The deepest lake in the world. Okavango River: Dissolving in the desert and giving life to the Lake where no river flows
The area of the Red Sea is 450,000 km², almost 2/3 of the sea lies in the tropical zone.
Volume - 251,000 km³.
According to various estimates, the length (in the direction north - south) ranges from 1932 to 2350 km, width - from 305 to 360 km. The shores are slightly indented, their outlines are mainly predetermined by fault tectonics, and the eastern and western shores are parallel to each other almost along their entire length.
In the bottom topography, the following stand out: a coastal shallow (up to a depth of 200 m), the widest in the southern part of the sea, with numerous coral and bedrock islands; so-called main trough- a narrow depression that occupies most of the seabed, on average to a depth of 1000 m; axial trough - a narrow and deep groove, as if cut into the main trough, with a maximum depth, along different sources, from 2604 to 3040 meters. The average depth of the sea is 437 m.
There are few islands in the northern part of the sea (for example: Tiran Island) and only south of 17 ° N. sh. several groups were formed with numerous islands: the Dahlak archipelago in the southwestern part of the sea is the largest, and the Farasan, Suakin, Khanish archipelagos are smaller. There are also separate islands - for example, Kamaran.
In the north of the sea there are two gulfs: Suez and Aqaba, which connects to the Red Sea through the al-Tiran Strait. A fault passes along the Gulf of Aqaba, so the depth of this bay reaches large values(up to 1800 meters).
The peculiarity of the Red Sea is that not a single river flows into it, and rivers usually carry silt and sand with them, significantly reducing transparency. sea water. Therefore, the water in the Red Sea is crystal clear.
The Red Sea is the saltiest sea in the world's oceans. 1 liter of water here contains 41 g of salts (in the open ocean - 34 g, in the Black Sea - 18, in the Baltic - only 5 grams of salts per liter of water). No more than 100 mm falls over the sea per year precipitation(and even then not everywhere and exclusively in winter months), while 20 times more evaporates in the same time - 2000 mm (this means that every day more than half a centimeter of water evaporates from the sea surface). With the complete absence of water supply from land, this water deficit in the sea is compensated only by the flow of water from the Gulf of Aden. In the Bab-el-Mandeb Strait, there are simultaneously currents entering the Red Sea and leaving it. Almost 1000 km³ more water is brought into the sea every year than is taken out of it. It takes only 15 years for a complete water exchange in the Red Sea.
In 1886, during an expedition on the Russian corvette "Vityaz" in the Red Sea, at a depth of 600 meters, waters with an abnormally high temperature were discovered: 21. The Swedish ship "Albatross" in 1948 also discovered similar waters, moreover, with anomalous high salinity. Finally, the presence of hot metal-bearing brines on great depths ah in the Red Sea was established in 1964 by an expedition on the American ship Discovery, when the water temperature from a depth of 2.2 km was 44 ° C, and its salinity was 261 grams per liter. By 1980, 15 places were discovered on the bottom of the Red Sea with similar waters, which, together with adjacent bottom sediments, are highly enriched in metals:33.
Geological structure and bottom topography
The Red Sea is very young. Its formation began about 25 million years ago, when a crack appeared in the earth's crust and the East African Rift Valley formed. Under the action of centrifugal force, due to the rotation of the Earth, the African plate separated from the Arabian plate, and their turn with the formation of a "spiral" twisting to the northeast, and between them a hole formed in the earth's crust, which gradually, over thousands of years, was filled sea water. The plates are constantly moving - the relatively flat shores of the Red Sea diverge in different directions at a rate of 1 cm per year, or 1 m per century (Kendall F. Haven says that at this rate of expansion, in the next 200 million years, the Red Sea will become as wide as the Atlantic Ocean) - but also at different speeds relative to each other: the movement of the African plate was very slow, while the Arabian plate moved much faster and as a result, the Somali plate began to move east. The spiral movement of the Arabian Plate led to the locking of part vast ocean Tethys, washing Africa, and subsequently the formation of the Mediterranean Sea. This is confirmed by the fact that rocks and minerals characteristic of the Mediterranean Sea are also found in the Red Sea. And the further rotation of the Arabian and Somali plates opened a strait in the south, into which waters poured indian ocean leading eventually to the formation of the Gulf of Aden. The movement of continental plates continued to affect the terrain. To the south, a large segment that broke away from the Arabian Plate eventually closed the gap that formed between the African and Somali plates. The sea dried up here, and a valley formed, known as the "triangle Afar". This region, peculiar in the geological sense, has given scientists a lot of information about the history of the planet and the evolution of mankind. The lowest segment of the "Afar Triangle" is currently slowly submerging under water and eventually will be again below sea level.
The changes, of course, affected not only this local area of the earth's surface. The shift of the Syrian-African fault to the north led to the formation of the Suez Bay. The Arabian and African plates continued to move from different speeds(This difference in speeds was due to the different distance of the plates from the axis of rotation). The inevitable friction between the plates created another valley, much like the bed of the Red Sea. This fault starts from the Strait of Tiran and goes further north to the Gulf of Aqaba, as well as the valleys in which the Dead Sea and the Arava lie. The end point of these valleys is Syria. Incessant tectonic activity shifted the Suez Bay to the north - towards the Mediterranean Sea. Human intervention completed this process in 1869 with the opening of the Suez Canal. The waters of the Mediterranean Sea flowed into the Red Sea, and migration began under aquatic flora and fauna in both directions.
