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The Anthropocene epoch: scientists declare dawn of human-influenced age

The Anthropocene epoch: scientists declare dawn of human-influenced age | Amazing Science | Scoop.it

Humanity’s impact on the Earth is now so profound that a new geological epoch – the Anthropocene – needs to be declared, according to an official expert group who presented the recommendation to the International Geological Congress in Cape Town on Monday.

 

The new epoch should begin about 1950, the experts said, and was likely to be defined by the radioactive elements dispersed across the planet by nuclear bomb tests, although an array of other signals, including plastic pollution, soot from power stations, concrete, and even the bones left by the global proliferation of the domestic chicken were now under consideration.

 

The current epoch, the Holocene, is the 12,000 years of stable climate since the last ice age during which all human civilisation developed. But the striking acceleration since the mid-20th century of carbon dioxide emissions and sea level rise, the global mass extinction of species, and the transformation of land by deforestation and development mark the end of that slice of geological time, the experts argue.

 

The Earth is so profoundly changed that the Holocene must give way to the Anthropocene. “The significance of the Anthropocene is that it sets a different trajectory for the Earth system, of which we of course are part,” said Prof Jan Zalasiewicz, a geologist at the University of Leicester and chair of the Working Group on the Anthropocene (WGA), which started work in 2009.

 

“If our recommendation is accepted, the Anthropocene will have started just a little before I was born,” he said. “We have lived most of our lives in something called the Anthropocene and are just realising the scale and permanence of the change.”

 

Prof Colin Waters, principal geologist at the British Geological Survey and WGA secretary, said: “Being able to pinpoint an interval of time is saying something about how we have had an incredible impact on the environment of our planet. The concept of the Anthropocene manages to pull all these ideas of environmental change together.”

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Dinosaurs killed off by 'one-two punch' of climate change and asteroid strike

Dinosaurs killed off by 'one-two punch' of climate change and asteroid strike | Amazing Science | Scoop.it

The dinosaurs’ long reign was not ended swiftly but by torturous millennia of climate change before and after a giant asteroid slammed into Earth, scientists have said. The impact at Chicxulub in modern-day Mexico certainly contributed to the disappearance of the dinosaurs, but was by no means the sole cause, a team concluded in a study published in Nature Communications.

 

Ten of the 24 species which disappeared at one Antarctic island did so long before the comet or an asteroid hit the planet some 66m years ago. The other 14 disappeared in a second extinction wave that started with the impact contributing to the second-biggest mass extinction in history. Nearly half of life on Earth, including all non-avian dinosaurs, were wiped out.

 

The dinosaurs’ demise, according to US-based researchers in the new paper, was caused by two periods of global warming – the first sparked by monster volcanic eruptions in what is India today, and the second by the asteroid’s impact.

 

Both sets of calamities would have emitted ash and dust with short-term Sun-blocking and cooling effects, but also massive ejections of planet-heating greenhouse gases that would have caused “warming episodes” in the longer term.

 

“We find that the end-Cretaceous mass extinction was caused by a combination of the volcanism and asteroid impact, delivering a theoretical ‘one-two punch’,” said study co-author Sierra Petersen of the University of Michigan, using boxing terminology.

 

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Precambrian Protein Fragments Identified, Almost 2 Billion Years Old

Precambrian Protein Fragments Identified, Almost 2 Billion Years Old | Amazing Science | Scoop.it
They say it’s almost two billion (with a B) years old, yet it resembles modern counterparts.

 

The Gunflint Chert in Canada has long been a hot spot for microbe hunters. J. William Schopf identified microbial fossils in these rocks years ago. Only recently, however, have scientists been able to probe the structure of molecules within the fossils. Not all of the living material has been permineralized (that is, replaced by minerals such as silicates). Unbelievably, there are still traces of the original organic molecules present, as reported in Nature Communications by Alleon et al. “Molecular preservation of 1.88 Ga Gunflint organic microfossils as a function of temperature and mineralogy.”

 

The significant degradation that fossilized biomolecules may experience during burial makes it challenging to assess the biogenicity of organic microstructures in ancient rocks. Here we investigate the molecular signatures of 1.88 Ga Gunflint organic microfossils as a function of their diagenetic history. Synchrotron-based XANES data collected in situ on individual microfossils, at the submicrometre scale, are compared with data collected on modern microorganisms. Despite diagenetic temperatures of ~150–170 °C deduced from Raman data, the molecular signatures of some Gunflint organic microfossils have been exceptionally well preserved. Remarkably, amide groups derived from protein compounds can still be detected.

 

The scientists collected samples from about 7 locations. Using models of metamorphic temperatures during diagenesis (rock formation), they show that slightly higher temperatures in some regions erased the signature of protein compounds. Yet as they say, “remarkably” some protein compounds survived temperatures up to 338° F.

 

They repeatedly say that the spectra show exceptional preservation when compared to modern microbes:

Taking advantage of the unique capabilities of STXM-based XANESspectroscopy at the carbon and nitrogen K edges to perform in situ experiments at the submicrometre scale, the present study shows that, in addition to the fine-scale morphologies, the molecular biosignatures of some Gunflint organic microfossils have been exceptionally preserved. In fact, despite the 1.88-Gyr-long geological history that they experienced, Kakabeka Falls and Schreiber Beach organic microfossils exhibit C– and N-XANES spectra sharing strong similarities to those of modern cyanobacteria and modern micro-algae. Despite a higher content of aromatic compounds compared to modern microorganisms, these microfossils exhibit a quite high content of oxygen-based functional groups (carbonyl, phenolic, carboxylic and hydroxyl groups). In addition, these microfossils still contain amide functional groups(absorption feature at 288.2 eV), which were likely to be involved in the proteinaceous compounds synthetized by the once living organisms.


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YEC Geo's curator insight, June 22, 9:28 AM
The age range of preserved organic material grows ever longer.

From the article abstract: "Remarkably, amide groups derived from protein compounds can still be detected."

