Authors: Iain McCalman
Our work was never finished. All day, and not infrequently, all or part of the night, it continued. Work of such intensity in such a climate was hard; I felt perpetually tired; every action demanded a tremendous initial effort … It was not until I left the island that I realized fully under what a strain we had been living for many months past. At the same time it was work that made life endurable: without that compelling interest the continuous association of so many people in such an environment would have been impossible.
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Neither was the situation of the Aboriginal workers quite as idyllic as it had initially seemed. Gracie proved to have a quick temper, and she chose to leave the island after four months. Andy, in the meantime, had apparently done little but stand motionless, staring at the water with fish spear raised. Yonge probably didn’t notice that he was unwell—he died within a few months of departing the island.
However, the replacements from Yarrabah mission, Minnie and Claude Connolly, and their children Teresa and Stanley, were a greater success. Minnie did all the cooking and washing without complaint. Claude, though elderly and lame, delighted everyone. A former tracker who’d been wounded in a shoot-out with the Kelly gang in Victoria, he never hesitated to take on any challenge. When not working, he carved gifts for the scientists of firesticks, spears, and model canoes, and he loved polishing pearl shells on a grinding wheel to give to them. Maurice Yonge thought him “an honour to his race” and “a living refutation of the slanders from which the Australian aboriginal has so long suffered.”
Yonge also praised the expert contributions of the two Yarrabah boatmen, Harry Mossman and Paul Sexton—“good servants to the expedition … and to science.” Being paid twenty-two shillings and sixpence a month plus free tobacco, at a time when equivalent white male workers earned twenty pounds a month, they obviously weren’t in it for the money.
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Barrett’s early departure from the Low Isles also meant that he missed Yonge’s coral physiology experiments, which were designed to investigate the feeding, digestion, excretion, and respiration of reef-growing corals, and especially their relationship with symbiotic algae (zooxanthellae). A few coral experts, including Stanley Gardiner, speculated without real proof that the tiny brown algae played an important role in coral nutrition. Others thought that the plants might boost the corals’ energy by supplying oxygen. Yonge was skeptical on both counts. He suspected that the relationship was at best commensal, with the algae the sole beneficiaries, or possibly even parasitic, at the expense of the coral hosts.
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It was obvious how algae benefited from the association. Insinuating themselves into the very cells of the coral polyps, they were thus protected from predators while still afforded access to light through the thin tissues of the coral. Like all plants, the algae needed sunlight to create energy through photosynthesis, and in the process they produced oxygen. Using their light-activated coloring matter chlorophyll, the algae built up their basic organic food of starch and sugars from a mixture of seawater elements produced by the corals. They “obtain from the excretion of the corals valuable food material,” Yonge wrote, listing these nutritional wastes as carbon dioxide, ammonia, and hydrogen. With both protection and their food and energy on tap, the little plants could hardly have found a more perfect place to live.
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It didn’t necessarily follow, though, Yonge thought, that the corals received reciprocal benefits. Such an assumption was sentimental rather than scientific, a throwback to the socialistic beliefs of pioneering biologists like Patrick Geddes and Prince Peter Kropotkin, who’d believed that cooperation and not war was nature’s way. To test this cooperative proposition with proper rigor, Yonge designed a series of elegant and trenchant experiments. He began by showing that corals were wholly carnivorous, and greedily so: they gobbled up zooplankton and shunned all vegetable enticements. And though Yonge thought these coral polyps might indeed derive some energy from oxygen, he didn’t see why they couldn’t supply this themselves by processing seawater. His experiments also showed that during daylight the algae produced far more oxygen than the corals needed: their guests’ supply was thus surplus to requirements.
