Which ocean is larger: Indian or Atlantic? The history of the discovery of the Indian and Atlantic Oceans. History of Indian Ocean exploration Who studied the Indian Ocean

INTRODUCTION

Indian Ocean

Above the blackness of your depths

Wonderful lights were burning,

And your swell moved heavily,

Exploding fire of silent mines.

She blinded our eyes

And we grew pale in the fast light,

And blue fire networks

Flowed along slow waves.

And again, noisy and deep,

You rebelled and caught fire -

And staggered from star to star

With a great cane, an unsteady foresail.

Behind the shaft the oncoming shaft ran

With the breath of the fiery monsoon,

And the diamond tail of Scorpio

I trembled over your blackness.

Ivan Bunin

Geographical location, history of discovery and development

The nature of the Indian Ocean, to a greater extent than other oceans, has features of tropical exoticism. Most characteristic feature The geographical position of the Indian Ocean is that 84% of its area is located in the Southern Hemisphere. It has no direct connection with the Arctic Ocean.

The Indian Ocean is located between Africa, Asia, Australia and Antarctica, i.e. It is largely limited by land, but at the same time has water boundaries over a large area. The western border of the Indian Ocean is the 20th meridian? e.d. on the stretch between Antarctica (Princess Ranghil Coast) and Cape Agulhas at the southern tip of Africa. In the northeast, the ocean is limited by the northern entrance to the Strait of Malacca, the southwestern and southern shores of the Greater and Lesser Sunda Islands, the southwestern coast of New Guinea to the mouth of the Benebek River, from here by water to Cape York (the northern tip of Australia). In the east, the ocean boundary runs along the coast of Australia to Cape South-East, then crosses the Bass Strait to the north-western tip of Tasmania, then along its western coast to Cape South, from which it runs along the meridian 147? e.d. When distinguishing the Southern Ocean, the southern boundary of the Indian Ocean is drawn along the Antarctic convergence line, which lies between latitudes 48? (at 20? E) and 54? (at 150? East).

If we take the coast of Antarctica as the southern border of the Indian Ocean, then the ocean has an area of ​​76.2 million km 2, a volume of 282.6 million km 3, an average depth of 3711 m, and a greatest depth of 7729 m (the Sunda Trench). The Indian Ocean has approximately the same extent in latitude (11,450 km along the parallel 10? S) and longitude (10,180 km along the meridian 60? E). The southern tropic lies at approximately equal distances from the northern and southern boundaries of the ocean. The Indian Ocean in the northern part is significantly separated by continents and archipelagos. Only in the southern part is it widely connected with the Atlantic and Pacific oceans, which generally ensures good water exchange.

There are many islands in the Indian Ocean. The largest of them - Madagascar, Sri Lanka, Greater Sunda - are of continental origin and are located near the continents. In the open part of the ocean lie the volcanic islands: Comoros (the largest of them is Ngazidja with the active volcano Kargala), Mascarene (the largest island is Reunion), Andaman, Nicobar, Seychelles. Coral islands are especially numerous in the Indian Ocean, most of which are typical atolls. A typical example is the Diego Garcia Atoll. It is an almost continuous ring of land, open only at a slight pull in the northern part.

In addition to atolls, many coral islands in their formation are associated with the development of barrier and coastal coral reefs. Such islands form archipelagos, for example Bahrain and Tanzania, which includes the islands of Zanzibar, Pemba and smaller ones. Many islands of the Indian Ocean, especially coral ones, are characterized by modern coastal erosion, changing their outlines.

The Indian Ocean includes six seas: the Red, Arabian, Andaman and Laccadive seas wash the coast of South-West and South Asia, and the Timor and Arafura seas are located off the northern coast of Australia.

The Indian Ocean seas share many common features. With the exception of the Red Sea, they occupy a marginal position. All seas warm up well and have fairly small seasonal changes in surface water temperature. The most significant feature of these seas is the pronounced monsoons, which determine the main features of the nature of the seas. At the same time, each of them clearly expresses its own individuality, which creates its own “portrait” of the sea.

The history of exploration of the Indian Ocean can 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 3000-1000 BC traveled through the northern part of the Indian Ocean, and ended with the voyage of James Cook, who in 1772-75 penetrated the South to 71° south latitude. The second period was marked by the beginning of deep-sea exploration, 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 complex oceanographic research.

The penetration of Europeans (Portuguese, then the Dutch, French and English) into the Indian Ocean basin dates back to the 16th-17th centuries, and by the mid-19th century, most of its shores and islands were secured by Great Britain, which exported from here the most important raw materials and food products for its economy. . Naval (and later air force) bases were created at all entrances to the Indian Ocean: in the Atlantic Ocean - Simon's Town, in the Pacific Ocean - Singapore, in the Red Sea - Aden, on the approaches to India - Trincomalee. In the northeastern part of the Indian Ocean there were colonies of France, the Netherlands (Netherlands Indies), and Portugal.

After the end of the 2nd World War 1939-1945, the collapse of the colonial system of imperialism made fundamental changes to political map Indian Ocean basin.

They took shape among the ancient peoples who inhabited its shores and beyond (in Southern Europe, North Africa, South-West and East Asia). For trade and military purposes they sailed along various parts ocean.

In the V-IV millennia BC. e. The Sumerians sailed through the Persian Gulf and entered the Arabian Sea. Phoenician sailors six centuries BC. and, having sailed from the Erythraean (Red) Sea, circumnavigated Africa and after 3 years returned home, passing the Pillars of Hercules (Strait of Gibraltar). Mediterranean peoples actively used monsoon winds for their sea voyages in the Indian Ocean. The Greeks and Romans already in the 1st century. n. e. paved a sea route through the Bay of Bengal and established communications with China. Obviously, the ocean waters were explored by sailors from India, Indonesia and others. Arabs in the 7th-8th centuries. We sailed a lot in the Indian Ocean. They summarized the information they received about nature in handwritten books. In 1466-1472. Tver merchant Afanasy Nikitin traveled to India and reached the Indian Ocean (crossed the Arabian Sea). His travel notes “Walking across Three Seas” give a vivid and truthful description of not only his life in this country, but also trade routes there from Eastern Europe. In the XV-XVI centuries. The period of intensive exploration of the ocean by Europeans begins. In 1497-1498 Portuguese along the west coast of Africa. Following the Portuguese, Dutch, French, Spanish, and English sailors rushed into the Indian Ocean, covering its different parts.

The first oceanographic studies, along with geographical descriptions and clarification of the coastline of the Indian Ocean, began to be carried out by sea expeditions from the end of the 18th century.

Thus, during the voyage of D. Cook (1772-1775) it was measured to a depth of 200 m. Oceanographic work in the Indian Ocean was also carried out by the first Russian round-the-world expedition of I. F. Kruzenshtern and Yu. F. Lisyansky (1803-1806). , during expeditions led by O. E. Kotzebue (1815-1818 and 1823-1826). A great contribution to the development of science, including ocean geography, was the work of Charles Darwin.

In the XIX - early XX centuries. wider study of the ocean began. The development of deep-sea research was facilitated by work on laying underwater telegraph cables in the Arabian Sea and the Bay of Bengal (1857-1869). During the round-the-world expedition on the Challenger (1873-1876), comprehensive oceanological research was carried out, including hydrological, geological and biological observations. In 1898-1899 Germany organized a special deep-sea expedition in the Indian Ocean. She is credited with beginning to identify the East Indian and Arabian-Indian ridges. In 1906, measurements by another German ship led to the discovery of the Javanese (Sunda) deep-sea trench.

From the middle of the 20th century. work in the Indian Ocean became more focused. Significant results were brought by oceanographic research carried out by the marine detachments of the diesel-electric ships “Ob” and “Lena” under the program of the International Geophysical Year (1955-1957). The research vessel “Vityaz” (1959-1962, 1965) made a significant contribution to the study of the Indian Ocean.

A major event was the discovery of the West Indian Ridge and its study by US oceanologists (1959-1960). Thanks to the identification of the “missing” southwestern branch of the Mid-Indian Ridge, the existence of a single global system of median ridges of the World Ocean was established. In the period 1960-1965. The International Indian Ocean Expedition (IIOE) was carried out. It was the largest expedition ever to operate in the Indian Ocean. The MIOE program covered almost its entire space with observations. Scientists from about 20 countries took part in it, and the volume turned out to be quite significant. Before this, about 1,500 oceanological stations were made throughout the Indian Ocean, and during the period of MIOE work, only USSR expeditions made observations at more than 2,000 stations over 5 years. After completing research under the MIOE program great importance To clarify the structure and formation of the basins of the Indian Ocean, they carried out deep-sea drilling work from the American vessel Glomar Challenger. As in other oceans, observations are being made in the Indian ocean from autonomous submersible bathyscaphes, which are considered very promising for a detailed study of the ocean depths.

Presentation on the topic "Indian Ocean" on geography for schoolchildren. Consists of nine slides. The presentation examines the Indian Ocean according to the lesson plan: geographical position, history of ocean exploration, features of the nature of the ocean, types of economic activities in the ocean. The project was carried out by Evgenia Yagodorova and Daria Malyutkina.