Hydrological regime
The Red Sea is the only body of water on Earth that does not flow into any river.
Strong evaporation of warm water has turned the Red Sea into one of the most salty on the globe: 38-42 grams of salt per liter.
There is an intensive water exchange between the Red Sea and the Indian Ocean. In winter, the Southwest Monsoon Current is established in the Indian Ocean, starting in the Bay of Bengal, passing into the West Current, which branches, and one branch goes north into the Red Sea. In summer, the monsoon current, which begins off the coast of Africa, is joined by a current from the Red Sea in the Gulf of Aden. In addition, there are deep water masses in the Indian Ocean, formed by dense waters flowing from the Red Sea and the Gulf of Oman. Deeper than 3.5-4 thousand meters, bottom water masses are common, formed from Antarctic supercooled and dense salt water the Red Sea and Persian Gulf. .
Climate
The climate on the coast of almost the entire Red Sea is tropical desert, and only the far north belongs to the Mediterranean climate. The air temperature in the coldest period (December-January) during the day is +20-25 °C, and in the hottest month - August, it exceeds +35-40 °C and even sometimes reaches +50 °C. Due to the hot climate off the coast
Wayward Reservoirs
Lost lakes
The lakes are very curious, as if playing hide and seek, now disappearing from the face of the earth, then reappearing. In the spring, thanks to the abundance melt water they overflow, and in the summer they begin to shallow and suddenly completely disappear. In our country there are several such reservoirs - in the area between Onega and White lakes, as well as in Nizhny Novgorod, Novgorod and Leningrad regions. In spring and early summer, these reservoirs are not particularly different from their counterparts. Although if you look closely, in completely calm weather, when the surface of ordinary lakes is calm, it ripples and worries, and closer to the center there is something like a cycle. This is because there are deep funnel-shaped pits at the bottom of the reservoirs, into which, twisting in a spiral, water leaves.
After the flood, when the inflow of melt water weakens, the water level in these lakes drops. They quickly become shallow: first, islands appear and grow, then the bottom is exposed. And finally, there comes a moment when the reservoirs simply disappear. In the driest years, people graze cattle and mow grass in their place.
The most famous of the disappearing reservoirs are Shimozero, Kushtozero and Sukhoe. The first disappears in August, the second - in July, the third - in September. Lake Dry, for example, is reported underground passage with Ilmen, and Kushtozero - with Onega. It used to happen that a pike released in Sukhoi with an earring or a radio sensor was later caught in Ilmen.
Scientists explain the disappearance of such lakes by purely geological reasons. These reservoirs are located in the region of karst caves and feed underground lakes, as well as various springs and springs. Sometimes a collapse occurs at the site of the funnels, and then the “drain” is clogged. In such cases, reservoirs can exist unchanged for several years, but in the end the water still dissolves limestone and dolomite rocks and washes itself new way in the dungeon.
Unusual content
Some of the natural lakes are filled with such unusual contents that one can only be surprised at the vagaries of nature. Take, for example, Lake Trinidad, located fifty kilometers from the northern part of Venezuela, near the settlement of La Brea, and filled with ... real asphalt. The lake is located in the crater of a former mud volcano, its depth is 90 meters, and its area is 46 hectares. Coming out of the bowels of the earth through the mouth of a volcano, oil lying at great depths loses volatiles, resulting in asphalt. All this takes place in the center of the lake basin, in a place called Mother Lake. Up to 150 thousand tons of asphalt, which is used for construction purposes, is mined in the Mother Lake, but its reserves are inexhaustible.
A person can safely walk on the surface of the lake, with the exception of its center, without fear of perishing in a viscous mass. But it is impossible to stay for a long time and linger in one place without moving: the thickness of the asphalt begins to drag on. Any object left on the surface of the lake disappears into the black abyss after a while. Scientists exploring the bowels of an asphalt lake discovered a whole cemetery of prehistoric animals - the bones of mastodons that became extinct in ice Age, and even the remains of ancient lizards.
There are reserves of asphalt in the Dead Sea, famous for its healing properties. Many people know about its extreme salinity and unique composition of water, but not everyone has ever heard of asphalt deposits. Accumulations of asphalt, resembling resin in appearance, from time to time float to the surface and are thrown ashore by waves. Asphalt has been mined in the Dead Sea since ancient times. It is used in various industries: for building roads, tarring ships, obtaining all kinds of chemical products ... Until the middle of the 20th century, it was believed that the area Dead Sea- practically the only supplier of asphalt in the world, and only in the 50s of the last century were new deposits discovered and developed.
The hottest and most explosive
Near the Red Sea, on the Sinai Peninsula, there is one amazing lake. It is separated from the sea by a wide bridge made of petrified shell rock. Marine fish and other representatives of the fauna live in the upper layers of the lake, bluish-green algae grow in shallow water. And the amazing thing about this lake is its temperature. At the surface, the water temperature is almost all year round invariably equal to +16°C, at a depth of 6 meters or more it fluctuates from +48°C in winter to +60°C in summer. Because of this, all living creatures prefer to settle in the upper layer. The upper and lower tiers also differ in salinity: at the top it is 42-43 ppm, and near the bottom it is twice as rich. There are other hot and salty lakes in the world, but none of them has such an amazing vertical distribution of salinity and temperature.
