The World Without Us - Alan Weisman (2007)

Part IV

Chapter 19. The Sea Cradle


HE SHARKS HAVE never seen humans before. And few humans present have ever seen so many sharks.

Except for moonlight, the sharks have also never seen the equatorial night be anything other than dark and deep. Nor have the eel fish, which resemble 5-foot silver ribbons with fins and needle snouts as they skitter up to the research vessel White Holly’s steel hull, entranced by shafts of color drilled into the night sea by spotlights from the captain’s deck. Too late, they notice that the waters here are boiling with dozens of white-tipped, black-tipped, and gray reef sharks racing in delirious circles that scream hunger.

A quick squall comes and goes, blowing a curtain of warm rain across the lagoon where the ship is anchored and drenching the remains of a deckside chicken dinner eaten over a plastic tarp stretched across the dive master’s table. Still, the scientists linger at the White Holly’s railing, fascinated by thousands of pounds of sharks—sharks proving that they rule the food pyramid here by snatching eel fish in mid-flight as they leap between swells. Twice a day for the past four days, these people have swum among such sleek predators, counting them and everything else alive in the water, from swirling rainbows of reef fish to iridescent coral forests; from giant clams lined with velvety, multihued algae down to microbes and viruses.

This is Kingman Reef, one of the hardest places to reach on Earth. To the naked eye, it barely exists: a change from cobalt blue to aquamarine is the main clue that a nine-mile-long coral boomerang lies submerged 15 meters below the surface of the Pacific, 1,000 miles southwest of Oahu. At low tide two islets rise barely a meter above the water, mere slivers consisting of giant clamshell rubble heaped by storms against the reef. During World War II, the U.S. Army designated Kingman a way-station anchorage between Hawaii and Samoa, but never used it.

Gray reef shark. Carcharhinus amblyrhynchos. Kingman Reef.


Two dozen scientists aboard the White Holly and their sponsor, Scripps Institution of Oceanography, have come to this water-world-without-people to glimpse what a coral reef looked like before human beings appeared on Earth. Without such a baseline, there can be little agreement on what constitutes a healthy reef, let alone on how to help nurse these aquatic equivalents of rain forest diversity back to whatever that might be. Although months of sifting data lie ahead, already these researchers have found evidence that contradicts convention, and seems counterintuitive even to themselves. But there it is, thrashing just off starboard.

Between these sharks and an omnipresent species of 25-pound red snappers equipped with noticeable fangs—one of which sampled a photographer’s ear—it appears that big carnivores account for more total biomass than anything else here. If so, that would mean that at Kingman Reef, the conventional notion of a food pyramid is standing on its pointy head.

Two-spot red snapper. Lutjanus bohar, Palmyra Atoll.


As ecologist Paul Colinvaux described in a seminal 1978 book, Why Big Fierce Animals Are Rare, most animals feed on creatures smaller and many times more numerous than themselves. Because roughly only 10 percent of the energy they consume converts to body mass, millions of little insects must feast on 10 times their total weight in tiny mites. The bugs themselves are gobbled by a correspondingly smaller number of small birds, which in turn are hunted by far fewer foxes, wildcats, and large raptors.

Even more than by head counts, Colinvaux wrote, the food pyramid’s shape is defined by mass: “All the insects in a woodlot weigh many times as much as all the birds; and all the songbirds, squirrels, and mice combined weigh vastly more than all the foxes, hawks, and owls combined.”

None of the scientists on this August, 2005 expedition, who hail from America, Europe, Asia, Africa, and Australia, would dispute those conclusions—on land. Yet the sea may be special. Or perhaps it’s terra firma that is the exception. In a world with or without people, two-thirds of its surface is that mutable one on which the White Holly lightly bobs to pulsations that rock the planet. From the vantage of Kingman Reef, there are no easy contours to define our spaces, because the Pacific has no boundaries. It stretches until it blends into the Indian and the Antarctic, and squeezes through the Bering Strait into the Arctic, all of which in turn mix into the Atlantic. At one time, the Earth’s great sea was the origin of everything that breathes and reproduces. As it goes, so goes everything’s future.


