Andrew Robinson
YETI CRABS & VAMPIRE SQUIDS
The Deep: The Extraordinary Creatures of the Abyss
By Claire Nouvian (University of Chicago Press 256pp £23)

When Robert Hooke published his famous folio of drawings, Micrographia, based on observations using a simple microscope and including astonishing fold-out copperplate engravings (some by Christopher Wren), the book caused a sensation and became a bestseller. Samuel Pepys bought it, sat up until 2am reading it, and noted in his diary for 1665 that it was 'the most ingenious book I ever read in my life'.

It is possible that Claire Nouvian's The Deep will have a similar impact in our time, given its perfect marriage of astounding images with ingenious science and exotic ideas. This superbly designed large-format book of photographs of deep-sea creatures, eloquently edited by a French journalist and film director, with brief and highly readable contributions from sixteen leading scientific explorers of the deep, is eye-poppingly magnificent. So much so that it provokes gasps of amazement and awe at the complexity, beauty and uniqueness of life in the abyss. One frequently finds oneself wondering whether the weird creatures floating in the darkness like visiting space aliens can really exist - except in the minds of special-effects artists (a sensation that Nouvian herself felt when she first fell for them in a documentary film in 2001). Easily in the same visual league as the BBC's series Planet Earth, The Deep provides a lot more knowledge than the television series for those who want it, without at any point overwhelming the non-biologist reader. Not so long ago, the received scientific wisdom was that the deep ocean, being eternally dark and therefore without photosynthesis, must be almost barren of life. With the underwater discoveries of the 1970s and 1980s using submersibles, scientists started to change their minds. Now, if the old myth still lingers among the general public, it will be banished forever by this pioneering book.

'With an average depth of 3,800 metres, the oceans offer 99 per cent of the space where life can develop on Earth. ... The deep sea ... occupies 85 per cent of this space, and thus forms the planet's largest habitat,' writes Nouvian in her introduction. 'And what do we know about it?' She answers: 'Compared to what remains to be discovered, practically nothing.' The naturalist Pliny the Elder believed that the marine fauna totalled 176 species. Over the last twenty-five years, a new deep-sea species (such as the hairy-pincered 'yeti crab', revealed in 2005 to much media fascination) has been described, on average, every two weeks, adding to the approximately 1.4 million known species on land, in the ocean and in the air. Current estimates of undiscovered species vary from 10 to 30 million. 'The deep sea no longer has anything to prove; it is without doubt Earth's largest reservoir of life.'

One of the major discoveries is that the depths are full of lights. There is no light from the surface, so creatures make their own. As many as 80-90 per cent of the animals collected in nets are bioluminescent - like fireflies. In fact, 'In the ocean bioluminescence is the rule rather than the exception', writes a scientist contributor. Deep-sea animals light themselves up to locate scarce food, to attract prey (like moths to a flame), to confuse predators and to signal to potential mates. The most spectacular light shows in the ocean are like burglar alarms, aiming to scare off a predator by attracting the attention of a larger predator. The vampire squid, Vampyroteuthis infernalis, a red (as hell) animal much featured in the book (and dubbed the unofficial mascot of the deep by one biologist), defends itself by spitting viscous bioluminescent clouds from the ends of its arms, which can glow for up to ten minutes while the squid makes its getaway. It also protects itself by being able to survive in deep water (between 650 and at least 1,500 metres) that has too little oxygen for its predators, using a respiratory blood pigment able to extract oxygen with unusual efficiency - a capacity this 'living fossil' appears to have evolved more than 200 million years ago.

One photograph of the vampire squid shows its mantle unfurled in a typical umbrella posture, while on its head it appears to be wearing a sort of Father Christmas hood with two flapping ears. It is bizarrely appealing - like dozens of other creatures in this book. For instance, the so-called dumbo octopus: only twenty centimetres in height with no tentacles, two small ears and what appears to be a tiny lolling tongue, it is found as deep as 5,000 metres. Fourteen species of this octopus are known but its behaviour remains enigmatic. Dumbo octopodes are often observed resting on the bottom, surrounded by their mantle. 'What are they doing there, sitting so quietly in the dark? Nobody knows.'

In due course, Claire Nouvian writes modestly at the end of her lovely and fascinating book, the deep sea will have become so accessible to tourists that the book will seem 'obsolete'. Certainly the science will date but I wonder if the book will. The Deep deserves to become a modern classic of natural history.