A new study reveals what caused most life on Earth to die out during the end-Permian extinction, also known as the Great Dying.
- A new paper claims to identify the cause of the Great Dying that occured nearly 252 million years ago.
- During the worst mass extinction event ever, most of Earth's life perished.
- The study suggests a volcanic eruption in Siberia spread aerosolized nickel particles that harmed organisms on the planet.
Dinosaurs are the most infamous victims of a mass extinction event 66 million years ago. But an even worse extinction happened 251.9 million years ago.
Called the end-Permian mass extinction or the Great Dying, this most severe of extinction events wiped out about 90 percent of the planet's marine species and 75 percent of terrestrial species. While scientists long have suspected it was initiated by volcanic eruptions in what is now Siberia, until now they haven't been able to explain exactly how so many species died out.
A new paper published in Nature Communications lays out the case that nickel particles that became aerosolized as a result of eruptions in the Siberian Traps region became dispersed through the air and water and were the cause of the ensuing environmental catastrophe. The paper pinpoints huge Norilsk nickel sulfide ore deposits in the Tunguska Basin that "may have released voluminous nickel-rich volcanic gas and aerosols into the atmosphere" as the start of the chain of events that led to the mass extinction.
The study is based on analysis of nickel isotopes that came from late Permian sedimentary rocks gathered from the Buchanan Lake section in the Sverdrup Basin in the Canadian High Arctic. What's notable about the rock samples is that they featured the lightest nickel isotope ratios ever measured, leading the scientists to conclude that the nickel came in the form of aerosolized particles from a volcano.
As the paper outlines, the only comparable nickel isotope values would be those from volcanic nickel sulfide deposits. The scientists write that of all the mechanisms that could result in such values, "the most convincing" explanation is that they got there as "voluminous Ni-rich aerosols" from the Siberian Traps large igneous province (STLIP).
The deadly effect of nickel particles
When the nickel got into the water, it wreaked havoc on the underwater ecosystem.
Co-author of the study, associate professor Laura Wasylenki of Northern Arizona University, explained that "nickel is an essential trace metal for many organisms, but an increase in nickel abundance would have driven an unusual surge in productivity of methanogens, microorganisms that produce methane gas. Increased methane would have been tremendously harmful to all oxygen-dependent life." This would have affected living creatures in and out of the water. The professor believes their data offers direct evidence that links nickel-rich aerosols, changes to the ocean, and the mass extinction that followed. "Now we have evidence of a specific kill mechanism," she added.
NAU associate professor Laura Wasylenki.Credit: Northern Arizona University.
Other theories on the Great Dying
Previous studies have pointed to other effects of the Siberian volcanic eruptions that likely contributed to the extinction event, including an overall warming of the planet, release of toxic metals, and acidification of the oceans, which likely killed off a number of species quickly. Others died out as a result of the depleted oxygen levels in the water.
"This domino-like collapse of the inter-connected life-sustaining cycles and processes ultimately led to the observed catastrophic extent of mass extinction at the Permian-Triassic boundary," said marine biogeochemist Hana Jurikova of the University of St. Andrews in the UK, who carried out a 2020 study on the end-Permian extinction. Her study looked at fossil shells from brachiopods in what is now the Southern Alps in Italy.
A reversal in Earth's magnetic field 42,000 years ago triggered climate catastrophes and mass extinctions. Can the field flip again?
About 42,000 years ago, Earth's magnetic field broke down temporarily, according to a new study. This lead to environmental cataclysms and mass extinctions, including the demise of the Neanderthals. The dramatic period was a turning point in Earth's history, claim the scientists, full of resplendent auroras, electrical storms, and strong cosmic radiation. These changes were caused by the reversal of the planet's magnetic poles and variations in solar winds.
Amusingly, the researchers behind the international study (which involved scientists from Australia, New Zealand, Switzerland, the U.K., Germany, U.S., Argentina, China, and Russia) called this period the "Adams Transitional Geomagnetic Event' or simply "Adams Event." The Adams they are referring to is the science fiction writer Douglas Adams, who famously wrote in "The Hitchhiker's Guide to the Galaxy" that 42 was the answer to "the Ultimate Question of Life, the Universe, and Everything."
