansion of the scale of their fishing.

Various researchers have estimated the initial stocks and production of fish in the Black Sea at 0.5-5.7 million tons and 0.25-2.9 million tons, respectively. Such a large range is associated with both the methodological approach and large interannual fluctuations number of commercial fish in the reservoir. In addition, at present, anthropogenic factors are a significant “regulator” of the number of commercial fish, which influence not only the abiotic, but also the biotic part of the Black Sea ecosystem.

The results of Ukrainian research over the past ten years allow us to speak about the initial stock of pelagic fish (anchovy, horse mackerel, sprat) at the level of 2-3 million tons, demersal fish (merlang, katran, galkan, etc.) - 0.3-0.7 million .T. This assessment did not include information on Mediterranean migrants (lufal, mackerel, bonito), since their migrations to the former USSR zone have practically not been observed in the last 20 years.

The commercial importance of the Black Sea is determined not only by fish resources, but also by significant reserves of invertebrates (mussels) and algae (phyllophora), the size of populations and associations of which are influenced by various types economic activity are undergoing significant changes.

In addition to fish, invertebrates and algae, the Black Sea is home to mammals. So, here there are three species of dolphins (white-sided, bottlenose and Azov), which have long been hunted by all Black Sea countries. The number of dolphins was previously large, and the total production exceeded 10 thousand tons per year, which led to sharp decline their reserves. Since 1966, dolphin fishing has been prohibited.

The general fishing regime in the Black Sea is determined by the principles of rational use of fish resources in accordance with the state of the stocks of the exploited objects. However, due to the lack of concerted action in industrial operation and biological resources problems of international fisheries regulation arise.(2)

Glow of the sea. In the Black Sea, a sparkling glow is observed, caused by flashes of small and microscopic marine organisms (nocturnal moths, peridinians) and representing separate sparks of the same color. Its intensity increases with waves, the passage of a ship, etc. A sparkling glow is usually observed in summer and autumn. It is especially intense in the coastal zone.

Sea blooms are caused by the massive accumulation of planktonic (usually plant, but sometimes animal) organisms in the surface layer of water. During flowering, the transparency of the water decreases significantly and its color changes; the water takes on a yellow, brown or reddish tint. In the described area, water blooms are observed mainly in the northwestern part of the sea, as well as in bays and bays. It is possible throughout the year, but is most likely from February to May.

Seaweed. In the Black Sea, the red algae Phyllophora is especially common, forming huge thickets in the northwestern part of the sea at depths of 20-60 m. Other algae include diatoms, pyrophytes, blue-green and brown ones. In bays, estuaries, lagoons and bays at depths usually no more than 10-12 m, zoster, or sea grass, is often found.

Woodworms. In the Black Sea, the destructive activity of marine wood borers is noted. Among the bivalve mollusks, Teredo is found here, and among the wood-boring crustaceans - Limnoria and Chelyura.

Teredo usually destroys wood from the inside; its passages are directed along the fibers, but can also bend in the most bizarre way, intertwining with each other. With significant damage, the wood turns into a spongy mass. Teredo activity is especially active from June to September. It is most often found off the coast of the Crimean Peninsula and off the eastern coast of the sea.

Limnoria usually attacks wood from the surface. Its passages are shallow (no deeper than 5 mm, occasionally 15 mm from the surface), but sometimes it eats out like hollows in the piles, the so-called “cauldrons”. Limnoria, as a rule, does not tolerate muddy, stagnant, oxygen-poor water.

Chelyura is somewhat larger than Limnoria; she usually settles next to it and drills into the tree in a similar manner. Its passages are deeper, although it does not create “cauldrons”. The diameter of the strokes is about 2.5 mm.

In addition to wood, limnoria and chelyura can affect the insulation of submarine cables.

Fouling of marine organisms on the underwater parts of ships has been observed all year round, but it is most intense from May to September. Balanuses, mussels, dracenas, bryozoans, etc. are common here.

