Soil cannot halt climate change

 

Long-term field experiments, dating back as far as 1843, demonstrate that modern carbon emissions cannot be locked in the ground to halt global warming

Unique soils data from long-term experiments, stretching back to the middle of the nineteenth century, confirm the practical implausibility of burying carbon in the ground to halt climate change. The idea of using crops to collect more atmospheric carbon and locking it into soil organic matter to offset fossil fuel emissions was launched at COP21, the 21st annual Conference of Parties to review the United Nations Framework Convention on Climate Change in Paris in 2015.

Unique soils data from long-term experiments, stretching back to the middle of the nineteenth century, confirm the practical implausibility of burying carbon in the ground to halt climate change, an option once heralded as a breakthrough.

The findings come from an analysis of the rates of change of carbon in soil by scientists at Rothamsted Research where samples have been collected from fields since 1843. They are published today in Global Change Biology.

The idea of using crops to collect more atmospheric carbon and locking it into soil's organic matter to offset fossil fuel emissions was launched at COP21, the 21st annual Conference of Parties to review the United Nations Framework Convention on Climate Change in Paris in 2015.

The aim was to increase carbon sequestration by "four parts per 1000 (4P1000)" per year for 20 years. "The initiative was generally welcomed as laudable," says David Powlson, a soils specialist and Lawes Trust Senior Fellow at Rothamsted.

"Any contribution to climate change mitigation is to be welcomed and, perhaps more significantly, any increases in soil organic carbon will improve the quality and functioning of soil," he adds. "The initiative has been adopted by many governments, including the UK."

But there have been serious criticisms of the initiative. Many scientists argue that this rate of soil carbon sequestration is unrealistic over large areas of the planet, notes Powlson: "Also, increases in soil carbon do not continue indefinitely: they move towards a new equilibrium value and then cease."

The Rothamsted scientists used data from 16 experiments on three different soil types, giving over 110 treatment comparisons. "The results showed that the "4 per 1000" rate of increase in soil carbon can be achieved in some cases but usually only with extreme measures that would mainly be impractical or unacceptable," says Paul Poulton, lead author and an emeritus soils specialist.

"For example, large annual applications of animal manure led to increases in soil carbon that continued over many years but the amounts of manure required far exceeded acceptable limits under EU regulations and would cause massive nitrate pollution," notes Poulton.

Removing land from agriculture led to large rates of soil carbon increase in the Rothamsted experiments but doing this over large areas would be highly damaging to global food security, record the researchers.

Similarly, they add, returning crop residues to soil was effective at increasing carbon sequestration but, in some countries, this is already done so cannot be regarded as a totally new practice.

"For example, in the UK about 50% of cereal straw is currently returned to soil and much of the remainder is used for animal feed or bedding, at least some of which is later returned to soil as manure," says Poulton. "In many other countries, however, crop residues are often used as a source of fuel for cooking."

Moving from continuous arable cropping to a long-term rotation of arable crops interspersed with pasture led to significant soil carbon increases, but only where there was at least 3 years of pasture in every 5 or 6 years, record the researchers.

"Although there can be environmental benefits from such a system, most farmers find that it is uneconomic under present circumstances," says Powlson. "To make this change on a large scale would require policy decisions regarding changes to subsidy and farm support. Such a change would also have impacts on total food production."

The authors of this study conclude that promoting the "4 per 1000" initiative as a major contribution to climate change mitigation is unrealistic and potentially misleading.

They suggest that a more logical rationale for promoting practices that increase soil organic carbon is the urgent need to preserve and improve the functioning of soils, both for sustainable food security and wider ecosystem services.

For climate change mitigation through changes in agricultural practices, they point out that measures to decrease emission of nitrous oxide, a greenhouse gas almost 300 times more powerful than carbon dioxide, may be more effective.

 

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The moon formed inside a vaporized Earth synestia

 

A new explanation for the Moon origin has it forming inside the Earth when our planet was a seething, spinning cloud of vaporized rock, called a synestia. The new model resolves several problems in lunar formation.

