by Bill Bryson
“You’re kidding,” I said. There wasn’t a moment when there weren’t two cars passing beneath it, all filled with, in the most literal sense, happy campers.
“Oh, it’s not likely,” he added. “I’m just saying it could. Equally, it could stay like that for decades. There’s just no telling. People have to accept that there is risk in coming here. That’s all there is to it.”
As we walked back to his vehicle to head back to Mammoth Hot Springs, Doss added: “But the thing is, most of the time bad things don’t happen. Rocks don’t fall. Earthquakes don’t occur. New vents don’t suddenly open up. For all the instability, it’s mostly remarkably and amazingly tranquil.”
“Like the Earth itself,” I remarked.
“Precisely,” he agreed.
The risks at Yellowstone apply to park employees as much as to visitors. Doss had got a horrific sense of that in his first week on the job five years earlier. Late one night, three young summer employees were engaging in an illicit activity known as “hot-potting”—swimming or basking in warm pools. Though the park, for obvious reasons, doesn’t publicize it, not all the pools at Yellowstone are dangerously hot. Some are extremely agreeable to lie in, and it was the habit of some of the summer employees to have a dip late at night, even though it was against the rules to do so. Foolishly, the threesome had failed to take a torch, which was extremely dangerous because much of the soil around the warm pools is crusty and thin and one can easily fall through into a scalding vent below. In any case, as they made their way back to their dorm, they came across a stream that they had had to leap over earlier. They backed up a few paces, linked arms and, on the count of three, took a running jump. In fact, it wasn’t the stream at all. It was a boiling pool. In the dark they had lost their bearings. None of the three survived.
I thought about this the next morning as I made a brief call, on my way out of the park, at a place called Emerald Pool, in the Upper Geyser Basin. Doss hadn’t had time to take me there the day before, but I thought I ought at least to have a look at it, for Emerald Pool is a historic site.
In 1965, a husband and wife team of biologists named Thomas and Louise Brock, while on a summer study trip, had done a crazy thing. They had scooped up some of the yellowy-brown scum that rimmed the pool and examined it for life. To their, and eventually the wider world’s, deep surprise, it was full of living microbes. They had found the world’s first extremophiles—organisms that could live in water that had previously been assumed to be much too hot or acid or choked with sulphur to bear life. Emerald Pool, remarkably, was all these things, yet at least two types of living thing, Sulpholobus acidocaldarius and Thermophilus aquaticus, as they became known, found it congenial. It had always been supposed that nothing could survive above temperatures of 50 degrees Celsius, but here were organisms basking in rank, acidic waters nearly twice that hot.
For almost twenty years, one of the Brocks’ two new bacteria, Thermophilus aquaticus, remained a laboratory curiosity—until a scientist in California named Kary B. Mullis realized that heat-resistant enzymes within it could be used to create a bit of chemical wizardry known as a polymerase chain reaction, which allows scientists to generate lots of DNA from very small amounts—as little as a single molecule in ideal conditions. It’s a kind of genetic photocopying, and it became the basis for all subsequent genetic science, from academic studies to police forensic work. It won Mullis the Nobel Prize in chemistry in 1993.
Many of Yellowstone’s mineral pools—this is Grand Prismatic Spring—are boiling hot, so it came as a great surprise when biologists Thomas and Louise Brock found microbes thriving in water heated to nearly 100°C. Such organisms, called extremophiles, give interesting hints as to how life on Earth may have arisen. (credit 15.9)
Meanwhile, scientists were finding even hardier microbes, now known as hyperthermophiles, which demand temperatures of 80 degrees Celsius or more. The warmest organism found so far, according to Frances Ashcroft in Life at the Extremes, is Pyrolobus fumarii, which dwells in the walls of ocean vents where the temperature can reach 113 degrees Celsius. The upper limit for life is thought to be about 120 degrees Celsius, though no one actually knows. At all events, the Brocks’ findings completely changed our perception of the living world. As NASA scientist Jay Bergstralh has put it: “Wherever we go on Earth—even into what’s seemed like the most hostile possible environments for life—as long as there is liquid water and some source of chemical energy we find life.”