Dangerous sea animals. The spines of the dorsal fin and the spines of the gill covers are very poisonous, their injections can be fatal. The large dragon lives mainly in bays and bays; it usually buries itself in soft ground so that only its head is visible.

European scorpionfish are most often found in the Black Sea by predatory and poisonous marine animals; They should be avoided when swimming, working without a diving suit and disembarking personnel. It is home to the spiny dogfish shark, great dragonet, European scorpionfish and European stingray.

The big dragon is the most dangerous fish It is found in bays near rocky shores; it usually hides in rock crevices or in algae. The injections of this fish are very painful.

The European stingray, or sea cat, lives in sheltered bays, shallow sea areas and river mouths. With blows of its tail it can inflict very strong and dangerous wounds.

In addition, a small green, red or brown sea anemone jellyfish is found in the Black Sea. Contact with it causes severe skin irritation.

Mineral wealth of the Black Sea

The Black Sea is currently the most promising for oil and gas resources. And the first ferromanganese nodules in the Black Sea were discovered back in 1890 by N.I. Andrusov. A little later, such scientists as Zernov S.A., Milashevich K.O., Titov A.G., and Strakhov N.M. were engaged in their detailed study. on this moment three have been explored and discovered in the Black Sea different belts nodules: west of the Rioni River delta, south of Cape Tartankhut, as well as on the continental slope east of Sinop and on the Turkish part of the shelf.

In addition to all this, the coast and bottom of the Black Sea in Lately are considered as the main places where tin, diamonds, platinum, ore metals and titanium can be mined. The Black Sea is also a storehouse of building materials such as shell rock, pebbles and sand.

Mineral wealth of the Azov Sea

The shallowest sea is rich in minerals, hidden not only under water, at the bottom, but often even in the depths of the seabed. The most important among its hidden treasures are the potential oil and gas resources of the water area. Gas fields (Kerch-Taman region - in the south, in the vicinity of the village of Strelkovoe - in the west, Beisugskoye - in the east, Sinyavinskoye - in the northeast) seem to frame the entire Sea of ​​​​Azov. Throughout the local water area and around, the main promising oil and gas bearing horizon is the Lower Cretaceous sediments, to a lesser extent - Paleocene, Eocene, Maikop, Miocene and even Pliocene rocks. From the point of view of oil content, the Maikop ones are the most interesting.

The total thickness of the sedimentary cover in the southern part of the sea - in the Indolo-Kuban depression - is enormous and reaches 14 km. A significant part of this powerful section is promising for oil and gas.

Along the shores of its western half is the Azov-Black Sea Neogene iron ore province, represented by oolitic iron ores Cimmerian age. In the northwestern part of the sea, within the so-called Molochansky graben, the presence of large deposits is likely iron ores with reserves of several billion tons. They are presumably localized along the northern slope of the Azov swell and within the entire negative structure of this graben.

Another type of mineral raw material supplied by the Sea of ​​Azov is table salt. sea ​​salt extracted from Sivash. And a lot: about 60 thousand tons.

Major minerals from the bottom of the seas

The first place among them is occupied by oil along with flammable gases, followed by iron and manganese ores, bauxite, limestone, dolomite and phosphorite.

Oil is a mixture of various hydrocarbons, i.e. compounds of carbon with hydrogen. It is fluid, capable of moving underground over considerable distances. During these movements, oil droplets scattered in rocks can accumulate into large oil deposits.

According to the teachings of academician I.M. Gubkin (1871-1939) oil was formed in sedimentary rocks of all geological eras. “It arose precisely in those cases where there were favorable conditions for sedimentation of a lagoonal, coastal or lacustrine nature, which contributed to the accumulation of organic material from which oil was subsequently formed.”