A new explanation for the Moon origin has it forming inside the Earth when our planet was a seething, spinning cloud of vaporized rock, called a synestia. The new model led by researchers at the University of California, Davis and Harvard University resolves several problems in lunar formation and is published Feb. 28 in theJournal of Geophysical Research -- Planets

"The new work explains features of the Moon that are hard to resolve with current ideas," said Sarah Stewart, professor of Earth and Planetary Sciences at UC Davis. "The Moon is chemically almost the same as the Earth, but with some differences," she said. "This is the first model that can match the pattern of the Moon composition."
Current models of lunar formation suggest that the Moon formed as a result of a glancing blow between the early Earth and a Mars-size body, commonly called Theia. According to the model, the collision between Earth and Theia threw molten rock and metal into orbit that collided together to make the Moon.
The new theory relies instead on a synestia, a new type of planetary object proposed by Stewart and Simon Lock, graduate student at Harvard and visiting student at UC Davis, in 2017. A synestia forms when a collision between planet-sized objects results in a rapidly spinning mass of molten and vaporized rock with part of the body in orbit around itself. The whole object puffs out into a giant donut of vaporized rock.

Synestias likely don't last long -- perhaps only hundreds of years. They shrink rapidly as they radiate heat, causing rock vapor to condense into liquid, finally collapsing into a molten planet.
"Our model starts with a collision that forms a synestia," Lock said. "The Moon forms inside the vaporized Earth at temperatures of four to six thousand degrees Fahrenheit and pressures of tens of atmospheres."
An advantage of the new model, Lock said, is that there are multiple ways to form a suitable synestia -- it doesn't have to rely on a collision with the right sized object happening in exactly the right way.
Once the Earth-synestia formed, chunks of molten rock injected into orbit during the impact formed the seed for the Moon. Vaporized silicate rock condensed at the surface of the synestia and rained onto the proto-Moon, while the Earth-synestia itself gradually shrank. Eventually, the Moon would have emerged from the clouds of the synestia trailing its own atmosphere of rock vapor. The Moon inherited its composition from the Earth, but because it formed at high temperatures it lost the easily vaporized elements, explaining the Moon's distinct composition.
Additional authors on the paper are Michail Petaev and Stein Jacobsen at Harvard University, Zoe Leinhardt and Mia Mace at the University of Bristol, England and Matija Cuk, SETI Institute, Mountain View, Calif. The work was supported by grants from NASA, the U.S. Department of Energy and the UK's Natural Environment Research Council.

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Surprising new study redraws family tree of domesticated and 'wild' horses

 

New research overturns a long-held assumption that Przewalski's horses, native to the Eurasian steppes, are the last wild horse species on Earth.

 Research published in Science today overturns a long-held assumption that Przewalski's horses, native to the Eurasian steppes, are the last wild horse species on Earth. Instead, phylogenetic analysis shows Przewalski's horses are feral, descended from the earliest-known instance of horse domestication by the Botai people of northern Kazakhstan some 5,500 years ago.

Further, the new paper finds that modern domesticated horses didn't descend from the Botai horses, an assumption previously held by many scientists.

"This was a big surprise," said co-author Sandra Olsen, curator-in-charge of the archaeology division of the Biodiversity Institute and Natural History Museum at the University of Kansas, who led archaeological work at known Botai villages. "I was confident soon after we started excavating Botai sites in 1993 that we had found the earliest domesticated horses. We went about trying to prove it, but based on DNA results Botai horses didn't give rise to today's modern domesticated horses -- they gave rise to the Przewalski's horse."

The findings signify there are no longer true "wild" horses left, only feral horses that descend from horses once domesticated by humans, including Przewalski's horses and mustangs that descend from horses brought to North America by the Spanish.

"This means there are no living wild horses on Earth -- that's the sad part," said Olsen. "There are a lot of equine biologists who have been studying Przewalskis, and this will be a big shock to them. They thought they were studying the last wild horses. It's not a real loss of biodiversity -- but in our minds, it is. We thought there was one last wild species, and we're only just now aware that all wild horses went extinct."