Life, it turns out, is infinitely more clever and adaptable than anyone had ever supposed. This is a very good thing for, as we are about to see, we live in a world that doesn’t altogether seem to want us here.
A single strip of deoxyribonucleic acid—better known as DNA. DNA stores the code that is the genetic information essential to the creation of every living organism. (credit p5.1)
LONELY PLANET
It isn’t easy being an organism. In the whole universe, as far as we yet know, there is only one place, an inconspicuous outpost of the Milky Way called the Earth, that will sustain you, and even it can be pretty grudging.
From the bottom of the deepest ocean trench to the top of the highest mountain, the zone that covers nearly the whole of known life is only around 20 kilometres thick—not much when set against the roominess of the cosmos at large.
For humans it is even worse because we happen to belong to the portion of living things that took the rash but venturesome decision 400 million years ago to crawl out of the seas and become land-based and oxygen-breathing. In consequence, no less than 99.5 per cent of the world’s habitable space by volume, according to one estimate, is fundamentally—in practical terms completely—off limits to us.
It isn’t simply that we can’t breathe in water, but that we couldn’t bear the pressures. Because water is about 1,300 times heavier than air, pressures rise swiftly as you descend—by the equivalent of one atmosphere for every 10 metres of depth. On land, if you rose to the top of a 150-metre eminence—Cologne Cathedral or the Washington Monument, say—the change in pressure would be so slight as to be indiscernible. At the same depth under water, however, your veins would collapse and your lungs would compress to the approximate dimensions of a Coke can. Amazingly, people do voluntarily dive to such depths, without breathing apparatus, for the fun of it, in a sport known as free diving. Apparently, the experience of having your internal organs rudely deformed is thought exhilarating (though not, presumably, as exhilarating as having them return to their former dimensions upon resurfacing). To reach such depths, however, divers must be dragged down, and quite briskly, by weights. Without assistance, the deepest anyone has gone and lived to talk about it afterwards is 72 metres—a feat performed by an Italian named Umberto Pelizzari, who in 1992 dived to that depth, lingered for a nanosecond and then shot back to the surface. In terrestrial terms, 72 metres is a good bit shorter than a football pitch. So even in our most exuberant stunts we can hardly claim to be masters of the abyss.
Other organisms do, of course, manage to deal with the pressures at depth, though quite how some of them do so is a mystery. The deepest point in the ocean is the Mariana Trench in the Pacific. There, some 11.3 kilometres down, the pressures rise to over 16,000 pounds per square inch. We have managed just once, briefly, to send humans to that depth in a sturdy diving vessel, yet it is home to colonies of amphipods, a type of crustacean similar to shrimp but transparent, which survive without any protection at all. Most oceans are of course much shallower, but even at the average ocean depth of 4 kilometres the pressure is equivalent to being squashed beneath a stack of fourteen loaded cement trucks.
Nearly everyone, including the authors of some popular books on oceanography, assumes that the human body would crumple under the immense pressures of the deep ocean. In fact, this appears not to be the case. Because we are made largely of water ourselves, and water is “virtually incompressible,” in the words of Frances Ashcroft of Oxford University “the body remains at the same p
ressure as the surrounding water, and is not crushed at depth.” It is the gases inside your body, particularly in the lungs, that cause the trouble. These do compress, though at what point the compression becomes fatal is not known. Until quite recently it was thought that anyone diving to 100 metres or so would die painfully as his or her lungs imploded or chest wall collapsed, but the free divers have repeatedly proved otherwise. It appears, according to Ashcroft, that “humans may be more like whales and dolphins than had been expected.”
Umberto Pelizzari, the world’s most successful free diver, surfaces after plunging (with the assistance of weights) to a depth of 131 metres without breathing apparatus in 2001. Until recently it was thought no human could survive at such depths. (credit 16.1)
Plenty else can go wrong, however. In the days of diving suits—the sort that were connected to the surface by long hoses—divers sometimes experienced a dreaded phenomenon known as “the squeeze.” This occurred when the surface pumps failed, leading to a catastrophic loss of pressure in the suit. The air would leave the suit with such violence that the hapless diver would be, all too literally, sucked up into the helmet and hosepipe. When hauled to the surface, “all that is left in the suit are his bones and some rags of flesh,” the biologist J. B. S. Haldane wrote in 1947, adding for the benefit of doubters, “This has happened.”
