Leave the deep alone: We depend on the ocean more than we realise

If you gaze too long into an abyss, warned Nietzsche, the abyss will gaze back into you. And indeed it will, with a very weird face, or lack of one: perhaps a luminous ctenophore (or comb jelly), looking like an extraterrestrial spaceship with glowing tentacles extended, or a red vampire squid, webbed fingers ready to grasp..Nietzsche, after all, reckoned without the advances in technology that enable marine biologists such as Helen Scales to observe the vasty deep by means of camera-equipped remote-control submarines, from the relative safety of a boat high above. So recently has this become possible, indeed, that we know more about the surface of the Moon than we do about the ocean floor – which, moreover, covers an area 10 times bigger..The depths are where, in cultural imagination, monsters lurk: from the Kraken to Godzilla. The "twilight zone" is where light from the surface begins to die out; the word "abyss" itself is Greek for "bottomless void" or "pit of hell"; and the scientific name for the very deepest parts of the ocean trenches, up to 11km down, is the "Hadal zone", named after the mythological being of the underworld..Down there, it was believed that most of the ocean was "azoic": bereft of animal life. Now it turns out that it is all biosphere, and indeed that life might even have begun in the deep, around hot hydrothermal vents, where seawater that has leaked down through the Earth’s crust and been heated to beyond boiling point by the Earth’s magma erupts back into the ocean. Microbes discovered down there can survive being baked in an oven at 121 degrees celsius.. The book also has a crusading message: we are harming ourselves the more we harm the ocean Image Credit: Supplied .It is, indeed, weirdness all the way down, and Scales’s bestiary, The Brilliant Abyss, is a wonderful introduction to its variety, from the relatively familiar sperm whale, which can hunt a kilometre deep, to the worms that feed on its bones once they have fallen to the ocean floor, known – of course – as "bone-eating zombie worms". We are also introduced to ultra-black deep-sea fish, cyborg snails that make their shells from iron, carnivorous sponges, and Yeti crabs that have furry claws: "Tipped with a pair of goofy-looking, rounded pincers," the author explains, "these pelts of blonde fur give the animal the look of a deep-sea crab that might appear on The Muppet Show.And that’s not to mention the three species of glow-in-the-dark sharks discovered since this book was written..Scales’s enthusiasm for her subject is matched by a gift for visual evocation, often disgusting. ("Picture," she commands the reader, "a close relative of the woodlouse that hides under rocks or garden pots, but pale pink and the size of a rugby ball." I’d rather not.) She is very good on the mountainous topography of the seabed, and the unimaginable forces that operate on its denizens. Once you are at a depth of 8km, she explains, where snailfish can live, the pressure exerted by all that seawater above is equivalent to "an elephant standing on every few square centimetres of your body"..The book also has a crusading message, which is that we depend on the ocean more than we realise, and are harming ourselves the more we harm it..The ocean itself acts as a huge heatsink, without which the planet would be already unlivably scorching..Like the threatened rainforests of the Amazon, too, the ocean is a vast store of biodiversity, which our self-interest ought to ensure we manage well. Powerful anti-cancer drugs have been derived from sea sponges, and many more promising "bioactive molecules" have been identified in ocean-dwellers, some of which might also help us fight the pressing problem of antibiotic resistance..Scales’s plea to leave the deep alone – apart, of course, from the friendly bathyspheres of marine biologists and the humane explorations of researchers – is a persuasive and edifying one. Who can be absolutely sure that no monsters slumber down there after all?.Read more. How cigarette butts are ruining our oceans Top 10 Pacific adventures In a place where dragons lurk, an adventure in search of Offa’s Dyke