Excerpts from the presentation:

Lesson plan:

• Geographical position.
• From the history of ocean exploration.
• Features of the nature of the ocean.
• Types of economic activities in the ocean.

Indian Ocean Map

The Indian Ocean has a unique position on the planet: most of it lies in the southern hemisphere. In the north it is limited to Eurasia and has no connection with the Arctic Ocean.

Who discovered and explored the Indian Ocean?

The Arabs were the first to describe ocean navigation routes. Information about the Indian Ocean began to accumulate since the voyages of Vasco da Gama (1497-1499). At the end of the 18th century. The first measurements of the depth of this ocean were carried out by the English navigator J. Cook.

Features of the nature of the ocean

The structure of the bottom topography is complex. Mid-ocean ridges divide the ocean floor into three parts. In the western part there is a ridge connecting south of Africa with the Mid-Atlantic Ridge. The center of the ridge is characterized by deep faults, areas of earthquakes and volcanism on the ocean floor. Fractures in the earth's crust continue in the Red Sea and reach land. The climate is characterized by seasonal monsoon winds in the northern part of the ocean, which is located in the subequatorial zone and is subject to significant influence from land. Monsoons have a huge impact on weather conditions in the northern part of the ocean.

In the south, the ocean experiences the cooling influence of Antarctica; This is where the harshest areas of the ocean lie. The properties of water masses are associated with climate characteristics. The northern part of the ocean warms up well, is deprived of the influx of cold water and is therefore the warmest. The water temperature here is higher (up to +30) than at the same latitudes in other oceans. To the south, the water temperature decreases. The salinity of ocean waters on the surface is generally higher than the salinity of the World Ocean, and in the Red Sea it is especially high (up to 42%). In the northern part of the ocean, the formation of currents is influenced by seasonal changes in winds. Monsoons change the direction of water movement and cause vertical mixing. The current system is being rebuilt. In the south, the currents are part of the general pattern of currents in the World Ocean.

Organic world of the Indian Ocean

Tropical water masses are rich in plankton, which is especially rich in unicellular algae. Among the plankton there are many organisms that glow at night. Variety of fish species: sardinella, mackerel, sharks. Shelf areas and shallow waters near coral reefs are especially rich in life. Turtles and sea snakes live in warm waters. Among the mollusks there are many cuttlefish and squid, and near Antarctica - whales and seals.

Types of economic activities

The ocean shelf is rich in minerals. Huge deposits of oil in the sedimentary rocks at the bottom of the Persian Gulf pose a risk of water pollution. Fishing is also developed. Numerous shipping routes pass through the Indian Ocean. There are especially many sea roads in the northern part of the ocean, where small sailing ships are still used. The direction of their movement is associated with the monsoons.

The project was carried out by Evgenia Yagodorova and Daria Malyutkina.

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

.Fisheries and marine activities

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 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 in Asia belong to the Indian Ocean basin: the Salween, the Irrawaddy and the Ganges with the Brahmaputra, which flow into the Bay of Bengal; Indus, flowing into the Arabian Sea; The Tigris and Euphrates merge slightly above their confluence with the Persian Gulf. From large rivers Africa, which also flows into the Indian Ocean, should be called the Zambezi and Limpopo. Because of them, the water off the ocean coast is cloudy, with a high content of 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 home on coral reefs. The Indian Ocean is home to the famous sea devils, rare whale sharks, largemouths, 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 - of Australia from Antarctica (in the Paleogene, about 50 million years ago).

The Indian Ocean and its shores remain poorly studied. The name of the Indian Ocean appears already at the beginning of the 16th century. by Schöner under the name Oceanus orientalis indicus, in contrast to the Atlantic Ocean, then known as Oceanus occidentalis. Subsequent geographers called the Indian Ocean mostly the Sea of ​​India, some (Varenius) the Australian Ocean, and Fleuriet recommended (in the 18th century) even calling it 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 through the northern part of the Indian Ocean. The first navigation maps were compiled by the ancient Arabs. At the end of the 15th century, the first European, the famous Portuguese Vasco da Gama, circumnavigated 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 English) 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.

History of discoverycan 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 sailors, who 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 the South to 71° S. w.

The second period was marked by the beginning of deep-sea exploration, 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 complex 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, etc. In 1960-65, the Intergovernmental Oceanographic Expedition under UNESCO carried out 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 on Earth (after the Pacific and Atlantic), covering about 20% of its water surface. Almost all of it is located 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, and in the south by the Southern Ocean. The border between the Indian and Atlantic Oceans runs along the 20° meridian of eastern longitude (Meridian of Cape Agulhas), between the Indian and Pacific Oceans, runs along the 147° meridian of east longitude (meridian of the southern cape of Tasmania). The northernmost point of the Indian Ocean is located at approximately 30°N 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 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 least number of seas compared to other oceans. In the northern part there are the largest seas: 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.

In the Indian Ocean are the island states of Madagascar (the fourth largest island in the world), Sri Lanka, Maldives, Mauritius, Comoros, and Seychelles. The ocean washes the following states in the east: 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 with 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 - the Maldives, Laccadives, Chagos, Cocos, most 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, as well as the Australian-Antarctic Rise, converge. The ridges consist of steep mountain ranges, cut by faults perpendicular or oblique to the axes of the chains and divide the basalt ocean floor into 3 segments, and their peaks are, as a rule, extinct volcanoes. The bottom of the Indian Ocean is covered with sediments of the Cretaceous and later periods, the thickness of which varies from several hundred meters to 2-3 km. The deepest of the ocean's many trenches is the Java Trench (4,500 km long and 29 km wide). Rivers flowing into the Indian Ocean carry with them huge quantities of sediment, especially from India, creating high sediment thresholds.

The Indian Ocean coast is replete with cliffs, deltas, atolls, coastal coral reefs and salt marshes covered with mangroves. Some islands - for example, Madagascar, Socotra, the 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 topped 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 undersea earthquake in the Indian Ocean on December 26, 2004 caused a tsunami that was considered 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 in the Indian Ocean, north of the island of Simeulue, 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 height of the waves exceeded 15 meters. The tsunami caused enormous destruction and a huge number of dead people, even in Port Elizabeth, South Africa, 6900 km from the epicenter. According to various estimates, from 225 thousand to 300 thousand people died. The true death toll is unlikely to ever be known, as many people were swept out to sea.

As for 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 shores, with a brown color in volcanic areas, but lighter and sometimes pinkish or yellowish near coral coasts due to the predominant lime. Globigerine mud, composed of microscopic foraminifera, covers the deeper parts of the ocean floor to a depth of almost 4500 m; south of the parallel 50° S. w. calcareous foraminiferal deposits disappear and are replaced by microscopic siliceous, from the group of algae, diatoms. In terms of the accumulation of diatom remains on the bottom, the southern Indian Ocean is particularly different from other oceans, where diatoms are found only locally. Red clay occurs at depths greater than 4500 m; it is red, or brown, or chocolate in color.

Indian Ocean climate fossil fishery

4. Water characteristics

Surface water circulationin the northern part of the Indian Ocean it 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. w. The inter-trade wind (equatorial) countercurrent develops. In the southern part of the Indian Ocean, water circulation forms an anticyclonic circulation, which is formed from warm currents - the Southern Trade Wind in the North, Madagascar and Agulhas in the West and cold currents - the Western Winds in the South and Western Australian in the East. w. Several weak cyclonic water circulations develop, closing off the coast of Antarctica with an eastern current.

Indian Ocean water beltbetween 10 ° With. w. and 10 ° Yu. w. called the thermal equator, where the surface water temperature is 28-29°C. To the south of this zone the temperature drops, reaching about 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 Antarctic ice sheet 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 waters to a temperature of 21-23°C. In the eastern part of the ocean at the same 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, Red and Arabian Seas are the most saline: this is explained by intense evaporation with a small amount of fresh water brought into the seas by rivers.

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 semidiurnal.

Ice forms in 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 sedimentsIndian Ocean have highest power(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 dissected relief is distributed - intermittent distribution. The most widely represented are foraminifera (on continental slopes, ridges and on the bottom of most basins at depths of up to 4700 m), diatoms (south of 50° S), radiolarians (near the equator) and coral sediments. Polygenic sediments - red deep-sea clays - are common south of the equator at a depth of 4.5-6 km or more. Terrigenous sediments - off the coast of continents. Chemogenic sediments are represented mainly by ferromanganese nodules, and riftogenic sediments are represented by products of destruction of deep rocks. Outcrops of bedrock 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, representing the slightly altered material of the Earth's upper mantle, were found.

