Estes
It was about that time that a graduate student fresh out of Washington State University was flunking his military physical. James A. Estes was a young man with a new master’s degree in zoology and a sense of resignation that he would soon be stowing it indefinitely for a tour of combat in Vietnam. At the qualifying physical, the examining doctor sailed through the procedure, then in closing probed Estes for any unseen problems. Once a promising pitcher in college, Estes casually mentioned the shoulder that had given out and ruined his fastball.
Anything else? asked the physician.
Well, there’s this knee that tends to pop.
Can you show me?
Estes shrugged and tweaked the knee, detonating a minor explosion.
“The doctor’s eyes went big,” said Estes, “and that was it. He rejected me right there.”
And so the slim young man with the bum shoulder and trick knee suddenly found himself with the unanticipated freedom to do whatever he wanted with the rest of his life. At which time the phone rang, with news from a former professor about some island called Amchitka.
The island had been a strategic outpost in the North Pacific theater of World War II. And in the cold war that followed, there had sprung up a bustling little enclave of barracks and trailers, hard hats and physicists of the Atomic Energy Commission, preparing to test the island’s reaction to a series of underground nuclear explosions, the biggest of which was to produce four hundred times the power of the Hiroshima blast. The testing included an environmental branch of operations. And from that branch, there was some money and an opportunity for researching something or other about sea otters, with which Amchitka by this time once again abounded. Any interest?
Estes was soon thereafter packing for the North Pacific. He had established his academic base camp as a Ph.D. candidate at the University of Arizona. (Arizona might have seemed a long way from the Aleutians, thought Estes, but then again, where on Earth wasn’t?) And in 1970, with his marine biology résumé consisting of little more than a fondness for fishing and a tendency for seasickness, he shipped off to one of the most alien shores this side of Vietnam to study sea otters.
Up to that point, almost everything Estes knew about the Aleutian sea otter had come from a single definitive monograph published only the year before by a federal wildlife biologist named Karl W. Kenyon. Kenyon had spent a decade watching otters from the bays and rocky promontories of Amchitka Island. He’d noted the daily schedules of these creatures of habit, of busy mornings and late afternoons spent diving for food, gathering mussels and urchins and fish from the rocky bottoms, interspersed with afternoon naps and bouts of fastidious grooming.
The sea otter is the largest and most seaworthy member of the carnivore family of weasels and badgers called the Mustelidae. Nearly as supple as a seal in the water (and with its enormous webbed feet, nearly as clumsy on land), the otter dives with an undulating body propelling it mermaid fashion to bottom depths as great as eighty feet. In dives averaging a minute to ninety seconds, the hunting otter gathers as it goes, grabbing prey with its forepaws, stuffing its baggy armpits full of food, then popping to the surface to set the table. On its chest the otter places its urchin—or mussel or fish or any of the 150 species of prey on its menu—and begins eating. If a shell is too tough to bite through, the otter pulls a rock from its stash, props it upon its chest as an anvil, and with its paws hammers the shell into submission. Sea otters tend to eat whatever comes most readily, an otherwise intuitive habit that would come to bear greater significance in matters of ecology.
Touching down on the runway of Amchitka, Estes wondered just what he had gotten himself into. Amchitka arose as a spike of rock in the far western reaches of the Aleutian archipelago, near the end of a twelve-hundred-mile volcanic arc thrusting like an elephant’s tusk from the Alaska Peninsula toward Siberia. For one raised in the sunny chaparral suburbs of San Diego, the gray, gale-whipped waste of the Bering Sea was the scariest place imaginable. And what about those odd, aquatic carnivores, those eighty-pound sea weasels Estes was supposed to make sense of? Maybe he’d research something about their natural history, or their ecology—perhaps connecting them somehow with their coastal ecosystem might be an interesting thing to do. Sea otters seemed like a cool thing to study, thought Estes, and that was about it.