Jeremy Jackson has to duck to take shade under an awning on the White Holly’s upper deck, where the stern of this former naval cargo hauler has been converted to an invertebrate laboratory. Jackson, a Scripps marine paleoecologist with limbs and ponytail so long he suggests a king crab that short-circuited evolution, springing straight from the sea into human form, had the original idea for this mission. Jackson has spent much of his career in the Caribbean, watching the pressures of fishing and planetary warming flatten the Gruyère-cheese architecture of living coral reefs to bleached marine slag. As corals die and collapse, they and the myriad life-forms that call their crevices home, and everything that eats them, get displaced by something slick and unpleasant. Jackson leans over trays of algae that seaweed expert Jennifer Smith collected in previous stops on the way to Kingman.

“That’s what we get on the slippery slope to slime,” he tells her again. “Plus jellyfish and bacteria—the marine equivalent of rats and roaches.”

Four years earlier, Jeremy Jackson had been invited to Palmyra Atoll, the northernmost of the Line Islands: a tiny Pacific archipelago divided by the equator and split between two nations, Kiribati and the United States. Palmyra had recently been purchased by The Nature Conservancy for coral reef research. During World War II, the U.S. Navy built an air station on Palmyra, opened channels into one lagoon, and dumped enough munitions and 55-gallon diesel drums in another that it was later dubbed Black Lagoon for its resident pool of dioxins. Except for a small U.S. Fish and Wildlife maintenance staff, Palmyra is uninhabited, its abandoned naval buildings half-dissolved into the surf. One semi-submerged boat hull is now a planter box stuffed with coconut palms. Coconut, introduced here, has all but vanquished native pisonia forests, and rats have replaced land crabs as the top predator.

Jackson’s impression radically changed, however, when he jumped into the water. “I could barely see 10 percent of the bottom,” he told his Scripps colleague Enric Sala when he returned. “My view was blocked by sharks and big fish. You have to go there.”

Sala, a young conservation marine biologist from Barcelona, had never known big sea species in his native Mediterranean. In a strictly policed reserve off Cuba, he had seen a remnant population of 300-pound groupers. Jeremy Jackson had traced Spanish maritime records back to Columbus to verify that 800-pound versions of these monsters once spawned in huge numbers around Caribbean reefs, in the company of 1,000-pound sea turtles. On Columbus’s second voyage to the New World, the seas off the Greater Antilles were so thick with green turtles that his galleons practically ran aground on them.

Jackson and Sala coauthored papers describing how our era’s perspective had deluded us into thinking that a coral reef populated by colorful but puny, aquarium-sized fish was pristine. Only two centuries earlier, it was a world where ships collided with whole schools of whales, and where sharks were so big and abundant they swam up rivers to prey on cattle. The northern Line Islands, they decided, presented an opportunity to follow a gradient of decreasing human population and, they suspected, increasing animal size. At the end closest to the equator was Kiritimati, also known as Christmas Island, the world’s largest coral atoll, with 10,000 people on just over 200 square miles. Next came Tabuaeran (Fanning) and a 3-square-mile speck called Teraina (Washington), with 1,900 and 900 people, respectively. Then Palmyra, with 10 staff researchers—and 30 miles farther, a sunken island where only the fringe reef that once encircled it remained: Kingman.

Other than copra—dried coconut—and a few pigs for local consumption, there is no agriculture on Kiritimati-Christmas Island. Still, in the first days of the 2005 expedition that Sala eventually organized, researchers aboard the White Holly were startled by the gush of nutrients from the island’s four villages, and by the slime they found coating the reefs where grazers like parrotfish had been heavily fished. At Tabuaeran, rotting iron from a sunken freighter was feeding even more algae. Tiny Teraina, far overpopulated for its size, had no sharks or snappers at all. Humans there used rifles to fish the surf for sea turtles, yellowfin tuna, red-footed boobies, and melonhead whales. The reef bore a four-inch-thick mat of green seaweed.

