Introduction

1.History of the formation and exploration of the Indian Ocean

2.General information about the Indian Ocean

Bottom relief.

.Characteristics of the waters of the Indian Ocean.

.Bottom sediments of the Indian Ocean and its structure

.Minerals

.Indian Ocean climate

.Vegetable and animal world

.Fishing and marine industry

Introduction

Indian Ocean - the youngest and warmest among the world's oceans. Most of it is located in the southern hemisphere, and in the north it extends far into the mainland, which is why the ancient people considered it to be just a large sea. It was here, in the Indian Ocean, that man began his first sea voyages.

The largest rivers of Asia belong to the Indian Ocean basin: Salween, Ayeyarwaddy and Ganges with Brahmaputra, flowing into the Bay of Bengal; Indus, which flows into the Arabian Sea; Tigris and Euphrates, merging slightly above the confluence of the Persian Gulf. Of the major rivers in Africa, also flowing into the Indian Ocean, the Zambezi and Limpopo should be named. Because of them, the water off the coast of the ocean is muddy, with a high content sedimentary rocks- sand, silt and clay. But the open ocean waters are strikingly clear. The tropical islands of the Indian Ocean are renowned for their cleanliness. A variety of animals have found their place on coral reefs. The Indian Ocean is home to the famous sea devils, rare whale sharks, bigmouths, sea cows, sea snakes, and more.

1. History of formation and research

Indian Oceanformed at the junction of the Jurassic and Cretaceous periods as a result of the collapse of Gondwana (130-150 million years ago). Then there was the separation of Africa and the Deccan from Australia with Antarctica, and later - Australia from Antarctica (in the Paleogene, about 50 million years ago).

The Indian Ocean and its shores remain poorly understood. The name of the Indian Ocean is found already at the beginning of the XVI century. in Schoener under the name Oceanus orientalis indicus, in contrast to the Atlantic Ocean, then known as Oceanus occidentalis. Subsequent geographers called the Indian Ocean for the most part the sea of ​​India, some (Varenius) the Australian Ocean, and Fleurie recommended (in the XVIII century) to call it even the Great Indian Gulf, considering it as part of the Pacific Ocean.

In ancient times (3000-1000 BC) sailors from India, Egypt and Phenicia traveled in the northern part of the Indian Ocean. The first navigational charts were compiled by the ancient Arabs. At the end of the 15th century, the first European - the famous Portuguese Vasco da Gama, circled Africa from the south, entered the waters of the Indian Ocean. By the 16th-17th centuries, Europeans (Portuguese, and later the Dutch, French and British) increasingly appeared in the Indian Ocean basin, and by the middle of the 19th century, most of its shores and islands were already the property of Great Britain.

Discovery historycan be divided into 3 periods: from ancient voyages to 1772; from 1772 to 1873 and from 1873 to the present. The first period is characterized by the study of the distribution of ocean and land waters in this part of the world. It began with the first voyages of Indian, Egyptian and Phoenician seafarers, who in 3000-1000 BC. traveled in the northern part of the Indian Ocean, and ended with the voyage of J. Cook, who in 1772-75 penetrated the South to 71 ° S. NS.

The second period was marked by the beginning of deep-sea research, first carried out by Cook in 1772 and continued by Russian and foreign expeditions. The main Russian expeditions were - O. Kotzebue on the "Rurik" (1818) and Pallena on the "Cyclone" (1858-59).

The third period is characterized by comprehensive oceanographic research. Until 1960, they were carried out on separate ships. The largest works were carried out by expeditions on the ships Challenger (English) in 1873-74, Vityaz (Russian) in 1886, Valdivia (German) in 1898-99 and Gauss (German) in 1901-03, Discovery II (English) in 1930-51, the Soviet expedition to the Ob in 1956-58, and others. In 1960-65, the Intergovernmental Oceanographic Expedition at UNESCO conducted an international Indian Ocean expedition that collected new valuable data on hydrology, hydrochemistry, meteorology , geology, geophysics and biology of the Indian Ocean.

... General information

Indian Ocean- the third largest ocean on Earth (after the Pacific and Atlantic), covering about 20% of its water surface. Almost all of them are located in the southern hemisphere. Its area is 74,917 thousand km ² ; average volume of water - 291,945 thousand km ³. In the north it is bounded by Asia, in the west by the Arabian Peninsula and Africa, in the east by Indochina, the Sunda Islands and Australia, in the south by the Southern Ocean. The border between the Indian and Atlantic oceans runs along the 20 ° meridian east longitude (meridian of Cape Agulhas), between the Indian and The Pacific Ocean runs along 147 ° east longitude (meridian of the southern promontory of Tasmania). The northernmost point of the Indian Ocean is located at about 30 ° north latitude in the Persian Gulf. The Indian Ocean is approximately 10,000 km wide between the southern points of Australia and Africa.

