All water in the world is called the World Ocean. The sea is a part of the world's ocean, a huge salty body of water, which is isolated by land or conditional elevations of the underwater relief. Each sea has a different climatic and hydrological regime, has its own flora and fauna.
Classification of the seas
Modern science uses several classifications of the seas:
- By isolation... There are intercontinental and inter-island, marginal and inland seas,
- By temperature... Distinguish between polar, temperate and tropical,
- By the salinity of the waters... The seas are divided into lightly and highly salted,
- By ruggedness coastline ... Distinguish between weakly and strongly cut line of the coast. This classification is very arbitrary, since some seas do not have a coastline at all, for example, Sargassovo,
- Oceanic... There are 4 oceans in the world - the Pacific, Atlantic, Indian and Arctic (although in Lately many geographers single out South ocean). Each sea is conventionally referred to as a basin of one of the oceans.
How many seas are there in the world?
So how many seas are there in the world? It is not easy to answer this question, since science has identified several classifications. Besides Caspian, Aral, Galilee, Dead many know how the seas, but they are actually referred to as lakes. There are also some bays, which would be more logical to refer to the seas. Small seas that are part of large ones, moreover, are often not taken into account. For instance, Mediterranean Sea consists of 7 inland reservoirs, you can swim from one reservoir to another on a ship without obstacles, but at the same time remain on the territory Mediterranean Sea.
In general, there are 94 seas on Earth.... Of them
- Atlantic Ocean owns 32 seas, for example, Marmara, North, Aegean, Baltic.
- The Pacific Ocean- 30 seas, such as the Yellow, Bering, Japanese, Okhotsk
- Pools Arctic Ocean belongs to 13 seas, such as the Kara, Barents, White, Chukchi
- South ocean also has 13 seas, for example, Cosmonauts, Ross, Lazarev. Indian Ocean - 6 seas, among them the Red Sea is considered the largest.
- Indian Ocean- 6 seas, among them the Red Sea is considered the largest.
Important! To date, the International Geographic Community has adopted 54 seas, without taking into account bays and inland seas..
The Mediterranean Sea is considered the dirtiest, since at least 500 tons of various oil products enter it annually. Moreover, a great danger to the flora and fauna of the Mediterranean Sea is provided by plastic waste, which literally flooded the coastal territories.
The most dangerous sea is the Marmara Sea, which is located on the border of Asia and Europe and serves as a junction of the Aegean and Black Seas. The Sea of Marmara was formed by a fault, subsequently filled with water, it sometimes has more than 1300 meters of depth. The danger is provided by frequent earthquakes and tsunamis. It is believed that this sea has been disturbed by earthquakes at least 300 times.
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The oceans and seas of the Earth are the theme of our story. The oceans are divided into large parts - the oceans: Atlantic, Pacific, Indian, Arctic. Previously, the Southern Ocean, located around Antarctica, was also added to them, but now scientists have divided these waters between three other oceans. It was too inconvenient to look for the border beyond which the Southern Ocean ended and others began!
Earth's oceans and seas - boundaries
Indeed, the rest of the oceans can be separated from each other at least by a map. The Pacific Ocean is connected to the Arctic by only a narrow strait - the Bering Strait, along which the border passes. She is a little wider at The Pacific with the Atlantic - along the Strait of Magellan and Drake Passage, but it is also clearly visible.
The Indian Ocean was not so lucky, it has a natural "fence" from its neighbors only in the east, and even then it is not complete: it passes through the islands of Indonesia, across Australia, and already south of the island of Tasmania there is nothing at all. Therefore, I had to draw a conditional line from Tasmania to the south to Antarctica itself. The same conventional line runs from southern edge Africa and separates the Indian Ocean from the Atlantic.
And here is the border Atlantic Ocean with the North Arctic is noticeable well, but not immediately and not on every map. Only on the one where the sea depths are indicated in different shades of blue and light blue - the lighter, the shallower.
A light strip of shallow depths runs from Norway to the Faroe Islands (just north of Great Britain), then to Iceland and to the largest island in the world, Greenland, covered with an ice cap.
Further, the boundary of the oceans does not pass across the strait, as usual, but along - this is the Hudson Strait between the Canadian coast and Baffin Island. The Great Hudson Bay is considered part of the Atlantic, and all waters to the north are referred to as the Arctic Ocean.
Earth's oceans and seas - the size of the oceans
Most big ocean- Quiet. Previously, it was also called the Great, and this is not surprising: it occupies almost the same area - 180 million km - like all the other oceans together! On such a huge territory, all continents and islands could be accommodated, and there would be quite a lot of free space. This ocean is also the deepest, because its average depth- neither more nor less - 4280 m.
