The Indian Ocean is ecologically diverse, with important marine life and ecosystems like coral reefs, mangroves, and sea grass beds.

[16] In correspondence of the Shelf break, also known as Hinge zone, the Bouguer gravity ranges from 0 to 30 mGals that is unusual for a continental region of around 16 km thick sediments.

[29] In 1999, the Indian Ocean Experiment showed that fossil fuel and biomass burning in South and Southeast Asia caused air pollution (also known as the Asian brown cloud) that reach as far as the Intertropical Convergence Zone.

The monsoonal wind forcing leads to a strong coastal and open ocean upwelling, which introduces nutrients into the upper zones where sufficient light is available for photosynthesis and phytoplankton production.

The tuna catch rates have also declined 50–90% during the past half-century, mostly due to increased industrial fisheries, with the ocean warming adding further stress to the fish species.

[46] Coral reefs, sea grass beds, and mangrove forests are the most productive ecosystems of the Indian Ocean — coastal areas produce 20 tones of fish per square kilometre.

These areas, however, are also being urbanised with populations often exceeding several thousand people per square kilometre and fishing techniques become more effective and often destructive beyond sustainable levels while the increase in sea surface temperature spreads coral bleaching.

Several species on the islands of the Indian Ocean are textbook cases of evolutionary processes; the dung beetles,[52][53] day geckos,[54][55] and lemurs are all examples of adaptive radiation.

Other species still depend on fenced areas and management programs, including black rhinoceros (Diceros bicornis minor), African wild dog (Lycaon pictus), cheetah (Acynonix jubatus), elephant (Loxodonta africana), and lion (Panthera leo).

The Réunion hotspot (active 70–40 million years ago) connects Réunion and the Mascarene Plateau to the Chagos-Laccadive Ridge and the Deccan Traps in north-western India; the Kerguelen hotspot (100–35 million years ago) connects the Kerguelen Islands and Kerguelen Plateau to the Ninety East Ridge and the Rajmahal Traps in north-eastern India; the Marion hotspot (100–70 million years ago) possibly connects Prince Edward Islands to the Eighty Five East Ridge.

It grew in importance beginning in the 1960s and 1970s and, after the Cold War, it has undergone periods of political instability, most recently with the emergence of India and China as regional powers.

Sherds of Ubaid (2500–500 BCE) pottery have been found in the western Gulf at Dilmun, present-day Bahrain; traces of exchange between this trading centre and Mesopotamia.

The Sumerians traded grain, pottery, and bitumen (used for reed boats) for copper, stone, timber, tin, dates, onions, and pearls.

[84] Coast-bound vessels transported goods between the Indus Valley civilisation (2600–1900 BCE) in the Indian subcontinent (modern-day Pakistan and Northwest India) and the Persian Gulf and Egypt.

The Greeks began to explore the Indian Ocean following the conquests of Alexander the Great, who ordered a circumnavigation of the Arabian Peninsula in 323 BCE.

Indian wood have been found in Sumerian cities, there is evidence of Akkad coastal trade in the region, and contacts between India and the Red Sea dates back to 2300 B.C.

[82] The contemporaneous settlement of Madagascar by Austronesian sailors shows that the littoral margins of the Indian Ocean were being both well-populated and regularly traversed at least by this time.

The powerful monsoons also meant ships could easily sail west early in the season, then wait a few months and return eastwards.

[88] During the 1st and 2nd centuries AD intensive trade relations developed between Roman Egypt and the Tamil kingdoms of the Cheras, Cholas and Pandyas in Southern India.

The unknown author of the Periplus of the Erythraean Sea describes this route, as well as the commodities that were traded along various commercial ports on the coasts of the Horn of Africa and India circa 1 CE.

[92] From 1405 to 1433 admiral Zheng He said to have led large fleets of the Ming dynasty on several treasure voyages through the Indian Ocean, ultimately reaching the coastal countries of East Africa.

The Swahili people he encountered along the African east coast lived in a series of cities and had established trade routes to India and to China.

Maps that included the Indian Ocean had been produced by Muslim geographers centuries before the Ottoman conquests; Muslim scholars, such as Ibn Battuta in the 14th century, had visited most parts of the known world; contemporarily with Vasco da Gama, Arab navigator Ahmad ibn Mājid had compiled a guide to navigation in the Indian Ocean; the Ottomans, nevertheless, began their own parallel era of discovery which rivalled the European expansion.

For example, the goldband goatfish (Upeneus moluccensis) has replaced the red mullet (Mullus barbatus); since the 1980s huge swarms of scyphozoan jellyfish (Rhopilema nomadica) have affected tourism and fisheries along the Levantian coast and clogged power and desalination plants.

In the 1980s, during the Cold War, the South African regime acted to destabilise several island nations in the Indian Ocean, including the Seychelles, Comoros, and Madagascar.

India intervened in Mauritius to prevent a coup d'état, backed up by the United States who feared the Soviet Union could gain access to Port Louis and threaten the U.S. base on Diego Garcia.

[102] Malaysia Airlines Flight 370, a Boeing 777-2H6ER with 239 occupants on board, disappeared on 8 March 2014 and is alleged to have crashed into the southern Indian Ocean about 2,500 km (1,600 mi) from the coast of southwest Western Australia.

[105] In February 2019, the International Court of Justice in The Hague issued an advisory opinion stating that the UK must transfer the Chagos Archipelago to Mauritius.

[3] Beach sands rich in heavy minerals, and offshore placer deposits are actively exploited by bordering countries, particularly India, Pakistan, South Africa, Indonesia, Sri Lanka, and Thailand.

The Silk Road runs with its connections from the Chinese coast and its large container ports to the south via Hanoi to Jakarta, Singapore and Kuala Lumpur through the Strait of Malacca via the Sri Lankan Colombo opposite the southern tip of India via Malé, the capital of the Maldives, to the East African Mombasa, from there to Djibouti, then through the Red Sea over the Suez Canal into the Mediterranean, there via Haifa, Istanbul and Athens to the Upper Adriatic to the northern Italian junction of Trieste with its international free port and its rail connections to Central and Eastern Europe.