May 21, 2017

Kamchatkan volcanic ash travels half the world

Volcano Mutnovsky Kamchatka, Russia.
Geochemical fingerprinting links microscopic ash found on the bottom of a Svalbard lake to volcanic event happening 7000 years ago and 5000 km away.

Eruptions are cataclysmic events that may impact people living far from their volcanic sources. Just think back to the summer of 2010, when ash from an obscure Icelandic volcano blanketed European airspace, disrupting flights for weeks.

A new study now demonstrates that volcanic ash can travel even further, linking microscopic ash from an Arctic Lake to a 7000 year old eruption on Russia`s Kamchatka peninsula.

Beyond the usual suspects

This find, recently published in the scientific journal Quaternary Science Reviews, expands the known dispersal range of volcanic ash by thousands of kilometers.

"Being both volcanically active and lying nearby, I expected our ash to originate from Iceland: this study really highlights the need to look beyond the usual suspects in this line of research," Willem van der Bilt, lead-author and researcher at the University of Bergen and the Bjerknes Centre for Climate Research points out. The results also raises questions about the factors influencing the dispersal of volcanic ash.

"The eruption that produced our ash was larger than most, but smaller than others who did not spread out their ash across the Hemisphere. Day-to-day shifts in weather factors like the speed and direction of winds surely helped this ash come such a long way," van der Bilt says.

Electron beam bombardment

To find the ash, van der Bilt and his co-authors carried out a range of delicate lab procedures in various specialized labs across Europe.

"In the end, we found and analyzed 6 particles with less than half the width of a human hair: quite literally, more than meets the eye," van der Bilt adds.

First, ash was separated from lake sediments -- like skimming off foam from milk. Next, ash was identified under a microscope and extracted during a tricky maneuver with a 10 cm long needle. Finally, in a procedure that seems to come straight from a science-fiction movie, individual ash particles were bombarded by an electron beam to determine their chemistry.

"Like human DNA, the composition of volcanic ash is unique. Geochemical analysis help us fingerprint this signature and match it with an eruption," says van der Bilt.

Time flies

But the implications of the paper go beyond challenging assumptions about the distance that volcanic ash clouds can travel. Most volcanic ash settles on the ground within weeks after an eruption, forming layers of identical age in geological records like the analyzed lake sediments.

Read more at Science Daily

Tooth truth: Human teeth tell the story of humanity through our fragile relationship with the sun

These are teeth from Megan Brickley's lab at McMaster University.
The story of humanity's vital -- and fragile -- relationship with the sun has been locked inside our teeth for hundreds of thousands of years. A new method is starting to tease out answers to major questions of evolution and migration, using clues hidden just under the enamel.

A group of McMaster University researchers, working with colleagues in Quebec and France, reveals the potential of the method in a paper in Current Anthropology.

"This is exciting because we now have a proven resource that could finally bring definitive answers to fundamental questions about the early movements and conditions of human populations -- and new information about the importance of vitamin D for modern populations," says McMaster anthropologist Megan Brickley, lead author of the paper and Canada Research Chair in the Bioarchaeology of Human Disease.

In 2016, the researchers first established that dentine -- the material that forms the bulk of the tooth -- carries a permanent record of Vitamin D deficiency, or rickets. During periods of severe deficiency, new layers of dentine cannot mineralize, leaving microscopic markers scientists can read like rings of a tree.

Those markers can tell the story of human adaptation as early man moved from equatorial Africa into lower-light regions, and may explain changes in skin pigmentation to metabolize more sunlight, or how indoor living has silently damaged human health.

Until now, there has been no reliable way to measure vitamin D deficiency over time. As the authors show with examples from ancient and modern teeth, the method is valuable for understanding a health condition that today affects more than 1 billion.

