Latest news with #GoetheUniversityFrankfurt
Yahoo
26-05-2025
- Science
- Yahoo
Giant Megalodon's Prey Finally Revealed, And It's Not What We Thought
Megalodon, the terror of the Neogene, dominated its giant shark niche for just 20 million years before it disappeared from the world's oceans. And, during that time, it hunted anything and everything that crossed its path. It didn't distinguish: if it was large enough to be a snack, megalodon (Odontus megalodon) partook. Scientists have reached that conclusion after studying the teeth of modern sharks, and comparing them to the fossilized teeth of megalodon, almost all we have left of the extinct fish today. This contradicts the theory that the main prey of megalodon was whales. Certainly megalodon could and did eat whales – but its diet as a whole was far more opportunistic. "Our study tends rather to draw a picture of megalodon as an ecologically versatile generalist," says geoscientist Jeremy McCormack of Goethe University Frankfurt in Germany "Megalodon was by all means flexible enough to feed on marine mammals and large fish, from the top of the food pyramid as well as lower levels – depending on availability." Megalodon is an extinct species of shark that lived from around 23 million to around 3.6 million years ago, during which time it occupied a prime position at the top of the food web, before being driven to extinction. We will never know for certain what it looked like; like all sharks, its skeleton was mostly cartilage, and all it left behind was a lot of teeth and a few vertebrae. We know from these remains, however, that megalodon was enormous, with size estimates ranging from around 11 meters to over 40 meters (36 to 131 feet) in length (although the latter is an outlier, and most estimates hover around 13 to 20 meters). That's huge – so huge that scientists think that megalodon may have specialized in large prey. One way to determine the diet of someone who has been dead a long time is to look at isotopes in their teeth. An isotope of an element is an atom that deviates from the norm in the number of neutrons it has in its nucleus, and the ratios of these isotopes vary according to several factors, one of which is diet. This is because when we eat, some of the metals in our food replace some of the calcium in our teeth and bones – not so you notice, obviously, but enough to leave a tracer. McCormack and his colleagues looked specifically at the ratios of two isotopes of zinc – the lighter zinc-64 and the heavier zinc-66. When fish at the bottom of the food web eat, they store less zinc-66 than zinc-64. The fish that eat those fish have even less zinc-66. So when you get to the fish at the very top of the chain, you see the very least zinc-66 compared to zinc-64. This is what the researchers observed in the teeth of megalodon and its cousin, the extinct Odontus chubutensis. The researchers don't really know what was at the bottom of the food chain 18 million years ago, the time from which the megalodon teeth they studied hailed. So, they compared the megalodon teeth with the teeth of sharks that swim the oceans today to work out what the giant predators ate. "Sea bream, which fed on mussels, snails, and crustaceans, formed the lowest level of the food chain we studied," McCormack says. "Smaller shark species such as requiem sharks and ancestors of today's cetaceans, dolphins, and whales, were next. Larger sharks such as sand tiger sharks were further up the food pyramid, and at the top were giant sharks like Araloselachus cuspidatus and the Otodus sharks, which include megalodon." Megalodon's status as a superpredator at the very top of the food web has been established previously. The new research reveals that the isotope difference between megalodon and the animals at the lowest level the researchers studied was not a sharp delineation, suggesting that the shark was not a fussy eater. There were also intriguing differences in megalodon diet depending on where the animals lived. Megalodon teeth found in Passau, Germany, dined more heavily on the lower levels of the food web, the researchers found. This is not dissimilar to the opportunistic hunting approach demonstrated by white sharks (Carcharias carcharodon), which stands to reason: previous work led by McCormack showed that the rise of the white shark was likely one of the drivers that led megalodon to extinction. With competition in its ecological niche, megalodon became more vulnerable. "It gives us important insights into how the marine communities have changed over geologic time," says paleobiologist Kenshu Shimada of DePaul University in the US, "but more importantly the fact that even 'supercarnivores' are not immune to extinction." The research has been published in Earth and Planetary Science Letters. Earth's Core Holds a Vast Reservoir of Gold, And It's Leaking Toward The Surface Scientists Peered Inside The Echidna's Mysterious 'Pseudo-Pouch' Bizarre Three-Eyed Predator Hunted The Ocean Half a Billion Years Ago
