Physical map of the Black Sea
The area of the Black Sea - 422 000 km ² (according to other sources - 436 400 km ² ). The outlines of the Black Sea resemble the oval with the greatest axis of about 1150 km. The greatest extent of the sea from north to south - 580 km. Maximum depth - 2210 m , the average - 1240 The volume of water in the sea is 555 km3. A characteristic feature of the Black Sea is complete (except for a number of anaerobic bacteria), the absence of life at depths of 150-200 m due to the saturation of the deep layers of water with hydrogen sulfide.
The sea washes the shores of Russia, Ukraine, Romania, Bulgaria, Turkey, the partially recognized Abkhazia and Georgia (areas located around the sea, traditionally referred to as the term "Black Sea").
Black Sea - an important area of transportation, as well as one of the largest resort areas in Eurasia. In addition, the Black Sea remains an important strategic and military importance. In Sevastopol and Novorossiysk are the main military base of the Russian Black Sea Fleet in Sevastopol and Novoozerne - Naval Forces of Ukraine, in Sinop and Samsun based grouping of the Black Sea Navy of Turkey, in Varna - Bulgaria's Navy, Poti and Batumi - Georgian Navy (currently time - the Department of State of the Coast Guard of the Border Police of Georgia , in Constanta and Mangalia - Navy Romania.
Name
The Greek name of the sea - Pontus Aksinsky (Greek Πόντος Ἄξενος, «Inhospitable Sea"), found the name "Scythian". In "Geography" of Strabo (7.3.6) it is assumed that the title Sea received because of difficulties with navigation, as well as wild hostile tribes inhabiting its shores. But most likely the Greeks embraced the local Scythian name of the sea, representing reflex etc. Iran. * Axšaina - «dark blue", "dark", correlated to its current title and reinvent it in consonance with the Greek word "inhospitable". Later, after the successful development of the coast of the Greek colonists, the sea was called Pontus Euxine (Greek Πόντος Εὔξενος, «Hospitable Sea"). However, in Strabo (1.2.10) there is mention of the fact that in the ancient Black Sea and just called "the sea» (pontos). In more recent times, VI-XVII centuries, both in Russian and in Arabic, Italian, and other sources through active sea navigation Slavs used the name "Russian Sea". In "The Tale of Bygone Years" states "A Dnepr vtechet in Pontskoe sea trmi Zherelo, hedgehog sea slovet Ruska ..." .
The modern name "Black Sea" found its corresponding map in most languages kabard.-cherk. XLI shIutsIe, Greek. Μαύρη θάλασσα, Bulg. Black sea cargo. შავი ზღვა, rom. Marea Neagră, Eng. Black Sea, tour. Karadeniz, Ukr. Nintendo sea Abkh. Amshyn Eiқәa et al There are a number of hypotheses about the causes of the name:
Turks and other invaders who tried to conquer the people of the seashore, met fierce resistance from the Circassians (Cherkess), Abkhaz and other tribes, for which he was nicknamed Sea Karadeniz - black, inhospitable.
Yet another, the origin of the name is based on the fact that metal objects (eg, anchors), dropped in water deeper than 150 m of the sea for a long time, covered with a touch of black by the action of hydrogen sulfide.
Another hypothesis related to the adoption of several Asian countries, "color" the designation of the world, where "black" meant the north, respectively, the Black Sea - North Sea.
Geography
The Black Sea coast are cut small, and mostly in its northern part. The only large peninsula - Crimea. The largest bays Yagorlytsky, Tendrov, Dzharylgach, Karkinitsky, Kalamitsky and Feodosia in Ukraine, Varna and Burgas in Bulgaria, Sinop and Samsun - the southern coast of the Sea, in Turkey. In the north and north-west of the confluence of the rivers spill estuaries and brackish wetlands are areas . The total length of coastline - 3,400 km.
Several parts of the coast of the sea have their own names: Southern Coast of Crimea in Ukraine, the Black Sea coast of the Caucasus in Russia, Rumelian Beach and Anatolian coast in Turkey. In the west and north-west coast of the low-lying, sometimes steep, and in Crimea - mostly low-lying, with the exception of the southern coast and mountainous peninsula Tarhankut west. On the eastern and southern shores of the sea close to the foothills of the Caucasus, and come close Pontic Mountains.
Islands in the Black Sea is not enough. Dzharylgach largest island, with an area 62 km ². The rest of the island is much smaller, the largest - Berezan and the Snake (both of less than 1 km ²).
