New evidence suggests our understanding of how Earth's mantle moves is wrong

Hello My friend

New evidence suggests our understanding of how Earth's mantle moves is wrong

Science gonna science.

You might think geologists have a pretty good idea about the inner workings of the Earth's mantle - that hot, rocky region between the crust and the core thatmakes up 84 percent of the total volume of our planet.

But a new study suggests that the mantle's movement could be affected by factors we haven't even yet considered yet, and that could completely change our thinking about earthquakes, volcanoes, and other plate-shifting events.

The new research, conducted by a team from the University of Columbia, focusses on two layers: the lithosphere, which holds the crust, the upper mantle, and the tectonic plates that slowly slide across Earth's surface; and the deeperasthenosphere, a hotter and more viscous part of the mantle believed to help drive the movement of the plates above.

Until now, it was thought that major pulls and pushes in tectonic plates - caused by rising and sinking sections of the lithosphere - were what triggered the majority of the movement underneath in the asthenosphere. Now it appears that smaller, more independent factors could have an influence, too.

The researchers attached an array of seismometers on the floor of the Pacific Ocean to get a closer look at mantle convection and plate tectonics based on the vibrations detected from earthquakes.

In particular, they looked at patterns created in crystals called olivine - patterns that are dictated by the flow of Earth's mantle, and which can be deciphered from the speed of seismic waves.

Surprisingly, the olivine patterns didn't match with the movements of tectonic plates, and were apparently not hugely affected by those major pulls and pushes in the lithosphere above. The main flow of movement seemed to be happening 250 kilometres (155 miles) down.

Jose F. Vigil/USGS

The team thinks that pressure caused by different temperatures inside the mantle could be causing small-scale convection. Essentially, these small-scale processes could be more significant than the plate-driven deformation higher up in the mantle.

"Our data suggests that there are two other processes in the mantle that are stronger [than the influence of moving plates]," explains study co-author and geophysicist, James Gaherty.

"One, the asthenosphere is clearly flowing on its own, but it's deeper and smaller scale; and, two, seafloor spreading at the ridge produces a very strong lithospheric fabric that cannot be ignored."

It's still not clear exactly how the asthenosphere works and in which directions its materials are flowing, but there's now a solid foundation for future study. The team's work has been published in Nature.

And that's not the only recent discovery that sheds new light on what's going on below Earth's surface. Last month, researchers from Arizona State University found that two large 'blobs' sitting inside the planet - each the size of a continent and about 2,900 kilometres (1,800 miles) down - are made of a different material than the rest of the mantle.

"While the origin and composition of the blobs are yet unknown, we suspect they hold important clues as to how Earth was formed and how it works today,"explained one of the team, Edward Garnero. It's possible that these previously undetected blobs also have a role to play in the movements of the mantle being analysed in the first study we mentioned.

Again, the speeds of seismic waves were used to determine that these blobs are made up of different stuff - whatever it turns out to be - than the materials around them. These new findings have been published in Nature Geoscience.

Dolly the Sheep scientist says a biobank for endangered animals could be a real-life Noah's Ark

Hello My friend 

Dolly the Sheep scientist says a biobank for endangered animals could be a real-life Noah's Ark

Genius!

The chief scientist behind the creation of Dolly the Sheep – the world's first mammal cloned from an adult somatic cell – has called for the establishment of a biobank to preserve the biological tissue of endangered animals.

Speaking on the eve of the 20th anniversary of Dolly's birth on 5 July 1996, Sir Ian Wilmut said a modern-day Noah's Ark – functioning much like an animal-focused version of the 'Doomsday' Svalbard Global Seed Vault in Norway – could help save species from extinction.

"The absolute minimum we should do is preserve tissues from these animals in such a way they can be thawed and grown again," Wilmut, an embryologist from the University of Edinburgh in the UK, told the media.

Such a facility could preserve matter such as animal eggs and sperm, which could hypothetically help scientists to effectively resurrect species if they become extinct in the future.

But while researchers might one day be able to make viable embryos from stored cells and tissues, Wilmut acknowledges large gains would first need to be made in biological science – especially since a living surrogate female animal from another species would be needed to carry and give birth to any animal produced by the procedure.

If those issues can be addressed, Wilmut said the kinds of advances being made in induced pluripotent stem cells (iPS) – which scientists can use to generate all other kinds of cells in the body – could make an animal biobank a viable way to produce living animals.

"We are looking some distance into the future, but people are beginning to develop abilities to produce gametes (sperm and egg cells) from iPS cells," said Wilmut. "I would presume that one day, with the species which are really studied, we will be able to produce gametes, and therefore embryos."

