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

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

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

Etymology

The ancient Greeks called the western part of the ocean known to them with the adjacent seas and bays the Erythraean Sea (ancient Greek Ἐρυθρά θάλασσα - Red, and in old Russian sources the Red Sea). Gradually, this name began to be attributed only to the nearest sea, and the ocean was named after India, the country most famous at that time for its wealth on the shores of the ocean. So Alexander the Great in the 4th century BC. e. calls it Indicon pelagos (ancient Greek Ἰνδικόν πέλαγος) - “Indian Sea”. Among the Arabs, it is known as Bar el-Hind (modern Arabic: al-muhit al-hindiy) - “Indian Ocean”. Since the 16th century, the name Oceanus Indicus (Latin Oceanus Indicus) - Indian Ocean, introduced by the Roman scientist Pliny the Elder back in the 1st century, has been established.

Physiographic characteristics

General information

The Indian Ocean is mainly located south of the Tropic of Cancer between Eurasia to the north, Africa to the west, Australia to the east and Antarctica to the south. The border with the Atlantic Ocean runs along the meridian of Cape Agulhas (20° E to the coast of Antarctica (Donning Maud Land)). The border with the Pacific Ocean runs: south of Australia - along the eastern border of the Bass Strait to the island of Tasmania, then along the meridian 146°55’E. to Antarctica; north of Australia- between the Andaman Sea and the Strait of Malacca, further along the southwestern coast of the island of Sumatra, the Sunda Strait, south coast 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. Sometimes the southern part of the ocean, with the northern border from 35° south. w. (based on the circulation of water and atmosphere) up to 60° south. w. (by the nature of the bottom topography) are classified as the Southern Ocean, which is not officially distinguished.

Seas, bays, islands

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

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

History of the formation of the Indian Ocean

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

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

Geological structure and bottom topography of the Indian Ocean

Mid-ocean ridges

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

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

African segment of the ocean

The underwater margin of Africa has a narrow shelf and a clearly defined continental slope with marginal plateaus and a continental foot. In the south, the African continent forms protrusions extended to the south: the Agulhas Bank, Mozambique and Madagascar ranges, composed of continental-type earth crust. The continental foot forms an sloping plain that expands to the south along the coasts of Somalia and Kenya, which continues into the Mozambique Channel and borders Madagascar on the east. The Mascarene Range runs along the east of the sector, in the northern part of which are the Seychelles Islands.

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

Indo-Australian ocean segment

The Indo-Australian segment occupies half the area of ​​the Indian Ocean. In the west, in the meridional direction, the Maldives ridge runs, on the summit surface of which the islands of Laccadive, Maldives and Chagos are located. The ridge is composed of continental-type crust. Along the coasts of Arabia and Hindustan stretch a very narrow shelf, a narrow and steep continental slope and a very wide continental foot, mainly formed by two giant fans of turbidity flows of the Indus and Ganges rivers. These two rivers each carry 400 million tons of debris into the ocean. The Indus Cone extends far into the Arabian Basin. And only the southern part of this basin is occupied by a flat asbyssal plain with individual seamounts.

Almost exactly 90°E. The blocky oceanic East Indian Ridge stretches for 4000 km from north to south. Between the Maldives and East Indian ridges is the Central Basin, the largest basin in the Indian Ocean. Its northern part is occupied by the Bengal fan (from the Ganges River), to southern border which is adjacent to the abyssal plain. In the central part of the basin there is a small ridge called Lanka and the Afanasy Nikitin underwater mountain. To the east of the East Indian Ridge are the Cocos and Western Australian basins, separated by the blocky sublatitudinal oriented Cocos uplift with the Cocos and Christmas islands. In the northern part of the Cocos Basin there is a flat abyssal plain. From the south it is bounded by the Western Australian Uplift, which abruptly breaks off to the south and gently plunges under the bottom of the basin to the north. From the south, the Western Australian Rise is limited by a steep scarp associated with the Diamantina fault zone. The ralom zone combines deep and narrow grabens (the most significant are Ob and Diamatina) and numerous narrow horsts.

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

The underwater edge of the Australian mainland

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

Antarctic ocean segment

The Antarctic segment is limited by the West Indian and Central Indian ridges, and from the south by the shores of Antarctica. Under the influence of tectonic and glaciological factors, the Antarctic shelf has been deepened. The wide continental slope is cut through by large and wide canyons, through which supercooled waters flow from the shelf into the abyssal depressions. The continental foot of Antarctica is distinguished by a wide and significant (up to 1.5 km) thickness of loose sediments.