The warmest body of water in the country of eternal frost is in Antarctica. The thickness of the ice covering Lake Vanda is 4 meters. Directly under the ice, the water is fresh, and at a depth it is already salty. Even in the most severe frosts, reaching -50-70°C, the temperature of the water under the ice does not drop below +6°C, and at the bottom (at a depth of 70 meters) it is +25-28°C, as if in some south sea. The most amazing thing is that there are no hot springs at the bottom of this reservoir! Wanda's secret, according to scientists, is that the lake is a kind of giant thermos. Its crystal clear and transparent waters, in which there are no microorganisms, are well warmed up by the sun through the refractive Sun rays ice lens. The warmest are deep waters, which, due to their salinity, greater density and gravity, remain below and do not mix with the upper layers.
The most beautiful lake Bosumtwi is located in the Republic of Ghana, in tropical African forests, 30 kilometers southeast of the city of Kumasi. It is known as the most unpredictable body of water in the world. Bosumtwi has the shape of a regular circle, as if someone had drawn a circle with a gigantic compass and dug a hole here about 400 meters deep and 7 kilometers in diameter. The color of the water in the lake is bluish, in some places along the shores the jungle parted and form glades, on which there are small settlements. Several mountain streams flow into the lake, but not a single river flows out of it. Apparently, therefore, the water level in it is steadily rising, gradually flooding the villages located on the shore. But most of all, Bosumtwi shocks people with his explosive temper. For many months it keeps silence and calm, when suddenly it suddenly explodes: in the depths of it, a giant air bubble seems to burst, huge cascades of water fly up, the surface of the lake boils and rages. Gradually, Bosumtwi calms down.
Because of such explosions, a lot of fish die, and the natives collect prey with nets. Scientists believe that the cause of the explosions are bottom sediments, in which decay occurs. organic matter. The released gases accumulate to the maximum limit, and then violently escape from the bowels of the lake.
For geographers, Bosumtwi is a real mystery. Some researchers believe that the lake was formed as a result of a giant meteorite falling to Earth, others adhere to the hypothesis of an antimatter explosion that did not leave any fragments and debris behind. And finally, the most plausible version is the formation of Bosumtwi as a result of volcanic activity. It is likely that the lake, located in a mountainous region, occupies the bottom of a destroyed volcano cone that existed in ancient times.
Hiding the secret of origin
Lake Mogilnoye, located on Kildin Island near the Kola Peninsula, is considered the most “layered” body of water in the world. The height of the water in it is slightly higher than sea level, despite the fact that it is separated from the sea by only a gravel-sand barrier. reminiscent layered cake the reservoir is divided into five completely independent, not similar friend on the other tiers-floors. The lowest tier, located at a depth of 17-18 meters, is filled with liquid silt. Organic residues coming from the upper floors rot here. This layer is dead, devoid of oxygen, but hydrogen sulfide is present in large quantities there. The only inhabitants of the first tier are some types of bacteria. On the second floor, eternal twilight reigns, the water is saturated with purple-colored bacteria, coloring it in a cherry-pink color. These bacteria actively absorb and oxidize the hydrogen sulfide coming from below, so that the deadly gas does not pass into the upper tiers.
In the third layer from the bottom, life is in full swing. There is on this floor. sea stars, hedgehogs and crustaceans, as well as special kind cod, called Kilda in honor of the island. Fourth floor - transition zone, the water in it is moderately brackish, there are no marine life. But the fifth, uppermost, tier is filled with fresh (!) Water, cold and clear. Numerous inhabitants live there, typical of Arctic reservoirs. Mogilny Lake is one of the oldest. It survived several geological epochs and preserved some species of living creatures that have long disappeared in the neighboring Barents Sea. Researchers still do not know how this lake appeared and why it is divided into layers.
There is also the most lifeless body of water on the territory of Russia, in which, it would seem, there are excellent conditions for the existence of all kinds of living creatures. This is Lake Empty, located in the Kuznetsk Alatau region. All the reservoirs around are teeming with fish, and there is nothing in the Empty, despite the fact that the lakes are connected by rivers. Researchers have repeatedly tried to populate a strange body of water various types fish, giving preference to the most unpretentious, but nothing came of it: the fish did not take root. The empty remains empty. And no one can explain how it arose and why this mysterious reservoir is still devoid of any life.
But the most dangerous body of water on our planet is rightfully considered the Lake of Death, located on the island of Sicily. All its banks and waters are devoid of any vegetation and living creatures, and swimming in it is deadly. Any creature, caught in this terrible lake, instantly dies. It is worth a curious person to stick an arm or leg into the water - and he immediately feels a strong burning sensation, after which, pulling back his limb, he watches with horror how the skin becomes covered with blisters and burns. The chemists who analyzed the contents of the lake were quite surprised. The water of the Lake of Death contains sulfuric acid in a fairly large concentration. On this occasion, scientists have put forward several hypotheses, for example, that the lake dissolves some unknown rocks and is enriched with acids due to this. However, studies have confirmed a different version. It turned out that concentrated sulfuric acid is thrown into the Lake of Death by two sources located at its bottom.