The smallest and shallowest ocean is the Arctic. It fully justifies its name - in winter, almost all of its surface is covered with ice. In summer, the boundary of the ice fields moves closer to the pole, and a strip appears along the continental shores of this ocean with respect to pure water through which ships can pass. But to go across the entire ocean across, across the pole, is possible only under water (more precisely, under ice) or on the most powerful icebreakers - atomic.
Earth's oceans and seas - how much water
The oceans share almost all the water in the world. After all, most rivers flow into the sea - independently or by joining a more powerful stream. Thus, Siberian rivers flow into the seas of the Arctic Ocean, European rivers flow into the Atlantic. The part of the continent from which any ocean is replenished with water, scientists call the drainage zone of this ocean.
Caspian Sea
However, there are also such places that do not want to share moisture with others - closed drainage zones that do not have communication with the oceans. For example, the Caspian Sea - the world's largest lake - in prehistoric times was connected with the World Ocean, but then lost this connection, separated and now "uses" the Volga and many other rivers alone.
In general, the Caspian is the strangest of the seas. Or is it from the lakes? According to strict geographical rules, the sea is a part of the ocean, which is separated from it by land or seamounts - shoals, ridges, chains of islands. Each sea differs in some way from its neighbors - for example, in temperature or salinity of water, but it is also similar to them. Still, relatives, descended from the same ocean. And the Caspian?
The water in it is sea water: the same salty, and in composition it is similar to the ocean water. In ordinary salt lakes, there can be the same substances, but only in different proportions: some are more, and some are not at all. The Caspian Sea has retained the composition that it inherited from its father, the ocean. But from which ocean did it separate?
If you look at the map, everything is almost clear: the Black Sea is nearby, very close to it, and there is a suitable depression on land - Kumo-Manychskaya. Many scientists believe that it was at this place that there was once a strait. So the Caspian is a descendant of the Atlantic, isn't it?
"Not this way!" - said other scientists. If the Caspian Sea simply separated from the Black Sea, then the same fish would have to be found in them, and other animals. But it turns out just the opposite: dolphins live in the Black Sea, and there are no dolphins in the Caspian Sea, but there are seals.
In the Black Sea, Atlantic fish such as sardine and red mullet are caught, but there are almost no sturgeon fish for which the Caspian is famous. But there are many sturgeons in Siberian rivers ... On the other hand, there are still fish common to both seas ...
History of the seas of the Earth
Several million years ago, neither the Caspian nor the Black Seas existed, but there was a huge, larger than the current Mediterranean, Sarmatian Sea. Of course, no one in those days called him that - simply because there was no one to call him. The man has not yet appeared. But today, scientists have given this sea the name of one of the ancient peoples. And they found out that sea waves could walk in the vastness from the Aral Sea to modern Hungary and Austria. The Caucasus and Crimean mountains were then a long chain of large islands, and the Carpathians were a peninsula, somewhat reminiscent of Italy in shape.
This sea was not very salty: many rivers flowed into it, and straits into other seas at different times appeared and disappeared. Living creatures have adapted to brackish water and frequent entry into rivers, and the inhabitants of the ocean did not penetrate into the Sarmatian Sea. However, over time, the land began to gradually rise - mainly in the Caucasus and the Balkan Peninsula.
Gradually, two large depressions, or depressions, as they are also called, were formed - the Black Sea and the Caspian-Aral. They then connected with each other and with the Mediterranean Sea, then separated again. And then the great glaciation began: the climate got colder and a huge glacier advanced from the north, covering almost half of Eurasia. All Siberia, northern Europe was under a kilometer thick layer of ice ...
Not all animals of the Sarmatian Sea have adapted to the cold, many species have become extinct. But warming came, the glacier melted, retreated to the north, new hills, rivers and lakes were formed ... and the level of the World Ocean rose. The Black Sea finally got a permanent connection with the Mediterranean, and the Caspian Sea separated from the Aral.
But in parting, the glacier made these seas an interesting "gift", Through the rivers and lakes formed during the melting ice mountains, some animals that had previously lived in the Arctic Ocean basin got into them. It is believed that it was then that seals and some fish species, such as salmon, appeared in the Caspian Sea.
Therefore, geographers consider the Caspian Sea to be a huge salt lake, while biologists rightfully call it a sea. The Caspian Sea is a unique natural formation, a living heir to the Ancient World.
