Tag Archives: permian-triassic extinction

252 million years ago, climate change nearly wiped out life on Earth; something similar is happening today

Great climatic changes triggered the Earth’s biggest extinction, which wiped off 70% of terrestrial life and 96% marine life 252 million years ago, a new study suggests. A similar process seems to be taking place today, researchers warn.

The barbary ape is one of the many creatures currently threatened by extinction as a result of human action.

Then…

We’re 252 million years in the past, in a period called the Permian. Almost all of the Earth’s landmass is clumped together into a supercontinent called Pangaea. Although it’s still in its earlier phases, life on Earth has developed to be remarkably diverse. But evolution was about to suffer a massive setback — a dramatic extinction that came to be known as “The Great Dying.”

“It was a huge event. In the last half a billion years of life on the planet, it was the worst extinction,” said Curtis Deutsch, an oceanography expert who co-authored the research with University of Washington colleague Justin Penn and Stanford University scientists Jonathan Payne and Erik Sperling.

Despite the magnitude of this event, researchers have found relatively few clues about it — until some 20 years ago.

The problem is that 252 million years is a long time (even in geological terms), and finding reliable evidence that survived the onset of this much time is not easy. However, modern dating techniques (particularly the U–Pb dating of zircon crystals) allowed geologists to pinpoint this extinction to a few thousands of years — which given the scale of things, is quite impressive.

Similarly, radiometric studies have revealed that the extinction coincided with (and was likely caused by) massive volcanic eruptions. However, not all was clear. Specifically, it was unclear how the volcanic eruption and the extinction event were related.

Now, a new study suggests that the determining mechanism was an all too familiar one: climate change.

Image credits: University of Washington.

Essentially, the eruptions caused intense and abrupt global warming, which in turn depleted the oxygen from the oceans, causing the ocean’s creatures to effectively suffocate. Using a complex model powered by a supercomputer, the authors found that the combination of these two factors alone (warming water and low oxygen) can “account for more than half the magnitude of the ‘Great Dying’”.

If those two factors seem somewhat familiar, it’s because they’re also taking place today.

… and now

The story seems remarkably similar to what we’re experiencing today, as researchers themselves underline in the study.

“Voluminous emissions of carbon dioxide to the atmosphere, rapid global warming, and a decline in biodiversity—the storyline is modern, but the setting is ancient,” Penn State geosciences professor Lee Kump, who was not part of the research team, wrote in a Science piece responding to the new findings.

Indeed, it’s stunning how similar the two situations are. In both cases, an event caused temperatures to rise in a relatively short amount of time — but whereas 252 million years ago that was a volcanic eruption, in this case, it’s the greenhouse gas emissions outputted by mankind.

“The ultimate, driving change that led to the mass extinction is the same driving change that humans are doing today, which is injecting greenhouse gases into the atmosphere,” Justin Penn, a University of Washington doctoral student in oceanography and the study’s lead author, told the Seattle Times.

“The study tells us what’s at the end of the road if we let climate [change] keep going,” warned Curtis Deutsch, Penn’s co-author and PhD adviser, as the latest projections show emissions hitting record-breaking levels this year. “The further we go, the more species we’re likely to lose… That’s frightening. The loss of species is irreversible.”

Scientists are also tracking oxygen depletion in the oceans, and have reported some worrying trends, which already start to resemble what was happening in the late Permian.

[panel style=”panel-danger” title=”Greenhouse gases” footer=””]The extinction event likely occurred over a timeframe of tens or hundreds of years, during which Earth’s temperatures increased by around 10°C (18°F). Oceans lost around 80% of their oxygen, and many parts of the seafloor became completely oxygen-free. This warming was almost certainly caused by a huge spike in greenhouse gas emissions, caused by volcanic activity.

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Simply put, we may be witnessing the start of another catastrophic period for Earth’s biodiversity, and contrary to popular belief, life doesn’t necessarily “bounce back” — it may be permanently affected. Previous studies have indicated that it took life at least 4-6 million years to recover after the Great Dying, while other authors put that figure towards 30 million years.

Credits: NASA.

