13 fascinating facts about the world’s oceans
<p><strong>The reason it’s blue</strong></p>
<p>The ‘deep blue sea’ – and our ‘blue planet’ along with it! – owe their iconic colour to the light of the sun. When the sun shines on the ocean, the water absorbs the longer red and orange wavelengths of light while reflecting blue light back. This will only happen, though, with a large amount of water; the more water you have, the bluer it is. This is why the water you drink out of a glass doesn’t appear ocean-blue. This process of light absorption and reflection is also the reason the sky is blue – but the blue colour of the ocean is not because it’s reflecting the colour of the sky, as many people believe.</p>
<p><strong>The ocean is full of gold</strong></p>
<p>The phrase ‘liquid gold’ was never so applicable. Believe it or not, every drop of ocean water contains a teeny-tiny bit of real gold. It’s such an inconsequential amount that you’re not going to get rich by scooping up seawater – there are about 13 billionths of a gram of gold in every litre of seawater. But when you consider just how much ocean water there is on the entire planet, that does add up to a lot of gold. About 20 million tonnes of it, to be specific! Considering that that amount would be worth hundreds of trillions of dollars, the ocean’s hidden gold is truly an unattainable fortune.</p>
<p><strong>It comprises 99 per cent of the planet’s habitable space</strong></p>
<p>Wait, what happened to only 70 per cent? Well, there’s a difference between the amount of the Earth’s surface covered by ocean (that’s 70 per cent) and the total amount of space. With the depths of the oceans taken into account, the ocean comprises a whopping 99 per cent of all habitable space on the planet. Despite all that open space, though, the ocean isn’t as populated as the land is, in part because the deepest parts of the ocean are inhospitable to all but a few life forms.</p>
<p><strong>Someone once free dived 253 metres into the ocean</strong></p>
<p>Compared to the actual deepest point of the ocean (the Mariana Trench stretches down nearly 11 kilometres), 253 metres may not seem that deep. But when you consider that this intrepid diver was accompanied only by a wetsuit, a weighted sled and an air balloon to help him float back to the top – without even scuba gear – his accomplishment seems a lot more noteworthy. It’s the deepest part of the ocean ever reached by a free-diving human (as opposed to a human inside a machine). The diver, Herbert Nitsch, completed his historic feat in 2012, and he currently holds 33 separate world records in free diving. Through rigorous training, he’s been able to increase his lung capacity to more than twice the usual amount of air.</p>
<p><strong>The pressure at the bottom of the ocean is extreme…</strong></p>
<p>…it’s like being-crushed-under-a-pile-of-elephants extreme. At the bottom of the Mariana Trench, the pressure is about eight tonnes per 6.5 square centimetres, the equivalent of about 100 fully grown elephants. It’s so intense that, while we do have machines capable of withstanding it, equipment has simply imploded under that amount of pressure.</p>
<p><strong>It helps power the internet</strong></p>
<p>The next time you’re watching a funny cat video or enjoying a Netflix binge, make sure you thank the ocean. The vast majority of the cables that power the internet, allowing access to it across the entire globe, are underwater. Wires called ‘submarine communications cables’ crisscross the ocean floors and were put in place by boats built solely for that purpose. To ensure that the cables remain undisturbed, they have to be placed on relatively flat stretches of the ocean floor, away from ocean ecosystems or shipwrecks. Some of the cables even have a coating that protects them from being damaged, should a hungry shark come across them.</p>
<p><strong>The biggest waterfall in the world is underwater…</strong></p>
<p>It might seem counter-intuitive to think that there are bodies of water within the oceans, but it’s true! Deep within the ocean, caverns and fissures on the ocean floor form when water oozes through the layers of salt beneath it. This water, filled with dissolved salt, is denser than the water around it and settles into the fissures. It’s this type of dense water that forms the Denmark Strait, a massive cascade of water that plummets 3500 metres. This is because the colder water of the strait sinks when it collides with the less dense water around it.</p>
<p><strong>…and so is the world’s tallest mountain (partly, at least)</strong></p>
<p>With 70 per cent of Earth’s surface covered by oceans, it makes sense. But that doesn’t make it any less mind-boggling to learn that in Hawaii, there is a mountain that would make Mount Everest look like a bunny hill if they were side-by-side. Mauna Kea is half under the water and half above it, and, from top to bottom, it stretches a whopping 10,000 metres. That’s more than a kilometre taller than Mount Everest! We consider Mount Everest the tallest mountain because it reaches the highest distance above sea level, but in terms of height from top to bottom, this half-submerged Hawaiian volcano is the champion.</p>
