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

.Climate of the Indian Ocean

.vegetable and animal world

.Fishing and marine industry

Introduction

Indian Ocean - the youngest and warmest among the world's oceans. Most of it is in the southern hemisphere, and in the north it goes far into the mainland, which is why ancient people considered it just a big 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: the Salween, the Irrawaddy and the Ganges with the Brahmaputra, which flow into the Bay of Bengal; the Indus, which flows into the Arabian Sea; Tigris and Euphrates, merging a little above the confluence with the Persian Gulf. Of the major rivers of Africa, which also flow into the Indian Ocean, the Zambezi and Limpopo should be mentioned. Because of them, the water off the coast of the ocean is cloudy, with a high content sedimentary rocks- sand, silt and clay. But the open waters of the ocean are amazingly clear. The tropical islands of the Indian Ocean are famous 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, etc.

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 a 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 explored. The name of the Indian Ocean is found already at the beginning of the 16th century. Schöner 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 by the sea of ​​India, some (Varenius) by the Australian Ocean, and Fleurie recommended (in the 18th 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 Phoenicia traveled across the northern part of the Indian Ocean. The first navigation 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 and entered the waters of the Indian Ocean. By the 16th-17th centuries, Europeans (the 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 coasts 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 globe. It began with the first voyages of Indian, Egyptian and Phoenician navigators, who, in 3000-1000 BC. traveled through the northern part of the Indian Ocean, and ended with the voyage of J. Cook, who in 1772-75 penetrated south to 71 ° S. sh.

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

The third period is characterized by complex oceanographic research. Until 1960 they were carried out on separate ships. The largest work was 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, etc. In 1960-65, the Intergovernmental Oceanographic Expedition under UNESCO conducted an international Indian Ocean expedition, which collected new valuable data on hydrology, hydrochemistry, meteorology , geology, geophysics and biology of the Indian Ocean.

. General information

Indian Ocean- the third largest ocean of the Earth (after the Pacific and Atlantic), covering about 20% of its water surface. Almost all of it is in the southern hemisphere. Its area is 74917 thousand km ² ; average volume of water - 291945 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 of east longitude. (meridian of the Cape of Needles), between the Indian and Pacific Ocean passes along the 147 ° meridian of east longitude (meridian of the southern cape of the island of Tasmania). 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.

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

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

The Indian Ocean has the fewest seas compared to other oceans. In the northern part are located 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 Arafura and Timor seas.

In the Indian Ocean, there are the island states of Madagascar (the fourth largest island in the world), Sri Lanka, the Maldives, Mauritius, the Comoros, and the Seychelles. The ocean washes in the east such states: Australia, Indonesia; in the northeast: 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 - Mascarene, Crozet, Prince Edward, etc. In tropical latitudes, coral islands rise on volcanic cones - Maldives, Laccadive, Chagos, Cocos, most of the Andaman, etc.

. Bottom relief

The ocean floor is a system of mid-ocean ridges and basins. In the region of Rodrigues Island (Mascarene Archipelago) there is a so-called triple junction, where the Central Indian and West Indian ridges converge, as well as the Australo-Antarctic Rise. The ridges consist of steep mountain ranges cut by normal or oblique faults with respect to the axes of the chains 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 deposits of the Cretaceous and later periods, the thickness of which varies from several hundred meters to 2-3 km. The deepest of the numerous trenches of the ocean is the 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 the territory of India, creating high alluvial rapids.

The coast of the Indian Ocean is replete with cliffs, deltas, atolls, coastal coral reefs and salt marshes overgrown with mangroves. Some islands - for example, Madagascar, Socotra, Maldives - are fragments of ancient continents. Numerous islands and archipelagos of volcanic origin are scattered in the open part of the Indian Ocean. 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, also has a volcanic origin.

An underwater earthquake in the Indian Ocean on December 26, 2004 triggered a tsunami, which was recognized as the deadliest natural disaster in 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 on record.

The epicenter of the earthquake was located in the Indian Ocean, north of the island of Simeulue, located near 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 height of the waves exceeded 15 meters. The tsunami caused massive destruction and a huge number of dead people, even in Port Elizabeth, in South Africa, 6900 km from the epicenter. Died, according to various estimates, from 225 thousand to 300 thousand people. true number the dead are unlikely to ever be known, as many people were carried away by the water into the sea.

