The Atlantic and Indian Oceans

The Indian Ocean lies between four continents — Africa, Eurasia, Australia and Antarctica — and most of it is in the Southern Hemisphere. Its name comes from the Sanskrit word for “river” (Hind–Sind). The textbook gives its area as 76 million km² (without seas about 70 million km²). In ancient times Arabs, Sumerians and Phoenicians sailed it; in the 7th–12th centuries the Arabs knew it very well; in 1498 V. da Gama opened the sea route to India, and A. Tasman (1642–1643) and J. Cook (1771–1775) explored it. In the 20th century the “Challenger” and the UNESCO-led International Indian Ocean Expedition (1960s) worked here. Its floor has mountain ranges in three branches; the deepest point is the Java (Sunda) Trench (up to about 7 700 m). In the north the water temperature is +25…+28 °C; the Indian Ocean has seasonal monsoon winds: in summer from sea to land (humid, rainy), in winter from land to sea (dry). Salinity is above the World Ocean average; the saltiest part is the Red Sea (42 ‰) and the least salty the Bay of Bengal (30–34 ‰), because rivers such as the Ganges and Brahmaputra pour in much fresh water. Life is very rich around coral reefs. The most oil is shipped across this ocean (from the Persian Gulf), and pearls are gathered. The Indian Ocean earthquake of 26 December 2004 caused a devastating tsunami.