The Black Sea, a strange geography

The Black Sea is the largest inland sea that still maintains regular communication with the world's oceans.

This communication takes place through the narrow Bosphorus Strait that leads to the Mediterranean Sea, which in turn connects it to the Atlantic Ocean.

It has a more or less oval shape. Its longitudinal axis is approximately 1,150 km long, and its latitudinal axis is 611 km. It has an area of ​​423,000 km2. The average depth is 1,300 m, and the greatest depth is 2,245 m. The volume is 547,000 km3.

Geological history.

The Black Sea is considered a residual basin of the Tethys Sea of ​​Central Europe, which existed from the end of the Paleozoic era to the Middle Tertiary period. As a result of alpine orogenic movements in the Triassic period, the Tethys Sea was divided into a series of basins. One of them was Pontus, which stretched from Moldavia in the west to the Aral Sea in the east. At the end of the Tertiary period, this basin separated from the Caspian Sea and was reduced to the dimensions of today's Black Sea.

During the Ice Age of the Pleistocene epoch, the level of the Black Sea rose and the sea was connected several times with the Mediterranean and Caspian seas. But in the postglacial period, the Black Sea shrank, became a freshwater sea, and its water level fell below that of the ocean. The Bosphorus Strait was formed 6,000-8,000 years ago. Salt water from the Mediterranean Sea entered the Black Sea and filled its basin. It destroyed the freshwater fauna of the Black Sea, which was replaced by the saltwater fauna of the Mediterranean Sea. Sea levels rose, and salt water flooded the lower reaches of river valleys, creating lime.

The continental shelf is the outer coastal ring, less than 200 m deep. It slopes gently away from the coast and is covered with terrigenous deposits from the mountains. It covers about a quarter of the sea area and is widest in the northwest and in the Kerch Strait.

The continental slope is the ring that separates the continental shelf and the core of the basin. The steepness of the slope usually varies between 5° and 6°. At a depth of about 2,000 m, the steepness of the slope suddenly decreases and the slope merges with the bottom of the basin. The surface of the slope is usually very uneven and covered with a layer of sticky mud, black on top and light gray below. The color is due to ferrous sulfide, which is deposited as very fine grains or fine needles.

There are hardly any islands in the Dnipro-Boh estuary, and the island of Zmiinyi, near the Danube River delta, is small in size.

Climate. The climate of the Black Sea is predominantly continental. Only the southern coast of Crimea and the northwestern coast of Caucasia are protected by mountains from cold northerly winds and are visited by gentle winds from the Black Sea. Therefore, they have a temperate Mediterranean climate. The Atlantic Ocean has a great influence on the climate of the Black Sea. In winter, northeasterly winds generally prevail over the sea, lowering the temperature and causing frequent storms. On the northeast coast, near Novorossiisk, cold and violent mountain winds develop. The temperature of the northern part of the Black Sea averages about -3°C in January, but occasionally drops to -30°C. Coastal waters freeze for a month or more, while shallow bays, river mouths and lemons are frozen for two to three months. During this season, the southern coast of Crimea and the sheltered eastern coast enjoy a temperature of 6-8°C, well above freezing. The average July temperature in the north is 22-23 °C, and in the south - 24 °C. The northwestern coast has the lowest annual precipitation (300 mm), and the Caucasus coast has the highest ( up to 1,500mm).

The waters

The average volume of water in the Black Sea is 547,000 km3. The volume changes according to the following factors: precipitation, which is usually 230,000 km²; the inflow from the mainland - 310,000 cubic km; the flow from the Azov Sea - 25,000 cubic km; evaporation loss: 357,000 cubic km; and exit through the Bosphorus Strait - 208,000 km3.

Due to the relatively young geological age of the Black Sea and the large inflow of freshwater and semi-fresh water from the Sea of ​​Azov, the salinity of the Black Sea is almost 50 percent less than the salinity of the ocean. It is lowest in the Northwest (13 parts per thousand) and rises to 17-18 parts per thousand elsewhere. Salinity also varies: it is lowest at the surface and increases with depth to about 23 parts per thousand at 730 m, beyond which it remains almost constant.

By temperature, the waters of the Black Sea are divided into two unequal layers: the upper layer, which extends to a 

By temperature, the waters of the Black Sea are divided into two unequal layers: the upper layer, which extends to a depth of about 500 m, the lower layer, 500 m to the bottom. The bottom layer maintains a nearly constant temperature of 9°C.

