Finally, some good news out of Antarctica for one penguin species threatened by climate change.
Biologists have been watching with dread a steady decline of what they thought was a dwindling population of the small bodied and widespread Adélie Penguins. But today, a new study led by researchers from the Woods Hole Oceanographic Institution and published in the journal Scientific Reports, “announced the discovery of a previously unknown "supercolony" of more than 1,500,000 Adélie Penguins in the Danger Islands, a chain of remote, rocky islands off of the Antarctic Peninsula’s northern tip”.
The Adélie requires sea ice for the entirety of it’s life, but they only breed and raise their chicks on ice-free land. There is very little ice free land, only 1 percent of the land area on the continent is ice free.
"Not only do the Danger Islands hold the largest population of Adélie penguins on the Antarctic Peninsula, they also appear to have not suffered the population declines found along the western side of Antarctic Peninsula that are associated with recent climate change," says Polito.
Being able to get an accurate count of the birds in this supercolony offers a valuable benchmark for future change, as well, notes Jenouvrier. "The population of Adélies on the east side of the Antarctic Peninsula is different from what we see on the west side, for example. We want to understand why. Is it linked to the extended sea ice condition over there? Food availability? That’s something we don’t know," she says.
It will also lend valuable evidence for supporting proposed Marine Protected Areas (MPAs) near the Antarctic Peninsula, adds Mercedes Santos, from the Instituto Antártico Argentino (who is not affiliated with this study but is one of the authors of the MPA proposal) with the Commission for the Conservation of the Antarctic Marine Living Resources, an international panel that decides on the placement of MPAs. "Given that MPA proposals are based in the best available science, this publication helps to highlight the importance of this area for protection," she says.
National Geographic expands on the study by noting what is currently known about climate change impacts on the Adélie population.
Of the Antarctic Peninsula’s three types of penguins—Adélies, chinstraps, and gentoos—Adélies are the only solely Antarctic species, and they require Antarctic conditions.
But along the Antarctica Peninsula’s western side, seas have gotten hotter in the past 40 years, and winter air temperatures there have increased about nine degrees Fahrenheit. Sea ice-free seasons have lengthened by up to three months; nearly 600 of the region’s 674 glaciers are in retreat.
The shifting conditions have altered the area’s food web, changing when and where Adélies can eat. The extra warmth also means extra rain, which floods or destroys penguin nests, drowns eggs, and causes chicks to literally freeze to death. The result: nearly every Adélie colony along the western peninsula is in decline.
On the eastern Antarctica Peninsula and the Danger Islands, however, Adélies thrive. Here, winds push ice up and around the tip of the peninsula, and a slowly churning vortex of seawater pins it against land. As a result, sea ice lasts far longer, making the area friendlier for Adélies.