The greatest depth of the Indian Ocean is the Sunda, or Javan trench (7729 m), the average depth is 3700 m.

The Indian Ocean is washed by three continents at once: Africa from the east, Asia from the south, Australia from the north and northwest.

The Indian Ocean has the smallest number of seas compared to other oceans. In the northern part, the most large seas: Mediterranean - the Red Sea and the Persian Gulf, the semi-enclosed Andaman Sea and the marginal Arabian Sea; in the eastern part - the Arafur and Timor seas.

The Indian Ocean is home to the island states of Madagascar (the fourth largest island in the world), Sri Lanka, Maldives, Mauritius, Comoros, Seychelles. The ocean is washed in the east by the following states: Australia, Indonesia; in the north-east: Malaysia, Thailand, Myanmar; in the north: Bangladesh, India, Pakistan; in the west: Oman, Somalia, Kenya, Tanzania, Mozambique, South Africa. In the south, it borders on Antarctica. There are relatively few islands. In the open part of the ocean there are volcanic islands - Mascarensky, Crozet, Prince Edward, etc. In tropical latitudes, coral islands rise on volcanic cones - the Maldives, Lakkadiv, Chagos, Cocos, most of the Andaman, etc.

... Bottom relief

The ocean floor is a system of mid-ocean ridges and basins. In the area of ​​Rodriguez Island (Mascarene Archipelago), there is a so-called triple junction, where the Central Indian and West Indian ridges converge, as well as the Austral-Antarctic uplift. The ridges consist of steep mountain ranges, cut by faults perpendicular or oblique to the chain axes and divide the basalt ocean floor into 3 segments, and their tops are, as a rule, extinct volcanoes. The bottom of the Indian Ocean is covered with sediments of the Cretaceous and later periods, the layer thickness of which ranges from several hundred meters to 2-3 km. The deepest of the many ocean trenches is Yavan (4,500 km long and 29 km wide). The rivers flowing into the Indian Ocean carry with them huge amounts of sedimentary material, especially from India, creating high alluvial rapids.

The Indian Ocean coastline is replete with cliffs, deltas, atolls, coastal coral reefs and mangrove saline marshes. Some islands - for example, Madagascar, Socotra, Maldives - are fragments of ancient continents.In the open part of the Indian Ocean, numerous islands and archipelagos of volcanic origin are scattered. In the northern part of the ocean, many of them are crowned with coral structures. Andaman, Nicobar or Christmas Island are of volcanic origin. The Kerguelen Plateau, located in the southern part of the ocean, is also of volcanic origin.

An underwater Indian Ocean earthquake on December 26, 2004 triggered a tsunami that was considered deadliest natural disaster v modern history... The magnitude of the earthquake was, according to various estimates, from 9.1 to 9.3. This is the second or third strongest earthquake in the entire history of observation.

The epicenter of the earthquake was in the Indian Ocean, north of the island of Simeolue, located off the northwestern coast of the island of Sumatra (Indonesia). The tsunami reached the shores of Indonesia, Sri Lanka, southern India, Thailand and other countries. The wave height exceeded 15 meters. The tsunami led to tremendous destruction and a huge number of dead people, even in Port Elizabeth, South Africa, 6900 km from the epicenter. Killed, according to various estimates, from 225 thousand to 300 thousand people. True number the death toll is unlikely to ever be known, as many people were carried away by the water into the sea.

As for the properties of the bottom soil, then, as in other oceans, sediments on the bottom of the Indian Ocean can be divided into three classes: coastal sediments, organic silt (globigerin, radiolar or diatomaceous) and a special clay of great depths, the so-called red clay. Coastal sediments are sand, located mostly on coastal shoals to a depth of 200 meters, green or blue silt near rocky shores, with a brown color in volcanic areas, but lighter and sometimes pinkish or yellowish near coral coastline due to the prevailing lime here. Globigerin silt, consisting of microscopic foraminifera, covers the deeper parts of the ocean floor to a depth of almost 4500 m; south of parallel 50 ° S. NS. calcareous foraminiferal deposits disappear and are replaced by microscopic siliceous, from the group of algae, diatoms. With regard to the accumulation of diatom remains on the bottom, the southern Indian Ocean is particularly different from other oceans, where diatoms are found only in places. Red clay occurs at depths greater than 4500 meters; it is red or brown or chocolate colored.

Indian ocean climate fossil fishing

4. Characteristics of waters

Circulation surface waters in the northern part of the Indian Ocean it has a monsoon character: in summer - north-east and east currents, in winter - south-west and west currents. V winter months between 3 ° and 8 ° S NS. the inter-trade (equatorial) countercurrent develops. In the southern part of the Indian Ocean, water circulation forms an anticyclonic cycle, which is formed from warm currents- South Passat in the North, Madagascar and Igolny in the West and cold - the currents of the Western Winds in the South and the West Australian in the East South of 55 ° S. NS. several weak cyclonic water cycles develop, close to the coast of Antarctica with an eastern current.