Oil and gas fields are found in foothill troughs, in subsidence zones mountain ranges and in extensive tectonic depressions within platforms. Such places are favorable for the accumulation of thick layers of sandy-clayey or carbonate sediments. Along with these sediments, interspersed with them, semi-decomposed remains also accumulate various organisms, mostly small, microscopic. Some of this organic material gradually turns into oil over geological time. Water displaces oil from clays and other source rocks where it originated into coarsely porous rocks, or “reservoirs,” such as sands, sandstones, limestones and dolomites. If there is a layer above the reservoir that is impermeable to oil in the form of dense clay or other rock, then oil accumulates under such a seal, forming a deposit. The richest oil deposits are found in the crests of uplifted layers. Wherein top part The arch under the impermeable layer is occupied by flammable gas, below is oil, and even lower is water (Fig. 1).

Rice. 1

That is why petroleum geologists first of all study the bends or structures of layers, look for underground vaults or other similar “traps” of oil placed by nature along the paths of its underground movement.

In some places, oil comes to the surface of the earth as a spring. At such sources it forms thin multi-colored films on the water. The same type of film is also found in ferruginous sources. Upon impact, the ferrous film breaks into sharp-angled fragments, and the oil film into round or elongated spots, which can then merge again.

The relatively rapid accumulation of sedimentary rocks is one of the necessary conditions for the formation of the oil source strata. Ores of iron, manganese, aluminum and phosphorus, on the contrary, accumulate very slowly, and even if the ore minerals of these metals are formed in the source strata, they turn out to be dispersed in them, not representing any interest for extraction.

Deposits of marine ores of iron, manganese, aluminum and phosphorus have the form of layers, sometimes short, sometimes stretching over long distances. The layers of some phosphorites stretch for tens and even hundreds of kilometers. For example, a layer of phosphorite from the “Kursk nugget” runs from Minsk through Kursk to Stalingrad.

All these ores were deposited in shallow places of the seas and lie among marine shallow sandy-clayey or calcareous rocks. The formation of iron, manganese and aluminum ores is characterized by a close connection with the adjacent land - with its composition, topography and climate. In conditions humid climate and with a flat or hilly land topography, the flow of rivers is calm and therefore they carry little sand and clay and relatively many dissolved compounds of iron, and sometimes aluminum and manganese. During its decomposition, the dense vegetation of humid climate regions produces many acids that destroy rocks and allow the released compounds of iron, manganese and aluminum to move in dissolved form. In addition, dense vegetation protects the land from erosion, which also reduces the amount of sandy-clayey turbidity in rivers.

The composition of the rocks that make up the land, as well as the climate, determine relative amount ore elements carried from land. Basic rocks, especially basalts and diabases, provide a lot of iron and manganese. In humid tropics, aluminum is more easily washed out from basalts and nepheline rocks, and more difficult from granites.

Rivers carry dissolved compounds of iron, manganese and aluminum into the sea, where they are deposited. If few contaminants are deposited at the same time, relatively pure ore deposits can form. Favorable places for the accumulation of these ores are calm bays or lagoons.

Slow accumulation of sediments can occur not only on platforms, but sometimes also in geosynclines. Since the main rocks (diabases, basalts and others) often came to the surface over large areas in geosynclinal areas, there were no less, but more opportunities for the accumulation of ores in them than on platforms. For the accumulation of sediments, it is also important that geosynclinal areas are not characterized throughout their entire area by instability of the earth’s crust or rapid accumulation of sediments. They contain areas that are at times relatively stable, which contributes to the slow accumulation of sedimentary rocks. Such areas are precisely of the greatest interest from the point of view of sedimentary ore formation.

At the beginning of industrialization, our Motherland experienced an urgent need for aluminum ores- bauxite. At that time, the prevailing theory here and abroad was that bauxite was formed on land as a result of tropical weathering. Academician A.D. Arkhangelsky, based on a detailed study of bauxites, came to a completely different conclusion. He found that the largest and highest quality bauxite deposits are not of land, but of marine origin and formed in geosynclines. Geological parties were sent to areas of geosynclinal marine sediments favorable for the formation of bauxite. These geological searches culminated in the discovery of a number of new rich bauxite deposits in Devonian marine sediments in the Urals, which provided our aluminum plants with domestic raw materials. The Devonian bauxites of the Urals were deposited, although in a geosynclinal region, but at such moments of its life when the accumulation of sediments occurred slowly, with interruptions and temporary retreats of the sea. A significant portion of these bauxites were deposited on land in depressions among limestones.

