The Indian Ocean is an integral part of the world's oceans. Its maximum depth is 7729 m (Zonda Trench), and the average depth is just over 3700 m, which is the second result after the depths of the Pacific Ocean. The size of the Indian Ocean is 76.174 million km2. This is 20% of the world's oceans. The volume of water is about 290 million km3 (together with all the seas).

The waters of the Indian Ocean are distinguished by their light blue color and good transparency. This is due to the fact that very few freshwater rivers flow into it, which are the main "troublemakers". By the way, due to this, the water in the Indian Ocean is much saltier compared to the salinity of other oceans.

Location of the Indian Ocean

Most of the Indian Ocean is in the Southern Hemisphere. It borders Asia to the north, Antarctica to the south, Australia to the east, and the African continent to the west. In addition, in the southeast, its waters connect with the waters of the Pacific Ocean, and in the southwest with the Atlantic Ocean.

Seas and gulfs of the Indian Ocean

The Indian Ocean does not have as many seas as other oceans. For example, in comparison with the Atlantic Ocean, they are 3 times less. Most of the seas are located in its northern part. In the tropical zone are: Red (the most salty sea on Earth), Laccadive, Arabian, Arafura, Timor and Andaman seas. The Antarctic zone hosts the d'Urville, Commonwealth, Davis, Riiser-Larsen, Cosmonauts seas.

The largest bays of the Indian Ocean are the Persian, Bengal, Oman, Aden, Prydz and the Great Australian.

Indian Ocean islands

The Indian Ocean is not distinguished by an abundance of islands. The largest islands of continental origin are Madagascar, Sumatra, Sri Lanka, Java, Tasmania, Timor. Also, there are volcanic islands, such as Mauritius, Renyon, Kerguelen, and coral - Chagos, Maldives, Andaman, etc.

Underwater world of the Indian Ocean

Since more than half of the Indian Ocean is located in the tropical and subtropical zones, its underwater world is very rich and diverse in terms of species. The coastal zone in the tropics is replete with numerous colonies of crabs and unique fish - mudskippers. Corals live in shallow waters, and various algae grow in temperate waters - calcareous, brown, red.

The Indian Ocean is home to dozens of species of crustaceans, molluscs and jellyfish. A fairly large number of sea snakes also live in the ocean waters, among which there are also poisonous species.

Sharks are a special pride of the Indian Ocean. Its waters are plowed by many species of these predators, namely tiger, mako, gray, blue, great white sharks, etc.

Mammals are represented by killer whales and dolphins. Several species of pinnipeds (seals, dugongs, seals) and whales live in the southern part of the ocean.

Despite all the richness of the underwater world, seafood fishing in the Indian Ocean is rather poorly developed - only 5% of the world's catch. Sardines, tuna, shrimp, lobsters, rays and lobsters are harvested in the ocean.

1. The ancient name of the Indian Ocean is Eastern.

2. In the Indian Ocean, ships are regularly found in good condition, but without a crew. Where he disappears is a mystery. Over the past 100 years, there have been 3 such ships - Tarbon, Houston Market (tankers) and the Cabin Cruiser.

3. Many species of the underwater world of the Indian Ocean have a unique property - they can glow. This is what explains the appearance of luminous circles in the ocean.

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Its area is 76 million km2. This ocean is widest in the Southern Hemisphere, and in the Northern Hemisphere it looks like a large sea, deeply cutting into the land. It was the large sea that the Indian Ocean was presented to people from ancient times up to.

The shores of the Indian Ocean are one of the areas of ancient civilizations. Scientists believe that navigation in it began earlier than in other oceans, about 6 thousand years ago. The Arabs were the first to describe ocean routes. The accumulation of information about the Indian Ocean began from the time of the voyage (1497-1499). At the end of the 18th century, the first measurements of its depths were made by an English navigator. A comprehensive study of the ocean began at the end of the 19th century. The largest studies were carried out by the British expedition on board the Challenger. Nowadays, dozens of expeditions from different countries are studying the nature of the ocean, revealing its riches.

The average depth of the ocean is about 3700 meters, and the maximum reaches 7729 meters in the Yavan Trench. An underwater ridge stretches in the western part of the ocean, connecting to the south with the Mid-Atlantic Ridge. Deep faults, areas and at the bottom of the ocean are confined to the center of the ridge in the Indian Ocean. These faults continue into and out on land. The ocean floor is crossed by numerous uplifts.

Location: The Indian Ocean is bounded from the north by Eurasia, from the west by the east coast of Africa, from the east by the western coast of Oceania and from the south by the waters of the South Sea, the border of the Atlantic and Indian oceans runs along the 20th meridian of east. D., between the Indian and Pacific Oceans - along the 147th meridian of E. d.

Square: 74.7 million km2

Average depth: 3 967 m.

Maximum depth: 7729 m (Zonda, or Yavansky, trench).

: from 30‰ to 37‰.

Additional Information: in the Indian Ocean there are islands, Sri Lanka, Socotra, Laccadive, Maldives, Andaman and Nicobar, Comoros, and some others.

The Indian Ocean has the fewest seas compared to other oceans. The largest seas are located in the northern part: the Mediterranean - the Red Sea and the Persian Gulf, the semi-enclosed Andaman Sea and the marginal Arabian Sea; in the eastern part - the Arafura and Timor seas.

There are relatively few islands. The largest of them are of continental origin and are located near the coast: Madagascar, Sri Lanka, Socotra. In the open part of the ocean, there are volcanic islands - Mascarene, Crozet, Prince Edward, etc. In tropical latitudes, coral islands rise on volcanic cones - Maldives, Laccadive, Chagos, Cocos, most of the Andaman, etc.

Shores in the N.-W. and the East are indigenous, in the S.-V. and the West are dominated by alluvial. The coastline is slightly indented, with the exception of the northern part of the Indian Ocean. Almost all the seas and large bays (Aden, Oman, Bengal) are located here. In the southern part there are the Gulf of Carpentaria, the Great Australian Gulf and the gulfs of Spencer, St. Vincent, etc.

A narrow (up to 100 km) continental shelf (shelf) stretches along the coast, the outer edge of which has a depth of 50-200 m (only near Antarctica and northwestern Australia up to 300-500 m). The continental slope is a steep (up to 10-30°) ledge, locally dissected by the underwater valleys of the Indus, Ganges, and other rivers. m). The bed of the Indian Ocean is divided by ridges, mountains and ramparts into a number of basins, the most significant of which are the Arabian Basin, the West Australian Basin, and the African-Antarctic Basin. The bottom of these basins is formed by accumulative and hilly plains; the first are located near the continents in areas with an abundant supply of sedimentary material, the second - in the central part of the ocean. Among the numerous ridges of the bed, the straightness and length (about 5,000 km) distinguish the meridional East Indian Ridge, which connects in the south with the latitudinal West Australian Ridge; large meridional ridges stretch to the south from the Hindustan peninsula and about. Madagascar. Volcanoes are widely represented on the ocean floor (Mt. Bardina, Mt. Shcherbakov, Mt. Lena, and others), which in places form large massifs (to the north of Madagascar) and chains (to the east of the Cocos Islands). The mid-ocean ridges are a mountain system consisting of three branches that radiate from the central part of the ocean to the north (Arabian-Indian ridge), southwest. (West Indian and African-Antarctic ridges) and Yu.-V. (Central Indian Ridge and Australo-Antarctic Rise). This system has a width of 400–800 km, a height of 2–3 km, and is most dissected by an axial (rift) zone with deep valleys and rift mountains bordering them; transverse faults are characteristic, along which horizontal displacements of the bottom up to 400 km are noted. The Australo-Antarctic Rise, in contrast to the median ridges, is a gentler swell 1 km high and up to 1500 km wide.