Indian Ocean Water Beltbetween 10 ° with. NS. and 10 ° NS. NS. called the thermal equator, where the surface water temperature is 28-29 ° C. To the south of this zone, the temperature decreases, reaching −1 ° C off the coast of Antarctica. In January and February, the ice along the coast of this continent melts, huge ice blocks break off the ice sheet of Antarctica and drift towards the open ocean. To the north, the temperature characteristics of the waters are determined by the monsoon air circulation. In summer, temperature anomalies are observed here, when the Somali Current cools the surface water to a temperature of 21-23 ° C. In the eastern part of the ocean on the same geographic latitude the water temperature is 28 ° C, and the highest temperature mark - about 30 ° C - was recorded in the Persian Gulf and the Red Sea. The average salinity of ocean waters is 34.8 ‰ The waters of the Persian Gulf, the Red and Arabian Seas are the most saline: this is explained by intense evaporation with a small amount fresh water brought to the seas by rivers.

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

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

... Bottom sediments of the Indian Ocean and its structure

Bottom sedimentsIndian oceans have the greatest thickness (up to 3-4 km) at the foot of the continental slopes; in the middle of the ocean - a low (about 100 m) thickness and in places of disseminated relief - discontinuous distribution. The most widely represented are foraminifera (on the continental slopes, ridges and at the bottom of most depressions 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 - common 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 ferromanganese nodules, while riftogenic sediments are represented by the products of destruction of deep-seated rocks. Outcrops of bedrock are most often found on continental slopes (sedimentary and metamorphic rocks), mountains (basalts) and mid-oceanic ridges, where, in addition to basalts, serpentinites and peridotites are found, representing little-altered matter of the Earth's upper mantle.

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

... Minerals

The most important minerals in the Indian Ocean are oil and natural gas. Their deposits are located on the shelves of the Persian and Suez Gulfs, in the Bass Strait, on the shelf of the Indian subcontinent. In terms of reserves and production of these minerals, the Indian Ocean ranks first in the world. Ilmenite, monazite, rutile, titanite and zirconium are exploited on the coasts of Mozambique, the islands of Madagascar and Ceylon. Off the coast of India and Australia, there are deposits of barite and phosphorite, and in the shelf zones of Indonesia, Thailand and Malaysia, deposits of cassiterite and ilmenite are being exploited on an industrial scale. On the shelves - oil and gas (especially the Persian Gulf), monazite sands (coastal region of Southwest India), etc .; in reef zones - ores of chromium, iron, manganese, copper, etc .; on the bed there are huge accumulations of ferromanganese nodules.

... ClimateIndian Ocean

Most of Indian Ocean is located in warm climatic zones- equatorial, subequatorial and tropical. Only its southern regions, located in high latitudes, are strongly influenced by Antarctica. The equatorial climate zone of the Indian Ocean is characterized by a constant predominance of humid warm equatorial air. Average monthly temperatures here range from 27 ° to 29 °. The water temperature is slightly higher than the air temperature, which creates favorable conditions for convection and precipitation. Their annual amount is large - up to 3000 mm and more.

... Flora and fauna

The most dangerous mollusks in the world live in the Indian Ocean - the cone snail. Inside the snail there is a rod-like container with poison, which it injects into its prey (fish, worms), its poison is dangerous for humans.

The entire water area of ​​the Indian Ocean lies within the tropical and southern temperate zones. The shallow waters of the tropical belt are characterized by numerous 6- and 8-ray corals, hydrocorals, which, together with calcareous red algae, are capable of creating islands and atolls. The richest fauna of various invertebrates (sponges, worms, crabs, mollusks, sea ​​urchins, officers and sea ​​stars), small but brightly colored coral fish. Most of the coasts are occupied by mangrove thickets, in which the mud jumper stands out - a fish capable of long time exist in the air. The fauna and flora of beaches and rocks drying out at low tide are quantitatively depleted as a result of the oppressive effect of sunlight. In the temperate zone, life on such coastal areas is much richer; here dense thickets of red and brown algae develop (kelp, fucus, microcystis reaching enormous sizes), a variety of invertebrates are abundant. The open spaces of the Indian Ocean, especially the surface layer of the water column (up to 100 m), are also characterized by rich flora. Of the unicellular planktonic algae, several species of anterior and diatom algae prevail, and in the Arabian Sea - blue-green algae, which often cause the so-called water bloom during mass development.

