Penguins

Where on Earth, wondered Henri Weimerskirch, were all the penguins? It was early 2017. Colleagues had sent the seabird ecologist aerial photos of Île aux Cochons, a barren volcanic island halfway between Madagascar and Antarctica that humans rarely visit. The images revealed vast areas of bare rock that, just a few decades before, had been crowded with some 500,000 pairs of nesting king penguins and their chicks. It appeared that the colony—the world’s largest king penguin aggregation and the second biggest colony of any of the 18 penguin species—had shrunk by 90%. Nearly 900,000 of the regal, meter-high, black, white, and orange birds had disappeared without a trace. “It was really incredible, completely unexpected,” recalls Weimerskirch, who works at the French national research agency CNRS.Soon, he and other scientists were planning an expedition to the island—the first in 37 years, and only the third ever—to search for explanations. “We had to go see for ourselves,” says CNRS ecologist Charles Bost.As the researchers prepared for the journey, they had to grapple with the logistical, political, and scientific challenges that have long bedeviled biologists trying to understand Antarctica’s remote ecosystems. The vast distances, rough weather, and rugged terrain make travel difficult and expensive. They needed a ship—and a helicopter, because frigid seas and rocky shores make for perilous boat landings on Antarctic islands. Complying with the tough permitting and biosecurity rules governing the French-controlled island—meant to prevent researchers from disturbing fragile ecosystems—required careful planning and paperwork that took months to complete. And once they arrived, they would have precious little time: just 5 days to investigate a multitude of suspects in the disappearance, including disease, predators, and a warming Southern Ocean.In all likelihood, they would never be able to return. “We knew this was going to be a one-shot expedition,” recalls conservation biologist Adrien Chaigne, an expedition organizer who works for the National Nature Reserve of the French Southern and Antarctic Territories, which manages the island. “It was a real kind of pressure.”

have long faced biologists seeking to understand life at the remote bottom of the planet. Two centuries ago, researchers wanting to visit the region had to tag along with explorers, whalers, or seal hunters. The Adélie penguin, for example, was first identified by a naturalist who joined an 1837 expedition to southeastern Antarctica led by the French explorer Jules Dumont d’Urville, who named the place Terre Adélie after his wife. The harrowing  voyages rewarded them with surprises: In 1895, botanists certain no plant could survive the frigid Antarctic were shocked to discover lichens on Possession Island, near Île aux Cochons.

But even today, Antarctic research is challenging. “If it takes you 2 hours to collect samples back home, it could take 10 in Antarctica,” Karentz says. Holes drilled in sea ice to collect samples, for example, often need poking to remain open. The harsh conditions can claim valuable gear. In 1987, shifting sea ice swept away a plexiglass frame Karentz was using to study microorganisms beneath the surface. She scrambled to replace it with materials scrounged from a nearby research station. In Antarctica, she says, “You have to be resourceful.”weren’t lost on Weimerskirch and Bost, both veterans of Antarctic research, when a helicopter from the Marion Dufresne, a French research vessel, delivered the penguin researchers and their 700 kilograms of gear to Île aux Cochons in November 2019. It was the middle of king penguin nesting season, and they were greeted by the raucous honking and chirping of tens of thousands of chicks. They also saw vast empty swaths of bedrock, where previous generations of birds had scraped away the soil. The scientists estimate penguins once stood flipper to flipper on some 67 square kilometers of ground that is now abandoned.The researchers were eager to find out what had caused those losses. King penguins, numbering 3.2 million birds in the Antarctic region, aren’t in immediate danger; in fact their numbers are mostly rebounding from centuries of human hunting. By contrast, half the world’s penguin species are threatened (see graphic), and several have recently experienced disturbing die-offs. But big losses of even relatively healthy species could point to broader threats, which is why the calamity on Île aux Cochons triggered alarm bells.

Today, modern research budgets and a network of polar research stations have made Antarctica more accessible. Biologists have flocked to the region to tackle an array of fundamental questions, including how animals evolved to survive subzero temperatures and how ecosystems are organized in the vast, productive Southern Ocean. Climate change, which has made the Antarctic one of the fastest changing places on Earth, has inspired studies of shifting ice and acidifying seas. The potential for discovery makes the region addictive, says marine biologist Deneb Karentz of the University of San Francisco. “Once you go as a scientist you always want to go back.”