Flow into the Black Sea following major rivers: the Danube, Dnieper, Dniester, as well as smaller Mzymta Psou Bzyb Rioni, Kodori, Inguri (East Sea), Chorokhi Kızılırmak, Eshilyrmak, Sakarya (in the south), the Southern Bug ( the north). Annual river discharge into the Black Sea is about 310 km3, with 80% of this water shall be made in the north-western part of the shelf, mainly the Danube and Dnieper
Geology
Black Sea fills an isolated basin, located between the South-Eastern Europe and Asia Minor. This depression formed in the Miocene epoch, in the process of active mountain building, divided the ancient Tethys Ocean into several water bodies (of whom later than the Black Sea, Azov formed, the Aral and Caspian Seas).
One of the hypotheses of the Black Sea (see Black Sea deluge theory) states that 7,500 years ago it represented the deepest freshwater lake in the world, the level was lower than now more than a hundred meters. At the end of the ice age sea levels rose and the Bosphorus isthmus was broken. Flooded a total of 100 thousand km ² (most fertile land already cultivated people). Flooding of these vast lands, may have become the prototype of the myth of the Flood. Interestingly, the same version of the origin of the sea were even Pliny the Elder . The emergence of the Black Sea according to this hypothesis presumably accompanied by mass mortality of freshwater lakes of the living world, the product expansions - hydrogen sulfide - reaches high concentrations at the bottom of the sea.
Black Sea Basin consists of two parts - east and west, separated by a show of being a natural extension of the Crimean peninsula. The northwestern part of the sea is characterized by a relatively wide band of shelf (up to 190 km). South Coast (owned by Turkey) and east (Georgia) is a cool character, the bar shelf is 20 km and is dissected by a number of canyons and valleys. The continental slope of the Black Sea significantly dismembered submarine valleys. In the south of the sea, between Sinop and Samsun parallel to the coast is a system of submarine ridges. The central part of the Black Sea basin is a relatively flat plain. Depth off the coast of the Crimea and the Black Sea coast are increasing very rapidly, reaching elevations above 500 m is a few kilometers from the coastline. Maximum depth (2210 m) reaches the sea in the center, south of Yalta.
In the composition of rocks, stacking bottom of the sea in the coastal zone is dominated by coarse deposits: pebbles, gravel, sand. Away from the coast are replaced fine sands and silts. In the north-western Black Sea common coquina, for the bed slope and sea basin common pelitic silt.
Among the major mineral deposits which are at the bottom of the sea: oil and natural gas on the North West Shelf, offshore placer sands titanomagnetite (Taman Peninsula, the coast of the Caucasus) . Stocks of methane stored in the form of gas hydrates in deep-sea sediments of the Black Sea, was first found by the Internal VNIIGAZ AG Ephraim and Zhizhchenko in 1972 (cruise of the "Moscow University" ), current estimates are as high as 25 - 49 trillion cubic meters of gas.
Hydrology and hydrochemistry
The water balance of the Black Sea consists of the following components :
precipitation (230 km ³ per year);
continental runoff (310 km ³ per year);
the flow of water from the Sea of Azov (30 km ³ per year);
water evaporation from the sea surface (-360 km ³ per year);
removal of water through the Bosphorus (-210 km ³ per year).
The quantity of precipitation, with income from the Azov Sea and the river flow exceeds the amount of evaporation from the surface, so that the level of the Black Sea more than in Marmara. With this formed upstream directed from the Black Sea through the Bosporus Strait. Downstream, observed in the lower layers of water, less strongly expressed and sent through the Bosphorus in the opposite direction (see the underwater river in the Black Sea). Interaction of these trends further supports vertical stratification of the sea, and is also used for fish migrations between the seas.
It should be noted that due to the complicated exchange of water with the Atlantic Ocean and the relatively small size of the Sea to the Black Sea tidal range is very small and is only observed on the devices. At the same time, sufficiently well defined wind-surge phenomena under the influence of strong winter winds that reach 2 m in the north-western part of the basin. When winter storms can form waves up to 8.6 m in coils periodically occur seiches - standing water level fluctuations, with amplitude of up to 40-50 cm, and the oscillation period of a few minutes to several hours.
