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After the "Great Death" event 252 million years ago, how did life return to the seas?
What happened after the "Great Death" 252 million years ago... And what were the first creatures that came back to life?
Learn about the first animals that came back to life after the most dangerous extinction event in Earth's history
A new study published on June 29 of this year in the journal Science Advances showed that sediment feeders, such as worms and shrimp, which are animals that feed on organic matter settled on the ocean floor, were the first to return to life in number and biodiversity after the extinction event. The Permian–Triassic extinction event, which occurred approximately 252 million years ago, was called the "Great Death" because of the way it wiped out life on Earth and almost ended it.
mollusks ecosystem engineers
A report published on the Science Alret website reviewed the results of a new international research collaboration involving universities from China, the United States and the United Kingdom, and reported that suspended nutrients snacking on organic matter suspended in water were the first to come back to life after the "Great Extinction" event. .
Once the sediment nutrients had recovered to a sufficient degree, the suspended feeders followed (websites)
These organisms have multiplied in the corridors and burrows at the bottom of the South China Sea there, where researchers have found a wealth of fish fossils or archaeological excavations, which were not animal remains, but rather were remnants of animal activity.
In a press release published on the official website of the University of Bristol in the United Kingdom, paleontologist Michael Benton said: "We have been able to study fossil traces from 26 divisions and identify the entire chain of events representing a critical 7 million years of time."
"When we collected the details of 400 model points, we were able to construct the return stages of all animals, including benthos and swimmers, as well as soft-bodied animals that hide in ocean burrows," he added.
"The end of the Permian period was very devastating for life on Earth, which was caused by global warming and ocean acidification, but a species of mollusk was able to come back in a way that was not," said paleontologist Shuichen Feng of the China University of Geosciences. found in skeletal organisms.
"Our archaeological excavation data has revealed the resilience of soft animals in the face of rising carbon dioxide and warming. These ecosystem engineers may have played a role in restoring the benthic ecosystem after a massive mass extinction," he added.
It took 3 million years for mollusc sediments to return to levels before the 'Great Death' extinction (University of Bristol)
Gradually return to life
The team looked at 4 different metrics when measuring recovery: the different types of animals, how diverse they are, their use of ecological space, and how habitats have been modified by the animals.
The researchers found that life began returning first in the deep water, and once sediment nutrients recovered sufficiently, suspended nutrients such as brachiopods and bivalves, often rooted to the ocean floor, followed.
Later, coral reefs began to come back to life as well.
It took nearly 3 million years for the inhabitants of the mollusk sediments to return to pre-extinction levels.
“Perhaps the sediment nutrients were so messy on the sea floor that the water was contaminated with mud, or the coagulated mud meant that the suspension nutrients couldn't settle properly to the bottom of the sea,” says Alison Crabb, a graduate student in geobiology at the University of Southern California. The sea, or muddy water produced by these sediment feeders clog the filter structures of the suspended feeders and prevent them from feeding efficiently.”
The Permian-Triassic extinction event killed about 80-90% of marine life on Earth (Getty Images)
future scenario
The Permian-Triassic extinction event killed about 80-90% of marine life on Earth, so it's not surprising that recovery took so long.
The researchers believe that climate change, global warming, decreased oxygen and increased ocean acidification were the primary drivers behind the mass extinction, which of course means that the researchers' findings can paint a scenario for what will happen in the modern era.
By understanding how some animals survived and recovered in the aftermath of the Great Death, we can better understand how these organisms might survive our current warming period, and what species might be more resilient in responding to this event.