Latest news with #GreatDying
Observer
15-05-2025
- Science
- Observer
Glendonites after the end Permian mass extinction
The end of Permian mass extinction occurred 251.9 million years ago, marking the close of a geological period known as Permian. This extinction event is known as the greatest mass extinction recorded in the Earth's history. It is often called the Great Dying - an event when life was on the brink of vanishing, stranding few survivors stumbling both on land and in the ocean. Scientists believe this extinction event was triggered by an enormous volcanic eruption known as the Siberian Traps Large Igneous Province. The volcanic eruption emitted massive amounts of greenhouse gases into the atmosphere, warming the planet drastically and leading to substantial environmental changes that had a profound impact on life. Our recent field-based research has explored marine carbonate rock exposures dating back to this extinction event in the vicinity of the Qurayat area, Oman, and revealed the occurrence of unusual clusters of calcite aggregates that look like glendonites. Glendonites are altered forms of carbonate crystals formed from another mineral called ikaite. What is fascinating is that glendonites have never been reported from this specific time interval before, making our findings the first report. Normally, ikaite forms in near-freezing water conditions and is typically found in polar or nearby areas. However, the time of the extinction event was marked by extreme global warming, and the sediments we examined were laid down in warmer tropical conditions. To us, this presents a fascinating puzzle about how these unusual calcite crystal aggregates ended up in such a warm environment during such extreme warming. Musaab Al Sarmi Scientists have few ideas about why glendonites might appear during warmer periods. One idea is that cold spells (short bursts of very cold weather) could have played a role. Another possibility is that upwelling (rising water from the ocean's depth) of very cold water or cold water masses coming from polar regions allows glendonites to form in unusual places. Additionally, experiments in the lab have shown that ikaite crystals can form at much higher temperatures, as high as 35°C, which is far beyond its typical temperature for their formation when the water is very alkaline (with a pH above 9). This raises the question of whether one of these cases could explain why these carbonate crystal aggregates were found during the end of the Permian mass extinction. It seems less likely that a short pulse of a very cold period contributed to the formation of identified carbonate crystal aggregates. This is supported by research on oxygen isotopes from conodont remains - ancient eel-like marine animals that lived in the ocean million years ago - which shows that the ancient temperature of surface seawater rose quickly back then. However, through microscopic analysis of these calcite crystal aggregates, our study has shown that the ocean's conditions during that time were quite unusual. Seawater had a higher alkalinity level and a pH level above 9, meaning the ocean water was much more basic back then. This could mean that the calcite aggregates could have formed at higher temperatures, as shown in experiments. However, there is no evidence that glendonites can naturally form in highly alkaline water, and those made in the lab were formed under conditions that do not occur in nature. We also found evidence of the upwelling process indicated by fossil content. This suggests that unusual ocean chemical states, possibly along with the upwelling of very cold water, may have played a role in the formation of these intriguing carbonate crystal aggregates. Overall, this research, along with many others, highlight how unusual ocean chemistry was during the End-Permian mass extinction, driven by extreme global warming, which critically impacted ocean life.
Yahoo
28-03-2025
- Science
- Yahoo
Earth's 5 catastrophic mass extinctions, explained
While life on Earth does usually find a way, it is not without some intense past–and future–periods of mass death. Extinction is not exclusive to dinosaurs. Our planet has gone through at least five periods of mass extinction, with the planet likely in a sixth wave of mass extinction–this one, driven by humans. Our planet's first known mass extinction happened about 440 million years ago. Species diversity on Earth had been increasing over a period of roughly 30 million years, but that would come to a halt as water began to freeze in a massive ice cap towards the south pole. The formation of the Appalachian Mountains was the potential cause of this cooling. When the supercontinent Gondwanaland collided with what is now North America, the ancient lapetus Ocean closed over a period of about 150 million years. The weathering of the freshly uplifted rocks from this continental collision may have sucked carbon dioxide out of the atmosphere. As a result, the planet drastically cooled, sea levels plummeted, and roughly 85 percent of species were wiped out. Due to this drop in sea levels, it was particularly hard on marine species including brachiopods, corals, and trilobites. Earth's marine species, especially those at the tropics, were in trouble again about 419 million to 365 million years ago. This series of mass extinctions during the Devonian period eventually eliminated about 75 percent of life. However, some of Earth's oldest fish called coelacanths make it out unscathed. There was likely not a single definitive cause of this period of mass extinctions, but oxygen levels in the ocean continually dropped at this time. A combination of several major stresses including excessive sedimentation, rapid global warming or cooling, impacts from comets or meteorites, volcanic activity, or massive nutrient runoff from the continents may have caused these pulses of extinction. [Related: The 'living fossil' that thrived during a mass extinction.] Interestingly, plants on land may have played a role. Some of the plants had adaptations including using the stem-strengthening compound lignin and a vascular structure. Both traits allowed them to grow and for their root systems to go deeper than they had before. As a result of these deeper roots, rock weathering may have increased. Earth's largest mass extinction, often referred to as the 'Great Dying,' occurred about 252 million years ago. Massive volcanic eruptions triggered catastrophic climate changes that altered the planet's entire biosphere. Over roughly 60,000 years, 96 percent of Earth's marine species and about three of every four land species were wiped out. Unfortunately, the Great Dying is the extinction event that most closely parallels Earth's current environmental crisis. 