Indian Ocean

The Indian Ocean is the third-largest of the world's five oceanic divisions. It covers 70,560,000 km² and is about 20% of the water on Earth's surface. It lies between Asia to the north, Africa to the west, and Australia to the east. To the south, it meets the Southern Ocean or Antarctica, depending on the borders.

Geologically, the Indian Ocean is the youngest of all the oceans. It formed about 20 million years ago when the Tethys Ocean broke apart. This ocean has unique features, such as narrow continental shelves. Its average depth is 3,741 meters, and it is the warmest ocean. It strongly influences the global climate through its interaction with the atmosphere.

The Indian Ocean has been a center for cultural and commercial exchange for a long time. It helped early humans move across continents and allowed civilizations to grow. Today, it is very important for global trade, especially for moving oil and other important resources. However, the ocean faces challenges such as climate change, overfishing, pollution, and disagreements over island territories.

Etymology

The Indian Ocean has been called by its current name since 1515. It was named after India, which touches the ocean. Before that, it was called the Eastern Ocean, compared to the Western Ocean, now the Atlantic. In Hindi, it is called हिंद महासागर, meaning "Ocean of India."

Chinese explorers, like Zheng He from the Ming dynasty, called it the Western Oceans. In Ancient Greek geography, the part of the Indian Ocean known to Greeks was the Erythraean Sea. In traditional South Asian geography, it was called the "Mahodadhi," split into two parts: Purvapayodhi (sunrise) and Apara (sunset).

Geography

The Indian Ocean is the third-largest ocean in the world. It covers about 70,560,000 km² and is roughly 20% of all the water on Earth. It is surrounded by Asia to the north, Africa to the west, and Australia to the east. At its southern edge, it meets the Southern Ocean or Antarctica.

The ocean's floor has spreading ridges. It is mostly in the Eastern Hemisphere, with the 90th meridian east running through the Ninety East Ridge. The Indian Ocean connects many regions, helping trade and travel between cultures and peoples.

Climate

The Indian Ocean has special features that affect weather and climate. It is part of a large warm area of water called the Tropical Warm Pool, which influences weather worldwide. Strong winds called monsoons change the ocean's currents each year. These winds bring rain to places like India and can sometimes cause storms near the Arabian Sea and the Bay of Bengal.

The Indian Ocean is the warmest ocean on Earth. Scientists have noticed it is getting warmer, partly because of human activities. This warming may continue to increase in the future. The ocean's temperature changes affect weather patterns.

Oceanography

The Indian Ocean has lots of dirt from rivers like the Indus and Ganges. In the south, near a cold area called the polar front, the ocean is full of life and has special kinds of dirt made from tiny creatures.

The water in the Indian Ocean moves because of winds called monsoons. There are big loops of water called gyres—one going clockwise in the north and another going the opposite way in the south. During some months, the water flow changes.

The Indian Ocean holds some of the biggest underwater fans and has special areas on the ocean floor. Water deep down comes mostly from a cold current that flows through areas near Antarctica. This deep water moves around the ocean in different paths.

Salt levels in the ocean change in different places. The water is saltiest in the Arabian Sea because there is more evaporation there. It is less salty in the Bay of Bengal because of rivers and rain.

Scientists found a big area of floating trash in the Indian Ocean. This trash patch moves around the ocean but will get smaller over many years.

The Indian Ocean sometimes has pieces of ice that float north, but not as far as in the Atlantic Ocean. The ocean’s water level is rising because the planet is getting warmer, but in some southern parts, the level is actually going down.

Marine life

The Indian Ocean is home to many interesting animals, like dolphins and surgeonfish. It also has places where tiny plants called phytoplankton grow a lot during certain times of the year. These plants are important because they are the start of the food chain that helps feed bigger fish.