Another striking similarity between the Great Dying and modern times is the devastation of insect populations. The ancient extinction is the only known mass extinction of insects — and insect populations have declined dramatically in the past few decades — the blink of an eye, in geological time.

If this all seems a bit alarming, well, it should. Finding so many similarities between the world’s greatest extinction event and today’s times is not something to be happy about. If our greenhouse gas emissions are not curbed, life on Earth (including humans) may be irreparably damaged.

“As our understanding of the drivers and consequences of end-Permian climate change and mass extinction improves,” Kump wrote, “the lessons for the future become clear.”

Within the Paris Agreement, countries pledged to reduce emissions and limit global warming to a maximum of 2 degrees Celsius over the pre-industrial levels, but globally, action has been lackluster, and several studies have found that an increase of over 4 degrees Celsius is much more likely.

World leaders are currently meeting in Katowice at the annual UN climate summit (in which the Paris Agreement was also signed) to decide the best course of action, but despite some remarkable initiatives, there are few reasons for optimism.

It’s easy to feel powerless in the face of such massive processes, but it’s important to remember that collectively, our decisions are one of the most powerful geological forces in our planet’s history. Your decisions do matter — make it count.

The study “Climate change and marine mass extinction” has been published in Science.

Artist's rendering of the landscape during end-Permian extinction. Credit: José-Luis Olivares/MIT.

Ozone-depleting chemicals may have caused the largest mass extinction in history

Artist's rendering of the landscape during end-Permian extinction. Credit: José-Luis Olivares/MIT.

Artist’s rendering of the landscape during end-Permian extinction. Credit: José-Luis Olivares/MIT.

Living organisms haven’t always had it easy and throughout their multi-billion-year-old history, they have frequently been threatened with annihilation. But there was no greater challenge than the Great Dying, a mass extinction event that occurred 250 million years ago. For almost a million years, a huge volcano in Siberia continuously erupted, wiping out 90% of all species. The scale of extinction was unprecedented but it was never clear what made this massive volcanic eruption so deadly — after all, it wasn’t the first nor the last event of its kind. Now, a new study explains what may have driven the Great Dying: reactive chemicals released from stockpiles beneath the crust that destroyed the ozone layer.

The Permian-Triassic extinction took place at the end of the Permian period, and in those times, living on our planet was hellish: global warming, ocean acidification and ocean anoxia (lack of oxygen) all worked together to wipe out most of life on Earth. According to a 2014 study performed by MIT researchers, the extinction event likely lasted for 60,000 years, with an uncertainty of 48,000 years. In geological terms, this is like the blink of an eye — too fast for most life on Earth to adapt. The samples also confirmed what was known for a while: the extinction was preceded by a sharp increase of carbon dioxide in the oceans.

The long-lasting volcanic eruptions from the Siberian Traps, a region of Russia whose steplike hills are a result of repeated eruptions of magma, released volatile chemicals, including carbon dioxide, into the atmosphere and oceans, covering an estimated five million cubic kilometers. Most of the carbon was absorbed by the oceans which act like huge heat-sinks, increasing sea temperatures by as much as 10 degrees Celsius – too hot for anything to survive. Around 96% of marine species and 70% of terrestrial species were obliterated by the Permian-Triassic extinction and it took life on Earth ten million years to recover from this event.

But the conditions life had to face in these dire times may have been even more challenging than previously hypothesized.

In a new study published in Nature Geoscience, Michael Broadley, a postdoctoral researcher at the Centre for Petrographic and Geochemical Research in Vandœuvre-lès-Nancy, France along with colleagues examined rocks from the lithosphere — the solid, outer part of the Earth sandwiched in between the crust and the mantle — which were captured by passing magma during the ancient eruption.

These samples provide a snapshot of the lithosphere’s composition prior to the event that brought them to the surface of the Earth. Before the eruption of the Siberian Flood Basalts, the researchers found that the lithosphere contained significant amounts of chlorine, bromine, and iodine. These elements, present in the halogen group on the periodic table, have since disappeared after the volcanic eruption.