With regard to the properties of the bottom soil, then, like in other oceans, sediments on the bottom of the Indian Ocean can be divided into three classes: coastal sediments, organic silt (globigerine, radiolar or diatom) and special clay of great depths, the so-called red clay. Coastal sediments are sand, located mostly on coastal shallows to a depth of 200 meters, green or blue silt near rocky coasts, brown in volcanic areas, but lighter and sometimes pinkish or yellowish near coral coasts due to the lime prevailing here. Globigerin silt, consisting of microscopic foraminifers, covers the deeper parts of the ocean floor almost to a depth of 4500 m; south of parallel 50°S sh. 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 part of the Indian Ocean is especially different from other oceans, where diatoms are found only in places. Red clay occurs at depths greater than 4500 m; it has the color red, or brown, or chocolate.

indian ocean climate fossil fishery

4. Characteristics of waters

Circulation surface water in the northern part of the Indian Ocean it has a monsoonal character: in summer - northeast and east currents, in winter - southwest and west currents. AT 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- South Tradewind in the North, Madagascar and Needle in the West and cold - currents of the West Winds in the South and 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.

Belt of the Indian Oceanbetween 10 ° with. sh. and 10 ° Yu. sh. called the thermal equator, where the surface water temperature is 28-29°C. To the south of this zone, the temperature drops, reaching ?1°C off the coast of Antarctica. In January and February, the ice along the coast of this continent melts, huge blocks of ice break off from 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 surface waters to a temperature of 21-23°C. In the eastern part of the ocean on the same geographical 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‰ fresh water carried to the seas by rivers.

The tides in the Indian Ocean, as a rule, are small (off 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).

. Bottom sediments of the Indian Ocean and its structure

Bottom sedimentsthe Indian Ocean have the greatest thickness (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 - 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 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 bed of the Indian Ocean 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 Range - a structure that, apparently, is part of the ancient mainland of Gondwana.

. 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. In terms of reserves and production of these minerals, the Indian Ocean ranks first in the world. On the coasts of Mozambique, the islands of Madagascar and Ceylon, 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. On the shelves - oil and gas (especially the Persian Gulf), monazite sands (the coastal region of Southwestern India), etc.; in reef zones - ores of chromium, iron, manganese, copper, etc.; on the bed - 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 at 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 range here 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 - cone snails. Inside the snail there is a rod-like container with poison, which it injects into its prey (fish, worms), its poison is also 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 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, mollusks, sea ​​urchins, ophiurs and sea ​​stars), small but brightly colored coral fish. Most of the coasts are occupied by mangroves, in which the mudskipper stands out - a fish capable of long time exist in the air. 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 huge size of microcystis) 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, often causing the so-called water bloom during mass development.

The bulk of the ocean's animals are copepods (more than 100 species), 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 tuna, 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 frigatebirds, 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 shimmers with lights. Light is produced by small marine plants called dinoflagellates. Luminous areas sometimes have the shape of a wheel with a diameter of 1.5 m.

. Fishing and marine industry

Fishing is underdeveloped (the 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. In Sri Lanka, on the Bahrain Islands and on the northwestern coast of Australia, pearls and mother-of-pearl are mined.

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 know the world. Geography” V.A. Markin

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

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

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The Indian Ocean is 20% of the world's oceans by volume. It is bounded by Asia to the north, Africa to the west, and Australia to the east.

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

Description and characteristics

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

And the ocean is rich in minerals. The region near Sri Lanka has been famous for its pearls, diamonds and emeralds since ancient times. 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 the Equatorial Countercurrent.

Major currents of the Indian Ocean

Warm:

Northern Tradewind- 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 flow goes south, where it merges with the equatorial countercurrent.

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

Madagascar- branches off from the South Tradewind and flows parallel to the 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 coast 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 course of Cape Agulhas- a narrow and fast current that runs along the east coast of Africa from north to south.

Cold:

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

The course of the West winds encircles Earth in southern latitudes. In the Indian Ocean, from it is the South Indian Ocean, which, near the coast of Australia, passes into the West Australian.

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

Underwater world of the Indian Ocean

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

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

Invertebrates: numerous mollusks, great amount species of crustaceans, jellyfish. Lots of sea snakes, especially venomous ones.

Sharks of the Indian Ocean are a special pride of the water area. Here dwells the most a large number of types of sharks: blue, gray, tiger, great white, mako, etc.

Of the mammals, dolphins and killer whales are the most common. And the southern part of the ocean is the natural habitat of many species of whales and pinnipeds: dugongs, seals, seals. Most of the birds are penguins and albatrosses.

Despite the richness of the Indian Ocean, the seafood industry is poorly developed here. The catch is only 5% of the world. They harvest tuna, sardines, rays, lobsters, lobsters and shrimp.