Submerged Kingman Reef, northernmost of all, had once been the size of Hawaii’s Big Island, with a volcano to match. Its caldera now lies below its lagoon, leaving only its coral ring barely visible. Because corals live in symbiosis with friendly, one-celled algae that require sunlight, as Kingman’s cone keeps sinking, the reef will go, too—already its west side has drowned, leaving the boomerang shape that allowed the White Holly to enter and anchor in the lagoon.

“So ironic,” marveled Jackson, after 70 sharks greeted the team’s first dive, “that the oldest island, sinking beneath the waves like a 93-year-old man with three months before he dies, is the healthiest against the ravages of man.”

Armed with measuring tape, waterproof clipboards, and three-foot PVC lances to discourage toothy natives, the teams of wet-suited scientists counted corals, fish, and invertebrates all around Kingman’s broken ring, sampling up to four meters on either side of multiple 25-meter transect lines they lay beneath the transparent Pacific. To examine the microbial base of the entire reef community, they suctioned coral mucus, plucked seaweed, and filled hundreds of liter flasks with water samples.

Besides the mostly curious sharks, unfriendly snappers, furtive moray eels, and intermittent schools of five-foot barracuda, the researchers also swam through swirling shoals of fusiliers, lurking peacock groupers, hawkfish, damselfish, parrotfish, surgeonfish, befuddling variations on the yellow-blue theme of angelfish, and striped, crosshatched, and herringbone permutations of black-yellow-silver butterfly fish. The huge diversity and myriad niches of a coral reef enable each species, so close in body shape and plan, to find different ways to make a living. Some feed only on one coral, some only on another; some switch between coral and invertebrates; some have long bills to poke into interstitial spaces that conceal tiny mollusks. Some prowl the reef by daylight while others sleep, with the whole assemblage changing places at night.

“It’s kind of like hot-bunking in submarines,” explains Alan Friedlander of Hawaii’s Oceanic Institute, one of the expedition’s fish experts. “Guys take four-to-six-hour shifts, switching bunks. The bunk never stays cold for very long.”

Vibrant as it is, Kingman Reef is still the aquatic equivalent of an oasis in mid-desert, thousands of miles from any significant landmass for trading and replenishing seed. The 300–400 fish species here are fewer than half of what’s on display in the great Pacific coral reef diversity triangle of Indonesia, New Guinea, and the Solomon Islands. Yet the pressure of aquarium-trade capture and overfishing by dynamite and cyanide have stressed those places nearly to breaking, and left them bereft of large predators.

“There’s no place left in the ocean like the Serengeti that puts it all together,” observes Jeremy Jackson.

Yet Kingman Reef, like the Bialowieza Puszcza, is a time machine, an intact fragment of what used to surround every green dot in this big blue ocean. Here, the coral team finds a half-dozen unknown species. The invertebrate crew brings back strange mollusks. The microbe team discovers hundreds of new bacteria and viruses, largely because no one has ever before tried to chart the microscopic universe of a coral reef.

In a sweltering cargo hold below decks, microbiologist Forest Rohwer has mini-cloned the lab he runs at San Diego State. Using an oxygen probe just one micron across that’s hooked to a microsensor and a laptop, his team has demonstrated exactly how algae that they collected earlier at Palmyra are supplanting living corals. In small glass cubes they built and filled with seawater, they placed bits of coral and seaweed algae separated by a glass membrane so fine that not even viruses can pass through it. Sugars produced by the algae can, however, because they dissolve. When bacteria living on coral feed on this rich extra nutrient, they consume all the available oxygen, and the coral dies.

To verify this finding, the microbiology team dosed some cubes with ampicillin to kill the hyperventilating bacteria, and those corals remained healthy. “In every case,” says Rohwer, climbing out of the hold into the considerably cooler afternoon, “stuff dissolving out of the algae kills the coral.”

So where is all the weedy algae coming from? “Normally,” he explains, lifting his nearly waist-length black hair to catch a breeze on the back of his neck, “coral and algae are in happy equilibrium, with fish grazing on the algae and cropping it. But if water quality around a reef goes down, or if you remove grazing fish from the system, algae get the upper hand.”

