‘What’s it like? The big blue?’
‘Ummm, big and blue.’
‘…I knew it!’
It’s one of many amusing lines that finds itself integrated within the script of that fantastic film that is ‘Finding Nemo.’ Although not particularly scientific in it’s description, it was of course correct, the oceans are indeed rather big and rather blue. Those are two things about our oceans that we do know for certain, but these raging waters are one, if not the most unexplored habitat on Earth. As we know, we have five oceans: The Atlantic, The Pacific, The Indian, The Southern and The Arctic. In total, these five masses of water cover around 335,258,000 sq km! That’s a lot of ocean to explore, and I suppose we could be forgiven for not managing to explore it all. After all, unlike many sea creatures who are perfectly adapted to life underwater, us humans just can’t manage without the aid of technology. Pressure changes make it very difficult for us indeed, with the deepest sections of our oceans putting an amount of pressure on the human body that is equivalent to 50 jumbo jets! As an oceanographer, my father often goes away on research cruises. For a bit of fun, they used to attach a foot tall Kenny doll (from southpark) to a CTD rosette (used to measure conductivity, temperature, depth and much more). When the CTD was brought back from the depths, such was the pressure, poor Kenny would have shrunk in size to be about an inch tall, and would slowly regain his normal size throughout the day (you have to find some way to amuse yourself out at sea).
So, on the surface, we know, or think we know, quite a bit about these ocean habitats. We know about gaseous exchange, we know about changing salinities, ocean warming and expansion, tides, ocean trenches, water types and of course, we know about our marine life. Or do we? Now, you would have a fair argument if you were to say, yes actually, we do! We know we have a plethora of marine species, from the microscopic phytoplankton to the giant blue whale, so we could claim that we have a fair idea about the species that exist in our oceans. But when around 95% of the oceans and 99% of our ocean floors remain unexplored, do we really have a handle on our Earths marine life?
In the deepest, darkest areas of our oceans, the colour of the water is black and the animals that live there are more than mysterious. So, what’s down there? What creatures do we know about? Well, admittedly, we do know a fair few and I am not about to reel them all off (phew), but just give a few of the more bizarre and therefore fascinating specimens. The frilled shark for example, a species that, although it lives thousands of feet below the surface in the Atlantic and Pacific Oceans (we think), has been seen by some people on those rare occasions when they come closer to the surface. However, usually, human experiences with this species occur when their bodies wash up or are discovered in deep sea trawler nets.
Another creature that I am sure many of us are familiar with and has spawned a few monster movies, is the giant squid. Giant indeed, with the females of the species being known to grow up to around 13m in length and the males around 10m. So far, we are only aware of the existence of one species of giant squid, but there is always the possibility of more. Although descriptions and references of the giant squid go as far back as Pliny the Elder and Aristotle, the first photograph of a giant squid in its natural habitat was not taken until 2004! But the giant squid is not the only giant of the deep. The megamouth shark, for example. Known to remain at around 150m below the surface during the day, this shark does rise closer to the surface at night. The megamouth shark is thought to be extremely rare (though we can’t be sure) and was only discovered in 1976 and since then, very few specimens have been observed or recorded.
Seems like a lot of sharks are down there right? Well, get ready for one more. The goblin shark. Described as a ‘living fossil’, they have pink skin, extendable jaws for catching prey and a lineage that goes back almost 125 million years! Despite this impressive ancestral history, the goblin shark was only discovered in Japan in 1898. Like all goblins, the goblin shark lives and hunts in the dark, inhabiting depths of around 100m, possibly deeper. So, 100m, 150m, impressive? Well, compared to some species of fish, 150m below the surface is nothing! The viper fish, which is around 1 foot in length, can live in waters of up to 5000m deep! In fact, the home of the viper fish is so deep that relatively little is known about him, with most of those individuals that are seen being caught by deep sea trawlers. However, the viper fish has a rival. The fangtooth fish. The fangtooth is one of the deepest living creatures ever discovered in the oceans, being found even deeper than 5000m below the sea surface. The fangtooth fish is not keen on light, so the murky sea floor is the perfect habitat, with the fangtooth only venturing to shallower depths during the night.
But these species are merely a taster of the fascinating creatures that inhabit the oceans floors and depths. There are many more that we know about and even more that we are unaware of and yet to discover. The floors of our oceans are mysterious and although we have managed to venture down to some of the oceans deepest depths, such as the Charlie-Gibbs Fracture Zone in the Atlantic, and although new species are regularly discovered, we would have to hang around for quite some time before we were to find even a fraction of all the species that lurk there.
Next time your looking down below your feet as you swim, driving along the coast or fly over the oceans, take a moment to imagine the species that rule the depths. Just think, if species as large as the megamouth and the giant squid can be so elusive and remain unseen and undiscovered for so long, imagine what other creatures await us!
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