The bottom sediments of the Indian Ocean are thickest (up to 3-4 km) at the foot of the continental slopes; in the middle of the ocean - small (about 100 m) thickness and in places where the dissected relief is distributed - discontinuous distribution. The most widely represented are foraminiferal (on the continental slopes, ridges and at the bottom of most basins at a depth of up to 4700 m), diatoms (south of 50 ° S), radiolarian (near the equator) and coral sediments. Polygenic sediments - red deep-sea clays - are distributed south of the equator at a depth of 4.5-6 km or more. Terrigenous sediments - off the coast of the continents. Chemogenic sediments are mainly represented by iron-manganese nodules, while riftogenic sediments are represented by destruction products of deep rocks. Outcrops of bedrocks are most often found on continental slopes (sedimentary and metamorphic rocks), mountains (basalts) and mid-ocean ridges, where, in addition to basalts, serpentinites and peridotites have been found, representing little-altered matter of the Earth's upper mantle.

The Indian Ocean is characterized by the predominance of stable tectonic structures both on the bed (thalassocratons) and along the periphery (continental platforms); active developing structures - modern geosynclines (Sonda arc) and georiftogenals (mid-ocean ridge) - occupy smaller areas and continue in the corresponding structures of Indochina and rifts of East Africa. These main macrostructures, which differ sharply in morphology, the structure of the earth's crust, seismic activity, and volcanism, are subdivided into smaller structures: plates, usually corresponding to the bottom of oceanic basins, blocky ridges, volcanic ridges, sometimes topped with coral islands and banks (Chagos, Maldives, etc.). .), trench-faults (Chagos, Ob, etc.), often confined to the foot of blocky ridges (East Indian, West Australian, Maldives, etc.), fault zones, tectonic ledges. Among the structures of the Indian Ocean bed, a special place (in terms of the presence of continental rocks - granites of the Seychelles and the continental type of the earth's crust) is occupied by the northern part of the Mascarene Range - a structure that is apparently part of the ancient Gondwana mainland.

Minerals: on the shelves - oil and gas (especially the Persian Gulf), monazite sands (the coastal region of Southwestern India), etc.; in rift zones - ores of chromium, iron, manganese, copper, etc.; on the bed - huge accumulations of iron-manganese nodules.

The climate of the northern part of the Indian Ocean is monsoonal; in summer, when an area of ​​low pressure develops over Asia, southwestern flows of equatorial air dominate here, in winter - northeastern flows of tropical air. South of 8-10 ° S sh. atmospheric circulation is much more constant; here, in tropical (summer and subtropical) latitudes, stable southeasterly trade winds dominate, and in temperate latitudes, extratropical cyclones moving from West to East. In tropical latitudes in the western part, hurricanes occur in summer and autumn. The average air temperature in the northern part of the ocean in summer is 25-27 °C, off the coast of Africa - up to 23 °C. In the southern part, it decreases in summer to 20-25 ° C at 30 ° S. sh., up to 5-6 ° С at 50 ° S. sh. and below 0 ° С south of 60 ° S. sh. In winter, the air temperature varies from 27.5 °C near the equator to 20 °C in the northern part, to 15 °C at 30 ° S. sh., up to 0-5 ° С at 50 ° S. sh. and below 0 ° С south of 55-60 ° S. sh. At the same time, in the southern subtropical latitudes, the temperature in the West all year round under the influence of the warm Madagascar current is 3-6 °C higher than in the East, where the cold West Australian current exists. Cloudiness in the monsoon northern part of the Indian Ocean in winter is 10-30%, in summer up to 60-70%. In summer, there is also the greatest amount of precipitation. The average annual precipitation in the east of the Arabian Sea and the Bay of Bengal is more than 3000 mm, near the equator 2000-3000 mm, in the west of the Arabian Sea up to 100 mm. In the southern part of the ocean, the average annual cloudiness is 40-50%, south of 40 ° S. sh. - up to 80%. The average annual precipitation in the subtropics is 500 mm to the east and 1,000 mm to the west; in temperate latitudes, more than 1,000 mm; near Antarctica, it drops to 250 mm.

The circulation of surface waters in the northern part of the Indian Ocean has a monsoonal character: in summer - northeast and east currents, in winter - southwest and west currents. During the winter months between 3° and 8° S. sh. an inter-trade (equatorial) countercurrent develops. In the southern part of the Indian Ocean, water circulation forms an anticyclonic circulation, which is formed from warm currents - the South Trade Winds in the north, Madagascar and Needles in the West, and cold currents - the Western Winds in the South and the West Australian in the East South of 55 ° S. sh. several weak cyclonic water cycles develop, closing off the coast of Antarctica with an easterly current.

The heat balance is dominated by a positive component: between 10° and 20° N. sh. 3.7-6.5 GJ/(m2×year); between 0° and 10°S sh. 1.0-1.8 GJ/(m2×year); between 30° and 40°S sh. - 0.67-0.38 GJ/(m2×year) [from - 16 to 9 kcal/(cm2×year)]; between 40° and 50°S sh. 2.34-3.3 GJ/(m2×year); south of 50°S sh. -1.0 to -3.6 GJ/(m2×yr) [-24 to -86 kcal/(cm2×yr)]. In the expenditure part of the heat balance north of 50 ° S. sh. the main role belongs to the cost of heat for evaporation, and south of 50 ° S. sh. - heat exchange between the ocean and the atmosphere.

The surface water temperature reaches its maximum (over 29 °C) in May in the northern part of the ocean. In the summer of the Northern Hemisphere, it is 27-28 ° C here and only off the coast of Africa decreases to 22-23 ° C under the influence of cold waters coming to the surface from the depths. At the equator, the temperature is 26-28 ° C and decreases to 16-20 ° C at 30 ° S. sh., up to 3-5 ° С at 50 ° S. sh. and below -1 ° С south of 55 ° S. sh. In the winter of the Northern Hemisphere, the temperature in the north is 23–25°C, at the equator 28°C, and at 30°S. sh. 21-25 ° С, at 50 ° S sh. from 5 to 9 ° С, south of 60 ° S sh. temperatures are negative. In subtropical latitudes all year round in the West, the water temperature is 3-5 °C higher than in the East.