The Black Sea is the world's largest meromictic (with necmeshivaemymi layers of water) pond. Two masses of Black Sea water: surface - desalinated and oxygen-rich and close to the air temperature and depth - more salty and dense, with a constant temperature, oxygen-free (anaerobic zone), separated by a boundary layer of water at a depth of 30 to 100 m (so called cold intermediate layer or CIL). His temperature is always lower than that of the deep water, as by cooling in the winter, he does not have time to warm up for the summer. A layer of water in which the temperature changes drastically, called the thermocline, a layer of rapid changes in salinity - the halocline, the density of water (depending on the temperature and salinity) - pycnocline. All those sharp vertical changes in the properties of water in the Black Sea region are concentrated in the CIL. Such vertical stratification (layering) of Black Sea water salinity, temperature and density prevents the vertical mixing of the sea and the depths of oxygen enrichment of hydrogen sulfide . At depths of 150-200 meters in the Black Sea chemocline is present, then there is a layer of sharp changes of hydrochemical parameters (first of all, is the transition between oxygen and hydrogen sulphide zones).
Single generally accepted explanation for the origin of hydrogen sulfide in the Black Sea yet. It is believed that this compound is in the Black Sea is formed mainly as a result of vital activity of sulfate-reducing bacteria, pronounced stratification of the water and the weak vertical exchange. Hydrogen sulfide concentration increases with depth of 150 m, accounting for 0.19 mg per 1 liter of sea water to a depth of 2000 m, where it reaches the maximum concentration of 9.6 mg / l of water. Thus, if we assume an average concentration of 5.73 mg / l at a depth of 1240 m, the approximate amount of hydrogen sulfide in the Black Sea is 3.1 billion tons Some recent studies suggest the Black Sea as a giant reservoir not only hydrogen sulfide and methane emitted probably also in the process of microbial activity, as well as from the bottom of the sea.
The circulation of water in the sea covers mainly the surface layer of water. This layer of water has a salinity of about 18 ppm (in the Mediterranean - 37 ppm) and saturated with oxygen and other elements necessary for the activity of living organisms. This layer in the Black Sea is subject to cyclonic circulation circular direction around the perimeter of the pond. Simultaneously, in the coastal parts of the sea constantly fixed local water circulation anticyclonic direction. The temperature of the surface layers of water, depending on the season, in the open sea ranges from an average of 6 to 25 ° C , sometimes reaching 30 ° C in the shallow water off the coast in the summer and freezing in winter along the coast.
The bottom layer due to saturation with hydrogen sulfide, contains no living organisms, with the exception of a number of anaerobic sulfur bacteria (waste product of which is hydrogen sulfide). Salinity is increased to 22-22,5 ppm, the average temperature is ~ 8,5 ° C, the temperature at the maximum depth is 9,0-9,1 ° C.
The circuit currents of the Black Sea are two huge closed cycle with a wavelength of 350-400 km. In honor of Nicholas Knipovich oceanographer who first described this scheme, it was called "Points Knipovich" .
Climate
The climate of the Black Sea, in connection with his position srednekontinentalnym mainly continental. The Black Sea coast and the southern coast of the Crimea are protected by mountains from cold northern winds and therefore have a mild Mediterranean climate, and to the south-east of Tuapse - a humid subtropical climate.
Beach in Sunny Beach (Bulgaria)
Significant impact on the weather in the Black Sea has the Atlantic Ocean, on which arises most cyclones bringing bad weather at sea and storms. In the north-east coast of the sea, especially in the area of Novorossiysk, the low mountains are not a barrier to the cold northern air masses that, rolling over them, results in a strong cold wind (boron), the locals call it the "Nord-Ost". South-westerly winds in the Black Sea region usually brings warmth and quite humid Mediterranean air masses. In summer, the sea is a spur of the Azores anticyclone. As a result, for most of the sea with warm wet winters and hot, dry summers.
The average January temperature in the northern part of the Black Sea +2 ° C, but in some years can drop up to -10 ° C or more. In the areas adjacent to the South coast of the Crimea and the Caucasus, the winter is much milder: the temperature rarely drops below +5 ° C. Snow, however, occasionally falls in the northern seas. The average July temperature is in the north sea - +23 - +25 ° C. Maximum temperatures are not so high due to the mitigating effect of the water tank and do not usually exceed 37 ° C. The warmest place on the Black Sea coast - the coast of the Caucasus, in particular the city of Gagra on the territory of modern Abkhazia (average annual temperature +17 ° C).
Most rain falls in the Black Sea on the coast of the Caucasus (1500 mm per year), the lowest - in the north-western part of the sea (about 300 mm per year). Clouds over the year an average of 60%, with a maximum in winter and minimum in summer.
The waters of the Black Sea, as a rule, are not subject to freezing. However, in very severe and prolonged winter, the northern part of the sea may be covered with ice, but it is no more than once every few decades. Average water temperature in the sea is not lower than +7-8 ° C .
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