Photo: BBC/Planet Earth

Down on the deep ocean floor, it's black. Really black.

Words by Oliver Berry

(First published in Stranger 13, February 2007)

And we’re not just talking about your ordinary kind of blackness either. This is black taken to the nth power. Black times infinity. Hyper-black. Googol-black. It’s so black it makes Spinal Tap’s Black Album seem spectral by comparison.

So it’s black. And cold. Ice-cold, in fact - barely a couple of degrees above freezing. It’s black, cold, and deep – deep enough in some places to sink Mt Everest with a mile to spare, creating an atmospheric pressure several hundred times greater than that at sea level. There’s no vegetation, no plant life, and very few geographical features. For most of its vast expanse, which covers over 60% of the earth’s surface, the ocean floor is essentially a flat, mud-covered plain, broken only by a range of submarine mountains called the mid-oceanic ridge and the odd cavernous trench plunging into the planet’s depths. It’s a harsh, barren world, estranged from the surface, untouched by sunlight, where life seemingly never gets the chance to gain a foothold.

At least, that was the story – but in recent years, as deep-sea submersibles and remote cameras have enabled us to delve ever deeper into the murky reaches of the deep ocean, researchers have started to uncover some of the astonishing secrets that lie in store a thousand fathoms down. “The really surprising thing about the deep sea is the sheer variety of life that not only exists down there, but actually thrives,” explains Dr Jon Copley, a deep-sea biologist at the National Oceanography Centre in Southampton. “And we’re only just beginning to scratch the surface. Every expedition reveals something new, something which expands our understanding of this amazing environment which is so close and yet we know so little about.”

Photo: BBC/Planet Earth

In terms of scientific knowledge, the deep ocean is a treasure trove just waiting to be uncovered. It’s thought that around half of the species collected by deep-sea expeditions under 3000m are previously unknown to science – compare that to the single new species of mammal to have been identified in the last thirty years, and you’ll have some idea of just how many scientific secrets are still waiting to be discovered in the deep. Even animals such as the giant squid, long rumoured to exist by mariners and scientists alike, have proved remarkably elusive – Japanese researchers only captured the first footage of a live giant squid swimming in the open ocean as recently as 2004.

Given the huge technical challenges involved, it’s hardly surprising the deep-sea environment still remains largely unexplored. “It’s a tremendously difficult environment in which to work,” says Copley. “Not only does your equipment have to cope with intense pressure, cold and lack of light, but your manoeuvrability is incredibly restricted – essentially you’re limited to seeing whatever swims in front of your lens. But as technology moves on with better batteries, cameras and remotely operated vehicles, we’re starting to uncover more and more of the mysteries of this weird and wonderful world.”

Weird and wonderful really doesn’t do it justice. Some of the creatures that inhabit the so-called “twilight zone” would make HR Giger’s more fevered imaginings look tame. Take the hairy anglerfish – a creature that’s really more mouth than fish, about the size of a beach ball, and covered with whip-like antennae designed to sense the presence of other fish in the inky darkness. Or how about the fangtooth,  owner of the largest teeth of any fish in the ocean for its size – so big, in fact, that it can’t even close its mouth. And then there’s Vampyroteuthis infernalis – the “vampire squid from hell” – which boasts the biggest eye for its body size in the animal kingdom and spits out a cloud of bioluminescent mucus when threatened. Down in the deep there are elephant-eared octopi and massive sleeper sharks, sparkling slickheads and umbrellamouth gulpers, and the deep-sea snaggletooth – a needle-toothed fiend of a fish which makes Jaws look cuddly by comparison.

But while the more outlandish denizens of the deep grab most of the attention, the vast majority of life is rather less spectacular. Take the humble nematode worm, which spends its time wriggling around the alluvial sludge at the bottom of the ocean floor. Even by worm standards, it’s not much to look at – in fact, you’d need a microscope just to see one – but it’s thought that there are more species of nematode worm than there are beetles in the rainforest. Even more intriguing are the vast colonies of creatures which exist next to areas called “hydrothermal vents”, cracks in the earth’s crust where super-heated water gushes out into the surrounding ocean. To the astonishment of scientists, life somehow manages to thrive here, living on the hot, chemical-rich fluids spewed out from deep within the earth’s interior.

“The sea floor only looks like a desert because most life is very small,” explains Dr Cris Little, from the School of Earth and Environment at Leeds University. “But these hydrothermal vents are of enormous significance to scientists. In fact, they may even help us to answer one of the great unanswered questions – how life on earth first began, and even whether it could exist on other planets.”

Little wonder, then that there has been an explosion of interest in deep-sea exploration in recent years, backed up by the groundbreaking BBC television series’ The Blue Planet and Planet Earth. There even seems to be money to be made down there – recent products ranging from sponges to sunscreen have all been inspired by creatures found in the deep ocean, and several new cancer drugs have been developed from the antibiotic properties of sedimentary animals gathered from the ocean floor.

And with a number of major new expeditions planned over the next few years, it’s an exciting time to be working in deep-sea exploration. Future projects include a £3.2m British-backed venture to study previously unexplored hydrothermal vents around the Antarctic, and several other studies investigating the effects of global warming on the deep-sea environment. “We’ve only explored a tiny fraction of the ocean floor,” adds Copley. “There’s so many unanswered questions about the life that exists down there, and it’s exciting to think that we might start to solve some of those mysteries over the next few years. There’s really no telling what we might discover.” Jules Verne would be proud.

www.noc.soton.ac.uk