Chris Turney, a professor at UNSW Sydney and co-leader of the study, remarked that their study was the first "to precisely date the timing and environmental impacts of the last magnetic pole switch."
Interestingly, their discovery was aided by ancient New Zealand kauri trees, which have been sitting preserved in sediments for more than 40,000 years.
"Using the ancient trees we could measure, and date, the spike in atmospheric radiocarbon levels caused by the collapse of Earth's magnetic field," said Turney.
What the trees helped the scientists understand were the effects of the magnetic pole switch, which was already known as "The Laschamps Excursion." Using radiocarbon dating to analyze the kauri tree rings, they could gauge how the planet's atmosphere changed.
Paleopocalypse! - Narrated by Stephen Fry.
The study's co-lead Professor Alan Cooper, Honorary Researcher at the South Australian Museum, highlighted the significance of the ancient trees to their work.
"The kauri trees are like the Rosetta Stone, helping us tie together records of environmental change in caves, ice cores and peat bogs around the world," explained Cooper.
Using the trees, the researchers were able to create global climate models that showed how the growth of ice sheets and glaciers across North America, differences in wind belts and tropical systems, and even the extinction of Neanderthals could all be linked to the climate changes brought on by the Adams Event.
"Earth's magnetic field dropped to only 0-6 per cent strength during the Adams Event," pointed out Professor Turney. "We essentially had no magnetic field at all – our cosmic radiation shield was totally gone."
According to the researchers, another fascinating consequence of the Adams Event is that early humans would have been both inspired and terrified by the amazing auroras seen in the sky, brought on by the magnetic field fluctuations. "It must have seemed like the end of days," said Cooper.
He also supposes that the calamities would have forced our ancestors into the caves, leading to the amazing cave art that came about approximately 42,000 years ago.
Could such a magnetic pole reversal happen today? Professor Cooper thinks there are some indications like the weakening of the field by 9 percent over the past 170 years that tells us a reversal may be coming.
"If a similar event happened today, the consequences would be huge for modern society," shared Cooper. "Incoming cosmic radiation would destroy our electric power grids and satellite networks."
Check out the study published in Science.
Rocks from two hundred million years ago show us how everything died and how nothing is new.
- A new study suggests that the mass extinction that gave dinosaurs the evolutionary upper hand was caused by oceanic oxygen deprivation.
- Using ratios of sulfur isotopes, researchers could estimate changes in ocean oxygen levels in ancient seas.
- The authors suggest a similar mechanism as that which can cause dead zones in oceans today caused a mass extinction.
Living on Earth isn't always easy. The fossil record is littered with enough mass extinction events to have once made theories that they occur in cycles seem feasible. The "Big Five" events each killed an average of 75 percent of all species alive at the time, with the largest one wiping more than 90 percent of them. While the question of what caused these events is interesting as a curiosity in and of itself, the problem also takes on an existential one, as most people would like to avoid the same fate as the trilobites.
To that end, a team of researchers based out of the UK, China, and Italy have investigated the causes behind one of the most massive die-offs in history. In a new paper published in Science Advances, they suggest a depletion in oxygen as a cause for the event at the end of the Triassic Era 201.3 million years ago.
How to tell what the world was like 201 million years ago using rocks
The mass extinction that ended the Triassic period was a massive die-off that saw somewhere between a quarter and a third of ocean life vanish alongside most large land animals. Plants were not spared a culling either, with perhaps 60 percent of plant species also dying. The event took less than 10,000 years to carry out this morbid work. This remarkable event paved the way for dinosaurs to become the dominant land animal during the Jurassic period, as most of their competition was dead.
Explanations for this event's cause have ranged from gradual climate change, to asteroid impacts, to rampant volcanism. New evidence suggests that ocean anoxia, the depletion of oxygen supplies in the ocean, played a large role.