Newsweek
26-05-2025
- Science
- Newsweek
Megalodon: Largest Ever Shark's Diet Surprises Geoscientists
Based on facts, either observed and verified firsthand by the reporter, or reported and verified from knowledgeable sources. Newsweek AI is in beta. Translations may contain inaccuracies—please refer to the original content. A new study has uncovered surprising insights into the feeding habits of the largest predatory fish to ever roam the Earth's oceans, challenging long-standing assumptions about the prehistoric predator. For centuries, scientists believed that Otodus megalodon hunted exclusively at the top off the food chain, but a new study led by Jeremy McCormack from the Department of Geosciences at Goethe University Frankfurt found that its diet was far more flexible than previously thought. Longer than a truck with a trailer (reaching up to almost 79 feet long) and weighting almost twice as much, Megalodon, ruled the oceans between 20–3 million years ago, frequently on the hunt for prey to satisfy its astonishing 100,000 kilocalories-per-day nutritional demand. Its massive jaws were filled with triangular teeth, each the size of a hand, and its deadly bite had the force of an industrial hydraulic press, leaving no hope for any creature crossing its path. It was thanks to its fossilized teeth that McCormack, in collaboration with other scientists from Germany, France, Austria and the US, were able to discover the apex predator's unusual dietary habits. A stock image shows a 3D illustration of the Otodus Megalodon, the largest predatory fish that has ever existed. A stock image shows a 3D illustration of the Otodus Megalodon, the largest predatory fish that has ever existed. getty images By analyzing the levels of zinc in the fossils, the study found that while Megalodon did surely feast on whales and dolphins whenever it had a chance, the shark adjusted its diet based on availability of the prey. Zinc occurs in atomic variants (isotopes) of different weights, and is ingested with food. Less of the heavier isotope zinc-66 than the lighter isotope zinc-64 is stored in muscles and organs. Predatory fish absorb significantly less zinc-66 and those at the top of the food chain absorb even less. "Since we don't know how the ratio of the two zinc isotopes at the bottom of the food pyramid was at that time, we compared the teeth of various prehistoric and extant shark species with each other and with other animal species. This enabled us to gain an impression of predator–prey relationships 18 million years ago," explained McCormack in a statement. Sea bream—a fish which fed on mussels, snails and crustaceans—formed the lowest level of the food chain, followed by smaller shark species such as requiem sharks and the ancestors of today's cetaceans, dolphins and whales. Larger sharks such as sand tiger sharks were further up the food pyramid, and at the top were giant sharks like Araloselachus cuspidatus and the Otodus shark genus, which includes Megalodon. Results of the study showed that the levels of zinc found in the Megalodon couldn't be sharply differentiated from the lower levels of the pyramid, suggesting that the largest shark that ever lived was flexible enough to feed on both marine mammals and large fish from the top of the food pyramid as well as lower levels. Jeremy McCormack at the mass spectrometer, which is used to determine the zinc isotope ratio. This ratio provides information about the diet of Otodus megalodon. Photo: Uwe Dettmar for Goethe University Jeremy McCormack at the mass spectrometer, which is used to determine the zinc isotope ratio. This ratio provides information about the diet of Otodus megalodon. Photo: Uwe Dettmar for Goethe University Uwe Dettmar, Goethe University "Our study tends rather to draw a picture of megalodon as an ecologically versatile generalist," McCormack added. The shark's diet also greatly varied depending on its location and regional availability of prey. The teeth used for the study mostly came from 18-million-year-old fossil deposits in the German cities of Sigmaringen and Passau—and sharks in these locations showed different food habits. The creatures from Passau fed more on prey from lower levels of the food pyramid, probably due to lack of bigger fish in the area. McCormack said that the new method of determining tooth zinc isotope ratios has once proven to be a valuable instrument for paleoecological reconstructions. Kenshu Shimada, paleobiologist at DePaul University in Chicago, USA, and coauthor of the study added: "It gives us important insights into how the marine communities have changed over geologic time, but more importantly the fact that even 'supercarnivores' are not immune to extinction." Do you have a tip on a science story that Newsweek should be covering? Do you have a question about Megalodon? Let us know via science@
The Guardian
23-04-2025
- Politics
- The Guardian
A surprising number of Americans want climate action. But why aren't there more?