Original article here: http://www.nature.com/ncomms/2016/160617/ncomms11977/full/ncomms11977.html
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Complex life on Earth began a billion years earlier than previously thought, study argues

Complex life on Earth began a billion years earlier than previously thought, study argues | Amazing Science | Scoop.it

A claim by researchers that complex life on Earth may have evolved a billion years earlier than previously thought has immediately divided scientists in the field, with some hailing the evidence as rock-solid and others unconvinced.

The researchers, writing in the journal Nature Communications, said they had uncovered fossils showing that complex life on Earth began more than 1.5bn years ago.

After first emerging from the primordial soup, life remained primitive and single-celled for billions of years, but some of those cells eventually congregated like clones in a colony. Scientists took to calling the later part of this period the “boring billion” because evolution seemed to have stalled.

But at some point there was a leap – arguably second in importance only to the appearance of life itself – towards complex organisms with multiple cells.

This transition progressively gave rise to all the plants and animals that have ever existed.

Exactly when multi-celled “eukaryotes” – organisms in which differentiated cells each contain a membrane-bound nucleus with genetic material – showed up has inflamed scientific passions for many decades.

“Our discovery pushes back nearly one billion years the appearance of macroscopic, multi-cellular eukaryotes compared to previous research,” said Maoyan Zhu, a professor at the Nanjing Institute of Geology and Palaeontology.

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First-Ever 3D Atlas of Extinct Dodo Created

First-Ever 3D Atlas of Extinct Dodo Created | Amazing Science | Scoop.it
A full description has been made of the skeletal anatomy of a bird synonymous with the word extinction.

 

The atlas, now published in the Journal of Vertebrate Paleontology, is the first document to display the dodo skeleton with proportional accuracy, say its creators, a team of international scientists. The atlas also describes previously unknown dodo bones such as kneecaps, ankles, and wrists.

 

“Being able to examine the skeleton of a single, individual dodo, truly allows us to grasp what an actual dodo looked like and how it must have operated in its island environment,” said project co-contributor Leon Claessens, of the College of the Holy Cross’s biology department, in a statement.

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Chicxulub: How We Found the Dinosaur Doomsday Site

Chicxulub: How We Found the Dinosaur Doomsday Site | Amazing Science | Scoop.it

Looking back on nailing down the most important event in the past 100 million years, 25 years after discovering Chicxulub. 

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Many species now going extinct may vanish without a fossil trace

Many species now going extinct may vanish without a fossil trace | Amazing Science | Scoop.it

Scientists struggle to compare the magnitude of Earth’s ongoing sixth mass-extinction event with the five great die-offs of prehistory. A new study by three paleontologists shows that the species now perishing may vanish without a permanent trace – and earlier extinctions may be underestimated as well.

 

“Comparing the current biodiversity crisis, often called the ‘sixth extinction,’ with those of the geological past requires equivalent data,” says Roy Plotnick, professor of earth and environmental sciences at the University of Illinois at Chicago. He and two colleagues compared the “Red List” of endangered species with several ecological databases of living species and three paleontological databases of catalogued fossils.

 

They ran a statistical analysis to indicate which threatened species were most likely to disappear with no mark of their existence. The researchers were shocked to find that more than 85 percent of the mammal species at high risk of extinction lack a fossil record. Those at highest risk have about half the probability of being incorporated into the fossil record compared to those at lower risk. Animals least likely to be found as fossils are “the small, cute and fuzzy ones, like rodents and bats,” Plotnick said.

 

“Body size is an obvious factor — bigger things tend to leave a fossil record, as do things with larger geographical ranges.” Viewed from the perspective of the fossil record alone, the magnitude of the current mammal die-off thus appears markedly reduced. The picture may be even more distorted for other land-dwelling vertebrates: only 3 percent of today’s threatened bird species and 1.6 percent of threatened reptile species have a known fossil record.

 

Comparing the scale of the current extinction episode, which is based primarily on terrestrial vertebrates, to earlier extinctions that are mostly calculated from the fossil record of hard-shelled marine invertebrates, is particularly problematic, Plotnick said, although ancient extinctions may also be underestimated by contemporary paleontologists. Nevertheless, fossils will provide the only reliable record of life on Earth for posterity. “There are species going extinct today that have never been described,” Plotnick said. “Others are going extinct that are known only because someone wrote it down.” All such species would thus be unknown in the far future, he said, if the written historical record is lost — as it might well be. - See more at: http://news.uic.edu/many-species-now-going-extinct-may-vanish-without-a-fossil-trace#sthash.48da4XXU.dpuf

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New Tyrannosaur species shows how T. Rex developed brains before brawn

New Tyrannosaur species shows how T. Rex developed brains before brawn | Amazing Science | Scoop.it

How did the Tyrannosaurus rex become one of the fiercest dinosaurs the planet has ever seen? By developing keen senses prior to the growth spurt that allowed it to grow to be as much as 13 feet tall and weigh close to seven metric tons, according to a new study.

 

According to lead researcher Dr. Steve Brusatte from the University of Edinburgh’s School of GeoSciences and his colleagues, the new remains of a horse-sized dinosaur recently unearthed in Uzbekistan shed new light on how and when tyrannosaurs became such fearsome predators.

 

As they explained in Monday’s edition of the Proceedings of the National Academy of Sciences, the fossils belonged to a newly identified species, Timurlengia euotica, that lived approximately 90 million years ago and which had much smaller bodies than T. rex and other tyrannosaurs.

 

Its discovery also fills a 20-million-year-gap in the tyrannosaur fossil record, the authors noted, showing how these horse-sized, 250 kilogram, long-legged, sharp-toothed, fast-running dinosaurs went on to evolve into the massive, intelligent carnivores that dominated the Earth about 66 million years ago. The secret, they said, was that tyrannosaurs developed brains before brawn.

