Tree fossils reveal Antarctica had forest before time of the dinosaurs
The now frozen Antarctica had a forest during the Permian Period, before the time of the dinosaurs. How do ancient polar forest differ with the modern day forests we see today?
Fossil fragments of ancient trees in Antarctica suggest that the now frozen continent was not as barren as it is today. Evidence that researchers gathered after climbing the slopes of the McIntyre Promontory in the Transantarctic Mountains showed Antarctica had a thriving forest before the dinosaurs walked on Earth.
After looking for evidence of the cold continent’s potentially lush past, University of Wisconsin - Milwaukee (UWM) researchers found fossil fragments belonging to 13 trees that are more than 260 million years old.
A frozen wilderness
“We take it for granted that Antarctica has always been a frozen wilderness, but the ice caps only appeared relatively recently in geological history,” Jane Francis, from the University of Leeds, has said.
The age of the fossils revealed of forest in Antarctica at the end of the Permian Period, the time before the first dinosaurs emerged.
About 251 million years ago, the Permian Period ended in a mass extinction event as the Earth’s climate conditions rapidly shifted. Over 90 percent of the Earth’s species were wiped out, and these included the polar forests.
The volcanic eruptions in Siberia over a period of 200, 000 years may have released massive amounts of greenhouse gases. Scientists now think that the increase in the amount of atmospheric greenhouse gases, such as the Earth -warming methane and carbon dioxide, is behind the Permian-Triassic extinction.
At the end of the Permian Period, Antarctica was more humid and even warmer when compared to what it is today. It was also part of the Gondwana supercontinent that spanned the Southern Hemisphere and also included what is now the Arabian Peninsula, Australia, India, Africa and South America.
Researchers said that the forest, which likely spanned across the whole of the Gondwana continent, likely had a mixture of ferns, mosses and a now extinct plant known as Glossopteris.
Researchers revealed that the fossil forests were different compared with present day forests. Forests during the Permian period potentially had a low diversity of plants with particular functions that contributed to the way the forests responded to changes in the environment.
These ancients forests were in contrast to the characteristics of modern day high-latitude forests that are marked by greater plant diversity.
Unfortunately, the robust forests did not survive the high concentration of greenhouse gas during the mass extinction.
The researchers plan to return to the site to look for mass extinction event deposits that can shed more light on how the forests responded to the rising level of carbon dioxide in the atmosphere.
“With further study, we can better understand how greenhouse gases and climate change affect life on Earth,” Gulbranson said.
These ancients forests were in contrast to the characteristics of modern day highlatitude forests that are marked by greater plant diversity.