Oceans and seas of the Earth - Black Sea
The Black Sea is also very interesting. Despite almost the same area as the Caspian or Baltic Seas, its volume is much larger - 6 and 12.5 times, respectively! Great depth affects - with the exception of the shallow northern part, the seabed drops rather sharply, in a dozen or two kilometers from the coast you can already find depths over a kilometer.
The average depth of the Black Sea is 400 m, the largest is 2211 m. However, only 1/6 of the volume and a quarter of the bottom area of this sea are accessible to ordinary marine life.
The fact is that below 150-200 m in the Black Sea, the "death zone" begins. There: there are only some bacteria that do not need oxygen. This is due to the hydrogen sulfide gas dissolved in sea water and poisonous to ordinary marine inhabitants. In other seas, it is also sometimes found, but in much smaller quantities, most often in small depressions. But the Black Sea was not lucky: the water almost does not mix.
Salt water is heavier than fresh water, and large, powerful rivers flow into the Black Sea: Danube, Dnieper, Don ... Fresh river water so much arrives that it does not have time to evaporate. The Bosphorus Strait, through which the Black Sea basin is connected with all the oceans, is narrow and rather shallow, a powerful current runs along its surface - this is almost half desalinated (compared to the ocean) water flows into the Marmara and Mediterranean seas.
If it were not for the counter current along the bottom of the Bosphorus, arising from the different density of water in the neighboring seas, vacationers on the beaches of Sochi would bathe in fresh water, which may taste a little salty.
Such a stagnant system also has one more drawback, which is very significant for the life of the sea. The rivers carry a lot nutrients, but most of of them settles to the bottom. In other seas, the mixing of water and the movement of marine life gradually returns these substances to the upper, most convenient layers for life, but in the Black Sea everything remains at the bottom.
Oceans and seas of the Earth - Sea of Azov
Connecting with the Black Sea, the small Sea of Azov is in many ways reminiscent of its large neighbor. There is also little salt in its water, it is also connected to the rest of the ocean by a narrow strait - the Kerch Strait, even shallower than the Bosphorus.
True, live Sea of Azov much easier. First, it evaporates excess water in the salt lake Sivash, which is shallow and well warmed up in the summer months. Secondly, there is no such deep basin. In general, there are no great depths.
The Azov Sea is the smallest on the planet. Its average depth is only 8 m, 50 times less than that of the Black Sea, and the greatest depth is 15 m.Living conditions are much better, and some Black Sea fish, such as herring and anchovy, constantly come here to leave offspring and feed. For the winter, they return to the Black Sea - away from the ice.
However, the shallow depth also has its drawbacks: in the summer the sea begins to literally choke. Shallow water warms up quickly, and in warm water less oxygen dissolves. At the same time, algae and various microorganisms that absorb oxygen are also rapidly developing - the sea "blooms". Such "blooming" does not bring joy to anyone, it is a big disaster for fish and other inhabitants. They can only be saved by a storm, which will stir the water almost to the very bottom, cool it and fill it with oxygen.
That is, each sea has its own characteristics, problems, advantages and disadvantages.
How the sea differs from the ocean
This is what distinguishes each sea from the rest of the body of water. According to the definition of geographers, the sea is a part of the World Ocean, separated from it by land or underwater elevations, different from open ocean its climatic (weather), water (hydrological, as scientists say) and other features.
The more the sea is closed, fenced off from the rest of the ocean, the more features... Usually distinguish between inland seas (such as the Black, Azov, Mediterranean, surrounded on all sides by land), marginal (adjacent to land by one or two coasts, like most of the seas of the Arctic Ocean) and inter-island (separated from the ocean by chains of islands, for example, the Fiji Sea in the Pacific).
At the same time, attention is paid not to the size of the sea, but to its life, scientifically - to the regime. On the map, you can find quite significant bodies of water that did not deserve the name of the sea. These are the bays.
What is a bay on the sea or ocean
A bay is a part of a reservoir that juts deep into the land (a special international rule even determines how much), but freely communicates with its “parent” reservoir and retains all its features.
In turn, the bays are divided into different types: narrow and deep fjords with steep rocky shores, shallow lagoons and estuaries, bays sheltered from waves or winds, and many others. It also happens that almost half of the sea consists of various bays, for example, Baltic or White. There are also ocean bays: the Bay of Biscay of the Atlantic famous for its storms, the Bay of Bengal of the Indian Ocean. They are not inferior in size to many seas, as well as in depth.
Interesting about the oceans and seas of the Earth
Thus, the area of the Hudson Bay, deeply cut into the Canadian shores, is larger than that of the Black, Azov and Caspian Seas combined, and the depth is solid - up to 258 m. But it is not called the sea. The Gulf of Mexico is almost twice the size of the Hudson's, its area is 1555 thousand km, maximum depth- 3822 m. But it is not considered the sea either. Bay, and that's it!