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Dodos Might Have Been Quite Intelligent

Dodos Might Have Been Quite Intelligent | Amazing Science | Scoop.it

New research suggests that the dodo, an extinct bird whose name has entered popular culture as a symbol of stupidity, was actually fairly smart. The work, published today in the Zoological Journal of the Linnean Society, finds that the overall size of the dodo’s brain in relation to its body size was on par with its closest living relatives: pigeons—birds whose ability to be trained implies a moderate level of intelligence. The researchers also discovered that the dodo had an enlarged olfactory bulb—the part of the brain responsible for smelling—an uncharacteristic trait for birds, which usually concentrate their brainpower into eyesight.


The dodo (Raphus cucullatus) was a large, flightless bird that lived on the island of Mauritius in the Indian Ocean. They were last seen in 1662. “When the island was discovered in the late 1500s, the dodos living there had no fear of humans and they were herded onto boats and used as fresh meat for sailors,” said Eugenia Gold, the lead author of the paper, a research associate and recent graduate of the American Museum of Natural History’s Richard Gilder Graduate School, and an instructor in the Department of Anatomical Sciences at Stony Brook University. “Because of that behavior and invasive species that were introduced to the island, they disappeared in less than 100 years after humans arrived. Today, they are almost exclusively known for becoming extinct, and I think that’s why we’ve given them this reputation of being dumb.”


Even though the birds have become an example of oddity, obsolescence, stupidity, and extinction, and have been featured in popular stories ranging from Alice in Wonderland to Ice Age, most aspects of the dodo’s biology are still unknown. This is partly because dodo specimens are extremely rare, having disappeared during the nascent stage of natural history collections.


To examine the brain of the dodo, Gold tracked down a well-preserved skull from the collections of the Natural History Museum, London, and imaged it there with high-resolution computed tomography (CT) scanning. In the American Museum of Natural History’s Microscopy and Imaging Facility, she also CT-scanned the skulls of seven species of pigeons—ranging from the common pigeon found on city streets, Columba livia, to more exotic varieties. Out of these scans, Gold built virtual brain endocasts to determine the overall brain size as well as the size of various structures. Gold’s colleagues at the Natural History Museum of Denmark and National Museum of Scotland sent her the endocast for the dodo’s closest relative, the extinct island-dwelling bird Rodrigues solitaire (Pezophaps solitaria).


When comparing the size of the birds’ brains to their body sizes, Gold and collaborators found that the dodo was “right on the line.”


“It’s not impressively large or impressively small—it’s exactly the size you would predict it to be for its body size,” Gold said. “So if you take brain size as a proxy for intelligence, dodos probably had a similar intelligence level to pigeons. Of course, there’s more to intelligence than just overall brain size, but this gives us a basic measure.”


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Scientists unearth bacteria from stomach of 5,300-year-old iceman

Scientists unearth bacteria from stomach of 5,300-year-old iceman | Amazing Science | Scoop.it

n 1991, a German couple hiking in the Alps came across the body of a middle-aged man lying face down in a snowfield. It took days for a recovery team to hack him out of the ice and haul him by helicopter and truck to a lab in Austria. There, scientists determined the man had died 5,300 years ago.


Ötzi, as the man was nicknamed (after the nearby Ötztal Valley), has kept scientists very busy for the past 24 years. They’ve even built an entire research center — the Institute for Mummies and the Iceman in Bolzano, Italy — to house Ötzi and study him. They’ve slowly extracted one clue after another about how Ötzi died and, more importantly, how he lived.


But Ötzi still has much left to tell us. On Thursday, researchers reported in the journal Science that they have reconstructed the entire genome of a species of bacteria that lived in his stomach. Now Ötzi may be able to tell us not just about ancient humans. He can tell us about ancient microbiomes, too.


Part of the reason Ötzi is so revealing is the way he died. He was probably killed by an arrow to the back. His body was then quickly buried in snow and then freeze-dried. As a result, he wasn’t torn apart by scavengers or decomposed by microbes.


When researchers began to study Ötzi, they focused their attention on his anatomy, using X-rays to probe his bones, muscles, and organs. But in recent years they’ve also begun using DNA-sequencing technology to search for genetic material.


In 2012, researchers published Ötzi’s entire genome, which showed he was closely related to people living today in Corsica and Sardinia. He had genes for type O blood and brown eyes; he was probably lactose intolerant and ran an increased risk of coronary heart disease.


While the geneticists were piecing together Ötzi’s genes, the anatomists made a surprising discovery: his stomach. It had migrated up into his rib cage, where it had been hidden from scientific view for 16 years.


Whenever scientists find DNA in ancient remains, they have to take extra steps to rule out the possibility that the DNA actually comes from some modern organism that contaminated their equipment. In their new study, Maixner and his colleagues only found H. pylori DNA in the stomach, and not in nearby tissue. The DNA was also damaged in a distinctive way that allowed them only to see DNA that has been lying around for thousands of years.


“These two facts led us to the assumption that we were on the right track,” said Maixner. The scientists then pieced together overlapping DNA sequences of Ötzi’s H. pylori. Eventually they could build up almost the entire genome of the microbe. Before the new study, H. pylori expert Martin Blaser, the director of the Human Microbiome Program at New York University Langone Medical Center, had been skeptical that anyone would ever find DNA from ancient H. pylori. “Now we have a solid piece of data,” he said.

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Asteroid impact helped create the birds we know today

Asteroid impact helped create the birds we know today | Amazing Science | Scoop.it

Modern birds originated in Southern Hemisphere about 95 million years ago.


Modern birds, a group called Neornithes are the most diverse and widespread vertebrates on Earth today. Previous studies that used only information from genetic analyses of current species have suggested that birds arose anywhere from 72 million to 170 million years ago. But the new study, which includes anatomical data extinct species preserved in the fossil record, narrows that window considerably, says Joel Cracraft, an ornithologist at the American Museum of Natural History in New York City.


He and museum colleague Santiago Claramunt, also an ornithologist, didn’t include well-known ancient birds such as Archaeopteryx and Confuciusornis, which belonged to lineages that eventually died out. They only looked at species that belonged to the three major groups of birds alive today: Palaeognathae (ostriches and their close relatives), Galloanseres (waterfowl, pheasants, and their close kin), and Neoaves (all other birds).