In a healthy ocean such as at Kingman Reef, there are a million bacteria per milliliter, doing the world’s work by controlling the movements of nutrients and carbon through the planet’s digestive system. Around the populated Line Islands, however, some samples show 15 times as much bacteria. Taking up oxygen, they choke coral, gaining ground for yet more algae to feed yet more microbial bacteria. It’s the slimy cycle that Jeremy Jackson fears, and Forest Rohwer agrees that it could well happen.

“Microbes don’t really much care whether we—or anything else—are here or not. We’re just a semi-interesting niche for them. In fact, there’s been just a very brief period of time when there were anything butmicrobes on the planet. For billions of years, that’s all there was. And when the sun starts to expand, we’ll go, and it’ll only be microbes, for millions or billions of years more.”

They will remain, he says, until the sun dries up the last water on Earth, because microbes need it to thrive and reproduce. “Although they can be stored by freeze-drying, and do just fine. Everything we shoot into space has microbes on it, despite people’s efforts to not let that happen. Once it’s out there, there’s no reason why some of this stuff couldn’t make it billions of years.”

The one thing microbes could never have done was take over the land the way more complex cell structures finally did, building plants and trees that invited more complex life-forms to dwell in them. The only structures microbes create are mats of slime, a regression toward the first life-forms on Earth. To these scientists’ palpable relief, here at Kingman that hasn’t happened yet. Pods of bottlenose dolphins accompany the dive boats to and from the White Holly, leaping to snag plentiful flying fish. Each underwater transect reveals more richness, ranging from gobies, a fish less than a’ centimeter long, to manta rays the size of Piper Cubs, and hundreds of sharks, snappers, and big jacks.

The reefs themselves, blessedly clean, are lush with table corals, plate corals, lobe corals, brain corals, and flower corals. At times, the walls of coral nearly disappear behind colored clouds of smaller grazing fish. The paradox that this expedition has confirmed is that their sheer abundance is caused by the hordes of hungry predators that devour them. Under such predation pressure, small herbivores reproduce even faster.

“It’s like when you mow your lawn,” explains Alan Friedlander. “The more you crop it, the more quickly grass grows. If you let it go awhile, the growth rate levels off.”

No chance of that happening with all of Kingman’s resident sharks. Parrotfish, whose beak-like incisors evolved to gnaw the most tenacious coral-choking algae, even change sex to maintain their sizzling reproduction rates. The healthy reef keeps its system in balance by providing nooks and crevices in which small fish hide long enough to breed before becoming shark food. As a result of the constant conversion of plant and algae nutrients into short-lived little fish, the long-lived apex predators end up accumulating most of the biomass.

The expedition data would later show that fully 85 percent of the live weight at Kingman Reef was accounted for by sharks, snappers, and other carnivorous company. How many PCBs may have migrated up the food chain and now saturate their tissues is fodder for a future study.

Two days before the expedition’s scientists depart Kingman, they steer their dive boats to the twin crescent islets heaped atop the northern arm of the boomerang-shaped reef. In the shallows, they find a heartening sight: a spectacular community of spiny black, red, and green sea urchins, robust grazers of algae. A 1998 El Nino temperature fluctuation, ratcheted even higher by global warming, knocked out 90 percent of the sea urchins in the Caribbean. Unusually warm water shocked coral polyps into spitting out friendly algal photosynthesizers that live in tight symbiosis with them, trading just the right balance of sugars for ammonia fertilizer the corals excrete back, and also providing their color. Within a month, more than half the Caribbean reefs had turned to bleached coral skeletons, now coated with slime.

Like corals worldwide, the ones at the Kingman islets’ edges also show bleaching scars, but fierce grazing has kept invasive algae at bay, allowing encrusting pink corallines to slowly cement the wounded reef back together. Wading gingerly around all the sea urchin spikes, the researchers climb ashore. Within a few yards, they’re on the windward side of the clamshell rubble, where they get a shock.

