It has the fewest seas. It has a peculiar bottom topography, and in the northern part - a special system of winds and sea currents.

Mostly located in the Southern Hemisphere between, and. Its coastline is slightly indented, with the exception of the northern and northeastern parts, where almost all the seas and large bays are located.

Unlike other oceans, the mid-ocean ridges of the Indian Ocean consist of three branches radiating from its central part. The ridges are dissected by deep and narrow longitudinal depressions - grabens. One of these huge grabens is the Red Sea depression, which is a continuation of the faults in the axial part of the Arabian-Indian mid-ocean ridge.

Mid-ocean ridges divide the bed into 3 large sections that are part of three different ones. The transition from the ocean floor to the continents is gradual everywhere, only in the northeastern part of the ocean is the arc of the Sunda Islands, under which the Indo-Australian lithospheric plate plunges. Therefore, a deep-sea trench about 4000 km long stretches along these islands. There are more than a hundred active volcanoes, among which the famous one is Krakatau, earthquakes often occur.

At the surface of the Indian Ocean depends on the geographical latitude. The northern part of the Indian Ocean is much warmer than the southern part.

Monsoons form in the northern part of the Indian Ocean (to the north of 10 S). In summer, the southwest summer monsoon blows here, carrying moist equatorial air from the sea to land, in winter - the northeast winter monsoon, carrying dry tropical air from the continent.

The system of surface currents in the southern half of the Indian Ocean is similar to the system of currents in the corresponding latitudes of the Pacific and Atlantic oceans. However, north of 10°N. a special regime of water movement arises: monsoonal seasonal currents appear, changing direction to the opposite twice a year.

The organic world of the Indian Ocean has much in common with the organic world of the Pacific and Atlantic Oceans in the corresponding latitudes. In the shallow waters of the hot zones, coral polyps are common, creating numerous reef structures, including islands. Among the fish, the most numerous are anchovies, tuna, flying fish, sailfish, and sharks. The tropical coasts of the mainland are often occupied by mangroves. They are characterized by peculiar plants with terrestrial respiratory roots and special animal communities (oysters, crabs, shrimps, mudskipper fish). The bulk of the ocean animals are invertebrate planktonic organisms. In tropical coastal areas, sea turtles, poisonous sea snakes, endangered mammals - dugongs are common. Whales, sperm whales, dolphins, and seals live in the cold waters of the southern part of the ocean. Among the birds, the most interesting are the penguins that inhabit the coasts of South Africa, Antarctica and the islands of the temperate zone of the ocean.

Natural resources and economic development

The Indian Ocean has great biological wealth, but fishing is mainly limited to coastal areas, where, in addition to fish, lobsters, shrimps, and mollusks are caught. In the open waters of hot zones, tuna is fished, and in cold waters - whales and krill.

The most important are oil and natural gas deposits. The Persian Gulf with the land adjacent to it stands out especially, where 1/3 of the oil of the foreign world is extracted.

In recent decades, the coasts of warm seas and the islands of the northern part of the ocean have become increasingly attractive for people to relax, and the tourism business is booming here. Through the Indian Ocean, the volume of traffic is much less than through the Atlantic and Pacific Oceans. However, it plays an important role in the development of the countries of South and Southeast Asia.

