Latest news with #end-Permian
Yahoo
15-03-2025
- Science
- Yahoo
The 'Great Dying' — the worst mass extinction in our planet's history — didn't reach this isolated spot in China
When you buy through links on our articles, Future and its syndication partners may earn a commission. The mass extinction that killed 80% of life on Earth 250 million years ago may not have been quite so disastrous for plants, new fossils hint. Scientists have identified a refuge in China where it seems that plants weathered the planet's worst die-off. The end-Permian mass extinction, also known as the "Great Dying," took place 251.9 million years ago. At that time, the supercontinent Pangea was in the process of breaking up, but all land on Earth was still largely clustered together, with the newly formed continents separated by shallow seas. An enormous eruption from a volcanic system called the Siberian Traps seem to have pushed carbon dioxide levels to extremes: A 2021 study estimated that atmospheric CO2 got as high as 2,500 parts per million (ppm) in this period, compared with current levels of 425 ppm. This caused global warming and ocean acidification, leading to a massive collapse of the ocean ecosystem. The situation on land is far hazier. Only a handful of places around the world have rock layers containing fossils from land ecosystems at the end of the Permian and beginning of the Triassic. A new study of one of these spots — located in what is now northeastern China —revealed a refuge where the ecosystem remained relatively healthy despite the Great Dying. In this place, seed-producing gymnosperm forests continued to grow, complemented by spore-producing ferns. "At least in this place, we don't see mass extinction of plants," study co-author Wan Yang, a professor of geology and geophysics at the Missouri University of Science and Technology, told Live Science. The finding, published Wednesday (March 12) in the journal Science Advances, adds weight to the idea that the Great Dying was more complicated on land than in the seas, Yang said. Yang and his colleagues looked at rock layers in Xinjiang that span the mass extinction event. A major advantage of this now-desert site is that the rocks include layers of ash that hold tiny crystals called zircons. The zircons include radioactive elements — lead and uranium — that gradually decay, which enables researchers to determine how long it has been since the crystals formed. This means the researchers can more accurately date the rock layers here than they can at other sites. Some of these layers also hold fossil spores and pollen. These fossils reveal that there wasn't a massive die-off and repopulation but a slow changeover of species, Yang said. This is consistent with other evidence from Africa and Argentina, where plant populations seemed to have shifted gradually rather than dying off dramatically and then repopulating, said Josefina Bodnar, a paleobotanist at the National University of La Plata in Argentina who was not involved in the research. Land plants "have a lot of adaptations that allow them to survive this extinction," Bodnar told Live Science. "For example, [they have] subterranean structures, roots or stems, that can survive perhaps hundreds of years." Seeds can also persist a long time, she added. This survival may have been particularly possible at humid, high-latitude regions. The site in Xinjiang was once dotted with lakes and rivers, a few hundred miles from the coast. Other places where plant refuges have been found, such as Argentina, were also high-latitude in the Permian, far from the equator where temperatures were the hottest. Yang and his colleagues found that during the late Permian and early Triassic, the climate became a bit drier in what is now Xinjiang — but not enough to cause deforestation. This may have been a consequence of location, said Devin Hoffman, a researcher in paleontology at University College London who was not involved in the new study. Marine animals had no escape from global ocean acidification. But climate change on land wasn't uniform. The impact would have been most pronounced in the center of Pangea, which was a vast desert. This means that in more temperate regions on land, survival could have been possible, Hoffman told Live Science. "You essentially have everything being pushed toward the poles and towards the coast, but on land you're able to escape some of the effects," he said. These findings have led to some debate over whether the greatest mass extinction ever deserves the moniker on land. "I will call it a crisis on land. I will not call it an extinction," said Robert Gastaldo, an emeritus professor of Geology at Colby College who was not involved in the new study, but who has collaborated with Yang in the past. RELATED STORIES —The five mass extinctions that shaped the history of Earth —How the Great Dying set the stage for the dawn of the dinosaurs —Fearsome saber-toothed giant dominated at dawn of 'Great Dying', but its reign was short-lived The end-Permian extinction is particularly interesting to scientists because it was driven by greenhouse gases, much like climate change today. The situation was far more extreme then: The polar ice caps melted completely — a situation that would cause sea levels to rise a staggering 230 feet (70 meters) today. But humans may be nearly as deadly as giant volcanoes. A 2020 study, for example, found that a smaller extinction event at the end of the Triassic (201 million years ago) was driven by greenhouse gas pulses from volcanoes that were on a similar scale to what humans are expected to emit by the end of this century. Studying these ancient catastrophes can give us a sense of what to expect under atmospheric carbon dioxide levels people have never experienced, Gastaldo said. "The planet has experienced it," he said. "The planet's memory is in the rock record. And we can learn from the rock record what happens to our planet under these extreme conditions."