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 are continued in the corresponding structures of Indochina and the rifts of East Africa. These main macrostructures, which differ sharply in morphology, crustal structure, seismic activity, volcanism, are divided into smaller structures: plates, usually corresponding to the bottom of oceanic basins, block ridges, volcanic ridges, in places topped with coral islands and banks (Chagos, Maldives, etc. .), fault trenches (Chagos, Obi, etc.), often confined to the foot of blocky ridges (East Indian, Western 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 Islands and the continental type of the earth's crust) is occupied by the northern part of the Mascarene Ridge - a structure that is, apparently, part of the ancient continent of Gondwana.

. Minerals

The most important mineral resources of 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, and on the shelf of the Hindustan Peninsula. The Indian Ocean ranks first in the world in terms of reserves and production of these minerals. Ilmenite, monazite, rutile, titanite and zirconium are exploited on the coasts of Mozambique, Madagascar and Ceylon. 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 offshore zones of Indonesia, Thailand and Malaysia. On the shelves - oil and gas (especially the Persian Gulf), monazite sands (coastal region of South-West 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 the Indian Ocean is located in warm climate 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 the constant predominance of moist, 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 or more.

. Flora and fauna

The Indian Ocean is home to the most dangerous mollusks in the world - 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 Indian Ocean lies within the tropical and southern temperate zones. The shallow waters of the tropical zone are characterized by numerous 6- and 8-rayed corals and hydrocorals, which, together with calcareous red algae, can create islands and atolls. Among the powerful coral structures lives a rich fauna of various invertebrates (sponges, worms, crabs, mollusks, sea ​​urchins, brittle stars and starfish), small but brightly colored coral fish. Most of the coasts are occupied by mangroves, in which the mudskipper stands out - a fish that can exist in the air for a long time. The fauna and flora of beaches and rocks that dry out at low tide are quantitatively depleted as a result of the depressing effect of sunlight. In the temperate zone, life on such sections of the coast is much richer; Dense thickets of red and brown algae (kelp, fucus, reaching enormous sizes of microcystis) develop here, and 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 a rich flora. Among unicellular planktonic algae, several species of peredinium and diatom algae predominate, and in the Arabian Sea - blue-green algae, which often cause so-called water blooms when they develop en masse.

The bulk of ocean animals are crustaceans - copepods (more than 100 species), followed by pteropods, jellyfish, siphonophores and other invertebrate animals. The most common unicellular organisms are radiolarians; Squids are numerous. Of the fish, the most abundant are several species of flying fish, luminous anchovies - myctophids, coryphaenas, large and small tuna, sailfish and various sharks, poisonous sea snakes. Distributed sea ​​turtles and large marine mammals (dugongs, toothed and toothless whales, pinnipeds). Among the birds, the most typical are albatrosses and frigatebirds, 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.

At night, the surface of the Indian Ocean shimmers with lights. 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.

. Fisheries and marine activities

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

The Indian Ocean countries 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'm exploring the world. Geography" V.A. Markin

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

4.Large encyclopedic dictionary of Brockhaus F.A., Efron I.A.

Tutoring

Need help studying a topic?

Our specialists will advise or provide tutoring services on topics that interest you.
Submit your application indicating the topic right now to find out about the possibility of obtaining a consultation.

INDIAN OCEAN, the third largest ocean on Earth (after the Pacific and Atlantic), part of the World Ocean. Located between Africa in the northwest, Asia in the north, Australia in the east and Antarctica in the south.

Physiographical sketch

General information

Border of I. o. in the west (with the Atlantic Ocean south of Africa) along the meridian of Cape Agulhas (20° E) to the coast of Antarctica (Donning Maud Land), in the east (with the Pacific Ocean south of Australia) - along the eastern border of the Bass Strait to the island of Tasmania, and then along the meridian 146°55"" E. to Antarctica, in the northeast (with the Pacific Ocean) - between the Andaman Sea and the Strait of Malacca, then along the southwestern coast of the island of Sumatra, the Sunda Strait, the southern coast of the island of Java, the southern borders of the Bali and Savu seas, the northern border of the Arafura sea, the southwestern coast of New Guinea and the western border of the Torres Strait. The southern high-latitude part of the I. region. sometimes referred to as the Southern Ocean, which combines the Antarctic sectors of the Atlantic, Indian and Pacific oceans. However, such geographical nomenclature is not generally accepted, and, as a rule, I. o. considered within its usual boundaries. And about. - the only one of the oceans that is located b. hours in the Southern Hemisphere and is limited in the north by a powerful land mass. Unlike other oceans, its mid-ocean ridges form three branches radiating in different directions from the central part of the ocean.

Area I. o. with seas, bays and straits 76.17 million km 2, water volume 282.65 million km 3, average depth 3711 m (2nd place after the Pacific Ocean); without them - 64.49 million km 2, 255.81 million km 3, 3967 m. The greatest depth in the deep sea Sunda Trench– 7729 m at point 11°10"" S. w. and 114°57"" E. e. The shelf zone of the ocean (conditionally depths up to 200 m) occupies 6.1% of its area, the continental slope (from 200 to 3000 m) 17.1%, the bed (over 3000 m) 76.8%. See map.

Seas

Seas, bays and straits in the waters of the island. almost three times less than in the Atlantic or Pacific Oceans, they are mainly concentrated in its northern part. Seas of the tropical zone: Mediterranean - Red; marginal - Arabian, Laccadive, Andaman, Timor, Arafura; Antarctic zone: marginal - Davis, D'Urville (D'Urville), Cosmonauts, Mawson, Riiser-Larsen, Commonwealth (see separate articles on the seas). Largest bays: Bengal, Persian, Aden, Oman, Great Australian, Carpentaria, Prydz. Straits: Mozambique, Bab el-Mandeb, Bass, Hormuz, Malacca, Polk, Tenth Degree, Great Channel.

Islands

Unlike other oceans, the islands are few in number. The total area is about 2 million km 2. The largest islands of mainland origin are Socotra, Sri Lanka, Madagascar, Tasmania, Sumatra, Java, Timor. Volcanic islands: Reunion, Mauritius, Prince Edward, Crozet, Kerguelen, etc.; coral - Laccadive, Maldives, Amirante, Chagos, Nicobar, b. including Andaman, Seychelles; The coral Comoros, Cocos and other islands rise on volcanic cones.

Shores

And about. It is distinguished by a relatively small indentation of the coastline, with the exception of the northern and northeastern parts, where the bays are located. including seas and major large bays; There are few convenient bays. The coasts of Africa in the western part of the ocean are alluvial, weakly dissected, and often surrounded by coral reefs; in the northwestern part - indigenous. In the north, low, weakly dissected shores with lagoons and sand bars, in places with mangroves, bordered on the landward side by coastal lowlands (Malabar Coast, Coromandel Coast) predominate; abrasion-accumulative (Konkan coast) and deltaic shores are also common. In the east, the shores are indigenous; in Antarctica, they are covered with glaciers descending to the sea, ending in ice cliffs several tens of meters high.

Bottom relief

In the bottom relief of the I. o. Four main elements of geotexture are distinguished: the underwater continental margins (including the shelf and continental slope), transition zones, or island arc zones, the ocean floor and mid-ocean ridges. The area of ​​the underwater continental margins in the I. region. is 17,660 thousand km 2. The underwater margin of Africa is distinguished by a narrow shelf (from 2 to 40 km), its edge is located at a depth of 200–300 m. Only near the southern tip of the continent does the shelf expand significantly and in the area of ​​the Agulhas Plateau extends up to 250 km from the coast. Significant areas of the shelf are occupied by coral structures. The transition from the shelf to the continental slope is expressed by a clear bend in the bottom surface and a rapid increase in its slope to 10–15°. The underwater margin of Asia off the coast of the Arabian Peninsula also has a narrow shelf, gradually expanding on the Malabar coast of Hindustan and off the coast of the Bay of Bengal, while the depth on its outer border increases from 100 to 500 m. The continental slope is clearly visible everywhere along the characteristic slopes of the bottom (height up to 4200 m, Sri Lanka island). The shelf and continental slope in some areas are cut through by several narrow and deep canyons, the most pronounced canyons being underwater continuations of the channels of the Ganges rivers (together with the Brahmaputra River, it annually carries about 1,200 million tons of suspended and traction sediments into the ocean, forming a layer of sediment over 3,500 m thickness). The Indian Ocean margin of Australia is characterized by an extensive shelf, especially in the northern and northwestern parts; in the Gulf of Carpentaria and the Arafura Sea up to 900 km wide; the greatest depth is 500 m. The continental slope to the west of Australia is complicated by underwater ledges and individual underwater plateaus. On the underwater outskirts of Antarctica, there are everywhere traces of the influence of the ice load of the huge glacier covering the continent. The shelf here belongs to a special glacial type. Its outer boundary almost coincides with the 500 m isobath. The shelf width is from 35 to 250 km. The continental slope is complicated by longitudinal and transverse ridges, individual ridges, valleys and deep trenches. At the foot of the continental slope, an accumulative plume composed of terrigenous material brought by glaciers is almost everywhere observed. The largest bottom slopes are observed in the upper part; with increasing depth, the slope gradually flattens out.