The Indian Ocean has a lot of tuna, which is important for people who live near it. But, because the ocean is getting warmer and fishing is happening more, some fish and plants in the ocean are decreasing. There are also special areas like coral reefs, mangroves, and sea grass beds that help many sea animals live. These places are very important but are sometimes damaged by people building homes or fishing in ways that hurt the environment.

Biodiversity

Nine of Earth’s important areas for plants and animals are around the edges of the Indian Ocean. These places include Madagascar and its nearby islands, which have many special plants and animals.

These regions show how animals and plants change over time. For example, some animals first lived on Madagascar and later spread to Africa. Sadly, some animals, like the Dodo bird, have disappeared from these islands. Other places around the Indian Ocean, such as parts of Africa, India, and Southeast Asia, also have many different plants and animals, making them important to study and protect.

Geology

The Indian Ocean is the youngest of the world's major oceans. Its ocean floor began forming about 150 million years ago when the Indian Subcontinent and Madagascar moved away from Africa. The ocean is still growing because of active spreading ridges. These ridges are part of a global system of underwater mountain ranges.

These ridges in the Indian Ocean meet at a point called the Rodrigues Triple Point. They separate different tectonic plates, including the African, Indian, Antarctic, and Australian plates. The ocean has two deep trenches: the Java Trench and the Makran Trench. There are also underwater mountain ranges and ridges formed by hotspots. Hotspots are areas of volcanic activity deep within the Earth.

History

The Indian Ocean has connected people since ancient times, unlike the Atlantic and Pacific which often kept people apart. Its history is usually told from a European view because we have the most records from when Europeans began exploring and controlling the area. The history can be split into an ancient period and an Islamic period, followed by times of European control like the Portuguese, Dutch, and British. Some believe the time after World War II can also be split into competition for oil during the Cold War and then American influence.

The idea of an “Indian Ocean World” is fairly new but refers to a time when the ocean linked Asia, China, India, and Mesopotamia. This trade happened on its own, separate from European trade in the Mediterranean and Atlantic, until European colonial rule in the 1800s.

The Indian Ocean’s history is a mix of many cultures, groups of people, natural resources, and trade routes. It became more important in the 1960s and 1970s and has seen times of political trouble, especially with India and China becoming stronger powers.

First settlements

Early humans, known as Homo erectus, lived in India long ago. A big volcanic eruption around 74,000 years ago covered the area with ash and may have caused some of these early humans to disappear.

Modern humans, Homo sapiens, are believed to have spread from Africa to other parts of the world. One theory suggests they moved along the coasts of the Arabian Peninsula and southern Asia. This slow journey along the coast eventually led humans to Australia.

Over time, many people moved to areas around the Indian Ocean. About 5,000 to 6,000 years ago, six main cultural areas developed around the ocean: East Africa, the Middle East, the Indian Subcontinent, Southeast Asia, the Malay World and Australia. These areas traded with each other.

Antiquity

Trade across the Indian Ocean goes back at least 7,000 years. Cultures around the ocean shared ideas and goods with each other and with areas like the Mediterranean and the Persian Gulf. Before 2000 BCE, these cultures weren’t very connected, but bronze was used in Mesopotamia around 3000 BCE and later appeared in Egypt.

Trade routes developed along the ocean’s coasts. Local exchanges in the Persian Gulf, Red Sea, and Arabian Sea grew into a bigger network. Pottery from the Ubaid culture has been found in Bahrain, showing trade with Mesopotamia. The Sumerians traded many goods for copper, stone, timber, tin, dates, onions, and pearls. Ships carried goods between the Indus Valley civilisation and the Persian Gulf and Egypt.

The Red Sea was an important trade route explored by Egyptians and Phoenicians. The Greek explorer Scylax of Caryanda travelled to India for the Persian king Darius in the 6th century BCE. After Alexander the Great’s conquests, Greek explorers mapped the region. The Ptolemaic Egyptians focused more on military exploration than trade.