Yahoo
12-03-2025
- Science
- Yahoo
The remote locale that shielded plants during Earth's biggest mass extinction
During a cataclysmic mass extinction event, there are typically not many places to hide. However, a region of the mountainous Turpan-Hami Basin in the Xinjiang Autonomous Region in Western China may have been an oasis for some living organisms during the planet's largest mass extinction. The spot may have served as a refugium–or life oasis–for terrestrial plants during the end-Permian mass extinction, when 80 to 90 percent of life on Earth was wiped out about 252 million years ago. These new findings are detailed in a study published March 12 in the journal Science Advances and challenges some of the views that land-based ecosystems saw the same major losses as marine environments during this incredibly turbulent time in our planet's natural history. During the end-Permian mass extinction––also called the Great Dying–80 percent of marine species were wiped out. While most species on land did not fare much better, the scope of terrestrial impacts has been debated by scientists. One prevailing theory suggests that massive volcanic eruptions in present-day Siberia triggered widespread devastation on land through wildfires, acid rain, and toxic gases. The extinction of Gigantopteris plants in South China and across the ancient supercontinent Gondwanaland around 252 million years ago helps bolster this argument. [ Related: Mega El Niños helped kill 90 percent of life on Earth. ] However, another theory argues that latitude and atmospheric circulation may have limited the effects of acid rain, wildfire, and toxic gases in certain regions. Some fossils suggest that some Mesozoic plants even existed before the mass extinction event, which could be evidence of uninterrupted evolution. In this new study, a team of scientists from institutions in the United States, Tibet, and China used fossil evidence of a terrestrial plant community that appears to have remained largely intact throughout the extinction event. This allowed the plants to continuously evolve and recover from any losses more quickly. The team looked at the South Taodonggou section of the Turpan-Hami Basin in Xinjiang. They used detailed analysis of fossil pollen and spores and a new geological dating method developed by Missouri University of Science and Technology geologist Wan Yang. From this dating technique and fossil analysis, it appears that the riparian fern fields and coniferous forest here continually thrived from 160,000 years before the extinction event began until 160,000 years after it ended. 'The presence of intact tree trunks and fern stems further confirms that these microfossils represent local vegetation, not transported remnants,' Mingli Wan, a study co-author and paleobotanist at the Nanjing Institute of Geology and Palaeontology (NIGPAS) of the Chinese Academy of Sciences, said in a statement. While some plant species did disappear locally, the team found that the overall extinction rate of spore and pollen species in South Taodonggou may have been only 21 percent. This percentage is significantly lower than the marine extinction rate during the same period, which saw about 80 percent of life wiped out. According to the team, this stable base of vegetation was crucial for the local ecosystem's recovery. Fossil evidence shows that this area was home to numerous tetrapods, small four-limbed vertebrates that include today's living amphibians, reptiles, birds, and mammals. The region was home to a plant eating tetrapod called Lystrosaurus and carnivorous chroniosuchians, which shows that the food web became more complex fairly quickly. The new evidence suggests the area recovered more than 10 times faster than in other regions of the world. The area's stable, semi-humid climate may have been the reason behind this great biological resilience. South Taodonggou consistently received about 100 millimeters of rainfall per year, which helped build abundant vegetation and a more habitable environment than other regions after the end-Permian mass extinction. All of this plant life offered vital support for migrating animals. Its proximity to the volcanic activity that triggered the end-Permian extinction also allowed the Turpan-Hami Basin shelter for crucial biodiversity. 'This suggests that local climate and geographic factors can create surprising pockets of resilience, offering hope for conservation efforts in the face of global environmental change,' Feng Liu, a study co-author and paleontologist at NIGPAS, said in a statement. According to the authors, the current concerns about the planet entering another mass extinction–one driven by human activity–highlights the importance of identifying and protecting areas like this that could protect life.