Transition zone at the bottom of the I. o. stands out only in the area adjacent to the arc of the Sunda Islands, and represents the southeastern part of the Indonesian transition region. It includes: the Andaman Sea basin, the Sunda Islands island arc and deep-sea trenches. The most morphologically pronounced in this zone is the deep-sea Sunda Trench with a slope steepness of 30° or more. Relatively small deep-sea trenches are identified to the southeast of the island of Timor and east of the Kai Islands, but due to the thick sedimentary layer, their maximum depths are relatively small - 3310 m (Timor Trench) and 3680 m (Kai Trench). The transition zone is extremely seismically active.

Mid-ocean ridges I. o. form three underwater mountain ranges radiating from the area at coordinates 22° S. w. and 68° E. to the northwest, southwest and southeast. Each of the three branches is divided according to morphological characteristics into two independent ridges: the northwestern - into the Middle Aden ridge and Arabian-Indian Ridge, southwestern – on West Indian Ridge and the African-Antarctic Ridge, southeastern - on Central Indian Range And Australasian-Antarctic Rise. That. median ridges separate the bed of the I. o. into three large sectors. The median ridges are vast uplifts, fragmented by transform faults into separate blocks, with a total length of over 16 thousand km, the foothills of which are located at depths of the order of 5000–3500 m. The relative height of the ridges is 4700–2000 m, width 500–800 km, depth of rift valleys up to 2300 m.

In each of the three sectors of the ocean floor, the I.O. characteristic forms of relief are distinguished: basins, individual ridges, plateaus, mountains, troughs, canyons, etc. In the western sector there are the largest basins: Somali (with depths of 3000–5800 m), Mascarene (4500–5300 m), Mozambique (4000–5800 m), 6000 m), Madagascar Basin(4500–6400 m), Agulhas(4000–5000 m); underwater ridges: Mascarene ridge, Madagascar; plateau: Agulhas, Mozambique; individual mountains: Equator, Africana, Vernadsky, Hall, Bardin, Kurchatov; Amirantsky Trench, Mauritius trench; Canyons: Zambezi, Tanganyika and Tagela. In the northeastern sector there are basins: Arabian (4000–5000 m), Central (5000–6000 m), Coconut (5000–6000 m), North Australian (Argo Plain; 5000–5500 m), Western Australian Basin(5000–6500 m), Naturalista (5000–6000 m) and South Australian Basin(5000–5500 m); underwater ridges: Maldives Ridge, East Indian Ridge, Western Australian (Brocken Plateau); Cuvier mountain range; Exmouth plateau; Mill Hill; individual mountains: Moscow State University, Shcherbakova and Afanasy Nikitin; East Indian Trench; Canyons: Indus, Ganges, Seatown and Murray rivers. In the Antarctic sector there are basins: Crozet (4500–5000 m), African-Antarctic Basin (4000–5000 m) and Australian-Antarctic Basin(4000–5000 m, maximum – 6089 m); plateau: Kerguelen, Crozetand Amsterdam; separate mountains: Lena and Ob. The shapes and sizes of the basins are different: from round with a diameter of about 400 km (Comoros) to oblong giants with a length of 5500 km (Central), the degree of their isolation and the bottom topography are different: from flat or gently undulating to hilly and even mountainous.

Geological structure

Feature of I. o. is that its formation occurred both as a result of the split and subsidence of continental massifs, and as a result of the spreading of the bottom and the new formation of oceanic crust within the mid-ocean (spreading) ridges, the system of which was repeatedly rebuilt. The modern mid-ocean ridge system consists of three branches that converge at the Rodriguez Triple Junction. In the northern branch, the Arabian-Indian Ridge continues northwest of the Owen transform fault zone with the Gulf of Aden and Red Sea rift systems and connects with the intracontinental rift systems of East Africa. In the southeastern branch, the Central Indian Ridge and the Australasian-Antarctic Rise are separated by the Amsterdam fault zone, which is connected to the plateau of the same name with the volcanic islands of Amsterdam and Saint-Paul. The Arabian-Indian and Central Indian ridges are slow-spreading (spreading speed is 2–2.5 cm/year), have a well-defined rift valley, and are crossed by numerous transform faults. The wide Australasian-Antarctic Rise does not have a pronounced rift valley; speed spreading it is higher than in other ridges (3.7–7.6 cm/year). To the south of Australia, the uplift is broken up by the Australian-Antarctic fault zone, where the number of transform faults increases and the spreading axis shifts along the faults in a southerly direction. The ridges of the southwestern branch are narrow, with a deep rift valley, densely crossed by transform faults oriented at an angle to the strike of the ridge. They are characterized by a very low spreading rate (about 1.5 cm/year). The West Indian Ridge is separated from the African-Antarctic Ridge by the Prince Edward, Du Toit, Andrew-Bain and Marion fault systems, which shift the ridge axis almost 1000 km to the south. The age of the oceanic crust within the spreading ridges is predominantly Oligocene-Quaternary. The West Indian Ridge, which penetrates like a narrow wedge into the structures of the Central Indian Ridge, is considered the youngest.

Spreading ridges divide the ocean floor into three sectors - African in the west, Asian-Australian in the northeast and Antarctic in the south. Within the sectors there are intra-oceanic uplifts of various natures, represented by “aseismic” ridges, plateaus and islands. Tectonic (block) uplifts have a block structure with varying crustal thickness; often include continental remains. Volcanic uplifts are mainly associated with fault zones. The uplifts are the natural boundaries of deep-sea basins. African sector characterized by the predominance of fragments of continental structures (including microcontinents), within which the thickness of the earth's crust reaches 17–40 km (Agullas and Mozambique plateaus, the Madagascar ridge with the island of Madagascar, individual blocks of the Mascarene ridge with the Bank of the Seychelles Islands and the Saya de Bank -Malya). Volcanic uplifts and structures include the Comoros underwater ridge, crowned by archipelagos of coral and volcanic islands, the Amirante Range, the Reunion Islands, Mauritius, Tromelin, and the Farquhar Massif. In the western part of the African sector I. o. (western part of the Somali Basin, northern part of the Mozambique Basin), adjacent to the eastern underwater margin of Africa, the age of the earth’s crust is predominantly Late Jurassic-Early Cretaceous; in the central part of the sector (Mascarene and Madagascar basins) – Late Cretaceous; in the northeastern part of the sector (eastern part of the Somali Basin) – Paleocene-Eocene. Ancient spreading axes and transform faults intersecting them have been identified in the Somali and Mascarene basins.

For the northwestern (Asian) part Asian-Australian sector characterized by meridional “aseismic” ridges of block structure with increased thickness of the oceanic crust, the formation of which is associated with a system of ancient transform faults. These include the Maldives range, crowned by archipelagos of coral islands - Laccadive, Maldives and Chagos; so-called ridge 79°, Lanka ridge with Mount Afanasia Nikitin, East Indian (so-called ridge 90°), Investigator, etc. Thick (8–10 km) sediments of the Indus, Ganges and Brahmaputra rivers in the northern part of the I.O. partially overlapped by ridges extending in this direction, as well as by the structures of the transition zone between the Indian Ocean and the southeastern edge of Asia. The Murray Ridge in the northern part of the Arabian Basin, bounding the Oman Basin from the south, is a continuation of folded land structures; falls within the Owen fault zone. South of the equator, a sublatitudinal zone of intraplate deformations up to 1000 km wide has been identified, which is characterized by high seismicity. It stretches in the Central and Cocos Basins from the Maldives Ridge to the Sunda Trench. The Arabian Basin is underlain by crust of Paleocene-Eocene age, the Central Basin by crust of Late Cretaceous - Eocene age; the crust is youngest in the southern part of the basins. In the Cocos Basin, the crust ranges in age from Late Cretaceous in the south to Eocene in the north; in its northwestern part, an ancient spreading axis was established, which separated the Indian and Australian lithospheric plates until the mid-Eocene. The Coconut Rise, a latitudinal uplift with numerous seamounts and islands (including the Cocos Islands) rising above it, and the Rhu Rise, adjacent to the Sunda Trench, separate the southeastern (Australian) part of the Asian-Australian sector. Western Australian Basin (Wharton) in the central part of the Asian-Australian sector of the I.O. it is underlain by Late Cretaceous crust in the north-west and Late Jurassic in the east. Submerged continental blocks (marginal plateaus of Exmouth, Cuvier, Zenith, Naturalista) divide the eastern part of the basin into separate depressions - Cuvier (north of the Cuvier plateau), Perth (north of the Naturalista plateau). The crust of the North Australian Basin (Argo) is the oldest in the south (Late Jurassic); becomes younger in a northern direction (until the Early Cretaceous). The age of the crust of the South Australian Basin is Late Cretaceous – Eocene. The Brocken Plateau (West Australian Ridge) is an intra-oceanic rise with increased (from 12 to 20 km, according to various sources) crustal thickness.