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Two further experiments appeared to reveal that coral polyps did not rely on their algae tenants for survival but continued to live in the dark, apparently by eating zooplankton. When polyps were deprived of zooplankton they became markedly distressed, but well-fed corals survived whether they were in light or dark environments. Yonge did notice that after five months in the dark, corals lost all their color, but he saw no evidence that this bleaching did them any real harm, for they “were otherwise in perfect condition.” It did not occur to him that bleached corals might no longer be capable of building reefs, or that they would in fact eventually die.
Ultimately, Yonge was prepared to make two partial and tentative concessions to the idea of a cooperative symbiosis between corals and algae: “If we must have a ‘use’ for the plants, then I think that the speed with which they dispose of the waste products of the corals increases the efficiency of the latter, while they [the algae] certainly provide abundant supplies of oxygen, without which it is just possible that such immense aggregations of living matter, which constitute the coral reef … could not originate and flourish.”
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Maurice Yonge’s half-concessions to the cooperative role of zooxanthellae were later proved correct, but he failed to realize the degree to which reef-growing corals are dependent on their algae partners for the oxygen-based nutrition and energy needed to build reefs. His experiments also seemed so original and persuasive that they went largely unquestioned for the next thirty years. Still, though flawed, his findings would provide the baseline for an explosion of new work on coral symbiosis by scientists in the West Indies, the United States, and Europe during the 1960s and 1970s.
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Today we know that because of their symbiotic relationship with algae, reef-growing corals are autotrophic, meaning they are “predominantly self-sufficient in supplying nutrition from their own biological processes.” Although polyps do graze on small amounts of floating plankton, the available supply doesn’t nearly meet their needs as reef builders. Reef corals rely on the solar panels of their algae tenants to provide the prodigious energy required to produce lime-based skeletons, in the same way that we make bone. Geneticist Steve Jones points out that such algae-assisted corals are three times as efficient in the light as in the dark, and in perfect conditions can have their productivity increased a hundredfold by their tiny helpers. Thanks to the zooxanthellae waste, reef corals are able to lay down carbon at nearly twice the rate of a rain forest, “making shallow water coral reefs the most productive natural places on the planet.”
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There are many corals that are not algae-assisted, but all reef-growing corals are. They need the extra energy generated by the algae’s oxygen and sugars to grow fast enough to combat all the forces that work toward reef destruction. Maurice Yonge did not quite get this point, but his work was essential in allowing those who followed to make the discovery.
Maurice Yonge was right, though, not to idealize the relationship of polyp and plant. Their partnership is no cooperative utopia. Each partner pays a price for the contract, which seems to be built on nothing but tough Hobbesian self-interest. Though their symbiosis has survived for something like 240 million years, and has produced the Great Barrier Reef in the process, it can, and probably will, break down one day. As we’ll see in later chapters, if forced to go it alone for the sake of self-interest, corals and algae will part. Each might perhaps survive alone, but they will no longer build reefs. Steve Jones warns us: “In fact the submarine union is always on the edge, with the guest in constant danger of forced expulsion or voluntary exile, and its host of a solitary existence that may be bad for its health. The arrangement thrives when times are good, but may split up when they get nasty.”
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* * *
The Cambridge expedition’s body of scientific findings was presented in seven massive volumes between 1930 and 1968, as well as in scores of papers and books. Its global impact on coral reef science and tropical marine ecology can hardly be exaggerated. There’d been nothing like it before, and there have been few more influential expeditions since. Low Isles data is still admired and used today.
Within Australia, one emblem of the success of the partnership was the decision by the British Reef Committee to donate the Low Isles buildings to the Queensland government for a permanent marine research station. It was to be led by Frank Moorhouse and to focus on economic biology, but sadly it didn’t last long. A cyclone leveled the buildings in 1934 and this, coupled with the indifference of the Queensland government, pushed Moorhouse to resign a year later. After that the station petered out.
