Geologists uncover Antarctica's fossil forests

November 9, 2017 by Matthew Wamser, University of Wisconsin - Milwaukee
Erik Gulbranson, paleoecologist and visiting assistant professor at UWM, studies some of the fossilized trees he brought back from Antarctica. Gulbranson is returning there for further research this year. Credit: UWM Photo/Troye Fox

During Antarctica's summer, from late November through January, UW-Milwaukee geologists Erik Gulbranson and John Isbell climbed the McIntyre Promontory's frozen slopes in the Transantarctic Mountains. High above the ice fields, they combed the mountain's gray rocks for fossils from the continent's green, forested past.

By the trip's end, the geologists had found fossil fragments of 13 trees. The discovered fossils reveal that the trees are over 260 million years old, meaning that this grew at the end of the Permian Period, before the first dinosaurs, when Antarctica was still at the South Pole.

"People have known about the fossils in Antarctica since the 1910-12 Robert Falcon Scott expedition," said Gulbranson, a paleoecologist and visiting assistant professor in UWM's Department of Geosciences. "However, most of Antarctica is still unexplored. Sometimes, you might be the first person to ever climb a particular mountain."

The time frame is exactly what they are looking for. The Permian Period ended 251 million years ago in history's greatest , as the Earth rapidly shifted from icehouse to greenhouse conditions. More than 90 percent of species on Earth disappeared, including the polar forests. Gulbranson believes that the trees in the Antarctic forests were an extremely hearty species and is trying to determine why they went extinct.

Many scientists now believe that a massive increase in atmospheric greenhouse gases, such as and methane, caused the Permian-Triassic extinction. It's likely that over the course of 200,000 years – a short time, geologically speaking – volcanic eruptions in Siberia released many tons of greenhouse gases into the atmosphere.

Isbell, a distinguished professor of geosciences at UWM, has previously studied Antarctica's Permian glacial deposits to determine how the climate changed. On this expedition, he used the rocks around the fossilized trees to determine how the fossils fit into Antarctica's geologic history.

"This forest is a glimpse of life before the extinction, which can help us understand what caused the event," Gulbranson said. It can also give clues to how plants were different than today.

At the Permian Period's end, Antarctica was warmer and more humid than it is today. The world's continents, as we know them, were packed together in two giant landmasses – one in the north and one in the south. Antarctica was part of Gondwana, the supercontinent spanning the Southern Hemisphere that also included present-day South America, Africa, India, Australia and the Arabian Peninsula.

There would have been a mixture of mosses, ferns and an extinct plant called Glossopteris, and it's likely that this forest stretched across the entirety of Gondwana.

Gulbranson said that the fossil forests looked different than forests today. During the Permian Period, forests were a potentially low diversity assemblage of different plant types with specific functions that affected how the entire forest responded to environmental change. This is contrast to modern high-latitude forests that display greater plant diversity.

"This plant group must have been capable of surviving and thriving in a variety of environments," Gulbranson said. "It's extremely rare, even today, for a group to appear across nearly an entire hemisphere of the globe."

But not even these robust forests survived the high carbon dioxide concentrations of the mass extinction.

The resilient plants also must have survived through the polar extremes of perpetual light and total darkness. Even in a warmer past, the polar regions would have experienced months of darkness in winter and would have gone without sunset during the summer months.

By studying the preserved tree rings, Gulbranson and colleagues have found that these trees transitioned from summer activity to winter dormancy rapidly, perhaps within a month. Modern plants make the same transition over the course of several months and also conserve water by making food during the day and resting at night. Scientists don't yet know how months of perpetual light would have affected the plants' day-and-night cycles.

"There isn't anything like that today," Gulbranson said. "These trees could turn their growing cycles on and off like a light switch. We know the winter shutoff happened right away, but we don't know how active they were during the summertime and if they could force themselves into dormancy while it was still light out."

He'll return to the site later this month and stay through January 2018. He hopes to learn more about the extinction event. He previously wasn't able to study the extinction period because of weather constraints and aircraft troubles.

Gulbranson is going to look for deposits from the mass extinction to see if he can determine exactly how the forests responded as carbon dioxide rose.

"The geologic record shows us the beginning, middle and end of climate change events," Gulbranson said. "With further study, we can better understand how and climate change affect life on Earth."

Explore further: Video: Research team discovers plant fossils previously unknown to Antarctica

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14 comments

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cantdrive85
1 / 5 (8) Nov 09, 2017
This article is a perfect example of how religious beliefs are 'not linked to intuition or rational thinking'
https://phys.org/...nal.html
Nik_2213
5 / 5 (9) Nov 09, 2017
#c, what have ancient Antarctic forests to do with religious beliefs ?? Please show working...
leetennant
5 / 5 (10) Nov 09, 2017
This article is a perfect example of how religious beliefs are 'not linked to intuition or rational thinking'
https://phys.org/...nal.html


#c, what have ancient Antarctic forests to do with religious beliefs ?? Please show working...


No clue but I imagine we're in for some deranged half-baked climate change denial...
cantdrive85
1 / 5 (8) Nov 09, 2017
#c, what have ancient Antarctic forests to do with religious beliefs ?? Please show working...

