Here be sundry marvels
David Profumo
MAPPING THE DEEP: THE EXTRAORDINARY STORY OF OCEAN SCIENCE by Robert Kunzig
Sort of Books, £8.99, pp. 345, ISBN 0953522715
Although I spend much of my life afloat, even as an avid angler my knowledge of the sea is partial, confined to those relative shallows where the piscifauna can be tempted with rod and line. Only once have I descended in a submarine, and that was a tawdry tourist affair in the Caribbean — the submersible equivalent of some rum cruise on a fake pirate sloop — undergone specifically so that I could brag in a newspaper column that there were no depths to which I would not go to get a story.
The story in Mapping the Deep begins and ends with the stars. Robert Kunzig rehearses various ideas about how water first appeared on Earth (was it comet snow, or volcanic outgassing?) and stresses how slow we have been to explore its depths; as recently as 1950, only two men had ever survived going deeper than sunlight, and whereas we can now discern the contours of Venus through its dense atmosphere of sulphuric acid, only ten per cent of our own seafloor has been comparably surveyed. It is the history of this attempt, rather than some wacky world of giant squid and blind fish, that his book so quirkily addresses.
Those pioneers were an intrepid lot, with their plumblines and nets. There was longhaired Manxman Edward Forbes, a Victorian poetaster with a passion for dredging ('Hurrah for the dredge, with its iron edge'), and the American Graf von Rumford (not a very nice man') who invented soup croutons before discovering convection currents. Oceanographic measurement continued to be an inexact science until quite recently: on one research vessel just after the last war, the 'fathometer' registered a bottomless abyss whenever someone opened the ship's fridge.
Although it seems the entire ocean floor will never be mapped — it would take even a high-tech ship two centuries — the evolution of submarine cartography has been boosted by geosat (a device that deduces topography from gravitational variations) and multibeam sonar, so that gradually ideas about seafloor spreading and fracture zones have emerged. But the first real coherence was given to these geological conundrums in 1967, when Jason Morgan propounded his theory of plate tectonics, which offered a dynamic view of the earth's changing complexion, with the oceans as the driving force. As every schoolboy now knows, the seafloor is not flat, but punctuated with volcanic cones, sea-mounts and abyssal hills.
My mediaeval grasp of natural science may have failed to master thermohaline circulation or planetary vorticity, but Kunzig's overall plotline remains clear, not least because his book reads, fittingly enough, like some detective story. In particular, deep-sea biology has entered a new era as the life of marine trenches is revealed. Here be sundry marvels; on the slopes of sunken volcanoes thrive echiuran worms with tongues a foot and a half long, and there is a whole kingdom of leathery sea cucumbers ('Most holothurians breathe through their anus'): presumably they are the elected representatives of these tenebrous zones. Baited cameras attract unnerving scavengers like hagfish and porcelain white crabs. Given this biological diversity, the analogy should be with the rainforest rather than outer space.
The earthquake area off the Galapagos islands provides a locus classicus for these studies, for here hydrothermal eruptions have actually been observed (one such site is jauntily dubbed Tube-Worm Barbecue). Witnessing the boiling spectacle, with its 'black smoker' hot springs, Rachel Hayrnon reports, 'Everybody was jazzed.' This volcanic saga epitomises the dramatic state of flux in the submarine world, and some researchers now believe these seafloor hotsprings may have been where life began. Elsewhere, the cast of Kunzig's drama includes wing-footed snails, 25-gallon jellyfish, and a dinoflagellate that preys on fish 10,000 times its size — truly, a chronicle of trench warfare.
Even when necessarily technical, the prose is not too clogged with formulae or Latinisrns, and the lay reader is whisked through the tale by agreeable currents of evocation (cod fall on a shoal of capelin, 'like fighter planes coming out of the sun — their mottled skin camouflaging them against the gravelled ground') and the author's penchant for anecdote. For the book is in part a tribute to strange scientific devotions, Gerard Bond, who searches for evidence of past climates by analysing the sedimentary record, examines sand-grains individually under a microscope, and reckons he has personally sorted some 700,000; his conclusion is, `No geologist in his right mind would ever do anything like this.' Well, I was jazzed.
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