The team’s genetic information came from analyses of two particular genes from 230 species representing all major subgroups of modern birds. (Mutations in those genes, which are related to basic biochemical processes that take place in all cells, helped the researchers estimate when those groups arose or diverged from their closest relatives, Cracraft says.) Anatomical data from 130 extinct species that had once lived worldwide helped the team figure out when and where those groups originated, as well as how quickly they evolved.


The results suggest that the last common ancestor of all modern birds—in other words, the species at the base of the evolutionary family tree that includes all living bird species—lived in West Gondwana, a landmass that included what are now fragments of South America and large portions of Antarctica, about 95 million years ago. What’s more, all three major groups—Palaeognathae, Galloanseres, and Neoaves—had already arisen by the time the dino-killing asteroid smacked our planet 66 million years ago, the researchers report online today inScience Advances. So although the resulting die-offs may not have triggered the original diversification of birds, by eliminating many ecological competitors, the extinction provided opportunities for survivors to diversify and spread, Cracraft says.


In eras since the asteroid impact, changes in global climate significantly affected how quickly new species evolved, the researchers found. When global climate cooled, areas experiencing what are today considered tropical conditions shrank back toward the equator, and the net rate of species appearance (the number of new species that evolved minus the number that went extinct) increased. When global warmth returned, those newly minted species could then spread worldwide—as long as they didn’t run into gaps between continents too big for them to fly across. Birds stuck on landmasses that had drifted into isolation due to the long-term movement of Earth's tectonic plates, such as Australia and New Zealand, were consigned to evolve in isolation.

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Globally unique double crater identified in Sweden: Impact 460 million years ago

Globally unique double crater identified in Sweden: Impact 460 million years ago | Amazing Science | Scoop.it

Researchers at the University of Gothenburg have found traces of two enormous meteorite impacts in the Swedish county of Jämtland, a twin strike that occurred around 460 million years ago.

The researchers have discovered two craters in Jämtland. One is enormous, while the other is a tenth of the size of the first. "The two meteorite impacts occurred at the same time, 458 million years ago, and formed these two craters," says Erik Sturkell, Professor of Geophysics at the University of Gothenburg.

Erik Sturkell and his research colleagues found one of the craters 20 kilometres south of Östersund in Brunsflo. This is an enormous crater, with a diameter of 7.5 kilometers. The smaller crater is located 16 kilometers from there, and has a diameter of 700 meters.


The two meteorite impacts 458 million years ago were not the only ones to strike Earth at this time. "Around 470 million years ago, two large asteroids collided in the asteroid belt between Mars and Jupiter, and many fragments were thrown off in new orbits. Many of these crashed on Earth, such as these two in Jämtland," says Erik Sturkell.


Jämtland was under the sea at the time, with a water depth of 500 meters at the points where two meteorites simultaneously stuck. Double impacts like this are very unusual. This is the first double impact on Earth that has been conclusively proved. "Information from drilling operations demonstrates that identical sequences are present in the two craters, and the sediment above the impact sequences is of the same age. In other words, these are simultaneous impacts," says Erik Sturkell. The water was forced away during the impact, and for a hundred seconds these enormous pits were completely dry.


"The water then rushed back in, bringing with it fragments from the meteorites mixed with material that had been ejected during the explosion and with the gigantic wave that tore away parts of the sea bed," says Erik Sturkell.

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Mining ancient ores for clues to early life on Earth

Mining ancient ores for clues to early life on Earth | Amazing Science | Scoop.it

An analysis of sulfide ore from a Canadian mine suggests microbes were active in ocean water 2.7 billion years ago.


Researchers examined sulfide ore deposits from one of the world’s richest base-metal mines—the Kidd Creek copper-zinc mine in Timmins, Ontario. The work confirms that oxygen levels were extremely low on Earth 2.7 billion years ago, but also shows that microbes were actively feeding on sulfate in the ocean and influencing seawater chemistry during that geological time period.


The research, reported by a team of Canadian and US scientists in Nature Geoscience, provides new insight into how ancient metal-ore deposits can be used to better understand the chemistry of the ancient oceans—and the early evolution of life. Sulfate is the second most abundant dissolved ion in the oceans today. It comes from the “rusting” of rocks by atmospheric oxygen, which creates sulfate through chemical reactions with pyrite, the iron sulfide material known as “fool’s gold.”


The researchers—led by PhD student John Jamieson of the University of Ottawa and Boswell Wing, an associate professor at McGill University—measured the “weight” of sulfur in samples of massive sulfide ore from the Kidd Creek mine using a highly sensitive instrument known as a mass spectrometer. The weight is determined by the different amounts of isotopes of sulfur in a sample, and the abundance of different isotopes indicates how much seawater sulfate was incorporated into the massive sulfide ore that formed at the bottom of ancient oceans.


That ancient ore is now found on the Earth’s surface, and is particularly common in the Canadian shield. The scientists found that much less sulfate was incorporated into the 2.7 billion-year-old ore at Kidd Creek than is incorporated into similar ore forming at the bottom of oceans today. From these measurements, the researchers were able to model how much sulfate must have been present in the ancient seawater.


Their conclusion: sulfate levels were about 350 times lower than in today’s ocean. Though they were extremely low, sulfate levels in the ancient ocean still supported an active global population of microbes that use sulfate to gain energy from organic carbon.


“The sulfide ore deposits that we looked at are widespread on Earth, with Canada and Quebec holding the majority of them,” says Wing. “We now have a tool for probing when and where these microbes actually came into global prominence.”


“Deep within a copper-zinc mine in northern Ontario that was once a volcanically active ancient seafloor may not be the most intuitive place one would think to look for clues into the conditions in which the earliest microbes thrived over 2.7 billion years ago,” Jamieson adds. “However, our increasing understanding of these ancient environments and our abilities to analyze samples to a very high precision has opened the door to further our understanding of the conditions under which life evolved.”