The researchers examined the levels of two isotopes of sulfur in rocks that would have been on the seafloor during the extinction event from British Columbia, Sicily, and Northern Ireland. The two isotopes, 32S and 34S, can become trapped in limestone and other rocks and exist at different ratios depending on how much oxygen is in the water around them. By examining the changes in the ratio of the two isotopes in rocks formed at the time, we can know what was happening to oxygen levels in the oceans hundreds of millions of years ago.
The scientists noticed "large spikes" in the ratio of 34S to 32S in the samples from all of the locations, indicative of a substantial fall in the amount of oxygen available. These findings can be applied far beyond the sites the rock samples came from, suggesting that oxygen levels fell across large portions of the globe-spanning superocean, known as Panthalassa, that existed alongside Pangea.
And you thought the Dead Zone in the Gulf of Mexico was bad.
This study isn't the only one suggesting Ocean anoxia caused the extinction event. A previous study from 2017 reached a similar conclusion by measuring the trace uranium levels in rocks formed at the time. Similarly to the ratio of sulfur isotopes considered above, the amount of uranium in these rocks varies with the amount of oxygen. That study suggests that the low oxygen levels may have lasted 50,000 years after their initial fall, with a full 250,000 years needed before coral reefs could recover.
In the present day, the researchers hypothesize that this anoxia was connected to significant volcanic activity at the time. By releasing massive amounts of greenhouse gasses, this would have both acidified the oceans by increasing their carbon content and lowered their oxygen levels by raising global temperatures, as warm water holds less oxygen overall. Together, these effects can annihilate marine ecosystems. It is known that major volcanic activity was occurring at the time, lending credence to this hypothesis.
It's a good thing that nothing is causing the oceans to heat up and have lower oxygen levels these days! Oh, wait. Never mind.
If Arctic ice continues to melt at its projected rate, the bears will go extinct due to starvation by the end of the century according to a first-ever projected timeline.
- A new report on climate change by the University of Toronto is projecting that most of the polar bear population could reach extinction in under 100 years due to starvation.
- Polar bears are dependent on sea ice for hunting seals, a primary component of their diet. As temperatures rise and sea ice continues to shrink it has become increasingly challenging for the carnivores to hunt for food.
- The Arctic is likely to have warmed more than double the amount of the global average this year compared to pre-industrial temperatures.
If Arctic ice continues to melt at its projected rate, polar bears will go extinct by the end of the century according to a first-ever projected timeline.
An alarming new report on climate change is projecting that most of the polar bear population could reach extinction in under 100 years.
The University of Toronto published a study in Nature Climate Change last week that put a timeline on the beloved Arctic mammals' crisis for the first time. It's long been known that the ice habitats of polar bears — which most countries classify as an endangered species — have been rapidly melting, but now the "poster animal of climate change" has been given an extermination date by 2100.
Starving into extinction
Polar bears are dependent on sea ice for hunting seals, a primary component of their diet, and aren't exactly built for swimming to catch their prey in the open water. As temperatures rise and sea ice continues to shrink it has become increasingly challenging for the carnivores to hunt for food. The species could be starved out within the next 80 years, save for a few high-Arctic subpopulations.
"Here, we establish the likely nature, timing and order of future demographic impacts by estimating the threshold numbers of days that polar bears can fast before cub recruitment and/or adult survival are impacted and decline rapidly," the authors of the study said.
The study looked at 13 of the world's 19 subpopulations of polar bears that account for 80 percent of the species' total population. Researchers modeled the energy use of the polar bears to calculate the number of days the bears can fast before their reproductive abilities become impacted. They then mapped that onto the number of estimated iceless days that will be faced in the coming decades, determining that the amount of time the bears would be forced to fast surpassed the amount of time they were capable of fasting. In 20 years from now, some polar bears living in Canada will begin to face reproductive failure and in 40 years a majority of the global population will more than likely be affected.
"The dire predictions in our study result from polar bear's dependence on sea ice and the projected rapid loss of that ice due to human-driven climate change," Marika Holland, co-author of the paper told TIME.
While the scientists noted that moderate cuts in emissions could potentially extend the bears' estimated life-expectancy for a bit, it won't be able to save some species populations from extinction by the end of the century.