The bulk of ocean animals are crustaceans - copepods (more than 100 species), followed by pterygopods, jellyfish, siphonophores, and other invertebrates. Of unicellular organisms, radiolarians are characteristic; squid are numerous. Of the fish, several species of flying fish are the most abundant, luminous anchovies - myctophids, coriphenes, large and small tuna, sailfish and various sharks, poisonous sea ​​snakes... Sea turtles and large marine mammals (dugongs, toothed and toothless whales, pinnipeds) are widespread. Among the birds, the most common are albatrosses and frigates, as well as several species of penguins that inhabit the coast. South Africa, Antarctica and islands lying in the temperate zone of the ocean.

At night, the surface of the Indian Ocean flickers with lights. The light is produced by small marine plants called dinoflagellates. The glowing areas sometimes have the shape of a wheel with a diameter of 1.5 m.

... Fishing and marine industry

Fishing is poorly developed (catch does not exceed 5% of the world catch) and is limited to the local coastal zone. Near the equator (Japan) is fishing for tuna, and in Antarctic waters - whale fishing. Pearls and mother-of-pearl are mined in Sri Lanka, the Bahrain Islands and the northwest coast of Australia.

The countries of the Indian Ocean also have significant resources of other valuable species mineral raw materials (tin, iron and manganese ores, natural gas, diamonds, phosphorites, etc.).

Bibliography:

1.Encyclopedia "Science" Dorling Kindersley.

.“I get to know the world. Geography "V.A. Markin

3.slovari.yandex.ru ~ TSB books / Indian Ocean /

4.Great Encyclopedic Dictionary of Brockhaus F.A., Efron I.A.

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The Indian Ocean by volume accounts for 20% of the World Ocean. It is bounded by Asia in the north, Africa in the west, and Australia in the east.

In the zone of 35 ° S lat. passes the conditional border with the Southern Ocean.

Description and characteristics

The waters of the Indian Ocean are renowned for their transparency and azure color. The fact is that few freshwater rivers flow into this ocean, these "troublemakers". Therefore, by the way, the water here is much saltier than in others. It is in the Indian Ocean that the saltiest sea in the world is located - the Red Sea.

And the ocean is also rich in minerals. The area near Sri Lanka has been famous for its pearls, diamonds and emeralds since antiquity. And the Persian Gulf is rich in oil and gas.
Area: 76,170 thousand sq. Km

Volume: 282.650 thousand cubic km

Average depth: 3711 m, the greatest depth is the Sunda Trench (7729 m).

Average temperature: 17 ° C, but in the north the waters warm up to 28 ° C.

Currents: two cycles are conditionally distinguished - northern and southern. Both move clockwise and are separated by Equatorial Countercurrent.

Major currents of the Indian Ocean

Warm:

North Passatnoye- originates in Oceania, crosses the ocean from east to west. Beyond the peninsula, Hindustan is divided into two branches. Part flows to the north and gives rise to the Somali current. And the second part of the stream is directed to the south, where it merges with the equatorial countercurrent.

South Passatnoye- begins at the islands of Oceania and moves from east to west up to the island of Madagascar.

Madagascar- branches off from the South Passat and flows parallel to Mozambique from north to south, but slightly east of the Madagascar coast. Average temperature: 26 ° C.

Mozambican Is another branch of the South Tradewind Current. It washes the shores of Africa and merges with the Agulhas in the south. The average temperature is 25 ° C, the speed is 2.8 km / h.

Agulhas, or the current of Cape Agulhas- a narrow and fast current that runs along the east coast of Africa from north to south.

Cold:

Somali- current off the coast of the Somali Peninsula, which changes its direction depending on the monsoon season.

Current of the West Winds encircles Earth in southern latitudes. In the Indian Ocean from it the South Indian, which near the coast of Australia turns into the Western Australian.

Western Australian- moves from south to north along the western coasts of Australia. As it approaches the equator, the water temperature rises from 15 ° C to 26 ° C. Speed: 0.9-0.7 km / h.

The underwater world of the Indian Ocean

Most of the ocean is located in subtropical and tropical zones, and therefore is rich and diverse in species terms.

The coast of the tropics is represented by vast thickets of mangroves, which are home to numerous colonies of crabs and amazing fish - mudskippers. Shallow waters are a great habitat for corals. And in temperate waters grow brown, calcareous and red algae (kelp, macrocysts, fucus).

Invertebrates: numerous molluscs, great amount species of crustaceans, jellyfish. There are many sea snakes, especially venomous ones.

Sharks of the Indian Ocean are a special pride of the water area. This is where the most a large number of shark species: blue, gray, tiger, great white, mako, etc.

Among mammals, dolphins and killer whales are the most numerous. And the southern part of the ocean is a natural habitat for many species of whales and pinnipeds: dugongs, fur seals, and seals. Of the birds, most of all are penguins and albatrosses.

Despite the richness of the Indian Ocean, seafood fishing is underdeveloped here. The catch is only 5% of the world. Tuna, sardines, stingrays, lobsters, lobsters and shrimps are harvested.

