On the other side of the coin, we have processes that have caused the destruction of life. In fact, there have been multiple extinction events in Earth’s past, including the largest such event, the end-Permian extinction, which wiped out 95% of all marine species on Earth. Occurring not long after, scientists found a smaller but nonetheless impactful extinction event called the Carnian Pluvial Episode or CPE. And they have been working to understand that smaller event that came during a time period when our planet was in the midst of recovering from the end-Permian.
The CPE was not a stunning, swift die-off like the other event I already mentioned or the later dinosaur-killing event, and it took scientists working across multiple disciplines to piece together an overview. As they’ve grown to understand the CPE, it turns out that 1) it’s a bigger extinction event than previously thought and 2) it directly led to the ascendency of the dinosaurs.
This most recent work, published in Science Advances, looked at the rainfall from this event. Per the press release: The CPE is named for the stage of the Late Triassic in which it occurred—the Carnian—and for its signature feature: rain. A lot of rain, in four main pulses lasting over a million years, fell across much of the supercontinent of Pangaea.
Along with all the rain, there was global warming as well as ocean anoxia and acidification, killing off a third of the marine species that were left or rose after the end-Permian and leading to further diversification of the remaining species. Study co-author Mike Benton noted that this period led to “the rise of modern reefs and plankton in the oceans and the rise of modern tetrapod groups, including frogs, lizards, turtles, crocodilians, dinosaurs, and mammals…along with some important plant groups such as conifers, and some new groups of insects.”
Dinosaurs are the forerunners of our modern-day birds, so this little-known extinction event actually played a key role in modern ecosystems. One more piece of the puzzle for life here on Earth.
“Extinction and dawn of the modern world in the Carnian (Late Triassic),” Jacopo Dal Corso et al., 2020 Sept 16, Science Advances