In Algeria, near the city of Sidi Bel Abbes, there is a natural lake filled with real ... ink. It is clear that there are no fish or plants in the reservoir, since the ink is poisonous and is suitable only for writing with it. For a long time, people could not understand how a substance so unusual for a reservoir arises, and recently scientists have finally figured out the cause of this phenomenon. One of the rivers flowing into the lake contains a huge amount of dissolved iron salts, and the other contains all kinds of organic compounds, many of which are borrowed from peat bogs located in the river valley. Merging together into the lake basin, the flows interact with each other, and in the course of constantly occurring chemical reactions ink is produced. Some of local residents consider the black lake to be a diabolical invention, others, on the contrary, try to benefit from it. Therefore, he has half a dozen names. Among the most famous are the Eye of the Devil, the Black Lake and the Inkwell. Well, ink from it is sold in stationery stores not only in Algeria, but also in many other countries.
From the book Inhabitants of the Reservoirs author Lasukov Roman YurievichWhat are the reservoirs Lake A lake is a resting or slowly flowing significant body of water in a natural depression of land that does not have direct contact with the sea. Stratification of lakes. Stratification is the formation of layers of water with different densities and
From the author's bookTemporary reservoirs Temporary reservoirs include small accumulations of water that occur periodically and disappear relatively quickly. They are formed in the depressions of the land after the snow melts, the recession of the flood waters of the river, or as a result of the accumulation of rain
As you know, 71 percent of our Earth's surface is covered with water. From space, our beloved planet looks like a blue ball because bodies of water reflect the sun's rays in the blue spectrum.
Photos from spacecraft NASA is showing us a magnificent view of the marble-blue Earth from space. In our world there are many beautiful rivers, lakes, impressive waterfalls, stunning glaciers and clear waters surrounded by snowy mountains. Fortunately, each of us can see all these magnificent creations of nature.
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10Suez Canal, Egypt
160 kilometers long, 300 meters wide - this is the size of this artificial waterway that connects the Mediterranean to the Red Sea. The Suez Canal is considered the shortest route between Europe and Asia. This makes shipping and trading much easier, cutting down on complicated routes around Africa. Currently, the Suez Canal is one of the busiest waterways in the world, while it has experienced far fewer accidents than other similar structures.
The construction of the Suez Canal took a total of 10 years. Starting in 1859, ships from all countries were already able to pass through the Suez Canal, carrying cargo along the Europe-Asia route. The Suez Canal's advanced radar control system monitors every ship passing through. In emergency situations, this system allows the rescue services to respond immediately, thereby reducing the risks to ships passing through the canal.
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9Bora Bora, France
Bora Bora is one of the most beautiful places in the world for international tourism. This group of islands is a territorial part of France and is located in the Pacific Ocean. Bora bora are white sandy beaches, blue lagoons and glamorous resorts, which are invariably popular with vacationers.
Currently, it is tourism that supports the entire economy of the island. Glazed comfortable villas turn this place into a tourist paradise. Snorkeling and diving in crystal clear waters attract thousands of people who want to enjoy the beauty water element and relax on the sunny beaches of Bora Bora.
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8Lake Baikal, Siberia
Lake Baikal is the oldest and deepest lake in the world. It is located in South-Eastern Siberia. The lake has a depth of 1700 m, and was formed 25 million years ago from the present prehistoric sea. 20 percent of the total volume of fresh water in the world is contained in Baikal. Around the lake there are picturesque nature reserves protected by the government. Clean and beautiful Baikal is included in the UNESCO World Heritage List.
In the Baikal region, there are many cultural, archaeological and historical treasures. The surroundings of the lake are home to 1340 animal species. Many of them are unique and are found only in the Baikal region. Ancient mountains, mighty taiga and small islands make the Baikal region one of the most biologically diverse places in the world.
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7Great Blue Hole, Belize
This is a large natural underwater sinkhole, located 70 kilometers above sea level, in the middle of a barrier reef in Belize. Its huge funnel is 120 meters deep and 300 meters in diameter. It was formed during the Ice Age, 150,000 years ago, before the glaciers were completely gone. The gradual melting of ice and rising sea levels just caused the formation of this miracle of nature.
The Great Blue Hole became a World Heritage Site in 1997. More than 500 rare forms of animals and plants live here. Every year, this natural sinkhole attracts many tourists from all over the world who come here, mainly for scuba diving.
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6
Venice is a group of 117 small islands separated by canals and connected by bridges. The canals divide the city into 117 small cozy islands. It is these waterways from time immemorial that have been used as the main transport network in Venice. The Grand Canal, the city's main waterway, is the largest canal in Venice, 3.8 km long and 60 to 90 meters wide.
The Grand Canal tour is the best way to explore Venice while gaining in-depth knowledge of the city's historical importance. For large tours of Venice, gondolas, traditional punts, and more modern motor boats are mainly used. You can take a closer look at the beauty of historical buildings, palaces, churches and see the famous century-old Rialto Bridge.
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5Dead Sea, Jordan
The Dead Sea is one of the saltiest bodies of water in the world, located on the border of Israel and Jordan. The salinity of the Dead Sea ranges between 34-35 percent on average. This is almost ten times more than ordinary salty sea water. The increased salt content in the water is the reason for the complete absence of aquatic flora and fauna, which is why this lake is called the "Dead Sea". The lake is located 423 meters below sea level, and is the lowest place on land.