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Woolly mammoths' ultimate demise blamed on freshwater shortage

Woolly mammoths' ultimate demise blamed on freshwater shortage | Amazing Science | Scoop.it

Writing in the Proceedings of the National Academy of Sciences, the scientists reveal how they turned to sediment cores taken from a lake on St Paul Island to determine what finished off the mammoths, and when.

 

To pinpoint when the mammoths died out on the island, the team examined traces of ancient DNA found within sediment cores that had been collected and radiocarbon dated. “When the mammoths lived along the lake they probably waded into it, they probably defecated in it, urinated it in, bathed in it, so their DNA got into the lake water and settled to the bottom ,” said Russell Graham, the co-author of the study and professor of geosciences at Pennsylvania State University.

 

By extracting this sedimentary ancient DNA, and looking at where in the core it was present, the researchers discovered that mammoths seem to have to disappeared around 5,600 years ago. The conclusion was backed up by the analysis of fungal spores from within the core, which are thought to have grown in the mammoths’ dung. A new set of mammoth remains added further weight to the theory, with radiocarbon dating putting the youngest of the remains at 5,530 years ago.

 

To unravel the cause of the mammoths’ demise, researchers studied other markers within the sediment core, including the type of microorganisms and creatures that once lived in the water and which provide clues about the conditions within the lake. The team also looked at the ratio of different forms of oxygen over time - an indicator of the rate of evaporation of the water. Their findings reveal that between 7,850 and 5,600 years ago the lake became saltier, shallower and more turbid.

 

With rising sea levels shrinking the size of the island, and lakes becoming shallower, the mammoths would have been forced to rely on fewer water supplies, said Graham, adding that the animals themselves could have made a bad situation worse. “They started congregating around the two probably remaining water holes and when modern elephants do that they destroy the vegetation and it causes increased erosion and infilling of lakes - and that was happening as well, you can see that through the sediment,” he said.

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Termites figured out farming 25 million years before people did

Termites figured out farming 25 million years before people did | Amazing Science | Scoop.it

Scientists discovered an ancient fungus garden grown by termites millions of years ago.

 

The fossil structures bore every hallmark of a prehistoric farm: Crops were arranged according to an intricate, complex plan. Material for harvesting littered the ground. Analysis revealed that the crop was a species that only grows when cultivated.

This was agriculture — but underground and on a micro scale. At 25 million years old, it was also far more ancient than anything constructed by humans; Homo sapiens didn't even exist yet.

Instead, the farmers who tilled these ancient plots were termites. And their harvest was fungus. The fossilized termite gardens, uncovered from exposed cliff sides in the Rukwa Rift Basin of southwestern Tanzania, are the oldest physical evidence of farming on Earth, scientists report in the journal PLOS One this week.

 

"It captures a record of the evolutionary coupling of termites and fungus ... and allows us to trace back the antiquity of this symbiotic relationship," lead author Eric Roberts, a geologist at James Cook University in Australia, wrote in an email. "The new fossils help us to calibrate our evolutionary clocks and use them to better understand when this symbiosis first developed, which we now think was probably around 31 million years ago."

 

Across Africa, the massive, edible "termite mushrooms" grown by these tiny insects are famous. But European scientists didn't realize the significance of what was happening inside termite colonies until the mid-20th century. When researchers dissected towering termite mounds, which contain dozens of interlocking chambers and can grow taller than a person, they saw that the insects weren't just eating the fungus that grew alongside them — they were cultivating it.


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Strange sea-dwelling reptile fossil hints at rapid evolution after mass extinction

Strange sea-dwelling reptile fossil hints at rapid evolution after mass extinction | Amazing Science | Scoop.it

Two hundred and fifty million years ago, life on earth was in a tail-spin—climate change, volcanic eruptions, and rising sea levels contributed to a mass extinction that makes the death of the dinosaurs look like child's play.

 

In a paper published in Scientific Reports, paleontologists describe a new marine reptile, Sclerocormus parviceps, an ichthyosauriform that's breaking all the rules about what ichthyosaurs are like.

 

Ichthyosaurs were a massive group of marine reptiles that lived around the time of the earliest dinosaurs. Most of them looked a little bit like today's dolphins—streamlined bodies, long beak-like snouts, and powerful tail fins. But the new species is something of a black sheep. It has a short snout (its species name even means "small skull"), and instead of a tail with triangular flukes (think of a fish's tail-fins), it had a long, whip-like tail without big fins at the end. And while many ichthyosaurs had conical teeth for catching prey, Sclerocormus was toothless and instead seems to have used its short snout to create pressure and suck up food like a syringe. In short, it's really different from most of its relatives, and that tells scientists something important about evolution.

 

"Sclerocormus tells us that ichthyosauriforms evolved and diversified rapidly at the end of the Lower Triassic period," explains Olivier Rieppel, The Field Museum's Rowe Family Curator of Evolutionary Biology. "We don't have many marine reptile fossils from this period, so this specimen is important because it suggests that there's diversity that hasn't been uncovered yet."

 

The way this new species evolved into such a different form so quickly sheds light on how evolution actually works. "Darwin's model of evolution consists of small, gradual changes over a long period of time, and that's not quite what we're seeing here. These ichthyosauriforms seem to have evolved very quickly, in short bursts of lots of change, in leaps and bounds," says Rieppel.

 

Animals like Sclerocormus that lived just after a mass extinction also reveal how life responds to huge environmental pressures. "We're in a mass extinction right now, not one caused by volcanoes or meteorites, but by humans," explains Rieppel. "So while the extinction 250 million years ago won't tell us how to solve what's going on today, it does bear on the evolutionary theory at work. How do we understand the recovery and rebuilding of a food chain, of an ecosystem? How does that get fixed, and what comes first?"

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Geologists to drill into heart of dinosaur-killing impact

Geologists to drill into heart of dinosaur-killing impact | Amazing Science | Scoop.it
Quest aims to uncover secrets of big craters across the Solar System.