The Indian Ocean is the third largest ocean on Earth, covering about 20% of its water surface. Its area is 90.17 million km2; volume - 210 million km3. The boundary between the Indian and Atlantic Oceans runs along the meridian 20° East, and between the Indian and Pacific Oceans runs along the meridian 147° East. The northernmost point of the Indian Ocean is located at approximately 30° north latitude in the Persian Gulf. The width of the Indian Ocean is approximately 10,000 km between the southern points of Australia and Africa. The nature of the Indian Ocean has many similarities with the nature of the Pacific Ocean, especially in the organic world of the two oceans. The Indian Ocean has a peculiar position on the planet: most of it lies in the South hemisphere. In the north, it is limited by Eurasia and has no connection with the Arctic Ocean. The ocean shores are slightly indented. There are relatively few islands. Large islands are located only on the border of the ocean. There are volcanic and coral islands in the ocean.
The Indian Ocean is located entirely in the Eastern Hemisphere between Africa - in the west, Eurasia - in the north, the Sunda Islands and Australia - in the east, Antarctica - in the south. The Indian Ocean in the southwest communicates widely with the Atlantic Ocean, and in the southeast with the Pacific. The coastline is poorly dissected. There are eight seas in the ocean, there are large bays.
The main part of the Indian Ocean lies in the equatorial, subequatorial and tropical zones, only the southern part covers high latitudes, up to the subantarctic. The main feature of the ocean's climate is the seasonal monsoon winds in its northern part, which is significantly influenced by land. Therefore, in the northern part of the ocean there are two seasons of the year - a warm, quiet, sunny winter and a hot, cloudy, rainy, stormy summer. South of 10°S dominated by the southeast trade wind. To the south, in temperate latitudes, a strong and steady westerly wind blows. The amount of precipitation is significant in the equatorial zone - up to 3000 mm per year. There is very little precipitation off the coast of Arabia, in the Red Sea and the Persian Gulf.
In the northern part of the ocean, the formation of currents is influenced by the change of monsoons, which rebuilds the system of currents according to the seasons of the year: summer monsoon - in the direction from west to east, winter - from east to west. In the southern part of the ocean, the most significant are the South Equatorial Current and the Western Wind Current. The south of the Indian Ocean is experiencing a significant cooling effect of Antarctica; here are the most severe regions of the ocean
The average surface water temperature is +17°С. The slightly lower average temperature is explained by the strong cooling effect of the Antarctic waters. The northern part of the ocean warms up well, is deprived of the influx of cold waters and is therefore the warmest. In summer, the water temperature in the Persian Gulf rises to +34°C. In the southern hemisphere, the temperature of the waters gradually decreases with increasing latitude. The salinity of surface waters in many areas is higher than average, and in the Red Sea it is especially high (up to 42 ppm).
It has a lot in common with the Pacific Ocean. The species composition of fish is rich and varied. Sardinella, anchovy, mackerel, tuna, dolphin, sharks, flying fish live in the northern part of the Indian Ocean. In southern waters - notothenia and white-blooded fish; there are cetaceans and pinnipeds. The organic world of the shelf and coral reefs is especially rich. Thickets of algae border the coast of Australia, South Africa, islands. There are large commercial accumulations of crustaceans (lobsters, shrimps, krill, etc.). In general, the biological resources of the Indian Ocean are still poorly studied and underutilized.
The northern part of the ocean lies in the tropical zone. Under the influence of the surrounding land and monsoon circulation, several aquatic complexes are formed in this belt, differing in the properties of water masses. Especially sharp differences are noted in the salinity of the waters.
In the equatorial zone, the temperature of surface waters almost does not change during the seasons. Above the numerous uplifts of the bottom and near the coral islands in this belt, a lot of plankton develops, and bioproductivity increases. The biological resources of the Indian Ocean have been used by the inhabitants of the coasts since time immemorial. And until now, handicrafts of fish and other seafood retain an important role in the economy of many countries. However, the natural resources of the ocean are used to a lesser extent than in other oceans. The biological productivity of the ocean as a whole is low; it increases only on the shelf and the continental slope.
A comprehensive study of the ocean began at the end of the 19th century. The most significant research was carried out by the British expedition on board the Challenger. However, until the middle of the twentieth century. The Indian Ocean has been poorly studied.