IN Antarctic sector And about. There are mainly volcanic intra-oceanic uplifts with increased thickness of the earth's crust: the Kerguelen, Crozet (Del Caño) and Conrad plateaus. Within the largest Kerguelen plateau, presumably founded on an ancient transform fault, the thickness of the earth’s crust (according to some data, Early Cretaceous age) reaches 23 km. Rising above the plateau, the Kerguelen Islands are a multiphase volcanoplutonic structure (composed of alkali basalts and syenites of Neogene age). On Heard Island there are Neogene-Quaternary alkaline volcanics. In the western part of the sector there are the Conrad plateau with the volcanic mountains Ob and Lena, as well as the Crozet plateau with a group of volcanic islands Marion, Prince Edward, Crozet, composed of Quaternary basalts and intrusive massifs of syenites and monzonites. The age of the earth's crust within the African-Antarctic, Australian-Antarctic basins and the Crozet Basin of the Late Cretaceous is Eocene.

For I. o. in general, the predominance of passive margins is characteristic (the continental margins of Africa, the Arabian and Indian peninsulas, Australia, Antarctica). The active margin is observed in the northeastern part of the ocean (the Sunda transition zone between the Indian Ocean and Southeast Asia), where subduction(underthrust) of the ocean lithosphere under the Sunda island arc. A subduction zone of limited extent, the Makran subduction zone, was identified in the northwestern part of the I.O. Along the Agulhas I. plateau. borders the African continent along a transform fault.

Formation of the I. o. began in the middle of the Mesozoic during the split of the Gondwanan part (see. Gondwana) supercontinent Pangea, which was preceded by continental rifting during the Late Triassic - Early Cretaceous. The formation of the first sections of oceanic crust as a result of the separation of continental plates began in the Late Jurassic in the Somali (about 155 million years ago) and North Australian (151 million years ago) basins. In the Late Cretaceous, the northern part of the Mozambique Basin experienced the spreading of the bottom and the new formation of oceanic crust (140–127 million years ago). The separation of Australia from Hindustan and Antarctica, accompanied by the opening of basins with oceanic crust, began in the Early Cretaceous (about 134 million years ago and about 125 million years ago, respectively). Thus, in the Early Cretaceous (about 120 million years ago), narrow oceanic basins arose, cutting into the supercontinent and dividing it into separate blocks. In the middle of the Cretaceous period (about 100 million years ago), the ocean floor began to grow intensively between Hindustan and Antarctica, which led to the drift of Hindustan in a northerly direction. In the time interval of 120–85 million years ago, the spreading axes that existed north and west of Australia, off the coast of Antarctica and in the Mozambique Channel, died out. In the Late Cretaceous (90–85 million years ago), a split began between Hindustan with the Mascarene-Seychelles block and Madagascar, which was accompanied by bottom spreading in the Mascarene, Madagascar and Crozet basins, as well as the formation of the Australasian-Antarctic Rise. At the Cretaceous-Paleogene boundary, Hindustan separated from the Mascarene-Seychelles block; the Arabian-Indian spreading ridge arose; the extinction of spreading axes occurred in the Mascarene and Madagascar basins. In the middle of the Eocene, the Indian lithospheric plate merged with the Australian one; the still developing system of mid-ocean ridges was formed. Close to the modern appearance of the I. o. acquired in the early-mid Miocene. In the middle of the Miocene (about 15 million years ago), during the split of the Arabian and African plates, new formation of oceanic crust began in the Gulf of Aden and the Red Sea.

Modern tectonic movements in the I. o. noted in mid-ocean ridges (associated with shallow-focus earthquakes), as well as in individual transform faults. The area of ​​intense seismicity is the Sunda island arc, where deep-focus earthquakes are caused by the presence of a seismofocal zone plunging in the northeast direction. During earthquakes on the northeastern outskirts of the I. o. tsunami formation is possible.

Bottom sediments

The rate of sedimentation in the I. region. generally lower than in the Atlantic and Pacific oceans. The thickness of modern bottom sediments varies from a discontinuous distribution at mid-ocean ridges to several hundred meters in deep-sea basins and 5000–8000 m at the foot of continental slopes. The most widespread are calcareous (mainly foraminiferal-coccolithic) silts, covering over 50% of the ocean floor area (on continental slopes, ridges and the bottom of basins at depths of up to 4700 m) in warm oceanic areas from 20° N. w. up to 40° south w. with high biological productivity of water. Polygenic sediments – red deep ocean clays– occupy 25% of the bottom area at depths of over 4700 m in the eastern and southeastern parts of the ocean from 10° N. w. up to 40° south w. and in areas of the bottom remote from islands and continents; in the tropical region, red clays alternate with siliceous radiolarian silts covering the bottom of deep-sea basins of the equatorial belt. In deep-sea sediments, they are present in the form of inclusions. ferromanganese nodules. Siliceous, predominantly diatomaceous, silts occupy about 20% of the bottom of the I. lake; distributed at great depths south of 50° S. w. The accumulation of terrigenous sediments (pebbles, gravel, sands, silts, clays) occurs mainly along the coasts of continents and within their underwater margins in areas of river and iceberg runoff and significant wind removal of material. The sediments covering the African shelf are mainly of shell and coral origin; phosphorite nodules are widely developed in the southern part. Along the northwestern periphery of the Indian Ocean, as well as in the Andaman Basin and the Sunda Trench, bottom sediments are represented mainly by deposits of turbidity (turbide) flows - turbidites with the participation of products of volcanic activity, underwater landslides, landslides, etc. Sediments of coral reefs are widespread in the western part of the island. from 20° south w. up to 15° N. latitude, and in the Red Sea - up to 30° N. w. Outcrops discovered in the Red Sea rift valley metalliferous brines with temperatures up to 70 °C and salinity up to 300‰. IN metalliferous sediments, formed from these brines, have a high content of non-ferrous and rare metals. On continental slopes, seamounts, and mid-ocean ridges, there are outcrops of bedrock (basalts, serpentinites, peridotites). Bottom sediments around Antarctica are classified as a special type of iceberg sediment. They are characterized by a predominance of a variety of clastic material, ranging from large boulders to silts and fine silts.

Climate

Unlike the Atlantic and Pacific oceans, which have a meridional extension from the shores of Antarctica to the Arctic Circle and communicate with the Arctic Ocean, the I. o. in the northern tropical region it is bordered by a land mass, which largely determines the characteristics of its climate. The uneven heating of land and ocean leads to seasonal changes in extensive minimums and maximums of atmospheric pressure and to seasonal shifts of the tropical atmospheric front, which in the winter of the Northern Hemisphere retreats south to almost 10° S. sh., and in summer it is located in the foothills of southern Asia. As a result, over the northern part of the I. region. The climate is dominated by a monsoon climate, which is primarily characterized by changes in wind direction throughout the year. The winter monsoon with relatively weak (3–4 m/s) and stable northeast winds operates from November to March. During this period, north of 10° S. w. Calms are common. The summer monsoon with southwest winds occurs from May to September. In the northern tropical region and in the equatorial zone of the ocean, the average wind speed reaches 8–9 m/s, often reaching storm force. In April and October, a restructuring of the pressure field usually occurs, and during these months the wind situation is unstable. Against the background of the prevailing monsoon atmospheric circulation over the northern part of the I. region. isolated manifestations of cyclonic activity are possible. During the winter monsoon, there are known cases of cyclones developing over the Arabian Sea, and during the summer monsoon - over the waters of the Arabian Sea and the Bay of Bengal. Strong cyclones in these areas sometimes form during periods of monsoon change.

Approximately 30° S. w. in the central part of I. o. there is a stable area of ​​high pressure, the so-called. South Indian High. This stationary anticyclone is component southern subtropical high pressure area - persists all year round. The pressure at its center varies from 1024 hPa in July to 1020 hPa in January. Under the influence of this anticyclone in the latitudinal band between 10 and 30° S. w. Steady southeast trade winds blow throughout the year.

South of 40° S. w. atmospheric pressure in all seasons decreases uniformly from 1018–1016 hPa on the southern periphery of the South Indian High to 988 hPa at 60° S. w. Under the influence of the meridional pressure gradient in the lower layer of the atmosphere, a stable zap is maintained. air transfer. The highest average wind speed (up to 15 m/s) is observed in the middle of winter in the Southern Hemisphere. For higher southern latitudes I. o. Throughout almost the entire year, stormy conditions are characteristic, in which winds with speeds of more than 15 m/s, causing waves over 5 m in height, have a frequency of 30%. South of 60° S. w. Along the coast of Antarctica, easterly winds and two or three cyclones per year are usually observed, most often in July–August.

In July, the highest air temperatures in the surface layer of the atmosphere are observed at the top of the Persian Gulf (up to 34 °C), the lowest are off the coast of Antarctica (–20 °C), over the Arabian Sea and the Bay of Bengal on average 26–28 °C. Above the water area of ​​the I. o. air temperature almost everywhere changes in accordance with geographic latitude. In the southern part of I. o. it gradually decreases from north to south by about 1 °C every 150 km. In January, the highest air temperatures (26–28 °C) are observed in the equatorial belt, near the northern coasts of the Arabian Sea and the Bay of Bengal - about 20 °C. In the southern part of the ocean, the temperature gradually decreases from 26 °C in the Southern Tropics to 0 °C and slightly lower at the latitude of the Antarctic Circle. The amplitude of annual fluctuations in air temperature over b. parts of the water area of ​​the I. o. on average less than 10 °C and only off the coast of Antarctica increases to 16 °C.