Over the last 12 months, the United States has endured a rash of disasters worsened by the climate crisis: devastating wildfires in southern California, a catastrophic hurricane in western North Carolina, and deadly heatwaves across the country. Americans increasingly believe global heating is a serious threat that will affect them personally – and 74% want to see more climate action. Yet while that sounds high, it is still lower than most other countries around the world. What explains this disparity? New insights into this question have emerged from recent research that examines attitudes toward the climate crisis across the world and in the US specifically. A report published by Nature Climate Change last year found 89% of the world's population wanted to see more climate action, and 69% even said they would be willing to contribute 1% of their personal income to the cause. But on all counts, the United States – the world's largest economy and its second largest carbon polluter – ranked among the lowest in terms of willingness to contribute, demand for action and belief that others would contribute. 'The climate debate in the US was always very specific in international comparison,' said Peter Andre, a behavioral economist at Safe and the Goethe University Frankfurt and a coauthor of the Nature report. He pointed to research that has found 'it was always more partisan, the media landscape is structured differently than in many European countries, and many [climate misinformation campaigns] also originated in the US.' Andre and his colleagues reviewed data from 130,000 people in 125 countries and found that respondents' willingness to contribute part of their income to the fight against climate change was highest in poorer countries. In Myanmar, which has a GDP of $1,233 per capita, 93% of respondents' said they would contribute; in the United States, where incomes are about 70 times higher, only 48% did. 'One very plausible hypothesis is that, of course, the extent that you are exposed to climate risk makes you more willing to act against it. The richer you are, the easier it is for you to adapt,' Andre said. 'The other story is resistance to change. Current economies are run on fossil fuels, so the bigger the economy, the more things need to change in order to become climate neutral.' The data, which was pulled from surveys conducted by Gallup in 2021 and 2022, showed respondents in France, Japan and Canada were about as willing as Americans to contribute financially to climate action but were more likely to demand political action. Danes, on the other hand, were about as likely as Americans to demand political action but much more willing to contribute income. 'We're kind of an outlier on the global scene,' said Jennifer Marlon, a research scientist and lecturer at Yale University. 'I think it's driven in large part by strong fossil fuel interests and the close associations they have with elected officials.' The oil and gas industry spent about $220m in campaign and political action committee donations in the 2024 US election, according to a recent Yale Climate Connections analysis. About 88% of donations went toward Republican candidates, including nearly $23m toward Donald Trump and groups supporting him. According to Marlon, Americans' 'strong sense that individuals can take care of everything' also hampered support for collective climate action. Marlon's most recent analysis of public attitudes toward climate change, published last month, found 63% of Americans said they were worried about climate change yet fewer than half (45%) thought they would be personally and significantly harmed by it. She said that even though a majority of Americans support climate action, that didn't necessarily translate into votes. 'It has not been the primary motivating factor. People are just prioritizing other issues – education, healthcare or government overreach,' she said. Carey Funk, a senior adviser with the Aspen Institute, pointed to the United States' deep political divisions over climate policy. 'Other places with a more ideological division over climate action tend to be in western Europe and in English-speaking countries, such as Canada, Australia,' she said. 'The [US's] two-party system makes the polarization over issues like this more pronounced.' Funk said distrust in traditional journalism was another important factor. Only about one-third of Americans say they trust mass media. In 2023, Funk conducted in-depth interviews with Americans who did not see climate change as a major threat, and she said many respondents expressed skepticism of legacy media. She also said messaging from climate groups does not always have its intended effects. 'The more the advocates are hyping up the problem, the more skeptical people feel they need to be,' she said. Peter Fisher, a professor of political sociology at the University of Oxford and an author of The Peoples' Climate Vote, a climate survey of 1.2 million people, said the Nature findings largely tracked with what he found: widespread support 'nearly across the board' for a rapid transition away from the burning of fossil fuels. He pointed to a few notable exceptions, including Russia, the US, Canada, Australia and, to a lesser extent, the UK. Like Funk, he attributed these exceptions, in part to 'partisan divisions on climate issues'. However, he stressed, even in these countries a majority of respondents favored a transition away from fossil fuels. 