Indian Ocean | Research & Encyclopedia Articles

The Indian Ocean, with an area of 75 million square kilometers, is the smallest of the three oceans bounded by Africa, Asia, Australia, and the Antarctic. Nevertheless occupying a huge area, the Indian Ocean extends over some 10,000 kilometers from South Asia to the Antarctic on the one side, and from South Africa to Tasmania on the other. The Indian Ocean accommodates 15 percent of the earth's total surface and occupies 21 percent of all ocean surfaces. While the mean depth is around 3,900 meters, its maximum depth is 7,125 meters (Java Trench). The seabed of the Indian Ocean is rather complex, with a multifold topography that includes huge basins as well as large ridges.

The vast area of the Indian Ocean is commonly divided into various sectors. The Arabian Sea and the Bay of Bengal are the major seas that bound the Indian peninsula, while the Lakshadweep and AndamanSeas are the minor seas around the homonymous Lakshadweep and Andaman Islands; the latter are further extended by the Nicobar Islands. The Arabian Sea is straddled by two important branches, the Gulf of Oman (elongated by the Persian Gulf) and the Gulf of Aden, which extends into the Red Sea. In 1869 the Red Sea was connected with the Mediterranean Sea by the gigantic Suez Canal, opening a new era of sea trade between Europe and Asia. The Suez Canal is still the leading shipping route between the two continents. Along its southern region the Indian Ocean is commonly called the Indian South Polar Sea, except for the Great Australian Bight that bounds South Australia. For the big islands lying opposite continental land masses, such as Madagascar, Sri Lanka, and Sumatra, the Mozambique Channel, Palk Strait, and Strait of Malacca, respectively, serve as connecting seas.

The Indian Ocean accommodates many isolated islands and island groups without hosting large island archipelagos. Apart from Madagascar and Sri Lanka, large island nations, a few small island groups are of importance, some of which have nowadays become tourist destinations. Comparably big island groups include the Comoros, Amirante, Seychelles, and Mascarene Islands (including Mauritius and Réunion), the Lakshadweep, Andaman, and Nicobar Islands as well as the Maldives, Chagos Archipelago, New Amsterdam, Saint Paul, the Kergueles, Heard, Marion, Prince Edward, Crozet, Christmas, and Cocos Islands, all dispersed across the vast Indian Ocean.

Politically the various islands and island groups are independent small island nations or still belong to other countries. In the past all the islands were colonial outposts of various European powers, as their old colonial names still underline; they gained independence only after the Second World War (and sometimes decades later).

The Indian Ocean is divided by the equator in its northern part, and most of it is located south of the equator. As a result the climate incorporates (from north to south) the monsoon, the passates or the major air current also known as the tropical easterlies (south of the equator), and the temperate climates under the westerlies (farther south). Characteristic of all climate zones is the oceanic impact that weakens the temperature contrasts between the seasons. By nature the Indian Ocean and bounding coastal land surfaces rarely have tropical cyclones or storms, except for the Bay of Bengal and Mascarene Islands, which are irregularly visited by cyclones.

Since early times the northern Indian Ocean was heavily traveled between Arabia and India by Arabian seafarers who sailed with the seasonal monsoon winds. While in ancient times Egyptians, Arabs, and Chinese traveled the Indian Ocean, the European colonial discovery of the Indian Ocean occurred only in 1497, with the legendary expedition by Vasco da Gama, who first rounded the Cape of Good Hope to cross the Indian Ocean toward India. Traditionally the countries bordering the northern Indian Ocean, such as Arabia, India, and the countries of Southeast Asia, were best known to the foreign sailors and merchants because of their spices, gems, gold, ivory, and other rare goods. Only since the colonial age commencing with the sixteenth century did a regular trade develop across the Indian Ocean between Europe and Asia. In modern times air travel has absorbed much of the commerce between Europe and the countries around the Indian Ocean.

Fishing is a traditional practice on the lands bordering the Indian Ocean. Nowadays, however, oil and gas are heavily exploited, and offshore wells represent valuable resources, mostly in the Persian Gulf nations of the United Arab Emirates, Saudi Arabia, Iran, and the emirates of Kuwait, Qatar, and Bahrain.

Though most islands in the Indian Ocean are uninhabited, some are heavily populated, even seriously overpopulated, by native peoples. The mostly poor living conditions are based on marginal subsistence agriculture. Having limited resources for development, some islands and island groups benefit from tourism as a profitable industry; these include Mauritius and Réunion, Comoros and Seychelles, and the Maldives. All such islands are favored destinations, mostly for European tourists, who are attracted by the "exoticness," the tropical climate and sandy beaches, and superb diving conditions (in case of the Maldives, due to their nature as coral islands).

Life on all the small islands in the Indian Ocean may have a hazardous future, due to the impact of global warming, which will lead to rapidly shrinking island surfaces and result in coasts flooded and life conditions worsened by the impact of increasing hurricanes and typhoons in the region. Many instances of serious coastal erosion processes have already occurred on the islands in recent times. The Maldives are worst afflicted because most of the land surfaces of all 1,200 small islands are not higher than half a meter above sea level. If critical predictions of a sea level rise of 50 to 100 centimeters are borne out during this century, disastrous results must be expected for many millions of coastal inhabitants in South Asia, mostly in India and Bangladesh.

Arnberger, Hertha, and Erik Arnberger. (2001) The Tropical Islands of the Indian and Pacific Oceans. Vienna: Austrian Academy of Sciences Press.

Toussinet, Auguste. (1966) History of the Indian Ocean. Chicago: University of Chicago Press.

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