The origin of phosphorite deposits is interesting. Due to the conditions of their formation, they do not have such a close connection with the land as metal ores. Phosphates dissolved in sea water are characterized by the fact that they are very important and, moreover, scarce nutrient for marine organisms. Phosphates feed plants, which in turn are eaten by animals. Dead organisms, sinking to the bottom, take phosphorus with them. During their decomposition, they release it on the way to the bottom and partly at the bottom. As a result, the upper layers of water are depleted in phosphorus, and the lower layers are enriched with it. Starting from a depth of 150-200 m, its concentration is 5 or 10 times higher than at the surface of the water, and the highest concentrations of dissolved phosphates are formed in silt or groundwater. In these waters at the bottom of the sea, phosphates precipitate from solution. Phosphorites have the form of continuous layers, cavernous slabs or nodules of various types.

The origin of almost all phosphorite layers is associated with interruptions in the accumulation of sedimentary strata, which was especially noted by A.D. Arkhangelsk. This fact is apparently explained by the fact that phosphorites were deposited in relatively shallow water conditions, at depths of approximately 50-200 m, so that a slight rise in the seabed was enough for them to end up in the zone of wave erosion.

White chalk and limestone are also of marine origin. Both of them consist mainly of calcite or calcium carbonate and differ neither in mineralogical nor in chemical composition, and in terms of its physical state - white chalk is soft, it is composed of tiny uncemented particles; limestone, on the contrary, is strong, the particles composing it are larger than in chalk.

Layers of white chalk come to the surface in many places in Ukraine, on the Don and on the Volga. More than half of the chalk consists of the remains of microscopic calcareous algae coccolithophores (Fig. 2). Modern coccolithophores swim near the surface of the water, moving with the help of their flagella. They inhabit mainly warm seas.

In addition to the remains of coccolithophores, microscopic calcite shells of rhizomes, or foraminifera, as well as mollusk shells and remains are often found in the Cretaceous sea ​​urchins, crinoids and flint sponges.

The amount of remains of coccolithophores in chalk is usually 40-60 percent, rhizomes - 3-7 percent, other calcareous organisms - 2-6 percent, and the rest is powdery calcite, the origin of which has not yet been clarified.

The predominance of remains of calcareous algae in the composition of chalk was established back in the last century by Kyiv professor P. Tutkovsky and Kharkov professor A. Gurov

Limestones also largely consist of calcite organic remains - shells of mollusks and brachiopods, remains of echinoderms, calcareous algae and corals. Many limestones have changed so much that appearance it is difficult to determine what origin they are. There are still disputes about such limestones: some say that calcite in them was chemically precipitated from solution sea ​​water, others argue that limestone is composed of organic remains, which have now been changed beyond recognition.

In his recently published work, Professor N.M. Strakhov proved that almost all marine limestones were formed due to the remains of calcareous organisms, and the chemical precipitation of calcium carbonate in the sea occurs in very limited quantities. Indeed, white limestones Cretaceous period, widespread in the Crimea and the Caucasus, at first glance are extremely poor in organic remains, but upon careful study they contain a large number of remains of coccolithophores and rhizomes. This means that these limestones were previously chalk, and then became very compacted.

The use of limestone is very diverse. They go to crushed stone for highways and railways, into rubble for laying foundations, and some of the densest of them are used for cladding buildings like marble. In such marbles one can see shells of brachiopods and mollusks, sea ​​lilies, calcareous algae and corals. Limestones are also widely used for the production of lime and cement, for liming soils, in metallurgy, in the production of soda, glass, and cleaning sugar syrup and production of calcium carbide. Chalk, where high strength is not required from it, is used in the same way as limestone.