The breakthrough was identifying these elements which were presented in extremely low concentrations — just a few parts per billion in the case of bromine and iodine.

“These rocks were a complete surprise. The level of halogens was much much higher than we were expecting. When we got these results we realised that we had something interesting. The level of enrichment is so high that we knew that even if only a small percentage was released to the atmosphere it could have potentially devastating effects for the Earth’s ozone layer,” Broadley told ZME Science.

Once these elements flooded the atmosphere, they reacted with the ozone layer, destroying it. The ozone layer cushions the planet’s surface from harmful UV radiation and exposure to higher levels of UV radiation (such as those associated with a thinned ozone layer) significantly raise the risks of developing cataract and skin cancer. Wide-scale exposure to UV levels expected in the absence of the ozone layer would drastically impact whole ecosystems.

Human activity recently made a huge, gaping hole in the ozone layer due to pollution with chlorofluorocarbons and hydrochlorofluorocarbons (CHCs and HCHCs), chemicals used in old refrigerators and spray cans. However, thanks to remarkable international collaboration, that hole is almost plugged now. Unfortunately, creatures living more than 250 million years were in no such luck.

Coupled with acid rain and gloomy sky, a thin ozone layer must have been quite a dramatic sight on the planet at the time.

“We knew from fossil evidence that there seems to be a high level of mutated spores and pollen around the time of the eruption of the halogens. These high level of mutation is considered to be related to higher levels of UV radiation at the time. We, therefore, consider that the huge amounts of halogens released from the lithosphere led to the destruction of the ozone layer and therefore led to high levels of solar UV radiation reaching the surface. Whilst potentially not immediately noticeable, the high levels of UV would have damaged DNA and led to plant sterility. Therefore if humans had been around at this time they may have witnessed the large scale deforestation and the collapse of the food chain,” Broadley said.

In the future, Broadley and colleagues are planning to study diamonds from the lithosphere. During their formation, the diamonds trap some lithospheric fluids, which may help answer how the Siberian lithosphere became so enriched with halogens in the first place. In the meantime, the study serves as a stark reminder of how fragile life can be.

“This study has parallels to modern times. During the 70s and 80s, scientists discovered the ozone hole, caused by the release of halogen-bearing compounds to the atmosphere. Thankfully global action was taken to reduce the emission of these compounds but our study shows the importance of the ozone layer and the potential consequences that can come about from its destruction,” Broadley said.

Ancient rocks reveal causes of Earth’s greatest mass extinction event

The Oman rocks that were used to reveal the causes of the Permian-Triassic Boundary extinction event. Credit: Matthew Clarkson
The Oman rocks that were used to reveal the causes of the Permian-Triassic Boundary extinction event.
Credit: Matthew Clarkson

Around 252 million years ago, the Earth experienced the biggest mass extinction event in its history. Referred to as both the Permian-Triassic extinction event and the Great Dying, it wiped out over 90 percent of marine life and approximately two-thirds of land-dwelling animals. Now, a new study sheds light on the causes of this event and reveals why the Earth’s marine creatures took so long to recover from it.

Although previous research pointed to a lack of dissolved oxygen and increase in sulphides in the Earth’s waters as the main cause of the mass extinction and the planet’s delayed recovery, the new study suggests that these anoxic conditions were complex and the high sulphide levels were not ubiquitous.

Using chemical techniques to analyze data from six sampling sites in Oman – spanning a range of shallow regions all the way to the deeper ocean – the team revealed that despite the lack of oxygen in the water, no toxic sulphides were present. Instead, the team noticed an increase in iron levels.

Contrary to previous beliefs, the new findings suggest that low oxygen in combination with high levels of iron – not sulphides – were the main causes of the delayed recovery of marine life that occurred following the Great Dying. Furthermore, the data suggests that some shallow waters did not suffer from the low oxygen levels present in other bodies of water, which likely helped increase the diversity of life in these areas.

“The neat point about this study is that it shows just how critical an absence of oxygen, rather than the presence of toxic sulphide, was to the survival of animal life,” said Simon Poulton of the University of Leeds and co-author of the study. “We found that marine organisms were able to rapidly recolonize areas where oxygen became available.”

