Nearly 95% of all water on Earth is salty and unusable. It consists of seas, oceans and salt lakes. Together, all this is called the oceans. Its area is three quarters of the entire area of the planet.
Oceans - what is it?
The names of the oceans are familiar to us since elementary school. This is the Pacific, otherwise called the Great, Atlantic, Indian and Northern Arctic. Together they are called the oceans. Its area is more than 350 million km 2 . This is a huge territory, even on a planetary scale.
The continents divide the World Ocean into four oceans known to us. Each of them has its own characteristics, its own unique underwater world, changing depending on the climatic zone, temperature of the currents and bottom topography. The map of the oceans shows that they are all interconnected. None of them are surrounded by land on all sides.
Ocean Science - Oceanology
How do we know that seas and oceans exist? Geography is a school subject that first introduces us to these concepts. But more special study of the oceans involved in a special science - oceanology. She considers water open spaces as an integral natural object, studies the biological processes occurring inside it, and its connection with other constituent elements of the biosphere.
With this science, the ocean depths are studied in order to achieve such goals:
- increasing efficiency and ensuring the safety of underwater and surface navigation;
- optimization of the use of mineral resources of the ocean floor;
- maintaining the biological balance of the ocean environment;
- improvement of meteorological forecasts.
How did the modern names of the oceans come about?
The name of each geographical object is given for a reason. Any name has certain historical prerequisites or is associated with the characteristic features of a particular territory. Let's find out when and how the names of the oceans came about and who came up with them.
- Atlantic Ocean. The works of the ancient Greek historian and geographer Strabo described this ocean, calling it Western. Later, some scholars called it the Hesperides Sea. This is confirmed by a document dated 90 BC. Already in the ninth century AD, the name “Sea of Darkness,” or “Sea of Darkness” was voiced by Arab geographers. The Atlantic Ocean received such a strange name because of the clouds of sand and dust that lifted winds above it, constantly blowing from the African continent. For the first time, the modern name sounded in 1507, after Columbus reached the shores of America. Officially, this name was fixed in geography in 1650 in the scientific works of Bernhard Waren.
- The Pacific Ocean was named so by the Spanish navigator Fernand Magellan. Despite the fact that it is quite stormy and often there are storms and tornadoes, during the expedition of Magellan, which lasted a year, the weather was constantly good, calm was observed, and this was the reason to think that the ocean was really calm and calm. When the truth was revealed, nobody began to rename the Pacific Ocean. In 1756, the famous traveler and explorer Bayush proposed to call him Great, since it is the largest ocean of all. Until today, both of these names are used.
- The reason for giving the name to the Arctic Ocean was a lot of ice floes drifting in its waters, and, of course, geographical location. His second name - the Arctic - came from the Greek word "arktikos", which means "northern".
- With the name of the Indian Ocean, everything is extremely simple. India is one of the first countries known to the Ancient World. The waters that wash its shores were named after her.
Four oceans
How many oceans are there on the planet? This question seems to be the simplest, but for many years it has been causing discussion and debate among oceanologists. The standard list of oceans looks like this:
1. Quiet.
2. Indian.
3. The Atlantic.
4. The Arctic.
But from ancient times there is another opinion according to which the fifth ocean stands out - the Antarctic, or Southern. Arguing this decision, oceanologists cite the fact that the waters washing the coast of Antarctica are very peculiar and the system of currents in this ocean is different from the rest of the water. Not everyone agrees with this decision, so the problem of separation of the oceans remains relevant.
The characteristics of the oceans are different depending on many factors, although it may seem that they are all the same. Let's get to know each of them and find out the most important information about everyone.
Pacific Ocean
It is also called Great, because it has the largest area of all. The Pacific basin occupies a little less than half the area of all the world's water expanses and equals 179.7 million km².
The structure includes 30 seas: Japan, Tasmanovo, Yavan, South China, Okhotsk, Filipino, Novogvineysk, Sea of Sava, Sea of Halmacher, Sea of Koro, Sea of Mindanao, Yellow, Sea of Visayan, Sea of Aki, Solomonovo, Sea of Bali, Sea of Samair, Coral, Banda, Sulu, Sulawesi, Fiji, Moluks, Komotes, Sea of Seram, Sea of Flores, Sea of Sibuyan, East China, Bering, Sea of Amudesen. All of them occupy 18% of the total area of the Pacific Ocean.
By the number of islands, he is also a leader. They number about 10 thousand. The largest islands of the Pacific Ocean are New Guinea and Kalimantan.
The seabed contains more than a third of the world's reserves of natural gas and oil, which are actively mined in the offshore areas of China, the United States of America and Australia.
