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As the Antarctic ice melts, 800-year-old penguins are exposed



Cape Irizar on the Ross Sea in Antarctica.

Cape Irizar on the Ross Sea in Antarctica.
image:: Steven Emslie

A biologist working off the Ross Sea in Antarctica has come across a number of Adélie penguin remains, some of which appear to have died recently. It turns out that these dead penguins are actually quite old and have been re-exposed by the effects of global warming.

Four years ago, the biologist Steven Emslie was scouring the Antarctic coast at Cape Irizar of the Ross Sea when he came across the remains of Adélie penguins. He recognized them as such, not by their appearance, but by the unusual number of pebbles in the area from which these penguins build nests. Many of the penguin carcasses, most of them chicks, appeared degraded and quite old, but some looked like they had recently died.

It did not seem possible for Emslie that the remains of recently deceased Adélie penguins could be found at Cape Irizar. Today the Ross Sea is home to nearly 1 million breeding pairs of Adélie penguins, but no active penguin colony has been observed at this site since it was discovered by British explorer Robert Falcon Scott in the early 20th century.

As he explored the area further, Emslie found a jumble of penguin bones on the surface, but also chick carcasses still covered in feathers. The level of degradation observed in these chicks was consistent with what could be expected from carcasses found in the sites of modern colonies. He also found guano stains, again indicating a recent occupation.

The remains of an old penguin chick whose feathers and tissues are still intact.

The remains of an old penguin chick whose feathers and tissues are still intact.
image:: Steven Emslie.

When Emslie found out that he had found something important, he called his colleagues to the place where they extracted samples from the pebble mounds. As he in a statement His team, published by the Geological Society of America, “dug in three of these mounds using methods similar to archaeologists to extract preserved tissue from penguin bones, feathers and eggshells, and hard parts of the prey from the guano.” Emslie said, the ground is “very dry and dusty, as I have found in other very old places where I worked in the Ross Sea,” which also produced a large number of penguin remains.

Radiocarbon dating of the remains confirmed Emslie’s suspicion – that the remains must be very old despite their fresh appearance. What he didn’t expect was how old.

The results showed that “the remains are indeed ancient and represent three periods of occupation by Adélie penguins,” the oldest of which were formed around 5,000 years ago, while the most recent occupation ended around 800 years ago paper published in the journal Geology.

“In all the years I’ve done this research in Antarctica, I’ve never seen a website like this,” Emslie said in the statement.

    Adélie penguin bones on the surface and a selection of pebbles that the birds used to build nests.

Adélie penguin bones on the surface and a selection of pebbles that the birds used to build nests.
image:: Steven Emslie

Emslie said conditions for the penguins were ideal 4,000 to 2,000 years ago, as it was a warm period of “increased marine productivity.” Eventually, however, each of the three documented occupations ended, likely due to increased snow cover over the cape or sea ice ingress due to cooling temperatures. Penguins caught at the end of their occupation left bodies covered in snow and ice, and have preserved them until now.

These old dead penguins have recently poked through snow and ice, which explains their fresh appearance. Unsurprisingly, Emslie, the only author on the paper, said this could be attributed to climate change. As the paper points out, the annual temperature in the Ross Sea has increased 2.7 to 3.6 degrees Fahrenheit (1.5 to 2 Centigrade) Since the 1980s, satellite imagery of the area captured since 2013 has shown that the rocky cape becomes increasingly visible as the snow and ice melt.

Climate change has led to some Interesting Scientific discoveries lately, but the dire reality is that all of this warming is ready to do more damage as well when it comes to studying the past.


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