Indian Ocean exploration

The coastal countries of the Indian Ocean are the centers of ancient civilizations. That is why the development of the water area began much earlier than, for example, the Atlantic or the Pacific Ocean. Approximately 6 thousand years BC. the waters of the ocean were already plowed by the shuttles and boats of the ancient people. The inhabitants of Mesopotamia sailed to the shores of India and Arabia, the Egyptians carried on a lively maritime trade with the countries of East Africa and the Arabian Peninsula.

Key dates in the history of ocean exploration:

VII century A.D. - Arab sailors make detailed navigation maps coastal zones Indian Ocean, explore the waters off the east coast of Africa, India, the islands of Java, Ceylon, Timor, Maldives.

1405-1433 - Zheng He's seven sea voyages and exploration of trade routes in the northern and eastern parts of the ocean.

1497 - the voyage of Vasco de Gama and the exploration of the eastern coast of Africa.

(Vasco de Gama expedition in 1497)

1642 - two raids of A. Tasman, exploration of the central part of the ocean and the discovery of Australia.

1872-1876 - the first scientific expedition of the British corvette "Challenger", studying the biology of the ocean, relief, currents.

1886-1889 - expedition of Russian researchers led by S. Makarov.

1960-1965 - International Indian Ocean Expedition, established under the auspices of UNESCO. Study of hydrology, hydrochemistry, geology and biology of the ocean.

1990s - today: ocean exploration with satellites, detailed bathymetric atlas.

2014 - after the crash of the Malaysian Boeing, detailed mapping of the southern part of the ocean was carried out, new underwater ridges and volcanoes were discovered.

The ancient name of the ocean is Eastern.

Many species of wildlife in the Indian Ocean have an unusual property - they glow. In particular, this explains the appearance of glowing circles in the ocean.

In the Indian Ocean, ships are periodically found in good condition, however, where the entire crew disappears remains a mystery. Over the past century, this has happened to three ships at once: the Cab Cruiser, the Houston Market and Tarbon tankers.

The Indian Ocean has the smallest number of 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 Arafur 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 - Mascarensky, Crozet, Prince Edward, etc. In tropical latitudes, coral islands rise on volcanic cones - the Maldives, Lakkadiv, Chagos, Cocos, most of the Andaman, etc.

The banks to the northwest. and the East are indigenous, in the north-east. and the West is dominated by alluvial. The coastline is weakly indented, with the exception of the northern part of the Indian Ocean. Almost all seas and large bays (Aden, Oman, Bengal) are located here. In the southern part are the Gulf of Carpentaria, the Great Australian Bight and Spencer, St. Vincent and others.

A narrow (up to 100 km) continental shelf (shelf) stretches along the coast, the outer edge of which is 50-200 m deep (only near Antarctica and northwestern Australia up to 300-500 m). The continental slope is a steep (up to 10-30 °) scarp, in places dissected by the underwater valleys of the Indus, Ganges, and other rivers. m). The Indian Ocean bed is divided by ridges, mountains and ramparts into a number of depressions, the most significant of which are the Arabian Basin, the Western Australian Basin, and the African Antarctic Basin. The bottom of these basins is formed by accumulative and hilly plains; the former are located near the continents in areas with an abundant supply of sedimentary material, the latter - in the central part of the ocean. Among the numerous ridges of the bed, with its straightness and length (about 5,000 km), stands out the meridional East Indian Ridge, which connects in the south with the latitudinal West Australian Ridge; large meridional ridges stretch to the south of the Indian subcontinent and about. Madagascar. Volcanoes (Bardina, Shcherbakova, Lena, and others) are widely represented on the ocean floor, which in places form large massifs (north of Madagascar) and chains (east of the Cocos Islands). Mid-ocean ridges - a mountain system consisting of three branches, diverging 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 Uplift). This system is 400-800 km wide, 2-3 km high 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 are noted up to 400 km. The Australo-Antarctic uplift, in contrast to the middle ridges, is a flatter ridge 1 km high and up to 1500 km wide.

Bottom sediments of the Indian Ocean have the greatest thickness (up to 3-4 km) at the foot of the continental slopes; in the middle of the ocean - a low (about 100 m) thickness and in places of disseminated relief - discontinuous distribution. The most widely represented are foraminifera (on the continental slopes, ridges and at the bottom of most depressions at a depth of up to 4700 m), diatoms (south of 50 ° S), radiolarian (near the equator) and coral sediments. Polygenic sediments - red deep-water clays - are common 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 ferromanganese nodules, while riftogenic sediments are represented by the products of destruction of deep rocks. Outcrops of bedrock are most often found on continental slopes (sedimentary and metamorphic rocks), mountains (basalts) and mid-oceanic ridges, where, in addition to basalts, serpentinites and peridotites are 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 (Sunda arc) and georiftogenals (mid-ocean ridge) - occupy smaller areas and find their continuation in the corresponding structures of Indochina and the rifts of East Africa. These main macrostructures, sharply differing in morphology, structure of the earth's crust, seismic activity, volcanism, are subdivided into smaller structures: plates usually corresponding to the bottom of oceanic basins, blocky ridges, volcanic ridges, in places crowned with coral islands and banks (Chagos, Maldives, etc. .), trench-faults (Chagos, Ob, etc.), often confined to the foot of block ridges (East Indian, West Australian, Maldives, etc.), fault zones, tectonic scarps. Among the structures of the Indian Ocean bed, a special place (for 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 continent of Gondwana.

