Indian Ocean

Indian Ocean
Indian Ocean-CIA WFB Map.png
Extent of the Indian Ocean according to The World Factbook
Location South Asia, Southeast Asia, Western Asia, Northeast Africa, East Africa, Southern Africa and Australia
Type Ocean
Max. width 6,200 mi (10,000 km)
Surface area 70,560,000 km2 (27,240,000 sq mi)
Average depth 3,741 m (12,274 ft)
Max. depth 7,906 m (25,938 ft)
Earth's oceans
(World Ocean)


The Indian Ocean is the third largest of the world's oceanic divisions, covering 70,560,000 km2 (27,240,000 sq mi) (approximately 20% of the water on the Earth's surface). It is bounded by Asia on the north, on the west by Africa, on the east by Australia, and on the south by the Southern Ocean or, depending on definition, by Antarctica. It is named after India.

The deepest point in the Indian Ocean is in the Java Trench near the Sunda Islands in the east, 7500 m (25,344 feet) deep. The average depth is 13,002 feet deep. The Indian Ocean is the third largest ocean, 28,350,000 square miles in size. The majority is in the southern hemisphere.


The Indian Ocean is the warmest ocean in the world. Long-term ocean temperature records show a rapid, continuous warming in the Indian Ocean, at about 0.7–1.2 °C (1.3–2.2 °F) during 1901–2012. Indian Ocean warming is the largest among the tropical oceans, and about 3 times faster than the warming observed in the Pacific. Research indicates that human induced greenhouse warming, and changes in the frequency and magnitude of El Niño events are a trigger to this strong warming in the Indian Ocean.

Marine life

Among the tropical oceans, the western Indian Ocean hosts one of the largest concentration of phytoplankton blooms in summer, due to the strong monsoon winds. The Indian Ocean accounts for the second largest share of the most economically valuable tuna catch. Its fish are of great and growing importance to the bordering countries for domestic consumption and export. Fishing fleets from Russia, Japan, South Korea, and Taiwan also exploit the Indian Ocean, mainly for shrimp and tuna.

Research indicates that increasing ocean temperatures are taking a toll on the marine ecosystem. A study on the phytoplankton changes in the Indian Ocean indicates a decline of up to 20% during the past six decades. The tuna catch rates have also declined abruptly during the past half century, mostly due to increased industrial fisheries, with the ocean warming adding further stress to the fish species.

Endangered marine species include the dugong, seals, turtles, and whales.

An Indian Ocean garbage patch was discovered in 2010 covering at least 5 million square kilometres (1.9 million square miles). Riding the southern Indian Ocean Gyre, this vortex of plastic garbage constantly circulates the ocean from Australia to Africa, down the Mozambique Channel, and back to Australia in a period of six years.

In 2016, UK researchers from Southampton University identified six new animal species at hydrothermal vents beneath the Indian Ocean. These new species were a "Hoff" crab, a "giant peltospirid" snail, a whelk-like snail, a limpet, a scaleworm and a polychaete worm.


Indian Ocean for Kids. Kiddle Encyclopedia.