From Science Daily

May 20, 2017

Moon orbits third largest dwarf planet in our solar system

These two images, taken a year apart, reveal a moon orbiting the dwarf planet 2007 OR10. Each image, taken by the Hubble Space Telescope's Wide Field Camera 3, shows the companion in a different orbital position around its parent body. 2007 OR10 is the third-largest known dwarf planet, behind Pluto and Eris, and the largest unnamed world in the solar system. The pair is located in the Kuiper Belt, a realm of icy debris left over from the solar system's formation.
The combined power of three space observatories, including NASA's Hubble Space Telescope, has helped astronomers uncover a moon orbiting the third largest dwarf planet, catalogued as 2007 OR10. The pair resides in the frigid outskirts of our solar system called the Kuiper Belt, a realm of icy debris left over from our solar system's formation 4.6 billion years ago.

With this discovery, most of the known dwarf planets in the Kuiper Belt larger than 600 miles across have companions. These bodies provide insight into how moons formed in the young solar system.

"The discovery of satellites around all of the known large dwarf planets -- except for Sedna -- means that at the time these bodies formed billions of years ago, collisions must have been more frequent, and that's a constraint on the formation models," said Csaba Kiss of the Konkoly Observatory in Budapest, Hungary. He is the lead author of the science paper announcing the moon's discovery. "If there were frequent collisions, then it was quite easy to form these satellites."

The objects most likely slammed into each other more often because they inhabited a crowded region. "There must have been a fairly high density of objects, and some of them were massive bodies that were perturbing the orbits of smaller bodies," said team member John Stansberry of the Space Telescope Science Institute in Baltimore, Maryland. "This gravitational stirring may have nudged the bodies out of their orbits and increased their relative velocities, which may have resulted in collisions."

But the speed of the colliding objects could not have been too fast or too slow, according to the astronomers. If the impact velocity was too fast, the smash-up would have created lots of debris that could have escaped from the system; too slow and the collision would have produced only an impact crater.

Collisions in the asteroid belt, for example, are destructive because objects are traveling fast when they smash together. The asteroid belt is a region of rocky debris between the orbits of Mars and the gas giant Jupiter. Jupiter's powerful gravity speeds up the orbits of asteroids, generating violent impacts.

The team uncovered the moon in archival images of 2007 OR10 taken by Hubble's Wide Field Camera 3. Observations taken of the dwarf planet by NASA's Kepler Space Telescope first tipped off the astronomers of the possibility of a moon circling it. Kepler revealed that 2007 OR10 has a slow rotation period of 45 hours. "Typical rotation periods for Kuiper Belt Objects are under 24 hours," Kiss said. "We looked in the Hubble archive because the slower rotation period could have been caused by the gravitational tug of a moon. The initial investigator missed the moon in the Hubble images because it is very faint."

The astronomers spotted the moon in two separate Hubble observations spaced a year apart. The images show that the moon is gravitationally bound to 2007 OR10 because it moves with the dwarf planet, as seen against a background of stars. However, the two observations did not provide enough information for the astronomers to determine an orbit.

"Ironically, because we don't know the orbit, the link between the satellite and the slow rotation rate is unclear," Stansberry said.

The astronomers calculated the diameters of both objects based on observations in far-infrared light by the Herschel Space Observatory, which measured the thermal emission of the distant worlds. The dwarf planet is about 950 miles across, and the moon is estimated to be 150 miles to 250 miles in diameter. 2007 OR10, like Pluto, follows an eccentric orbit, but it is currently three times farther than Pluto is from the sun.

Read more at Science Daily

Sea level as a metronome of Earth's history

This is a view of the Mediano anticline, strata dipping to the left into the lake waters. This large-scale fold structure is a witness of ancient deformation associated with the rise of the Pyrenees in the middle Eocene, 45 Million years ago. Excellent exposure of rocks in this dry area allow today's geologists to study the epic poem of the Earth written in its sedimentary archives.
Sedimentary layers record the history of Earth. They contain stratigraphic cycles and patterns that precisely reveal the succession of climatic and tectonic conditions that have occurred over millennia, thereby enhancing our ability to understand and predict the evolution of our planet. Researchers at the University of Geneva (UNIGE), Switzerland, -- together with colleagues at the University of Lausanne (UNIL) and American and Spanish scientists -- have been working on an analytical method that combines observing deep-water sedimentary strata and measuring in them the isotopic ratio between heavy and light carbon. They have discovered that the cycles that punctuate these sedimentary successions are not, as one might think, due solely to the erosion of mountains that surround the basin, but are more ascribable to sea level changes. This research, which you can read in the journal Geology, paves the way for new uses of isotopic methods in exploration geology.