In winter, the temperature of the upper layer increases with depth, and in summer it decreases with depth. Vertical temperature changes are unequal. On the surface, the temperature is lower in February: from -0.5 ° C in the north, where coastal waters freeze 10–20 km from the coast, to 5–8 ° C in the south. The waters reach their highest temperature in August, from 20°C in the north to 25°C or more in the south. In the Sea of ​​Azov, the waters reach 26–27 ° C, and even 30 ° C.

The density of water depends on salinity and temperature. It is lowest at the mouths of rivers and the Kerch Strait (1,010–1,014 g/cc on average) and increases towards the open sea and downwards – it is 1,017 g/cc on average at a depth of 150 m and almost constant below. of that depth.

Oxygen is the most important gas in seawater because it supports organic life. In the upper layer it reaches 4–7 cc per litre. The amount of oxygen decreases rapidly with depth: at 200 m only 0.5 cc is found in a liter of water. This is not enough to support life and therefore only a few bacteria (Microspira aestuarii) live at this depth. Another obstacle to life below 200 m is the high concentration of hydrogen sulfide, which increases to 6–7 cc per liter at a depth of 2,000 m.

The transparency of the water in the Black Sea is 16 to 22 m deep on average. It is lowest near the coast (2–3 m) and highest in the middle of the sea (20–27 m).

Water movements.

The surface of the Black Sea is usually calm, but waves arise in windy weather, particularly in winter. During storms, waves can reach heights of 15 m or more and pose a threat to small boats. The tide is almost imperceptible, since it reaches barely 10 cm in height.

There are two types of sea currents in the Black Sea: the surface currents, caused by the cyclonic pattern of the winds, and the double currents in the Bosphorus Strait and the Kerch Strait, caused by the exchange of waters with adjacent seas. The surface currents form two closed circles. The width of the western circle, facing the Danube Delta, reaches 100 km and decreases towards the south. The speed of the current is about 0.5 km per hour. The width of the eastern circle varies between 50 and 100 km, and the speed is 1 km per hour.

The double current of the Bosphorus Strait consists of the exchange of waters between the Black Sea and the Sea of ​​Marmara. The less saline and clearer waters of the Black Sea flow as a surface current into the Sea of ​​Marmara at a speed of 1 to 2 m per second. In return, the more saline and denser waters of the Sea of ​​Marmara flow at a depth of 50-120 m into the Black Sea at a speed of 4-6 m per second. In the Kerch Strait, the surface current flows from the Sea of ​​Azov to the Black Sea at 1–2 m per second, while the lower current flows in the opposite direction at a depth of about 5 m.

In addition to horizontal currents, there are also vertical currents, which are limited to surface waters up to 200 meters,

Flora and fauna.

The most peculiar feature of the Black Sea is the absence of marine life at depths greater than 150-200 m, except for some anaerobic bacteria. Living organisms are concentrated in the shallow waters of the continental shelf and the mouths of rivers along the northwest coast.

The plant world consists of phytoplankton (350 unicellular species occur), bottom macrophytes (280 species), various species of grasses and seagrasses. The grass Phillophora rubens, which covers more than 15,000 square kilometers of the seabed and is harvested in quantities of more than five million tons, has commercial value. Zostera seagrass, which is eaten by fish, grows on the silt and sand bottoms of calm bays.

The number of animal species in the Black Sea is small compared to the number in the Mediterranean Sea: 350 species of simple creatures, 650 species of crustaceans, more than 200 species of mollusks, about 180 species of fish and 4 species of mammals. (the monk seal and 3 species of dolphins). Mammals and fish are of commercial value. The fishing industry brings rich catches of sturgeon, mackerel, sardine, herring, anchovy, mullet and other fish.

Reference:

http://www.encyclopediaofukraine.com/display.asp?linkpath=pages%5CB%5CL%5CBlackSea.htm 

The Bosphorous, narrowest and busiest strait of the world will have an artificial twin: the Istanbul Canal

The Bosphorus also known as the Strait of Istanbul is a narrow, natural strait which is also a very important waterway located in northwestern Turkey. 

It connects the Black Sea with the Sea of Marmara, and by extensión, via the Dardanelles, the Aegean and Mediterranean seas.

It forms part of the continental boundary between Europe and Asia, and divides Turkey by separating Anatolia from Thrace. 

It is a 31 km long strait with a minimum width of 700 m and maximum depth of 110 m.

Because the Black Sea has a positive water balance, it has a net outflow of water 300 km3 (which drains through the Bosphorous into the Sea of Marmara and the Aegeans Sea. In the strait there is a two-way hydrological exchange: the more saline and therefore denser, but warmer, Mediterranean water flows into the Black Sea under its less saline outflow. This creates a significant anoxic layer well below the surface waters.

