Ocean: An ocean is a large expanse of sea that covers more than 75% of the entire Earth’s surface. This vastness gives a blue appearance to our planet when viewed from space. The ocean bed is composed of sand, gravel, mud and sediments. The average salinity of an ocean is 3.49% of the weight of seawater. Although the ocean is one continuous body of water yet is divided into four main areas: the Pacific, Atlantic, Indian and Arctic Oceans. The Atlantic, Indian and Pacific Oceans merge into icy waters around Antarctica. They combine to form the fifth ocean, most commonly called the Southern Ocean (frozen ocean).
Pacific Ocean: The Pacific Ocean is the largest ocean. It covers 30% of the Earth’s surface. The name ‘Pacific Ocean’ is derived from a Latin word Tepre Pacificum, which means ‘peaceful sea’. It separates Asia and Australia from the Americas. The depth of the Pacific Ocean is about 14,050 feet. The basins of the Pacific have around 75% of the total volcanoes on the Earth. The major rivers that drain into the Pacific directly are: the Hwang Ho, the Yangtze, the Colorado and the Columbia. Thousands of islands are spread over the Pacific.
Atlantic Ocean: The Atlantic Ocean is the second largest ocean of the world. It covers about one-fifth or 20% of Earth’s surface. To the east, it separates two continents Europe and Africa, and to the west North and South America. The name Atlantic comes from the Greek mythology, which means the Sea of Atlas. On the equator, it gets divided into two parts: the North Atlantic Ocean and the South Atlantic Ocean. The Missouri-Mississippi, the Amazon, the Congo and the Nile drain into this ocean.
Indian Ocean: The third largest ocean of the world’s oceanic division is the Indian Ocean. It covers about one-fifth of the total ocean area of the world. It is the youngest and smallest ocean of the Earth and has the most complicated formation process. To the north Indian Ocean is bounded by Iran, Pakistan, and India and to the south to Antarctica. To the east and southeast its water mingles with those of the Pacific. The deepest point of this ocean is near Java, which is 24,442 feet. The Indian Ocean controls the climatic pattern of the entire South-East Asia zone.
The Southern Ocean is also known as the Antarctic Ocean, the Great Southern Ocean, South Polar Ocean and Austral Ocean. It is surrounded by the southern portions of the Pacific, Atlantic and Indian oceans and their tributary seas.