The area south of the Pyrenees is particularly suitable for studying sedimentary layers. Rocks are exposed over large distances, allowing researchers to undertake direct observation. Turbidites can be seen here: large sediment deposits formed in the past by underwater avalanches consisting of sand and gravel. "We noticed that these turbidites returned periodically, about every million years. We then wondered what the reasons for this cyclicity were," explains Sébastien Castelltort, professor in the department of earth sciences in UNIGE's faculty of sciences.

The ups and downs of oceans regulate sedimentation cycles


The geologists focused their attention on Eocene sedimentary rocks (about 50 million years ago), which was particularly hot, and undertook the isotopic profiling of the sedimentary layers. "We took a sample every 10 metres," says Louis Honegger, a researcher at UNIGE, "measuring the ratio between 13C (heavy carbon stable isotope) and 12C (light carbon stable isotope). The ratio between the two tells us about the amount of organic matter, the main consumer of 12C, which is greater when the sea level is high. The variations in the ratio helped us explore the possible link with the sea level." The research team found that the turbidite-rich intervals were associated with high 12C levels, and almost always corresponded to periods when the sea level was low. It seems that sedimentary cycles are mainly caused by the rise and fall of the sea level and not by the episodic growth of mountains.

When the sea level is high, continental margins are flooded under a layer of shallow water. Since the rivers are no longer able to flow, they begin to deposit the sediments they carry there. This is why so little material reaches the deep basins downstream. When the sea level is low, however, rivers erode their beds to lower the elevation of their mouth; they transfer their sediment directly to the continental slopes of the deep basins, creating an avalanche of sand and gravel. Consequently, if the variations of the sea level are known, it is possible to predict the presence of large sedimentary accumulations created by turbidites, which often contain large volumes of hydrocarbons, one of the holy grails of exploration geology.

Read more at Science Daily

Ghost Pepper Puree Tears a Hole in a Man's Esophagus

A word to the wise: Stay away from ghost peppers. 

A puree made from these peppers — which are infamous for their off-the-charts level of spiciness — led to a rare, life-threatening condition in an otherwise healthy, 47-year-old man in California, according to a recent report of the man's case.

Ghost peppers are among the hottest chili peppers in the world, the report said. They have a measured "heat" of more than 1 million Scoville heat units, according to the report. (For comparison, a poblano pepper measures at 2,000 Scoville units, and jalapeños come in at 5,000. Eating a single seed from a ghost pepper can cause severe burning in the mouth that lasts up to 30 minutes, the report said.

In the man's case, a ghost pepper had been pureed and served atop a hamburger as a part of an eating contest at local restaurant. After finishing the pepper-topped burger, the man drank six large glasses of water, then began "violently retching and vomiting," according to the report, which was published online in September in the Journal of Emergency Medicine.

The man ended up going to the emergency room in San Francisco because he couldn't stop vomiting, and developed severe chest and stomach pain, the authors wrote.

A CT scan of the man's chest appeared to show that his esophagus was torn and that his left lung had collapsed, so the man was sent for emergency surgery.

During the operation, the surgeons found a 2.5-centimeter (1 inch) tear in the man's esophagus. The tear was leaking food — a mix of "hamburger, onions and other green vomitus material" — into the space around the man's left lung, which had collapsed, according to the report. The surgeons repaired the man's esophagus and re-inflated his lung, then placed him on a feeding tube so that his esophagus could heal.

The man's condition, a "spontaneous esophageal rupture," which is also called Boerhaave syndrome, is "a relatively rare phenomenon," said lead study author Dr. Ann Arens, who was a physician in the department of emergency medicine at the University of California, San Francisco at the time of the man's case in the summer of 2015. (Arens is currently an emergency medicine doctor and medical toxicologist at Hennepin County Medical Center in Minneapolis.)

