Melting ice reveals mummified penguins in Antarctica
By Matt Kaplan
In January 2016, Steven Emslie was finishing a season of studying penguin colonies living near Zucchelli Station, an Italian base in Antarctica. With the austral summer quickly coming to a close and all planned work completed, Emslie, an ornithologist at the University of North Carolina, Wilmington, did what any good scientist would do with a few extra days in the Antarctic: He went exploring.
He had heard rumors of penguin guano on a rocky cape along the Scott Coast but knew of no active colonies there.
Emslie immediately knew he had stumbled upon something intriguing when he arrived. “There were pebbles everywhere,” he recalled.
While pebbles are an everyday find on other continents, it is rare to spot them in abundance on dry land in Antarctica. A key exception is found in Adélie penguin colonies, as the birds collect the small stones from the beaches to build their nests.
Then Emslie saw the guano. Then he found the penguin corpses.
With feathers still intact and flesh having barely decayed, Emslie was stunned.
He collected some remains and took them back for carbon-dating analysis to work out when the birds had died.
With dates of death that ranged from 800 to 5,000 years ago, Emslie immediately realized that the guano, feathers, bones and pebbles had all been locked in place under layers of ice for centuries and that the “freshly dead” penguins were in fact recently defrosted mummies that had been swallowed by advancing snow fields long ago.
Emslie speculates in the journal Geology, where he reported his findings in mid-September, that cooling temperatures drove a type of sea ice to form along the coast that persisted well into summer months. Known as “fast ice” because it “fastens” to the coastline, this sea ice makes it very difficult for penguins to gain access to beaches and prevents them from colonizing places where it occurs.
He said he thought the ice forced the colony to be abandoned but also suggested that warming temperatures might change things in the years ahead.
With Antarctic ice melting and sea levels rising, established penguin colonies are being forced to disperse to new places. Emslie suggests that the penguins could then return to sites like this one.
“They need pebbles for their nests, so they are going to find all the pebbles that are already on the land at this site very attractive,” he said.