Ancient Antarctic forests have nothing to do with religious beliefs, the acolytic adherence to failed theories and irrational ad hoc explanations to fit the observations to beliefs that clearly do not support the data is the religiocity on display.
Nik_2213
5 / 5 (8) Nov 09, 2017
#c, which beliefs ? Which data ? Please don't just rant !!
yep
1 / 5 (4) Nov 09, 2017
Probably the idea that carbo dioxide would be the cause for the death of trees, unless to much would create an acid rain like it may be creating ocean acidification, you think they would just grow better?

Always thought global warming was a distraction to the chemicals in our foods, house hold products, pharmaceuticals, plastics etc that end up in mothers milk to the tap water slowly poisoning us and the enviornment, like we are frogs in a pot of water slowly heating up to boil unaware of the larger picture while the profits keep rolling in for the status quo.
leetennant
5 / 5 (4) Nov 10, 2017
Probably the idea that carbo dioxide would be the cause for the death of trees, unless to much would create an acid rain like it may be creating ocean acidification, you think they would just grow better?

Always thought global warming was a distraction to the chemicals in our foods, house hold products, pharmaceuticals, plastics etc that end up in mothers milk to the tap water slowly poisoning us and the enviornment, like we are frogs in a pot of water slowly heating up to boil unaware of the larger picture while the profits keep rolling in for the status quo.


Ergh. Yeah, the call for more environmental protections is just a "distraction" from... a need for greater environmental protections. I blame the lead that neocons keeps pumping into our water.
Shootist
1 / 5 (4) Nov 10, 2017
This article is a perfect example of how religious beliefs are 'not linked to intuition or rational thinking'
https://phys.org/...nal.html


#c, what have ancient Antarctic forests to do with religious beliefs ?? Please show working...


No clue but I imagine we're in for some deranged half-baked climate change denial...


"The polar bears will be fine". -- Freeman Dyson

When barley, wheat, and cattle, have been successfully cultivated in Greenland for ~350 - ~400 years give me a call, it's still TOO COLD (though the Greenlanders are well chuffed over their cabbage agriculture developed during the past 20-30 years).
yep
1 / 5 (3) Nov 10, 2017

Ergh. Yeah, the call for more environmental protections is just a "distraction" from... a need for greater environmental protections. I blame the lead that neocons keeps pumping into our water.

According to the ice core data we were on a warming trend almost like clockwork over the last 800,000 years. The industrial era hit with fossil fuel and deforestation. In the 1930's the only competition biomass alternative to petroleum was eliminated. In 1940's three major corporations buy up public transit and train routes in 48 cities across the country and demolish them and we became a car culture. 1970's Nixon instead of bringing on slow breeder reactors supports the petrochemical military complex with depleted uranium rounds staying with fast breeders. At the same time independent farmers are producing hydrogen from solar and running their farm equipment. Our economy is bought and paid for.
Yes, I thought global warming was a distraction, and in some ways I still think it is.
yep
5 / 5 (3) Nov 10, 2017
Ocean acidification scares me. I have biked to work for decades, I avoid many products, from produce brought from the other side of the world to products containing tox.
As an individual there is only so much I can do.
The fact is a failure of leadership because our politicians are corporate shills, but the only thing that will change the situation are the corporations deciding to do better to be better.
barakn
5 / 5 (2) Nov 10, 2017
No evidence for wheat growing in Greenland at all. Zip, zilch, nada. The evidence for barley consists of a few scorched grains in a single layer at the bottom of one trash heap. "The find also substantiates a well-known text from about 1250, 'King's mirror (Konungs skuggsjá)', which mentions in passing that the Vikings attempted to grow grain on Greenland. It is the only report about cultivating barley that we have from that time and says: "As to whether any sort of grain can grow there, my belief is that the country draws but little profit from that source. And yet there are men among those who are counted the wealthiest and most prominent who have tried to sow grain as an experiment; but the great majority in that country do not know what bread is, having never seen it."" https://ancientfo...eenland/
yep
4 / 5 (2) Nov 10, 2017
No evidence for wheat growing... great majority in that country do not know what bread is, having never seen it."" https://ancientfo...eenland/

So you miss read shootists point.
Mine was apparently over Lee and your heads. I'll be more specific.
At the end of the nineties approximately 120 corporations ran the world probably less now with consolidation. We have the economy they want. We could easily have a different reality within a few years, but who wants to let go of the golden goose. We got ours f*ck clean water and air we sell filters for that shit.
leetennant
5 / 5 (2) Nov 10, 2017
No evidence for wheat growing... great majority in that country do not know what bread is, having never seen it."" https://ancientfo...eenland/

So you miss read shootists point.
Mine was apparently over Lee and your heads. I'll be more specific.
At the end of the nineties approximately 120 corporations ran the world probably less now with consolidation. We have the economy they want. We could easily have a different reality within a few years, but who wants to let go of the golden goose. We got ours f*ck clean water and air we sell filters for that shit.


No, it's you who's making no sense. Those are the people who caused climate change and are trying to STOP us doing something about it. So how the hell can climate change be a distraction from that? It makes no damn sense.
yep
3 / 5 (1) Nov 11, 2017
No, it's you who's making no sense. Those are the people who caused climate change and are trying to STOP us doing something about it. So how the hell can climate change be a distraction from that? It makes no damn sense.


Because it is a tool used to divide us and media is the wedge. Break it down to what there is no aurgument about.
http://news.mit.e...-us-0829
There is no denial of mortality and disease statistics. There is no denial of quality of life issues.
We are the ones driving these cars and using power from these coal plants. We are giving our children asthma and fracking our ground water. We are those people.

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