The salinity of water depends on the water balance, which is formed on average for the surface of the Indian Ocean from evaporation (-1380 mm/year), precipitation (1000 mm/year) and continental runoff (70 cm/year). The main flow of fresh water comes from the rivers of South Asia (Ganges, Brahmaputra, etc.) and Africa (Zambezi, Limpopo). The highest salinity is observed in the Persian Gulf (37-39‰), in the Red Sea (41‰) and in the Arabian Sea (more than 36.5‰). In the Bay of Bengal and the Andaman Sea, it decreases to 32.0-33.0‰, in the southern tropics - to 34.0-34.5‰. In the southern subtropical latitudes, salinity exceeds 35.5‰ (maximum 36.5‰ in summer, 36.0‰ in winter), and south of 40°S. sh. drops to 33.0-34.3‰. The highest water density (1027) is observed in the Antarctic latitudes, the lowest (1018, 1022) - in the northeastern part of the ocean and in the Bay of Bengal. In the northwestern part of the Indian Ocean, the density of water is 1024-1024.5. The oxygen content in the surface water layer increases from 4.5 ml/l in the northern part of the Indian Ocean to 7-8 ml/l south of 50°S. sh. At depths of 200-400 m, the oxygen content is much lower in absolute value and varies from 0.21-0.76 in the north to 2-4 ml / l in the south, at greater depths it gradually increases again and in the bottom layer is 4.03 -4.68 ml/l. The color of the water is predominantly blue, in the Antarctic latitudes it is blue, in some places with greenish hues.

Tides in the Indian Ocean, as a rule, are small (near the coast of the open ocean and on the islands from 0.5 to 1.6 m), only at the tops of some bays they reach 5-7 m; in the Gulf of Cambay 11.9 m. The tides are predominantly semi-diurnal.

Ice forms at high latitudes and is carried by winds and currents along with icebergs in a northerly direction (up to 55°S in August and up to 65-68°S in February).

The deep circulation and vertical structure of the Indian Ocean is shaped by waters sinking into the subtropical (subsurface waters) and Antarctic (intermediate waters) convergence zones and along the continental slope of Antarctica (bottom waters), as well as from the Red Sea and the Atlantic Ocean (deep waters). Subsurface waters have a temperature of 10-18°C at a depth of 100-150 m to 400-500 m, a salinity of 35.0-35.7‰, intermediate waters occupy a depth of 400-500 m to 1000-1500 m, have a temperature of 4 to 10°C, salinity 34.2-34.6‰; deep waters at a depth of 1000-1500 m to 3500 m have a temperature of 1.6 to 2.8 ° C, salinity of 34.68-34.78‰; bottom waters below 3500 m in the south have a temperature of -0.07 to -0.24 ° C, salinity 34.67-34.69 ‰, in the north - about 0.5 ° C and 34.69-34.77 ‰ respectively.

Flora and fauna

The entire water area of ​​the Indian Ocean lies within the tropical and southern temperate zones. The shallow waters of the tropical zone are characterized by numerous 6- and 8-ray corals, hydrocorals, capable of creating islands and atolls together with calcareous red algae. The richest fauna of various invertebrates (sponges, worms, crabs, molluscs, sea urchins, brittle stars and starfish), small but brightly colored coral fish live among the powerful coral structures. Most of the coasts are occupied by mangroves, in which the mud jumper stands out - a fish that can exist in the air for a long time. The fauna and flora of the beaches and rocks that dry out at low tide are quantitatively depleted as a result of the depressing effect of the sun's rays. In the temperate zone, life on such stretches of coasts is much richer; dense thickets of red and brown algae (kelp, fucus, reaching the enormous size of macrocystis) develop here, various invertebrates are abundant. For the open spaces of the Indian Ocean, especially for the surface layer of the water column (up to 100 m), rich flora is also characteristic. Of the unicellular planktonic algae, several species of peredinium and diatom algae predominate, and in the Arabian Sea - blue-green algae, which often cause the so-called water bloom during mass development.

Copepods (more than 100 species) make up the bulk of the ocean's animals, followed by pteropods, jellyfish, siphonophores, and other invertebrates. Of the unicellular, radiolarians are characteristic; numerous squids. Of the fish, the most abundant are several species of flying fish, luminous anchovies - myctophids, dolphins, large and small tunas, sailfish and various sharks, poisonous sea snakes. Sea turtles and large marine mammals (dugongs, toothed and toothless whales, pinnipeds) are common. Among the birds, the most characteristic are albatrosses and frigates, as well as several species of penguins that inhabit the coasts of South Africa, Antarctica and islands lying in the temperate zone of the ocean.

Although the Indian Ocean is relatively small on the world map in terms of area, it has a rich, vibrant, unique flora and fauna.

This is the third largest body of water in the world, its depths keep many mysteries and secrets. Studied in nature studies classes in elementary school, then in high school, grades 5-7, this topic is often found in exam papers and tests.

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Characteristics of the Indian Ocean

The ocean washing the shores of Indochina is smaller in size than the Pacific and Atlantic oceans, and ranks third in size on Earth.

Its area is 76.17 million km², which is about 20% of the entire water surface.

The average depth of the ocean is about 3.7 thousand meters, while the maximum depth reaches 7.7 thousand meters in the east, in the area where the Yavan Trench is located.

The average temperature on the surface of the water can reach 20-27°C and reach up to 7°C at depth in the equatorial regions, the salinity is approximately 35%.

Research History

It is believed that it was this ocean that people began to overcome the very first, at the beginning ordinary wooden rafts were used for this.

Significant knowledge and information about the ocean has first appeared since the exploration of Vasco da Gama, carrying out his own plan to reach distant lands.

Geographical position

The salty waters of the ocean washes Asia from the north side, from the west they touch the coast of Africa, and the eastern currents rush to Australia, bordering on Antarctica in the south.

It also has intersections with the territories of the Atlantic and Pacific Oceans, one of which runs along the meridian of Cape Agulhas, and the other along Cape Horn. Located south of the Tropic of Cancer.

In the northern hemisphere, the Indian Ocean could easily be confused with the big sea, which was misleading for sailors and fishermen.

currents

For the most part, currents are directed in the opposite direction from the clockwise direction. In the north, they change with the onset of the season, which is associated with a change in winds. Currents located south of the equator are the same throughout the year.

In winter, the Northeast Monsoon, which originates in the Bay of Bengal, has a strong influence. It washes East Africa, splits, enters the Red Sea and gives rise to the Equatorial Countercurrent.

Seas

There are many seas in the Indian Ocean:

• Red sea;
• Mawson Sea;
• the Commonwealth Sea;
• Arabian Sea.

Indian Ocean on the physical map of the world (click to enlarge)

They are of great importance not only for tourism, but also important for the transportation and transport of goods. They have many unique natural features.

Climate and climatic zones

Due to the influence of the temperature regime of Asia, a monsoonal climate is established in the north, rich in cyclones moving towards the coasts.

In summer, heated sea waters begin to give moisture to the air, making it humid. It moves to the mainland and pours over the surface of the earth in the form of heavy rains. Thunderstorms, storms or cold typhoons are not uncommon in this area.

Flora and fauna

It is the colorful diversity of flora and fauna that makes the Indian Ocean so special.

At the bottom you can see all the variety of species of colorful sponges, starfish, corals, crustaceans.

All those delicacies that are served on the table live here: lobsters, shrimps, mussels, lobsters.

In these climatic zones, characteristic representatives of various fish species are found, not only suitable for catching and eating, but also distinguished by an unusual color, the beauty of which is difficult to compare with anything.

Islands and peninsulas

The largest and most famous island, of course, is Madagascar, with an area of ​​590,000 km2.

Madagascar island

Christmas Island originated from a volcano, the Maldives, Seychelles, Andaman Islands are also located there.

