The search for MH370 has now expanded west to include the massive Indian Ocean. Here are five things about the Indian Ocean.
1. Covering about 73,440,000 sq km, the Indian Ocean is the world's third largest ocean after the Pacific and the Atlantic oceans. It accounts for 20 per cent of the water on the Earth's surface. It is bounded by South Asia to the north, Africa to the west, Indonesia and Australia to the east and Antarctica to the south.
2. The Indian Ocean contains several island nations: Comoros, Madagascar, Maldives, Seychelles and Sri Lanka. Its island group also includes the Mascarenes which comprises Mauritius, Reunion and related islands.
3. Its average depth is 3,890m. It reaches its greatest depth of 7,450m in the Java Trench, south of Java. There are two main circulation systems in the ocean - the south equatorial current and the monsoon drift - which influence the annual monsoon seasons. The clockwork regularity of the monsoon winds and rains have, historically, made this ocean a main transport artery between the East and the West. Egyptians used it to travel down the east coast of Africa, Indonesians sailed across it to settle in Madagascar and China also crossed it to reach Africa. Tankers and ships still crisscross the ocean daily.
4. It is rich in natural resources such as oil, gas and minerals. As a result, it is mined by its border nations such as India, which extracts magnesium. Its resources are so rich that even China and Germany have obtained permission to plumb its depths. It supplies about 40 per cent of the world's offshore oil production.
5. There is rich marine life in the Indian Ocean. There are humpback whales and whale sharks. In the shallower waters bordering different countries, there are reef habitats which host everything from turtles and clown fish to crustaceans and molluscs. An order of fish thought to be extinct, the coelacanths, are also found in the Indian Ocean. Two species of coelacanths, which date back to the Cretaceous era, have been discovered in the West Indian Ocean and the East Indian Ocean.