Seven-Tenths Read online

  This neat theory of Darwin’s was contested, notably by the Scottish oceanographer John Murray. After the sudden death in 1882 of Charles Wyville Thomson, who had led the Challenger expedition in the 1870s, Murray took over the job of publishing the expedition’s immense report. He had been on the Challenger himself and was very struck by the sediment samples which revealed far greater precipitation than he had imagined. He now thought Darwin’s theory too complicated and too dependent on crustal movement. Instead, he proposed that the calcareous remains of plankton, falling on undersea mountains in a steady drizzle over the millennia, built up a layer of compacted sediment reaching to within 200 feet of the surface, at which point the coral larvae started their colonies. In order to explain the atoll’s characteristic shape Murray somewhat weakly suggested that this was simply the normal pattern of growth for coral colonies. Trees grew into tree shapes, corals into atolls.

  In order to settle the dispute, scientists visited the Great Barrier Reef and the Maldives (where the word ‘atoll’ came from) at about the turn of the century, but the results of their researches were inconclusive. It was obviously going to be necessary to bore straight down into a reef and take core samples. If these turned out to consist of dead coral, Darwin would be vindicated; if it was sediment, Murray. HMS Penguin (without Boyle Somerville on board) sank some holes and the findings seemed to support Darwin, but they were challenged by champions of Murray’s theory who claimed the results were false because coral fragments had fallen down the borehole as it was being dug.

  The problem was not finally solved until after the defeat of Japan in 1945. Suddenly the United States found itself in possession of hundreds of scattered coral islands and atolls which had formerly belonged to the Japanese Mandate. Needing somewhere isolated to test nuclear weapons, the US searched its new trust territories and hit upon the Marshall Islands. At that point a serious investigation was made of the underlying geology, in the course of which scientists took core samples from deep borings. In Eniwetok and Bikini atolls they went down to over 4,000 feet and found it to be solid coral all the way to the basaltic bedrock, interspersed with strata containing the fossils of land snails and pollen which showed that the island’s generally downward progress had been interrupted from time to time by violent upheavals which had brought it back above sea level for a few millennia. Darwin’s theory was essentially, if belatedly, proved correct.

  Since then it has become clear that many reefs (including the Great Barrier) are formed in ways rather more complicated than Darwin’s simple schema. In 1919 the American geologist Reginald Daly proposed that glaciation during ice ages would have had just as much effect on corals in terms of their growth and erosion as geological sinking. Current anxiety over global warming and the projected rise in sea levels has revived Daly’s ideas, and in places like the Maldives it should soon become apparent to what extent changes in sea level mediate the formation of coral reefs.

  *

  The centuries-long dispute about the nature of coral is rendered neither obsolete nor irrelevant by modern science. True, there is no longer any doubt about the organisms responsible for reef building and – broadly – how they do it. At levels of biochemical detail, however, there is still much to learn. Most reef-building corals, for example, exist in symbiosis with microscopic algae. A single coral polyp looks very like a miniature anemone, its close relative. It has rings of stinging tentacles surrounding a mouth, all of which is able to contract defensively into its stalk. Living within its tissues are the algae which among other things perform photosynthesis and fix nutrients for their host. More than that, the algae enable the polyp to secrete stone. This is a most remarkable attribute and brings a certain accuracy to the old name ‘madrepore’. Since algae able to photosynthesise are considered plants there arises the peculiar arrangement whereby a plant and an animal combine to produce a mineral – in this case pure limestone. The chemistry by which this is done is not yet entirely understood. There is great complexity in the way these symbionts interact both with each other and with the nutrients in the seawater, with varying temperature, degrees of salinity (fresh water is fatal to corals, which is why fringing reefs are always broken at river mouths), with currents and with light. Not the least striking part of a coral reef’s equivocation, therefore, is that it imprisons at its heart a gigantic plant, while on its surface and slopes there may be few marine plants visible since herbivores such as surgeon fish and sea urchins constantly graze seaweeds back to their roots.

  The swimmer among reefs likes to know such things, likes to shine torches into cracks and crevices, takes pleasure in seeing a tube worm sense his presence (smell? sound? shadow?) and retract in a flash, takes pleasure also in knowing the worm ate its tunnel into the coral limestone by secreting acid. It is not only in details that we experience reefs, though, any more than we experience a forest by examining leaves and marvelling at processes of gas exchange. Both reefs and forests may be studied closely but are experienced as environments. So viewed, coral reefs are true borderlands, abounding in all sorts of ambiguity. Many of these ambiguities are set up by the classificatory systems which have been used to make sense of phenomena that refuse their assigned niches. The swimmer who daily goes down among corals to watch and listen soon becomes aware of something in this rich profusion which corresponds to the so-called ‘dark matter’ postulated by astronomers to account for there not being enough visible matter in the universe to satisfy theory. (In this sense ‘dark matter’ can be viewed as the astronomical equivalent of the vanishing islands of the North Atlantic.) The ‘dark matter’ in reefs is the subject of the second part of this chapter; it is enough for now to point out that any form of classification, merely by drawing an imaginary border between two groups of objects, spurts into sudden being a third space as real as the counterbalanced pole which marks the frontier between two countries but is not in either one. Merely to propose that A is not B automatically brings a third coordinate into play, the offspring of wherever it is one stands in order to dispense categories, and which partakes of both A and B. All liminalities belong entirely to the mind, and we are perverse if we expect the objective world to keep to our categories.

