California University scientists in Riverside proposed a possible explanation of the largest mass extinction of 250 million years ago, at the end of the Perm period. According to their data, it could be associated with the release of microbes of toxic gases, which intensified due to global warming. This is reported in an article published in the journal Nature Geoscience.
It is known that the mass perm extinction was caused by major eruptions in Siberia, because of which a huge amount of carbon dioxide falls into the atmosphere. This led to global warming and heating of sea water, as well as a decrease in the level of oxygen dissolved in the ocean. In a new study, scientists have shown that as the temperature increases, EVCIN zones, characterized by the absence of oxygen and an increase in sulfide concentrations.
Evcin zones occur when bacteria begin to consume sulfate, and then highlight hydrogen sulfide, toxic for many animals. The dead living organisms decompose, spending dissolved oxygen and producing even more organic substances supporting the deadly cycle. At the end of the Perm period, this led to extinction of 80 percent of all marine species of living organisms, as well as many landings.