Mineral resources: on the shelves - oil and gas (especially the Persian Gulf), monazite sands (coastal region of South-West India), etc .; in rift zones - ores of chromium, iron, manganese, copper, etc .; on the bed there are huge accumulations of ferromanganese nodules.

The northern Indian Ocean has a monsoon climate; in the summer, when the region develops over Asia reduced pressure, the south-western currents of equatorial air dominate here, in winter - the north-eastern currents of tropical air. South of 8-10 ° S. NS. atmospheric circulation is much more constant; here in tropical (in summer and in subtropical) latitudes, stable southeastern trade winds prevail, 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 ° С, off the coast of Africa - up to 23 ° С. In the southern part, it decreases in summer to 20-25 ° C at 30 ° S. sh., up to 5-6 ° C at 50 ° S. NS. and below 0 ° C south of 60 ° S. NS. In winter, the air temperature varies from 27.5 ° C at the equator to 20 ° C in the northern part, to 15 ° C at 30 ° S. sh., up to 0-5 ° C at 50 ° S. NS. and below 0 ° C south of 55-60 ° S. NS. At the same time, in the southern subtropical latitudes all year round, the temperature in the West, under the influence of the warm Madagascar Current, is 3-6 ° C higher than in the East, where there is a cold West Australian Current. Cloudiness in the monsoon northern part of the Indian Ocean in winter is 10-30%, in summer up to 60-70%. In the summer, there is also the largest number precipitation. The average annual precipitation in the east of the Arabian Sea and the Bay of Bengal is more than 3000 mm, at 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 cloud cover is 40-50%, south of 40 ° S. NS. - up to 80%. The average annual precipitation in the subtropics is 500 mm in the east, 1000 mm in the west, more than 1000 mm in temperate latitudes; near Antarctica it drops to 250 mm.

The circulation of surface waters in the northern part of the Indian Ocean has a monsoon character: in summer - northeastern and eastern currents, in winter - southwestern and western currents. In the winter months between 3 ° and 8 ° S. NS. the inter-trade (equatorial) countercurrent develops. In the southern part of the Indian Ocean, the circulation of water forms an anticyclonic circulation, which is formed from warm currents - the South Passat in the north, Madagascar and Igolny in the West, and cold - the currents of the Western Winds in the South and the Western Australian in the East to the South of 55 ° S. NS. several weak cyclonic water cycles develop, close to the coast of Antarctica with an eastern current.

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

The surface water temperature reaches a maximum (over 29 ° C) in May in the northern part of the ocean. In the summer of the Northern Hemisphere, it is here 27-28 ° C and only off the coast of Africa decreases to 22-23 ° C under the influence of the emergence of cold waters 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 ° C at 50 ° S. NS. and below -1 ° C south of 55 ° S. NS. In the winter of the Northern Hemisphere, the temperature in the north is 23-25 ​​° С, at the equator it is 28 ° С, at 30 ° S. NS. 21-25 ° C, at 50 ° S NS. from 5 to 9 ° С, south of 60 ° S. NS. 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 is provided by the rivers of South Asia (Ganges, Brahmaputra, etc.) and Africa (Zambezi, Limpopo). The highest salinity is noted 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 southern subtropical latitudes, salinity exceeds 35.5 ‰ (maximum 36.5 ‰ in summer, 36.0 ‰ in winter), and south of 40 ° S. NS. decreases 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 water density is 1024-1024.5. The oxygen content in the surface layer of water increases from 4.5 ml / l in the northern part of the Indian Ocean to 7-8 ml / l south of 50 ° S. NS. At depths of 200-400 m, the oxygen content is significantly lower in absolute value and varies from 0.21-0.76 in the north to 2-4 ml / l in the South, at great 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 places with greenish tints.

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

Ice forms in high latitudes and is carried away by winds and currents together with icebergs in a northern direction (up to 55 ° S lat. In August and up to 65-68 ° S lat. In February).

