Almost 95% of all water on Earth is s alty and unusable. It consists of seas, oceans and s alt lakes. Collectively, all this is called the World Ocean. Its area is three-quarters of the entire area of the planet.
World Ocean - what is it?
Ocean names have been familiar to us since elementary school. This is the Pacific, otherwise called the Great, Atlantic, Indian and Arctic. All of them together are called the World Ocean. Its area is more than 350 million km2. This is the largest territory even on the scale of the planet.
The continents divide the World Ocean into four oceans known to us. Each of them has its own characteristics, its own unique underwater world, which changes depending on the climatic zone, the temperature of the currents and the bottom topography. The map of the oceans shows that they are all interconnected. None of them are surrounded by land on all sides.
The science that studies the oceans is oceanology
How do we know that there are seas and oceans? Geography is a school subject that first introduces us to theseconcepts. But a special science, oceanology, is engaged in a deeper study of the oceans. She considers the expanses of water as an integral natural object, studies the biological processes occurring inside it, and its relationship with other constituent elements of the biosphere.
This science studies the ocean depths to achieve the following goals:
- improving the efficiency and safety of underwater and surface navigation;
- optimizing the use of ocean floor minerals;
- maintaining the biological balance of the oceanic environment;
- Improve 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 background or is associated with the characteristic features of a particular territory. Let's find out when and how the names of the oceans originated and who came up with them.
- The Atlantic Ocean. The works of the ancient Greek historian and geographer Strabo described this ocean, calling it Western. Later, some scientists called it the Hesperid Sea. This is confirmed by a document dated 90 BC. Already in the ninth century AD, Arab geographers voiced the name "Sea of Darkness", or "Sea of Darkness". The Atlantic Ocean received such a strange name because of the clouds of sand and dust that the winds constantly blowing from the African continent raised above it. For the first time the modern name sounded in 1507, afterhow 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 Ferdinand Magellan. Despite the fact that it is quite stormy and there are often storms and tornadoes, during the expedition of Magellan, which lasted a year, there was always good weather, calm was observed, and this was a reason to think that the ocean was really quiet and calm. When the truth was revealed, no one began to rename the Pacific Ocean. In 1756, the famous traveler and explorer Bayush suggested calling it the Great, as 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 the many ice floes drifting in its waters, and, of course, the geographical location. His second name - Arctic - comes 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 banks 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 caused discussions and disputes among oceanologists. The standard list of oceans looks like this:
1. Quiet.
2. Indian.
3. Atlantic.
4. Arctic.
But since ancient times there has been another opinion, according to which the fifth ocean stands out - the Antarctic, or the South. Arguing for such a decision, oceanologists cite as evidence the fact that the waters washing the shores of Antarctica are very peculiar and the system of currents in this ocean differs from the rest of the water expanses. Not everyone agrees with this decision, so the problem of dividing the World Ocean 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 acquainted with each of them and find out the most important information about all of them.
Pacific Ocean
It is also called the Great, because it has the largest area among all. The Pacific Ocean basin occupies a little less than half the area of all the world's water spaces and is equal to 179.7 million km².
The composition includes 30 seas: Japan, Tasman, Java, South China, Okhotsk, Philippine, New Guinea, Savu Sea, Halmahera Sea, Koro Sea, Mindanao Sea, Yellow, Visayan Sea, Aki Sea, Solomon Sea, Sea Bali, Samair Sea, Coral Sea, Banda, Sulu, Sulawesi, Fiji, Moluckoe, Komotes, Seram Sea, Flores Sea, Sibuyan Sea, East China Sea, Bering Sea, Amudesena Sea. All of them occupy 18% of the total area of the Pacific Ocean.
It is also the leader in the number of islands. There are about 10 thousand of them. The largest Pacific islands are New Guinea and Kalimantan.
The seabed contains more than a third of the world's natural gas and oil reserves, which are actively produced mainly in offshore zones in China, the United States of America and Australia.