The greatest amount of precipitation per year falls in the Bay of Bengal (over 5500 mm) and off the eastern coast of the island of Madagascar (over 3500 mm). The northern coastal part of the Arabian Sea receives the least amount of rainfall (100–200 mm per year).

North-eastern regions of I. o. located in seismically active areas. The eastern coast of Africa and the island of Madagascar, the shores of the Arabian Peninsula and the Hindustan Peninsula, almost all island archipelagos of volcanic origin, the western shores of Australia, especially the arc of the Sunda Islands, have in the past been repeatedly exposed to tsunami waves of varying strength, up to catastrophic ones. In 1883, after the explosion of the Krakatau volcano in the Jakarta area, a tsunami with a wave height of over 30 m was recorded; in 2004, a tsunami caused by an earthquake in the area of ​​​​the island of Sumatra had catastrophic consequences.

Hydrological regime

Seasonality in changes in hydrological characteristics (primarily temperature and currents) is most clearly manifested in the northern part of the ocean. The summer hydrological season here corresponds to the duration of the southwest monsoon (May - September), the winter - to the northeast monsoon (November - March). A feature of the seasonal variability of the hydrological regime is that the restructuring of hydrological fields is somewhat delayed relative to the meteorological fields.

Water temperature. In the winter of the Northern Hemisphere, the highest water temperatures in the surface layer are observed in the equatorial zone - from 27 °C off the coast of Africa to 29 °C or more east of the Maldives. In the northern regions of the Arabian Sea and Bay of Bengal, the water temperature is about 25 °C. In the southern part of I. o. Everywhere there is a zonal distribution of temperature, which gradually decreases from 27–28 °C to 20° S. w. to negative values ​​at the edge of the drifting ice, located approximately 65–67° S. w. In the summer season, the highest water temperatures in the surface layer are observed in the Persian Gulf (up to 34 °C), in the north-west of the Arabian Sea (up to 30 °C), in the eastern part of the equatorial zone (up to 29 °C). In the coastal areas of the Somali and Arabian peninsulas, abnormally low values ​​(sometimes less than 20 °C) are observed at this time of year, which is the result of the rise to the surface of cooled deep waters in the Somali Current system. In the southern part of I. o. The distribution of water temperature throughout the year remains zonal in nature, with the difference that its negative values ​​in the winter of the Southern Hemisphere are found much further north, already around 58–60° S. w. The amplitude of annual fluctuations in water temperature in the surface layer is small and averages 2–5 °C; only in the area of ​​the Somali coast and in the Gulf of Oman in the Arabian Sea does it exceed 7 °C. The water temperature quickly decreases vertically: at a depth of 250 m it almost everywhere drops below 15 °C, deeper than 1000 m – below 5 °C. At a depth of 2000 m, temperatures above 3 °C are observed only in the northern part of the Arabian Sea, in the central regions - about 2.5 °C, in the southern part it decreases from 2 °C to 50° S. w. to 0 °C off the coast of Antarctica. Temperatures in the deepest (over 5000 m) basins range from 1.25 °C to 0 °C.

Salinity of surface waters I. o. is determined by the balance between the amount of evaporation and the total amount of precipitation and river flow for each region. The absolute maximum salinity (over 40‰) is observed in the Red Sea and the Persian Gulf, in the Arabian Sea everywhere, with the exception of a small area in the southeastern part, salinity is above 35.5‰, in the band 20–40° S. w. – more than 35‰. The area of ​​low salinity is located in the Bay of Bengal and in the area adjacent to the Sunda Islands arc, where fresh river flow is high and precipitation is greatest. In the northern part of the Bay of Bengal, salinity is 30–31‰ in February, and 20‰ in August. An extensive tongue of water with salinity up to 34.5‰ at 10° south. w. extends from the island of Java to 75° east. e. In Antarctic waters, salinity is everywhere below the average oceanic value: from 33.5‰ in February to 34.0‰ in August, its changes are determined by slight salinization during formation sea ​​ice and appropriate desalination during the melting period. Seasonal changes in salinity are noticeable only in the upper, 250-meter layer. With increasing depth, not only seasonal fluctuations fade, but also spatial variability of salinity; deeper than 1000 m it fluctuates between 35–34.5‰.

Density The highest density of water in I. o. observed in the Suez and Persian Gulfs (up to 1030 kg/m 3) and in cold Antarctic waters (1027 kg/m 3), average - in the warmest and saltiest waters in the northwest (1024–1024.5 kg/m 3) , the smallest is in the most desalinated waters in the northeastern part of the ocean and in the Bay of Bengal (1018–1022 kg/m3). With depth, mainly due to a decrease in water temperature, its density increases, sharply increasing in the so-called. jump layer, which is most noticeably expressed in the equatorial zone of the ocean.

Ice regime. Severity of climate in the southern part of the island. is such that the process of sea ice formation (at air temperatures below –7 °C) can occur almost all year round. The ice cover reaches its greatest development in September–October, when the width of the drifting ice belt reaches 550 km, and its smallest development in January–February. Ice cover is characterized by great seasonal variability and its formation occurs very quickly. The ice edge moves north at a speed of 5–7 km/day, and retreats just as quickly (up to 9 km/day) to the south during the melting period. Fast ice is established annually, reaches an average width of 25–40 km and almost completely melts by February. Drifting ice off the coast of the continent moves under the influence of katabatic winds in a general direction to the west and northwest. Near the northern edge, the ice drifts eastward. A characteristic feature of the Antarctic ice sheet is the large number of icebergs breaking off from the outlet and shelf glaciers of Antarctica. Table-shaped icebergs are especially large, which can reach a gigantic length of several tens of meters, rising 40–50 m above the water. Their number quickly decreases as they move away from the shores of the mainland. The average lifespan of large icebergs is 6 years.

Currents I. Circulation of surface waters in the northern part of the I. region. is formed under the influence of monsoon winds and therefore changes significantly from the summer to the winter season. In February from 8° N. w. off the Nicobar Islands to 2° N. w. off the coast of Africa there is a surface winter Monsoon current with speeds of 50–80 cm/s; with a core running approximately 18° S. sh., in the same direction the South Trade Wind Current is spreading, with an average speed on the surface of about 30 cm/s. Connecting off the coast of Africa, the waters of these two streams give rise to the Intertrade Countercurrent, which carries its waters to the east with velocities in the core of about 25 cm/s. Along the North African coast, with a general direction to the south, the waters of the Somali Current move, partially turning into the Intertrade Countercurrent, and to the south - the Mozambique and Cape Agulhas Currents, moving south at speeds of about 50 cm/s. Part of the South Passat Current east coast the island of Madagascar turns south along it (Madagascar Current). South of 40° S. w. the entire ocean area is crossed from west to east by the longest and most powerful stream in the World Ocean Western Wind Currents(Antarctic Circumpolar Current). The velocities in its rods reach 50 cm/s, and the flow rate is about 150 million m 3 /s. At 100–110° E. from it a stream branches off, heading north and giving rise to the Western Australian Current. In August, the Somali Current follows a general direction to the northeast and, at a speed of up to 150 cm/s, pushes water into the northern part of the Arabian Sea, from where the Monsoon Current, skirting the western and southern shores of the Hindustan Peninsula and the island of Sri Lanka, carries water to the shores of the island Sumatra turns south and merges with the waters of the South Trade Wind Current. Thus, in the northern part of I. o. an extensive clockwise gyre is created, consisting of the Monsoon, South Trade Wind and Somali currents. In the southern part of the ocean, the pattern of currents changes little from February to August. Off the coast of Antarctica, in a narrow coastal strip, a current caused by katabatic winds and directed from east to west is observed all year round.

Water masses. In the vertical structure of water masses I. o. According to hydrological characteristics and depth, surface, intermediate, deep and bottom waters are distinguished. Surface waters are distributed in a relatively thin surface layer and, on average, occupy the upper 200–300 m. From north to south, water masses are distinguished in this layer: Persian and Arabian in the Arabian Sea, Bengal and South Bengal in the Bay of Bengal; further, south of the equator - Equatorial, Tropical, Subtropical, Subantarctic and Antarctic. As the depth increases, the differences between neighboring water masses decrease and their number decreases accordingly. Thus, in intermediate waters, the lower limit of which reaches 2000 m in temperate and low latitudes and up to 1000 m in high latitudes, the Persian and Red Sea in the Arabian Sea, the Bengal in the Bay of Bengal, the Subantarctic and Antarctic intermediate water masses are distinguished. Deep waters are represented by the North Indian, Atlantic (in the western part of the ocean), Central Indian (in the eastern part) and Circumpolar Antarctic water masses. Bottom waters everywhere, except the Bay of Bengal, are represented by one Antarctic bottom water mass, filling all deep-sea basins. The upper limit of bottom water is located on average at a horizon of 2500 m off the coast of Antarctica, where it is formed, up to 4000 m in the central regions of the ocean and rises to almost 3000 m north of the equator.