The deep circulation and vertical structure of the Indian Ocean are formed by waters plunging into 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 Atlantic Ocean(deep waters). Subsurface waters at a depth of 100-150 m to 400-500 m have a temperature of 10-18 ° C, salinity 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 34.68-34.78 ‰; bottom waters below 3500 m in the South have temperatures from -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 belt are characterized by numerous 6- and 8-ray corals, hydrocorals, which, together with calcareous red algae, are capable of creating islands and atolls. Among the powerful coral buildings, there is a rich fauna of various invertebrates (sponges, worms, crabs, molluscs, sea urchins, ophiuras and starfish), small but brightly colored coral fish. Most of the coasts are occupied by mangrove thickets, in which the muddy jumper stands out - a fish that can exist for a long time in the air. The fauna and flora of beaches and rocks drying out at low tide are quantitatively depleted as a result of the oppressive effect of sunlight. In the temperate zone, life on such coastal areas is much richer; here dense thickets of red and brown algae develop (kelp, fucus, macrocystis reaching enormous sizes), a variety of invertebrates are abundant. The open spaces of the Indian Ocean, especially the surface layer of the water column (up to 100 m), are also characterized by rich flora. Of the unicellular planktonic algae, several species of anterior and diatom algae prevail, and in the Arabian Sea - blue-green algae, which often cause the so-called water bloom during mass development.

The bulk of the ocean animals are copepod crustaceans (more than 100 species), followed by pteropods, jellyfish, siphonophores, and other invertebrates. Of unicellular organisms, radiolarians are characteristic; squid are numerous. Of the fish, several species of flying fish are the most abundant, luminous anchovies - myctophids, coriphenes, large and small tuna, sailfish and various sharks, poisonous sea snakes. Sea turtles and large marine mammals (dugongs, toothed and toothless whales, pinnipeds) are widespread. Among the birds, the most common 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.

The Indian Ocean is the very ocean, the depths of which keep many mysteries and secrets. Although Indonesia is washed by two oceans - the Pacific and the Indian, only the second belongs to Bali. It is the Indian Ocean that the surf spots of the island belong to. Since “you need to know your heroes by sight”, we have collected as many more facts about this ocean, some of them are amazing.

General information

The area of ​​the Indian Ocean is about one fifth of the total area of ​​our planet, it washes 4 parts of the world out of 6 possible at once: Australia, Africa, Asia and even Antarctica. The ocean covers 57 groups of islands, 16 countries in Africa and 18 in Asia. It is the youngest and warmest ocean in the world.
During the great discoveries in the 1500s, the Indian Ocean gained status as one of the most important transport routes. First of all, this was due to the desire of Europeans to gain access to India, where jewelry, rice, cotton, chic fabrics and much more were actively purchased. It is the Indian Ocean that connects the largest number of the most important ports in the world. By the way, it is in the Indian Ocean that about 40% of the world's oil is found. Loot comes second natural gas(according to research, reserves amount to about 2.3 trillion cubic meters).

Indian Ocean and surfing

The most popular destinations are:

Indonesia. Surfing began about 80 years ago when American photographer Robert Coke decided to found the Kuta Beach hotel. During the events associated with World War II and Indonesia's struggle for independence, surfing was forgotten. But the insatiable Australians on home spots revived surfing in the 1960s. Countless islands, led by Bali, have made Indonesia the most popular surfing country in Asia. Sumatra (pictured above), Sumbawa, Java, Mentwai, Lombok, Nias, Timor - these are just a few of the places where your vacation will definitely not be "beachy".

Sri Lanka. Surfers sailed here only in 1970. Unfortunately, the happiness did not last long, as the civil war broke out in 1983. After some time, when peace reigned, the waves began to delight surfers again. But in 2006, the island was literally destroyed by a tsunami that killed about 200,000 people. Renovation work continue to this day, but tourism and surfing is returning and gaining momentum. Of course, there are much fewer surf spots than even in Bali - there are about 3 main surf spots here.

India. History is silent about who and when decided to catch their first wave. Although many people associate India only with cows, yoga and endless meditation, surfing has a place to be. There are about 20 surf spots in the south, but getting to the waves is not that easy. Since surfing in India is not yet so popular, and the local population almost, if not at all, speaks English, especially if you are not in Delhi or Mumbai, then get ready for a great language barrier.

Maldives. This place is perfect not only for honeymoon but also for surfing. It was discovered by the Australians in the 70s, crossing the Indian Ocean on a merchant ship towards Male. When one of them was forced to return home, he told his friends about this fabulous place, which served as a real surf boom. Enterprising Australians immediately began to organize trips. From April to October, when the waves will delight even an avid perfectionist, two days on the way will not stop a true surfing fan.

Mauritius. It was opened at the end of the last century. The real thrill is concentrated in the south of the island. What is remarkable, at the same spot at the same time you can meet windsurfers and kitesurfers, and us, ordinary surfers. Therefore, the spots are a bit congested with such a variety. It is also worth noting that Mauritius is included in the segment of luxury resorts, however, like the Maldives, so the option of a hippie vacation or a budget surf trip is unlikely.

Reunion. Small island, a former colony of France. The best spots are located on the west coast of the island. It is very attractive for surfers, even though the probability of a shark attack there is incredibly high (this year has already recorded the 19th case with, alas, a sad outcome).