Another means of resurrecting extinct animal species could lie in genetic editing processes, Wilmut said. Techniques such as CRISPR, which allow scientists to cut, copy, and paste individual fragments of an organism's DNA, might be able to make incremental changes to a living species over the course of several generations, until the species begins to genetically resemble an extinct species.

There's been a lot of controversy over the use of CRISPR in humans, since the genetic changes scientists introduce will persist in future generations, but Wilmut says he is against the idea of banning the procedure outright.

"I think as a principle there shouldn't be a simple red line that says 'no we don't'. The question is what's the benefit, what's the risk of mishap and does the one thing justify the other?" he said. "If there's a procedure that would enable you to either correct a disease or enhance somebody in some way, and approved within a broad context, then I would be in favour of it."

So far, scientists have had mixed results with resurrecting animal species, suggesting that we still have a way to go before we really know what we're doing.

Last year, researchers successfully implanted mammoth DNA into functioning elephant cells in petri dish as an experiment, but many previous attempts to bring back extinct animals have resulted in serious physical defects – with a Pyrenean ibex (aka bucardo) cloned in 2003 lasting only 7 minutes before dying of breathing difficulties.

While Wilmut advocates cloning science for the benefit of preserving endangered species, he's doubtful about the idea of people cloning their own pets. Last year, a couple in the UK paid a South Korean cloning companyapproximately US$100,000 to clone their boxer, Dylan, who died of a heart attack.

Wilmut says a pet's personality is a natural product of its upbringing, and in any case, the movement of cells during foetal development would likely ensure that no cloned animal would ever produce a perfect visual match to the original pet.

"[Y]ou can't clone a personality… In appearance and certainly personality it's likely to be very different," he said. "So people should consider whether they want to go away and buy another pet instead by natural means. It will probably be just as similar as a clone."

The top six dinosaur myths, debunked

Hello My friend

The top six dinosaur myths, debunked

We've all believed at least one of these...

When the first dinosaur bone was described in 1676, it was thought to come from an elephant or perhaps a giant. Over a century later, scientists realised such fossils came from a creature they named Megalosaurus, portrayed as a sort of stocky, overgrown lizard.

Then, in 1842, leading anatomist Richard Owen recognised Megalosaurus as part of a whole new group of animals, which he named Dinosauria, or "Terrible Lizards".

Since then, around 700 different dinosaur species have been described, withmore found every month. Our ideas about dinosaurs have also changed radically. The dinosaurs we know today are very different from the ones in the books you may have read as a child.

Myth 1: Dinosaurs were all big

The name dinosaur tends to evoke images of giants – and certainly many were very large.Tyrannosaurus rex was around 12 metres (39 feet) long and weighed more than five tonnes (11,000 pounds), the size of an elephant, and it probably wasn’t even the biggest carnivore. Long-necked, plant-eating sauropods grew to titanic proportions.

The enormous Argentinosaurus is known from just a few bones, but its size has been estimated at 30 metres (98 feet) in length and 80 tonnes in weight. That’s larger than any living land mammal and all but the largest whales. And dinosaurs are unique here. No other group of land animals before or since was able to grow as large.

But not all dinosaurs were giants. The horned dinosaur Protoceratops was the size of a sheep.Velociraptor was the size of a golden retriever and had to be scaled up for Jurassic Park to make it more terrifying.

Recent years have seen an explosion in the number of small species discovered, such as the cat-sized raptor Hesperonychus, the rabbit-sized plant-eaterTianyulong, and the quail-sized insect-eater Parvicursor.

The smaller species were probably more common than their giant cousins. It’s just that the massive bones of a T. rex are more likely to have been preserved and a lot easier to spot in the field.

Myth 2: Dinosaurs were all scaly

When dinosaurs were first discovered, it seemed obvious that because they were related to crocodiles and lizards, they must have been scaly. And many dinosaurs – including duckbills, horned dinosaurs, sauropods, and armoured dinosaurs – do preserve scale impressions.

But in the 1970s, palaeontologists began wondering if some dinosaurs might have been feathered, like their bird relatives.

This was considered wild speculation at the time, but in 1997 a small carnivorous dinosaur named Sinosauropteryx was found to be covered not with scales, but a soft, fuzzy down.

Since then, feathers have been discovered on the plant-eating ornithopods, fanged heterodontosaurs, and many families of carnivorous dinosaurs including Tyrannosauridae - meaning that T. rex was probably covered in feathers, not scales.

Myth 3: Dinosaurs were all green and brown

Early paintings of dinosaurs favoured a drab palette, with monotone animals dressed in depressing shades of grey, green, and brown. If the Mesozoic era really was that dreary, no wonder they went extinct. But in reality, the colours would have been much more vibrant, even garish.

