We finally know what killed marine life in the most deadly mass extinction of history

About 252 million years ago, the Earth experienced catastrophic devastation – an extinction event so serious that it has wiped out almost all life on Earth.

Nearly 70% of all terrestrial vertebrate species were killed and 96% of all marine species, including the famous trilobite that had previously survived two other cases of mbad extinction.

This is what is called the Permian-Tribadic extinction event, also known as the dying great, and to our knowledge, it was the most significant event. calamitic of the history of the Earth.

It is widely accepted that climate change is to blame – more precisely because of the long-term volcanic activity in Siberia that dumped so much material into the atmosphere that it enveloped the world in a veil of ash during a million years, simultaneously blocking solar light and slimming ozone. , fall of acid rain and rise of temperature.

Now, scientists have demonstrated what was erasing marine life: Rising temperatures have accelerated the metabolism of ocean creatures, which has increased their oxygen needs, while reducing the oceans of oxygen.

The animals literally choked.

And we are experiencing the same atmospheric warming again today, but much faster than the Great Dying, which had shown warning signs 700,000 years before the event.

"This is the first time," said oceanographer Justin Penn of the University of Washington, "that we have made a mechanistic prediction of the cause of this extinction that can be directly tested with the fossil record, which we then allows to make predictions about the causes of extinction in the future ".

The team conducted a computer simulation of the changes the Earth experienced during the Great Death. Before the Siberian volcanic eruptions, the temperatures and oxygen levels were similar to what they are today, which gave them a good working base.

They then increased the greenhouse gases in the atmosphere of the model to mimic the conditions that followed the eruption, which resulted in an increase in sea surface temperature. about 11 ° C (20 ° F).

In fact, this resulted in an oxygen depletion of about 76% – and about 40% of the seabed, mainly at greater depths, was completely depleted of oxygen.

To observe the impact of this situation on marine life, the team integrated data on the oxygen requirements of 61 modern species into the simulation. It was a disaster.

"Very few marine organisms have remained in the same habitats that they lived in, whether fleeing or endangered," said oceanographer Curtis Deutsch of the University of Washington .

The most affected are the most oxygen – sensitive creatures, with the heaviest devastations being observed at high latitudes far from the equator. When the team compared their results with the fossil record, the results were confirmed.

Indeed, animals living in warmer waters around the equator can migrate to higher latitudes, where they will find habitats similar to those that they have just left. But animals that already live at higher latitudes have nowhere to go.

The researchers found that this accounted for more than 50% of Great Dying's loss of marine diversity. The rest was probably caused by other factors such as acidification by CO₂ Siberian traps, and a sharp decline in plant life caused by the depletion of the ozone layer.

We should sit and pay attention to that, said the researchers. This temperature increase of 11 degrees Celsius took a few thousand years, roughly.

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

"According to a usual emissions scenario, by 2100, warming in the upper layer of the ocean will have approached 20 percent by the end of the Permian, and by now the 39. in the year 2300, it will reach between 35 and 50 percent, "Penn said.

"This study highlights the potential for mbad extinction arising from a similar mechanism in the context of anthropogenic climate change."

Remember this.

The research of the team was published in the journal Science.