Biodiversity was significantly reduced during the Permian-Triassic mass extinction, as can be seen especially in body fossils of animals with complete skeletons. Both skeletonized and soft-bodied organisms can provide evidence to help us understand how entire ecosystems were affected by the crisis and then regenerated.
In a new study, scientists from China, the US and the UK uncover how the event brought life back to the ocean. They found that the animals were among the first to bounce back after the end-Permian mass extinction.
Scientists examine trails and caves on the South China Sea Bed. They could tie together the resurgence of marine life by describing what and when the animal’s movement was occurring.
Professor Michael Benton from the University of Bristol’s School of Earth Sciences, a collaborator on the new paper, said: “The end-Permian mass extinction and recovery of life in the early Triassic are very well documented throughout South China.”
“We were able to trace trace fossils from 26 volumes through the full chain of events, representing seven million critical years, and showing details at 400 sampling points; we finally reconstructed the recovery stages of all the animals.” , which included bentos, nekton, as well as these soft-bodied animals in the ocean.
Dr. Xueqian Feng of the China University of Geosciences in Wuhan led the study, focusing on ancient bastions and trails. he explained: “Trace fossils such as trails and burrows document mostly soft-bodied animals in the ocean. Most of these soft-bodied animals did not have skeletons or were poorly developed.
“There are some amazing areas in South China where we found a large number of beautifully preserved trace fossils, and the details may show anomalous ecosystem engineering behavior, as well as their feedback effects on the biodiversity of skeletal animals.”
Professor Zhong-Qiang Chen, director of the study, said: “Trace fossils show us when and where soft-bodied, burrowing animals flourished in this early Triassic greenhouse world.
“For example, elevated temperatures and extended anoxia coincide with lower values of behavioral and ecological diversity across the Permian–Triassic boundary. Took a million years.”
David Bottzer, associate professor in the study from the University of Southern California, said: “One of the most remarkable aspects of the South China data is the breadth of ancient environments we can sample.”
“Differential responses of unicellular ecosystems to variable environmental controls may have played an important but little appreciated evolutionary and ecological role in recovery in the warm Early Triassic Ocean.”
Another colleague, Dr. Chunmei Su, said: “The mass extinction killed more than 90 percent of species on Earth, and we see a catastrophic reduction in the ecological function of living animals in the ocean.”
“At first, only a few were left, and recovery began in deep water. Nekton’s recovery coincided with a complete rebound of simultaneous infaunal ecosystem engineering activities.”
Study associate Alison Cribb from the University of Southern California said: “The first animals to recover were deposit feeders such as insects and shrimp. The recovery of suspension feeders such as brachiopods, bryozoans, and many bivalves took much longer.
“Maybe the deposit feeders were making such a mess of the sea floor that the water was polluted with mud, the churned soil meant the suspension feeders couldn’t sit properly on the sea floor, or the filth produced by those deposit feeders.” The water had clogged the filtering structures of the suspension feeders and prevented them from feeding efficiently.”
Professor Chen said: “And some animals, such as corals, had disappeared entirely. Coral reefs did not return until much later.
Dr. Fang concluded: “Why is it important to understand these mass extinctions of the geological past?”
“The answer is that the end-Permian crisis – which was so devastating to life on Earth – was caused by global warming and ocean acidification, but the animals that make up the trace may have been selected by the environment in a way that skeletal organisms were not. . “
“Our trace fossil 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 benthic ecosystems after severe mass extinctions, potentially, e.g. For, triggering evolutionary innovations and radiations in the early Triassic.
Journal Reference:
- Xueqian Feng, Zhong-Qiang Chen, et al. Resilience of informal ecosystems during the Early Triassic greenhouse earth. Science Advances, 2022; 8 (26) DOI: 10.1126/sciadv.abo0597