Such a high concentration of salt allows tourists to effortlessly swim in the Dead Sea, almost without moving their limbs. This water benefits human health because it contains a large number of useful minerals such as potassium, calcium, sulfur and bromine. The Dead Sea can cure various skin conditions and help you get rid of toxins. It is said that Dead Sea minerals were transported to Egypt in ancient times, where they were used to mummify Egyptian pharaohs.
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4
Neil is the most long river in our world, having an approximate length of 6650 kilometers. It starts in Burundi and passes through Kenya, Eritra, Congo, Uganda, Tanzania, Rwanda, Egypt, Sudan and Ethiopia, where it meets the waters of the Mediterranean Sea. The Nile played a very important role in the life of the ancient Egyptians.
The river was the main source of food, water and a waterway for transporting goods between countries. At the same time, when, as a result of seasonal rains, the Nile overflowed its banks, all the lands of Egypt were flooded with water for for a long time. This helped the ancient Egyptians easily grow the seeds of cultivated plants.
All historical monuments Egypt, including the pyramids are located near the banks of the Nile. The Nile Delta covers an area up to 160 kilometers wide and as many as 40 million people live around using the waters of the sacred river.
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3Niagara Falls, United States of America
Niagara Falls is on the border between Canada and the United States. Niagara is made up of three waterfalls, American Stream, Bridlevale and Horseshoe. These three waterfalls together create a flow of water of 85,000 feet per second. This is the highest flow of water in the world. "Horseshoe" is the largest of the three Niagara Falls and most of it, located closer to Canada. "American Stream" and "Bridalveil" are located in the United States.
Niagara was formed 10,000 years ago during the Wisconsin glaciation. The brilliant green color of the water of Niagara Falls is due to the mixing of salt and rocks with water at high speed. The whirlpool created by Niagara Falls has an area of 1.2 kilometers. Its depth is the same as the height of Niagara, and is 52 meters. Water from Niagara flows into Lake Ontario in the Canadian province.
Amazing video of Niagara Falls:
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2Victoria Falls on the border of Zambia and Zimbabwe
Victoria Falls is the largest waterfall in the world and is one of the seven natural wonders Sveta. It is located on the Zambezi River between the states of Zambia and Zimbabwe. The Victoria Falls are over a mile wide and provide five hundred million drops of water. cubic meters per minute. The water falls to a depth of 93 meters and is strongly sprayed, breaking on the rocks. Because of this water cloud, the Victoria Falls are visible at a distance of 50 kilometers to the naked eye.
Strong water spray causes constant rain in the forests surrounding the falls. Surprisingly, on the edge of the waterfall you can swim without much risk. Natural stone ledge will not let you fall down with the water. This pool is known as the Devil's Pool. During the full moon at Victoria Falls, one of the most magnificent natural phenomena known as the "Moon Rainbow" occurs. A beautiful rainbow is visible at this time above the waterfall, in the bright light of the moon refracted by water spray.
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1Great Barrier Reef, Australia
The Great Barrier Reef is the largest coral reef in the world, one of the seven natural wonders of the world. These are 900 islands connected together with a length of more than 2300 kilometers. The reef is large enough to be seen from space and is recognized national symbol Australia. The Great Barrier Reef contains over 3,000 individual reefs built by microorganisms over millions of years. It was included in the UNESCO World Heritage List in 1981.
The Great Barrier Reef gives life to a huge variety marine life and fauna. About 1,500 species of fish, 3,000 species of molluscs, 500 species of worms, 133 species of sharks and rays, and 30 species of whales and dolphins live there. The tourism industry is very developed here. Glass-bottom boat tours, exciting snorkeling and kayaking are very popular with vacationers. The Great Barrier Reef attracts about 2 million visitors each year.
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Conclusion
Red sea- the inland sea of the Indian Oceanlocated between the Arabian Peninsula and Africa in a tectonic depression. One of the warmest and saltiest seas.
Washes the shores of Egypt, Sudan, Ethiopia, Eritrea, Saudi Arabia, Yemen, and Jordan.
Resorts: Hurghada, Sharm el-Sheikh, Safaga, El Gouna (Egypt), Eilat (Israel)
The Red Sea is connected to the north by the Suez Canal. mediterranean sea, in the south - the Bab el-Mandeb Strait with the Arabian Sea.
The peculiarity of the Red Sea is that not a single river flows into it, and rivers usually carry silt and sand with them, significantly reducing the transparency of sea water. Therefore, the water in the Red Sea is crystal clear.
The climate on the Red Sea coast is dry and warm, the air temperature in the coldest period (December-January) during the day is 20-25 degrees, and in the hottest month - August, does not exceed 35-40 degrees. Due to the hot climate off the coast of Egypt, the water temperature even in winter does not drop below +20 degrees, and in summer it reaches +27.
strong fumes warm water turned the Red Sea into one of the saltiest on the globe: 38-42 grams of salt per liter.
The length of the Red Sea today is 2350 km, the width is 350 km (in its widest part), the maximum depth reaches 3000 meters in its central part. The area of the Red Sea is 450 thousand sq. km.
The Red Sea is very young. Its formation began about 40 million years ago, when a crack appeared in the earth's crust and the East African Fault was formed. The African continental plate separated from the Arabian one, and between them in the earth's crust a pit was formed, which was gradually filled with sea water over thousands of years. The plates are constantly moving, so the relatively flat shores of the Red Sea diverge in different directions at a rate of 10 mm per year, or 1 m per century.
