Tag Archives: permian extinction

Acid Rain played a part in Earth’s biggest extinction

The Permian was a geologic period that ended some 250 million years ago, with the largest extinction our planet has known. Geologists have now found evidence that global acidic rain accentuated or was even the main cause for the massive extinction.

Acidic rain may have caused the Permian Extinction. Image via MIT.

The Permian is a geological period from the Paleozoic Era, lasting from 298.9 to 252.2 million years ago. It is the period in which mammals and turtles started emerging, and its end is marked by the largest extinction in the Earth’s history. The extinction wiped out 96% of all marine species and 70% of terrestrial vertebrate species. It is also the only mass extinction of insects. Because so much biodiversity was lost, it took life up to 10 million years to bounce back.

Pinpointing the exact cause or causes of the Permian–Triassic extinction event is difficult because it took place 250 million years ago, and most of the evidence was erased or buried under many layers of earth. Therefore, we don’t really know what happened, but the main theories are asteroid impact and volcanic eruption – we know that the final stages of the Permian had two flood basalt events. Now, this new study has found evidence of massive rain during the Permian extinction, which seems to support the idea of a massive volcanic eruption – but it could also indicate that acidic rains themselves have caused the extinction.

“Our data fits the idea that acid rain caused the microbes to cease functioning,” said Henk Visscher, a paleoecologist at Utrecht University in the Netherlands and a member of the study.

Geologists analyzed rock samples from the Dolomite Mountains in Italy and found evidence of an organic compound called vanillin. Vanillin is most prominent as the principal flavor and aroma compound in vanilla, but it is also an indicator of acidic rain. Their evidence suggests that the soils on land were very acidic – so acidic that they had the potential to destroy entire ecosystesms.

Mark Sephton and study co-author Cindy Looy investigate the Permian-Triassic boundary in Italy’s Butterloch Canyon. (Courtesy of Mark Sephton)

Professor Mark Sephton, co-author of the paper from the Department of Earth Science and Engineering at Imperial College London, said:

“The end of the Permian was a major catastrophe for Earth, which saw nearly all plant and marine life obliterated. Acid rain destroyed the delicate ecosystem on land, making the soils as acidic as lemon juice or vinegar, which killed off nearly everything.”

The rain was so acidic, it was basically vinegar.

“For the first time, we can say that soils from this time had an acidity similar to that of vinegar,” says Mark Sephton, a geologist at Imperial College London whose team will publish the finding in February in the journal Geology.

However, before researchers can say with certainty that this process took place all over the world, they have to analyze samples from other areas in the world. Accessing 250 million year old rocks is no easy feat, but it’s necessary to confirm that this was not only a local situation.

Journal Reference: Terrestrial acidification during the end-Permian biosphere crisis?

 

Artist impression of how the landscape must have looked like during the end-Permian extinction. Photo: JOSÉ-LUIS OLIVARES/MIT

The most devastating mass extinction in Earth’s history happened much faster

Some 252 million years ago,  96 percent of marine species and 70 percent of life on land became extinct following a yet unconfirmed series of cataclysmic events. Around this time, billions and billions of organisms were killed and life on Earth faced its most dire moments. This is known as the end-Permian extinction, and many theories have been devised trying to explain what triggered this massive die-off. A new geological analysis by scientists at MIT provides a refined time frame during which the extinction took place. Apparently, the extinction happened much faster than previously believed. Moreover, armed with this information, scientists may now test some of the leading hypotheses that try to explain the extinction.

Artist impression of how the landscape must have looked like during the end-Permian extinction. Photo: JOSÉ-LUIS OLIVARES/MIT

Artist impression of how the landscape must have looked like during the end-Permian extinction. Photo: JOSÉ-LUIS OLIVARES/MIT

Sam Bowring, the Robert R. Shrock Professor of Earth and Planetary Sciences at MIT, and team first traveled to Meishan, China in 2006. Here, geologists from all over the world have made various trips since the area holds invaluable clues  in its layers of sedimentary rock. On section of rock, in particular, is thought to delineate the end of the Permian, and the beginning of the Triassic, based on evidence such as the number of fossils found in surrounding rock layers.