Many of the horse bones and teeth Olsen excavated at two Botai sites in Kazakhstan, called Botai and Krasnyi Yar, were used in the phylogenetic analysis. The international team of researchers behind the paper sequenced the genomes of 20 horses from the Botai and 22 horses from across Eurasia that spanned the last 5,500 years. They compared these ancient horse genomes with already published genomes of 18 ancient and 28 modern horses.

"Phylogenetic reconstruction confirmed that domestic horses do not form a single monophyletic group as expected if descending from Botai," the authors wrote. "Earliest herded horses were the ancestors of feral Przewalski's horses but not of modern domesticates."



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Game helps players spot 'fake news'

 A game designed to help people understand how fake news and conspiracy theories spread online has been created at the University of Cambridge.

Bad Newslets players build a social media following by choosing inflammatory headlines and images to share with their imaginary fans.
Players earn achievements for impersonating celebrities and spreading misinformation.
The creators say they want the game to be a "vaccine" against fake news.
"These techniques are out there, they are being used by real people," Dr Sander van der Linden, director of the University of Cambridge Social Decision-Making Laboratory, told the BBC.
"What we're trying to do is demystify and illuminate what these techniques are, how to spot them, how to recognise them, and not be influenced by them."
While the game could teach people how to spread fake news online, Dr van der Linden said it would help people recognise the techniques used.
"If you go and see a magic show, the first time you are duped if you don't know how it works," he said.
"But when the magician explains the trick to you, you won't be fooled again the next time around."
The term fake news is often used to describe deliberately fabricated stories that are designed to mislead and influence people.
However, it has also been used by politicians to try and discredit unfavourable news coverage.
"One of the things we tried to do is keep it ideologically balanced," said Dr van der Linden.
"There's always a left [wing] path and a right path, so it's not infused with a particular ideology.
"It doesn't matter if you attack the left or the right, because you're trying to polarise people."
The BBC recently launched its own  schemeto help young people filter out fake news from the real thing.

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Watching too much television could cause fatal blood clots

 

Spending too much time in front of the television could increase your chance of developing potentially fatal blood clots known as venous thrombosis. Even trying to counterbalance hours of TV watching through adequate exercise is not effective warn researchers.

Spending too much time in front of the television could increase your chance of developing potentially fatal blood clots known as venous thrombosis. Even trying to counterbalance hours of TV watching through adequate exercise is not effective warns Yasuhiko Kubota of the University of Minnesota in the US. Kubota is the lead author of a study in Springer'sJournal of Thrombosis and Thrombolysis. Prolonged sitting can in some cases lead to blood clots because the normal circulation of blood through the legs and feet is impaired. This study focuses on the risk of developing a common and potentially fatal blood clot in the vein called venous thromboembolism (VTE). One type of VTE is known as deep vein thrombosis, where the blood clots form in the deep veins of the legs. Another serious problem is when VTE become dislodged and travel through the blood stream to block off another vein somewhere else in the body. If VTE end up in the lungs, they cause blood clots in the lungs known as pulmonary embolism (PE).

Watching television is the most common sedentary behaviour around the world, and findings from a 2016 study in Japan highlighted the increased risk of suffering a VTE related to the hours spent in front of the TV. This latest study is the first to focus on a Western population, who are known to be more prone to blood clotting conditions than people of Asian descent.
Kubota and his colleagues analyzed data from 15,158 Americans aged between 45 and 64 when the Atherosclerosis Risk in Communities Study (ARIC) started in 1987. ARIC is an ongoing population-based prospective study of blood-flow related diseases in the US. Participants were initially asked about their health status, whether they exercised or smoked, and whether they were overweight or not. Since then, ARIC team members have been in regular contact with participants, to ask about any hospital treatment they might have received. Through the analyses of hospital records and, where relevant, imaging tests, 691 incidents of VTEs were noted among the participants up to 2011.
The findings show that participants who watched television very often had more than 1.7 times the risk of suffering from a VTE compared to those who never or seldom watched TV. This risk still remained high even when factors such a person's weight or levels of exercise were taken into account.
"These results suggest that even individuals who regularly engage in physical activity should not ignore the potential harms of prolonged sedentary behaviors such as TV viewing," adds Kubota. "Avoiding frequent TV viewing, increasing physical activity and controlling body weight might be beneficial to prevent VTE."



