Sunday , January 24 2021

Finally, we know what killed Marine life in the most deadly mass extinction in history



About 252 million years ago, the Earth underwent catastrophic destruction – an existential event so severe that it wiped out nearly all life on Earth.

Up to 70 percent of all terrestrial vertebrates have been killed, and the vast 96 percent of all marine species, including the famous trilobite that previously survived two other massive existential events.

This is called the Peruvian-Triassic Existential Event, also known as the Great Death, and as far as we know it is the poorest event in Earth's history.

It is widely accepted that climate change is the culprit – in particular, that the long-term volcanic activity in Siberia has burned so many materials in the atmosphere that it has been enveloping the world in the ash roof for millions of years while simultaneously blocking sunlight, ozone depleting , falling acid rain and rising temperatures.

Now scientists have demonstrated what has eradicated marine life: rising temperatures accelerate the metabolism of ocean creatures, which increases their oxygen demand while exhausting the oceans of oxygen.

The animals literally suffocated.

Today we are again experiencing similar warming of the atmosphere – much faster than the Great Death, which showed warning signs 700,000 years before the event itself.

"This is the first time," explains oceanographer Justin Penn of the University of Washington, "that we have made a mechanistic forecast of what caused the disappearance, which can be tested directly with fossils, which then allows us to make predictions of causes for extinction in future. "

The team conducted a computer simulation of the changes the Earth experienced during the Great Death. Prior to the Siberian volcanic eruptions, temperatures and oxygen levels were similar to those present today to give them a good basis for work.

Then they raised the greenhouse gases in the atmosphere to mimic conditions after the eruption, which raised sea surface temperatures by about 11 degrees Celsius (20 degrees Fahrenheit).

Of course, this resulted in an oxygen depletion of about 76 percent – and about 40 percent of the seabed, mostly at greater depths, was completely depleted by oxygen.

To see how this would affect marine life, the team included in the simulation data on the need for oxygen from 61 modern species. It was a disaster.

"Very few marine organisms remained in the same habitats they lived in – either fleeing or dying," says oceanographer Curtis Deutsch of the University of Washington.

The most heavily affected are creatures that are most sensitive to oxygen, with the most obvious devastation at high latitudes, far from the equator. When the team compares its result with fossil data, it confirms their findings.

This is because animals living in the warmer waters around the equator may migrate to higher latitudes where they will find habitats similar to those they have just left. But animals that already live in higher latitudes have no place to go.

Overall, according to researchers, this represents more than 50 percent of the loss of marine diversity in the Big Dying. The rest may have been caused by other factors such as AC oxidation2 of Siberian traps and a sharp decline in plant life caused by ozone thinning.

We have to sit and pay attention to this, the researchers said. This temperature increase of 11 degrees Celsius has taken several thousand years.

Since 1880, Earth's average temperature has risen by 0.8 degrees Celsius (1.4 degrees Fahrenheit), and two thirds of this increase has occurred since 1975. And the warming of the oceans is accelerating.

"In the scenarios of emissions that occur in the usual way, by 2100, warming in the ocean will reach 20% of warming at the end of Permia, and by 2300 will reach between 35 and 50%," said Pen.

"This study highlights the potential for mass extinction resulting from such a mechanism in anthropogenic climate change."

Do not forget that.

The team's research has been published in the magazine science,


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