Spontaneous esophageal rupture is caused by violent vomiting and retching, Arens said. In other words, the man's reaction to the ghost pepper, rather than the pepper itself, caused the rupture, Arens said.

The condition is very dangerous, and is fatal in 20 to 40 percent of all cases, even when patients receive treatment, the report said. "If [the condition is] left untreated, mortality approaches 100 percent," the authors wrote.

When patients die from a ruptured esophagus, the cause of death is likely a "rapid and fatal infection," Arens told Live Science.

The man was sent home from the hospital 23 days after the operation, the report said. His feeding tube was still in place when he was sent home, but Arens said the tube was only temporary, until the esophagus healed. She said she believes the man is currently doing well.

When Arens spoke to the man after the surgery, he "did not seem keen to try [eating a ghost pepper] again," she said.

Read more at Discovery News

May 18, 2017

Newly discovered brain network offers clues to social cognition

While showing monkeys videos of social interaction, scientists scanned their brains and tracked their gaze (red dot).
Scientists call our ability to understand another person's thoughts -- to intuit their desires, read their intentions, and predict their behavior -- theory of mind. It's an essential human trait, one that is crucial to effective social interaction. But where did it come from?

Working with rhesus macaque monkeys, researchers in Winrich Freiwald's Laboratory of Neural Systems at The Rockefeller University have discovered tantalizing clues about the origins of our ability to understand what other people are thinking. As reported in Science on May 18, Freiwald and postdoc Julia Sliwa have identified areas in the brains of these primates that are exclusively dedicated to analyzing social interactions. And they may have evolved into the neural circuitry that supports theory of mind in the human brain.

The team used functional magnetic resonance imaging (fMRI) to identify those parts of the monkeys' brains that become active when the animals watched different kinds of videos.

Some of those videos showed inanimate objects (i.e., monkey toys) colliding or otherwise interacting physically. Others showed macaques interacting with the same objects by playing with them. And others still showed macaques interacting socially with other macaques: grooming, playing, fighting, etc.

By analyzing the fMRI data, the researchers were able to determine precisely which portions of the monkeys' brains responded to physical or social interactions. And much of what they found came as a surprise.

Monkey see, monkey analyze

For example, the team expected that areas containing specialized brain cells called mirror neurons, which fire when an animal performs an action such as grasping a stick or hitting a ball, or sees another animal performing the same action, would light up when the macaques watched other macaques playing with toys.

But the macaques' mirror neuron regions also showed activity when the animals watched their fellow monkeys interacting socially -- and even when they watched objects colliding with other objects.

That, says Sliwa, suggests that the motor neuron system, which also exists in the human brain, could be more involved than previously thought in understanding a variety of both social and non-social interactions.

The scientists also expected those areas of the brain that respond selectively to specific visual shapes -- namely, faces, bodies, or objects -- would be activated when the monkeys watched videos featuring those shapes. And that did indeed happen.

Surprisingly, though, the body-selective areas of the macaques' brains got an extra boost when the animals watched videos of monkeys interacting with objects. And their face-selective areas perked up even more in response to videos of monkey-on-monkey social interactions. This suggests that the same parts of the brain that are responsible for analyzing visual shapes might also be partly responsible for analyzing both physical and social interactions.

An exclusive social network

Most intriguingly, the team discovered that additional areas of the brain, far removed from those face- and body-selective areas, also lit up in response to social interactions. Digging deeper, the researchers even identified a portion of the network that responded exclusively to social interactions, remaining nearly silent in their absence.

"That was both unexpected and mind-boggling," says Freiwald, who explains that no other study has shown evidence of a network in the brain going dark when denied its preferred input.

This socially sensitive network is located in the same areas of the brain that are associated with theory of mind in humans -- areas that are similarly activated only when we reflect on the thoughts of others.

