Full Moon photograph taken 10-22-2010 from Madison, Alabama, USA. Photographed with a Celestron 9.25 Schmidt-Cassegrain telescope.
With an estimated 1.6 billion tonnes of water ice at its poles and an abundance of rare-earth elements hidden below its surface, the Moon is rich ground for mining.
In this month’s issue of Physics World, science writer Richard Corfield explains how private firms and space agencies are dreaming of tapping into these lucrative resources and turning the Moon’s grey, barren landscape into a money-making conveyer belt.
Since NASA disbanded its manned Apollo missions to the Moon over 40 years ago, unmanned spaceflight has made giant strides and has identified a bountiful supply of water ice at the north and south poles of the Moon.
“It is this, more than anything else,” Cornfield writes, “that has kindled interest in mining the Moon, for where there is ice, there is fuel.”
Texas-based Shackleton Energy Company (SEC) plans to mine the vast reserves of water ice and convert it into rocket propellant in the form of hydrogen and oxygen, which would then be sold to space partners in low Earth orbit.
As the company’s chief executive officer, Dale Tietz, explains, the plan is to build a “gas station in space” in which rocket propellant will be sold at prices significantly lower than the cost of sending fuel from Earth.
SEC plans to extract the water ice by sending humans and robots to mine the lunar poles, and then use some of the converted products to power mining hoppers, lunar rovers and life support for its own activities.
Moon Express, another privately funded lunar-resources company, is also interested in using water ice as fuel — but in a different form. It plans to fuel its operations and spacecraft using “high-test peroxide” (HTP), which has a long and illustrious history as a propellant.
As for mining the rare-earth elements on the Moon, China is making the most noticeable headway. The Jade Rabbit lander successfully touched down on the Moon in December 2013 and the Chinese space agency has publicly suggested establishing a “base on the Moon as we did in the South Pole and the North Pole.”
With a near-monopoly on the dwindling terrestrial rare-earth elements, which are vital for everything from mobile phones to computers and car batteries, it is no surprise that China may want to cast its net wider.
“All interested parties agree that the Moon — one step from Earth — is the essential first toehold for humankind’s diaspora to the stars,” Corfield concludes.
The structural engineer strides through Kathmandu’s old city, past buildings reduced to rubble, buildings whose facades are cracked in dozens of places, like the fractured shell of a hardboiled egg. But it’s the many buildings that made it unscathed through the earthquake that amaze Kit Miyamoto.
“It could have been so much worse,” said Miyamoto, head of a global earthquake and structural engineering firm, who flew to Nepal soon after he heard about last weekend’s 7.8- magnitude quake. He shakes his head, topped by a white hardhat. Before landing, he’d envisioned a flattened moonscape of dust and debris. He thought as many as 40,000 people could be dead.
That the reality has turned out to be far less destructive has a lot to do with the vagaries of geology, geography and construction decisions. Not to mention sheer luck.
The danger, however, may not be over. Dozens of mostly small aftershocks have hit Nepal since the quake. A more powerful aftershock a bit closer to the capital could cause immense damage.
“If a magnitude 6 or 6.5 quake happens within 20 kilometers of Kathmandu, it’s going to be a nightmare,” said Sandeep Donald Shah, a structural engineer with Miyamoto International, during the walk through Kathmandu. “The probability is pretty high that this may happen because we just had a (huge) earthquake, and the fault line has been activated.”
The general state of Kathmandu’s buildings—with their ancient soot-and-exhaust-stained concrete, their uneven bricks, their drooping facades and crooked balconies—raises questions about how so many still stand after such a big quake.
Remaining upright depended on a combination of factors, including age, size, building material and strength, location and the underlying soil. But the simplest explanation is that Kathmandu largely sits outside the danger zone of last week’s quake.
Because the epicenter was about 80 kilometers (50 miles) from the capital, the quake’s power had partially dissipated by the time it got to Kathmandu, said Miyamoto, who is also a seismic safety commissioner for the state of California.
Even so, some of Kathmandu’s remaining buildings look “very bad, seismically speaking,” with weak foundations and structures, Miyamoto said. They’ve also been “softened up” by the quake, making them more likely to collapse or be seriously damaged if another, closer quake hits.
The region will likely see aftershocks for another year, including some big ones, Miyamoto said, but it’s impossible to predict where or when they will occur. The two biggest aftershocks so far have been more than 60 kilometers (38 miles) from Kathmandu.
A direct or even a near hit on Kathmandu by the April 25 quake would have meant a massive death toll.
The Nepal quake released 16 times the energy of the 2010 Haiti earthquake, where death estimates ranged from 100,000 to 300,000, yet the death toll in Nepal now stands at more than 6,600. This is a huge loss of life, but far less than recent estimates that 100,000 people might die in Nepal’s next major earthquake.
Driving through the city, the juxtaposition of what crumbled and what survived is striking.
At some big hotel compounds it’s almost as if the quake never happened: honking geese wander over manicured lawns and foreign guests start their days with hot showers before lining up at brimming breakfast buffets, eyes locked on phones connected to Wi-Fi.
Outside the gates, even many of those whose homes weren’t ruined slept out in the open for days after the quake because of fears of aftershocks. In some closely packed quarters, there is spectacular damage, with tall buildings leaning against their neighbors like tipped dominoes. Many villages in the countryside, outside the capital, have been virtually flattened.
Generally, the older and bigger the building, the worse off it fared. So the so-called old city, home to many of Kathmandu’s precious world heritage buildings, is obliterated in places. All over the city, destroyed brick walls spill into the streets like ocean waves breaking on beaches.
In much of Kathmandu, however, roads are choked with traffic, and businesses have begun to reopen. You can go blocks sometimes without seeing any obvious earthquake damage.
“It’s getting back to normal, but … it still doesn’t feel safe,” said Prabhu Dutta, a 27-year-old banker in Kathmandu.
He has started sleeping again inside his home, which has some cracks in the walls but is still standing. However, the dozens of aftershocks he has felt since the quake make him uneasy. Many people in Kathmandu have been leaving for the countryside because of fears of a big aftershock.
In the final equation, buildings collapse, or stand, because of the power and length of a quake’s shaking.
The strength of the shaking depends on the magnitude of the earthquake, the distance from the epicenter, the depth of the earthquake—shallower quakes do more damage than deeper ones—and the type of soil, according to Susan Cutter, director of the Hazards and Vulnerability Research Institute at the University of South Carolina.