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

Bottom sediments

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

Climate

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

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

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

Hydrological regime of the Indian Ocean

Surface water circulation

In the northern part of the ocean there is a seasonal change in currents caused by the monsoon circulation. In winter, the South-West Monsoon Current is established, starting in the Bay of Bengal. South of 10° N. w. this current turns into the Western Current, crossing the ocean from the Nicobar Islands to the coast East Africa. Then it branches: one branch goes north to the Red Sea, the other goes south to 10° S. w. and, turning east, gives rise to the Equatorial Countercurrent. The latter crosses the ocean and, off the coast of Sumatra, is again divided into a part that goes into the Andaman Sea and the main branch, which goes to the Pacific Ocean between the Lesser Sunda Islands and Australia. In summer, the southeast monsoon ensures that the entire mass of surface water moves eastward, and the Equatorial Countercurrent disappears. The summer monsoon current begins off the coast of Africa with the powerful Somali Current, to which in the area Gulf of Aden the current from the Red Sea joins. In the Bay of Bengal, the summer monsoon current is divided into northern and southern, which flows into the South Trade Wind Current.

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

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

Temperature, water salinity

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

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

Water masses

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

Flora and fauna

The flora and fauna of the Indian Ocean are incredibly diverse. The tropical region is distinguished by the richness of plankton. The unicellular alga Trichodesmium (cyanobacteria) is especially abundant, due to which the surface layer of water becomes very cloudy and changes its color. The plankton of the Indian Ocean is distinguished by a large number glowing at night organisms: peridines, some types of jellyfish, ctenophores, tunicates. Brightly colored siphonophores are abundant, including poisonous physalia. In temperate and arctic waters, the main representatives of plankton are copepods, euphausids and diatoms. The most numerous fish of the Indian Ocean are coryphens, tunas, nototheniids and various sharks. Among reptiles there are several species of giant sea turtles, sea snakes, and among mammals there are cetaceans (toothless and blue whales, sperm whales, dolphins), seals, and elephant seals. Most cetaceans live in temperate and subpolar regions, where intensive mixing of waters creates favorable conditions for the development of planktonic organisms. Birds are represented by albatross and frigatebirds, as well as several species of penguins, inhabiting the coasts of South Africa, Antarctica and the islands lying in the temperate zone of the ocean.

Vegetable world The Indian Ocean is represented by brown (sargassum, turbinaria) and green algae (caulerpa). The calcareous algae lithothamnia and halimeda also develop luxuriantly, which participate together with corals in the construction of reef structures. In the process of activity of reef-forming organisms, coral platforms are created, sometimes reaching a width of several kilometers. Typical for the coastal zone of the Indian Ocean is the phytocenosis formed by mangroves. Such thickets are especially characteristic of river mouths and occupy significant areas in Southeast Africa, western Madagascar, Southeast Asia and other areas. For temperate and Antarctic waters, the most characteristic are red and brown algae, mainly from the fucus and kelp groups, porphyry, and gelidium. Giant macrocystis are found in the polar regions of the southern hemisphere.

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

Ecological problems

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

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

Indian Ocean states

States along the Indian Ocean borders (clockwise):

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

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

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

History of the study

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

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

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

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

Economic significance

Fisheries and marine industries

The importance of the Indian Ocean for global fisheries is small: catches here account for only 5% of the total. The main commercial fish in the local waters are tuna, sardines, anchovies, several species of sharks, barracudas and stingrays; Shrimp, lobster and lobster are also caught here. Until recently, whaling, which was intense in the southern regions of the ocean, is quickly curtailed due to the almost complete extermination of some species of whales. Pearls and mother-of-pearl are mined on the northwestern coast of Australia, Sri Lanka and the Bahrain Islands.

Transport routes

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

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. Ilmenite, monazite, rutile, titanite and zirconium are exploited on the coasts of India, Mozambique, Tanzania, South Africa, the islands of Madagascar and Sri Lanka. 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.

Recreational resources

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

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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 is the Asian part of Eurasia, in the west is Africa, in the east is Australia and Antarctica in the south. Along a 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 on 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 to the 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 the island of Tasmania and further along the meridian to Antarctica. Thus, as seen 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 coasts of the bordering continents are slightly indented, therefore there are very few seas - in the north there are the Red Sea, the Persian Gulf, the Arabian Sea, the Bay of Bengal and the Andaman Sea, and in the east there are the Timor and Arafura Seas.

