Poison Bacteria Set Up Worst Extinction

In the three to four million years before the Permian-Triassic extinction, illustrated here, the seas were already oxygen-starved, according to a new study. The stagnant depths were a haven for bacteria that belched poison that crippled life on Earth, leaving it vulnerable to the volcanic knockout punch that would soon come. Lunar and Planetary Institute

From MSNBC:

New finding gets to heart of a long debate among extinction researchers.

In the ancient oceans, stagnant depths harbored poison-belching bacteria that crippled life on Earth, leaving it vulnerable to a knockout punch from volcanic eruptions, according to a new study.

Three to four million years before the Permian-Triassic extinction, also known as the Great Dying, the seas were already becoming oxygen-starved and sour, said the study in the journal Earth and Planetary Science Letters.

Changqun Cao of the Chinese Academy of Sciences in Nanjing and a team of researchers studied rock samples drilled in central China from the late Permian and early Triassic periods. Rocks from the extinction itself date to 252.2 million years ago, and show several chemical signs of catastrophe.

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