While both the Haiti and Nepal quakes were shallow—10 kilometers (6 miles) deep for Nepal, 13 kilometers (8 miles) for Haiti—the soil in Haiti made the shaking more severe and longer, Cutter said. Port-au-Prince was also much closer to the epicenter than Kathmandu—25 kilometers (15 miles) rather than 80 kilometers (50 miles).
Old or unreinforced masonry normally fares poorly in an earthquake, though much depends on the quality of the materials and the building methods, as well as on building codes and their enforcement. If Nepal is far below most Western nations in terms of construction quality and code enforcement, most experts also believe it is better than Haiti.
Miyamoto, the structural engineer, called the damage in Nepal’s capital, and the possibility that aftershocks could cause much more, a wakeup call. The government and outside nations, he said, should begin work to strengthen existing buildings and construct stronger new ones.
But that may prove difficult for Nepal’s leaders.
After the quake, as he stood outside a multi-story home where emergency teams were pulling out the body of a 12-year-old girl, Transport Minister Tek Bahadur Garung said that while Nepal does issue building regulations and licenses, there’s no monitoring or enforcement.
Officials, he said, were simply overwhelmed.
“In this situation, what to do?” he said. “It’s a big problem for our government to solve.”
Now extinct, woolly mammoths lived during the last ice age. Credit: Natural History Museum, London/SPL
Unlike their elephant cousins, woolly mammoths were creatures of the cold, with long hairy coats, thick layers of fat and small ears that kept heat loss to a minimum. For the first time, scientists have comprehensively catalogued the hundreds of genetic mutations that gave rise to these differences.
The research reveals how woolly mammoths (Mammuthus primigenius) evolved from the ancestor they share with Asian elephants (Elephas maximus). It could even serve as a recipe for engineering elephants that are able to survive in Siberia.
“These are genes we would need to alter in an elephant genome to create an animal that was mostly an elephant, but actually able to survive somewhere cold,” says Beth Shapiro, an evolutionary geneticist at the University of California, Santa Cruz who was not involved in the latest research. As fanciful as it sounds, such an effort is at a very early stage in a research lab in Boston, Massachusetts.
The first woolly mammoth genome was published in 2008 (ref. 2), but it contained too many errors to reliably distinguish how the mammoth genome differs from those of elephants. Other studies singled out individual mammoth genes for close inspection, identifying mutations that would have endowed the animals with light coats3 and oxygen-carrying haemoglobin proteins that work in the cold4.
In the latest study, Vincent Lynch, an evolutionary geneticist at the University of Chicago in Illinois, and his team describe how they sequenced the genomes of three Asian elephants and two woolly mammoths (one died 20,000 years ago, another 60,000 years ago) to a very high quality. They found about 1.4 million DNA letters that differ between mammoths and elephants, which altered the sequence of more than 1,600 protein-coding genes. The study was posted on the biology preprint server bioRxiv.org on 23 April1.
Combing the literature for information about what those proteins do in other organisms revealed dozens of genes implicated in skin and hair development, fat storage and metabolism, temperature sensation and other aspects of biology potentially relevant to life in the Arctic.
For instance, several of the genes with changes unique to the mammoths were involved in setting the circadian clock, a potential adaptation to living in a world with dark winters and 24 hours of daylight in summer. Other Arctic animals such as some reindeer have similar mutations.
The mammoth genomes also contained extra copies of a gene that controls the production of fat cells and variations in genes linked to insulin signalling, which are in turn linked to diabetes and diabetes prevention. And several of the genes that differ between mammoths and elephants are involved in sensing heat and transmitting that information to the brain.
Resurrected gene
The team ‘resurrected’ the mammoth version of one of the heat-sensing genes, which encodes a protein called TRPV3 that is expressed in skin and also regulates hair growth. They inserted the gene sequence into the genomes of human cells in the lab and exposed them to different temperatures, revealing that the mammoth TRPV3 protein is less responsive to heat than the elephant version is. The result chimes with a previous finding that mice with a deactivated version of TRPV3 are more likely to spend time in colder parts of their cage compared with normal rodents, and boast wavier hair.
The next step, says Lynch, is to insert the same gene into elephant cells that have been chemically programmed to behave like embryonic cells, and so can be turned into a variety of cell types. Such induced pluripotent stem (iPS) cells could then be used to examine expression of mammoth proteins in different tissues. Lynch’s team also plans to test the effects of other mammoth mutations in iPS cells.
Mammoth task
Similar work is already being carried out in the lab of George Church, a geneticist at Harvard Medical School in Boston. Using a technology known as CRISPR/Cas9 that allows genes to be easily edited, his team claims to have engineered elephant cells that contain the mammoth version of 14 genes potentially involved in cold tolerance — although the team has not yet tested how this affects the elephant cells. Church plans to do these experiments in “organoids” created from elephant iPS cells.
The work, says Church, is a preamble to editing an entire woolly mammoth genome — and perhaps even resurrecting the woolly mammoth, or at least giving an Asian elephant enough mammoth genes to survive in the Arctic. The second option would be easier to do because it would require fewer mutations than the first option. A 16-square-kilometre reserve in north Siberia, known as Pleistocene Park, has even been proposed as a potential home for such a population of cold-tolerant elephants.
However, whether anyone would want to do such a thing is a different question, says Lynch, and Shapiro agrees. In her book How to Clone a Mammoth (Princeton University Press, 2015), she outlines the innumerable hurdles that stand in the way of breeding genetically modified ‘woolly elephants’ — from the ethics of applying reproductive technologies to an endangered species to the fact that the field of elephant reproductive biology is still immature.
“I probably should have called the book How One Might Go About Cloning a Mammoth (Should It Become Technically Possible, And If It Were, In Fact, a Good Idea, Which It’s Probably Not),” Shapiro says. “But that was a much less compelling title.”
Note : The above story is based on materials provided by Nature. The original article was written by Ewen Callaway.
This custom-built precise pressure sensor detects the seafloor’s rise and fall as magma, or molten rock, moves in and out of the underlying magma chamber. Three are installed on the caldera of the underwater volcano. Credit: NSF-OOI/UW/CSSF
If a volcano erupts at the bottom of the sea, does anybody see it? If that volcano is Axial Seamount, about 300 miles offshore and 1 mile deep, the answer is now: yes.
Thanks to a set of high-tech instruments installed last summer by the University of Washington to bring the deep sea online, what appears to be an eruption of Axial Volcano on April 23 was observed in real time by scientists on shore.