Read more at Science Daily

Icy ring surrounds young planetary system

Composite image of the Fomalhaut star system. The ALMA data, shown in orange, reveal the distant and eccentric debris disk in never-before-seen detail. The central dot is the unresolved emission from the star, which is about twice the mass of our sun. Optical data from the Hubble Space Telescope is in blue; the dark region is a coronagraphic mask, which filtered out the otherwise overwhelming light of the central star.
An international team of astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) has made the first complete millimeter-wavelength image of the ring of dusty debris surrounding the young star Fomalhaut. This remarkably well-defined band of rubble and gas is likely the result of exocomets smashing together near the outer edges of a planetary system 25 light-years from Earth.

Earlier ALMA observations of Fomalhaut -- taken in 2012 when the telescope was still under construction -- revealed only about one half of the debris disk. Though this first image was merely a test of ALMA's initial capabilities, it nonetheless provided tantalizing hints about the nature and possible origin of the disk.

The new ALMA observations offer a stunningly complete view of this glowing band of debris and also suggest that there are chemical similarities between its icy contents and comets in our own solar system.

"ALMA has given us this staggeringly clear image of a fully formed debris disk," said Meredith MacGregor, an astronomer at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass., and lead author on one of two papers accepted for publication in the Astrophysical Journal describing these observations. "We can finally see the well-defined shape of the disk, which may tell us a great deal about the underlying planetary system responsible for its highly distinctive appearance."

Fomalhaut is a relatively nearby star system and one of only about 20 in which planets have been imaged directly. The entire system is approximately 440 million years old, or about one-tenth the age of our solar system.

As revealed in the new ALMA image, a brilliant band of icy dust about 2 billion kilometers wide has formed approximately 20 billion kilometers from the star.

Debris disks are common features around young stars and represent a very dynamic and chaotic period in the history of a solar system. Astronomers believe they are formed by the ongoing collisions of comets and other planetesimals in the outer reaches of a recently formed planetary system. The leftover debris from these collisions absorbs light from its central star and reradiates that energy as a faint millimeter-wavelength glow that can be studied with ALMA.

Using the new ALMA data and detailed computer modeling, the researchers were able to calculate the precise location, width, and geometry of the disk. These parameters confirm that such a narrow ring is likely produced through the gravitational influence of planets in the system, noted MacGregor.

The new ALMA observations are also the first to definitively show "apocenter glow," a phenomenon predicted in a 2016 paper by Margaret Pan, a scientist at the Massachusetts Institute of Technology in Cambridge, who is also a co-author on the new ALMA papers. Like all objects with elongated orbits, the dusty material in the Fomalhaut disk travels more slowly when it is farthest from the star. As the dust slows down, it piles up, forming denser concentrations in the more distant portions of the disk. These dense regions can be seen by ALMA as brighter millimeter-wavelength emission.

Using the same ALMA dataset, but focusing on distinct millimeter-wavelength signals naturally emitted by molecules in space, the researchers also detected vast stores of carbon monoxide gas in precisely the same location as the debris disk.

"These data allowed us to determine that the relative abundance of carbon monoxide plus carbon dioxide around Fomalhaut is about the same as found in comets in our own solar system," said Luca Matrà with the University of Cambridge, UK, and lead author on the team's second paper. "This chemical kinship may indicate a similarity in comet formation conditions between the outer reaches of this planetary system and our own." Matrà and his colleagues believe this gas is either released from continuous comet collisions or the result of a single, large impact between supercomets hundreds of times more massive than Hale-Bopp.

The presence of this well-defined debris disk around Fomalhaut, along with its curiously familiar chemistry, may indicate that this system is undergoing its own version of the Late Heavy Bombardment, a period approximately 4 billion years ago when Earth and other planets were routinely struck by swarms of asteroids and comets left over from the formation of our solar system.

Read more at Science Daily

Self-renewing hematopoietic stem cells created for transplantation

This image shows reprogrammed hematopoietic stem cells (green) that are arising from mouse cells. These stem cells are developing close to a group of cells, called the vascular niche cells (gray), which provides them with the nurturing factors necessary for the reprogramming.
Researchers at Weill Cornell Medicine have discovered an innovative method to make an unlimited supply of healthy blood cells from the readily available cells that line blood vessels. This achievement marks the first time that any research group has generated such blood-forming stem cells.

