Did Ancient Microbes Cause Earth’s Worst Mass Extinction?

Methanosarcina and the Great Dying - Permian Mass Extinction | Mysterious Universe: "About 252 million years ago, climate change killed almost every living species on Earth. The survivors made up roughly 10% of the species that existed prior to this catastrophic event, which scientists refer to formally as the Permian-Triassic extinction and more informally as the Great Dying."