In the Pacific, there are many transport routes connecting Asian countries with South and North America.
Atlantic Ocean
It is the second largest in the world, and this is clearly demonstrated by the map of the oceans. Its area is 93 360 thousand km 2 . The Atlantic Ocean basin contains 13 seas. All have a coastline.
An interesting fact is that in the middle of the Atlantic Ocean there is the fourteenth sea - Sargasovo, called the sea without coasts. Its boundaries are ocean currents. It is considered the largest sea area in the world.
Another feature of this ocean is the maximum influx of fresh water, which is provided by large rivers of North and South America, Africa and Europe.
By the number of islands, this ocean is the exact opposite of the Pacific. There are very few of them. But on the other hand, it is in the Atlantic Ocean that the largest island of the planet is located - Greenland - and the most remote island - Bouvet. Although sometimes Greenland is reckoned among the islands of the Arctic Ocean.
Indian Ocean
Interesting facts about the third largest ocean will make us even more surprised. The Indian Ocean was the first known and explored. He is the keeper of the largest complex of coral reefs.
The waters of this ocean keep the secret of a mysterious phenomenon, still not explored properly. The fact is that luminous circles of regular shape periodically appear on the surface. According to one version, this is a glow of plankton rising from the depths, but their ideal spherical shape is still a mystery.
Near the island of Madagascar, you can observe a unique natural phenomenon - an underwater waterfall.
Now a few facts about the Indian Ocean. Its area is 79 917 thousand km 2 . The average depth is 3,711 m. It washed by 4 continents and composed of 7 seas. Vasco da Gama is the first explorer to cross the Indian Ocean.
Interesting facts and characteristics of the Arctic Ocean
It is the smallest and coldest of all oceans. Area - 13 100 thousand km 2 . It is also the most shallow, the average depth of the Arctic Ocean is only 1225 m. It consists of 10 seas. By the number of islands, this ocean is second only to the Pacific.
The central part of the ocean is covered in ice. In the southern regions, ice floes and icebergs are observed. Sometimes you can meet the whole ice floating islands 30-35 m thick. It is here that the notorious Titanic crashed, colliding with one of them.
Despite the harsh climate, the Arctic Ocean is the habitat of many animal species: walruses, seals, whales, gulls, jellyfish and plankton.
Depth of the oceans
We already know the names of the oceans and their features. But what is the deepest ocean? Let's figure it out.
A contour map of the oceans and ocean floor shows that the bottom topography is as diverse as the topography of the continents. Under the thickness of sea water are hidden indentations, depressions and elevations like mountains.
The average depth of all four oceans combined is 3700 m. The Pacific Ocean is considered the deepest, the average depth of which is 3980 m, followed by the Atlantic - 3600 m, followed by the Indian - 3710 m. The last on this list, as already mentioned, is the Arctic Ocean, the average depth of which is only 1225 m.
Salt is the main feature of ocean waters
Everyone knows how the water of the seas and oceans differs from fresh river water. Now we will be interested in such a characteristic of the oceans as the amount of salt. If you think that the water is equally salty everywhere, you are very mistaken. The salt concentration in ocean waters can vary significantly even within a few kilometers.
The average salinity of ocean waters is 35 ‰. If we consider this indicator separately for each ocean, then Arctic Arctic is the least salty of all: 32 ‰. The Pacific Ocean - 34.5 ‰. The salt content in the water here is reduced due to the large amount of precipitation, especially in the equatorial zone. Indian Ocean - 34.8 ‰. Atlantic - 35.4 ‰. It is important to note that bottom waters have a lower salt concentration than surface waters.
The most saline seas of the oceans are the Red (41 ‰), the Mediterranean Sea and the Persian Gulf (up to 39 ‰).
World Ocean Records
- The deepest place in the oceans is the Mariinsky Depression, its depth is 11,035 m above the surface water level.
- If we consider the depth of the seas, then the deepest sea is considered to be the Philippine. Its depth reaches 10 540 m. The Coral Sea with the maximum depth of 9140 m is second in this indicator.
- The largest ocean is the Pacific. Its area is greater than the area of all terrestrial land.
- The salty sea is the Red Sea. It is located in the Indian Ocean. Salt water well supports all objects falling into it, and to drown in this sea, you need to try very hard.
- The most mysterious place is in the Atlantic Ocean, and its name is the Bermuda Triangle. Many legends and mysteries are associated with it.
- The most poisonous sea creature is the blue-ringed octopus. It lives in the Indian Ocean.
- The largest coral cluster in the world is the Great Barrier Reef, located in the Pacific Ocean.