'There is concern about climate change and people want to see action,' he said. One thing respondents across the globe had in common? A tendency to underestimate their fellow citizens. In the United States, nearly half of respondents in the Nature study were willing to contribute some of their income to fighting climate change, but respondents believed only 33% of the rest of the country were willing to do so. Fisher and other experts said making people aware that they are in fact in the majority could help them put pressure on elected officials to act against climate change. 'Politicians often have much more political space than they think they do on climate change and other issues,' he said. 'And so I would say this, along with climate science, provides compelling reasons for actually acting on climate.' This story is part of the 89% Project, an initiative of the global journalism collaboration Covering Climate Now
Yahoo
04-04-2025
- Science
- Yahoo
Something Truly Scary Discovered at The Bottom of Belize's Great Blue Hole
An expedition to the bottom of the Great Blue Hole off the coast of Belize in Central America has returned with a cargo of worrying information. After studying a 30-meter (98-foot) sediment core extracted from the floor of the sinkhole, scientists discovered that tropical cyclones have increased in frequency over the last 5,700 years. This trend is not only going to continue – it's going to reach a fever pitch driven by a changing climate. "A total of 694 event layers were identified. They display a distinct regional trend of increasing storminess in the southwestern Caribbean, which follows an orbitally driven shift in the Intertropical Convergence Zone," writes a team led by geoscientist Dominik Schmitt of Goethe University Frankfurt in Germany. "A 21st-century extrapolation suggests an unprecedented increase in tropical cyclone frequency, attributable to the Industrial Age warming." The Great Blue Hole at Belize is a popular destination for scuba divers, popularized by oceanographer Jacques Cousteau more than 50 years ago. At a depth of 124 meters, it plunges into the surrounding seafloor, its upper reaches a haven for marine life seeking protection from the wild vagaries of ocean weather. There's another facet to this relative coziness; any sediment dumped within is likely to stay put. Layers of mineral deposited in sequence on the sinkhole floor serve as an excellent record of times past, recording major events like cyclones that churn up and dump new material into the Great Blue Hole. "Due to the unique environmental conditions – including oxygen-free bottom water and several stratified water layers – fine marine sediments could settle largely undisturbed in the Great Blue Hole," Schmitt explains. "Inside the sediment core, they look a bit like tree rings, with the annual layers alternating in color between gray-green and light green depending on organic content." The extraction of a core sample is a delicate procedure that involves drilling into the seafloor and carefully removing a long, vertical, cylindrical section. An analysis of that sediment involves identifying which layers were deposited by which processes. Violent events such as cyclones deposit layers with larger sediment grains than non-storm ocean processes, so it's a matter of carefully combing over the core and identifying those large-grained, differently-hued cyclone deposits. "The tempestites stand out from the fair-weather gray-green sediments in terms of grain size, composition, and color, which ranges from beige to white," Schmitt says. The Great Blue Hole of Belize started its life as a limestone cave underground, an origin alluded to by the huge stalactites that can still be found in its depths. It became a sinkhole during the last glacial period, when its roof collapsed, subsequently flooding the cavity with water and transforming it into the thriving marine ecosystem it is today. The team's work involved carefully studying a core that covered the most recent 5,700 years of that history. In that timespan, the researchers identified 694 "event layers" that they attributed to tropical cyclones. With this data in hand, they were then able to piece together how cyclone frequency has changed over time The core revealed a steady trend of increasing cyclone activity over the 5,700 years. "A key factor has been the southward shift of the equatorial low-pressure zone," Schmitt says. "Known as the Intertropical Convergence Zone, this zone influences the location of major storm formation areas in the Atlantic and determines how tropical storms and hurricanes move and where they make landfall in the Caribbean." But there were smaller-term fluctuations in cyclone frequency that, the researchers found, could be linked to warmer and cooler periods in Earth's climate timeline, with greater frequency occurring during warm periods. Based on these trends, we could be facing an unprecedented spike in tropical cyclone activity. There were nine cyclone events in the last 20 years alone; a frequency that is inconsistent with normal, natural climate fluctuations. "Our results suggest that some 45 tropical storms and hurricanes could pass over this region in our century alone," says biosedimentologist Eberhard Gischler of Goethe University Frankfurt. "This would far exceed the natural variability of the past millennia." The team's research has been published in Science Advances. 'Largest' Rare Earth Metals Deposit Discovered in Kazakhstan Oxygen Metabolism Emerged on Earth Before The Great Oxidation Event, Study Reveals Earth's Crust Is Dripping Under Midwest US, Scientists Discover