A massive die-off

Their first sample analysis suggested that the  end-Permian likely lasted less than 200,000 years, as reported in 2011. Using a more refined technique, Bowring now says that they’ve reached a more accurate time-frame.  Rock samples collected from five volcanic ash beds at the Permian-Triassic boundary were pulverized, so that  tiny zircon crystals containing a mix of uranium and lead could be gathered. The researchers then separated the the lead from the uranium  and measured the ratios of both isotopes to determine the age of each rock sample.

The new measurements reveal a more precise age model for the end-Permian extinction. It likely lasted for  60,000 years — with an uncertainty of 48,000 years . In geological terms, this is nothing more than the blink of an eye. Apparently, this was 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 in carbon dioxide in the oceans.

What’s the killer?

Some  10,000 years before the die-off, a massive and sudden influx of carbon dioxide was released into the atmosphere, poisoning life on land and acidifying the world’s oceans. 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. It took life on Earth ten million years to recover from this event. It’s important to note that ocean acidification is happening today at a growing rate due to global warming and man-made carbon emissions.

[ANOTHER THEORY] Permian extinction caused by ‘lemon juice’ acid rain [?]

What triggered this dramatic cataclysm? The leading theory is that it was caused by long-lasting volcanic eruptions from the Siberian Traps, a region of Russia whose steplike hills are a result of repeated eruptions of magma. The eruption  released volatile chemicals, including carbon dioxide, into the atmosphere and oceans, covering an estimated five million cubic kilometers.

The new refined timeline adds weight to this theory, but it’s still too early to tell for sure. Next, Bowring plan to determine an equally precise timeline for the Siberian Traps eruptions. If the eruptions and the eruption timeline overlap, than scientists can infer with a degree of confidence that indeed that’s what caused the extinction.

“We’ve refined our approach, and now we have higher accuracy and precision,” Bowring says. “You can think of it as slowly spiraling in toward the truth.”

The report was published in the Proceedings of the National Academy of Science. 

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.”

Bus sized Triassic marine monster sheds light on ecosystems

A new species of “sea monster” was unearther in Nevada – a predator so fierce that it often hunted prey as big or bigger than itself.

ichthyosaurus-sea-monster-secrets-revealed_62934_600x450

Thalattoarchon saurophagis translates into “lizard-eating sovereign of the sea” – and boy is that a good name. It measured well over 8 meters and lived some 244 million years ago, during the Triassic, before the Jurassic period. The creature was an early ichtyosaur, giant marine reptiles that resembled dolphins but were the dominant marine predators for tens of millions of years.

Paleontologists from the Berlin’s Museum of Natural History said the fossil is unusually well preserved, maintaining its skull, fins, and entire vertebral column.

“It is pretty amazing, particularly for an animal this size,” said Fröbisch, who is also a National Geographic explorer.

ichtyosaur fossil

Ichtyosaur fossil

If Thalattoarchon would have any equivalents today, those would be sharks and killer whales (oracas). But what’s truly interesting about the fossil is that it shows how species and even ecosystems could bounce back from the most catastrophic event.

Nature’s struggles

“This animal occurs only eight million years after the biggest mass extinction event in Earth’s history, the Permian extinction, which literally wiped out up to 95 percent of all the species in the ocean,” Fröbisch explained. “The ocean was a pretty empty place afterward.”

permian_extinct5_hThe Permian extinction was indeed the most tragic event in our planet’s history; it occured 252.28 million years ago and its exact cause (or causes) are still unknown. It was a key moment for all life on Earth, much more difficult than the event that wiped out the dinosaurs 65 million years ago. But fossil records showed that life quickly bounced back after this event, despite all odds.

Where does Thalattoarchon fit in ? Well, when ecosystems bounce back, they bounce from the bottom up. If a top predator like itself appears, that means there’s a whole lot of food for it available, which means that the ecosystem has pretty much recovered; to put it another way, top predators are the last ones to reemerge.

“So with the appearance of Thalattoarchon we know it was complete and that it had the same structure as modern ecosystems, the same structure we’ve seen in place, with different players, ever since.”

Despite thriving for over 160 million years as the top predator, Thalattoarchon and his fellow ichtyosaurs vanished without a trail, without leaving any indication as to what led to their demise, and without leaving any descendants.

“Toward the end of the Cretaceous, they declined more and more, and their diversity also declined—and then they finally disappeared,” Fröbisch said.

It’s actually possible that at one point, they became too good for their own sake – virtually eliminating all the food sources available.

Via National Geographic

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.