“It was an astonishing experience to see the changes taking place 300 miles away with no one anywhere nearby, and the data flowed back to land at the speed of light through the fiber-optic cable connected to Pacific City—and from there, to here on campus by the Internet, in milliseconds,” said John Delaney, a UW professor of oceanography who led the installation of the instruments as part of a larger effort sponsored by the National Science Foundation.
Delaney organized a workshop on campus in mid-April at which marine scientists discussed how this high-tech observatory would support their science. Then, just before midnight on April 23 until about noon the next day, the seismic activity went off the charts.
The gradually increasing rumblings of the mountain were documented over recent weeks by William Wilcock, a UW marine geophysicist who studies such systems.
During last week’s event, the earthquakes increased from hundreds per day to thousands per day, and the center of the volcanic crater dropped by about 6 feet (2 meters) over the course of 12 hours.
“The only way that could have happened was to have the magma move from beneath the caldera to some other location,” Delaney said, “which the earthquakes indicate is right along the edge of the caldera on the east side.”
The seismic activity was recorded by eight seismometers that measure shaking up to 200 times per second around the caldera and at the base of the 3,000-foot seamount. The height of the caldera was tracked by the bottom pressure tilt instrument, which measures the pressure of the water overhead and then removes the effect of tides and waves to calculate its position.
The depth instrument was developed by Bill Chadwick, an oceanographer at Oregon State University and the National Oceanic and Atmospheric Administration who has also been tracking the activity at Axial Volcano and predicted that the volcano would erupt in 2015.
The most recent eruptions were in 1998 and 2011.
The volcano is located about 300 miles west of Astoria, Oregon, on the Juan de Fuca Ridge, part of the globe-girdling mid-ocean ridge system—a continuous, 70,000 km (43,500 miles) long submarine volcanic mountain range stretching around the world like the strings on a baseball, and where about 70 percent of the planet’s volcanic activity occurs. The highly energetic Axial Seamount, Delaney said, is viewed by many scientists as being representative of the myriad processes operating continuously along the powerful subsea volcanic chain that is present in every ocean.
“This exciting sequence of events documented by the OOI-Cabled Array at Axial Seamount gives us an entirely new view of how our planet works,” said Richard Murray, division director for ocean sciences at the National Science Foundation. “Although the OOI-Cabled Array is not yet fully operational, even with these preliminary observations we can see how the power of innovative instrumentation has the potential to teach us new things about volcanism, earthquakes and other vitally important scientific phenomena.”
The full set of instruments in the deep-sea observatory is scheduled to come online this year. A first maintenance cruise leaves from the UW in early July, and will let researchers and students further explore the aftermath of the volcanic activity.
Did you feel that? Credit: Brian Collins/USFWS/flickr, CC BY
The recent earthquake in Nepal demonstrated yet again how difficult it is to reliably predict natural disasters. While we have a good knowledge of the various earthquakes zones on the planet, we have no way of knowing exactly when a big quake like the 7.8-magnitude event in Nepal will happen.
But we know that many animals seem able to sense the onset of such events. We could use powerful computers to monitor herds of animals and make use of their natural instincts to provide forewarning of natural disasters.
Immediately before an earthquake, herds of animals often start to behave strangely – for example suddenly leaving their homes to seek shelter. This could be because they detect small, fast-travelling waves or because they sense chemical changes in ground water from an impending earthquake.
Although there are possibilities here, we certainly need more studies – because it’s difficult to find statistically significant links between unusual animal behaviour and impending disasters. This is because natural disasters occur relatively rarely and it’s hard to reliably interpret animal behaviour after the fact. In fact, this uncertainty was quoted by the Chinese government after reports that zoo animals behaved strangely before the Wenchuan earthquake a few years ago.
There are areas where we know beyond doubt that animals have accurate detection ability, for example the way dogs can spot signs of cancer that we otherwise have difficulty recognising. We also know that by giving them animal-centred interfaces we can provide them the means to express what they detect, for example by hitting the right buttons according to their judgement.
This is an example of providing animals with accessible technology that supports their natural behaviour, while also translating their behaviour into something we can understand.
Of course, a key difference between a dog who is detecting cancer and a swarm of birds that is responding to the early signs of an imminent quake is in the numbers involved. We would expect an upcoming earthquake to affect many individuals at the same time, which would amplify the effect.
Collecting data in large quantities – while at the same time being able to recognise and filter background noise – requires efficient and elastic cloud computation. However, we already have technology that can do this, something we’ve previously suggested could be used to track the course of large numbers of aircraft.
So the bigger question is how to record data from large groups of animals, capitalising on advances in the Internet of Things, without affecting the welfare of the animals and without interfering with their natural behaviour.
Research has shown that putting sensors such as biotelemetric devices on animals can have seriously detrimental effects on their welfare, change their behaviour and, by doing so, invalidate whatever data is collected. Of course, trying to fit sensors to large numbers of animals for generation after generation would be highly impractical.
A better option would be to monitor changes in the animals’ behaviour around their habitats via ambient sensors such as motion detectors. The data could be used to automatically detect any deviation from normal behavioural patterns.
Herdsourcing
The “wisdom of crowds” has been put to use through the practice of crowdsourcing, where the internet is used to bring together a large, diverse range of users in order to undertake a certain task. For example, analysing Wikipedia documents, conducting citizen science projects, or generating cash through crowd-sourcing.
This is exactly that kind of concept we need to extend to animals in order to watch for collective changes in their behaviour. The technology of cloud computing, which can elastically scale to the amount of computation needed for such a project, is already commercially available.
The groundwork for the kind of system we need has been carried out as part of an ongoing security research programme. This project designs cloud-based software systems to recognise and adapt to changes that may have safety and security consequences.
Applied to the task of monitoring collective animal behaviour, the system could use sensors to detect big groups of animals in specific areas, monitor the speed and shape of their movement, or detect variations in their calls or cries. Of course, a major consideration would have to be to ensure the data is secure, so that for example it couldn’t be used to cause the animals harm (for example, through poaching).
We could apply approaches typically used for human-computer interfaces to animals; designing the means to do so for animals might shed light on how to predict earthquakes – not only that but it could show that there are plenty of other things we can find out from animals too, if only we can learn how to do it.
Note : The above story is based on materials provided by The Conversation. This story is published courtesy of The Conversation (under Creative Commons-Attribution/No derivatives).
Axial Seamount, an active underwater volcano located about 300 miles off the coast of Oregon and Washington, appears to be erupting – after two scientists had forecast that such an event would take place there in 2015.
