“Toxic soup” contributed to the worst mass extinction on Earth (and it seems to be happening again)

Posted:

Sep 20, 2021 05:06 GMT

Researchers warn of the similarities our time has with the devastating events that ended almost all of life during the Permian, 252 million years ago.

An international team of scientists has identified a new cause for many mass extinction events that have occurred throughout Earth’s history, during which microorganisms start to proliferate uncontrollably in fresh water sources and turn it into a “toxic soup” that ends with life, states a recent study published in the journal Nature Communications.

Studying the fossil record of rocks near Sydney, Australia, researchers found that the Permian extinction 252 million years ago – the largest in Earth’s history – appears to be linked to growth bacteria and algae. While these organisms are important to the ecosystem, if they grow uncontrollably, they deplete oxygen and can even release toxins into the water.

The authors explain that the three main ingredients in the formation of this “toxic soup” are accelerated emissions of greenhouse gases, high temperatures and abundance of nutrients. The volcanic eruptions of the time contributed to the first two conditions, while sudden deforestation caused the third. In addition, once the food chain was severed, algae and bacteria continued to advance, delaying their recovery for millions of years.

The same recipe

These events meant that in the Permian almost all species in the oceans and on land were extinct. But what worries scientists the most is that humans seem to be following this same recipe and that freshwater microbial blooms are on the rise.

“There are a lot of parallels with today”, warned Tracy Frank, a researcher at the University of Connecticut. The scientist stressed that “we are seeing more and more toxic algal blooms in lakes and shallow marine environments”, linked to changes in ecosystems and increased temperatures due to human activity.

The researchers also noted other similarities, including forest fires and land destabilization. “One of the things that destroyed entire ecosystems was fire, and we’re seeing it right now in places like California. You wonder what the long-term consequences of events like this are as this happens. ‘they are becoming more and more prevalent,’ said geologist Chris Fielding.

“The mass extinction event at the end of the Permian took four million years to recover. That’s something to think about,” Fielding reflected, referring to the clear symptoms of an unbalanced ecosystem.