The degree of saltiness in the water flowing from the Black Sea is 0.17 % while in the water flowing from the Sea of Marmara into the Bosphorus it is. 0.35%. The average flow through the Bosphorus strait is about 10,000 m3 per second.

Most of the shores of the strait are heavily settled, straddled by the city of Itanbul’s metropolitan population of 16- 17 million inhabitants which is mainly on the European (northern) side of the strait. Metropolitan Istanbul extend inland from both coasts.

The Bosphorus allows maritime connections from the Black Sea all the way to the Mediterranean Sea and the Atlantic Ocean via Gibraltar, and the Indian Ocean through the Suez Canal, making it a crucial international waterway, in particular for the passage of goods coming in from Russia, Ukraine and other Black Sea coastal countries.

There is a  Project that has been promoted by the government of Turkey to build an artificial canal parallel to the Bosphorous and there are plenty of discussion on its convenience, the proposed project is usually called the “Istanbul Canal”.

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Istanbul Canal: Erdogan's dream, Istanbul's nightmare

Turkey's President Erdogan wants to create a second Bosporus. The cost to the economy and environment would be enormous — and that's why Istanbul's mayor is attempting to stop the plan. A bitter power struggle is raging.

    

Turkish President Recep Tayyip Erdogan is well known for his penchant for gigantic construction projects in Istanbul. Be it a new airport, Turkey's largest mosque or a tunnel that goes under the Bosporus — he has built it all within a short time. But these objects of prestige are nothing compared to his latest construction project: The Istanbul Canal.

The Turkish government is planning nothing short of the creation of a second Bosporus — a copy of the strait that meanders through the middle of the 16-million metropolis of Istanbul. To the west of the city, the artificial 45-kilometer canal is to be built parallel to the Bosporus, linking the Black Sea with the Sea of Marmara. According to government sources, the intention is to relieve the heavy shipping traffic on the Bosporus and to avoid accidents.

Planning for the project began as early as 2011, then stagnated for years. But now the Turkish government has brought the plans to life again. Erdogan announced that the tender for the canal construction will soon begin. The Ministry for Environment and Urban Development has examined the environmental compatibility of the construction project and assessed it as "positive."

Opposition from Mayor Imamoglu

But the realization of Erdogan's latest mega-construction project is being hampered by a shift in the balance of power in the Bosporus metropolis in June. Since then, Social Democrat Ekrem Imamoglu of CHP has been mayor — marking the first time in 25 years that Istanbul's mayor is not part of Erdogan's AKP party. And the city's newest leader has made his opposition to the planned construction known. 

Imamoglu calls the project a "betrayal of Istanbul" and a "murder project," and vows that "16 million people will resist." He also took political action by terminating a protocol of cooperation that the previous municipality had agreed with the government.

The rejection by Istanbul's mayor, but also of city residents and scientists, is mainly due to the high construction costs and considerable environmental concerns.

The project could have a significant impact on the region's nature, says environmental expert Doganay Tolunay of Istanbul University. The canal will consume important water resources because Istanbul's water reserves will be stored where it is planned to run. The canal also endangers the region's complex ecosystem. "The dune landscapes in the north of the city are home to protected forests, streams and pastures that are important for the ecosystem and are home to hundreds of species of plants and animals," warns Tolunay. A serious disturbance of the ecosystem could possibly have economic consequences. "Fishermen in the Black Sea and farmers would have to leave the region," he said. 

Mega-project with mega-costs

Added to this are the enormous construction expenses. Officially, the equivalent of €11.5 billion ($12.9 billion) is being talked about. But experts expect the costs for the new canal to be much higher. The largest opposition party, CHP, has criticized the project as being carried out "on the back of the taxpayer."

"The project lacks any economic rationality," says economist Mustafa Sönmez, adding that the Bosporus already guarantees good conditions for shipping and allows sufficient passage.

Earthquake risk?

Critics warn that the canal could have a negative impact on the tectonic fault lines that are deep beneath Istanbul's soil, such as increasing the risk of earthquakes. The Agency for Disaster and Emergency Management, however, disagrees — saying there is no connection between earthquake risks and the construction of the canal. But the statement has done little to convince many city dwellers.

Their fear is highlighted by Imamoglu. He claims that a kind of island is being created between the canal and the Bosporus, with 8 million people "trapped" in an earthquake-prone area by this island location.