  At the moment the whole corpus of Linnaean taxonomy is in dispute as radically new ways of grouping creatures are proposed. The way we view the natural world is unconsciously influenced by our received picture of a stylised evolutionary tree which over the past 200 years has become steadily more ramous and bushy as efforts are made to graft fresh discoveries on to the existing trunk and limbs. Changing this schema would have an interesting effect. There is no serious question that some form of Darwinism is the best model we have of how things evolve, but there is much doubt about traditional notions of the relationships between them. Modern taxonomy has to confront the possibility that the hypothesis of ‘Mitochondrial Eve’, the putative mother of the entire human race, may eventually become elevated to a theory by advances in genetics. The category of species, the lowest classification of all, is under constant pressure not only from modern fieldwork but from palaeontological evidence like that of the Burgess Shale.* Maybe coral polyps will one day find themselves in an entirely new category (or back in an old one) of plant-animals, now based on something like ways of dealing with nitrogen.

  Vladimir Nabokov, who was once simultaneously the Curator of Lepidoptera at Harvard and Professor of Literature at Cornell, said of writing that ‘the precision of the artist should accompany the passion of the scientist’. This is an admirable recipe for swimming among reefs, where details must be avidly noticed but never seen in isolation. Modern entomology no longer distinguishes between moths and butterflies (Nabokov’s particular interest), the classification having been deemed too arbitrary to be meaningful. All those Victorian clergymen, earnestly sorting knobbed antennae from feathered antennae and mildly put out to discover day-flying moths, were making distinctions which have turned out not to be taxonomically useful after all; except that no discrimination is
ever wasted in either science or art since all interest derives ultimately from the ability to spot difference.

  *

  A reef project (how full the world is of reef projects!) was under way a few years ago off the coast of Kuyo Island. At the time I was living on an islet in the same group. On a visit to town I met Jim Parkes, who had until recently been a Peace Corps volunteer, had since gone away and returned with a technical qualification and was now seconded to the Bureau of Fisheries. He took me some miles to a dismal scene. Offshore was a typical fringing reef which at low tide became a flat, extending maybe 200 metres to a white line of surf. Ordinarily it would have been an expanse of puddles and small pools at low tide, dotted with boulders and slimy with liver-coloured blobs of this and that. One would have expected to see groups of villagers, mainly children, with tins and plastic bags, going through the tidal pools for edibles: shells, baby octopus, blennies and gobies. Instead, the reef was a destruction site. A new causeway of blinding white coral chips led out to the middle where a yellow excavator stood up to its axles in seawater, fanged bucket plunging and rising, disgorging a rubble of water and corals into the back of a truck.

  ‘We’ve got a problem here,’ said Jim. Up to then I had not especially liked him but was now won over by this unsuspected laconic talent, for the scene was one of ruin made ironic by its backdrop of a tour operator’s tropical idyll. A long white beach stretched in a curve backed by coco palms, all done in the three primary colours of holiday brochures (blue sea, white sand, green fronds) whose baldness in print never hints at the possibility of considerable subtlety. ‘What we’ve got is a company mining coral for construction and a fishing community without any fish. And a mayor up for re-election.’

  The coral had been mined here for some years before the heavy machinery came. Men with crowbars had levered out chunks which buffalo hauled away on crude sleds. Coral could be crushed and spread as a gravel bed for roads, or roughly dressed could be used for building in place of the ubiquitous hollow blocks. ‘Labour’s cheap, cement costs,’ as Jim remarked. ‘Now, the gentleman who owns the rig and the truck is a local who sort of inherited them from a government project to build a road around the island. That failed from lack of funds and equipment, largely because they were all embezzled or stolen in the first month. I’ve got this congressman friend in Manila who has his own reasons for not wanting the beaches of this island ruined. … No, you don’t want to know about it, believe me. … So although he doesn’t realise it yet, within a week or two this guy with the ’dozer’s going to get zapped by Presidential Decree number twenty-eight thousand three hundred and eleventy-six which forbids the destruction of the foreshore owing to the fact that it’s national property. Problem is, what to do with the remains.’

