by INTERSEKT | 19/03/2018 2:29 pm
(NATIONAL GEORGRAPHIC) by Elaina Zachos – Hundreds of millions of years ago, Antarctica was carpeted with prehistoric greenery. Now, scientists may have uncovered clues about what happened in the “Great Dying,” or Permian extinction.
Antarctica is one of the harshest environments on the planet. As the coldest, driest continent, it harbors a world of extremes. The powerful katabatic winds that rush from the polar plateau down the steep, vertical drops around the continent’s coast can stir up turbulent snowstorms lasting days or weeks, and the endlessly barren terrain gives Antarctica the title of the world’s largest desert.
Today, polar summers pound the continent with 24 unforgiving hours of light for about half the year, before polar winters plunge it into complete darkness for the other half. Regardless of the season, the temperatures are consistently below freezing, making treks to the landmass unthinkable for the faint of heart.
But Antarctica wasn’t always like this. Hundreds of millions of years ago, the continent was smushed together with other modern-day landmasses to form the supercontinent Gondwana. Gondwana was humid and carpeted with a network of hardy plants. As the turbulent climate shifted from hot to cold on a sometimes monthly basis, the streamlined foliage would have needed to withstand extremes.
But then, a massive extinction event pulsed through the land. It catapulted nearly all life to an end, obliterating more than 90 percent of the world’s species at the time.
What caused this die-off, called the Permian extinction or the Great Dying, is still shrouded in mystery. Clues to the massacre come to us in the form of fossilized trees, but much of the reasons behind this extinction remain unsolved. And that’s why a handful of intrepid scientists traveled to Antarctica this winter, curious to uncover clues about what led to the end of the continent’s forested past.
“Our goal this year was to study fossil ecosystems around the time of the late Permian,” says Erik Gulbranson, a University of Wisconsin-Milwaukee professor who was one of three team leaders on an expedition to the continent in late 2017. “What we’re able to see in these fossil ecosystems is something we’ve never seen before in Antarctica.”
The team discovered five new fossil forests that would have lived into and beyond the Permian extinction interval. This was the most fossil forests they have found in one season, and it nearly doubles the known fossil forests in Antarctica.
“These new findings tell us how these organisms were reacting or responding to the climatic or environmental changes that were taking place during the extinction crisis,” Gulbranson says. “Having a fossil record of the extinction interval is our only understanding of how life on the planet goes through such an event.”
This work is timely, since many scientists warn that we’re going through an extinction period right now, spurred by human disruptions to natural systems.
What we know about the Permian extinction we know through marine fossils of animals that once lived in the oceans. Many scientists agree that during this period about 299 to 251 million years ago, a volcanic event triggered a crisis that exterminated about 90 percent of all species on the planet. It eradicated more than 95 percent of marine species and more than 70 percent of all land species.
But beyond the broad outlines, a number of the details are unclear. Some geologists and paleontologists say the Permian extinction occurred over 15 million years, but others say it lasted 20,000 years—a blink of an eye in the scheme of geologic time.
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