Indian Ocean Depth

At the bottom of the Indian Ocean, in its central part, there are several deep-sea basins, separated by underwater ridges and underwater plateaus, and along the Sunda island arc there is deep sea Sunda Trench. In it, oceanologists found the deepest hole on the ocean floor - 7130 meters from the surface of the water. The average depth of the ocean is 3897 meters. The most large islands in the Indian Ocean - 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 lot of coral islands.

Indian Ocean temperature

The water in the Indian Ocean is warm. In June - August, closer to the equator, its temperature, like in a bath, is 27-28 ° 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 °C. But from the equator south to Antarctica, the ocean water temperature changes to 26 and even 28 °C. From the north it is limited by the shores of the Eurasian continent. From the south - a conditional line connecting the extremities of South Africa and Australia. In the west is Africa.

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

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

Underwater volcanoes in these troubled areas emit so much material from the depths that new islands appear from time to time. Many coral reefs and atolls are found in the local warm waters. Navigating ships in the Indian Ocean is not easy. During stormy periods, in some of its areas, huge waves as high as a five-story building have been recorded!.. Giant catastrophic tsunami waves are not such a rare exotic for the inhabitants of the Indian Ocean basin.

The Indian Ocean makes up 20% of the World Ocean by volume. It is bounded by Asia to the north, Africa to the west and Australia to the east.

In the zone 35° S. passes the conventional 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. It is in the Indian Ocean that the saltiest sea in the world, the Red Sea, is located.

The ocean is also rich in minerals. The area 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, greatest depth - Sunda Trench (7729 m).

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

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

Main currents of the Indian Ocean

Warm:

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

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

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

Mozambican- another branch of the South Trade Wind Current. It washes the coast of Africa and in the south merges with the Agulhas Current. Average temperature - 25°C, speed - 2.8 km/h.

Agulhas, or Cape Agulhas Current- a narrow and fast current running 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.

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

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

The underwater world of the Indian Ocean

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

The tropical coastline is represented by vast thickets of mangroves, home to numerous colonies of crabs and amazing fish - mudskippers. Shallow waters provide excellent habitat for corals. And in temperate waters brown, calcareous and red algae grow (kelp, macrocysts, fucus).

Invertebrate animals: numerous mollusks, a huge number of species of crustaceans, jellyfish. There are many sea snakes, especially poisonous ones.

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

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

Despite the richness of the Indian Ocean, seafood fishing here is poorly developed. The catch is only 5% of the world's. Tuna, sardines, stingrays, lobsters, lobsters and shrimp are caught.

Indian Ocean exploration

Coastal countries of the Indian Ocean - hotspots ancient civilizations. That is why the development of the water area began much earlier than, for example, the Atlantic or Pacific Ocean. Approximately 6 thousand years BC. The waters of the ocean were already plied by the shuttles and boats of ancient people. The inhabitants of Mesopotamia sailed to the coasts of India and Arabia, the Egyptians conducted 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 compiled detailed navigation maps of the coastal zones of the Indian Ocean, explored the waters near the eastern coast of Africa, India, the islands of Java, Ceylon, Timor, and the Maldives.

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

1497 - Vasco de Gama's voyage and exploration of the eastern 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 discovery of Australia.

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

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

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

1990s - present day: studying the ocean using satellites, compiling a detailed bathymetric atlas.

2014 - after the crash of a 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 last century, this happened to three ships at once: the Cabin Cruiser, the tankers Houston Market and Tarbon.

Introduction

1.History of the formation and exploration of the Indian 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. It is bounded in the north 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 - Maldives, Laccadive, 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 tops are, as a rule, extinct volcanoes. The floor 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 deaths, 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.

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 South of 55° S. 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 most saline waters are the Persian Gulf, Red and Arabian Seas: this is explained by intense evaporation with a small amount fresh water, brought to 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 Indian Ocean and its structure

Bottom sedimentsIndian 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 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 subdivided 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, the Northern part The Mascarene Ridge is a structure that appears to be 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

shows vast territories and a large number interesting islands for researchers and tourists. If you don't yet know where it is located Indian Ocean map will tell you.

Indian Ocean Current Map

The underwater world of the Indian Ocean

Rich and varied underwater world of the Indian Ocean. In it you can find both very small aquatic inhabitants and large and dangerous representatives of the aquatic world.