Sri Lanka

Tasmania, Sri Lanka, Zanzibar, Socotra are considered the largest separate islands. It is noteworthy that some of the islands used to be part of the mainland, and later separated and became islands.

Bottom relief

As the fauna in the Indian Ocean is diverse and unique, the structure of the oceanic bottom relief is also amazing.

A feature is the angle of the bottom in the Bay of Bengal, which is a unique phenomenon. The bottom is very diverse, in some parts reefs and characteristic faults predominate.

Deepest trench in the Indian Ocean

The deepest point in the ocean is the Yavan Trench, also called the Sunda Trench. The depth in it reaches about 7.7 thousand meters, at the bottom there is practically no relief.

In the area of ​​the Yavan trench not so long ago there was an earthquake of a huge scale, scientists fear that this will soon cause a shift in tectonic plates.

gulfs

In total there are 22 gulfs, the most significant of which can be called Persian (due to the huge oil reserves).

Persian Gulf

Many currents originate in the Bay of Bengal, affecting the temperature of water and air.

Features of nature

Strong winds and monsoons have a special effect on the currents and temperature of coastal areas.

It is also in these places that the richest variety of marine life, species of algae and corals is found.

Coastline

The coastline is heavily indented only from the north, where most of the major seas are located.

From the Persian Gulf, the ocean is protected by mountains from strong winds. In the rest of the territory it is almost flat.

Minerals

The Indian Ocean contains numerous and richest sources of oil and natural gas.

Near the coastlines, on the shelves, a variety of semi-precious stones and metals are mined, which are of significant importance for the world industry.

Environmental problems of the Indian Ocean

Problems with the environment appeared in connection with anthropogenic impacts that led to such a deplorable state of natural ecosystems.

Pollution of the waters of the Indian Ocean is influenced by many factors:

1. Starting with military operations and preparations for them, which are a serious source of the release of harmful and toxic substances. Warships heavily neglect environmental controls. At the bottom of the seas, a large number of sunken ships have accumulated since the time of ancient wars. The impact of metals also causes significant environmental damage.
2. Industrial and agricultural emissions dominate.
3. Pesticides, which are the most dangerous substances, cause irreparable damage to the environment.
4. The amount of garbage in the waters is growing rapidly, it gets there from the sides of ships or is thrown out by sewage from land. Plus, radioactive and toxic waste is buried at the bottom.

Types of economic activity

Fishing is not highly developed, as the animal world is insanely beautiful and serves more for the aesthetic enjoyment of tourists. In Antarctic waters, whaling used to be widespread, which was subsequently banned.

Tuna fishing is popular around the equator.

Off the coast of Australia, such valuable details of expensive jewelry as mother-of-pearl and natural pearls are mined.

As mentioned above, the Persian Gulf is one of the largest sources of oil production. The countries of the Indian Ocean in large quantities extract all the necessary mineral resources and raw materials here.

Attractions

Here are just some of the amazing places to look at:

As a conclusion, here are some interesting facts:

1. The volume of water in the ocean is the third largest in the world after the Pacific and Atlantic.
2. In ancient times, the ocean had the name "Eastern", later European discoverers and researchers renamed it.
3. The first swims were made before the advent of our era.
4. A significant contribution to the study of the sea region was made by Covilhã, Vasco da Gama and Cook.
5. In the bowels of the ocean there are almost 2 billion tons of black gold and 2.3 trillion tons of gas.
6. It happens that luminous circles appear on the surface of the ocean. It is believed that this is plankton in large quantities.
7. It is in the Indian Ocean that the sea with the highest salt content on Earth is located - the Red contains 42%.
8. The ocean contains a huge variety of coral reefs that have a great extent.

The Indian Ocean is the third largest ocean on Earth, covering about 20% of its water surface. Its area is 76.17 million km², volume - 282.65 million km³. The deepest point of the ocean is in the Sunda Trench (7729 m).

• Area: 76,170 thousand km²
• Volume: 282,650 thousand km³
• Maximum depth: 7729 m
• Average depth: 3711 m

In the north it washes Asia, in the west - Africa, in the east - Australia; in the south it borders on Antarctica. The border with the Atlantic Ocean runs along the 20 ° meridian of east longitude; from the Pacific - along the 146 ° 55 'meridian of eastern longitude. The northernmost point of the Indian Ocean is located at approximately 30° north latitude in the Persian Gulf. The width of the Indian Ocean is approximately 10,000 km between the southern points of Australia and Africa.

Etymology

The ancient Greeks called the western part of the ocean known to them with adjacent seas and bays the Erythrean Sea (ancient Greek Ἐρυθρά θάλασσα - Red Sea, and in old Russian sources the Red Sea). Gradually, this name began to be attributed only to the nearest sea, and the ocean gets its name from India, the country most famous at that time for its wealth on the shores of the ocean. So Alexander the Great in the IV century BC. e. calls it Indicon Pelagos (ancient Greek Ἰνδικόν πέλαγος) - "Indian Sea". Among the Arabs, it is known as Bar-el-Hind (modern Arabic المحيط الهندي‎‎ - al-mụkhіt al-hindi) - "Indian Ocean". Since the 16th century, the name Oceanus Indicus (lat. Oceanus Indicus) introduced by the Roman scientist Pliny the Elder back in the 1st century was established - the Indian Ocean.

Physical and geographical characteristics

General information

The Indian Ocean is mainly located south of the Tropic of Cancer between Eurasia to the north, Africa to the west, Australia to the east and Antarctica to the south. The border with the Atlantic Ocean runs along the meridian of Cape Agulhas (20 ° E to the coast of Antarctica (Queen Maud Land)). The border with the Pacific Ocean runs: south of Australia - along the eastern border of the Bass Strait to the island of Tasmania, then along the meridian 146 ° 55 'E. to Antarctica; north of Australia - between the Andaman Sea and the Strait of Malacca, further along the southwestern coast of Sumatra, the Sunda Strait, the southern coast of Java, the southern borders of the Bali and Savu seas, the northern border of the Arafura Sea, the southwestern coast of New Guinea and the western border of the Torres Strait . Sometimes the southern part of the ocean, with a northern boundary of 35 ° S. sh. (on the basis of the circulation of water and the atmosphere) up to 60 ° S. sh. (according to the nature of the bottom topography), they are attributed to the Southern Ocean, which is not officially distinguished.

Seas, bays, islands

The area of ​​the seas, bays and straits of the Indian Ocean is 11.68 million km² (15% of the total ocean area), the volume is 26.84 million km³ (9.5%). The seas and main bays located along the coast of the ocean (clockwise): Red Sea, Arabian Sea (Gulf of Aden, Gulf of Oman, Persian Gulf), Laccadive Sea, Bay of Bengal, Andaman Sea, Timor Sea, Arafura Sea (Gulf of Carpentaria), Large Australian Gulf, Mawson Sea, Davis Sea, Commonwealth Sea, Astronaut Sea (the last four are sometimes referred to as the Southern Ocean).