And the Sea of Marmara with an area of 11.5 thousand km, which barely managed to squeeze between the Black and Mediterranean seas, is called by everyone only the sea. With the Mediterranean, in general, it turns out to be a real confusion; it is divided into several more seas: the Aegean, Adriatic, Ionian, Tyrrhenian ... And the Ligurian Sea is not even on every map: it looks more like a small bay located between the shores of Italy and France, north of the island of Corsica.
This is the story about Earth's oceans and seas we will pause, the continuation will be! Whole abstract turned out!
The Mediterranean Sea connects to the Atlantic Ocean in the west through the Strait of Gibraltar. This closed sea is surrounded by land on all sides. The ancient Greeks called the Mediterranean Sea - the sea in the middle of the Earth. At that time, this name was fully justified, because all the ancient European and North African civilizations appeared in the basin of this sea. And it was the Mediterranean Sea that served as the main route for contacts between them.
Interesting fact: the Mediterranean is said to be the remnants of its former greatness. Previously, in its place was the ancient Tethys Ocean. It stretched far to the east and was much wider. Today, from the Tethys, besides the Mediterranean Sea, only the drying up Aral Sea and Caspian Sea, as well as, Black, Azov and Sea of Marmara... The last three seas include the Mediterranean Sea basin.
In addition, inside the Mediterranean Sea, the following are distinguished as separate seas: Alboran, Balearic, Ligurian, Tyrrhenian, Adriatic, Ionian, Aegean, Cretan, Libyan, Cyprus and Levantine seas.
Detailed physical map of the Mediterranean seas in Russian. To enlarge, just click on the picture.
The currents of the Mediterranean Sea are not quite ordinary. Under the influence of high temperatures, a lot of water evaporates and, therefore, the consumption of fresh water prevails over its arrival. This naturally leads to a decrease in the water level and it has to be drawn from the Atlantic Ocean and the Black Sea. Interestingly, at a depth in saltier layers, the opposite process takes place and salty water flows into the Atlantic Ocean.
In addition to the above factors, the currents of the Mediterranean Sea are mainly caused by wind processes. Their speed in the open parts of the sea is 0.5-1.0 km / h, in the straits it can increase to 2-4 km / h. (for comparison, the Gulf Stream moves to the North at a speed of 6-10 km / h.).
The magnitude of tides is usually less than one meter, but there are places where, together with wind surges, it can reach up to four meters (for example, the northern coast of the island of Corsica or the Strait of Genoa). In narrow straits (Strait of Messina), tides can cause strong currents. In winter, the waves reach their maximum level and the wave height can reach 6-8 m.
The water of the Mediterranean Sea has an intense blue color and a relative transparency of 50-60 m. It is one of the saltiest and warmest seas in the world. In summer, the water temperature varies from 19 to 25 degrees, while in the east it can reach 27-3 ° C. In winter, the average water temperature decreases from north to south and varies between 8-17 ° C in the east and in the central part of the sea. Moreover, in the west temperature regime more stable and the temperature is kept between 11-15 ° C.
There are many large and small islands in the Mediterranean Sea, and almost every one of them is an attraction for many tourists. Let's name just a few of them:
The islands of Majorca and Ibiza in Spain, Sardinia and Sicily in Italy, Corfu, Crete and Rhodes in Greece, Corsica in France, as well as Cyprus and Malta.
How many oceans are there on Earth? I think even fifth graders will immediately answer: four - and will list: Atlantic, Indian, Pacific and Arctic. Everything?
But it turns out that four oceans are already outdated information. Today, scientists add to them a fifth - the Southern, or Antarctic Ocean.
Browse the wonderful and good article:
However, the number of oceans and especially their boundaries are still the subject of controversy. In 1845, the Geographical Society of London decided to count five oceans on Earth: Atlantic, Arctic, Indian, Quiet, Northern and Yuzhny, or Antarctic. This division was also confirmed by the International Hydrographic Bureau. But even later for a long time some scientists continued to believe that there are only four "real" oceans on Earth: Atlantic, Pacific, Indian and North, or Arctic Ocean... (In 1935 Soviet government approved the traditional Russian name - .)
So how many oceans are there actually on our planet? The answer may be unexpected: there is a single World Ocean on Earth, which people for their convenience (primarily navigation) have divided into parts. Who will confidently undertake to draw the border where the waves of one ocean end and the waves of the other begin? ..
We have figured out what the oceans are. And what do we call the seas and how many are on Earth? After all, the first acquaintances with water element started off the coast of the seas.