 

Geophysicists are returning to Earth’s most famous cosmic bullseye. Around 7 April, from a drill-ship off the coast of Yucatán, Mexico, they will start to penetrate the 200-kilometer-wide Chicxulub crater, which formed 66 million years ago when an enormous asteroid smashed into the planet. The aftermath of the impact obliterated most life on Earth, including the dinosaurs.

 

The expedition is the first to directly probe one of Chicxulub’s most striking features — its ‘peak ring’, a circle of mountains that rises within the crater floor. Scientists have yet to fully explain how peak rings form, even though they are common in big impact craters across the Solar System.

 

At Chicxulub, researchers will look for evidence to explain how a 14-kilometre-wide asteroid could have punched a hole that pushed rocks from the surface down some 20–30 kilometres. Flowing like liquid, the rocks then rebounded towards the sky — reaching as far as 10 kilometres above the original ground level — and finally splattered down to form a peak ring.

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A fossilised skull has revealed when the last 'Siberian unicorn' lived on Earth

A fossilised skull has revealed when the last 'Siberian unicorn' lived on Earth | Amazing Science | Scoop.it

For decades, scientists have estimated that the Siberian unicorn - a long-extinct species of mammal that looked more like a rhino than a horse - died out some 350,000 years ago, but a beautifully preserved skull found in Kazakhstan has completely overturned that assumption. Turns out, these incredible creatures were still around as recently as 29,000 years ago.  

 

Before we talk about the latest discovery, yes, there was a very real 'unicorn' that roamed Earth tens of thousands of years ago, but it was nothing like the one found in your favourite children’s book. (Sorry - it’s a bummer for us, too.) The real unicorn, Elasmotherium sibiricum, was shaggy and huge and looked just like a modern rhino, only it carried the most almighty horn on its forehead.

 

According to early descriptions, the Siberian unicorn stood at roughly 2 metres tall, was 4.5 metres long, and weighed about 4 tonnes. That’s closer to woolly mammoth-sized than horse-sized. Despite its very impressive stature, the unicorn probably was a grazer that ate mostly grass. So, if you want a correct image in your head, think of a fuzzy rhinoceros with one long, slender horn protruding from its face instead of a short, stubby one like today’s rhinos. 

 

The newly found skull, which was remarkably well-preserved, was found in the Pavlodar region of Kazakhstan. Researchers from Tomsk State University were able to date it to around 29,000 years ago via radiocarbon dating techniques. Based on the size and condition of the skull, it was likely a very old male, they suggest, but how it actually died remains unknown. 

 

The question on researchers' minds is how this unicorn lasted so much longer than those that died out hundreds of thousands of years earlier. "Most likely, the south of Western Siberia was a refúgium, where this rhino persevered the longest in comparison with the rest of its range," said one of the team, Andrey Shpanski. "There is another possibility that it could migrate and dwell for a while in the more southern areas."

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Earth had oxygen 800 million years earlier than thought

Earth had oxygen 800 million years earlier than thought | Amazing Science | Scoop.it

Until recently, scientists thought that oxygen first became a part of our atmosphere 2.2 billion years ago. But a new study pushes this further back in time, to about 3.8 billion years ago.

 

"I was quite shocked when I first saw the results,” says lead-author Robert Frei, who works at the Department of Earth Science and Nature Management at the University of Copenhagen, Denmark.

 

“This strikes into a very sensitive part of science, in which there is relatively little evidence, and yet the entire scientific community don’t believe that there was oxygen at this time. I’ve struggled against many critical peers and it’s taken me over a year to get the article published,” says Frei, adding that he feels confident about the results.

 

The conclusions are important and should improve our understanding of Earth’s history, says postdoc Emma Hammarlund from The University of Southern Denmark, who was not involved in the new study.

 

“The picture is not made any simpler perhaps, but the truth is rarely black and white. It’s a carefully executed study and argument,” she says.

 

The new results are published in the journal Scientific Reports.


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Solving the mystery of the Tully Monster

Solving the mystery of the Tully Monster | Amazing Science | Scoop.it

The Tully Monster, an oddly configured sea creature with teeth at the end of a narrow, trunk-like extension of its head and eyes that perch on either side of a long, rigid bar, has finally been identified.

 

A Yale-led team of paleontologists has determined that the 300-million-year-old animal — which grew to only a foot long — was a vertebrate, with gills and a stiffened rod (or notochord) that supported its body. It is part of the same lineage as the modern lamprey. “I was first intrigued by the mystery of the Tully Monster. With all of the exceptional fossils, we had a very clear picture of what it looked like, but no clear picture of what it was,” said Victoria McCoy, lead author of a new study in the journal Nature. McCoy conducted her research as a Yale graduate student and is now at the University of Leicester.

 

For decades, the Tully Monster has been one of the great fossil enigmas: It was discovered in 1958, first described scientifically in 1966, yet never definitively identified even to the level of phylum (that is, to one of the major groups of animals). Officially known as Tullimonstrum gregarium, it is named after Francis Tully, the amateur fossil hunter who came across it in coal mining pits in northeastern Illinois.

 

Thousands of Tully Monsters eventually were found at the site, embedded in concretions — masses of hard rock that formed around the Tully Monsters as they fossilized. Tully donated many of his specimens to the Field Museum of Natural History, which collaborated on the Nature study along with Argonne National Laboratory and the American Museum of Natural History.

 

The Tully Monster has taken on celebrity status in Illinois. It became the state fossil in 1989, and more recently, U-Haul trucks and trailers in Illinois began featuring an image of a Tully Monster. “Basically, nobody knew what it was,” said Derek Briggs, Yale’s G. Evelyn Hutchinson Professor of Geology and Geophysics, curator of invertebrate paleontology at the Yale Peabody Museum of Natural History, and co-author of the study. “The fossils are not easy to interpret, and they vary quite a bit. Some people thought it might be this bizarre, swimming mollusk. We decided to throw every possible analytical technique at it.”

