A-Z Blogging Challenge: O Stands For: Oceans

(An example of the five major oceans and the World Ocean. SOURCE)

71% of Earth is covered by ocean. The area of the World Ocean--which is the Atlantic, Arctic, Indian, Pacific, and Southern Oceans combined as a single body of salt water--is 361 million square kilometers (139 million square miles), and is approximately 1.3 billion cubic kilometers (310 million cubic miles) in volume. The average depth is 3,790 meters (12,430 feet), and the deepest point is 10,924 meters (6.787 miles), at the Mariana Trench.

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99% of Earth's living space is provided by the oceans--it is estimated they provide 300 times the habitable volume of land habitats. 90% of of that living space exists in the deep sea, the area below 200 meters (660 feet). Around 230,00 marine species are currently known, but that number could be up to ten times higher.

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Humans have explored less than 10% of the ocean. The Challenger II reached the Mariana Trench in 1951 and named its deepest point Challenger Deep, and the Trieste also reached the Trench in 1960 with a two-man crew, but much of the ocean floor is still unmapped and unknown.

News and information on ongoing and past projects, such as the Indonesia-USA Deep-Sea Exploration and the exploration of the deep reefs of the Indo-Pacific, can be found HERE.