There are many transport routes across the Pacific Ocean connecting the countries of Asia with South and North America.
Atlantic Ocean
Is the second largest in the world, and this is clearly demonstrated by the map of the oceans. Its area is 93,360 thousand km2. The Atlantic Ocean basin contains 13 seas. They 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 shores. Its boundaries are ocean currents. It is considered the largest sea in the world by area.
Another feature of this ocean is the maximum inflow of fresh water, which is provided by the large rivers of North and South America, Africa and Europe.
In terms of the number of islands, this ocean is the exact opposite of the Pacific. There are very few of them here. But on the other hand, it is in the Atlantic Ocean that the largest island of the planet - Greenland - and the most remote island - Bouvet - are located. Although sometimes Greenland is classified as an island in 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. It is the custodian of the largest coral reef complex.
The waters of this ocean hold the secret of a mysterious phenomenon that has not yet been properly investigated. The fact is that periodically appear on the surfaceluminous circles of the correct form. According to one version, this is the glow of plankton rising from the depths, but their ideal spherical shape is still a mystery.
Not far from the island of Madagascar, you can observe a one-of-a-kind natural phenomenon - an underwater waterfall.
Now some facts about the Indian Ocean. Its area is 79,917 thousand km2. The average depth is 3711 m. It washes 4 continents and has 7 seas. Vasco da Gama is the first explorer to swim across the Indian Ocean.
Interesting facts and characteristics of the Arctic Ocean
This is the smallest and coldest of all oceans. The area is 13,100 thousand km2. It is also the shallowest, the average depth of the Arctic Ocean is only 1225 m. It consists of 10 seas. By the number of islands, this ocean ranks second after the Pacific.
The central part of the ocean is covered with ice. In the southern regions, floating ice floes and icebergs are observed. Sometimes you can find whole ice floating islands 30-35 m thick. It was here that the infamous Titanic crashed, colliding with one of them.
Despite the harsh climate, the Arctic Ocean is home to many animal species: walruses, seals, whales, gulls, jellyfish and plankton.
Deep oceans
We already know the names of the oceans and their features. But what is the deepest ocean? Let's look into this matter.
Contour map of the oceans andocean floor shows that the bottom relief is as diverse as the relief of the continents. Under the thickness of the sea water, depressions, depressions and elevations like mountains are hidden.
The average depth of all four oceans combined is 3700 m. The deepest is the Pacific Ocean, the average depth of which is 3980 m, followed by the Atlantic - 3600 m, followed by the Indian - 3710 m. The last in this list, as already mentioned, is the Arctic Ocean, the average depth of which is only 1225 m.
S alt 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 s alt. If it seems to you that the water is equally s alty everywhere, you are very much mistaken. S alt concentrations in ocean waters can vary widely, even within a few kilometers.
The average salinity of ocean waters is 35 ‰. If we consider this indicator separately for each ocean, then the Arctic Ocean is the least s alty of all: 32 ‰. Pacific Ocean - 34.5 ‰. The s alt content in the water is low here 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 s alt concentration than surface waters.
The s altiest seas of the World Ocean are the Red Sea (41 ‰), the Mediterranean Sea and the Persian Gulf (up to 39 ‰).
World recordsocean
- The deepest place in the World Ocean is the Mariinsky Trench, its depth is 11,035 m from the surface water level.
- If we consider the depth of the seas, then the Philippine sea is considered the deepest. Its depth reaches 10,540 m. The second place in this indicator is the Coral Sea with a maximum depth of 9140 m.
- The largest ocean is the Pacific. Its area is larger than the area of the entire earth's land.
- The most s alty sea is Red. It is located in the Indian Ocean. S alt water is good at supporting all objects that fall into it, and it takes a lot of effort to drown in this sea.
- 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 accumulation of corals in the world - the Great Barrier Reef, located in the Pacific Ocean.