Studies of dinosaur scales and feathers have revealed traces of melanin, the same pigment that lends colour to lizard scales, bird feathers and our hair. Analyses show that dinosaurs came in a wide variety of colours including black, white, and ginger. A few show-offs even had an iridescent sheen to their feathers.

Not only that, but many dinosaurs were boldly patterned with spots and stripes, white bellies and dark backs. Some of these patterns probably evolved as camouflage, to help dinosaurs hide from predators and prey. But bright colours and conspicuous patterns would have served to draw the eye of potential mates, much like the tail of a peacock.

Myth 4: Dinosaurs were bad parents

Most reptiles simply bury their eggs and walk away, leaving their offspring to fend for themselves as best they can. This hands-off parenting is risky. A sea turtle must lay thousands of eggs over its lifespan to see a few grow up.

Dinosaurs were once thought to use the same 'lay 'em and leave 'em' strategy. We now know that’s wrong.

Living dinosaur relatives – birds and crocodiles – guard their eggs and their young, so it’s a reasonable assumption that the dinosaurs did as well. And there’s now evidence of this.

When expeditions to the Gobi Desert found a dinosaur atop a clutch of eggs, it was assumed to have died while plundering the nest. It was named Oviraptor, or "egg thief". But then more skeletons were found atop clutches of eggs, sitting on them like brooding birds. It turns out Oviraptor didn’t eat eggs - it was guarding them.

Myth 5: Dinosaurs were doomed to extinction

Dinosaur extinction was long blamed on some failure of the dinosaurs themselves, a failure to adapt to the changing environment. In reality, dinosaurs were diverse for more than 100 million years with fossils found in North and South America, Asia, Europe, Africa, and even Antarctica.

Although some argue this diversity was in decline, the fossils show that dinosaurs remained widespread, common and diverse until 66 million years ago, when an asteroid struck Earth in what is now Mexico. Debris from the impact blocked out the sun and plunged the world into darkness.

The disappearance of the dinosaurs wasn’t fated – it was a cosmic accident. If the asteroid had deviated by a fraction of a fraction of a degree, dinosaurs would still rule the planet – and we wouldn’t.

Myth 6: Dinosaurs all became extinct

The asteroid wiped out the dinosaurs, almost. T. rex, Triceratops and the rest disappeared, but a handful of small feathered dinosaurs, probably less than a dozen species, survived.

They were birds - small, flying cousins of T. rex and Velociraptor and the direct descendants of the carnivorous dinosaurs. And they not only survived but thrived, evolving into some ten thousand species of birds.

Nick Longrich, Senior lecturer, palaeontology, University of Bath.

This article was originally published by The Conversation. Read the original.

93% of mammals were likely killed off with the dinosaurs

Hello My friend

93% of mammals were likely killed off with the dinosaurs

Way to go, asteroid.

A new study suggests that a whopping 93 percent of mammals died alongside the dinosaurs 66 million years ago, when a colossal asteroid struck Earth.

Contrary to the popular assumption that mammals fared way better than the dinosaurs during this cataclysmic event - which is supported by the fact that they're so prevalent in the fossil record shortly after the event - new research shows there's more to the story than we thought.

Researchers from the University of Bath in the UK analysed the fossil record 2 million years before the Cretaceous-Paleogene boundary - the point in time when a suspected asteroid collided with Earth, wiping out non-avian dinosaurs like T. rex and Triceratops, and pretty much everything else.

They then looked at the fossil record up to 300,000 years afterwards, to see how many mammals died out and how quickly they rebounded.

The evidence suggests that 93 percent of mammals died out after the asteroid struck, says the team, though those that did survive were able to adapt after the disaster, and as a result, managed to rebound quickly.

In fact, merely 300,000 years after the collision - an extremely short amount of time, evolutionarily speaking - the amount of mammal species had doubled, compared to how many were around before the asteroid.

The team’s findings help explain why we have this misconception that many mammals went unscathed by the asteroid. Instead, says the team, it was quite the opposite, because mammals were hit harder than other types of animals, such as lizards, turtles, and crocodiles.

The problem largely stems from the fact that mammals were so adaptable that they appeared - at first glance - to have never vanished.

"The fossil record is biased in favour of the species that survived. As bad as things looked before, including more data shows the extinction was more severe than previously believed," said team member Nick Longrich. "It wasn't low extinction rates, but the ability to recover and adapt in the aftermath that led the mammals to take over."

So how did the mammals pull off such an amazing comeback, while most other land-based creatures did not?

Well, the biggest advantage that mammals had over non-avian dinosaurs was size. Around 66 million years ago, mammals were extremely small, compared to today’s standards. In fact, the ones that survived the asteroid were likely the same size or smaller than an average house cat, the team reports.

Their small size meant that they could scavenge for food and hide from other predators. Basically, with a good chunk of the dinosaurs gone - or at least on their way out - the few mammals that survived were able to hide and hunt in a new world that they adapted to so fast, the fossil record makes it seem like they never left at all.