"Land-based feeding is unlikely to occur at scales that shift the timelines for recruitment and survival declines by more than a few years, because foods that meet the energy demands of polar bears are largely unavailable on land," the study said, pointing out that some polar bear populations are already feeling the impact.
The melting arctic
Of course, as the International Union for Conservation of Nature has cited, climate change is the main cause of the population's suffering and decline.
According to the World Meteorological Organization, the Arctic is likely to have warmed more than double the amount of the global average this year compared to pre-industrial temperatures. Since the 1970s, satellites have shown sea ice melting by 13 percent per decade. If greenhouse gas emissions stay on their current trajectory, the only polar bears that will be left by the end of the century will likely be those living in the Queen Elizabeth Islands in Canada's Arctic Archipelago.
Keeping tabs on polar bears, the largest land-dwelling carnivore on earth, is how scientists keep their finger on the pulse of the health of Arctic populations at-large. Their loss, as Holland told TIME, "would reverberate throughout the ecosystem."
But the bears won't go down without a fight for their survival. As Arctic temperatures rise, melting the species' normal hunting grounds, the bears may begin to move toward land to find food. For example, in 2019 authorities in Russia's remote arctic region declared a state of emergency as a mob of starving polar bears charged into villages.
Arctic foxes are another species endangered as their habitats and diets are threatened by melting sea ice due to greenhouse gas emissions.Photo by Jonatan Pie on Unsplash
Polar bears have faced extermination in the past. In 1965, scientists were worried that commercial polar bear hunting would cause the species to go extinct. A 1973 worldwide ban on hunting led to a resurgence in bear population, yet the melting sea ice that now threatens the lives of the estimated 26,000 that live on earth today is a much more complex issue to solve. While the species' future looks grim, the study does point out that decreasing fossil fuel burning may reduce Arctic sea ice loss.
If there is a sliver of hope left for the polar bears and other Arctic species endangered by melting Arctic ice, it rests on rapid and radical human action against fossil fuel emissions.
Scientists discovered footprints made by some of the largest creatures ever to walk the Earth.
- Paleontologists published a paper on the discovery of dinosaur footprints on the roof of a French cave.
- The prints are deep underground and were made during the Middle Jurassic period.
- The footprints belonged to titanosaurs, the largest land animals ever.
French scientists found gigantic dinosaur footprints on the roof of the Castelbouc cave the Lozère region of southern France. A new paper outlines the discovery approximately 1640 feet under ground by the paleontologist Jean-David Moreau from the University of Burgundy–Franche-Comté and his colleagues.
The footprints likely belonged to an unknown species of titanosaur and were made 166 to 168 million years ago, in the Middle Jurassic Period. Titanosaurs, a group of long-necked, lizard-like sauropods, could be found all over the world in present day Africa, the Americas, Europe, and Australia. Among titanosaurs were the largest land animals to have ever existed, like the Patagotitan, which stretched 121 feet long and weighed 138,000 pounds.
The titanosaur Alamosaurus.
Credit: Bogdanov, 2006. Creative Commons.
Some of the 38 tracks found in France were as large as 4 feet long. They were likely made by three dinosaurs at the time when the area was on the surface, making up a muddy shoreline along which the giant creatures traveled. Over time, the site was buried by geological processes, with the tracks becoming moldings in the roof of a cave that's half a kilometer underground.
They were spotted as part of a caving expedition in December 2015 by the paper's authors. To find them, the scientists had to go down a narrow labyrinth of crawl spaces that often get flooded. The tracks were in a space about 260 feet long, 66 feet wide and 33 feet high.
Dinosaur tracks in the ceiling of Castelbouc Cave in France.
Credit: Jean-David Moreau et al./J. Vertebr. Paleontol.
Speaking to the French science magazine Sciences et Avenir, Jean-David Moreau explained that a caver "who was ahead of me turned to me and with the lamp of his helmet projected a grazing lighting on the ceiling which allowed to bring out the marks."
You can read the paper "Middle Jurassic tracks of sauropod dinosaurs in a deep karst cave in France," published in the Journal of Vertebrate Paleontology.