Since ancient times, man has been trying to subjugate the ocean and its inhabitants. In all centuries, hunting has been organized for the inhabitants of the underwater world of the Indian Ocean.

There are even those that can cause trouble for a person. For example, these are sea anemones that live in almost all the seas and oceans of our planet. Sea anemones can be found not only in the depths, but also in the shallow waters of the Indian Ocean. They almost always feel hungry, so they sit hidden with their tentacles widely spaced. Predatory representatives of this species are poisonous. Their shot can hit small organisms and also cause burns in people. Sea urchins, seals, and the most exotic species of fish live in the waters of the Indian Ocean. The flora is diverse, which makes diving truly exciting.

Fishes in the Indian Ocean

Indian Ocean fauna not fully studied. In warm waters you can find a variety of marine animals. Fishing is carried out off the coast of the Indian Ocean. The fishery is mainly of local importance, however, a large amount of fish is also supplied to world markets. In addition, the Indian Ocean is rich in various natural resources.

Inhabitants of the Indian Ocean may not always be eaten. For example, the Bay of Bengal is very rich in fish stocks, but the technical backwardness of fishing and the low degree of knowledge of the waters of the bay prevent fishermen and large companies from catching fish. Fishing occurs during the winter monsoon, which is characterized by light winds and sunny weather. Some types of fish are dangerous to humans or cause trouble, as well as Indian Ocean jellyfish.

Indian Ocean water temperature

The water surface temperature is 29 0 off the coast of Australia. This is the highest figure for this ocean. In the subtropics, its waters are colder, with an average temperature of 20 degrees. Icebergs, which in some cases float quite high to southern latitudes, have a slight influence on the water temperature and its salinity.

Indian Ocean Depth

Like other oceans of the world, the Indian Ocean contains seas. There are five of them in total. They form the area and depth of the Indian Ocean. Thus, the Arabian Sea occupies more than 3.5 thousand square kilometers, the greatest depth of which is almost 6 km. While the greatest depth of the Pacific Ocean is the Mariana Trench, which is 11 km deep. 22 m then Indian Ocean depth much more modest. The deepest place is considered to be the Java Trench, located off the island of Java, the depth of which is almost 7.5 km.

Which countries are washed by the Indian Ocean?

The waters of the Indian Ocean wash a huge number of mainland and island countries. Island countries, which are located on the coast of the Indian Ocean:

• Comoros Islands,
• Mauritius.

Among mainland countries it is worth noting

• Malaysia,
• Myanmar,
• Bangladesh,
• Iraq,
• Somalia,
• Oman,

And of course, in this ocean there are the Seychelles, beautiful, mysterious and alluring.

It is not for nothing that this pearl of the Indian Ocean - Seychelles, ranks among the top ten destinations for tourism and recreation in many countries of the world.

Indian Ocean area

The third largest on the globe, the Indian Ocean covers about 20% of the planet's water surface. Indian Ocean area is 76.17 million square kilometers and consists of the area of ​​its seas, bays, straits, islands and archipelagos. From space, Indian looks like a huge blue blanket on the body of the earth. Let's watch a short video about Aurora over the Indian Ocean filmed from space on board the ISS

Remember how the classic?

Towards the morning Aurora

Be the Star of the North...

Maybe Alexander Sergeevich, also somewhere in his soul, had in mind what we are talking about now?))))))

The volcanic island of Amsterdam is located in the Indian Ocean. This Island state in the Indian Ocean located at equal distances from the coasts of Australia, Africa and Antarctica. 85 kilometers from the island is the island of Saint-Paul, which is uninhabited, unlike its neighbor.

Since Amsterdam is a volcanic island, here you can encounter such a natural phenomenon as a volcanic eruption. The last time this event took place was in 1792. Island city in the Indian Ocean characterized by a mild and even climate. The coldest time of the year falls in July and August. During these months, the air temperature rarely rises above +11C. In February, on the island of Amsterdam the most high temperatures, fluctuating in the range of +16-+18 0 C.

Before capital island in the Indian Ocean was open, only grass and shrubs could be found here. People planted a large number of trees and other types of vegetation. Many settlers arrived. Nowadays the domestic economy is very well developed here and the territory of the island is densely filled with domestic animals and poultry. But not only pets inhabit Amsterdam. Many seabirds, penguins and seals can be found here.