From one end to the other, each isle is carpeted with crushed plastic bottles, parts of polystyrene floats, nylon shipping ties, Bic lighters, flip-flops in various states of ultraviolet disintegration, plastic bottle caps of assorted sizes, squeeze-tubes of Japanese hand lotion, and a galaxy of multicolored plastic fragments shattered beyond identity.

The only organic detritus is the skeleton of a red-footed booby, chunks of an old wooden outrigger, and six coconuts. The following day, the scientists return after their final dive and fill dozens of garbage bags. They are under no illusions that they have returned Kingman Reef to the pristine state it was in before humans ever found it. Asian currents will bring more plastic; rising temperatures will bleach more corals—possibly all of them, unless coral and its photosynthetic resident algal partner can evolve new symbiotic agreements quickly.

Even the sharks, they now realize, are evidence of human intervention. Only one that they’ve seen in Kingman all week was a behemoth longer than six feet; the rest are apparently adolescents. Within the past two decades, shark finners must have been here. In Hong Kong, shark fin soup commands up to $100 per bowl. After slicing off their pectoral and dorsal fins, finners throw mutilated sharks, still alive, back into the sea. Rudderless, they sink to the bottom and suffocate. Despite campaigns to ban the delicacy, in less remote waters an estimated 100 million sharks die this way every year. The presence of so many vigorous young ones, at least, gives hope that enough sharks here escaped the blade to revive the population. PCBs or not, they look to be prospering.

“In a year,” observes Enric Sala, watching their spotlit frenzy that night from the rail of the White Holly, “humans take 100 million sharks, while sharks attack maybe 15 people. This is not a fair fight.”

Enric Sala stands on the shore of Palmyra Atoll, waiting for a turbo-prop Gulfstream to land on the airstrip built here the last time the world was officially at war, to take his expedition team back to Honolulu—a threehour flight. From there, they’ll disperse across the globe with their data. When they meet again, it will be electronically, and then in peer-reviewed papers they will coauthor.

Palmyra’s soft green lagoon is pure and lucid, its tropical splendor patiently erasing crumbled concrete slabs where thousands of sooty terns now roost. The tallest structure here, a former radar antenna, has rusted in half; within a few more years, it will disappear completely among the coconut palms and almond trees. If all human activity suddenly collapsed along with it, Sala believes that quicker than we’d expect, the reefs of the northern Line Islands could be as complex as they were in the last few thousand years before they were found by men bearing nets and fishhooks. (And rats: probably the onboard, self-reproducing food supply for Polynesian mariners who dared cross this endless ocean with only canoes and courage.)

“Even with global warming, I think reefs would recover within two centuries. It would be patchy. In some places, lots of large predators. Others would be coated with algae. But in time, sea urchins would return. And the fish. And then the corals.”

His thick dark eyebrows arch beyond the horizon to picture it. “In 500 years, if a human came back, he’d be completely terrified to jump in the ocean, because there would be so many mouths waiting for him.”

Jeremy Jackson, in his sixties, was the elder ecological statesman on this expedition. Most here, like Enric Sala, are in their thirties, and some are younger graduate students. They are of a generation of biologists and zoologists who increasingly append the word conservation to their titles. Inevitably, their research involves fellow creatures touched, or simply mauled, by the current worldwide peak predator, their own species. Fifty more years of the same, they know, and coral reefs will look very different. Scientists and realisrs all, yet their glimpse at how inhabitants of Kingman Reef thrive in the natural balance to which they evolved has only hardened their resolve to restore equilibrium—with humans still around to marvel.

A coconut crab, the world’s largest land invertebrate, waddles by. Flashes of pure white amid the almond leaves overhead are the new plumage of fairy tern chicks. Removing his sunglasses, Sala shakes his head.

“I’m so amazed,” he says, “by the ability of life to hang on to anything. Given the opportunity, it goes everywhere. A species as creative and arguably intelligent as our own should somehow find a way to achieve a balance. We have a lot to learn, obviously. But I haven’t given up on us.”

