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TOPIC: The 'Great Dying'


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Global Extinction: Gradual Doom Is Just As Bad As Abrupt

A painstakingly detailed investigation shows that mass extinctions need not be sudden events. The deadliest mass extinction of all took a long time to kill 90 percent of Earth's marine life, and it killed in stages, according to a newly published report.
Thomas J. Algeo, professor of geology at the University of Cincinnati, worked with 13 co-authors to produce a high-resolution look at the geology of a Permian-Triassic boundary section on Ellesmere Island in the Canadian Arctic. Their analysis, published Feb. 3 in the Geological Society of America Bulletin, provides strong evidence that Earth's biggest mass extinction phased in over hundreds of thousands of years.

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The Permian extinction
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Scientists have singled out mercury as one of the major factors behind the earth's greatest extinction 250 million years ago, obliterating most marine and land species.
During the late Permian, the natural buffering system in the ocean became overloaded with mercury contributing to the loss of 95 percent of life in the sea.

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Permian Mass Extinction
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New evidence points to rapid collapse of Earth's species 252 million years ago.

The end-Permian extinction occurred 252.2 million years ago, decimating 90 percent of marine and terrestrial species, from snails and small crustaceans to early forms of lizards and amphibians. "The Great Dying," as it's now known, was the most severe mass extinction in Earth's history, and is probably the closest life has come to being completely extinguished. Possible causes include immense volcanic eruptions, rapid depletion of oxygen in the oceans, and - an unlikely option - an asteroid collision.
While the causes of this global catastrophe are unknown, an MIT-led team of researchers has now established that the end-Permian extinction was extremely rapid, triggering massive die-outs both in the oceans and on land in less than 20,000 years - the blink of an eye in geologic time. The researchers also found that this time period coincides with a massive buildup of atmospheric carbon dioxide, which likely triggered the simultaneous collapse of species in the oceans and on land.

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Catastrophe - Ep3: Planet of Fire 1

Catastrophe - Ep3: Planet of Fire 2

Catastrophe - Ep3: Planet of Fire 3

Catastrophe - Ep3: Planet of Fire 4

250 million years ago, 95% of life was wiped off the face of Earth in the biggest extinction event ever. But what was responsible? Back then, our planet was a very different place. Millions of years before the era of dinosaurs, creatures such as dicynodonts and gorgonopsians roamed the land, while the oceans too teemed with life. Then, in the blink of a geological eye, everything changed. Life itself was almost completely wiped out in what is known as the Permian extinction. 

Travelling to locations such as South Africa, California, and Iceland, the experts discover that the volcanic activity of the Siberian Traps led to the release of deadly gases from beneath the sea and rises in Earth's temperature. This turbocharged global warming brought drought and a breakdown in the food cycle, with even the strongest animals eventually succumbing to the conditions.



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Permian Mass Extinction
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Study details world's worst die-off: hell on Earth

 During the world's biggest mass extinction, Earth seemed pretty close to a description of hell - fiery, smoky and explosive - created by massive volcanic eruptions, according to research dug up in China.
In geologic terms, it was surprisingly quick, and it may provide a scary lesson about climate change for our future, authors of the new study say. It was the third of five extinctions in world history, occurring even before dinosaurs roamed.

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The Permian Mass Extinction





The Permian Desert



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The greatest mass extinction of all time? It wasn't as bad as first thought

The world's biodiversity was ravaged and studies had claimed it took land species as much as 15 to 30 million years to fully recover.
Yet when scientists examined sets of before and after fossils from north-eastern Arizona they found little difference in the genetic diversity.
The research, from the University of Rhode Island, now suggests life on Earth above water recovered in around five million years.

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Permian-Triassic extinction
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Acidic oceans linked to mass die-off

A Canadian-led team of scientists may have solved the biggest whodunit in Earth history in a study showing the all-time greatest mass extinction on the planet - which wiped out about 90 per cent of all species 250 million years ago - appears to have been linked to rising levels of ocean acidity.
Researchers have long believed massive volcanic eruptions in present-day Siberia - or possibly a huge meteorite strike - triggered the so-called Permian-Triassic extinction. But the precise mechanism of death for so many species remains a subject of debate, with some scientists convinced it was a resulting lack of oxygen in the Earth's oceans or a greenhouse-gas nightmare that nearly ended all plant and animal life.

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Fungi helped destroy forests during mass extinction 250 million years ago

The demise of the world's forests some 250 million years ago likely was accelerated by aggressive tree-killing fungi triggered by global climate change, according to a new study by a University of California, Berkeley, scientist and her Dutch and British colleagues.
The researchers do not rule out the possibility that today's changing climate could cause a similar increase in pathogenic soil bacteria that could devastate forests already stressed by a warming climate and pollution.
The study, available online today (Aug. 5), will be published in the September 2011 print edition of the journal Geology of the Geological Society of America.

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Permian extinction
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New research is helping astrobiologists understand the end-Permian extinction, a dramatic biological crisis that profoundly affected the history of life on Earth. However, the new data indicates that this major extinction event may not have been catastrophic for some organisms.

An international team of researchers studied the parareptiles, a diverse group of bizarre-looking terrestrial vertebrates which varied in shape and size. Some were small, slender, agile and lizard-like creatures, while others attained the size of rhinos; many had knobbly ornaments, fringes, and bony spikes on their skulls.
The researchers found that, surprisingly, parareptiles were not hit much harder by the end-Permian extinction than at any other point in their 90 million-year history. Furthermore, the group as a whole declined and diversified time and time again throughout its history, and it was not until about 50 million years after the end-Permian crisis that the parareptiles finally disappeared.

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Algae and bacteria hogged oxygen after ancient mass extinction, slowing recovery of marine life

A mass extinction is hard enough for Earth's biosphere to handle, but when you chase it with prolonged oxygen deprivation, the biota ends up with a hangover that can last millions of years.
Such was the situation with the greatest mass extinction in Earth's history 250 million years ago, when 90 percent of all marine animal species were wiped out, along with a huge proportion of plant, animal and insect species on land.
A massive amount of volcanism in Siberia is widely credited with driving the disaster, but even after the immense outpourings of lava and toxic gases tapered off, oxygen levels in the oceans, which had been depleted, remained low for about 5 million years, slowing life's recovery there to an unusual degree.

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