Indian Ocean exploration

The coastal countries of the Indian Ocean are the centers of the most 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 shuttles and boats of 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:

7th century AD - Arab sailors make detailed navigational charts coastal zones Indian Ocean, explore the water area near the eastern 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 - Vasco de Gama sails and explores the east coast of Africa.

(Expedition of Vasco de Gama in 1497)

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

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

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

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

1990s - present: studying the ocean with the help of satellites, compiling a 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 luminous 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 ship "Cabin Cruiser", the tankers "Houston Market" and "Tarbon".

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 develops over Asia reduced pressure, 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 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, 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 - the northeast and east currents, in winter - the 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.

The tides in the Indian Ocean, as a rule, are small (off 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 Atlantic Ocean(deep waters). Subsurface waters have a temperature of 10-18°C at a depth of 100-150 m to 400-500 m, 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 tuna, 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 the islands that lie in the temperate zone of the ocean.

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

General information

The area of ​​the Indian Ocean is approximately one-fifth of the total area of ​​​​our planet, washes at once 4 parts of the world out of 6 possible: 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 period of great discoveries in the 1500s, the Indian Ocean gained status as one of the most important transportation 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 located. Second place is loot natural gas(according to studies, the reserves are 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 the Second World War and the Indonesian struggle for independence, surfing was forgotten. But insatiable for home spots, Australians revived surfing in the 1960s. The countless number of islands led by Bali have made Indonesia the most popular country in Asia for surfing. Sumatra (pictured above), Sumbawa, Java, Mentwai, Lombok, Nias, Timor - this is just a small part of the places where your vacation will definitely not be “beach”.

Sri Lanka. Surfers sailed here only in 1970. Unfortunately, happiness did not last long, as a civil war broke out in 1983. After some time, when peace reigned, the waves again began to delight surfers. But in 2006, the island was literally destroyed by a tsunami that claimed the lives of about 200,000 people. Restoration work last until now, 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 associate India only with cows, yoga and endless meditations, surfing has a place to be. There are about 20 surf spots in the south, but getting to the waves is not so easy. Since surfing in India is not yet so popular, and the local population speaks little or no 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 a honeymoon, but also for surfing. The Australians discovered this in the 70s, crossing the Indian Ocean on a merchant ship towards Male. When one of them was forced to return to his homeland, 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 road will not stop a real surfer.

Mauritius. It was opened at the end of the last century. The real buzz is concentrated in the south of the island. Remarkably, on the same spot at the same time you can meet windsurfers, 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 despite the fact that the probability of a shark attack there is incredibly high (this year the 19th case with, alas, a sad outcome has already been recorded).

• In the Indian Ocean, the so-called “Milky Sea” is found - blue water with a radiant 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, a baby octopus 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 predominant habitat of this little killer, of course, is in Australia.
• The Indian Ocean is rich not only in surf spots, but also in unsolvable mysteries. It was in these waters that a merchant ship or a ship was found more than once without a single damage, but completely empty. Where the people disappeared remains a mystery to this day.

And finally, here is a beautiful shot from the surf spot Padang Padang, 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. Along 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 Malay 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 count 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 western coast of Tasmania and further along the meridian to Antarctica. Thus, when viewed from space, The Indian Ocean is shaped like a triangle…

What is the area of ​​the Indian Ocean?

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

Seas of the Indian Ocean

The shores of the bordering continents are slightly 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 Arafura Seas.

Depth of the Indian Ocean

At the bottom of the Indian Ocean, in its central part, there are several deep-water basins separated by underwater ridges and underwater plateaus, and along the Sunda island arc there is deep water Sunda Trench. In it, oceanologists found the deepest hole on the ocean floor - 7130 meters from the surface of the water. The average depth of the ocean 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.

Temperature of the Indian Ocean

The water in the Indian Ocean is warm. In June - August, closer to the equator, its temperature, as in a bath, is 27-28 ° C (and there are places where the thermometer shows 29 ° C). And only off the coast of Africa, where the cold Somali current passes, the water is colder - 22-23 ° С. But from the equator south to the Antarctic, 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 tips of South Africa and Australia. West is 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 landmasses. In the not so distant geological past of our planet, these areas were most likely connected into a single mainland Gondwana, which split, and its parts spread out in different directions, making room for water.

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

Submarine volcanoes in these restless regions eject so much material from the bowels that new islands appear from time to time. Many coral reefs and atolls are found in the local warm waters. Driving ships in 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.