Oceans: 90 percent is still unmapped | Photo: Shutterstock

The World Oceans Day is celebrated on the 8th June. What should we know about the body of saline water that covers two-thirds of the planet's surface?

Earth is the only planet that is known to have large stable bodies of liquid water on its surface. Oceans generate most of the oxygen we breathe, and they regulate our climate.

Oceans clean the water we drink and offer a pharmacopoeia of potential medicines. The Pacific, Atlantic, Indian, Southern (Antarctic), and Arctic Oceans cover approximately 72% of the planet's surface.

Oceans are the habitat of, at least, 230,000 known species. The World Oceans' volume can be thought of as a cube of water with an edge length of 1,111 kilometers (690 miles). Its average depth is 3,790 meters (12,430 feet), and its maximum depth is 10,923 meters (6.787 miles).

The deepest point in the ocean is the Mariana Trench, located in the Pacific Ocean. In 1960, the Trieste successfully reached the bottom of the trench, manned by a crew of two men.

The ocean is blue because water absorbs colors in the red part of the light spectrum. Like a filter, this leaves behind colors in the blue part of the light spectrum for us to see. Nevertheless, dissolved organic matter and chlorophyll help colouring it blue.

Fact and Figures about the World Oceans:

> Life began in the ocean 3.1 billion to 3.4 billion years ago;
> Hardly any light penetrates deeper than 200 meters (656 feet), and no light penetrates deeper than 1,000 meters (3,280 feet);
> Two-thirds of all marine life remain unidentified;
> 90% of the ocean is still unmapped;
> The Earth's longest mountain range is underwater;
> 80% of sharks are unable to hurt humans;
> 50-80% of all life on Earth is in the oceans;
> 97% of the Earth's water is in the oceans;
> 90% of all volcanic activity occurs in the oceans;
> The highest tides in the world are at the Bay of Fundy;
> Pressure at the deepest point in the ocean is more than 11,318 tons/sqm (equivalent of one person trying to support 50 jumbo jets);
> The largest tsunami of all time measured 60 meters above sea level;
> The Pacific Ocean, the world's largest ocean, contains about 25,000 islands;
> If all the world's ice melted, the oceans would rise 66 meters;
> The average temperature of all ocean water is about 3.5°C (38.3°F);
> Antarctica has as much ice as the Atlantic Ocean has water;
> Three times as much rubbish is dumped into the oceans as the weight of fish caught every year;
> Blue whales are the largest animals on our planet ever;
> The Great Barrier Reef is the largest living structure on Earth;
> 39% of the US citizens live in shoreline counties;

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