At his feet, thousands of tiny, trembling shells are being resuscitated by hermit crabs. “Even if we don’t: if the planet can recover from the Permian, it can recover from the human.”

With or without human survivors, the planet’s latest extinction will come to an end. Sobering as the current cascading loss of species is, this is not another Permian, or even a rogue asteroid. There is still the sea, beleaguered but boundlessly creative. Even though it will take 100,000 years for it to absorb all the carbon we mined from the Earth and loaded into the air, it will be turning it back into shells, coral, and who knows what else. “On the genome level,” notes microbiologist Forest Rohwer, “the difference between coral and us is small. That’s strong molecular evidence that we all come from the same place.”

Within recent historic times, reefs swarmed with 800-pound groupers, codfish could be dipped from the sea by lowering baskets, and oysters filtered all the water in Chesapeake Bay every three days. The planet’s shores teemed with millions of manatees, seals, and walruses. Then, within a pair of centuries, coral reefs were flattened and sea-grass beds were scraped bare, the New Jersey-sized dead zone appeared off the mouth of the Mississippi, and the world’s cod collapsed.

Yet despite mechanized overharvesting, satellite fish-trackers, nitrate flooding, and prolonged butchery of sea mammals, the ocean is still bigger than we are. Since prehistoric man had no way to pursue them, it’s the one place on Earth besides Africa where big creatures eluded the intercontinental megafaunal extinction. “The great majority of sea species are badly depleted,” says Jeremy Jackson, “but they still exist. If people actually went away, most could recover.”

Even, he adds, if global warming or ultraviolet radiation bleaches Kingman and Australia’s Great Barrier Reef to death, “they’re only 7,000 years old. All these reefs were knocked back over and over by the ice ages, and had to form again. If the Earth keeps getting warmer, new reefs will appear farther to the north and south. The world has always changed. It’s not a constant place.”

Nine-hundred miles northwest of Palmyra, the next visible turquoise-ringed smudge of land rising from the blue Pacific depths is Johnston Atoll. Like Palmyra, it was once a U.S. seaplane base, but in the 1950s it became a Thor missile nuclear test range. Twelve thermonuclear warheads were exploded here; one that failed scattered plutonium debris over the island. Later, after tons of irradiated soil, contaminated coral, and plutonium were “decommissioned” into a landfill, Johnston became a post-Cold War chemical-weapons incineration site.

Until it closed in 2004, sarin nerve gas from Russia and East Germany, along with Agent Orange, PCBs, PAHs, and dioxins from the United States, were burned there. Barely one square mile, Johnston Atoll is a marine Chernobyl and Rocky Mountain Arsenal rolled into one—and like the latter, its latest incarnation is as a U.S. National Wildlife Refuge.

Divers there report seeing angelfish with herringbone chevrons on one side and something resembling a cubist nightmare on the other. Yet, despite this genetic jumble, Johnston Atoll is not a wasteland. The coral seems reasonably healthy, thus far weathering—or perhaps inured to—temperature creep. Even monk seals have joined the tropicbirds and boobies nesting there. At Johnston Atoll, as at Chernobyl, the worst insults we hurl at nature may stagger it, but nowhere as severely as our overindulged lifestyle.

One day, perhaps, we will learn to control our appetites, or our duplication rates. But suppose that before we do, something implausible swoops in to do that for us. In just decades, with no new chlorine and bromine leaking skyward, the ozone layer would replenish and ultraviolet levels subside. Within a few centuries, as most of our excess industrial CO2 dissipated, the atmosphere and shallows would cool. Heavy metals and toxins would dilute and gradually flush from the system. After PCBs and plastic fibers recycled a few thousand or million times, anything truly intractable would end up buried, to one day be metamorphosed or subsumed into the planet’s mantle.

Long before that—in far less time than it took us to run out of codfish and passenger pigeons—every dam on Earth would silt up and spill over. Rivers would again carry nutrients to the sea, where most life would still be, as it was long before we vertebrates first crawled onto these shores.

Eventually, we’d try that again. Our world would start over.