The World's Oceans

Facts and information about the world's oceans

The World's Oceans

71 % Water – Less Than 10% Explored

71% of planet earth is covered in water and contains five oceans; the Arctic, Atlantic, Indian, Pacific and Southern, yet there is still very little we know about what’s under the surface. Humans have managed to explore less than 10% of the world’s oceans.

In fact, we have better maps of the planet Mars than we do of the ocean floor!

One reason for this is the immense pressure water exerts. The deeper we go, the higher the pressure due to the weight of water. This is a large hurdle to overcome when it comes to exploring the deepest parts of our oceans.

Deeper Into Diving

So how deep are the world’s oceans? The deepest spot can be found in the Western Pacific Ocean and is known as the Challenger Deep in the Mariana Trench. It was named after the British survey ship HMS Challenger which was the first to record the trench’s depth in the 1870’s.

To measure depth, the crew would lower a line with a weight attached to it until it reached the ocean floor!

The Mariana Trench lies in the middle of the ocean, near Guam. This is the deepest point in the ocean and there have only been two manned missions to reach this point.’s no simple task to reach the bottom, but with advances in technology, missions may be more frequent and allow scientists and explorers to spend more time down there.

More recent measurements have established that the depth is almost 11 kilometres below sea level. At that depth the water pressure is equivalent of having 50 jumbo jets piled on top of you.

In 1960 Jacques Piccard and Don Walsh were the first to reach the bottom of the Challenger Deep in their deep sea vessel named Trieste. It wasn’t until 2012 that a second manned expedition was sent down the Marianas Trench.

On board of the Deep Sea Challenger was the film director James Cameron, who became only the third person to reach the deepest depth of the ocean, although you might remember him more from his films such as Terminator, Titanic and Avatar.

The deepest part of the Atlantic Ocean lies in the Puerto Rico Trench at around 8,400m. On average, the oceans are about 4 kilometres deep.

You might be thinking, that’s a lot of water.

But did you know that Antarctica has as much ice as the Atlantic has water? So it’s not hard to imagine then that if all the arctic ice would melt, sea levels worldwide could rise as much as 80 metres!

This would leave a lot of densely populated areas flooded, as many of the world’s largest cities are located close to the coast.

Around The World In 1000 Years

Water takes about 1000 years to travel all the way around the globe. Known as the global ocean conveyor belt, this deep ocean current gets one of its starts in the polar region near Norway. As sea ice forms, the water left behind becomes saltier and denser and begins to sink.

The cold dense water flows along the ocean bottom all the way from the northern hemisphere to the Southern Ocean where it merges with more cold dense water from Antarctica and is swept into the Indian and Pacific Oceans. Eventually it mixes with warmer water and rises to the surface before finding its way back to the Atlantic.

It can take 1,000 years to complete this cycle. On average the temperature of the oceans is 2ºC.

Connecting Humankind Across The Globe

We as humans rely a lot on the oceans. 70% of the oxygen we breathe is produced by the oceans. We also use the ocean for a lot of transport. More than 90% of trade between countries is carried by ships and about half the communications between nations happens by use of underwater cables. With all this transport across the globe, sometimes things get lost as well.

Every year about 10,000 containers are lost at sea and in 1992 about 29,000 rubber ducks were lost at sea (which are still being found all over the world today). A man called Harold Hackett has put over 4,800 messages in bottles into the ocean and so far has gotten about 3,000 responses back.

According to the UN there are over 3 million shipwrecks on the ocean floor. So there is plenty to explore if you are a PADI Wreck Diver Specialty. The Bermuda Triangle has as many ship and plane disappearances as any other part of the ocean.

If you really want to get lost on this vast body of water that is the world’s oceans, then I can suggest a spot known as Point Nemo or ‘The Pole of Inaccessibility’. This part of the ocean farthest from land lies in the South Pacific and it happens to be 2,688 kilometres away from the nearest land.

It will be a long boat ride out there but at least it’s nowhere near the Bermuda Triangle!

The Five Oceans By Size

  • 1. Pacific – 168,723,000 km2
  • 2. Atlantic – 85,133,000 km2
  • 3. Indian – 70,560,000 km2
  • 4. Southern – 21,960,000 km2
  • 5. Artic – 15,558,000 km2

Deepest Depths

  • 1. Marianna Trench – Pacific Ocean – 35,827 ft
  • 2. Puerto Rico Trench – Atlantic Ocean 30,246 ft
  • 3. Java Trench – Indian Ocean 24,460 ft
  • 4. Southern Ocean, 23,737 ft
  • 5. Artic Basin – Artic Ocean 18,456 ft

Planet Earth Facts

  • Surface Area – 510,066,000 km2
  • Land Area – 148,647,000 km2 (29.1%)
  • Ocean Area – 335,258,000 km2
  • Total Water Area – 361,419,00 km2 (70.9%)
  • Type Of Water – 97% Salt / 3% Fresh

Author: Youri Koyen (PADI MSDT #350619)

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