(Incidentally, the original diving helmet, designed in 1823 by an Englishman named Charles Deane, was intended not for diving but for fire fighting. It was called a “smoke helmet,” but, being made of metal, it was hot and cumbersome; as Deane soon discovered, fire-fighters had no particular eagerness to enter burning structures in any form of attire, but most especially not in something that heated up like a kettle and made them clumsy into the bargain. In an attempt to save his investment, Deane tried it under water and found it was ideal for salvage work.)
Typical nineteenth-century diving machines. Such equipment allowed divers for the first time to spend prolonged periods under water, but difficulties in controlling air pressure meant constant risk to their lives. (credit 16.2)
The real terror of the deep, however, is the bends—not so much because they are unpleasant, though of course they are, as because they are so much more likely. The air we breathe is 80 per cent nitrogen. Put the human body under pressure, and that nitrogen is transformed into tiny bubbles that migrate into the blood and tissues. If the pressure is changed too rapidly—as with a too-quick ascent by a diver—the bubbles trapped within the body will begin to fizz in exactly the manner of a freshly opened bottle of champagne, clogging tiny blood vessels, depriving cells of oxygen and causing pain so excruciating that sufferers are prone to bend double in agony—hence “the bends.”
The bends have been an occupational hazard for sponge and pearl divers since time immemorial, but didn’t attract much attention in the Western world until the nineteenth century, and then it was among people who didn’t get wet at all (or at least, not very wet and not generally much above the ankles). They were caisson workers. Caissons were enclosed dry chambers built on river beds to facilitate the construction of bridge piers. They were filled with compressed air, and often when the workers emerged after an extended period of working under this artificial pressure they experienced mild symptoms like tingling or itchy skin. But an unpredictable few felt more insistent pain in the joints and occasionally collapsed in agony, sometimes never to get up again.
Cutaway drawing of an early twentieth-century steel caisson, an enclosed chamber that allowed men to work beneath water. An occupational hazard for such workers was the excruciating condition known as “the bends.” (credit 16.3)
It was all most puzzling. Sometimes the workers would go to bed feeling fine, but wake up paralysed. Sometimes they wouldn’t wake up at all. Ashcroft relates a story concerning the directors of a new tunnel under the Thames who held a celebratory banquet as the tunnel neared completion. To their consternation their champagne failed to fizz when uncorked in the compressed air of the tunnel. However, when at length they emerged into the fresh air of a London evening, the bubbles sprang instantly to fizziness, memorably enlivening the digestive process.
Apart from avoiding high-pressure environments altogether, only two strategies are reliably successful against the bends. The first is to suffer only a very short exposure to the changes in pressure. That is why the free divers I mentioned earlier can descend to depths of 150 metres without ill effect. They don’t stay down long enough for the nitrogen in their system to dissolve into their tissues. The other solution is to ascend by careful stages. This allows the little bubbles of nitrogen to dissipate harmlessly.
A great deal of what we know about surviving at extremes is owed to the extraordinary father and son team of John Scott and J. B. S. Haldane. Even by the demanding standards of British intellectuals, the Haldanes were outstandingly eccentric. The senior Haldane was born in 1860 to an aristocratic Scottish family (his brother was Viscount Haldane), but spent most of his career in comparative modesty as a professor of physiology at Oxford. He was famously absent-minded. Once, after his wife had sent him upstairs to change for a dinner party, he failed to return and was discovered asleep in bed in his pyjamas. When roused, Haldane explained that he had found himself disrobing and assumed it was bedtime. His idea of a holiday was to travel to Cornwall to study hookworm in miners. Aldous Huxley, the novelist grandson of T. H. Huxley, who lived with the Haldanes for a time, parodied him, a touch mercilessly, as the scientist Edward Tantamount in the novel Point Counter Point.