"Because mammals did so well after the extinction, we have tended to assume that it didn't hit them as hard," Longrich said. "However, our analysis shows that the mammals were hit harder than most groups of animals, such as lizards, turtles, crocodilians, but they proved to be far more adaptable in the aftermath."

The team also reports that the surviving mammals adapted differently in different parts of the world, producing a variety of different species.

"You might expect to see the same few survivors all across the continent. But that's not what we found," said Longrich. "After this extinction event, there was an explosion of diversity, and it was driven by having different evolutionary experiments going on simultaneously in different locations."

"This may have helped drive the recovery. With so many different species evolving in different directions in different parts of the world, evolution was more likely to stumble across new evolutionary path," he added.

The new study comes at a good time, too, because researchers from Curtin University in Australia are currently digging inside the Chicxulub Impact Crater in the Gulf of Mexico - the site where the deadly asteroid fell 66 million years ago, releasing the same amount of energy as 100 million nuclear bombs in the process - to see how life evolved in the moments afterwards.

Hopefully, with new research shining more light on the subject, we'll one day understand how the asteroid strike led to the end of the dinosaurs, and how life across the globe rebounded, especially since researchers are still debating if the asteroid is singlehandedly to blame or not.

The study was published in the Journal of Evolutionary Biology.

Researchers have discovered a new life form in our saliva, and it's linked to human disease

Hello My friend

Researchers have discovered a new life form in our saliva, and it's linked to human disease

Holy crap.

Researchers in the US have discovered a brand new life form hiding inside our saliva – a type of parasitic bacteria called Bdellovibrio.

The bacterium only has 700 genes and is the first strain ever discovered that's completely dependent on other bacterium for survival. If that wasn't creepy enough, this new life form has also been linked to a whole range of human diseases, including gum disease, cystic fibrosis, and antimicrobial resistance. 

The new parasite was discovered after scientists from the University of Washington School of Dentistry discovered a mysterious fragment of RNA in human saliva tests that didn't match any known organisms.

Other labs had found the same strange RNA code in the past, but no one had been able to figure out where it came from. But after studying it more closely, the team was able to show that this RNA belonged to a tiny bacterium that's actually living on another, better known strain: Actinomyces odontolyticus. 

Although scientists have found bacteria that can infect other bacteria in the past, this is the first time they've ever discovered a strain that's entirely dependent on infecting its host, because it can't make its own amino acids that are essential for life.

That's why it was so hard for scientists to identify it - they can't grow it and keep it alive in the lab without a host.

"They’re ultra-small bacteria, and live on the surface of other bacteria," lead researcher Jeff McLean told the annual meeting of the American Society for Microbiology in Boston last week, as Andy Coghlan reports for New Scientist. 

By studying the parasite in the lab alongside its host, the team has now shown that Bdellovibrio is a free-living cell that hunts down Actinomyces and attaches to its outer membrane.

At first, Actinomyces can handle the parasites, which suck the nutrients out of it. But eventually it succumbs and is killed by the attack. The team still isn't sure how Bdellovibrio reproduces and spreads to its next victim. 

"We're trying to decipher what's going on," said lead researcher Jeff McLean.

But what the team is now interested in is how Bdellovibrio might affect human disease - they found high concentrations of the parasite's DNA in people with gum disease and cystic fibrosis.

Previous research has shown that Actinomyces odontolyticus contributes to gum disease, and when the new parasite is added, it seems to make Actinomycesbetter able to evade white blood cells, which of course means the body is less capable of fighting off the infection.

The host bacterium also become more resistant to the antibiotic streptomycin too, the researchers found.

They'll now be investigating the relationship further, to try to figure out how the presence of the parasitic bacterium might affect human health, and how we can use this knowledge to improve disease outcomes. 

While McLean and his colleagues have presented their findings to the annual meeting of the American Society for Microbiology, it hasn't been peer-reviewed as yet, so we need to wait for other researchers to confirm the discovery. But scientists are already pretty excited about it.

Geobiologist Roland Hatzenpichler from the California Institute of Technology, who wasn't involved in the study, told New Scientist it could be the "tip of the iceberg" for microbes like this.

And it's unlikely to be the last discovery to come from the saliva in our mouths, as scientists think as many as half the microbes in our spit are yet to be properly identified.

"It's incredibly exciting to see such a major advancement in the study of major lineages of life that until now have been impossible to cultivate," Brian Hedlund from the University of Nevada in Las Vegas, who also wasn't involved in the study, told New Scientist.

"Gene data from other as-yet uncultivated organisms suggests that host-parasite relationships between microbes are common in nature, so this type of study is a great template for others to follow."