"This is a game-changing breakthrough that brings us closer not only to treat blood disorders, but also deciphering the complex biology of stem-cell self-renewal machinery," said senior author Dr. Shahin Rafii, director of the Ansary Stem Cell Institute, chief of the Division of Regenerative Medicine and the Arthur B. Belfer Professor at Weill Cornell Medicine.

"This is exciting because it provides us with a path towards generating clinically useful quantities of normal stem cells for transplantation that may help us cure patients with genetic and acquired blood diseases," added co-senior author Dr. Joseph Scandura, an associate professor of medicine and scientific director of the Silver Myeloproliferative Neoplasms Center at Weill Cornell Medicine.

Hematopoietic stem cells (HSCs) are long-lasting cells that mature into all types of blood cells: white blood cells, red blood cells and platelets. Billions of circulating blood cells do not survive long in the body and must be continuously replenished. When this does not happen, severe blood diseases, such as anemia, bleeding or life-threatening infections, can occur. A special property of HSCs is that they can also "self-renew" to form more HSCs. This property allows just a few thousand HSCs to produce all of the blood cells a person has throughout one's life.

Researchers have long hoped to find a way to make the body produce healthy HSCs in order to cure these diseases. But this has never been accomplished, in part because scientists have been unable to engineer a nurturing environment within which stem cells can convert into new, long-lasting cells -- until now.

In a paper published May 17 in Nature, Dr. Rafii and his colleagues demonstrate a way to efficiently convert cells that line all blood vessels, called vascular endothelial cells, into abundant, fully functioning HSCs that can be transplanted to yield a lifetime supply of new, healthy blood cells. The research team also discovered that specialized types of endothelial cells serve as that nurturing environment, known as vascular niche cells, and they choreograph the new converted HSCs' self-renewal. This finding may solve one of the most longstanding questions in regenerative and reproductive medicine: How do stem cells constantly replenish their supply?

The research team showed in a 2014 Nature study that converting adult human vascular endothelial cells into hematopoietic cells was feasible. However, the team was unable to prove that they had generated true HSCs because human HSCs' function and regenerative potential can only be approximated by transplanting the cells into mice, which don't truly mimic human biology.

To address this issue, the team applied their conversion approach to mouse blood marrow transplant models that are endowed with normal immune function and where definitive evidence for HSC potential could rigorously tested. The researchers took vascular endothelial cells isolated from readily accessible adult mice organs and instructed them to overproduce certain proteins associated with blood stem-cell function. These reprogrammed cells were grown and multiplied in co-culture with the engineered vascular niche. The reprogrammed HSCs were then transplanted as single cells with their progenies into mice that had been irradiated to destroy all of their blood forming and immune systems, and then monitored to see whether or not they would self-renew and produce healthy blood cells.

Remarkably, the conversion procedure yielded a plethora of transplantable HSCs that regenerated the entire blood system in mice for the duration of their lifespans, a phenomenon known as engraftment. "We developed a fully-functioning and long-lasting blood system," said lead author Dr. Raphael Lis, an instructor in medicine and reproductive medicine at Weill Cornell Medicine. In addition, the HSC-engrafted mice developed all of the working components of the immune systems. "This is clinically important because the reprogrammed cells could be transplanted to allow patients to fight infections after marrow transplants," Dr. Lis said. The mice in the study went on to live normal-length lives and die natural deaths, with no sign of leukemia or any other blood disorders.

In collaboration with Dr. Olivier Elemento, associate director of the HRH Prince Alwaleed Bin Talal Bin Abdulaziz Al-Saud Institute for Computational Biomedicine, and Dr. Jenny Xiang, the director of Genomics Services, Dr. Rafii and his team also showed that the reprogrammed HSCs and their differentiated progenies -- including white and red bloods cells, as well as the immune cells -- were endowed with the same genetic attributes to that of normal adult stem cells. These findings suggest that the reprogramming process results in the generation of true HSCs that have genetic signature that are very similar to normal adult HSCs

The Weill Cornell Medicine team is the first to achieve cellular reprogramming to create engraftable and authentic HSCs, which have been considered the holy grail of stem cell research. "We think the difference is the vascular niche," said contributing author Dr. Jason Butler, an assistant professor of regenerative medicine at Weill Cornell Medicine. "Growing stem cells in the vascular niche puts them back into context, where they come from and multiply. We think this is why we were able to get stem cells capable of self-renewing."