Some islands - for example, Madagascar, Socotra, Maldives - are fragments of ancient continents, others - Andaman, Nicobar or Christmas Island - are of volcanic origin. The largest island in the Indian Ocean is Madagascar (590 thousand km²). Largest islands and archipelagos: Tasmania, Sri Lanka, Kerguelen Archipelago, Andaman Islands, Melville, Mascarene Islands (Reunion, Mauritius), Kangaroo, Nias, Mentawai Islands (Siberut), Socotra, Groot Island, Comoros, Tiwi Islands (Bathurst ), Zanzibar, Simeulue, Furno (Flinders) Islands, Nicobar Islands, Qeshm, King, Bahrain Islands, Seychelles, Maldives, Chagos Archipelago.

The history of the formation of the Indian Ocean

During the early Jurassic, the ancient supercontinent Gondwana began to break apart. As a result, Africa with Arabia, Hindustan and Antarctica with Australia were formed. The process ended at the turn of the Jurassic and Cretaceous periods (140-130 million years ago), and a young basin of the modern Indian Ocean began to form. In the Cretaceous period, the ocean floor grew due to the movement of Hindustan to the north and the reduction in the area of ​​the Pacific and Tethys oceans. In the Late Cretaceous, the split of the single Australo-Antarctic continent began. At the same time, as a result of the formation of a new rift zone, the Arabian plate broke away from the African plate, and the Red Sea and the Gulf of Aden were formed. At the beginning of the Cenozoic era, the growth of the Indian Ocean stopped towards the Pacific, but continued towards the Tethys Sea. At the end of the Eocene - the beginning of the Oligocene, Hindustan collided with the Asian continent.

Today, the movement of tectonic plates continues. The axis of this movement is the mid-ocean rift zones of the African-Antarctic Ridge, the Central Indian Ridge, and the Australo-Antarctic Rise. The Australian plate continues to move north at a rate of 5-7 cm per year. The Indian plate continues to move in the same direction at a speed of 3-6 cm per year. The Arabian Plate is moving northeast at a rate of 1-3 cm per year. The Somali Plate continues to break away from the African Plate along the East African Rift Zone, which moves at a speed of 1-2 cm per year in a northeasterly direction. On December 26, 2004, in the Indian Ocean near the island of Simeulue, located off the northwestern coast of the island of Sumatra (Indonesia), the largest earthquake with a magnitude of up to 9.3 occurred in the entire history of observations. The reason was a shift of about 1200 km (according to some estimates - 1600 km) of the earth's crust at a distance of 15 m along the subduction zone, as a result of which the Hindustan plate moved under the Burma plate. The earthquake caused a tsunami, which brought enormous destruction and a huge number of deaths (up to 300 thousand people).

Geological structure and topography of the bottom of the Indian Ocean

mid-ocean ridges

Mid-ocean ridges divide the bottom of the Indian Ocean into three sectors: African, Indo-Australian and Antarctic. There are four mid-ocean ridges: the West Indian, Arabian-Indian, Central Indian ridges and the Australo-Antarctic Rise. The West Indian Ridge is located in the southwestern part of the ocean. It is characterized by underwater volcanism, seismicity, rift-type crust and rift structure of the axial zone; it is crossed by several oceanic faults of submeridional strike. In the region of the island of Rodrigues (Mascarene archipelago) there is a so-called triple connection, where the system of ridges is divided to the north into the Arabian-Indian ridge and to the south-west into the Central Indian ridge. The Arabian-Indian ridge is composed of ultramafic rocks, a number of submeridial-trending secant faults have been identified, with which very deep depressions (oceanic troughs) with depths of up to 6.4 km are associated. The northern part of the ridge is crossed by the most powerful Owen Fault, along which the northern segment of the ridge experienced a displacement of 250 km to the north. Further west, the rift zone continues into the Gulf of Aden and north-northwest into the Red Sea. Here the rift zone is composed of carbonate deposits with volcanic ash. In the rift zone of the Red Sea, strata of evaporites and metal-bearing silts were found associated with powerful hot (up to 70 °C) and very saline (up to 350 ‰) juvenile waters.

In the southwest direction from the triple junction extends the Central Indian Ridge, which has a well-defined rift and flank zones, ending in the south with the Amsterdam volcanic plateau with the volcanic islands of Saint-Paul and Amsterdam. From this plateau, the Australo-Antarctic Rise extends to the east-southeast, having the form of a wide, slightly dissected arch. In the eastern part, the uplift is dissected by a series of meridional faults into a number of segments displaced relative to each other in the meridional direction.

African segment of the ocean

The underwater margin of Africa has a narrow shelf and a distinct continental slope with marginal plateaus and continental foot. In the south, the African continent forms protrusions pushed to the south: the Agulhas bank, the Mozambique and Madagascar ridges, composed of continental-type earth's crust. The mainland foot forms a sloping plain extending south along the coast of Somalia and Kenya, which continues in the Mozambique Channel and borders Madagascar from the east. The Mascarene Range runs along the east of the sector, in the northern part of which the Seychelles are located.

The surface of the ocean floor in the sector, especially along the mid-ocean ridges, is dissected by numerous ridges and troughs associated with submeridional fault zones. There are many underwater volcanic mountains, most of which are built on coral superstructures in the form of atolls and underwater coral reefs. Between the mountain rises there are basins of the ocean floor with a hilly and mountainous relief: Agulhas, Mozambique, Madagascar, Mascarene and Somali. In the Somali and Mascarene basins, vast flat abyssal plains are formed, where a significant amount of terrigenous and biogenic sedimentary material enters. In the Mozambique Basin, there is an underwater valley of the Zambezi River with a system of alluvial fans.

Indo-Australian segment of the ocean

The Indo-Australian segment occupies half the area of ​​the Indian Ocean. In the west, in the meridional direction, the Maldives Range passes, on the top surface of which the islands of Laccadive, Maldives and Chagos are located. The ridge is composed of continental-type crust. A very narrow shelf, a narrow and steep continental slope, and a very wide continental foot stretched along the coast of Arabia and Hindustan, mainly formed by two giant fans of turbid streams of the Indus and Ganges rivers. These two rivers carry 400 million tons of debris into the ocean. The Indus cone extends far into the Arabian Basin. And only the southern part of this basin is occupied by a flat asbyssal plain with separate seamounts.

Almost exactly 90° E. The blocky oceanic East Indian Ridge stretches for 4,000 km from north to south. Between the Maldives and the East Indian Ranges is the Central Basin - the largest basin of the Indian Ocean. Its northern part is occupied by the Bengal alluvial fan (from the Ganges River), to the southern border of which the abyssal plain adjoins. In the central part of the basin there is a small Lanka ridge and the Afanasy Nikitin seamount. To the east of the East Indian Ridge are the Cocos and Western Australian Basins, separated by a blocky sublatitudinally oriented Cocos Rise with the Cocos and Christmas Islands. In the northern part of the Coconut Basin there is a flat abyssal plain. From the south, it is bounded by the West Australian Rise, which drops steeply to the south and gently plunges under the bottom of the basin to the north. From the south, the West Australian Rise is bounded by a steep ledge associated with the Diamantina Fault Zone. The ralome zone combines deep and narrow grabens (the most significant are the Ob and Diamatina) and numerous narrow horsts.

The transitional region of the Indian Ocean is represented by the Andaman Trench and the deep-sea Sunda Trench, which is associated with the maximum depth of the Indian Ocean (7209 m). The outer ridge of the Sunda island arc is the underwater Mentawai Range and its continuation in the form of the Andaman and Nicobar Islands.