Researchers believe that the anoxic conditions behind the Permian-Triassic extinction event likely stemmed from a combination of run-off from land rock erosion and high temperatures, although the exact causes of the extended recovery period are still not known.

“We knew that lack of oxygen in the oceans played a key role in the extinction and recovery processes, but we are still discovering how exactly it was involved,” said Matthew Clarkson of the University of Edinburgh’s School of GeoSciences and lead author of the study. “Our findings about the chemistry of the ocean at the time provide us with a clearer picture of how this complex process delayed the recovery of life for so long.”

Journal Reference: Dynamic anoxic ferruginous conditions during the end-Permian mass extinction and recovery. 19 July 2016. 10.1038/ncomms12236

The Permian extinction – caused by “lemon juice” acidic rain ?

  • The Permian extinction was the biggest extinction ever, killing 96% of all marine species and 70% of terrestrial vertebrates
  • Possible causes include: impact, loss of oxygen and volcanic eruptions
  • Researchers tested the validity of the last hypothesis, finding it likely

The biggest extinction – ever

Artistic representation of the Permian plants, affected by acidic rain. Via MIT.

Artistic representation of the Permian plants, affected by acidic rain. Via MIT.

MIT Researchers believe that rain as acidic as undiluted lemon juice may have contributed to massive extinction that took place at the end of the Permian, 252 million years ago. These acidic rains may have played a part in killing off plants and organisms around the world during what is regarded as the most severe extinction the world has ever gone through.

It was so severe that it killed 96% of all marine species and 70% of terrestrial vertebrate species – and it took life about 10 million years to recover from it!

Pin-pointing the exact cause (or causes) of the Permian–Triassic extinction event is a difficult undertaking because it took place so long ago that most of the evidence was destroyed, eroded or buried away. There’s a major scientific debate, centering on several potential causes:

– an asteroid impact, similar to what wiped off the dinosaurs at the end of the Mesozoic
– a gradual, global loss of oxygen in the oceans
– a host of environmental changes caused by massive volcanic eruptions in today’s Siberia.

Now, researchers at MIT have simulated the final possibility. They created a climate model for a Permian world in which massive eruptions took place, ejecting volcanic gases (including sulfur) into the atmosphere. They found that if this were the case, then sulfur emissions were significant enough to create widespread acid rain throughout the Northern Hemisphere, with pH levels reaching 2 — as acidic as undiluted lemon juice. These acidic rains alone would have been enough to maim virtually all living plants, halting their growth and development, ultimately leading to the massive extinction.

“Imagine you’re a plant that’s growing happily in the latest Permian,” says Benjamin Black, a postdoc in MIT’s Department of Earth, Atmospheric and Planetary Sciences. “It’s been getting hotter and hotter, but perhaps your species has had time to adjust to that. But then quite suddenly, over the course of a few months, the rain begins to sizzle with sulfuric acid. It would be quite a shock if you were that plant.”

Volcanoes in Siberia

The world at the time of the Permian extinction. Highlighted are the biggest igneous provinces - notice Siberia.

The world at the time of the Permian extinction. Highlighted are the biggest igneous provinces – notice Siberia. Source

It’s hard to wrap your mind around such a dramatic event as this one, and in a way, it’s hard to believe that it was just a single cause – it seems pretty likely that at least a couple of separate, unfortunate elements converged towards this extinction. Geologists analyzing the rocks in Siberia found evidence of immense volcanism that came in short bursts beginning near the end of the Permian period and continuing for another million years. The volume of the magma was several million cubic kilometers, enough to put a thick cover over all the United States. But even so, were these eruptions enough on their own?

The group simulated 27 scenarios, each approximating the release of gases from a plausible volcanic episode, including a wide range of gases in their simulations, based on estimates from chemical analyses and thermal modeling. They then modeled the interaction between these gases and the atmosphere, ultimately, how they were absorbed and then came down as low pH rain.

They found that with repeated bursts of volcanic activity, the acidic rains had a dramatic effect on land plants, probably going way past the point they could handle.