The Rub' al Khali desert separated parts of the Arabian Peninsula from the Indian Ocean, encouraging sea trade between the Red Sea, Persian Gulf, East Africa, and India. The monsoon winds helped sailors long before they were officially “discovered.” Indian wood has been found in Sumerian cities, showing trade from Akkad. Contacts between India and the Red Sea go back to 2300 BCE.

The Laccadive and Maldive islands were likely settled from the Indian mainland around the 2nd century BCE. They appear in a 9th-century account by the merchant Sulaiman al-Tajir. The Periplus of the Erythraean Sea, a guide from the first century CE, shows that Roman and Greek sailors knew about the monsoon winds. Settlers from Indonesia reached Madagascar around 1 CE using these winds.

Age of Discovery

Most islands in the Indian Ocean were not home to people until colonial times, except for the Maldives. Arab missionaries and merchants spread Islam along the western shores from the 8th century onward. Trade brought Arabic writing and rice to Eastern Africa. Muslim traders moved many people, with numbers increasing over time.

From 1405 to 1433, the Chinese admiral Zheng He led big fleets on voyages reaching East Africa. The Portuguese explorer Vasco da Gama was the first European to sail to India around the Cape of Good Hope in 1497. After 1500, the Portuguese attacked and took over cities along the African coast. European trading companies began, and slave trade grew. The Dutch, British, and French all set up colonies and continued the slave trade.

Late modern era

Scientific study of the Indian Ocean began in the early 1960s. Before that, exploration was limited. The Suez Canal opened in 1869, changing shipping routes and introducing new species to the Mediterranean. The canal’s planned expansion could bring economic growth but also environmental problems.

During colonial times, islands like Mauritius were important for trade. After World War II, colonial rule ended. In 2004, a huge earthquake caused tsunamis that affected fourteen countries around the ocean. In the late 2000s, pirate activity increased but later decreased due to navy patrols.

Malaysia Airlines Flight 370 disappeared in 2014 and is thought to have crashed in the southern Indian Ocean, but the plane’s location remains unknown.

The Chagos Archipelago’s ownership is disputed between the United Kingdom and Mauritius. In 2019, an international court said the UK should return the islands to Mauritius.

Geopolitics

The Indian Ocean is very important for global trade, especially for moving oil and other important fuels. People worry about how changes in the climate, illegal activities on the sea, and safety affect this area. Many big countries are also paying more attention to this part of the world.

Trade

The roads on the water in the Indian Ocean are very important for the world. More than 80 percent of the world's oil that travels by sea goes through the Indian Ocean, especially through important narrow paths like the Strait of Hormuz, the Strait of Malacca, and the Bab el-Mandab Strait.

The Indian Ocean helps connect big places like the Middle East, Africa, and East Asia to Europe and the Americas. It carries a lot of oil from places like the Persian Gulf and Indonesia. Many countries, such as Saudi Arabia, Iran, India, and Western Australia, get oil from the ocean areas near them. Beach sands and ocean areas also provide valuable minerals for countries like India, Pakistan, South Africa, Indonesia, Sri Lanka, and Thailand.

The water roads of the old Silk Road go through the Indian Ocean. This route carries many goods around the world. It starts from China, goes through places like Hanoi, Jakarta, Singapore, and Kuala Lumpur, then through the Strait of Malacca. From there, it continues to Colombo in Sri Lanka, Malé in the Maldives, and then to Mombasa in East Africa. From Mombasa, it goes to Djibouti, through the Red Sea and the Suez Canal into the Mediterranean Sea. It then reaches places like Haifa, Istanbul, and Athens before going to Trieste in Italy, connecting to Central and Eastern Europe.

The Silk Road has become important again because of better connections in Europe, the end of the Cold War, and efforts to trade freely around the world. Chinese companies have invested in ports in the Indian Ocean, like Gwadar, Hambantota, Colombo, and Sonadia. This has led to discussions about what these investments mean for the future. China is also working to increase trade in East Africa and in European ports such as Piraeus and Trieste.