Under the ice of Antarctica there is an ancient forest of 'resilient' trees

Under the ice of Antarctica the remains of ancient forests. The South Pole has not always been an icy expanse devoid of vegetation. About 260 million years ago, it housed a patchwork of forests. Now scientists have found the fossil remains and are studying them to learn more about our planet's past

Other than icy desert. Millions of years ago, temperatures in Antarctica were milder. We are at the end of the Permian period, before the advent of the dinosaurs and the largest mass extinction event in history.

Many scientists believe a huge increase in greenhouse gases, possibly due to volcanic eruptions in Siberia, caused this extinction, and the University of Wisconsin-Milwaukee team hopes to learn more from the fossils trapped under the ice. Specifically, researchers are currently examining a region called McIntyre Promontory in the Transantarctic Mountains, considered the natural border between West and East Antarctica.

During the summer of Antarctica, from late November to January, geologists Erik Gulbranson and John Isbell climbed the icy slopes of the mountains and there, among the rocks, they managed to find some fossil remains of an ancient forest.

At the end of the journey, geologists identified 13 fragments trees. The study found that the fossils belonged to plants that lived over 260 million years ago, shortly before the arrival of the dinosaurs.

Although the first fossils in Antarctica were discovered by Robert Falcon Scott in 1910, most of the frozen continent is still unexplored.

The Permian Period ended 251 million years ago in the largest mass extinction in history. More than 90% of the species on Earth disappeared, including the polar forests. Since the latter grew where there cannot be plants today, Gulbranson believes that trees were an extremely interesting species and is trying to understand why they became extinct.

According to the most accredited hypotheses, a massive increase in greenhouse gases, including carbon dioxide and methane, caused the extinction of the Permian-Triassic period. It is likely that over the course of 200.000 years - in a short time, in geological terms - volcanic eruptions in Siberia have released tons of greenhouse gases into the atmosphere.

"This forest is the discovery of life before extinction and can help us understand what caused the event", he said Gulbranson. He can also give clues as to what the plants looked like compared to today.

At the end of the Permian period, Antarctica was hot and humid and was part of Gondwana, the supercontinent that spanned the southern hemisphere and also included South America, Africa, India, Australia and the Arabian Peninsula.

Under the ice of Antarctica there is an ancient forest of 'resilient' trees

The vegetation consisted of mosses, ferns and an extinct plant called Glossopteris. It is probable that the forest extended across the entire Gondwana continent but did not have the biodiversity that characterizes the present ones. However the vegetation was able to survive and thrive in a variety of environments, given the large resilience.

This was not enough to save the trees from high concentrations of greenhouse gases. By studying the rings, Gulbranson and colleagues found that they rapidly transitioned from summer activity to winter "hibernation" within a month. Modern plants, on the other hand, take several months. Scientists do not yet know how the months of perpetual light affected the day-night cycles of plants.

“Today there is nothing like it. These trees can turn their growth cycles on and off like a switch, ”Gulbranson explained.

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