Climate crisis 233m years ago reshaped life on Earth, say scientists [View all]

[muriel_volestrangler]

But while the crisis 233m years ago wiped out great segments of life, it set the stage for the dinosaurs to take over, and for some of the first mammals, crocodiles and turtles to extend their ranges.

“There was clearly a mass extinction that we now call the Carnian Pluvial Episode, which was a bit hidden and mystical,” said Mike Benton, a palaeontologist at Bristol University. “It brought an opportunity for the dinosaurs, which would have been the obvious things you would see, but also mammals, turtles and others.”

Jacopo Dal Corso, who worked on the project at Leeds University, said geochemical signatures from the time point to massive volcanic eruptions which pumped vast amounts of greenhouse gas into the air. These drove repeated spikes in global warming. Dal Corso traced them back to the Wrangellia province of western Canada, where Triassic eruptions ejected volcanic basalt that now forms much of the west coast of North America.
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The mass extinction, which adds to the “big five” recorded over the past 500m years, hit the oceans hard, wiping out an estimated third of marine life. The destruction cleared the way for modern coral reefs and groups of plankton as life on Earth reset, the authors write in Science Advances.

https://www.theguardian.com/science/2020/sep/16/climate-crisis-233m-years-ago-reshaped-life-on-earth-say-scientists

Extinction and dawn of the modern world in the Carnian (Late Triassic)

The Carnian Pluvial Episode (Late Triassic) was a time of global environmental changes and possibly substantial coeval volcanism. The extent of the biological turnover in marine and terrestrial ecosystems is not well understood. Here, we present a meta-analysis of fossil data that suggests a substantial reduction in generic and species richness and the disappearance of 33% of marine genera. This crisis triggered major radiations. In the sea, the rise of the first scleractinian reefs and rock-forming calcareous nannofossils points to substantial changes in ocean chemistry. On land, there were major diversifications and originations of conifers, insects, dinosaurs, crocodiles, lizards, turtles, and mammals. Although there is uncertainty on the precise age of some of the recorded biological changes, these observations indicate that the Carnian Pluvial Episode was linked to a major extinction event and might have been the trigger of the spectacular radiation of many key groups that dominate modern ecosystems.

https://advances.sciencemag.org/content/6/38/eaba0099