<p><strong>There’s a spot in the Pacific where you’re closer to space than anywhere on Earth</strong></p>
<p>This unique spot, the furthest on the entire planet from land, goes by the name ‘the oceanic pole of inaccessibility’, or, more concisely, ‘Point Nemo’. We know what you’re thinking – its name does not come from a cartoon fish but from the hero of 20,000 Leagues Under the Sea. It’s located smack in the southern Pacific Ocean, and you’d have to travel 1600 kilometres from even the closest points of land to reach it. Those points of land are Motu Nui, far off the western coast of Chile; Ducie Island, one of the Pitcairn Islands between South America and Australia; and Maher Island, off the coast of Antarctica. And it’s at least 1600 kilometres from each of them. That’s so far that the closest people to Point Nemo are often up in space! The International Space Station orbits just 400 kilometres above Earth’s surface. Now that gives ‘finding Nemo’ a whole new meaning.</p>
<p><strong>Most of Earth’s oxygen comes from the oceans</strong></p>
<p>And no, it’s not the ‘O’ of H2O. When it comes to ocean facts, most people don’t know about 70 per cent of our planet’s entire supply of oxygen is a waste product created by marine-dwelling plankton. These minuscule creatures take in carbon dioxide and produce oxygen during photosynthesis, and this oxygen plays a vital role in the life of every oxygen-breathing creature on the planet. According to National Geographic, one type of plankton called Prochlorococcus produces so much oxygen that it’s most likely responsible for one of every five breaths we take.</p>
<p><strong>No one knows for sure what made this mysterious undersea noise</strong></p>
<p>In 1997, the National Oceanic and Atmospheric Administration detected a mysterious undersea sound – incredibly loud and at a very low frequency – and puzzled for years over its origin. <a href="https://www.youtube.com/watch?v=ZA2wY5-yiGY">Take a listen here</a>. It may sound a little bit like your stomach when you’re hungry, but scientists have theorised that everything from a massive marine animal to a shifting iceberg is responsible. Icebergs cracking and shifting on the ocean floor produce a similar sound, so that’s the most likely explanation, but there’s no definite answer yet as to what it is.</p>
<p><strong>A rubber duck accident helped researchers understand ocean currents</strong></p>
<p>We’re used to ‘spills’ in the ocean having disastrous effects, but this one proved to be something of a happy accident. In 1992, a crate of bath toys on its way from China to the United States broke, spilling thousands of rubber ducks and other floating toys into the Pacific. Oceanographers seized the opportunity to learn more about the movements of the ocean. Oceanographer Curtis Ebbesmeyer headed up the research efforts, asking beachgoers all over the world to report sightings of the ducks and their floating friends. The ducks travelled far and wide, ending up everywhere from Europe to Alaska to Hawaii and continuing to be spotted well into the 2000s. The fleet of toys became affectionately known as ‘the Friendly Floatees’.</p>
<p><strong>Antarctic-dwelling fish have a protein that keeps them from freezing</strong></p>
<p>Unsurprisingly, the water around the poles can get pretty chilly. Yet there are still plenty of fish that make their home there. A group of fish called notothenioidei comprises over 120 species all native to the Southern Ocean near Antarctica. The water in that area hovers around temperatures of -2° and 10° Celsius. Even when it’s technically below freezing, the dissolved salts in the seawater keep it from doing so. But how does marine life possibly stay alive there? Well, these fish have a biological component called a glycoprotein that allows them to live where they do; it acts as a natural antifreeze, essentially. The protein prevents ice crystals from forming in their blood, allowing it to flow normally.</p>
<p><em><span id="docs-internal-guid-9a6d26fe-7fff-aeac-06e5-045b3fd355a8">Written by Meghan Jones. This article first appeared in <a href="https://www.readersdigest.com.au/true-stories-lifestyle/science-technology/13-fascinating-facts-about-the-worlds-oceans" target="_blank" rel="noopener">Reader’s Digest</a>. For more of what you love from the world’s best-loved magazine, <a href="http://readersdigest.innovations.com.au/c/readersdigestemailsubscribe?utm_source=over60&utm_medium=articles&utm_campaign=RDSUB&keycode=WRA87V" target="_blank" rel="noopener">here’s our best subscription offer.</a></span></em></p>
<p><em>Image: Getty Images</em></p>