 

Using the Field Museum’s collection of 2,000 Tully Monster specimens, the team analyzed the morphology and preservation of various features of the animal. Powerful, new analytical techniques also were brought to bear, such as synchrotron elemental mapping, which illuminates an animal’s physical features by mapping the chemistry within a fossil.

 

The researchers concluded that the Tully Monster had gills and a notochord, which functioned as a rudimentary spinal cord. Neither feature had been identified in the animal previously.

“It’s so different from its modern relatives that we don’t know much about how it lived,” McCoy said. “It has big eyes and lots of teeth, so it was probably a predator.”

 

Some key questions about Tully Monsters still remain unanswered, however. No one knows when the animal first appeared on Earth or when it went extinct. Its existence in the fossil record is confined to the Illinois mining site, dating back 300 million years.

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The oldest known land-dweller is a type of fungus

The oldest known land-dweller is a type of fungus | Amazing Science | Scoop.it

The earliest example of an organism living on land – an early type of fungus – has been identified. The organism, from 440 million years ago, likely kick-started the process of rot and soil formation, which encouraged the later growth and diversification of life on land.

A fossil dating from 440 million years ago is not only the oldest example of a fossilised fungus, but is also the oldest fossil of any land-dwelling organism yet found. The organism, and others like it, played a key role in laying the groundwork for more complex plants, and later animals, to exist on land by kick-starting the process of rot and soil formation, which is vital to all life on land.

This early pioneer, known as Tortotubus, displays a structure similar to one found in some modern fungi, which likely enabled it to store and transport nutrients through the process of decomposition. Although it cannot be said to be the first organism to have lived on land, it is the oldest fossil of a terrestrial organism yet found. The results are published in the Botanical Journal of the Linnean Society.

“During the period when this organism existed, life was almost entirely restricted to the oceans: nothing more complex than simple mossy and lichen-like plants had yet evolved on the land,” said the paper’s author Dr Martin Smith, who conducted the work while at the University of Cambridge’s Department of Earth Sciences, and is now based at Durham University. “But before there could be flowering plants or trees, or the animals that depend on them, the processes of rot and soil formation needed to be established.”

Working with a range of tiny microfossils from Sweden and Scotland, each shorter than a human hair is wide, Smith attempted to reconstruct the method of growth for two different types of fossils that were first identified in the 1980s. These fossils had once been thought to represent parts of two different organisms, but by identifying other fossils with ‘in-between’ forms, Smith was able to show that the fossils actually represented parts of a single organism at different stages of growth. By reconstructing how the organism grew, he was able to show that the fossils represent mycelium – the root-like filaments that fungi use to extract nutrients from soil.

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Multiple Cosmic Impacts 790,000 Years Ago With Global Consequences

Multiple Cosmic Impacts 790,000 Years Ago With Global Consequences | Amazing Science | Scoop.it
Approximately 790,000 years ago there were multiple cosmic impacts on earth with global consequences. Geoscientists from Heidelberg University reached this conclusion after dating so-called tektites from various parts of the world. The research group under the direction of Prof. Dr. Mario Trieloff studied several of such rock glasses, which originated during impacts of asteroids or comets. The Heidelberg scientists employed a dating method based on naturally occurring isotopes that allowed them to date the tektites more accurately than ever. Their studies show that the samples from Asia, Australia, Canada and Central America are virtually identical in age, although in some cases their chemistry differs markedly. This points to separate impacts that must have occurred around the same time. The results of their research funded by the Klaus Tschira Foundation were published in the journal “Geochimica et Cosmochimica Acta”.

The research group at the Institute of Earth Sciences and the Klaus Tschira Laboratory for Cosmochemistry uses isotope measurements to determine the age of craters caused by the impact of extraterrestrial rocks. “That's how we know when, where and how often projectiles struck the earth, and how big they were,” says Mario Trieloff. There have long been signs that a major event of this type took place on earth about a million years ago, according to Prof. Trieloff. This is evidenced by tektites, so-called rock glasses that arise during impact, whereby terrestrial material melts, is hurled up to several hundred kilometres and then hardens into glass.

“We have known about such tektites for some time from the Australasian region,” explains Dr. Winfried Schwarz, the study's primary author. These rock glasses form a strewn field that stretches from Indochina to the southernmost tip of Australia. Smaller tektites, known as microtektites, were also discovered in deep-sea drill cores off the coast of Madagascar and in the Antarctic. The rock glasses had been strewn over 10,000 kilometres, with some of them even leaving the earth's atmosphere. Using the 40Ar-39Ar dating method, which analyses the decay of the naturally occurring 40K isotope, the Heidelberg researchers succeeded in dating these tektites more accurately than ever before.

“Our data analysis indicates that there must have been a cosmic impact about 793,000 years ago, give or take 8,000 years,” explains Winfried Schwarz. The Heidelberg scientists also studied samples from Canada and Central America. The Canadian rock glasses had the same chemical composition and age as the Australasian tektites and could have covered similar “flight routes” as objects found in southern Australia or the Antarctic. Other finds must first confirm whether the recovery sites are really where the tektites originally landed or whether they for example were carried there by people, according to Dr. Schwarz.

The rock glasses from Central America are also tektites – the first specimens were found at Mayan sites of worship. In the meantime, hundreds of other finds have been made in Central America. “These tektites are clearly different in their chemical composition, and their geographical distribution also shows that they come from separate impacts,” explains Dr. Schwarz. “Surprisingly our age estimates prove that they originated 777,000 years ago with a deviation of 16,000 years. Within the error margin, this matches the age of the Australasian tektites.”
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Mammal diversity exploded immediately after dinosaur extinction

Mammal diversity exploded immediately after dinosaur extinction | Amazing Science | Scoop.it
The diversity of mammals on Earth exploded straight after the dinosaur extinction event, according to UCL researchers. New analysis of the fossil record shows that placental mammals, the group that today includes nearly 5,000 species including humans, became more varied in anatomy during the Paleocene epoch -- the 10 million years immediately following the event.