Experts call the seas "parts of the oceans that are separated from the open ocean by mountains or simply land." At the same time, sea regions, as a rule, differ from oceans and meteorological conditions, that is, weather, and even climate. Oceanologists distinguish between internal, land-locked, seas and external seas, as parts of the open ocean. There are seas and no shores at all, just sections of the ocean. For example the waters between the islands.
How many seas are there on Earth? Ancient geographers believed that there are only seven of them in the world, seven seas-oceans. Today, the International Hydrographic Bureau has 54 seas on Earth. But this figure is not very accurate, because some seas not only do not have shores, but are also located inside other water basins, and their names remained either due to historical habit or for the convenience of navigation.
Ancient civilizations developed along the banks of rivers, and rivers (I mean large streams of water) flow into the seas and oceans. So from the very beginning, people had to get acquainted with the water element. Moreover, each great civilization the past had its own sea. The Chinese have their own (later it turned out that this is a part). The ancient Egyptians, Greeks, Romans have their own - the Mediterranean Sea. Indians, Arabs - the shores of the Indian Ocean, the waters of which each people called in their own way. There were other centers of civilizations and other major seas in the world.
In ancient times, people did not know very much about the world around them and therefore they attributed special mystical meanings to many unknowns. So even in those days, when even great thinkers did not know and did not exist geographical maps of the world, they believed that there are seven seas on Earth. The number seven, according to the ancestors, was sacred. The ancient Egyptians have 7 planets in the sky. 7 days of the week, 7 years - a cycle of calendar years. Among the Greeks, the number 7 was dedicated to Apollo: on the seventh day before the new moon, a sacrifice was brought to him.
According to the Bible, the world was created by God in 7 days. Pharaoh dreamed of 7 fat and 7 skinny cows. Seven is found as the number of evil (7 devils). In the Middle Ages, many peoples of the nobility have a tale of seven wise men.
V Ancient world the seven wonders of the world were considered: Pyramids of Egypt, the hanging gardens of the Babylonian queen Semiramis, the lighthouse in Athexandria (III century BC), the Colossus of Rhodes, the statue of Olympian Zeus created by the great sculptor Phidias, the Ephesian temple of the goddess Artemis and the mausoleum at Gapikarnas.
How could one do without the sacred number in geography: there were seven hills, seven lakes, seven islands and seven seas?
We will not list everything. As a European resident (and I live in the city of St. Petersburg), I will only tell you about the main historical sea of European civilization -.
Today there are 81 seas.
All seas are divided according to their location in the following directions: Atlantic, Pacific, inland seas and seas, with Southern Ocean, North and Indian Ocean.
Views of the seas
Traditionally, the seas are usually divided into four groups:
- inter-island,
- semi-closed,
- outlying,
- internal.
Inland seas are found "inside" continents, but can be connected to the ocean or other adjacent sea. Such seas are subject to great influence of the land, the water in them may have a variable level. These seas include: the Dead Sea, the Aral Sea and the Caspian Sea.
Some scientists and researchers consider the coastal sea, and therefore the inland seas, the inter-island seas, they do not belong to the general list.
Marginal seas are located on the edge of the land and have direct access to the ocean, but the semi-enclosed seas are fenced off by the mainland, but partially.
The inter-island seas, based on the basis of their name, are located between the various islets. The inter-island seas include the following: Fiji, Java and New Guinea Sea.
Lack of seas
Compared to land and land in general, the area of the seas on the planet is small. There is even a garbage sea that is due to a large number waste turns into a floating dump, polluting. Such seas of plastic and other waste have been observed in the waters of the Indian and Pacific Oceans.
The endangered seas are also worth mentioning. For example, the huge Aral Sea due to the influence economic activity man began to disappear, the water seemed to evaporate. And all this happened due to water intake from other rivers, therefore fresh water ceased to flow into the Aral Sea. As a result, all the fauna that lived in this once huge sea simply disappeared, the climate of the area changed: where the gardens previously bloomed and the breeze was blowing, today there are only desert dunes and the skeletons of ships that have rotted from time to time. This terrible tragedy of the region, which has not gone unnoticed in the world. Attempts were made to sea artificially, but they were in vain. More than half a century later, it became obvious that only natural forces able to restore the original balance of water and land, today the sea is slowly reviving.
The issue of the ecological situation and the issue of safety water resources every year it becomes more acute: scientists assume that climate change and the active expansion of man into the natural elements will erase more than one sea from the face of the planet, and a war between peoples is not far off, not for territory, but for fresh and salt water.
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