Geologists Bill Chadwick of Oregon State University and Scott Nooner of the University of North Carolina Wilmington made their forecast last September during a public lecture and followed it up with blog posts and a reiteration of their forecast just last week at a scientific workshop.
They based their forecast on some of their previous research – funded by the National Science Foundation (NSF) and the National Oceanic and Atmospheric Administration (NOAA), which showed how the volcano inflates and deflates like a balloon in a repeatable pattern as it responds to magma being fed into the seamount.
Since last Friday, the region has experienced thousands of tiny earthquakes – a sign that magma is moving toward the surface – and the seafloor dropped by 2.4 meters, or nearly eight feet, also a sign of magma being withdrawn from a reservoir beneath the summit. Instrumentation recording the activity is part of the NSF-funded Ocean Observatories Initiative. William Wilcock of the University of Washington first observed the earthquakes.
“It isn’t clear yet whether the earthquakes and deflation at Axial are related to a full-blown eruption, or if it is only a large intrusion of magma that hasn’t quite reached the surface,” said Chadwick, who works out of OSU’s Hatfield Marine Science Center in Newport and also is affiliated with NOAA’s Pacific Marine Environmental Laboratory. “There are some hints that lava did erupt, but we may not know for sure until we can get out there with a ship.”
In any case, the researchers say, such an eruption is not a threat to coastal residents. The earthquakes at Axial Seamount are small and the seafloor movements gradual and thus cannot cause a tsunami.
“I have to say, I was having doubts about the forecast even the night before the activity started,” Chadwick admitted. “We didn’t have any real certainty that it would take place – it was more of a way to test our hypothesis that the pattern we have seen was repeatable and predictable.”
Axial Seamount provides scientists with an ideal laboratory, not only because of its close proximity to the Northwest coast, but for its unique structure.
“Because Axial is on very thin ocean crust, its ‘plumbing system’ is simpler than at most volcanoes on land that are often complicated by other factors related to having a thicker crust,” said Chadwick, who is an adjunct professor in OSU’s College of Earth, Ocean, and Atmospheric Sciences. “Thus Axial can give us insights into how volcano magma systems work – and how eruptions might be predicted.”
Axial Seamount last erupted in 2011 and that event was loosely forecast by Chadwick and Nooner, who had said in 2006 that the volcano would erupt before 2014. Since the 2011 eruption, additional research led to a refined forecast that the next eruption would be in 2015 based on the fact that the rate of inflation had increased by about 400 percent since the last eruption.
“We’ve learned that the supply rate of magma has a big influence on the time between eruptions,” Nooner said. “When the magma rate was lower, it took 13 years between eruptions. But now when the magma rate is high, it took only four years.”
Chadwick and Nooner are scheduled to go back to Axial in August to gather more data, but it may be possible for other researchers to visit the seamount on an expedition as early as May. They hope to confirm the eruption and, if so, measure the volume of lava involved.
Evidence that was key to the successful forecast came in the summer of 2014 via measurements taken by colleagues Dave Caress and Dave Clague of Monterey Bay Aquarium Research Institute and Mark Zumberge and Glenn Sasagawa of Scripps Oceanographic Institution. Those measurements showed the high rate of magma inflation was continuing.
The fourth largest gold producer in Africa is on target to reach 10 percent of its country’s Gross Domestic Product by 2025
Silica dust hazards in large gold mines have been well documented, but the situation is far worse in small-scale gold mining according to a new study.
The new research in the article “Silica Exposures in Artisanal Small-Scale Gold Mining in Tanzania and Implications for Tuberculosis Prevention” shows that exposures to silica are more than two hundred times greater in small-scale artisanal mines than in larger mines. Hundreds of thousands of miners have already come down with silicosis and rates of tuberculosis (TB) among miners in Africa are approximately 5-6 times higher than in the general population.
This first ever study to measure silica exposures in small-scale gold mining operations was published online in the Journal of Occupational and Environmental Health.
Researchers found that the average airborne crystalline silica levels in underground gold mining operations were 337 times greater than the recommended limit set by the U.S. National Institute of Occupational Safety and Health. Even miners working above ground had exposures that are four times the limit. Silica dust is a known cause of silicosis and lung cancer, and is strongly linked to TB and other lung diseases.
An estimated 15 million artisanal miners worldwide — many times more than are employed in formal sector mines — are working without any dust control measures.
Perry Gottesfeld, Executive Director of Occupational Knowledge International and the lead author of the study said, “Silica dust hazards are being ignored while thousands of miners die each year due to silicosis and the alarmingly high rates of TB in these mining communities.”
“A recent global treaty has emphasized reducing mercury exposures among these gold miners, while silica dust hazards are overlooked although they are likely to cause much more death and disease,” Gottesfeld added.
In sub-Saharan Africa, mining communities are experiencing an epidemic of TB due to the combination of silica exposures and higher background rates of people with HIV. These factors work together to multiply the risk.
“While we did the study in Tanzania, the risk for TB and silicosis is similar in artisanal mining around the world. Many times more people work in artisanal mining than in formal sector mines.” Gottesfeld added.
Globally, more than $3 billion a year is spent on diagnosing and treating TB.
Damian Andrew, an author of the study said that “The use of low cost methods to control airborne dust could significantly reduce exposures and the risk of TB and silicosis in these communities.”
“Simple measures including water misting would be an effective method to greatly reduce silica dust exposures,” he added.
The study also pointed out that more than half of all small-scale gold mining takes place in 18 of the 22 countries with the highest rates of TB. The World Health Organization (WHO) has prioritized these 18 countries as they account for 46% of all TB cases worldwide.
The authors conclude that ongoing efforts by governments and international aid agencies to address mercury hazards in small-scale gold mining should incorporate silica dust controls.
Reference:
Perry Gottesfeld, Damian Andrew, Jeffrey Dalhoff. Silica Exposures in Artisanal Small-Scale Gold Mining in Tanzania and Implications for Tuberculosis Prevention. Journal of Occupational and Environmental Hygiene, 2015; 00 DOI: 10.1080/15459624.2015.1029617
Note: The above story is based on materials provided by Taylor & Francis.
