August 17, 2013 — The keystone of the South Georgia ecosystem, the secret to the miraculous abundance of wildlife on this stark, cold, windswept island—the foundation, indeed, for almost all vertebrate life in the Antarctic—is krill.
On the Antarctic island of South Georgia, in February, toward the middle of what passes for summer at the bottom of the world, I hurried through the ruined whaling station of Grytviken.
I had an appointment at the British Antarctic Survey station on the opposite side of King Edward Cove. I was to interview a marine ecologist working on krill. I did not want to be late.
The keystone of the South Georgia ecosystem, the secret to the miraculous abundance of wildlife on this stark, cold, windswept island—the foundation, indeed, for almost all vertebrate life in the Antarctic—is krill.
South Georgia and the South Sandwich Islands are administered from the Falkland Islands as a British Overseas Territory, in which the little outpost of Grytviken is the only inhabited spot. The inhabitation is very marginal. In southern winter there are just eight staff members of the British Antarctic Survey, including a doctor, a government officer, and a postal clerk. A handful of visiting scientists augment this skeleton crew in southern summer.
Grytviken is gritty and grim. The name means "Pot Bay," a reference to the cauldrons in which the Norwegian whalers here rendered oil from blubber. It is apt. The rusting vats, boilers, ramps, chimneys, and ramshackle buildings of the long-abandoned whaling station; the wrecks of the catcher boats stranded on the waterfront; and the rows of giant whale-oil tanks upslope are all the apparatus of a genocide, in the literal, Latin sense of the word. The genus was Balaenoptera, the baleen whale.
From the whale's upper jaw, in place of teeth, hang long, fringed curtains of keratin—baleen—used to seine krill. The largest member of the genus and the biggest creature ever to live, the blue whale gets that way from its ability to process eight tons of krill a day.
The Antarctic, in its remoteness, girded by pack ice, abloom in summer with phytoplankton and coursing with torrents of krill, was the stronghold of the blue whale. The invention of the steam-powered catcher boat and the explosive harpoon ended all that. Today in the Southern Ocean, where a century ago 200,000 blue whales fed on the krill swarms of austral summer, only a few hundred are left. (Related: "Catching Copepods: Charasmatic Microfauna of the Arctic")
A Game of Chinese Boxes
If William Blake thought he had seen "dark satanic mills" in England, then he should have taken a stroll through Grytviken. After the darkness of the whaling station, and the black, snow-seamed rock of the encircling mountains, and the somber sky, the white interior of the British Antarctic Survey laboratory was dazzling.
For a moment I lost my bearings. Bright fluorescent light glinted from microscopes. Martin Collins turned away on a swivel stool from his laboratory workbench and stood to greet me. In his immaculate white lab coat he was incandescent, an angelic figure of medium height, pale-skinned, with semi-curly hair of indeterminate color. This might have been the start of the Rapture, with Collins as my heavenly guide—until I chanced to glance down. Beneath his white lab coat the ecologist was wearing muddy trousers and gumboots streaked with penguin guano.
He mimed an apology for not shaking hands, holding up both of his own to show blue rubber gloves. Just now he had been rooting around in fish stomachs. Pulling over a bucket of offal, he groped about inside and extracted a half-digested mackerel icefish. "That's come out of a skate's stomach," he said.
"A little worse for wear," I suggested.
Collins agreed and he dug again in the offal, searching for a more intact specimen. His bucket of guts was bloody, but not in the normal, crimson sense, for icefish have no hemoglobin. Their plasma is full of antifreeze but no red cells, so their blood runs clear.
"This one's probably slightly better," he said, holding up a less eroded fish. "There's a fishery for these mackerel icefish. We've done a trawl survey for icefish all around South Georgia to estimate the stocks. Icefish are krill feeders—80 percent of their diet is normally krill—so their stomachs can tell us what's happening with krill. I've done something like 650 icefish in the last couple of weeks. It's been a slightly strange year for the krill around South Georgia."
"Strange," I said. "In what way?"
"You get odd years, and 2004 was one of those, when there's a little bit less krill. This year seems to be fairly extreme. There's very little krill and scarcely any icefish at all. We're seeing the gentoo penguins struggling a little bit this season, as well. Not enough krill. The gentoos don't seem to be giving the food to their chicks that they normally do."
From his workbench Collins retrieved a glass dish of krill. He had extracted this handful—eight or nine little shrimplike crustaceans—from the stomach of an icefish, which he had previously extracted from the stomach of a skate, and had counted, weighed, and measured each one.
In death the krill were bright red. They were big Euphausia superba, the king of krill, probably the most successful species on Earth by measure of sheer biomass: roughly twice the weight of humanity, thronging in "swarms" as dense as 10,000 individuals per cubic meter.
In Norwegian, kril means "small fry." The noun is almost always a collective plural in that language, as it is in English. And as it is in the grammar of Nature herself, where krill are collective like no other organism. The name has an onomatopoeic rightness; "krill" seems to boil, seethe, swarm.
Collins's game of Chinese boxes—his opening of stomachs to investigate the stomachs within—had ended with this dish of krill. No further dissection was necessary, for krill are translucent, and the green contents of the gastric mill and the hepatopancreas were visible through the exoskeleton. In the middle of krill mating season, the last meal—interrupted by a hungry icefish—for these krill had been phytoplankton.