• The so-called "Milk Sea" was discovered in the Indian Ocean - blue water with a shining whitish tint. The reason for this is the bacterium Vibrio Harveyi, which seeks to get into the most favorable habitat for itself - the intestines of other inhabitants of the ocean. To achieve the goal, this creature takes on just such a "milky" color.
• The blue-ringed octopus is perhaps the most dangerous inhabitant of the Indian Ocean. The size of a palm, an octopus baby is capable of killing up to 10 people with its poison at a time. It should be noted right away that in the water it does not pose a danger, but if it is thrown out of its natural habitat, then this creature shows remarkable aggression. The poison paralyzes the muscular and respiratory systems, as a result of which the person begins to suffocate. It is worth noting that the predominantly habitat of this little hitman is, of course, in Australia.
• The Indian Ocean is rich not only in surfing spots, but also in unsolvable mysteries. It was in these waters that a merchant ship or ship was found more than once without a single damage, but completely empty. Where people disappeared remains a mystery to this day.

And finally, here is a beautiful shot from Padang Padang surf spot, Bali, Indonesia

Position of the Indian Ocean
or where is the Indian Ocean

First of all, the Indian Ocean is the youngest on Earth. It is located mainly in the Southern Hemisphere. Four continents surround it. In the north - the Asian part of Eurasia, in the west Africa, in the east Australia and Antarctica in the south. On the line from Cape Agulhas, the southernmost point of Africa, and along the twentieth meridian to Antarctica, its waves merge with the Atlantic. The Indian Ocean borders the Pacific Ocean in the north from the western coast of the Malacca Peninsula to the northern point of the island of Sumatra and further along the islands of Sumatra, Java, Bali, Sumba, Timor and New Guinea. There was a lot of controversy among geographers about the eastern border. But now everyone seems to have agreed to consider it from Cape York in Australia, through the Torres Strait, New Guinea and further northeast through the Lesser Sunda Islands to the islands of Java, Sumatra and the city of Singapore. Between the islands of New Guinea and Australia, its border runs along the Torres Strait. In the south, the ocean boundary runs from Australia to the west coast of Tasmania and further along the meridian to Antarctica. Thus, when viewed from space, The Indian Ocean is shaped like a triangle…

How large is the Indian Ocean?

The Indian Ocean is the third largest after the Pacific and Atlantic (), its area is 74 917 thousand square kilometers.

Indian Ocean seas

The shores of the bordering continents are poorly indented, therefore there are very few seas in it - in the north it is the Red Sea, the Persian Gulf, the Arabian Sea, the Bay of Bengal and the Andaman Sea, and in the east - the Timor and Arafur seas.

Indian Ocean depth

At the bottom of the Indian Ocean, in its central part, there are several deep-sea basins, separated by underwater ridges and underwater plateaus, and along the Sunda island arc there is deep-sea Sunda Trench... In it, oceanologists found the deepest hole on the ocean floor - 7130 meters from the surface of the water. The average ocean depth is 3897 meters.... The largest islands in the Indian Ocean are Madagascar, Socotra and Sri Lanka. All of them are fragments of ancient continents. In the central part of the ocean there are groups of small volcanic islands, and in tropical latitudes there are quite a few coral islands.

Indian Ocean temperature

The water in the Indian Ocean is warm. In June - August, closer to the equator, its temperature, like in a bath, is 27-28 ° С (and there are places where the thermometer also shows 29 ° С). And only off the coast of Africa, where the cold Somali current passes, the water is colder - 22-23 ° С. But from the equator to the south to Antarctica, the temperature of the water in the ocean changes to 26 and even 28 ° C. From the north it is limited by the shores of the Eurasian continent. From the south - a conditional line connecting the extremities of South Africa and Australia. In the west - Africa.

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But why is the Indian Ocean considered the youngest? The geographical map clearly shows how its basin is surrounded by continental land areas. In the not so distant geological past of our planet, these areas were most likely united into a single continent of Gondwana, which split apart, and parts of it spread in different directions, making room for water.

At the bottom of the Indian Ocean, scientists have discovered several underwater mountain ranges. Moreover The Central Indian Ridge divides the ocean basin into two regions with absolutely different types the earth's crust. Deep cracks adjoin the seamounts. Such a neighborhood inevitably causes frequent earthquakes in these areas, or rather, seaquakes. As a result, tsunamis are born, which bring innumerable troubles to the island and coastal mainland inhabitants.

Submarine volcanoes in these troubled regions eject so much matter from the depths that new islands appear from time to time. Many coral reefs and atolls are found in the local warm waters... Navigating the Indian Ocean is not easy. During stormy periods in some of its regions, huge waves with a height of five-story house! .. Giant catastrophic tsunami waves are not such a rare exotic for the inhabitants of the Indian Ocean basin.