Indian Ocean resorts

In the list of the very best, the Indian Ocean ranks as the warmest. The world's most exotic and popular resorts are located on its shores. As practice shows - Indian Ocean, resorts which are becoming more and more popular every day, is primarily of interest to tourists from the largest country in the region - India. Tourists appreciate it for its diversity, mild climate, and low prices. Resorts such as the UAE, Maldives, and Mauritius are also popular.

Indian Ocean - photo

So beautiful Indian Ocean exists on our planet. Would you like to swim in it?

Have a nice trip!
And go back to.

Africa is the second largest continent on Earth. Together with the islands belonging to it, it occupies an area of ​​30,284 thousand km2, the area of ​​the mainland without islands is 29,200 thousand km2. The continent has a special geographical position: the equator crosses it almost in the middle, i.e. Africa is located almost symmetrically in the northern and southern hemispheres. Most of the continent is located in the eastern hemisphere, and less - in the western.

Extreme points of the mainland:

1. Northern () - Cape Ras – Engela (37° 20′ N)
2. Yuzhnaya () – Cape Agulhas (34° 51′ S)
3. Zapadna () – Cape Almadi (17° 33′ W)
4. Eastern () – Cape Ras – Hafun (51° 24′ E)

The length of the continent from north to south is 8000 km, from west to east – 7500 km.

The continent is washed by the waters of two oceans: from the west - , from the east - . The western and southern coasts of the mainland, washed by the Atlantic Ocean, form the only large bay here - the Gulf of Guinea. In the extreme northeast, this gulf is divided into two independent gulfs - Biafra. Most of the bay has significant depths - up to 4 thousand m. And closer to the coast there are banks (banks are the shallow part of the bottom formed as a result of the death of benthic organisms and developed in the inner parts of the shelves), as well as numerous volcanic islands: Annobon, San Tome and Fernando Po (Bioco). All these islands are of volcanic origin, they are mountainous in relief, and have very fertile soils - Andosols. Together with the large Cameroon volcano on the continent, they form the so-called line. All of these volcanic massifs are associated with the strike of transform faults that cut the Mid-Atlantic Ridge from west to east. All these islands are composed of young alkali-basaltic volcanics. In addition, there are islands of continental origin in the Gulf of Guinea. These are the Greater and Lesser Elobey, the island of Corisco, Horatio, Tinosa Pequena and Tinosa Grande.

As you move north, the length of the continent increases greatly, and as you move south, it decreases.
Off the northwestern coast of Africa in the Atlantic Ocean there are also islands of volcanic origin associated with the spread of MOR transform faults here. These are islands such as: Madeira, Canary Islands and Cape Verde. The Cape Verde Islands are divided into two groups:

Leeward (Sotaventu) and Windward (Barlaventu). The Cape Verde Islands are very interesting and amazing. Most of Cape Verde Island is occupied by dry, gravelly highlands, called the “Moon Landscape”. It was here that the Americans filmed a film about how they conquered the moon.

There are a number of small volcanic islands far from the coastal zone. These are: Ascension, St. Helena, Tristan - yes - Cunha, Bouvet.

Cold currents pass in the northern and southern parts of the Atlantic Ocean off the coast of Africa. In the north there is the Canary Current, which brings water with a temperature of 15–16° to the shores of the mainland. The cold Bengal Current passes off the southwestern coast of Africa. The water temperature there is especially low (6 – 9° on the surface) due to the rise of cold deep waters - this process is called upwelling. Both cold currents have a significant impact on the climatic conditions of the western outskirts of Africa in tropical latitudes. In the Atlantic Ocean, the coastal part of Africa is very unstable - the depths come very close to the coast. A not wide strip of continental shallows is limited by sharp ledges that immediately lead to depths of up to 2000 - 3000 m. Only in the south at 20° S. The underwater Whale Ridge approaches the shores of the mainland.

The eastern and southern coasts of Africa are washed by the Indian Ocean. Here, not far from the coast, there are islands of coral origin - Mafia, Zanzibar and Pemba. Mainland ones include -, Seychelles and Socotra. The Comoros Islands are classified as volcanic. South of the equator, warm currents pass off the coast of Africa. Mozabique in the north and Cape Agulhas in the south. These two currents are formed from the South Trade Wind Current and cause winter temperatures off the coast of southeast Africa to rise to 20°C or more. The Somali monsoon current penetrates to the north from the equator, bringing relatively cold waters from the southern hemisphere in the summer of the northern hemisphere, and in winter changing its direction to the south and carrying relatively warm waters from the north.

