The Permian-Triassic extinction event, which occurred approximately 252 million years ago, is colloquially known as the Great Dying because of the way it wiped out life on Earth, almost ending it. completely. It is the most serious extinction in history.
Life recovered, however, and new research identifies that deposit feeders such as worms and shrimp, animals that feed on organic matter installed at the bottom of the ocean, were the first to recover. in terms of population and biodiversity.
Suspension feeders, which snack on water-suspended organic matter, followed much later, according to detailed dating of trails and burrows on the seabed of southern China. This analysis revealed a large number of ichnofossils or fossil traces, not real animal remains, but remains of animal activity.
How could the oceans have been before (A) and after (BF) extinction. (X.Feng / Z.-Q.Chen / MJ Benton / Y. Jiang)
“We have been able to observe fossil traces of 26 sections across the entire series of events, representing 7 million crucial years of time,” says paleontologist Michael Benton of the University of Bristol in the UK.
“Showing details at 400 sampling points, we finally reconstructed the recovery stages of all animals, including benthos, necton, as well as these soft-bodied animals in the ocean.”
Because soft-bodied animals have no skeleton to leave behind, fossil traces are vital to finding out how these creatures lived. The research team was also able to incorporate body fossils into their study to see how other species began to recover once the tank’s feeders were established.
“The end-of-Permian crisis, which was so devastating for life on Earth, was caused by global warming and ocean acidification, but the environment can select animals that make traces of ‘a way that skeletal organisms were not,’ says paleoecologist Xueqian. Feng University of Geosciences of China.
“Our fossil trace data reveal the resilience of soft-bodied animals to high CO2 and warming. These ecosystem engineers may have played a role in the recovery of the benthic ecosystem after severe mass extinctions.” potentially, for example, triggering evolutionary innovations and radiation in the early Triassic. “
The team analyzed four different metrics when measuring recovery: diversity (the different types of an animal), disparity (how varied these different types were), how space was used. of ecosystem) and how habitats were modified by the animal (ecosystem). engineering).
Life began to return to the deepest waters first. Once tank feeders had largely recovered, suspension feeders such as brachiopods, bryozoans, and bivalves, largely sedentary and often rooted on the ocean floor, followed, but much later.
Even later, the choirs began to return. The inhabitants of soft-bodied sediments took about 3 million years to return to pre-extinction levels.
“Maybe the tank feeders were making a mess of the seabed that the water was contaminated with mud, the beaten mud meant that the suspension feeders could not settle properly on the seabed, or the muddy water produced by those feeders of deposit only obstructed the filtration structures of suspension feeders and banned them from feeding efficiently, ”says geobiology graduate student Alison Cribb of the University of Southern California.
The Permian-Triassic extinction event killed about 80-90 percent of marine life on Earth, so it’s no surprise that recovery has taken a long time. By adding trace fossil records to the data along with body fossils, scientists can get a more complete picture of what happened next.
Climate change, global warming, a drop in oxygen, and rising ocean acidification are believed to be the main drivers of mass extinction, and of course this means that the findings here can help us. teach more about what is happening in the modern era.
By understanding how some animals survived and recovered after the Great Dying, we can better figure out how these creatures could survive the current warming period we are going through and which species might be the most resilient.
The research has been published in Science Advances.