The mass extinction event at the end of the Permian period, approximately 252 million years ago, could repeat itself due to toxic blooms, but modern humans have the capability to prevent it.
The scientific news site Phys.org reported on September 17 that the mass extinction that nearly wiped out Earth at the end of the Permian could happen again. This mass extinction was associated with massive greenhouse gas emissions and rising Earth temperatures, leading to the disappearance of most terrestrial and marine animal species.
A study led by Professors Tracy Frank and Chris Fielding identified one of the causes of this mass extinction: the explosion of toxic bacterial species turning the air and water sources into a “toxic soup”, killing off animal species.
The algal bloom event killed many aquatic animal species. (Photo: Phys.org)
In a healthy ecosystem, algae and cyanobacteria release oxygen that supports aquatic life. However, when the populations of algae and cyanobacteria spiral out of control, they can deplete oxygen levels in the water and even release toxins.
By studying fossils, sediments, and the chemical origins of rocks near Sydney, Australia, researchers found that algal blooms occurred during the mass extinction at the end of the Permian period.
“Toxic soup” thrives further when supported by three factors: greenhouse gas emissions, high temperatures, and abundant nutrients. Volcanic eruptions contributed to the first two factors, while deforestation promoted the third. When trees are cleared, soils wash into rivers and lakes, providing all the necessary nutrients for bacterial growth.
According to Professor Frank, we are currently witnessing many types of toxic algae in rivers and lakes linked to rising temperatures and changes in plant populations that contribute nutrients to freshwater environments.
Climate change combined with water pollution, primarily from agriculture and deforestation, fosters the growth of toxic algae. Researchers also noted that the temperature increase at the end of the Permian coincided with a surge in wildfires. Now, severe wildfires, such as those in California, are becoming increasingly common. These are clear symptoms of an unbalanced ecosystem.
However, unlike past mass extinctions, modern humans can prevent toxic algae blooms by keeping water sources clean and controlling greenhouse gas emissions, thus averting a similar mass extinction.