The structure of the continent's surface is quite uniform. Plains and plateaus with heights from 200 to 1000 m predominate; there are few lowlands. The most extensive plateaus are East African and South African. Elevated areas alternate with basins, the most extensive of which are the Kalahara basin, etc. The highest point is (5895 m), the lowest is Lake Asal (-150 m). The average height is 600 m above sea level.

The relief features are associated with the history of the development of the continent. At the heart of the continent lies the ancient African Arabian Plate - part of the fractured Gandwana. The platform was formed by archaea and praterazoa and over 2-3 billion years acquired greater stability. Only Atlas Mountains in the north and the Cape in the south created by later movements of the earth's crust. The huge African hills experienced uplift and subsidence, while the northern part of the continent sank more often than it rose, and was flooded with seas. The crystalline foundation of the platform is covered by sedimentary rocks and only comes to the surface in the center of the Sahara and on the coast of the Gulf of Guinea. The relief of Eastern and Southern Africa was formed differently - the uplift of the earth's crust predominated, and giant faults, horsts and grabens were formed. Volcanic activity was actively developing. There are many lava plains here, grabens are occupied by lakes. Volcanic eruptions still occur today. The rift belt is home to volcanoes, including Mount Kilimanjaro.

Africa's mineral resources are rich. The location of deposits is closely related to geological history and tectonic structure. Eastern and Southern (“high”) Africa, where the surface is dominated by igneous crystalline and metamorphic rocks, is known for ores of ferrous and non-ferrous, noble and rare metals. Diamond deposits are confined to kimberlite volcanic pipes in the depths of the platform. In the strata of sedimentary rocks of North and West Africa, reserves of phosphorites, oil and natural gas (region of the Sahara Plate), table salt, and coal (Nigeria) have accumulated. Oil and gas are produced not only on land, but also on the Atlantic shelf. South Africa has significant reserves of coal, copper and uranium ores.

Africa is the hottest continent on the planet. In most of its part, the average temperature of any month is above +20 ° C, which is explained by the location of most of the continent between the tropics, where the sun stands high above the horizon throughout the year, and twice a year it is at its zenith. The seasons of the year differ more from each other in terms of the conditions of the holiday. Features are determined by circulation, on which the amount of precipitation and its pattern largely depend. A low pressure belt is formed over the equatorial part of the continent, and high pressure belts are formed in tropical latitudes. These belts move following the zenital position of the sun and determine the movement of equatorial, tropical and temperate air masses over the continent. Almost the entire continent is under the influence of constant winds - trade winds. The northeast trade winds that come from land bring almost no moisture, while the southeast trade winds carry it from the Indian Ocean. In subtropical latitudes during the winter months, precipitation falls from moderate air masses dominated by westerly air transport from the Atlantic Ocean. Relief also influences the distribution of precipitation. The steep and high shores of the continent make it difficult for humid winds to penetrate from the ocean into the interior of the continent. More precipitation falls on the windward slopes of the mountains. On the slopes of Mount Cameroon, their number reaches 10,000 mm per year. The driest areas are located not only inside the mainland, but also in its Pryakian parts. Thus, the western coast of the mainland in tropical latitudes is washed by cold currents. The air above them becomes colder than in the upper layers, and its flow is difficult. Apart from dew and fog, there is almost no precipitation here. On the mainland there are equatorial, two subequatorial, two tropical and two subtropical. Within some of them there are differences that are determined by the amount of precipitation and its regime.

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.

There are relatively few islands. The largest of them are of continental origin and are located near the coasts of 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 - the Maldives, Laccadives, Chagos, Cocos, most Andaman, etc.