Tides and waves e. The greatest distribution on the shores of the I. o. have semidiurnal and irregular semidiurnal tides. Semidiurnal tides are observed on the African coast south of the equator, in the Red Sea, off the northwestern coast of the Persian Gulf, in the Bay of Bengal, and off the northwestern coast of Australia. Irregular semidiurnal tides - off the Somali Peninsula, in the Gulf of Aden, off the coast of the Arabian Sea, in the Persian Gulf, off the southwestern coast of the Sunda island arc. Diurnal and irregular tides occur off the western and southern coasts of Australia. The highest tides are off the northwestern coast of Australia (up to 11.4 m), in the mouth of the Indus (8.4 m), in the mouth of the Ganges (5.9 m), off the coast of the Mozambique Strait (5.2 m) ; in the open ocean, the magnitude of the tides varies from 0.4 m near the Maldives to 2.0 m in the southeastern part of the island. Waves reach their greatest strength in temperate latitudes in the zone of action of westerly winds, where the frequency of waves over 6 m high per year is 17%. Waves with a height of 15 m and a length of 250 m were recorded near the Kerguelen Island, and 11 m and 400 m, respectively, off the coast of Australia.

Flora and fauna

The main part of the water area of ​​the I. o. located within the tropical and southern temperate zones. Absence in I. o. northern high-latitude region and the action of monsoons lead to two differently directed processes that determine the characteristics of the local flora and fauna. The first factor complicates deep-sea convection, which negatively affects the renewal of deep waters of the northern part of the ocean and the increase in oxygen deficiency in them, which is especially pronounced in the Red Sea intermediate water mass, which leads to a depletion of species composition and reduces the total biomass of zooplankton in the intermediate layers. When oxygen-poor waters in the Arabian Sea reach the shelf, local death occurs (death of hundreds of thousands of tons of fish). At the same time, the second factor (monsoons) creates favorable conditions for high biological productivity in coastal areas. Under the influence of the summer monsoon, water is driven along the Somali and Arabian coasts, which causes powerful upwelling, bringing water rich in nutritious salts to the surface. The winter monsoon, although to a lesser extent, leads to seasonal upwelling with similar consequences off the western coast of the Indian subcontinent.

The coastal zone of the ocean has the greatest species diversity. The shallow waters of the tropical zone are characterized by numerous 6- and 8-rayed madrepore corals and hydrocorals that, together with red algae, can create underwater reefs and atolls. Among the powerful coral structures lives a rich fauna of various invertebrates (sponges, worms, crabs, mollusks, sea urchins, brittle stars and starfish), small but brightly colored coral reef fish. Most of the coasts are occupied by mangroves. At the same time, the fauna and flora of beaches and rocks that dry out at low tide are quantitatively depleted due to the depressing effect of sunlight. In the temperate zone, life on such sections of the coast is much richer; Dense thickets of red and brown algae (kelp, fucus, macrocystis) develop here, and a variety of invertebrates are abundant. According to L.A. Zenkevich(1965), St. 99% of all species of bottom and benthic animals living in the ocean live in the littoral and sublittoral zones.

The open spaces of the lake, especially the surface layer, are also characterized by rich flora. The food chain in the ocean begins with microscopic single-celled organisms plant organisms– phytoplankton, which inhabits mainly the uppermost (about 100-meter) layer of ocean waters. Among them, several species of peridinian and diatom algae predominate, and in the Arabian Sea - cyanobacteria (blue-green algae), which often cause the so-called mass development. water bloom. In the northern part of I. o. There are three areas of highest phytoplankton production: the Arabian Sea, Bay of Bengal and Andaman Sea. The greatest production is observed off the coast of the Arabian Peninsula, where the number of phytoplankton sometimes exceeds 1 million cells/l (cells per liter). Its high concentrations are also observed in the subantarctic and Antarctic zones, where during the spring flowering period there are up to 300,000 cells/l. The lowest phytoplankton production (less than 100 cells/l) is observed in the central part of the ocean between parallels 18 and 38° S. w.

Zooplankton inhabits almost the entire thickness of oceanic waters, but its quantity quickly decreases with increasing depth and decreases by 2–3 orders of magnitude towards the bottom layers. Food for b. Some of the zooplankton, especially those living in the upper layers, are phytoplankton, therefore the patterns of spatial distribution of phyto- and zooplankton are largely similar. The highest levels of zooplankton biomass (from 100 to 200 mg/m3) are observed in the Arabian and Andaman seas, the Bengal, Aden and Persian Gulfs. The main biomass of ocean animals consists of copepod crustaceans (more than 100 species), with slightly less pteropods, jellyfish, siphonophores and other invertebrate animals. Radiolarians are typical of unicellular organisms. In the Antarctic region I. o. characterized by a huge number of euphausian crustaceans of several species, collectively called “krill”. Euphausiids create the main food supply for the largest animals on Earth - baleen whales. In addition, fish, seals, cephalopods, penguins and other bird species feed on krill.

Organisms that move freely in the marine environment (nekton) are presented in the I. o. mainly fish, cephalopods, and cetaceans. From cephalopods in I. o. Cuttlefish, numerous squid and octopuses are common. Of the fish, the most abundant are several species of flying fish, luminous anchovies (coryphaenas), sardinella, sardine, mackerel, nototheniids, groupers, several types of tuna, blue marlin, grenadier, sharks, and rays. Warm waters are home to sea turtles and poisonous sea snakes. The fauna of aquatic mammals is represented by various cetaceans. The most common baleen whales are: blue whale, sei whale, fin whale, humpback whale, and Australian (Cape) whale. Toothed whales are represented by sperm whales and several species of dolphins (including killer whales). In the coastal waters of the southern part of the ocean, pinnipeds are widespread: the Weddell seal, the crabeater seal, seals - Australian, Tasmanian, Kerguelen and South African, Australian sea lion, leopard seal, etc. Among the birds, the most typical are the wandering albatross, petrels, great frigatebird, phaetons , cormorants, gannets, skuas, terns, gulls. South of 35° S. sh., on the coasts of South Africa, Antarctica and islands - numerous. colonies of several penguin species.

In 1938 in I. o. a unique biological phenomenon was discovered - a living lobe-finned fish Latimeria chalumnae, considered extinct tens of millions of years ago. "Fossil" coelacanth lives at a depth of over 200 m in two places - near the Comoros Islands and in the waters of the Indonesian archipelago.

History of the study

The northern coastal areas, especially the Red Sea and deeply incised bays, began to be used by humans for navigation and fishing already in the era of ancient civilizations, several thousand years BC. e. 600 BC e. Phoenician sailors, in the service of the Egyptian pharaoh Necho II, circumnavigated Africa. In 325–324 BC. e. Alexander the Great's comrade Nearchus, commanding a fleet, sailed from India to Mesopotamia and compiled the first descriptions of the coastline from the mouth of the Indus River to the top of the Persian Gulf. In the 8th–9th centuries. The Arabian Sea was intensively explored by Arab navigators, who created the first sailing directions and navigational guides for this area. In the 1st half. 15th century Chinese navigators under the leadership of Admiral Zheng He made a series of voyages along the Asian coast to the west, reaching the coast of Africa. In 1497–99 the Portuguese Vasco da Gama paved the sea route for Europeans to India and the countries of Southeast Asia. A few years later, the Portuguese discovered the island of Madagascar, the Amirante, Comoros, Mascarene and Seychelles islands. Following the Portuguese in I. o. The Dutch, French, Spanish and English entered. The name "Indian Ocean" first appeared on European maps in 1555. In 1772–75 J. Cook penetrated into I. o. to 71° 10" S and carried out the first deep-sea measurements. Oceanographic research on the island began with systematic measurements of water temperature during the circumnavigation of the Russian ships "Rurik" (1815–18) and "Enterprise" (1823–26) In 1831–36, an English expedition took place on the ship Beagle, on which Charles Darwin carried out geological and biological work. Complex oceanographic measurements in the I.O. were carried out during the English expedition on the ship Challenger in 1873–74. Oceanographic work in the northern part of the island was carried out by S. O. Makarov on the ship “Vityaz” in 1886. In the first half of the 20th century, oceanographic observations began to be carried out regularly, and by the 1950s they were carried out on almost 1,500 deep-sea oceanographic stations. In 1935, P. G. Schott’s monograph “Geography of the Indian and Pacific Oceans” was published - the first major publication that summarized the results of all previous studies in this region. In 1959, the Russian oceanographer A. M. Muromtsev published a fundamental work - “Main Features Hydrology of the Indian Ocean". In 1960–65, the Scientific Committee on Oceanography of UNESCO conducted the International Indian Ocean Expedition (IIOE), the largest of those previously operating in the Indian Ocean. Scientists from more than 20 countries (USSR, Australia, Great Britain, India, Indonesia, Pakistan, Portugal, USA, France, Germany, Japan, etc.) took part in the MIOE program. During the MIOE, major geographical discoveries were made: the underwater West Indian and East Indian ridges were discovered, tectonic fault zones - Owen, Mozambique, Tasmanian, Diamantina, etc., underwater mountains - Ob, Lena, Afanasia Nikitina, Bardina, Zenit, Equator and etc., deep-sea trenches - Ob, Chagos, Vima, Vityaz, etc. In the history of the study of I. o. The results of research carried out in 1959–77 AD are particularly highlighted. the ship "Vityaz" (10 voyages) and dozens of other Soviet expeditions on ships of the Hydrometeorological Service and the State Fisheries Committee. From the beginning 1980s Ocean research was carried out within the framework of 20 international projects. Research on I. o. has become especially intensified. during the International Ocean Circulation Experiment (WOCE). After its successful completion in the end. 1990s the volume of modern oceanographic information on the I.O. doubled in size.

