Water is an essential component of all life forms that exist over the surface of the earth. The earth, fortunately has an abundant supply of water on its surface. Hence, our planet is called the ‘Blue Planet’. About 71 per cent of the planetary water is found in the oceans. The boundaries between these Oceans have evolved over time for a variety of historical, cultural, geographical, & scientific reasons. The five oceans of the world from smallest to largest as defined by International Hydrographic Organisation (IHO) in 2000 are:
- The Arctic Ocean (Smallest),
- The Southern Ocean (Newest),
- The Indian Ocean,
- The Atlantic Ocean,
- The Pacific Ocean (Largest).
The various seas, bays, gulfs and other inlets are parts of these five large oceans.
The Concept of World Ocean
The contemporary concept of the World Ocean was coined in the early 20th century by the Russian oceanographer Yuly Shokalsky to refer to the continuous ocean that covers and encircles most of Earth.
Relief Features of the Oceans
The oceans are confined to the great depressions of the earth’s outer layer. A major portion of the ocean floor is found between 3-6 km below the sea level.
The ‘land’ under the waters of the oceans, the ocean floor, exhibits similar features as those observed over the land. The floors of the oceans are rugged with the world’s largest mountain ranges, deepest trenches and the largest plains. These features are formed, like those of the continents, by the factors of tectonic, volcanic and depositional processes.
World Oceans Day
The concept of a ‘World Oceans Day’ was first proposed by Canada in 1992 at the Earth Summit in Rio de Janeiro to raise awareness about the crucial role the ocean plays in our lives and the important ways people can help protect it. Later in 2008, by its resolution 63/111 of 5 December 2008, the UN General Assembly designated 8 June as World Oceans Day.
World Ocean Day 2020
The theme for World Ocean Day 2020 is ‘Innovation for a Sustainable Ocean’. For 2020, World Ocean Day is growing the global movement to call on world leaders to protect 30% of the world’s ocean by 2030 – a campaign called 30×30. By safeguarding a least 30% of our ocean through a network of highly protected areas we can help ensure a healthy home for both marine and human life.