A more enduring by-product of the expedition was the inspiration it gave female scientists everywhere. Six of the fourteen members of the biological section were women, an astonishing statistic for its day. Sidnie Manton joined the expedition at a later date: she had received top marks in zoology at Cambridge four years earlier as a twenty-two-year-old in Girton College, but was not permitted to take the prize for being first in her class because of her gender. Already famed for her work on crustacean embryology, she threw herself into a quantitative ecological survey of Low Isles marine life, which, according to Yonge, achieved more in four months than the rest of the party over the full year. Manton later became one of the first women fellows of the Royal Society. For her part, Sheina Marshall ended her stellar career as deputy director of the University of London’s famous marine research station at Millport, Scotland.
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News of their colleagues’ presence on the island acted as a magnet for Australian women scientists. Dr. Gwynneth Buchanan, a lecturer in the University of Melbourne’s zoology department, joined them for a short visit, and a botanist, Mary P. Glynne, made a brief survey of the Low Isles in April 1929. Perhaps the most illustrious visitor was Freda Bage, biologist and head of the Women’s College at the University of Queensland. When the Great Barrier Reef Committee learned of the forthcoming contingent of women from Cambridge, they quickly moved to appoint Freda Bage as their first female member. She hosted all the expedition’s women scientists in Brisbane, organized talks to graduates, and energetically publicized their work.
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The expedition’s contribution to the economic biology of the Reef proved less impressive. Moorhouse’s work on the life histories of trochus and goldlip oysters was genuinely original, but Yonge’s own “Economic Report” was lame by comparison. Although the latter was quoted approvingly in local Australian newspapers, Yonge’s findings had been cobbled together during a short trip to the Torres Strait on his way back to Britain. Most of his recommendations were either contradictory or perfunctory. Despite noting a serious depletion of green turtle stocks, he concluded that this species, along with dugong, bêche-de-mer, and hawksbill turtle, could be more efficiently exploited through improved scientific methods. At the same time he urged the Queensland government to impose tougher restrictions on hunting dugong, and to develop a plan for the biological study of all potentially commercial species, including sardines, which were abundant in the waters of Murray Island.
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Maurice Yonge’s most important contribution to the Reef’s future economy was partly unintentional. His popular memoir,
A Year on the Great Barrier Reef
(1930), projected a time “not far distant when … the sand cays of the Capricorns will each possess its hotel and guest house.” The modest Maurice never guessed he would be an instrument of his own prophecy, and that the Cambridge expedition and his book would ignite new fascinations with the Reef, among tourists as well as scientists, on both sides of the world. No scientist had written about the Reef with such a combination of passion and precision since the neglected geologist Joseph Beete Jukes, nearly a century earlier.
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Yonge recalled that one of his most enduring memories was the sight and sound of Pacific breakers smashing onto the limestone ramparts of the outer Barrier Reef.
Towering far above, 15 or 10 feet high, they came curling over and hung poised for a moment of time, grey and green and lowering under a dull, storm-racked sky, to fall with the noise of thunder and in a cascade of foam that came rushing up, a swirling flood to the summit of the reef. One was in the presence of forces far beyond the control, almost beyond the conception of man … The reef platform, now awash, was the only “land” to break the surface of the sea, and that land … with infinite labour built up by the lowliest animals and plants, adding grain by grain—nay, atom by atom—to their skeletons of lime, uniting, spreading, consolidating, resisting the fury of the sea and attacks of enemies, never resting, nor yielding, but converting the very substance of the sea itself into a submarine mountain chain of limestone, against which even the tempest-driven Pacific is utterly unavailing.
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One of Yonge’s admiring Australian readers was a schoolteacher named Edwin Montague Embury, from the northern New South Wales country town of Manilla. The son of a wool scourer, “Mont” had grown up an ardent nature lover, before enlisting with the Australian Imperial Force in 1914. He returned to work in a bush school after the war, and there he “taught himself the essential elements of Reef and Coral structure and the creatures which inhabit this unique environment.” His accurate and delightful little school primer, drawing on the writings of Banfield, Saville-Kent, and Yonge, was one result.
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