“Plants and animals wouldn’t have much time to adapt to these changes in the pH of rain,” Black says. “I think it certainly contributed to the environmental stress which was making it difficult for plants and animals to survive. At a certain point you have to ask, ‘How much can a plant take?’”

Now, Black hopes paleontologists and geochemists will consider his own results and compare them with their own observations of the Permian extinction, in order to paint a more accurate picture.

“It’s not just one thing that was unpleasant,” Black says. “It’s this whole host of really nasty atmospheric and environmental effects. These results really made me feel sorry for end-Permian organisms.”

Ancient volcanic eruptions caused mass extinction 200 million years ago

Some 200 million years ago  half of all life on Earth went extinct, thus providing a window of opportunity for the dinosaurs to evolve in now unoccupied niches and dominate the planet for the next 135 million years. Curiously enough, after the dinosaurs were at their own term wiped out by a calamity – presumably at the hand of an asteroid impact – our own genus, the mammals, rose up and filled the gaps. Recognize a pattern here?

dinosaurs

Anyway, let’s head back to a time when dinosaurs were yet to become the dominant species on Earth, in the End-Triassic, some 200 million years ago. During this time a massive extinction known as the End-Triassic Extinction (ETE) brought doom upon more than half of all life in the world. A new study from a team of geologists links the abrupt disappearance of approximately half of Earth’s species to a series of massive volcanic cataclysms that took place roughly at the same time.

“This may not quench all the questions about the exact mechanism of the extinction itself.” said the study’s coauthor Paul Olson, a geologist at Columbia University’s Lamont-Doherty Earth Observatory. “However, the coincidence in time with the volcanism is pretty much ironclad.”

Did the extinction come after the volcanic cataclysm or did the volcanic cataclysm come after extinction? Common sense dictates that you’d need a global cataclysm to occur first in order to cause such a widespread extinction, but science isn’t about what seems reasonable, but about what you can prove. For years scientists  have suggested that the ETE and at least four other known past extinctions were caused in part by mega-volcanism and the resulting climate change, however previous studies have been unable to prove this.

The team of international researchers analyzed rock samples in Nova Scotia, Morocco, and even the suburbs of New York City and  used the decay of uranium isotopes to pull exact dates from basalt, a rock known to been left by eruptions. Around the time of the ETE, the supercontinent known as Pangaea began to break apart, and as such a series of massive eruptions around the world that lasted for 600,000 years created a rift that ultimately became the Atlantic Ocean.

Previous studies were obstructed from making a sound correlation between the Triassic mass extinction and the volcanic events from around the same time since errors in calculating the eruptions’ timing ranged between one to three million year. After analyzing a key mineral called zircon — found in igneous rocks such as basalt — scientists were able to narrow down their margin of error to 20,000 to 30,000 years, or slightly before the mass extinction event.

“Zircon is a perfect time capsule for dating those rocks,” said Blackburn. “When the mineral crystallizes, it incorporates uranium, which decays over a known time with respect to the element lead. By measuring the ratio of uranium to lead in our samples, we can determine the age of those crystals.”

Findings were published in the journal Science.

Triassic fossil of an eel-like conodont. (c) Yadong Sun.

During the greatest mass extinction in Earth’s history the world’s oceans reached 40°C – lethally hot

Between 247 to 252 million years ago, Earth life was going through quite possibly its most dire time. During this period some 90% of world’s species were wiped out, but what puzzled scientists for so long is the fact that it took five million years for life to recover after this apocalypse. A new study conducted by an international team of scientists found why it took so long – it was literally too hot to survive.

During what’s now commonly known as the end-Permian mass extinction, the Earth was a massive barren landscape. The die-off not only wiped out most marine and terrestrial animals, but plants too, which ensued a vicious circle. Plants absorb carbon dioxide, preventing the atmosphere from getting warmer, but as these died off in term as well, temperatures rose even higher too lethal levels. Other mass extinction periods took a few hundred thousand years for life to recover to previously similar levels, however this pre-Triassic extinction trialed life on Earth like never before – it needed five million years to surface.

pre-permian mass extinction

Earth at this time was a very peculiar world. The tropics would have a wet climate, much like today, but with no forests, only shrubs and ferns. Shellfish were the only marine creatures in the oceans. Virtually no land animals existed because their metabolisms would not have withstood such high temperatures. Only the polar regions offered a habitable refuge from the baking heat.