Illustration of a hot mantle plume “head” pancaked beneath the Indian Plate. The theory by Richards and his colleagues suggests that existing magma within this plume head was mobilized by strong seismic shaking from the Chicxulub asteroid impact, resulting in the largest of the Deccan Traps flood basalt eruptions. Credit: Mark Richards et al, UC Berkeley
The asteroid that slammed into the ocean off Mexico 66 million years ago and killed off the dinosaurs probably rang the Earth like a bell, triggering volcanic eruptions around the globe that may have contributed to the devastation, according to a team of University of California, Berkeley, geophysicists.
Specifically, the researchers argue that the impact likely triggered most of the immense eruptions of lava in India known as the Deccan Traps, explaining the “uncomfortably close” coincidence between the Deccan Traps eruptions and the impact, which has always cast doubt on the theory that the asteroid was the sole cause of the end-Cretaceous mass extinction.
“If you try to explain why the largest impact we know of in the last billion years happened within 100,000 years of these massive lava flows at Deccan … the chances of that occurring at random are minuscule,” said team leader Mark Richards, UC Berkeley professor of earth and planetary science. “It’s not a very credible coincidence.”
Richards and his colleagues marshal evidence for their theory that the impact reignited the Deccan flood lavas in a paper to be published in The Geological Society of America Bulletin, available online today (April 30) in advance of publication.
While the Deccan lava flows, which started before the impact but erupted for several hundred thousand years after re-ignition, probably spewed immense amounts of carbon dioxide and other noxious, climate-modifying gases into the atmosphere, it’s still unclear if this contributed to the demise of most of life on Earth at the end of the Age of Dinosaurs, Richards said.
“This connection between the impact and the Deccan lava flows is a great story and might even be true, but it doesn’t yet take us closer to understanding what actually killed the dinosaurs and the ‘forams,'” he said, referring to tiny sea creatures called foraminifera, many of which disappeared from the fossil record virtually overnight at the boundary between the Cretaceous and Tertiary periods, called the KT boundary. The disappearance of the landscape-dominating dinosaurs is widely credited with ushering in the age of mammals, eventually including humans.
He stresses that his proposal differs from an earlier hypothesis that the energy of the impact was focused around Earth to a spot directly opposite, or antipodal, to the impact, triggering the eruption of the Deccan Traps. The “antipodal focusing” theory died when the impact crater, called Chicxulub, was found off the Yucatán coast of Mexico, which is about 5,000 kilometers from the antipode of the Deccan traps.
Richards proposed in 1989 that plumes of hot rock, called “plume heads,” rise through Earth’s mantle every 20-30 million years and generate huge lava flows, called flood basalts, like the Deccan Traps. It struck him as more than coincidence that the last four of the six known mass extinctions of life occurred at the same time as one of these massive eruptions.
“Paul Renne’s group at Berkeley showed years ago that the Central Atlantic Magmatic Province is associated with the mass extinction at the Triassic/Jurassic boundary 200 million years ago, and the Siberian Traps are associated with the end Permian extinction 250 million years ago, and now we also know that a big volcanic eruption in China called the Emeishan Traps is associated with the end-Guadalupian extinction 260 million years ago,” Richards said. “Then you have the Deccan eruptions — including the largest mapped lava flows on Earth — occurring 66 million years ago coincident with the KT mass extinction. So what really happened at the KT boundary?”
Richards teamed up with experts in many areas to try to discover faults with his radical idea that the impact triggered the Deccan eruptions, but instead came up with supporting evidence. Renne, a professor in residence in the UC Berkeley Department of Earth and Planetary Science and director of the Berkeley Geochronology Center, re-dated the asteroid impact and mass extinction two years ago and found them essentially simultaneous, but also within approximately 100,000 years of the largest Deccan eruptions, referred to as the Wai subgroup flows, which produced about 70 percent of the lavas that now stretch across the Indian subcontinent from Mumbai to Kolkata.
Michael Manga, a professor in the same department, has shown over the past decade that large earthquakes — equivalent to Japan’s 9.0 Tohoku quake in 2011 — can trigger nearby volcanic eruptions. Richards calculates that the asteroid that created the Chicxulub crater might have generated the equivalent of a magnitude 9 or larger earthquake everywhere on Earth, sufficient to ignite the Deccan flood basalts and perhaps eruptions many places around the globe, including at mid-ocean ridges.
“It’s inconceivable that the impact could have melted a whole lot of rock away from the impact site itself, but if you had a system that already had magma and you gave it a little extra kick, it could produce a big eruption,” Manga said.
Similarly, Deccan lava from before the impact is chemically different from that after the impact, indicating a faster rise to the surface after the impact, while the pattern of dikes from which the supercharged lava flowed — “like cracks in a soufflé,” Renne said — are more randomly oriented post-impact.
“There is a profound break in the style of eruptions and the volume and composition of the eruptions,” said Renne. “The whole question is, ‘Is that discontinuity synchronous with the impact?'”
Reawakened volcanism
Richards, Renne and graduate student Courtney Sprain, along with Deccan volcanology experts Steven Self and Loÿc Vanderkluysen, visited India in April 2014 to obtain lava samples for dating, and noticed that there are pronounced weathering surfaces, or terraces, marking the onset of the huge Wai subgroup flows. Geological evidence suggests that these terraces may signal a period of quiescence in Deccan volcanism prior to the Chicxulub impact. Apparently never before noticed, these terraces are part of the western Ghats, a mountain chain named after the Hindu word for steps.
“This was an existing massive volcanic system that had been there probably several million years, and the impact gave this thing a shake and it mobilized a huge amount of magma over a short amount of time,” Richards said. “The beauty of this theory is that it is very testable, because it predicts that you should have the impact and the beginning of the extinction, and within 100,000 years or so you should have these massive eruptions coming out, which is about how long it might take for the magma to reach the surface.”
Reference:
Mark A. Richards, Walter Alvarez, Stephen Self, Leif Karlstrom, Paul R. Renne, Michael Manga, Courtney J. Sprain, Jan Smit, Loÿc Vanderkluysen, and Sally A. Gibson. Triggering of the largest Deccan eruptions by the Chicxulub impact. Geological Society of America Bulletin, April 30, 2015 DOI: 10.1130/B31167.1
Tropical marine ecosystems have been found to be most at risk from human impact. Credit: Andrew Baird
An international team of scientists has used the fossil record during the past 23 million years to predict which marine animals and ecosystems are at greatest risk of extinction from human impact.
In a paper published in the journal Science, the researchers found those animals and ecosystems most threatened are predominantly in the tropics.
“Marine species are under threat from human impacts, but knowledge of their vulnerabilities is limited,” says study co-author, Professor John Pandolfi from the ARC Centre of Excellence for Coral Reef Studies at the University of Queensland.