Modern research on I. o. are carried out within the framework of international programs and projects, such as the International Geosphere-Biosphere Program (since 1986, 77 countries participate), including the projects Dynamics of Global Ocean Ecosystems (GLOBES, 1995–2010), Global Flows of Matter in the Ocean ( JGOFS, 1988-2003), Land-Ocean Interactions in the Coastal Zone (LOICZ), Integrated Marine Biogeochemistry and Ecosystem Research (IMBER), Land-Ocean Interactions in the Coastal Zone (LOICZ, 1993-2015), Study of Ocean Surface Interactions with the lower atmosphere (SOLAS, 2004–15, ongoing); “World Climate Research Program” (WCRP, since 1980, 50 countries participate), the main marine part of which is the program “Climate and Ocean: Instability, Predictability and Variability” (CLIVAR, since 1995), the basis of which was the results of TOGA and WOCE; International study of biogeochemical cycles and large-scale distribution of trace elements and their isotopes in the marine environment (GEOTRACES, 2006–15, ongoing) and many others. etc. The Global Ocean Observing System (GOOS) is being developed. Since 2005, the international ARGO program has been operating, in which observations are carried out by autonomous sounding instruments throughout the World Ocean (including the Arctic Ocean), and the results are transmitted through artificial Earth satellites to data centers. From the end 2015 begins the 2nd International Indian Ocean Expedition, designed for 5 years of research with the participation of many countries.

Economic use

Coastal zone I. o. has an exceptionally high population density. There are over 35 states on the coasts and islands, home to about 2.5 billion people. (over 30% of the world's population). The bulk of the coastal population is concentrated in South Asia (more than 10 cities with a population of over 1 million people). In most countries in the region, there are acute problems of finding living space, creating jobs, providing food, clothing and housing, and medical care.

The use of the ocean, like other seas and oceans, is carried out in several main areas: transport, fishing, extraction of mineral resources, and recreation.

Transport

Role of acting in maritime transport increased significantly with the creation of the Suez Canal (1869), which opened a short sea route for communication with states washed by the waters of the Atlantic Ocean. is an area of ​​transit and export of all kinds of raw materials, in which almost all major seaports are of international importance. In the northeastern part of the ocean (in the Malacca and Sunda Straits) there are routes for ships traveling to the Pacific Ocean and back. The main export item to the USA, Japan and Western European countries is crude oil from the Persian Gulf region. In addition, products are exported Agriculture– natural rubber, cotton, coffee, tea, tobacco, fruits, nuts, rice, wool; wood; miner raw materials - coal, iron ore, nickel, manganese, antimony, bauxite, etc.; machinery, equipment, tools and hardware, chemical and pharmaceutical products, textiles, processed gemstones and jewelry. To the share of I. o. accounts for about 10% of the cargo turnover of world shipping, in con. 20th century About 0.5 billion tons of cargo were transported through its waters per year (according to IOC data). According to these indicators, it ranks 3rd after the Atlantic and Pacific oceans, inferior to them in terms of shipping intensity and total volume of cargo transportation, but surpassing all other sea transport communications in terms of oil transportation volume. The main transport routes along the Indian Ocean are directed to the Suez Canal, the Strait of Malacca, the southern tips of Africa and Australia, and along the northern coast. Shipping is most intense in the northern regions, although limited by storm conditions during the summer monsoon, and less intense in the central and southern regions. The growth of oil production in the Persian Gulf countries, Australia, Indonesia, and other places contributed to the construction and modernization of oil ports and the emergence of the I.O. giant tankers. The most developed transport routes for the transportation of oil, gas and petroleum products: Persian Gulf - Red Sea - Suez Canal - Atlantic Ocean; Persian Gulf – Strait of Malacca – Pacific Ocean; Persian Gulf - southern tip of Africa - Atlantic Ocean (especially before the reconstruction of the Suez Canal, 1981); Persian Gulf - Australian coast (port of Fremantle). Mineral and agricultural raw materials, textiles, precious stones, jewelry, equipment, computer technology from India, Indonesia, Thailand. From Australia, coal, gold, aluminum, alumina, iron ore, diamonds, uranium ores and concentrates, manganese, lead, zinc are transported; wool, wheat, meat products, as well as internal combustion engines, passenger cars, electrical products, river vessels, glass products, rolled steel, etc. Oncoming flows are dominated by industrial goods, cars, electronic equipment, etc. An important place in the transport use of i. transport of passengers.

Fishing

Compared to other oceans, the I. o. has relatively low biological productivity; production of fish and other seafood accounts for 5–7% of the total world catch. Fishing and non-fishery fishing is concentrated mainly in the northern part of the ocean, and in the west it is twice as much as in the eastern part. The largest volumes of bioproduct production are observed in the Arabian Sea off the western coast of India and off the coast of Pakistan. Shrimp are harvested in the Persian and Bengal Bays, and lobsters are harvested off the east coast of Africa and on tropical islands. In open ocean areas in the tropical zone, tuna fishing is widely developed, carried out by countries with well-developed fishing fleets. In the Antarctic region, nototheniids, icefish and krill are caught.

Mineral resources

Almost throughout the entire shelf area of ​​the I. o. deposits of oil and natural combustible gas or oil and gas shows have been identified. The most industrially important are the actively developed oil and gas fields in the Persian Gulf ( Persian Gulf oil and gas basin), Suez (Gulf of Suez oil and gas basin), Cambay ( Cambay oil and gas basin), Bengali ( Bengal oil and gas basin); off the northern coast of the island of Sumatra (North Sumatra oil and gas basin), in the Timor Sea, off the northwestern coast of Australia (Carnarvon oil and gas basin), in Bass Strait (Gippsland oil and gas basin). Gas deposits have been explored in the Andaman Sea, oil and gas bearing areas in the Red Sea, Gulf of Aden, and along the coast of Africa. Coastal-sea placers of heavy sands are developed off the coast of the island of Mozambique, along the southwestern and northeastern coasts of India, off the northeastern coast of the island of Sri Lanka, along the southwestern coast of Australia (mining ilmenite, rutile, monazite and zircon); in the coastal areas of Indonesia, Malaysia, Thailand (cassiterite mining). On the shelves I. o. Industrial accumulations of phosphorites were discovered. Large fields of ferromanganese nodules, a promising source of Mn, Ni, Cu, and Co, have been established on the ocean floor. In the Red Sea, identified metal-bearing brines and sediments are potential sources of production of iron, manganese, copper, zinc, nickel, etc.; There are deposits of rock salt. In the coastal zone of the I. o. sand is mined for construction and glass production, gravel, and limestone.

Recreational resources

From the 2nd half. 20th century The use of ocean recreational resources is of great importance for the economies of coastal countries. Old resorts are being developed and new ones are being built on the coasts of continents and on numerous tropical islands in the ocean. The most visited resorts are in Thailand (Phuket island, etc.) - over 13 million people. per year (together with the coast and islands of the Gulf of Thailand of the Pacific Ocean), in Egypt [Hurghada, Sharm el-Sheikh (Sharm el-Sheikh), etc.] - over 7 million people, in Indonesia (the islands of Bali, Bintan , Kalimantan, Sumatra, Java, etc.) - over 5 million people, in India (Goa, etc.), in Jordan (Aqaba), in Israel (Eilat), in the Maldives, in Sri Lanka, in the Seychelles islands, on the islands of Mauritius, Madagascar, South Africa, etc.

Port cities

On the banks of I. o. specialized oil loading ports are located: Ras Tanura (Saudi Arabia), Kharq (Iran), Al-Shuaiba (Kuwait). The largest ports of the island: Port Elizabeth, Durban (South Africa), Mombasa (Kenya), Dar es Salaam (Tanzania), Mogadishu (Somalia), Aden (Yemen), Kuwait City (Kuwait), Karachi (Pakistan) ), Mumbai, Chennai, Kolkata, Kandla (India), Chittagong (Bangladesh), Colombo (Sri Lanka), Yangon (Myanmar), Fremantle, Adelaide and Melbourne (Australia).