In the north of the sea there are two bays: Suez and Aqaba, or Eilat. It is along the Gulf of Aqaba (Eilat) that the fault passes. Therefore, the depth of this bay reaches large values (up to 1600 meters). The two bays are separated from each other by the Sinai Peninsula, in the south of which is the famous resort of Sharm el-Sheikh.
There are few islands in the northern part of the sea, and only to the south of 17°N. they form numerous groups, the largest of them is Dahlak in the southwestern part of the sea.
The Red Sea is located between Africa and the Arabian Peninsula. It occupies a deep, narrow, long depression with steep, sometimes sheer slopes. The length of the sea from northwest to southeast is 1932 km, the average width is 280 km. The maximum width in the southern part is 306 km, while in the northern part it is only about 150 km. Thus, the length of the sea is about seven times its width.
The area of the Red Sea is 460 thousand km 2, the volume is 201 thousand km 3, the average depth is 437 m, greatest depth- 3039 m.
In the south, the sea connects with the Gulf of Aden and the Indian Ocean through the narrow Bab el-Mandeb Strait, in the north - the Suez Canal with the Mediterranean Sea. The smallest width of the Bab el-Mandeb Strait is about 26 km, the maximum depth is up to 200 m, the depth of the threshold from the Red Sea is 170 m, and in the southern part of the strait - 120 m. Due to limited communication through the Bab el-Mandeb The Red Sea Basin is the most isolated basin in the Indian Ocean.
Suez Canal
The length of the Suez Canal is 162 km, of which 39 km passes through the salt lakes Timsakh, Big Gorky and Small Gorky. The width of the channel on the surface is 100-200 m, the depth along the fairway is 12-13 m.
The shores of the Red Sea are mostly flat, sandy, sometimes rocky, with sparse vegetation. In the northern part of the sea, the Sinai Peninsula separates the shallow Gulf of Suez and the deep, narrow Gulf of Aqaba, separated from the sea by a threshold.
There are many small islands and coral reefs in the coastal zone, the largest islands are located in the southern part of the sea: Dahlak off the African coast and Farasan off the Arabian coast. In the middle of the Bab-el-Mandeb Strait rises about. Perim dividing the strait into two passages.
Bottom relief
In the relief of the bottom of the Red Sea, a shelf is clearly distinguished, the width of which increases from north to south from 10-20 to 60-100 km. At a depth of 100-200 m, it gives way to a steep, well-defined ledge of the continental slope. Most of the Red Sea depression (main trough) lies in the depth range from 500 to 2000 m. Numerous seamounts and ridges rise above the undulating bottom plain, in some places a series of steps parallel to the margins of the sea can be traced. A narrow deep groove runs along the axis of the depression - an axial trench with maximum depths for the sea, which is the median rift valley of the Red Sea.
Brine depressions in the Red Sea
In the 60s. in the central part of the axial trench, at depths of more than 2000 m, several depressions were discovered with hot brines, which have a peculiar chemical composition. The origin of these depressions is related to the fact that modern tectonic activity is actively manifested in the rift zone of the Red Sea. Over the past decades, more than 15 depressions have been discovered in the axial zone of the sea, containing highly mineralized brines with a salinity of 250‰ or more. The temperature of brines in the hottest basin, Atlantis-II, reaches 68°.
Bottom relief and currents of the Red Sea
Climate
Meteorological conditions over the sea are formed under the influence of the following stationary and seasonal baric centers of the atmosphere: high blood pressure over North Africa, Central African region reduced pressure, centers of high pressure (in winter) and low pressure (in summer) over Central Asia.
The interaction of these baric systems determines the predominance in the summer season (from June to September) of northwestern winds (3-9 m/s) over the entire length of the sea. In the winter season (October to May) in the southern part of the sea from the Bab-el-Mandeb Strait to 19-20°N. southeasterly winds prevail (up to 7-9 m/s), and to the north weaker winds persist northwest winds(2-4 m/s). This wind regime in the southern part of the Red Sea, when they change direction twice a year, is associated with monsoon circulation over the Arabian Sea. The direction of stable wind flows, mainly along the longitudinal axis of the Red Sea, is largely determined by the mountainous relief of the coasts and adjacent parts of the land. In the coastal areas of the sea, daytime and nighttime breezes are well developed, associated with a large daily heat exchange between the land and the atmosphere.
Storm activity in the sea is poorly developed. Most often, storms are observed in December - January, when their frequency is about 3%. In the remaining months of the year, it does not exceed 1%; storms occur no more than 1-2 times a month. In the northern part of the sea, the probability of storms is greater than in the southern part.
Location of the Red Sea in the continental zone tropical climate determines a very high air temperature and its great seasonal variability, which reflects the thermal influence of the continents.
The air temperature during the year over the northern part of the sea is lower than over the southern. In winter, in January, the temperature rises from north to south from 15-20 to 20-25°. In August average temperature in the north 27.5°, and in the south 32.5° (the maximum reaches 47°). The temperature conditions in the southern part of the sea are more constant than in the northern part.
There is very little atmospheric precipitation over the Red Sea and its coast - in general, no more than 50 mm per year. Rainfall is mainly in the form of downpours associated with thunderstorms and occasional dust storms.
The amount of evaporation from the sea surface on average per year is estimated at 200 mm or more. From December to April, evaporation in the northern and southern parts of the sea is greater than in the central part; in the rest of the year, there is a gradual decrease in its value from north to south.