Geographical position. - the third largest ocean in terms of area and depth, covering about 20% of its water surface. Its area is 76 million km2. It extends from the coast of East Africa to Indonesia and Australia, and from the coast of India to Antarctica. Most of it is located in the Southern Hemisphere. The coastline of the ocean is slightly indented. Large islands in the ocean are: Sri Lanka, Madagascar, Kalimantan, etc. It includes 6 seas, among them: the Red and Arabian Seas, also bays: Bengal, Persian, Great Australian.

Relief. The average depth of the ocean is about 3700 m, and the maximum reaches 7729 m in the Java Trench. At the bottom of the Indian Ocean are huge sections of the earth's crust - the African, Indo-Australian and Antarctic plates. In the western part of the ocean, a system of mid-ocean ridges extends. They are associated with deep faults, areas of earthquakes and volcanism. Numerous basins are located between the ridges. The ocean shelf is poorly developed, only in the Persian Gulf it increases.

Minerals. In the shelf zone, tin ores, phosphorites, and gold have been found in rock deposits. The Persian Gulf and adjacent shelves contain the world's largest oil and gas fields. At the bottom of the basins of the Indian Ocean, ferromanganese nodules were found in large quantities.

Climate. The Indian Ocean is located in the equatorial, subequatorial and tropical climatic zones. The northern part is influenced by land. This is where the seasonal winds come from. monsoons. In summer, monsoons carry a huge amount of moisture to land (up to 3000 mm) in the Bay of Bengal area. To the south - from 10 ° to 30 ° S. sh. an area of ​​high pressure is formed, where the southeast trade wind dominates, in temperate latitudes - strong stable westerly winds. The south of the Indian Ocean is experiencing a significant cooling effect of Antarctica - these are the most severe areas of the ocean.

Currents and properties of ocean waters. Currents in the northern part depend on the monsoon winds, and their direction changes depending on the direction of the summer and winter monsoons. The monsoon, Somali and Trade wind currents form a strong circulation in the equatorial latitudes of the Indian Ocean. In the southern part of the ocean, the currents enter into a single ring-shaped movement of the waters of the World Ocean.

The Indian Ocean has a large salinity than other oceans. There is a pronounced zonality in the distribution of salinity here: the highest salinity, up to 42‰, is in the Red Sea and the Persian Gulf, the average salinity is 35‰, and in the Antarctic waters it drops to 33‰.

The Indian Ocean is also characterized by zonality in the distribution surface water temperatures . Between the equator and 10° N. sh. it is 30 °C, and to the north and south it drops to 24 °C. The closer the temperature is to Antarctica, the water drops from 15 °C to -1 °C.

organic world . The waters of the Indian Ocean serve as a habitat for various representatives of the animal world - sharks, whales, jellyfish, sea turtles, seals, sea elephants. The species composition of fish is rich - sardinella, anchovy, mackerel, etc. The tropical region of the ocean is one of the areas of wide distribution of coral polyps and the development of reef structures. A characteristic component of the landscape of the tropical coasts of the ocean are mangroves, where many oysters, shrimps, and crabs are found. Since ancient times, pearls have been mined in the ocean.

Main questions. What is the peculiarity of the ocean climate? What role does the Indian Ocean play in human economic activity?

The Indian Ocean is the third largest. The area of ​​the Indian Ocean is 76.2 million km 2, the average depth is 3711 m. The name of the ocean is associated with the name of the river indus- "sprinkler", "river".

Geographical position. The most characteristic feature of the geographical position of the Indian Ocean is that it is located almost entirely in the Southern Hemisphere and entirely in the Eastern. It is surrounded on all sides by Africa and Asia. Australia and Antarctica. There is no connection with the Arctic Ocean. The ocean includes 8 seas, the largest being Arabian. One of the warmest (up to 32°С) and salty seas in the world (38-42 ‰) is the Red Sea. It got its name from a significant accumulation of algae, giving the water a red color. (Fig.)