Senior author, Dr Anjali Goswami (UCL Genetics, Evolution & Environment), said: "When dinosaurs went extinct, a lot of competitors and predators of mammals disappeared, meaning that a great deal of the pressure limiting what mammals could do ecologically was removed. They clearly took advantage of that opportunity, as we can see by their rapid increases in body size and ecological diversity. Mammals evolved a greater variety of forms in the first few million years after the dinosaurs went extinct than in the previous 160 million years of mammal evolution under the rule of dinosaurs."


The Natural Environment Research Council-funded research, published today in the Biological Journal of the Linnean Society, studied the early evolution of placental mammals, the group including elephants, sloths, cats, dolphins and humans. The scientists gained a deeper understanding of how the diversity of the mammals that roamed the Earth before and after the dinosaur extinction changed as a result of that event.


Placental mammal fossils from this period have been previously overlooked as they were hard to place in the mammal tree of life because they lack many features that help to classify the living groups of placental mammals. Through recent work by the same team at UCL, this issue was resolved by creating a new tree of life for placental mammals, including these early forms, which was described in a study published in Biological Reviews yesterday.


First author of both papers, Dr Thomas Halliday (UCL Earth Sciences and Genetics, Evolution & Environment), said: "The mass extinction that wiped out the dinosaurs 66 million years ago is traditionally acknowledged as the start of the 'Age of Mammals' because several types of mammal appear for the first time immediately afterwards.


"Many recent studies suggest that little changed in mammal evolution during the Paleocene but these analyses don't include fossils from that time. When we look at the mammals that were present, we find a burst of evolution into new forms, followed by specialisation that finally resulted in the groups of mammals we see today. The earliest placental mammal fossils appear only a few hundred thousand years after the mass extinction, suggesting the event played a key role in diversification of the mammal group to which we belong."


The team studied the bones and teeth of 904 placental fossils to measure the anatomical differences between species. This information was used to build an updated tree of life containing 177 species within Eutheria (the group of mammals including all species more closely related to us than to kangaroos) including 94 from the Paleocene - making it the tree with the largest representation from Paleocene mammals to date. The new tree was analysed in time sections from 140 million years ago to present day, revealing the change in the variety of species.

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Scientists find link between comet and asteroid showers & mass extinctions

Scientists find link between comet and asteroid showers & mass extinctions | Amazing Science | Scoop.it

Mass extinctions occurring over the past 260 million years were likely caused by comet and asteroid showers, scientists conclude in a new study published in Monthly Notices of the Royal Astronomical Society.

For more than 30 years, scientists have argued about a controversial hypothesis relating to periodic mass extinctions and impact craters - caused by comet and asteroid showers - on Earth.


In their MNRAS paper, Michael Rampino, a New York University geologist, and Ken Caldeira, a scientist in the Carnegie Institution's Department of Global Ecology, offer new support linking the age of these craters with recurring mass extinctions of life, including the demise of the dinosaurs. Specifically, they show a cyclical pattern over the studied period, with both impacts and extinction events taking place every 26 million years.


This cycle has been linked to periodic motion of the Sun and planets through the dense mid-plane of our galaxy. Scientists have theorized that gravitational perturbations of the distant Oort comet cloud that surrounds the Sun lead to periodic comet showers in the inner solar system, where some comets strike the Earth.


To test their hypothesis, Rampino and Caldeira performed time-series analyses of impacts and extinctions using newly available data offering more accurate age estimates.


"The correlation between the formation of these impacts and extinction events over the past 260 million years is striking and suggests a cause-and-effect relationship," says Rampino.


Specifically, he and Caldeira found that six mass extinctions of life during the studied period correlate with times of enhanced impact cratering on Earth. One of the craters considered in the study is the large (180 km diameter) Chicxulub impact structure in the Yucatan, which dates to about 65 million years ago—the time of a great mass extinction that included the dinosaurs.


Moreover, they add, five out of the six largest impact craters of the last 260 million years on earth correlate with mass extinction events. "This cosmic cycle of death and destruction has without a doubt affected the history of life on our planet," Rampino observes.


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Evidence of ancient microbial life discovered in mantle rocks deep below the seafloor

Evidence of ancient microbial life discovered in mantle rocks deep below the seafloor | Amazing Science | Scoop.it
Ancient rocks harbored microbial life deep below the seafloor, reports a team of scientists from the Woods Hole Oceanographic Institution (WHOI), Virginia Tech, and the University of Bremen. This new evidence was contained in drilled rock samples of Earth's mantle - thrust by tectonic forces to the seafloor during the Early Cretaceous period. The new study was published today in the Proceedings of the National Academy of Sciences.


The discovery confirms a long-standing hypothesis that interactions between mantle rocks and seawater can create potential for life even in hard rocks deep below the ocean floor. The fossilized microbes are likely the same as those found at the active Lost City hydrothermal field, providing potentially important clues about the conditions that support 'intraterrestrial' life in rocks below the seafloor.


"We were initially looking at how seawater interacts with mantle rocks, and how that process generates hydrogen," said Frieder Klein, an associate scientist at WHOI and lead author of the study. "But during our analysis of the rock samples, we discovered organic-rich inclusions that contained lipids, proteins and amino acids - the building blocks of life - mummified in the surrounding minerals."


This study, which was a collaborative effort between Klein, WHOI scientists Susan Humphris, Weifu Guo and William Orsi, Esther Schwarzenbach from Virginia Tech and Florence Schubotz from the University of Bremen, focused on mantle rocks that were originally exposed to seawater approximately 125 million years ago when a large rift split the massive supercontinent known as Pangaea. The rift, which eventually evolved into the Atlantic Ocean, pulled mantle rocks from Earth's interior to the seafloor, where they underwent chemical reactions with seawater, transforming the seawater into a hydrothermal fluid.


"The hydrothermal fluid likely had a high pH and was depleted in carbon and electron acceptors," Klein said. "These extreme chemical conditions can be challenging for microbes. However, the hydrothermal fluid contained hydrogen and methane and seawater contains dissolved carbon and electron acceptors. So when you mix the two in just the right proportions, you can have the ingredients to support life."

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