Age-old Arctic plants uncovered by retreating glaciers

Moss and lichen uncovered by shrinking icecaps may be up to 115,000 years old

Glaciers of eastern Baffin Island, Nunavut

Simon Pendleton and Gifford Miller collect moss from an icecap on eastern Baffin Island. The American climate change researchers say the plants they gathered in Nunavut could be 115,000 years old. (Photo courtesy of Simon Pendleton)

By Beth Brown

Glaciers melting rapidly on Baffin Island are uncovering Arctic landscapes not seen in over 40,000 years—and possibly much longer.

That’s according to a recent study published in the journal Nature Communications, by a group of American scientists who spent three summers surveying ice caps on eastern Baffin Island around the Cumberland Peninsula.

“It’s very apparent that the glaciers are retreating rapidly,” said lead researcher and study co-author Simon Pendleton of the Institute of Arctic and Alpine Research at the University of Colorado Boulder.

To figure out how old these uncovered landscapes are, Pendleton and his team gathered 48 samples of plants from 30 ice caps near the Penny Ice Cap.

“We often think of glaciers as erosive,” Pendleton said. “These ice caps freeze to the bed and they don’t slide so they preserve the landscape underneath.”

That’s how, when the glaciers recede, northern plants like lichen or moss are left in the exact spot where they were growing when they were covered by ice. It’s also why plants can be used as a tool to study past glacial activity, Pendleton said.

By finding out how old the plants at the edge of the glaciers are, researchers could figure out when ice last started covering the landscapes.

“These landscapes that are just now being uncovered by retreating ice margins have been covered for at least the last 40,000 years,” Pendleton said.

The researchers found this through a method called radiocarbon dating.

The thing is, carbon dating is only really effective for dating material that is up to about 40,000 years old, so the plants could be much older. And they probably are, because 40,000 years ago the northern hemisphere was in a deep glacial period, Pendleton said, so it’s likely these plants were encased in ice back then.

To take a guess at just how old the plants are, Pendleton and his team looked at temperature records taken from ice core samples around Greenland.

They found that if you look back 40,000 years, and then keep looking back—it hasn’t been warm enough to see plant life around the Penny Ice Cap in 115,000 years.

That was during what is called an interglacial period, or, “the time between glacial periods,” Pendleton said.

If you visit the ice caps around Cumberland Peninsula now—close to Qikiqtarjuaq—you can see each summer how the glaciers are receding, metres at a time, Pendleton said.

“It’s profound. It gives you a real sense of the change that is occurring in the Arctic today,” he said.

The scientists did this field research in August, when the glaciers were at their warmest during the year.

The study uses data gathered in 2013, 2014 and 2015.

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(6) Comments:

  1. Posted by Sam on

    Therefore, wouldn’t, this support the theory that global warming happened in the past and probably is a cycle every so many hundred years?

    • Posted by Cb on

      There is no question that the planet goes through cyclical climactic regimes. The current predicament we’re in is that the rate of temperature change we’re currently witnessing is likely much greater than what has occurred in the past. If unchecked/uncontrolled and given it’s relatively quick occurrence (evolutionarily speaking), this will not bode well for the biological systems we depend on and may result in our extinction…

    • Posted by Putuguk on

      There is a petrified forest on Axel Heiberg Island, fossils of reptiles and giant beavers up there too. The climate has been generally warmer in the past plenty of times.

      Difference today is that there are billions of human beings depending on the climate staying the same in order to support our lives.

      In the same way, I can say that there is traffic on my street. It is a pretty obvious thing. Only a deranged person would ignore the trucks and snowmobiles.

      We are free to argue on when traffic started, how often there is traffic, what kind of vehicles, how fast they are, if there is more traffic, who is in charge of traffic, how to safely cross the street, or when the next vehicle will come by.

      There are experts and idiots alike that will have opinions either way on any of these topics.

      However, If a person happens to walk out on the street at the moment a truck goes by, they will get run over ending up mangled and dead.

      We are now stepping off into traffic.

  2. Posted by hugh macisaac on

    Are any of the spores from the lichen apothecium with spores viable?

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