  About half a mile of immediate reef had been destroyed, the topmost 4 feet having been stripped out. One consequence was that the corals on the surviving outer slope were visibly suffering since the outgoing tide was now bringing with it none of the nutrients and planktonic matter generated by corals inshore. Jim and I swam up the reef and he showed me a further effect of the excavations. There were powerful currents on this coast, in some places running almost parallel to it. Lowering this reef flat by a mere 4 feet had caused a neighbouring bay to be scoured of its sand which the current was dumping over adjoining reefs, smothering them. Local fishermen had been driven on to reefs further along the coast, leading to friction with those already there, to overfishing and the increasing use of dynamite in an attempt to make up for smaller catches. This in turn destroyed corals which led. …

  ‘You get the picture,’ said Jim. ‘It’s bad wherever it happens but they’re doing this sort of thing even in the Maldives, which has to be cutting their own throats. The highest point in that country’s about 2 metres above sea level, and since it’s all coral there’s nothing else to use for building. Probably the best thing there would be to earmark an entire atoll for excavation and ban it everywhere else. As it is, when you remove coral piecemeal, like here, it’s hard to see the end of the knock-on effect. Last week a fisherman was killed about 5 miles down the coast. Dynamite. Got the fuse wrong, took off his arm and half his head. OK, you can say that was his fault, it was his choice to go fooling about with gin bottles packed tight with fertiliser. On the other hand you could say he might never have done it if it hadn’t been for this thieving dickhead here.’

  Our swim had revealed something else about the surviving corals on the seaward slope, which was that they were showing the first signs of bleaching. This is a condition which happens when the polyps eject their symbiotic algae. Since it is the algae which give polyps their colour (true corals produce pure limestone, which is white) the corals blanch, the polyps becoming no more than a milky slime on their surface. It is not yet known why bleaching occurs, only that it is probably a sign of stress. There may be no unitary cause. The polyps can recover spontaneously or die, in which case the corals often turn green as their skeletons are colonised by ordinary algae. It is unsettling to swim along a reef slope and see among the profusion of coral species the bone-white beginnings of blight, a marine leprosy mysterious and as yet patchy. It conveys only that something is wrong and likely to become worse, that everything is more poised on an edge than one knows.

  A few days later I was in the middle of the small island, inside the belt of coconuts and among the paddies and fields of peanuts. Behind the last plantations rose an abrupt low cliff of dark grey rock from which grew creepers and swags of greenery, an escarpment topped with uneven patches of forest. It was evidently from this miniature lost world that each evening the great fruit-eating bats flew out, many of them spanning more than a metre, to descend on the cultivated coastal belt. There they fed on papayas and drank the palm sap being tapped to make toddy. The cliff was no more than 100 feet high, generally less, and was made of fossil coral. Everywhere were the regular patterns of polyp colonies, the dimplings, pores and stars of tiny stone-secreting animals whose labour had built entire islands as well as the Great Barrier Reef, the biggest single structure on Earth. At some time in the past the flat top of this island where I stood among the tamarinds and cashews had lain beneath a shallow sea rippled with sunlight and thronged with blue devils and fuseliers like chips of sapphire. Having sunk and then risen it was presumably now sinking once more. It was difficult to make sense of such geological eras because the inconceivable slabs of time could briefly be prised apart and wedged open by rudimentary arithmetic. If corals could grow at the rate of an inch a year, which under optimum conditions they can, then this entire escarpment might only have taken 1,200 years to lay down – say from the time of Beowulf to the present. A mere nothing, really.

  Why, then, could it not be dismantled again? If people needed building materials it made more sense to break up dead coral deposits than to destroy live reefs supporting a complex local ecology which included many hundreds of villagers. I put this point to Jim but he said fossil coral was far harder than recently formed limestone. The outside might appear friable, but that was just weathering; inside it was like granite. I did not know if this was true. At any rate the idea came to nothing and one was left with the sense of a gross imbalance. It seemed abysmally crude to smash up a construction of microscopic architecture in order to build other structures of a coarseness grotesque in comparison. What, then, was Jim’s ‘project’ if not merely to stop the mining of coral?

  ‘Re-establishing fish, naturally,’ he said. ‘Or unnaturally.’

  The best thing to do was simply to leave the hacked substrate alone for a century or two, by which time and with any luck new corals would have established themselves. Sure, said Jim, the best thing so long as you had an alternative source of food. Hadn’t I got the idea yet? This business wasn’t particularly to do with corals, it was to do with fish and, eventually, with votes. If I tried thinking of the fishermen as farmers, then these reefs were their fields. Plough up a field without re-sowing it and you’d get nothing but a crop of weed
s.

  I supposed so. The truth is, remedial work bores me. If one is a fatalist one believes that once something needs to be restored, to be caught and fought for on the edge of extinction, then in a sense it is already gone, has already been lost in the form that had meaning. It is a pleasing irony that any revivalism, like life support, always suggests demise and not survival. Why should this be? And does it mean that someone who recovers after terrible injuries and weeks of intensive care is no longer authentic? At any rate, Jim’s solution was to create an artificial reef out of old truck tyres. He was going to take delivery any day now of several hundred tons and dump them all over the ruined reef. It was, he said, an experiment which would be watched closely in many parts of the world. If it worked it would solve two major problems at once, since up to now nobody had found any use for old tyres except maybe as fenders on wharves. Tyres would make terrific habitats for reef fish because if dumped higgledy-piggledy they formed an elaborate honeycomb of holes and crannies for shelter. After a time they would become encrusted with marine growths and maybe eventually even corals would take root and start building. In the meantime they would be colonised by fish.