Underwater margin of the Australian mainland

The northern part of the Australian continent is bordered by a wide Sahul shelf with many coral structures. To the south, this shelf narrows and widens again off the coast of southern Australia. The continental slope is composed of marginal plateaus (the largest of them are the Exmouth and Naturalists plateaus). In the western part of the Western Australian Basin, the Zenith, Cuvier and other rises are located, which are pieces of the continental structure. Between the southern underwater margin of Australia and the Australo-Antarctic Rise, there is a small South Australian Basin, which is a flat abyssal plain.

Antarctic segment of the ocean

The Antarctic segment is bounded by the West Indian and Central Indian ridges, and from the south by the coast of Antarctica. Under the influence of tectonic and glaciological factors, the shelf of Antarctica is overdeepened. A wide continental slope is cut by large and wide canyons, through which supercooled water flows from the shelf into the abyssal depressions. The continental foot of Antarctica is distinguished by a wide and significant (up to 1.5 km) thickness of loose deposits.

The largest protrusion of the Antarctic continent is the Kerguelen Plateau, as well as the volcanic uplift of the Prince Edward and Crozet Islands, which divide the Antarctic sector into three basins. To the west is the African-Antarctic Basin, which is half located in the Atlantic Ocean. Most of its bottom is a flat abyssal plain. The Crozet Basin, located to the north, is characterized by a large-hilly bottom topography. The Australo-Antarctic Basin, lying to the east of Kerguelen, is occupied in the southern part by a flat plain, and in the northern part by Abyssotian hills.

Bottom sediments

The Indian Ocean is dominated by calcareous foraminiferal-coccolithic deposits, which occupy more than half of the bottom area. The wide development of biogenic (including coral) calcareous deposits is explained by the position of a large part of the Indian Ocean within the tropical and equatorial belts, as well as by the relatively shallow depth of oceanic basins. Numerous mountain uplifts are also favorable for the formation of lime deposits. In the deep parts of some basins (for example, the Central, Western Australian), deep-sea red clays occur. The equatorial belt is characterized by radiolarian muds. In the southern cold part of the ocean, where the conditions for the development of diatom flora are especially favorable, siliceous diatom deposits are represented. Iceberg sediments are deposited off the Antarctic coast. At the bottom of the Indian Ocean, ferromanganese nodules are widely distributed, confined mainly to areas of deposition of red clays and radiolarian oozes.

Climate

In this region, four climatic zones are distinguished, stretched along the parallels. Under the influence of the Asian continent, a monsoonal climate is established in the northern part of the Indian Ocean with frequent cyclones moving towards the coasts. High atmospheric pressure over Asia in winter causes the northeast monsoon to form. In summer, it is replaced by a humid southwest monsoon, carrying air from the southern regions of the ocean. During the summer monsoon, there is often a wind force of more than 7 points (with a frequency of 40%). In summer, the temperature over the ocean is 28-32 °C, in winter it drops to 18-22 °C.

In the southern tropics, the southeast trade wind dominates, which in winter does not extend north of 10°N. The average annual temperature reaches 25 °C. In the zone 40-45°S. Throughout the year, the western transfer of air masses is characteristic, it is especially strong in temperate latitudes, where the frequency of storm weather is 30-40%. In the mid-ocean, stormy weather is associated with tropical hurricanes. In winter, they can also occur in the southern tropical zone. Most often, hurricanes occur in the western part of the ocean (up to 8 times a year), in the areas of Madagascar and the Mascarene Islands. In subtropical and temperate latitudes, the temperature reaches 10-22 °C in summer and 6-17 °C in winter. Strong winds are characteristic from 45 degrees and south. In winter, the temperature here ranges from -16 °C to 6 °C, and in summer - from -4 °C to 10 °C.

The maximum amount of precipitation (2.5 thousand mm) is confined to the eastern region of the equatorial zone. There is also increased cloudiness (more than 5 points). The least amount of precipitation is observed in the tropical regions of the southern hemisphere, especially in the eastern part. In the northern hemisphere, clear weather is characteristic of the Arabian Sea for most of the year. The maximum cloudiness is observed in Antarctic waters.

Hydrological regime of the Indian Ocean

Surface water circulation

In the northern part of the ocean, there is a seasonal change in currents caused by monsoon circulation. In winter, the Southwest Monsoon Current sets in, starting in the Bay of Bengal. South of 10° N. sh. this current passes into the Western Current, crossing the ocean from the Nicobar Islands to the coast of East Africa. Further, it branches: one branch goes north to the Red Sea, the other - south to 10 ° S. sh. and, turning to the east, gives rise to the Equatorial countercurrent. The latter crosses the ocean and, off the coast of Sumatra, again divides into a part that goes into the Andaman Sea and the main branch, which between the Lesser Sunda Islands and Australia goes to the Pacific Ocean. In summer, the southeast monsoon ensures the movement of the entire mass of surface water to the east, and the Equatorial countercurrent disappears. The summer monsoon current begins off the coast of Africa with the powerful Somali current, which is joined by the current from the Red Sea in the Gulf of Aden. In the Bay of Bengal, the summer monsoon current divides into north and south, which flows into the South Equatorial Current.

In the southern hemisphere, currents are constant, without seasonal fluctuations. Driven by the trade winds, the South Trade Wind Current crosses the ocean from east to west towards Madagascar. It intensifies in winter (for the southern hemisphere) due to additional feeding by the waters of the Pacific Ocean coming along the northern coast of Australia. At Madagascar, the South Equatorial Current forks, giving rise to the Equatorial Countercurrent, Mozambique and Madagascar currents. Merging southwest of Madagascar, they form the warm Agulhas current. The southern part of this current goes into the Atlantic Ocean, and part of it flows into the westerly winds. On the approach to Australia, the cold West Australian Current departs from the latter to the north. Local gyres operate in the Arabian Sea, the Bengal and Great Australian Bays, and in Antarctic waters.

The northern part of the Indian Ocean is characterized by the predominance of a semidiurnal tide. The amplitudes of the tide in the open ocean are small and average 1 m. In the Antarctic and subantarctic zones, the amplitude of the tides decreases from east to west from 1.6 m to 0.5 m, and near the coast they increase to 2-4 m. The maximum amplitudes are noted between islands, in shallow bays. In the Bay of Bengal, the tide is 4.2-5.2 m, near Mumbai - 5.7 m, near Yangon - 7 m, near northwestern Australia - 6 m, and in the port of Darwin - 8 m. In other areas, the amplitude of the tides about 1-3 m.

temperature, salinity

In the equatorial zone of the Indian Ocean, the surface water temperature is about 28 ° C all year round in both the western and eastern parts of the ocean. In the Red and Arabian Seas, winter temperatures drop to 20-25 °C, but in summer the maximum temperatures for the entire Indian Ocean are set in the Red Sea - up to 30-31 °C. High winter water temperatures (up to 29 ° C) are typical for the coasts of northwestern Australia. In the southern hemisphere, at the same latitudes in the eastern part of the ocean, the water temperature in winter and summer is 1-2° lower than in the western part. Water temperatures below 0°C in summer are found south of 60°S. sh. Ice formation in these areas begins in April, and the fast ice thickness reaches 1-1.5 m by the end of winter. Melting begins in December-January, and by March, fast ice is completely cleared of water. In the southern part of the Indian Ocean, icebergs are common, sometimes setting north of 40 ° S. sh.