Hydrology and water circulation
The variability of the wind field over the sea plays leading role in level changes from season to season. The range of intra-annual level fluctuations: 30-35 cm in the northern and central parts sea and 20-25 cm in the south. The level position is highest in the winter months and lowest in the summer. At the same time, in the cold season, the level surface is inclined from the central region of the sea to the north and south; in the warm season, the level slopes from south to north, which is associated with the regime of prevailing winds. In the transitional months of the monsoon change, the level surface of the sea approaches the horizontal.
The northwest winds prevailing throughout the sea in summer create a surge along the African coast and a surge near the Arabian coast. As a result, the sea level off the African coast is higher than that of the Arabian coast.
The tides are mostly semi-diurnal. At the same time, level fluctuations in the northern and southern parts of the sea occur in antiphase. The tide decreases from 0.5 m in the north and south of the sea to 20 cm in its central part, where the tide becomes daily. At the top of the Gulf of Suez, the tide reaches 1.5 m, in the Bab el-Mandeb Strait - 1 m.
An important role in the formation of the hydrological regime of the Red Sea is played by water exchange through the Bab el-Mandeb Strait, the nature of which changes in different seasons.
In winter, a two-layer structure of currents is usually observed in the strait, in summer - a three-layer one. In the first case, the surface current (up to 75-100 m) is directed to the Red Sea, and the deep current is directed to the Gulf of Aden. In summer, the drift surface flow (up to 25-50 m) is directed to the Gulf of Aden, going below this layer, the intermediate compensatory flow (up to 100-150 m) - to the Red Sea, and the near-bottom drain - also to the Gulf of Aden. During periods of wind change, multidirectional currents can be simultaneously observed in the strait: near the Arabian coast - into the Red Sea, and near the African coast - into the Gulf of Aden. The maximum drift flow velocities in the strait reach 60–90 cm/s, but with a certain combination with tides, the flow velocity can sharply increase to 150 cm/s and decrease just as quickly.
As a result of water exchange through the Bab el-Mandeb Strait, on average, about 1000-1300 km 3 more water flows into the Red Sea per year than it goes into the Gulf of Aden. This excess of sea water is spent on evaporation and replenishes the negative fresh balance of the Red Sea, where not a single river flows.
The circulation of water in the sea differs significantly seasonal variability, determined mainly by the nature of the steady winds in winter and summer periods. However, the field of prevailing currents is not a simple longitudinal transport along the major axis of the sea, but a complex eddy structure.
In the extreme northern and southern parts of the sea, tides have a great influence on the currents; in the coastal zone, they are influenced by the abundance of islands and reefs, the indentation of the coast. Strong breezes blowing from land to sea and from sea to land also cause circulation disruption. Depending on the area and time of year, the direction of currents along the axial basin of the sea is 20-30%. Quite often there are currents going against the monsoon wind flow or in the transverse direction. The speed of most currents is not more than 50 cm/s, and only in rare cases - up to 100 cm/s.
In the winter season, the circulation on the surface in the northern part of the sea is characterized by a general cyclonic movement of waters. In the central part of the sea, approximately at 20°N. a zone of convergence of currents is distinguished. It is formed at the junction of the northern cyclonic gyre and the anticyclonic gyre, which occupies the southern part of the sea. From the north along the African coast, surface Red Sea water enters the convergence zone, and from the southern part of the sea - transformed Aden water, which leads to water accumulation and level rise in the central part of the sea. In the convergence zone, there is an intensive transfer of water from the western coast to the eastern. Beyond the convergence zone, Aden water moves north, already against the current wind, along east coast. The vertical structure of currents in winter is characterized by their rather rapid attenuation with depth.
In the summer season, under the influence of stable northwestern winds covering the entire sea, the intensity of circulation increases, and its main features are manifested in the entire layer of surface and intermediate waters. In the northern and central parts of the sea, against the background of a rather complex cyclonic structure, water transfer to the Bab el-Mandeb Strait predominates, contributing to their accumulation in the south and lowering in the center of the anticyclonic circulation, which intensifies in summer.
The zone of convergence of currents in the central part of the sea with a uniform wind field is not expressed. At the southern boundary of the sea, in contrast to the winter season, the outflow of waters into the Bab el-Mandeb Strait is traced. Consequently, the movement of waters in a southerly direction prevails throughout the water area. The subsurface transformed Aden waters spread to the north in a complex way, being involved in cyclonic gyres, mainly along the eastern coast of the sea.
The circulation of deep waters is determined by the non-uniformity of the density field. The formation of these waters, as shown below, occurs in the northern part of the sea as a result of convective mixing.
The hydrological structure of the Red Sea - one of the most isolated Mediterranean basins - is shaped mainly by local factors. Among them, the most important are the processes of interaction between the sea and the atmosphere (especially cooling and evaporation, causing convection), the wind, which creates the circulation of waters in the upper layer of the sea, which is characteristic of the winter and summer seasons, and determines the conditions for the inflow and distribution of Aden waters. Water exchange with the Gulf of Aden does not directly affect the structure of the deep layers of the sea due to the shallowness of the strait and the lower density of inflowing waters compared to the Red Sea. At the same time, the features of the upper layer of the sea are closely related to the distribution and transformation of the Aden waters. The most complex (especially in summer) is the structure of the upper 200-meter layer in the south of the Red Sea due to the influence of Aden waters. On the contrary, the distribution of hydrological characteristics in the northern part of the sea is quite homogeneous, especially in winter, during the period of active development of convective mixing.