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Neuroscientists identify the smallest units that make up the vocalization of marmoset monkeys

 

From short 'tsiks' and 'ekks' to drawn-out 'phees' -- all the sounds produced by marmoset monkeys are made up of individual syllables of fixed length, according to a new study. The smallest units of vocalization and their rhythmic production in the brain of our relatives could also have been a prerequisite of human speech.

"Seven times a second, our speech apparatus can form a syllable," says Steffen Hage. Regardless if it is Batman shouting 'Ha!' or Mary Poppins singing 'Supercalifragilisticexpialidocious': when we speak, our utterance is made up of small units that are on average a seventh of a second long. This rhythm inherent in our production of syllables is as much constrained by the structure of our voicebox as it results from the processes that control speech in the brain. These biological fundamentals of speech may have been very similar in our ancestors.
 If we want to understand the evolution of human speech, we should look into its biological basis in our close relatives in the animal kingdom: primates. However, we still do not have a sufficient understanding of their vocalisation. To come to grips with the neurobiological basis of primate vocalisation, Hage's neuroscientific research group works with marmoset monkeys, a primate species from South America. Marmosets are far closer related to us than, for example,perching birds, whose vocalisation has been the focus of much research into the rhythm and length of syllables.
The researchers recorded thousands of instances of the little monkeys' 'tsiks', 'ekks' and 'phees' in a sound chamber. They interrupted the animals' natural vocalisation with white noise at irregular intervals. The researchers effectively 'talked over' the monkeys, causing them to fall quiet.
Thomas Pomberger, one of the study's authors, explains the results: "The marmosets' 'phee' had so far been considered part of their basic vocabulary, alongside the 'tsik' and 'ekk'. We observed that they would stop right in the middle of their 'phee' calls when we disrupted them with noise. Moreover, that would only happen at specific points within the call."
Co-author Cristina Risueno-Segovia adds: "What we found was that what had been known as a long 'phee' call actually consists of small units of about the same length as a 'tsik' or 'ekk' -- about 100 milliseconds." Their supervisor Hage says: "Until now, the supposed existence of the long 'phee' has not allowed for the conclusion that we can draw now: just like us, marmoset monkeys have a 'hardwired' rhythm that controls their vocalisation. It is even similarly fast."
Such a rhythm might be an evolutionary prerequisite on the path to developing true speech. The new study demonstrates that research in marmosets can provide the necessary clues to better understand the origins and properties of human speech -- a question that has been much debated in the scientific community.

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Researcher discovered how genetic variants in taste receptors related to sweet preference

 

The types of snacks a child chooses could be linked to genetics, a new study found. The study investigated whether genetic variants in taste receptors related to sweet, fat and bitter tastes influence the snacks preschoolers choose and found nearly 80 per cent carried at least one of these genotypes that could predispose them to poor snacking habits. These findings could help parents tailor their kids' diets based on their genetics of taste.

Whether your child asks for crackers, cookies or veggies to snack on could be linked to genetics, according to new findings from the Guelph Family Health Study at the University of Guelph.
Researcher Elie Chamoun investigated whether genetic variants in taste receptors related to sweet preference, fat taste sensitivity and aversion to bitter green leafy vegetables influence the snacks chosen by preschoolers. He found that nearly 80 per cent of preschoolers in the study carried at least one of these potential at-risk genotypes that could predispose them to poor snacking habits.
"Kids are eating a lot more snacks now than they used to, and we think looking at how genetics can be related to snacking behaviour is important to understanding increased obesity among kids," said Chamoun, a PhD candidate in the Department of Human Health and Nutritional Sciences and a member of the Guelph Family Health Study. "This new research could help parents understand how their kids taste, and tailor their diet for better nutritional choices."

 



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