If this method can be scaled up and applied to humans, it could have wide-ranging clinical implications. "It might allow us to provide healthy stem cells to patients who need bone marrow donors but have no genetic match," Dr. Scandura said. "It could lead to new ways to cure leukemia, and may help us correct genetic defects that cause blood diseases like sickle-cell anemia."

Read more at Science Daily

As Warming Takes Root, Antarctica Is Becoming Greener

Antarctica's Green Island moss bank with icebergs in the background.
The Antarctic Peninsula is undergoing a widespread transformation after a half-century of warming, fueling a “greening” at the edges of the inhospitable continent at the bottom of the world, new research concludes.

Average annual temperatures on the peninsula — the panhandle that points toward South America — have gone up nearly 3 degrees Celsius (5.4 degrees Fahrenheit) since the 1950s, when researchers started keeping detailed weather records. And the banks of moss that cover portions of the peninsula point to “a very widespread biological response” to climate change, said Matt Amesbury, a paleoclimatologist at Britain’s University of Exeter.

“Under future warming scenarios, there is likely to be a greening of the Antarctic Peninsula, both in terms of further increases in growth rates and also a likely expansion of the extent of these moss growths,” Amesbury said. As glaciers in the region continue to retreat, “It’s very likely in the future that we will see increased growth rates of the mosses, but also those mosses covering a wider area,” he said.

Amesbury is the lead author of the new study, published today in the scientific journal Current Biology.  The peninsula’s moss banks grow in the summer and freeze in the winter — and core samples from those banks give scientists a window into how the plants behaved as temperatures rose.

The 150-year record the study collected from those cores reveals how much they grew in a particular year and how well the microbes living among them thrived.

“What we see is for about the first hundred years or so, all of these different proxies kind of tick along nicely at a very low level,” Amesbury said. “And then when we get to around the 1950s or 1980s … we see a dramatic increase in these different parameters across all of our sites and all of our methods.”

The findings are a follow-up to a 2013 study that examined core samples taken from a single point on the peninsula. This study included a total of five core samples taken from the previous location and three new sites on islands offshore; all cores showed signs of increased biological activity.

“The precise timing of these shifts varied, but the prevalent pattern of change indicates a widespread biological response to increasing temperature,” the study states.

Read more at Discovery News

May 17, 2017

Large volcanic eruption may have caused the first mass extinction

These are Ordovician-Silurian marine fossils from the museum of Tohoku University.
Researchers in the USA and Japan say they may have found the cause of the first mass extinction of life.

There have been five mass extinctions since the divergent evolution of early animals 600 -450 million years ago. The cause of the third and fourth was volcanic activity, while an asteroid impact led to the fifth. But triggers of the first and second mass extinctions had, until now, been unknown.

The first mass extinction occurred at the end of the Ordovician. This age is between the divergence of the Ordovician and land invasion of vascular land plant and animals. Animals in the Ordovician-Silurian comprised marine animals like corals, trilobites, sea scorpion, orthoceras, brachiopods, graptolite, crinoid and jawless fish. Approximately 80% of species disappeared at the end of the Ordovician.

A team led by Dr. David S. Jones of Amherst College and Professor Kunio Kaiho of Tohoku University, looked into possible triggers of the first mass extinction. They took sedimentary rock samples from two places -- North America and southern China -- and analyzed the mercury (Hg) in them. They found Hg enrichments coinciding with the mass extinction in both areas.

This, they believe, is the product of large volcanic eruptions because Hg anomaly was also observed in other large igneous province volcanisms.

Huge volcanic eruptions can produce sulfate aerosols in the stratosphere. Sulfate aerosols are strong, light-reflecting aerosols, and cause global cooling. This rapid climate change is believed to be behind the loss of marine creatures.

Kaiho's team is now studying the second mass extinction in the hopes of further understanding the cause and processes behind it.

From Science Daily