The maximum salinity of surface waters is observed in the Persian Gulf and the Red Sea, where it reaches 40-41 ‰. High salinity (more than 36 ‰) is also observed in the southern tropical zone, especially in the eastern regions, and in the northern hemisphere also in the Arabian Sea. In the neighboring Bay of Bengal, due to the desalination effect of the Ganges runoff from the Brahmaputra and the Irrawaddy, the salinity is reduced to 30-34 ‰. Increased salinity correlates with areas of maximum evaporation and the least amount of precipitation. Reduced salinity (less than 34 ‰) is characteristic of subarctic waters, where the strong freshening effect of melted glacial waters is felt. The seasonal difference in salinity is significant only in the Antarctic and equatorial zones. In winter, desalinated waters from the northeastern part of the ocean are carried by the monsoon current, forming a tongue of low salinity along 5°N. sh. In summer, this language disappears. In the Arctic waters in winter, salinity slightly increases due to the salinization of waters in the process of ice formation. Salinity decreases from the surface to the bottom of the ocean. Bottom waters from the equator to the arctic latitudes have a salinity of 34.7-34.8 ‰.

water masses

The waters of the Indian Ocean are divided into several water masses. In the part of the ocean north of 40 ° S. sh. they distinguish central and equatorial surface and subsurface water masses and underlying them (deeper than 1000 m) deep. To the north to 15-20 ° S. sh. the central water mass spreads. The temperature varies with depth from 20-25 °C to 7-8 °C, salinity is 34.6-35.5 ‰. Surface layers north of 10-15°S sh. make up the equatorial water mass with a temperature of 4-18 ° C and a salinity of 34.9-35.3 ‰. This water mass is characterized by significant speeds of horizontal and vertical movement. In the southern part of the ocean, there are subantarctic (temperature 5-15 ° C, salinity up to 34 ‰) and Antarctic (temperature from 0 to -1 ° C, salinity drops to 32 ‰ due to melting ice). Deep water masses are divided into: very cold circulation, formed by lowering the Arctic water masses and the inflow of circulation water from the Atlantic Ocean; South Indian, formed as a result of lowering subarctic surface waters; North Indian, formed by dense waters flowing from the Red Sea and the Gulf of Oman. Deeper than 3.5-4 thousand m, bottom water masses are common, formed from the Antarctic supercooled and dense salt waters of the Red Sea and the Persian Gulf.

Flora and fauna

The flora and fauna of the Indian Ocean is extremely diverse. The tropical region stands out for its abundance of plankton. The single-celled alga Trichodesmium (cyanobacteria) is especially abundant, due to which the surface layer of water becomes very cloudy and changes its color. The plankton of the Indian Ocean is distinguished by a large number of night-luminous organisms: peridine, some species of jellyfish, ctenophores, and tunicates. Brightly colored siphonophores, including poisonous physalia, are abundant. In temperate and arctic waters, the main representatives of plankton are copepods, euphausids and diatoms. The most numerous fish of the Indian Ocean are dolphins, tuna, notothenia and various sharks. From reptiles there are several species of giant sea turtles, sea snakes, from mammals - cetaceans (toothless and blue whales, sperm whales, dolphins), seals, sea elephants. Most cetaceans live in temperate and polar regions, where, due to the intensive mixing of waters, favorable conditions arise for the development of planktonic organisms. Birds are represented by albatrosses and frigatebirds, as well as several species of penguins that inhabit the coasts of South Africa, Antarctica and islands in the temperate ocean.

The flora of the Indian Ocean is represented by brown algae (Sargasso, Turbinarium) and green algae (Caulerpa). The calcareous algae lithotamnia and chalimeda also flourish and participate together with corals in the construction of reef structures. In the process of activity of reef-forming organisms, coral platforms are created, sometimes reaching a width of several kilometers. Typical for the coastal zone of the Indian Ocean is a phytocenosis formed by mangroves. Such thickets are especially characteristic of river mouths and occupy large areas in Southeast Africa, western Madagascar, Southeast Asia and other regions. For temperate and Antarctic waters, the most characteristic are red and brown algae, mainly from the groups of fucus and kelp, porphyry, and helidium. In the subpolar regions of the southern hemisphere, giant macrocystis are found.

Zoobenthos is represented by a variety of mollusks, calcareous and flint sponges, echinoderms (sea urchins, starfish, brittle stars, holothurians), numerous crustaceans, hydroids, and bryozoans. Coral polyps are widespread in the tropical zone.

Ecological problems

Human economic activity in the Indian Ocean has led to the pollution of its waters and to the reduction of biodiversity. At the beginning of the 20th century, some species of whales were almost completely exterminated, others - sperm whales and sei whales - still survived, but their number was greatly reduced. Since the 1985-1986 season, the International Whaling Commission has introduced a complete moratorium on commercial whaling of any kind. In June 2010, at the 62nd meeting of the International Whaling Commission, under pressure from Japan, Iceland and Denmark, the moratorium was suspended. The Mauritius dodo, destroyed by 1651 on the island of Mauritius, became a symbol of extinction and extinction of species. After it became extinct, people first formed the opinion that they could cause the extinction of other animals.

A great danger in the ocean is the pollution of waters with oil and oil products (the main pollutants), some heavy metals, and waste from the nuclear industry. The routes of oil tankers transporting oil from the countries of the Persian Gulf run across the ocean. Any major accident can lead to an ecological disaster and the death of many animals, birds and plants.

States of the Indian Ocean

States along the borders of the Indian Ocean (clockwise):

• Republic Of South Africa,
• Mozambique,
• Tanzania,
• Kenya,
• Somalia,
• Djibouti,
• Eritrea,
• Sudan,
• Egypt,
• Israel,
• Jordan,
• Saudi Arabia,
• Yemen,
• Oman,
• United Arab Emirates,
• Qatar,
• Kuwait,
• Iraq,
• Iran,
• Pakistan,
• India,
• Bangladesh,
• Myanmar,
• Thailand,
• Malaysia,
• Indonesia,
• East Timor,
• Australia.

In the Indian Ocean there are island states and possessions of states outside the region:

• Bahrain,
• British Indian Ocean Territory (UK),
• Comoros,
• Mauritius,
• Madagascar,
• Mayotte (France),
• Maldives,
• Reunion (France),
• Seychelles,
• French Southern and Antarctic Territories (France),
• Sri Lanka.

Research History

The shores of the Indian Ocean are one of the areas of settlement of the most ancient peoples and the emergence of the first river civilizations. In ancient times, ships such as junks and catamarans were used by people for sailing, with favorable monsoons from India to East Africa and back. The Egyptians in 3500 BC conducted a brisk maritime trade with the countries of the Arabian Peninsula, India and East Africa. The countries of Mesopotamia for 3000 years BC made sea trips to Arabia and India. From the 6th century BC, the Phoenicians, according to the Greek historian Herodotus, made sea voyages from the Red Sea across the Indian Ocean to India and around Africa. In the 6th-5th centuries BC, Persian merchants conducted maritime trade from the mouth of the Indus River along the east coast of Africa. At the end of the Indian campaign of Alexander the Great in 325 BC, the Greeks with a huge fleet with a crew of five thousand in severe storm conditions made a many-month voyage between the mouths of the Indus and Euphrates rivers. Byzantine merchants in the 4th-6th centuries penetrated in the east to India, and in the south - to Ethiopia and Arabia. Starting from the 7th century, Arab sailors began intensive exploration of the Indian Ocean. They perfectly studied the coast of East Africa, West and East India, the islands of Socotra, Java and Ceylon, visited the Laccadives and Maldives, the islands of Sulawesi, Timor and others.