Shores on the north-west. and the East are indigenous, in the north-east. and in the West, alluvial deposits predominate. Coastline slightly indented, with the exception of the northern part of the Indian Ocean. Almost all seas and large bays (Aden, Oman, Bengal) are located here. In the southern part 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 in Antarctica and northwestern Australia up to 300-500 m). The continental slope is a steep (up to 10-30°) ledge, in places dissected by the underwater valleys of the Indus, Ganges, and other rivers. In the northeastern part of the ocean is the Sunda Island Arc and the associated Sunda Trench, to which the maximum depths(up to 7130 m). The bed of the Indian Ocean is divided by ridges, mountains and swells into a number of basins, the most significant of which are the Arabian Basin, the Western Australian Basin, and the African-Antarctic Basin. The bottom of these basins is formed by accumulative and hilly plains; the former are located near continents in areas with an abundant supply of sedimentary material, the latter - in the central part of the ocean. Among the numerous ridges of the bed, the meridional East Indian Ridge, which connects in the south with the latitudinal Western Australian Ridge, stands out due to its straightness and length (about 5,000 km); large meridional ridges stretch south from the Hindustan Peninsula and the island. Madagascar. Volcanoes are widely represented on the ocean floor (Mt. Bardina, Mt. Shcherbakova, Mt. Lena, etc.), which in some places form large tracts(to the north of Madagascar) and chains (to the east of the Cocos Islands). Mid-ocean ridges are a mountain system consisting of three branches diverging from the central part of the ocean to the north (Arabian-Indian ridge), southwest. (West Indian and African-Antarctic ridges) and South-East. (Central Indian Ridge and Australian-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; Characterized by transverse faults, along which horizontal displacements of the bottom up to 400 km are noted. The Australian-Antarctic Rise, in contrast to the median ridges, is a more gentle swell 1 km high and up to 1500 km wide.

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

The climate of the northern Indian Ocean is monsoonal; in summer, when an area of ​​low pressure develops over Asia, southwestern flows of equatorial air dominate here, in winter - northeastern flows of tropical air. To the south 8-10° S. w. atmospheric circulation is much more constant; Here, in tropical (summer and subtropical) latitudes, stable southeastern trade winds dominate, and in temperate latitudes, extratropical cyclones moving from West to East dominate. In tropical latitudes in the western part there are hurricanes 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 drops in summer to 20-25 °C at 30° S. latitude, up to 5-6 °C at 50° S. w. and below 0 °C south of 60 ° S. w. In winter, the air temperature varies from 27.5 °C at the equator to 20 °C in the northern part, to 15 °C at 30 ° S. latitude, up to 0-5 °C at 50° S. w. and below 0 °C south of 55-60 ° S. w. Moreover, in the southern subtropical latitudes all year round, the temperature in the West, under the influence of the warm Madagascar Current, is 3-6 °C higher than in the East, where the cold Western Australian Current exists. Cloudiness in the monsoon northern part of the Indian Ocean is 10-30% in winter, up to 60-70% in summer. In summer, the greatest amount of precipitation is observed here. The average annual precipitation in the east of the Arabian Sea and the Bay of Bengal is more than 3000 mm, at the equator 2000-3000 mm, in the west of the Arabian Sea up to 100 mm. In the southern part of the ocean, the average annual cloudiness is 40-50%, south of 40° S. w. - up to 80%. The average annual precipitation in the subtropics is 500 mm in the east, 1000 mm in the west, in temperate latitudes it is more than 1000 mm, and near Antarctica it drops to 250 mm.

The circulation of surface waters in the northern part of the Indian Ocean has a monsoon character: in summer - northeastern and eastern currents, in winter - southwestern and western currents. In the winter months between 3° and 8° S. 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 Winds in the north, Madagascar and Agulhas in the West and cold currents - the Western Winds current in the South and Western Australian in the East. South of 55° S. w. Several weak cyclonic water circulations develop, closing off the coast of Antarctica with an eastern current.

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

Surface water temperatures reach a 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 it 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° south. latitude, up to 3-5 °C at 50° S. w. and below -1 °C south of 55° S. w. In the winter of the Northern Hemisphere, the temperature in the north is 23-25 ​​°C, at the equator 28 °C, at 30 ° S. w. 21-25 °C, at 50° S. w. from 5 to 9 °C, south of 60° S. w. 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 southern subtropical latitudes, salinity exceeds 35.5‰ (maximum 36.5‰ in summer, 36.0‰ in winter), and to the south 40° S. w. decreases to 33.0-34.3‰. The highest water density (1027) is observed in 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 layer of water increases from 4.5 ml/l in the northern part of the Indian Ocean to 7-8 ml/l south of 50° south. w. At depths of 200-400 m, the oxygen content in absolute value is significantly lower 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 Antarctic latitudes it is blue, in places with greenish tints.

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).

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

Flora and fauna

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, a fish capable of long time exist in the air. 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 macrocystis) 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. Of the 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 copepod crustaceans (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. Sea turtles and large marine mammals (dugongs, toothed and toothless whales, pinnipeds) are common. 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.