Water temperature and salinity
Water temperature and salinity at the surface of the Red Sea in summer
The temperature on the sea surface during the cold season rises from 18° in the Gulf of Suez to 26-27° in the central part of the sea, and then drops slightly (to 24-25°) in the area of the Bab el-Mandeb Strait. Salinity on the surface decreases from 40-41‰ in the north to 36.5‰ in the south of the sea.
The main feature of the hydrological conditions in the upper layer of the sea in winter is the presence of two counterflows of water with different characteristics. The relatively cold and more saline waters of the Red Sea move from north to south, and the warmer, less saline waters of Aden move in the opposite direction. The main interaction of these waters takes place in the region of 19-21°N, but due to low salinity, Aden waters stand out in the northern part of the sea along the Arabian coast to 26-27°N. In this regard, a latitudinal unevenness is created in the distribution of hydrological characteristics: in the direction from the African coast to the Arabian coast, the temperature rises slightly, and salinity decreases. In the sea, transverse circulation is excited, accompanied by vertical movements of water in coastal zones.
Water temperature (°С) on a longitudinal section in the Red Sea in summer
In the warm season, the temperature on the surface rises from north to south from 26-27 to 32-33°, and salinity decreases in the same direction from 40-41 to 37-37.5‰.
When north-western winds are established over the entire sea, the spread of high-salinity waters to the south in the surface layer increases and the influence of Aden waters weakens, which leads to an increase in salinity at the entrance to the strait. At the same time, Aden waters with lower temperature and salinity are actively spreading in the subsurface layer to the north. These processes exacerbate vertical temperature gradients, especially in the southern part of the sea.
The exchange of water in the upper layers of the sea is facilitated by the development of transverse circulation. The nature of the prevailing winds in the summer season is such that it often causes the water to sink near the African coast and rise near the Arabian coast, although in some areas, due to compensatory movements, the opposite picture is also possible. In the winter season, the winds in the southern part of the sea cause a surge at the entrance to the Bab el-Mandeb Strait and a rise to the surface of the waters from the intermediate and even from the deep layers of the sea.
Seasonal changes in hydrological characteristics cover the upper layer of the sea with a thickness of 150-200 m. The layer up to 20-30 m is well mixed and uniform throughout the year. The largest vertical gradients of temperature and salinity are observed between the horizons of 50-150 m. The sea column deeper than 200-300 m is highly homogeneous. The temperature here remains within 21.6-22°, salinity - 40.2-40.7‰. These are the highest temperatures and salinity of the deep waters of the World Ocean. The share of the deep Red Sea water accounts for at least 75% of the sea water volume.
The formation of deep water occurs in winter in northern regions seas, when, with a decrease in water temperature by 4-6 °, winter vertical circulation actively develops here, reaching great depths. The formation of deep waters is enhanced by the "shelf effect" - sinking into the deep layers of high-density waters formed in the Gulf of Suez.
Salinity (‰) on a longitudinal section in the Red Sea in summer
According to the set of features in the Red Sea, the following main water masses are distinguished: transformed Aden, surface, intermediate and deep Red Sea.
The transformed Aden water mass has two modifications. In winter, it is released in the 0-80 m layer, in summer it enters the sea as an intermediate flow in the 40-100 m layer. In the southern part of the sea, it has a temperature of 24-26 ° and a salinity of 37-38.5‰.
The surface water of the Red Sea occupies a layer of 50-100 m, depending on the location and season, its temperature varies from 18-20 to 30-31 °, and salinity - from 38.5 to 41‰.
Intermediate Red Sea water is formed in the northern part of the sea as a result of winter vertical circulation and spreads in the 200-500 m layer to the southern part of the sea, where it rises in the 120-200 m layer before the strait. In the northern part of the sea, its temperature is 21.7-22 °, salinity - about 40.5‰, in the south - respectively 22-23 ° and 40-40.3‰.
Deep water is also formed in the north of the sea by convective mixing. It occupies the main volume of the sea in the layer from 300-500 m to the bottom and differs very much. high temperatures(about 22°) and salinity (more than 40‰.
Deep water spreads in a southerly direction and can be traced along the temperature minimum (21.6-21.7°) in the 500-800 m layer. In summer, the temperature minimum stands out almost along the entire sea. In the bottom layer, there is a slight increase in temperature and salinity, presumably associated with the influence of hot brines that fill deep-water basins. The question of the interaction of brines with sea waters has not yet been studied enough.
Fauna and environmental issues
The wealth of life in the Red Sea
More than 400 species of fish live in the waters of the Red Sea. However, only 10-15 species are of commercial importance: sardines, anchovy, horse mackerel, Indian mackerel, from bottom fish - saurid, rock perch. Fishing is predominantly of local importance.
The ecological situation in the Red Sea, as in many areas of the ocean, has recently deteriorated as a result of economic activity person. On the biological resources The growing pollution of the sea with oil has a negative effect; the largest number of oil slicks for the Indian Ocean has been recorded on its surface. The increase in the level of pollution is associated with an increase in shipping, including sea transportation of oil, as well as with the development of oil fields on the shelf of the northern part of the sea.
Oil platform on the shelf of the Red Sea