The researchers found that the predictors of extinction vulnerability, geographic range size and the type of organism, have remained consistent over the past 23 million years.
As such, they were able to use fossil records to assess the baseline extinction risk for marine animals, including sharks, whales and dolphins, as well as small sedentary organisms such as snails, clams and corals.
They then mapped the regions where those species with a high intrinsic risk are most affected today by human impact and climate change.
“Our goal was to diagnose which species are vulnerable in the modern world, using the past as a guide” says study lead author, Assistant Professor Seth Finnegan from the University of California Berkeley.
“We used these estimates to map natural extinction risk in modern oceans, and compare it with recent human pressures on the ocean such as fishing, and climate change to identify the areas most at risk,” says Professor Pandolfi.
“These regions are disproportionately in the tropics, raising the possibility that these ecosystems may be particularly vulnerable to future extinctions.”
The scientists say that identifying the regions and species at greatest risk means conservation efforts can be better targeted.
“We believe the past can inform the way we plan our conservation efforts. However there is a lot more work that needs to be done to understand the causes underlying these patterns and their policy implications,” says Asst. Professor, Seth Finnegan
Co-author, Dr Sean Anderson from Simon Fraser University in Burnaby, British Columbia adds, “It’s very difficult to detect extinctions in the modern oceans but fossils can help fill in the gaps.”
“Our findings can help prioritize areas and species that might be at greater risk of extinction and that might require extra attention, conservation or management — protecting vulnerable species in vulnerable places.”
Reference:
Seth Finnegan, Sean C. Anderson, Paul G. Harnik, Carl Simpson, Derek P. Tittensor, Jarrett E. Byrnes, Zoe V. Finkel, David R. Lindberg, Lee Hsiang Liow, Rowan Lockwood, Heike K. Lotze, Craig R. McClain, Jenny L. McGuire, Aaron O’Dea, and John M. Pandolfi. Paleontological baselines for evaluating extinction risk in the modern oceans. Science, April 2015 DOI: 10.1126/science.aaa6635
Princeton University researchers “weighed” Antarctica’s ice sheet using gravitational satellite data and found that from 2003 to 2014, the ice sheet lost 92 billion tons of ice per year. Credit: Image by Christopher Harig, Department of Geosciences
During the past decade, Antarctica’s massive ice sheet lost twice the amount of ice in its western portion compared with what it accumulated in the east, according to Princeton University researchers who came to one overall conclusion — the southern continent’s ice cap is melting ever faster.
The researchers “weighed” Antarctica’s ice sheet using gravitational satellite data and found that from 2003 to 2014, the ice sheet lost 92 billion tons of ice per year, the researchers report in the journal Earth and Planetary Science Letters. If stacked on the island of Manhattan, that amount of ice would be more than a mile high — more than five times the height of the Empire State Building.
The vast majority of that loss was from West Antarctica, which is the smaller of the continent’s two main regions and abuts the Antarctic Peninsula that winds up toward South America. Since 2008, ice loss from West Antarctica’s unstable glaciers doubled from an average annual loss of 121 billion tons of ice to twice that by 2014, the researchers found. The ice sheet on East Antarctica, the continent’s much larger and overall more stable region, thickened during that same time, but only accumulated half the amount of ice lost from the west, the researchers reported.
“We have a solution that is very solid, very detailed and unambiguous,” said co-author Frederik Simons, a Princeton associate professor of geosciences. “A decade of gravity analysis alone cannot force you to take a position on this ice loss being due to anthropogenic global warming. All we have done is take the balance of the ice on Antarctica and found that it is melting — there is no doubt. But with the rapidly accelerating rates at which the ice is melting, and in the light of all the other, well-publicized lines of evidence, most scientists would be hard pressed to find mechanisms that do not include human-made climate change.”
Compared to other types of data, the Princeton study shows that ice is melting from West Antarctica at a far greater rate than was previously known and that the western ice sheet is much more unstable compared to other regions of the continent, said first author Christopher Harig, a Princeton postdoctoral research associate in geosciences. Overall, ice-loss rates from all of Antarctica increased by 6 billion tons per year each year during the 11-year period the researchers examined. The melting rate from West Antarctica, however, grew by 18 billion tons per year every year, Harig and Simons found. Accelerations in ice loss are measured in tons per year, per year, or tons per year squared.
Of most concern, Harig said, is that this massive and accelerating loss occurred along West Antarctica’s Amundsen Sea, particularly Pine Island and the Thwaites Glacier, where heavy losses had already been recorded. An iceberg more than 2,000 square miles in size broke off from the Thwaites Glacier in 2002.
In Antarctica, it’s the ocean currents rather than air temperatures that melt the ice, and melted land ice contributes to higher sea levels in a way that melting icebergs don’t, Harig said. As the ocean warms, floating ice shelves melt and can no longer hold back the land ice.
“The fact that West Antarctic ice-melt is still accelerating is a big deal because it’s increasing its contribution to sea-level rise,” Harig said. “It really has potential to be a runaway problem. It has come to the point that if we continue losing mass in those areas, the loss can generate a self-reinforcing feedback whereby we will be losing more and more ice, ultimately raising sea levels by tens of feet.”
The Princeton study differs from existing approaches to measuring Antarctic ice loss in that it derives from the only satellite data that measure the mass of ice rather than its volume, which is more typical, Simons explained. He and Harig included monthly data from GRACE, or the Gravity Recovery and Climate Experiment, a dual-satellite joint mission between NASA and the German Aerospace Center. GRACE measures gravity changes to determine the time-variable behavior of various components in the Earth’s mass system such as ocean currents, earthquake-induced changes and melting ice. Launched in 2002, the GRACE satellites are expected to be retired by 2016 with the first of two anticipated replacement missions scheduled for 2017.
While the volume of an ice sheet — or how much space it takes up — is also crucial information, it can change without affecting the amount of ice that is present, Simons explained. Snow and ice, for instance, compact under their own weight so that to the lasers that are bounced off the ice’s surface to determine volume, there appears to be a reduction in the amount of ice, Simons said. Mass or weight, on the other hand, changes when ice is actually redistributed and lost.
Simons equated the difference between measuring ice volume and mass to a person weighing himself by only looking in the mirror instead of standing on a scale.