Relief The bottom of the Indian Ocean is diverse, its formation is associated with the history of the development of the Tethys Ocean. The shelf zone occupies a narrow strip and makes up only 4% of the total bottom area. The continental slope is very gentle. The ocean floor is crossed by mid-ocean ridges with an average height of about 1500 m. They are characterized by mid-ocean ridges and transverse faults. Individual volcanic mountains stand out. The greatest depth is 7729 m ( sunda trench).

Climate is determined by its location in the equatorial, subequatorial and tropical climatic zones. Only the southern part covers latitudes up to subantarctic. The climate of the northern part is greatly influenced by land. seasonal winds monsoons in summer they carry a huge amount of moisture from the ocean to land (in the area of ​​the Bay of Bengal up to 3000 mm per year), in winter they blow from land to the ocean. A southeasterly wind blows from the high pressure area towards the equator. trade wind. dominated in temperate latitudes westerly winds great strength, accompanied by cyclones. The proximity of Antarctica has a cooling effect on the southern margins of the ocean.

The Indian Ocean is called the "ocean of heated waters" for the high temperature of the water on the surface. The average temperature is +17°C. (Refer to the climate map for surface water temperatures and rainfall) The Persian Gulf region has the highest temperature (+34°C in August). The least amount of precipitation (100 mm) falls off the coast of Arabia.

On formation currents monsoons have a big impact. In the Indian Ocean, unlike the Pacific and Atlantic, in the Northern Hemisphere there is only one ring of currents - clockwise. (Show currents on a map).

The ocean has high salinity due to strong evaporation and low rainfall. . The average salinity is 34.7‰. Maximum salinity in the World Ocean in the Red Sea (41‰ ).

Natural resources and environmental problems. Everyone knows the largest deposits oil and gas in the Persian Gulf: Iran, Iraq, Kuwait, Saudi Arabia, etc. . (Fig. 4.5) At the bottom of the ocean basins, a large number of ferromanganese nodules, but their quality is worse than in the Pacific Ocean. They lie deep (4000m).

Animal world warm waters of the Indian Ocean is diverse, especially northern tropical part: a lot of sharks, sea snakes. It is a desirable habitat for coral polyps and the development of reef structures. (Fig. 1) Unfortunately, giant sea turtles are disappearing. In the mangroves of tropical coasts are found oysters, shrimp, crabs. In the open waters of tropical zones, fishing is common tuna. The Indian Ocean is famous for pearling. AT temperate latitudes inhabit toothless and blue whales, seals, elephant seal. The species composition of fish is rich: sardinella, mackerel, anchovy etc. But living organisms in the Indian Ocean are used less than in the Pacific and Atlantic. (rice) The richest organic world in the Red and Arabian seas, the Persian and Bengal bays. The temperate and polar latitudes of the ocean are habitats for large mammals: whales, dolphins. Decorates the ocean kingdom red and brown algae, fucus, kelp.

Dozens of states with a total population of about 2 billion people are located on the coast of the Indian Ocean. Basically it is developing countries. Therefore, the development of the natural resources of the ocean is slower than in other oceans. In the development of shipping, the Indian Ocean is inferior to the Atlantic and Pacific. Intensive oil transportation has led to a deterioration in water quality, a decrease in the stocks of commercial fish and seafood. Whaling has practically ceased. Warm waters, coral islands, the beauty of the Indian Ocean attract many tourists here.

The shelf of the northwestern part of the Indian Ocean has the richest oil reserves in the world. The Indian Ocean holds the third place in the world in terms of maritime transport in general and the first in terms of oil transportation (from the Persian Gulf).

1. Describe the geographic location of the ocean. *2. Practical work. Determine the length of the Indian Ocean at 10°S. sh. Make a guess about its size. **3. Make a tourist route along the coast of the Indian Ocean with a brief description of nature.

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

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

Location of the Indian Ocean

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

Seas and gulfs of the Indian Ocean

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

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

Indian Ocean islands

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

Underwater world of the Indian Ocean

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

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

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

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

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

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

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

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

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