Too darned hot to survive!

Triassic fossil of an eel-like conodont. (c) Yadong Sun.

Triassic fossil of an eel-like conodont. (c) Yadong Sun.

Scientists from the University of Leeds, the China University of Geosciences and the University of Erlangen-Nurnburg (Germany) analyzed fossil records of some of the few life-forms that had survived the Permian extinction – sturdier species like snails and clams. After studying the oxygen isotopes in 15,000 conodont fossils extracted from rocks in South China, which serve as ancient seawater temperature records, the researchers found that oxygen isotopes water temperatures close to the ocean’s surface could reach 40°C.

“Global warming has long been linked to the end-Permian mass extinction, but this study is the first to show extreme temperatures kept life from restarting in equatorial latitudes for millions of years,” said Yadong Sun, lead author of a new study that documents the team’s findings.

Could it happen again?

Until now, climate modelers have assumed sea-surface temperatures cannot surpass 30°C. The modern average for the same area is between 77 and 86 degrees Fahrenheit (25 and 30 degrees Celsius).

Since 1880, global temperatures have increased by 1.4 degrees Fahrenheit (0.8 degree Celsius), two thirds of which have occurred after 1975. Despite this alarming trend, scientists assure that we’re far from witnessing a similar dire time falling upon us. Still, the pre-Permian extinction serves as a reminder of just how tough life on Earth had it, and how close it was to obliteration.

“Nobody has ever dared say that past climates attained these levels of heat. Hopefully future global warming won’t get anywhere near temperatures of 250 million years ago, but if it does we have shown that it may take millions of years to recover,” noted co-researcher Paul Wignall, from the University of Leeds.

Findings were presented in the journal Science.

Earth took 10 million years to recover from biggest extinction

Some 250 million years ago, life on Earth passed through its toughest time so far, as 96% of all marine species and over three quarters of land vertebrates went extinct. According to British researchers, the mass extinction was so severe that it took life 10 million years to recover.

With less than 10 percent of plants and animals surviving and a huge number of biological niches left unfilled, a quick bounce back could seem likely, but according to Dr Zhong-Qiang Chen, from the China University of Geosciences in Wuhan, and Professor Michael Benton from the University of Bristol, that’s not really the case; two reasons stood in the way of life: the sheer intensity of the crisis, and continuing grim conditions on Earth after the first wave of extinction.

The Permian-Triassic extinction took place at the end of the Permian period, and in those times, living on our planet was hellish: global warming, ocean acidification and ocean anoxia (lack of oxygen) all worked together to wipe out the biggest part of life on Earth.

“It is hard to imagine how so much of life could have been killed, but there is no doubt from some of the fantastic rock sections in China and elsewhere round the world that this was the biggest crisis ever faced by life,” Dr Chen said.

Current research of the conditions showed that things didn’t become pink after that – six million years after the main event conditions didn’t change significantly with repeated carbon and oxygen crises, warming and other ill effects. Some groups of animals on the sea and land did recover quickly and began to rebuild their ecosystems, but they suffered further setbacks.

“Life seemed to be getting back to normal when another crisis hit and set it back again,” Professor Benton, Professor of Vertebrate Palaeontology at the University of Bristol, said. “The carbon crises were repeated many times, and then finally conditions became normal again after five million years or so.”

However, after the environmental crisis ceased, more complex ecosystems emerged, including ancestral crabs and lobsters, as well as the first marine reptiles, paving the way for modern marine ecosystems.

“We often see mass extinctions as entirely negative but in this most devastating case, life did recover, after many millions of years, and new groups emerged. The event had re-set evolution. However, the causes of the killing – global warming, acid rain, ocean acidification – sound eerily familiar to us today. Perhaps we can learn something from these ancient events,” Professor Benton added.