“You shouldn’t only look at the ice volume — you should also weigh it to find the mass changes,” Simons said. “But there isn’t going to be a whole lot of research of this type coming up because the GRACE satellites are on their last legs. This could be the last statement of this kind on these kinds of data for a long time. There may be a significant data gap during which the only monitoring available will not be by ‘weighing’ but by ‘looking’ via laser or radar altimetry, photogrammetry or field studies.”
Harig and Simons developed a unique data-analysis method that allowed them to separate GRACE data by specific Antarctic regions. Because the ice sheet behaves differently in different areas, a continent-wide view would provide a general sense of how all of the ice mass, taken together, has changed, but exclude finer-scale geographical detail and temporal fluctuations. They recently published a paper about their computational methods in the magazine EOS, Transactions of the American Geophysical Union, and used a similar method for a 2012 paper published in the Proceedings of the National Academy of Sciences that revealed sharper-than-ever details about Greenland’s accelerating loss of its massive ice sheet.
Robert Kopp, a Rutgers University associate professor of earth and planetary sciences and associate director of the Rutgers Energy Institute, said the analysis method Harig and Simons developed allowed them to capture a view of regional Antarctic ice loss “more accurately than previous approaches.” Beyond the recent paper, Harig and Simons’ method could be important for testing models of Antarctic ice-sheet stability developed by other researchers, he said.
“The notable feature of this research is the power of their method to resolve regions geographically in gravity data,” Kopp said. “I expect that [their] technique will be an important part of monitoring future changes in the ice sheet and testing such models.”
Reference:
Christopher Harig, Frederik J. Simons. Accelerated West Antarctic ice mass loss continues to outpace East Antarctic gains. Earth and Planetary Science Letters, 2015; 415: 134 DOI: 10.1016/j.epsl.2015.01.029
Note: The above story is based on materials provided by Princeton University. The original article was written by Morgan Kelly.
A team of Ludwig-Maximilians-Universitaet (LMU) in Munich has identified the first fossil specimens of a major group of killifishes that is widely distributed in freshwater habitats today. The 6-million-year-old material sheds new light on the evolution of the bony fishes.
Killifish are true survivors. These colorful little fish are perfectly adapted to the demands of their ephemeral habitats. They spend their short lives in temporary freshwater pools that form during the rainy season, and owe their long-term survival to the fact that their eggs are resistant to desiccation. Although they are a species-rich group, and are widely distributed in the tropics and subtropics, their fossil record is sparse. But now LMU palaeontologists Professor Bettina Reichenbacher and Melanie Altner have identified the first fossil representatives of one of the two extant suborders of killifish. “The specimens are exceptionally well preserved, date from about 6 million years ago, and were discovered in Kenya by French palaeoanthropologists,” says Reichenbacher. “Our studies have now shown that they are members of a previously unknown genus that is now extinct, which we have named Kenyaichthys – the fish from Kenya.”
The fossils originate from a site located in the Tugen Hills, which lie in the Eastern arm of the East African Rift Valley. During the Late Miocene – about six million years ago – the site formed part of a lake, and the newly described specimens, each 2 to 4 cm long, were preserved in the sediment beds that accumulated on the lake bottom. “The sample comprises a total of 169 individuals, and 77 of these are complete,” says Altner. The anatomical details discernible in the impressions left in the sediments enabled the two researchers to conclusively identify all of these individuals as killifishes. “Analysis of the structures of the tailfin, the pelvic fins and the bones in the skull, in particular, yielded crucial information that convinced us that this material constituted the first fossils attributable to the killifish Suborder Aplocheiloidei. This group also encompasses modern African killifishes, such as Pachypanchax from Madagascar, the striped panchaxes of Southeast Asia and the rivulids of South America,” Altner explains.
In addition to the fossil aplocheiloids, only a few other freshwater forms were found at the site. Reichenbacher and Altner assume that the prevailing environmental conditions were too extreme for less specialized species. During the Late Miocene, the climate got drier and extensive areas of savannah developed. “We believe that, like modern killifish species, Kenyaichthys was well equipped to survive long periods of drought, and could cope better with such conditions than other species of fish,” says Reichenbacher.
A unique combination of traits
Since many killifish species are short-lived they are used to study aging processes. But the group is also of interest to evolutionary biologists because they offer useful models for the study of speciation – and in this context some of the characters displayed by Kenyaichthys are especially intriguing: “Our fossils exhibit morphological traits that are found in extant African species of killifish. But they also possess one specific trait that is typical for contemporary rivulids from South America. This combination is very unusual, and may indicate that Kenyaichthys is closely related to forms that are now restricted to South America. Alternatively, this particular character may have been lost in the lineage that gave rise to modern African aprocheiloids,” Altner explains.
Furthermore, many features of the new fossils – including elements of the tailfin and the dorsal fins, and the relative sizes of the different body parts – vary markedly from one individual to the next. As the closest surviving relatives of Kenyaichthys do not display such a wide range of variability, the fossil material from the Tugen Hills appears to document a particularly fascinating evolutionary process – the diversification of a so-called species flock. The term ‘species flock’ refers to a group of closely related species that have evolved from a single progenitor species in an isolated population and developed distinct specializations that enable them to coexist. Darwin’s finches, which occupy different ecological niches on the Galapagos, are perhaps the best known example of a species flock. “So, this is an exciting find in many respects, which provides wholly new insights into the evolutionary history of the killifishes and their relatives,” says Reichenbacher.
Reference:
“Kenyaichthyidae fam. nov. and Kenyaichthys gen. nov. – First Record of a Fossil Aplocheiloid Killifish (Teleostei, Cyprinodontiformes).” PLoS ONE 10(4): e0123056. DOI: 10.1371/journal.pone.0123056
In their article for Lithosphere on 12 March, authors Kristin Morell and colleagues write, “The ∼700-km-long ‘central seismic gap’ is the most prominent segment of the Himalayan front not to have ruptured in a major earthquake during the last 200-500 years. This prolonged seismic quiescence has led to the proposition that this region, with a population of more 10 million, is overdue for a great earthquake. Despite the region’s recognized seismic risk, the geometry of faults likely to host large earthquakes remains poorly understood.”
A little more than a month on, the area experience a magnitude 7.8 earthquake, centered in Nepal (25 Apr. 2015).
In their study, Morell and colleagues use a series of complementary geomorphic and erosion rate data to define the ramp-flat geometry of the active detachment fault that is likely to host a large earthquake within the hinterland of the northwest Himalaya. Their analysis indicates that this detachment is sufficiently large to host another great earthquake in the western half of the central Himalayan seismic gap.