At the end of the 13th century, the Venetian traveler Marco Polo, on his way back from China, passed through the Indian Ocean from Malacca to the Strait of Hormuz, visiting Sumatra, India, and Ceylon. The journey was described in the Book of the Diversity of the World, which had a significant impact on navigators, cartographers, and writers of the Middle Ages in Europe. Chinese junks made trips along the Asian shores of the Indian Ocean and reached the Eastern coast of Africa (for example, Zheng He's seven voyages in 1405-1433). The expedition, led by the Portuguese navigator Vasco da Gama, rounded Africa from the south, passing along the eastern coast of the continent in 1498, reached India. In 1642, the Dutch trading East India Company organized an expedition of two ships under the command of Captain Tasman. As a result of this expedition, the central part of the Indian Ocean was explored and it was proved that Australia is the mainland. In 1772, a British expedition under the command of James Cook penetrated the southern Indian Ocean to 71°S. sh., while extensive scientific material on hydrometeorology and oceanography was obtained.

From 1872 to 1876, the first scientific oceanic expedition took place on the English sailing steam corvette Challenger, new data were obtained on the composition of the ocean waters, on the flora and fauna, on the bottom topography and soils, the first map of the depths of the ocean was compiled and the first collection was collected deep sea animals. A round-the-world expedition on the Russian propeller-sailing corvette "Vityaz" of 1886-1889, led by oceanographer S. O. Makarov, conducted a large-scale research work in the Indian Ocean. A great contribution to the study of the Indian Ocean was made by oceanographic expeditions on the German ships Valkyrie (1898-1899) and Gauss (1901-1903), on the English ship Discovery II (1930-1951), the Soviet expeditionary ship Ob ( 1956-1958) and others. In 1960-1965, under the auspices of the Intergovernmental Oceanographic Expedition under UNESCO, an international Indian Ocean Expedition was carried out. She was the largest of all the expeditions ever to work in the Indian Ocean. The program of oceanographic work covered almost the entire ocean with observations, which was facilitated by the participation of scientists from about 20 countries in the research. Among them: Soviet and foreign scientists on the research ships Vityaz, A. I. Voeikov”, “Yu. M. Shokalsky, non-magnetic schooner Zarya (USSR), Natal (South Africa), Diamantina (Australia), Kistna and Varuna (India), Zulfikvar (Pakistan). As a result, valuable new data were collected on hydrology, hydrochemistry, meteorology, geology, geophysics and biology of the Indian Ocean. Since 1972, the American ship Glomar Challenger has carried out regular deep-sea drilling, work on the study of the movement of water masses at great depths, and biological research.

In recent decades, numerous measurements of the ocean have been carried out using space satellites. The result was a bathymetric atlas of the oceans released in 1994 by the US National Geophysical Data Center with a map resolution of 3-4 km and a depth accuracy of ±100 m.

Economic importance

Fishing and marine industries

The importance of the Indian Ocean for the world fishing industry is small: the catches here are only 5% of the total. The main commercial fish of the local waters are tuna, sardine, anchovy, several species of sharks, barracudas and rays; Shrimps, lobsters and lobsters are also caught here. Until recently, whaling, which was intensive in the southern regions of the ocean, is rapidly curtailing due to the almost complete extermination of some species of whales. On the northwestern coast of Australia, in Sri Lanka and the Bahrain Islands, pearls and mother-of-pearl are mined.

Transport routes

The most important transport routes of the Indian Ocean are routes from the Persian Gulf to Europe, North America, Japan and China, as well as from the Gulf of Aden to India, Indonesia, Australia, Japan and China. The main navigable straits of the Indian Strait: Mozambique, Bab-el-Mandeb, Hormuz, Sunda. The Indian Ocean is connected by the artificial Suez Canal to the Mediterranean Sea of ​​the Atlantic Ocean. In the Suez Canal and the Red Sea, all the main cargo flows of the Indian Ocean converge and diverge. Major ports: Durban, Maputo (export: ore, coal, cotton, minerals, oil, asbestos, tea, raw sugar, cashew nuts, import: machinery and equipment, manufactured goods, food), Dar es Salaam (export : cotton, coffee, sisal, diamonds, gold, petroleum products, cashew nuts, cloves, tea, meat, leather, import: manufactured goods, food, chemicals), Jeddah, Salalah, Dubai, Bandar Abbas, Basra (export: oil, grain, salt, dates, cotton, leather, import: cars, timber, textiles, sugar, tea), Karachi (export: cotton, fabrics, wool, leather, shoes, carpets, rice, fish, import: coal, coke, oil products , mineral fertilizers, equipment, metals, grain, food, paper, jute, tea, sugar), Mumbai (export: manganese and iron ores, oil products, sugar, wool, leather, cotton, fabrics, import: oil, coal, cast iron, equipment, grain, chemicals, manufactured goods), Colombo, Chennai (iron ore, coal, granite, fertilizers, petroleum products, containers, vehicles), Kolkata (export: coal, iron and copper ores, tea, imports: manufactured goods, grain, foodstuffs, equipment), Chittagong (clothing, jute, leather, tea, chemicals), Yangon (exports: rice, hardwood, non-ferrous metals, bagasse, legumes, rubber, precious stones, import: coal, cars, foodstuffs, fabrics), Perth Fremantle (export: ores, alumina, coal, coke, caustic soda, phosphate raw materials, import: oil, equipment).

Minerals

The most important minerals of the Indian Ocean are oil and natural gas. Their deposits are found on the shelves of the Persian and Suez Gulfs, in the Bass Strait, on the shelf of the Hindustan Peninsula. On the coasts of India, Mozambique, Tanzania, South Africa, the islands of Madagascar and Sri Lanka, ilmenite, monazite, rutile, titanite and zirconium are exploited. There are deposits of barite and phosphorite off the coast of India and Australia, and deposits of cassiterite and ilmenite are exploited on an industrial scale in the shelf zones of Indonesia, Thailand and Malaysia.

Recreational resources

The main recreational areas of the Indian Ocean: the Red Sea, the western coast of Thailand, the islands of Malaysia and Indonesia, the island of Sri Lanka, the area of ​​coastal urban agglomerations of India, the eastern coast of Madagascar, the Seychelles and Maldives. Among the countries of the Indian Ocean with the largest flow of tourists (according to 2010 data from the World Tourism Organization) stand out: Malaysia (25 million visits per year), Thailand (16 million), Egypt (14 million), Saudi Arabia (11 million), South Africa (8 million), United Arab Emirates (7 million), Indonesia (7 million), Australia (6 million), India (6 million), Qatar (1.6 million), Oman (1.5 million).

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