Estes spent much of the next year acquainting himself with his subjects, netting and tagging and following the sea otters of Amchitka, to what end he still wasn’t sure. He started scuba diving to get a better look at where the otters spent a good part of their lives. What he saw confirmed much of what Kenyon had surmised before him: that otters floated and dove, slept and mated and died among the marine forests of kelp rooted in the cold coastal waters. Estes knew the otters had a catholic diet, but that many had a particular fondness for sea urchins. Otters, urchins, and kelp. He had no idea how they all might fit together. He wasn’t yet sure what his question was. He wasn’t aware that half an ocean away, in a crucible of ecological discovery called Mukkaw Bay, another scientist was busy formulating the question for him.
The Godfather
By the late 1960s, Bob Paine was off and running on the rocky shores of Washington. With his landmark study linking the predations of Pisaster to the intertidal diversity of species, Paine had realized in Mukkaw Bay a perfect little laboratory for asking some of the biggest questions of ecology. The splash zones and tide pools of the rocky outer coast offered a dynamic universe of predator and prey in a fishbowl, which Paine and his lengthening list of student protégés could poke and prod and manipulate as they pleased. There were neither rare nor endangered species to tiptoe around. In this Lilliputian kingdom there was no creature so fleet or fierce as to run away in the middle of an experiment, or rear up and maul the probing naturalist. Nobody cared if Paine drilled survey stakes that would benchmark a study plot for decades. If for experimental purposes he needed a new tide pool, he could jackhammer one. Nobody would object if, in the name of science, he pried a whole galaxy of starfish from a wave-beaten rock and flung them into some other orbit.
And if, say, Paine might be curious to see what would happen if he plucked all the sea urchins from a particular tide pool, what was to stop him? So Paine, master of his universe, did so. Along with student Robert Vadas, Paine exercised his godly powers on an ecosystem dominated by Strongylocentrotus purpureus, the purple sea urchin. The urchins are globular, spiny cousins to the starfish, centered underside with a circular jaw used for grazing kelps and other algae off the bottom. They are to ribbons of kelp as the starfish are to mussels. When Paine had first peered into the tide pools of Mukkaw Bay, many had been cobbled solid with sea urchins, the kelp hardly to be seen. Within a year of he and Vadas playing predator to the urchins, the once neatly shorn pools had converted to solid jungles of fleshy kelp.
The resulting paper, a minor classic in Paine’s growing canon, presented yet another stark example of an animal’s consuming potential to upend an ecosystem. This was Paine’s forte, a knack for drawing grand panoramas from intimate little portraits of life. The discovery that a sea urchin could obliterate a tide pool of kelp was maybe not as newsworthy as that of an earth-bound asteroid. But then again, kelp was something more than just seaweed.
Kelp is a generic term for a suite of brown algae species that dominate the rocky shallows of the world’s cold-water coasts. When washed up on the beach, they are those familiar squishy, translucent brown straps of lasagna pasta, pecked about by the crabs and gulls. When attached in living colonies to the seafloor, kelp is a different animal, a lush and leafy marine forest. The giant kelp Macrocystis pyrifera, the sequoia of the kelp forest, can grow nearly two feet in a day, topping out at almost two hundred feet. Within the kelp forests congregate masses of marine life, from sea squirts to sea lions. Its photosynthetic flesh provides pasture for the swimming herbivores, its dead fronds fall as detritus for the bottom-scrapers. Its physical presence—its roots and trunks, its spreading canopy
of fronds—is a scaffolding for life in an otherwise gripless realm of open water. For its unparalleled productivity and physical stature, the community of kelp has been seen by more than one ecologist as the marine analogue to the terrestrial rainforest.
“The number of living creatures of all orders, whose existence intimately depends on the kelp, is wonderful… I can only compare these great aquatic forests of the southern hemisphere with the terrestrial ones in the intertropical regions,” wrote the young Charles Darwin on June 1, 1834, while passing through Tierra del Fuego on his five-year voyage aboard the H.M.S. Beagle. “Yet if the latter should be destroyed in any country, I do not believe nearly so many species of animals would perish as, under similar circumstances, would happen with the kelp. Amidst the leaves of this plant numerous species of fish live, which nowhere else would find food or shelter; with their destruction the many cormorants, divers, and other fishing birds, the otters, seals, and porpoises, would soon perish also; and lastly, the Fuegian savage … would … perhaps cease to exist.”