Haldane’s gift to diving was to work out the rest intervals necessary to manage an ascent from the depths without getting the bends, but his interests ranged across the whole of physiology, from studying altitude sickness in climbers to the problems of heatstroke in desert regions. He had a particular interest in the effects of toxic gases on the human body. To understand more exactly how carbon monoxide leaks killed miners, he methodically poisoned himself, carefully taking and measuring his own blood samples the while. He quit only when he was on the verge of losing all muscle control and his blood saturation level had reached 56 per cent—a level, as Trevor Norton notes in his entertaining history of diving, Stars Beneath the Sea, only fractionally removed from nearly certain lethality.
Haldane’s son Jack, known to posterity as J.B.S., was a remarkable prodigy who took an interest in his father’s work almost from infancy. At the age of three he was overheard demanding peevishly of his father, “But is it oxyhaemoglobin or carboxyhaemoglobin?” Throughout his youth, the young Haldane helped his father with experiments. By the time he was a teenager, the two often tested gases and gas masks together, taking it in turns to see how long it took them to pass out.
Though J. B. S. Haldane never took a degree in science (he studied classics at Oxford), he became a brilliant scientist in his own right, mostly working for the government at Cambridge. The biologist Peter Medawar, who spent his life around mental Olympians, called him “the cleverest man I ever knew.” Huxley parodied the younger Haldane too, in his novel Antic Hay, but also used his ideas on genetic manipulation of humans as the basis for the plot of Brave New World. Among many other achievements, Haldane played a central role in marrying Darwinian principles of evolution to the genetic work of Gregor Mendel to produce what is known to geneticists as the Modern Synthesis.
Perhaps uniquely among human beings, the younger Haldane found the First World War “a very enjoyable experience” and freely admitted that he “enjoyed the opportunity of killing people.” He was himself wounded twice. After the war he became a successful popularizer of science and wrote twenty-three books (as well as over four hundred scientific papers). His books are still thoroughly readable and instructive, though not always easy to find. He also became an enthusiastic Marxist. It has been suggested, not altogether cynically, that this was out of a purely contrarian instinct and that if he had been born in the Soviet Union he would have been a passionate monarchist. At all events, most of his articles first app
eared in the Communist Daily Worker.
Whereas his father’s principal interests concerned miners and poisoning, the younger Haldane became obsessed with saving submariners and divers from the unpleasant consequences of their work. With Admiralty funding, he acquired a decompression chamber that he called the “pressure pot.” This was a metal cylinder into which three people at a time could be sealed and subjected to tests of various types, all painful and nearly all dangerous. Volunteers might be required to sit in ice water while breathing “aberrant atmosphere,” or subjected to rapid changes of pressurization. In one experiment, Haldane himself simulated a dangerously hasty ascent to see what would happen. What happened was that the dental fillings in his teeth exploded. “Almost every experiment,” Norton writes, “ended with someone having a seizure, bleeding or vomiting.” The chamber was virtually soundproof, so the only way for occupants to signal unhappiness or distress was to tap insistently on the chamber wall or to hold up notes to a small window.
On another occasion, while poisoning himself with elevated levels of oxygen, Haldane had a fit so severe that he crushed several vertebrae. Collapsed lungs were a routine hazard. Perforated eardrums were quite common, too; but, as Haldane reassuringly noted in one of his essays, “the drum generally heals up; and if a hole remains in it, although one is somewhat deaf, one can blow tobacco smoke out of the ear in question, which is a social accomplishment.”
What was extraordinary about this was not that Haldane was willing to subject himself to such risk and discomfort in the pursuit of science, but that he had no trouble talking colleagues and loved ones into climbing into the chamber, too. Sent on a simulated descent, his wife once had a fit that lasted thirteen minutes. When at last she stopped bouncing across the floor, she was helped to her feet and sent home to cook dinner. Haldane happily employed whoever happened to be around, including on one memorable occasion a former Prime Minister of Spain, Juan Negrín. Dr. Negrín complained afterwards of minor tingling and “a curious velvety sensation on the lips” but otherwise seems to have escaped unharmed. He may have considered himself very lucky. A similar experiment with oxygen deprivation left Haldane without feeling in his buttocks and lower spine for six years.