'Both involve global warming related to the release of greenhouse gasses, driven by volcanoes in the Permian and human actions currently,' paleontologist Christian Kammerer told Popular Science in a 2023 interview. '[They] represent a very rare case of rapid shifts between icehouse and hothouse Earth. So, the turmoil we observe in late Permian ecosystems, with whole sections of the food web being lost, represents a preview for our world if we don't change things fast.' Yet, some species managed to survive. A group of primitive amphibians called the temnospondyls may have gotten by through feeding on freshwater prey that larger land-based predators couldn't get to. It also helped that they weren't picky eaters. Life began to rapidly diversify after the Great Dying, but it still struggled. Large volcanic eruptions triggered the Triassic-Jurassic Extinction about 201 million years ago. Carbon dioxide levels rose yet again, acidifying the oceans and warming Earth by an average of five to 11 degrees Fahrenheit. As a result, up to 80 percent of all terrestrial and marine species went extinct. Crocodilians were much larger and more diverse than they are today. They were also dominant terrestrial species, but most of them died out. Both the Great Dying and Triassic-Jurassic extinctions ultimately paved the way for dinosaurs to dominate Earth. And we know how that went. About 66 million years ago, a large space rock slammed into the Earth off the coast of the present-day Yucatán Peninsula of Mexico. The impact from this almost seven-mile wide asteroid generated huge tsunamis and plumes of dust, debris, and sulfur being hurled up into the atmosphere. All of this excess material brought on severe global cooling, while wildfires ignited within 900 miles of the impact. The crater formed by the asteroid strike was about 120-miles wide. [Related: June was probably a terrible month to be a dinosaur. Here's how we know.] As ecosystems collapsed, roughly 75 percent of all the existing plant and animal species went extinct. All non-avian dinosaur species were wiped out in what is arguably the most famous mass extinction in Earth's history. With most dinosaurs gone, mammals diversified and took over, paving the way for the ecosystem we see today.
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.
Yahoo
05-03-2025
- Science
- Yahoo
Earth's ‘Great Dying' killed 80-90% of life. How some amphibians survived.
When we talk about mass extinction events, the first case that usually comes to mind is when an asteroid struck Earth about 66 million years ago and triggered the extinction of the dinosaurs. However, the Cretaceous–Paleogene extinction event was not the worst loss of life in our planet's history. That distinction belongs to the Permian-Triassic extinction or the Great Dying. During this dramatic period of climate change about 252 million years ago, about 80 to 90 percent of all species on Earth were wiped out and the biosphere of the planet was completely altered. Yet still, in the face of this devastation, some species managed to survive. Namely, a group of primitive amphibians called the temnospondyls. They may have survived the Great Dying by feeding on some freshwater prey that larger land-based predators couldn't get to and by not being picky eaters. These new findings are detailed in a study published March 4 in the journal Royal Society Open Science. About 250 million years ago during the Early Triassic, nearly constant volcanic activity led to long phases of global warming, aridification, reductions in oxygen in the atmosphere, mega El Niños, acid rain, and wildfire. The landscape eventually became so hostile that the tropics became completely devoid of animal life. The eventual tropical dead zone impacted the distributions of both marine and terrestrial organisms throughout Earth. Some organisms, including sharks, horseshoe crabs, and temnospondyls, managed to tough it out. 'One of the great mysteries has been the survival and flourishing of a major group of amphibians called the temnospondyls,' Aamir Mehmood, a study co-author and evolutionary biologist at the University of Bristol in the United Kingdom, said in a statement. 'These were predatory animals that fed on fishes and other prey, but were primarily linked to the water, just like modern amphibians such as frogs and salamanders. We know that climates then were hot, and especially so after the extinction event. How could these water-loving animals have been so successful?' To figure out why, Mehmood and the team from this new study collected fossil data from 100 temnospondyls that lived throughout the Triassic. They studied how their ecologies changed, measuring parts of their skulls, teeth, and body sizes to see what specific functions they may have been used for. Surprisingly, they found that the temnospondyls did not change much throughout the crisis. Instead, they showed the same range of body sizes that they did during the earlier days of the Permian period. Some of the temnospondyls were small and fed on insects while others were larger. These bigger temnospondyls hold a critical survival clue. 'These larger forms included long-snouted animals that trapped fishes and broad-snouted generalist feeders,' study co-author and paleontologist Armin Elsler said in a statement. 'What was unusual though was how their diversity of body sizes and functional variety expanded about 5 million years after the crisis and then dropped back.' Due to the intense global warming in the first five million years of the Triassic period, there is evidence both terrestrial and marine organisms moved away from the tropics to get away from the extreme heat. According to the team, the temnospondyls were surprisingly able to cross that tropical dead zone. [ Related: These pleasantly plump salamanders dominated the Cretaceous period. ] 'Fossils are known from South Africa and Australia in the south, as well as North America, Europe and Russia in the north,' study co-author and paleontologist Mike Benton said in a statement. 'The temnospondyls must have been able to criss-cross the tropical zone during cooler episodes.' The study suggests that their generalist feeding ecology was key to this success. Temnospondyls were able to feed on a variety of prey, despite the environmental changes happening around them. It wasn't that they could survive by eating less, but also their ability to hide in sparse water bodies and consume different types of prey. However, this success did not last. The temnospondyls began their decline by the Middle Triassic, as the ancestors of mammals and dinosaurs began to diversify. 'Their burst of success in the Early Triassic was not followed up,' said Mehmood. Temnospondyls ultimately went extinct about 120 million years ago. While they do not have any living relatives, some evolutionary biologists do consider them an important step towards today's diverse amphibians. Studying these past periods can help scientists understand how frogs, salamanders, and toads may fare during today's environmental challenges. Amphibians remain one of the most threatened groups of animals due to widespread diseases and climate change.