Kelp was important, and urchins ate kelp. That much Paine had come to understand when, in the summer of 1971, faculty heads at the University of Washington sent their emergent star of intertidal ecology on an Aleutian junket. Paine was to pay an advisory visit to some UW graduate students then poking about the kelp forests far off on the island of Amchitka. One of those students was John Palmisano, who alerted his colleague from the University of Arizona that there was a terrific ecologist on the way. You really ought to meet him, Palmisano told Estes.
A Summit of Two
There’s a small disagreement between Estes and Paine about where they actually met. Estes says it was waiting for a movie to start at the Amchitka gymnasium. Paine thinks it was in a bar. Whichever the venue, the ensuing chat inarguably altered Estes’s life.
Estes was intimidated by this towering figure of science, articulating in bold, baritone clips of plainspoken English his views on how the world of nature worked. But Paine turned out to be an enthusiastic listener as well, sitting attentively as Estes offered his study plans. He listened until Estes finished explaining that he thought it might be instructive to show how the kelp forest supported its sea otters—ecology’s conventional bottom-up line of inquiry.
“Jim, that’s stupid,” Paine said.
And in an act of big-brotherly affection, Paine flipped Estes on his head, conceptually speaking. “Jim, there’s something vastly more interesting. You’re sitting on a gold mine of interaction. You want to work on otters eating sea urchins, and sea urchins eating kelp,” declared Paine, punctuating his advice with references to a certain paper recently authored by Paine and Vadas, verifying the urchin-kelp connection. Paine had seen what urchins could do to a community of kelp when left unchecked. And sea otters ate sea urchins, that much Estes certainly knew. Here, then, said Paine, was a ready-made experiment of predation on an oceanic scale, a checkerboard chain of islands, some with sea otters and some without (compliments of the fur hunters), waiting for somebody to take its measure.
Estes didn’t remember much of the movie, dizzy as he was from having his worldview turned upside down, compliments of Robert T. Paine.
Shemya
The idea was to go to another place with all the ecological qualities of Amchitka, but lacking otters, and compare the two: Go underwater, count urchins, measure the kelp, and note any differences the sea otter made. If one could just see any significant changes in urchins, thought Estes, that would be exciting enough.
Shemya was the first choice. Closer to Siberia than America, Shemya was six square miles of rock protruding more than two hundred miles to the west of Amchitka. Shemya, like Amchitka, had a lingering military presence, with an air force base and a runway. It had but a small pocket of otters that had managed to recolonize since the great extermination. The rest of the island would provide the counterpoint to the otter-laden Amchitka.
In 1971, Estes and three colleagues arranged a reconnaissance, chartered a flight, flew the gap from Amchitka, and spent their first half day in Shemya under house arrest. There they stayed until the commanding officer finally softened to the idea that the four young hippie types appearing before him from out of the Pacific blue were not spies. Upon release, the reinstated biologists wandered down to preview the beach where they were to begin their surveys the next day.
The first things Estes noticed were the sea urchins. Their skeletons littered the shore. He had never seen such big urchins at Amchitka. But here lay monsters, huge urchins four to five inches across, piled in green windrows at the high-water mark. This was something radically different. That night, Estes declared to his research mates, “We’re going to see something cool here.”
The next day they took a boat out onto the reef. Estes donned his wet suit and dove underwater, into a moment forever crystallized in his mind. “Because there it was,” he said, “just this green carpet of sea urchins everywhere. And no kelp. And boom, that did it. It took me about a nanosecond to connect on what was going on with otters and the kelp forest system, and how important they were.”
Here was a seascape that had been mowed to the nub—the antithesis of the Amchitka kelp jungles. And the only apparent difference was the sea otter. The most fertile ecosystem across the North Pacific coast was denuded for lack of otters. If what Estes had seen held true across the board, then the foundation of this coastal food chain was ultimately governed from above, by an adorable, urchin-munching carnivore.