The mayor of Istanbul also criticizes the fact that plots of land along the canal have already been sold to Arab investors, including members of royal families. Erdogan's response: "Is that forbidden? If it were Hans and George, nobody would have a problem with it."

'The canal is being built'

Leaders within Erdogan's AKP party repeatedly point out that the construction project is not in the remit of Mayor Imamoglu nor Istanbul's city administration, insisting that the Istanbul Canal is a national project — not a local one. 

For years, Erdogan has described the project as his "dream" — and he shows no signs of relenting to skeptics. "Whether they like it or not, Istanbul Canal is being built," Erdogan says.

"We will not allow people without a vision, who have no goals, no love and hope for our country, to dissuade us from doing so," he vows. "We will never engage with the opposition's malicious agenda because we don't want to waste a single second."
Reference:

https://www.dw.com/en/istanbul-canal-erdogans-dream-istanbuls-nightmare/a-51849822

The Black Sea an unusual geography

The Black Sea is the largest inland located sea which has still regular communication with the world oceans.

This communication takes place through the narrow Bosphorous strait which leads to the Mediterranean Sea which in turn connects it with the Atlantic Ocean.

It has a more or less oval shape. Its longitudinal axis is about 1,150km long, and its latitudinal axis is 611km. The sea surface has an area of 423,000 sq km. The average depth is 1,300m, and the greatest depth is 2,245m. The volume of the Black Sea is 547,000 cu km.

Geological history. The Black Sea is considered to be a residual basin of the Central European Tethys Sea, which existed from the end of the Paleozoic era to the Middle Tertiary period. As a result of alpine orogenic movements in the Triassic period, the Tethys Sea became divided into a series of basins. One of them was Pontus, stretching from Moldavia in the west to the Aral Sea in the east. At the end of the Tertiary period this basin separated from the Caspian Sea and shrank to the dimensions of the present Black Sea.

During the Ice Age of the Pleistocene epoch, the level of the Black Sea rose, and the sea was connected to the Mediterranean and Caspian seas several times. But in the postglacial period the Black Sea contracted, became a freshwater sea, and its water level fell below that of the ocean. The Strait of Bosporus was formed 6,000-8,000 years ago. The salt water of the Mediterranean Sea entered the Black Sea and filled its basin. It destroyed the freshwater fauna of the Black Sea, which came to be replaced by the saltwater fauna of the Mediterranean Sea. The sea level rose, and the salt water flooded the lower parts of the river valleys, creating limans.

The continental shelf is the outer, coastal ring, less than 200m in depth. It slopes gently away from the coast and is covered with terrigenous deposits from mountains. It covers about one-quarter of the sea's area and is widest in the northwest and at the Kerch Strait.

The continental slope is the ring separating the continental shelf and the basin's core. The incline of the slope usually varies between 5° and 6°. At a depth of about 2,000m the incline of the slope suddenly decreases, and the slope merges with the basin bottom. The surface of the slope is usually very uneven and is covered with a layer of sticky mud, black on top and light gray underneath. The color is due to ferrous sulfide, which is deposited in the form of very fine grains or thin needles.

There are scarcely any islands in Dnipro-Boh Estuary, and Zmiinyi Island, near the delta of the Danube River, are tiny in size.

Climate. The climate of the Black Sea is predominantly continental. Only the southern coast of the Crimea and the northwestern coast of Caucasia are protected by mountains from the cold north winds and are visited by the mild winds of the Black Sea. Hence, they have a mild Mediterranean climate. The Atlantic Ocean has a great influence on the climate of the Black Sea. In winter northeast winds usually prevail over the sea, lowering the temperature and causing frequent storms. On the northeastern coast, near Novorossiisk, cold and violent mountain winds develop. The temperature of the northern part of the Black Sea averages about -3°C in January, but it occasionally falls as low as -30°C. The coastal waters freeze up for a month or more, while the shallow bays, river mouths, and limans freeze up for two to three months. During this season the southern coast of the Crimea and the sheltered eastern coast enjoy a temperature of 6-8°C, well above the freezing point. The average July temperature in the north is 22-23°C and, in the south, 24°C. The northwestern coast has the lowest annual precipitation (300 mm), and the Caucasian coast has the highest (up to 1,500 mm).

Sea water. 

The average volume of water in the Black Sea is 547,000 cu km. The volume changes depending on the following factors: precipitation, which is usually 230,000 cu km; the inflow from the continent - 310,000 cu km; the flow from the Sea of Azov - 25,000 cu km; evaporation loss - 357,000 cu km; and outflow through the Strait of Bosporus - 208,000 cu km.

