.jpg "NATIONAL GEOGRAPHIC")
.jpg "NATIONAL GEOGRAPHIC")
Little auks returning from sea to nest after feeding on copepods.
PHOTOGRAPH BY PAUL NICKLEN, NATIONAL GEOGRAPHIC
PUBLISHED JANUARY 12, 2015
What's New: The latest research on little auks, sometimes called "penguins of the north," reveals a surprising response to a rapidly warming Arctic: The birds make up for food lost to the effects of climate change by catching prey that were stunned by the cold water running off melting glaciers—another effect of climate change.
The study, published Monday in the journal Global Change Biology, is the first to examine the feeding habits of little auks as Arctic ice is lost. Scientists watched the birds in Franz-Josef Land, off the northern coast of Russia, during an expedition supported by the National Geographic Society.
Since 2005, the auks' water has become essentially ice-free in summer, reducing the numbers of tiny animals known as zooplankton, a key food source for the auks. Zooplankton normally congregated around sea ice, but now the birds have shifted to eating zooplankton that are stunned—and thus easier to catch—by cold water running off glaciers melting on land. (See photos from the expedition.)
The shift hasn't been entirely seamless. Little auk chicks have been growing just as quickly as they did before 2005, but the adults' body mass has dropped an average of 4 percent since the early 1990s. That might not sound like much, but "we don't know what the weight loss is that would really harm them," says Enric Sala, a co-author of the study and a National Geographic explorer-in-residence.
Little auks return to land in the Arctic, after feeding on plankton at sea.
Why It Matters: Little auks are considered especially vulnerable to climate change. The birds are often considered an indicator species of the Arctic, raising red flags for ecological changes.
"It's good news that the little auks are adapting now," Sala says, "but because the system is changing continuously, we don't know how long they will be able to keep up."
The birds also play an important role in the Arctic ecosystem, so other species could be affected by changes in little auks. (Learn about big waves forming in an ice-free Arctic.)
The Big Picture: To date, the Arctic has warmed twice as fast as lower latitudes have. The Arctic will be essentially free of summer sea ice by the 2030s, with drastic implications for species from seabirds to polar bears, according to the Intergovernmental Panel on Climate Change. (Similar forces are at work around Antarctica.)
Some Arctic species may go extinct, scientists have warned, but precisely how individual species will respond is largely unknown and will probably hold some surprises, as this new paper suggests.
What's Next: The scientists estimate that all continental glaciers will disappear from Franz-Josef Land within about 180 years, although meltwater could decrease significantly before that. As that happens, it's unclear if the birds will be able to find enough food.
"Ultimately, there is only one thing we can do for little auks, polar bears, and everything else that is affected," says Sala. "That's to reduce emissions of greenhouse gases."