Yahoo
02-04-2025
- Science
- Yahoo
Scientists drilled into Belize's Great Blue Hole and discovered a worrying trend
When you buy through links on our articles, Future and its syndication partners may earn a commission. Tropical cyclones in the Caribbean are getting more frequent — and could increase significantly in the coming decades, evidence found buried deep within the Great Blue Hole suggests. Researchers took a sediment core from the Great Blue Hole sinkhole, situated about 50 miles (80 kilometers) off the coast of Belize, which revealed that tropical cyclones have increased in frequency over the past 5,700 years. The scientists described their findings in a study published March 14 in the journal Geology. "A key finding of our study is that the regional storm frequency has increased continuously since 5,700 years B.P. (before present)," study lead author Dominik Schmitt, a researcher at Goethe University Frankfurt's Biosedimentology Research Group, told Live Science. "Remarkably, the frequency of storm landfalls in the study area has been much higher in the last two decades than in the last six millennia — a clear indication of the influence of Modern Global Warming." Tropical cyclones are intense, rotating, low-pressure systems that form over warm ocean waters. They transfer heat from the ocean into the upper atmosphere. Tropical cyclones can be extremely destructive, producing strong winds, heavy rainfall and storm surges. To learn more about these storms over a long period of time, the researchers extracted the sediment core from the bottom of the 410-foot-deep (125 meters) Great Blue Hole — a massive underwater sinkhole that formed as sea levels rose during the last ice age, around 10,000 years ago. This sediment core, measuring 98 feet (30 m) long, is the longest continuous record of tropical storms in the area. By analyzing the layers of sediment in the core, the scientists could determine the number of tropical cyclones that had occurred over the past 5,700 years. Two layers of fair-weather sediment are usually laid down every year, enabling the researchers to count back the years like the rings of a tree and compare when storm-event sediment layers were deposited. The researchers found that tropical cyclones have been getting more frequent over the past 5,700 years, with a particular increase in frequency since we started burning fossil fuels during the Industrial Revolution. "Over the past six millennia, between four and sixteen tropical storms and hurricanes have passed over the Great Blue Hole every century," Schmitt said. In the past 20 years alone, however, the researchers found evidence of nine tropical storms passing over the same region. There appear to be two factors driving the rise in tropical cyclones, the researchers noted. Much of the frequency increases over the past few thousand years may be due to a southward migration of the Intertropical Convergence Zone (ITCZ). The ITCZ is a region near the equator where the trade winds of the Northern and Southern hemispheres come together, resulting in low atmospheric pressure, high humidity and frequent thunderstorms. Along the northern edge of the ITCZ is the Hurricane Main Development Region (MDR), where most tropical cyclones in the Atlantic form. The ITCZ usually moves northward in the summer and southward in the winter as a result of changing sea surface temperatures, but it has also been steadily moving southward over the past few thousand years. This southward migration of the ITCZ "has probably led to a southward displacement of the major Atlantic storm genesis region, and a shift of the main storm trajectories from formerly higher to now lower latitudes," Schmitt explained. Increases in global sea surface temperatures as a result of human-caused climate change are likely responsible for the recent spike in tropical storms, and will likely result in even more frequent tropical cyclones in the coming decades, according to the study. "The nine modern storm layers from the last 20 years indicate that extreme weather events in this region will become much more frequent in the 21st century," Schmitt said. The researchers predict that as many as 45 tropical storms and hurricanes could hit the Caribbean before the end of 2100. RELATED STORIES —Deepest blue hole in the world discovered, with hidden caves and tunnels believed to be inside —'More people are in harm's way': Tornadoes are shifting east of Tornado Alley, forecasters warn —Giant, near-perfect cloud ring appears in the middle of the Pacific Ocean — Earth from space "This high number is far in excess of what has been the case in the past 5,700 years," Schmitt said. "An explanation for this high storm frequency is not the natural variations in climate or solar radiation, but the progressive global warming during the Industrial Age, accompanied by fast rising sea-surface temperatures and stronger global La Niña events, which create optimal conditions for the development and rapid intensification of storms."
