During our modern camera era, the Earth hasn’t been wildly active, and it’s easy to forget that past volcanic eruptions were capable of triggering global extinctions. 

Over 200 million years ago, at the boundary between the Triassic and Jurassic periods, 23-34% of all marine genera disappeared and on land entire classes of animals, including many of the giant reptiles of the time, died off. Past research indicated this may have been caused by massive volcanic eruptions and the release of flood basalts, but the mechanisms for the marine die-off were unclear. 

Now, in a new paper appearing in the journal Geology and led by Calum Fox, researchers detail the twin processes that could have killed off the Earth’s seas. According to Fox: These were a deadly combination of ocean acidification, which inhibited [the] growth of all marine life using calcium carbonate to create shells or body parts such as mussels, oysters, and corals, and rising levels of hydrogen sulfide in the ocean, which was extremely toxic for all marine life.

It all comes down to chemistry. At the end of the day, the gasses inside our world are toxic to the life atop our world.

More Information

Curtin University press release

“Two-pronged kill mechanism at the end-Triassic mass extinction,” Calum P. Fox et al., 2022 January 5, Geology