Back at the barracks that night, Estes sat awake with his journal, writing and writing, frantically until dawn. Scraps of thought and observation bubbled up, gathering like magnetic filings into a pattern of life in the kelp forest. Otters to urchins to kelp, a chain of ecological percussion and repercussion, transforming an undersea world. Estes hurried to capture these ideas. He didn’t dare chance that they’d abandon him in his sleep.
That one moment at Shemya had lifted the last of the fog. Estes now knew exactly his path. He set about measuring the sea otter’s impact with scientific precision.
Each day, he and Palmisano would either wade from shore or head out in the skiff and then dive to the bottom of the reef, counting sea urchins and estimating the coverage of kelp. To Shemya’s study they later added the otterless island of Attu, thirty-five miles farther out on the tip of the Aleutian chain.
Their data did not come cheaply. The two typically headed out into the Aleutians’ notoriously deadly waters whipped by tireless gales blowing fifty knots. On days when even the locals hunkered on shore, Estes and Palmisano were out on the high seas. And Estes, the diver, was in the water. He dove both summer and winter. In the winter the waters averaged thirty-five degrees Fahrenheit; in the summer they warmed to forty-five. Estes would dive in the morning for an hour, collecting samples of kelp and urchins, staring into square-meter quadrates, filling data sheets with names and numbers. He would write underwater on slates until his chilled hands were shaking too violently to continue. After a hot shower to thaw the blood, he would head out again in the afternoon for another hour, until he was too numb to write anything more. The next day he would repeat the process.
It was the scientific way of objectively confirming what the eye could not deny. Estes and Palmisano had watched the defining event thousands of times at Amchitka: sea otters, lying in the water, bellies to the sky, urchins between the paws, rolling them like little balls of dough to flatten the spines, and popping them down the hatch like popcorn, one after the other. The inquiring scientist didn’t need to sift through buckets of sea otter scat, didn’t need to slice into stomachs to know what the otters were eating. And it only took a minute underwater to confirm the ecological consequences.
Wherever they looked, the pattern held true. On the otter-patrolled reefs of Amchitka there were forests of brown kelp, with fish swimming among the rising fronds, and a colorful diversity of sponges and hydrocorals, mussels and barnacles populating the seafloor. In the otterless reefs of Shemya and Attu the seaflo
or had been reduced to a pavement of pink coralline algae, pocked with spiny green blobs of enormous sea urchins. If Amchitka was a kelp jungle, Shemya and Attu were urchin barrens. It was every bit as obvious and dramatic as stepping from a towering ancient forest into clear-cut. And the sea otter remained the difference.
As obvious as it might have seemed—after all, it was no secret that otters ate urchins, that urchins ate kelp—still nobody before Estes had connected the first to the last. Karl Kenyon, in his decade with the Amchitka otters, had come close. “Indirect evidence from Amchitka Island, where a large sea otter population exists, indicates that sea otter predation has drastically reduced certain food species there,” Kenyon wrote in his 1969 monograph. “Small green sea urchins are abundant. It is not possible, however, to find large individuals in the intertidal zone and I seldom saw an otter eating an urchin that approached in size the large individuals which are abundant in other Aleutian areas where the sea otter is scarce or absent.” Kenyon, who did not dive, never mentioned the kelp.
By the end of their second summer of diving, Estes and Palmisano had the data and the confidence to go public with their findings. The two spent a week writing up the manuscript. Estes wasn’t sure anybody would be interested, but Palmisano suspected otherwise and insisted they send their manuscript to the journal science. And in September 1974, the most prestigious of scientific publications pictured Estes and Palmisano’s sea otter on its cover.
Estes, who a few weeks before had been just another grad student wondering how he was going to survive in the world, was suddenly entertaining University of Arizona faculty who’d never before said a word to him, now asking for reprints. Letters came from afar. Professors had a different look on their faces when they passed Estes in the halls. Even the modest mind knew that this discovery was a big deal.
Where the Wild Things Were Page 7