Because of the Black Sea's relatively young geological age and the huge inflow of fresh water from the rive

rs and semifresh water from the Sea of Azov, the salinity of the Black Sea is almost 50 percent lower than the salinity of the ocean. It is lowest in the northwest (13 parts per thousand) and increases to 17-18 parts per thousand elsewhere. The salinity varies also: it is lowest at the surface and increases with depth to about 23 parts per thousand at 730 m, beyond which it remains almost constant.

By temperature the waters of the Black Sea are divided into two unequal layers: the upper layer, which extends to a depth of about 500 m, and the lower layer, from 500m to the bottom. The lower layer maintains an almost constant temperature of 9°C. In winter the temperature of the upper layer increases with depth, and in summer it decreases with depth. The vertical temperature changes are uneven. At the surface the temperature is lowest in February: from -0.5°C in the north, where the coastal waters freeze 10–20km offshore, to 5–8°C in the south. The waters reach their highest temperature in August—from 20°C in the north to 25°C or more in the south. In the Sea of Azov the waters reach 26–27°C, and even 30°C in the limans.

The water density depends on salinity and temperature. It is lowest at the mouths of rivers and the Kerch Strait—1.010–1.014 g/cc on the average—and increases towards the open sea and downward—it is 1.017 g/cc on the average at a depth of 150 m and almost constant below that depth.

Oxygen is the most important gas in the seawater for it supports organic life. In the upper layer it reaches 4–7 cc per liter. The quantity of oxygen decreases rapidly with depth: at 200 m only 0.5 cc is found in a liter of water. This is not sufficient to sustain life, and hence only a few bacteria (Microspira aestuarii) live at this depth. Another obstacle to life below 200 m is the high concentration of hydrogen sulfide, which increases to 6–7 cc per liter at a depth of 2,000 m.

The transparency of the water in the Black Sea is 16–22 m of depth on the average. It is lowest near the shore (2–3 m) and highest at the middle of the sea (20–27 m).

Water movements. The surface of the Black Sea is usually quiet, but waves arise in windy weather, particularly in wintertime. During storms the waves can reach a height of 15 m or more and present a threat to small vessels. The tide is almost imperceptible, for it reaches scarcely 10 cm in height.

There are two types of sea currents in the Black Sea: the surface currents, caused by the cyclonic pattern of the winds, and the double currents in the Bosporus Strait and Kerch Strait, caused by the exchange of waters with adjacent seas. The surface currents form two closed circles. The width of the western circle, opposite the Danube Delta, reaches 100 km and decreases towards the south. The velocity of the current is about 0.5 km per hour. The width of the eastern circle varies between 50 and 100 km, and the velocity is 1 km per hour.

The double current of the Strait of Bosporus consists of the exchange of waters between the Black Sea and the Sea of Marmara. The less saline and lighter waters of the Black Sea flow as a surface current into the Sea of Marmara at a velocity of 1–2 m per second. In exchange the more saline and denser waters of the Sea of Marmara flow at a depth of 50–120 m into the Black Sea at a rate of 4–6 m per second. In the Kerch Strait the surface current flows from the Sea of Azov to the Black Sea at 1–2 m per second, while the lower current flows in the opposite direction at a depth of about 5 m.

Besides horizontal currents there are also vertical currents, which are limited to the surface waters down to 200 m.

Flora and fauna. The most peculiar feature of the Black Sea is the absence of marine life at depths beyond 150–200 m, except for a few anaerobic bacteria. Living organisms are concentrated in the shallow waters of the continental shelf and river mouths along the northwestern coast.

The plant world consists of phytoplankton (350 unicellular species occur), bottom macrophytes (280 species), several grass species, and sea herbs. The Phillophora rubens herb, which covers over 15,000 sq km of the sea bottom and is harvested in quantities of over five million tonnes, has commercial value. The Zostera sea grass, which is consumed by fish, grows on the silt and sand bottoms of quiet bays.

The number of animal species in the Black Sea is small in comparison to the number in the Mediterranean Sea: 350 species of simple creatures, 650 species of crustaceans, over 200 species of molluscs, about 180 species of fish, and 4 species of mammals (the monk seal and 3 species of dolphin). The mammals and fish are of commercial value. The fishing industry brings in rich catches of sturgeon, mackerel, sardine, herring, anchovy, gray mullet, and other fish.

Reference:

http://www.encyclopediaofukraine.com/display.asp?linkpath=pages%5CB%5CL%5CBlackSea.htm