Specifically, their data sets point to a distinctive physiographic transition at the base of the high Himalaya in the state of Uttarakhand, India, characterized by abrupt strike-normal increases in channel steepness and a tenfold increase in erosion rates.
When combined with previously published geophysical imaging and seismicity data sets, Morell and colleagues interpret the observed spatial distribution of erosion rates and channel steepness to reflect the landscape response to spatially variable rock uplift due to a structurally coherent ramp-flat system of the Main Himalayan Thrust. They write, “Although it remains unresolved whether the kinematics of the Main Himalayan Thrust ramp involve an emergent fault or duplex, the landscape and erosion rate patterns suggest that the décollement beneath the state of Uttarakhand provides a sufficiently large and coherent fault segment capable of hosting a great earthquake.”
In conclusion, they note, “While this hypothesis remains speculative, it is supported by independent records of historical seismicity.”
*Photo Caption:
Figure 1. (A) Date and rupture patches for large historical Himalayan earthquakes (Rajendran and Rajendran, 2005; Kumar et al., 2006) with reference to the Uttarakhand region of the central seismic gap, and the physiographic transition 2 of Uttarakhand (UPT2 ) and Nepal (NPT2 ) (Wobus et al., 2006a). (B) Simplified geologic map for area shown in A (Célérier et al., 2009a; Webb et al., 2011). Focal mechanisms of all earthquakes within the recording period (Mw 5-7) are shown with location as white circle. Earthquake locations are based on Ni and Baranzangi (1984) and the National Earthquake Information Center (NEIC) catalog (earthquake.usgs.gov). Focal mechanisms are based on Ni and Baranzangi (1984) or the Global Centroid-Moment-Tensor (CMT) catalog (globalcmt.org). STD–South Tibetan Detachment; THS–Tethyan Himalayan Sequence; MCT–Main Central Thrust; GHS–Greater Himalayan Sequence; LHS–Lesser Himalayan Sequence; MBT–Main Boundary Thrust; MFT–Main Frontal Thrust.
Reference:
Geomorphology reveals active decollement geometry in the central Himalayan seismic gap
K.D. Morell et al., University of Melbourne, Melbourne, Victoria, Australia. Published online ahead of print on 12 Mar. 2015; DOI: 10.1130/L407.1.
Ocean areas predicted to be at high risk of extinction (red) are overlaid with areas most impacted by humans (black outline) and regions experiencing a high rate of climate change (crosshatch). Credit: Finnegan et al, Science.
A detailed study of marine animals that died out over the past 23 million years can help identify which animals and ocean ecosystems may be most at risk of extinction today, according to an international team of paleontologists and ecologists.
In a paper to be published in the May 1 issue of the journal Science, researchers from the University of California, Berkeley, and other institutions report that worldwide patterns of extinction remained remarkably similar over this period, with the same groups of animals showing similar rates of extinction throughout and with a consistent set of characteristics associated with elevated extinction risk.
The researchers then used these past global extinction patterns as a baseline to predict which ocean areas and marine organisms would be most at risk today without the added threat of human-caused habitat destruction, overfishing, pollution and ocean acidification.
Finally, the authors combined this natural or ‘intrinsic’ extinction risk with current threats from humans and climate change to obtain a global map of potential future hotspots of extinction risk.
“Our goal was to diagnose which species are vulnerable in the modern world, using the past as a guide,” said lead author Seth Finnegan, an assistant professor of integrative biology at UC Berkeley. “We believe the past can inform the way we plan our conservation efforts. However, there is a lot more work that needs to be done to understand the causes underlying these patterns and their policy implications.”
“It’s very difficult to detect extinctions in the modern oceans, but fossils can help fill in the gaps,” added co-author and conservation biologist Sean Anderson, a postdoctoral researcher at Simon Fraser University in Burnaby, British Columbia. “Our findings can help prioritize areas and species that might be at greater risk of extinction and that might require extra attention, conservation or management.”
The study found that animals with small geographic ranges are most at risk of extinction, Finnegan said. In addition, some groups tend to be more extinction-prone than others. For example, in the fossil record, whales, dolphins and seals show higher risk of extinction than sharks or invertebrates such as corals. Clams and mussels — so-called bivalves — had about one-tenth the extinction risk of mammals.
The authors used these patterns from the fossil record to assess the natural extinction risk of animals living in the oceans today. Comparing these patterns with areas where human activities such as fishing impact the oceans revealed areas that may be particularly sensitive. These areas included high- biodiversity regions of the tropics such as the Indo-Pacific and the Caribbean, as well as regions such as Antarctica that harbor many unique species.
“The implications of these patterns for the future of coastal marine ecosystems will depend on how natural risk and current threats interact,” said co-author Paul Harnik, an assistant professor of geosciences at Franklin and Marshall College in Lancaster, Pennsylvania. “”By understanding these patterns in the past, we hope to provide a framework for understanding global change.”
Bridging the gap
The analysis grew out of a series of meetings at the National Evolutionary Synthesis Center in Durham, North Carolina, which is funded by the National Science Foundation. The team agreed on the need to bridge the gap between the fossil record of marine animal extinction and what modern-day biologists are finding as they explore living ocean ecosystems.
The group focused on the past 23 million years when the planet looked largely the same as today: The continents were arranged similarly, and most of the same major taxonomic groups, from whales and seals to clams, snails and sea urchins, existed. However, this time interval encompassed dramatic changes in Earth’s climate. The group determined that patterns of extinction risk were consistent despite this variability — suggesting that the fossil record can provide a valuable pre-human baseline for considering current threats to marine biodiversity.
“Climate change and human activities are impacting groups of animals that have a long history, and studying that history can help us condition our expectations for how they might respond today,” Finnegan said.
Airports use de-icing agents during the winter. These chemicals have a negative impact on groundwater quality, according to a new study of geoscientists from the Friedrich Schiller University Jena. Credit: Jan-Peter Kasper
Jena (Germany) Spring has arrived in Europe with mild temperatures and sunshine. Where just a few weeks ago the ground was frozen and partly covered in snow and ice, it is now thawing. This doesn’t only have an impact on the flora and fauna. Thawing results in soil and the groundwater at airports being impacted by chemicals, which are contained in melt water. The reason: Airports have to use de-icing agents during the winter, which end up on unpaved areas and infiltrate into the soils during snowmelt.
“Admittedly, airport operators in EU-countries are compelled to sustain a good condition of the groundwater or at least to avoid detrimental concentrations of pollutants in the groundwater,” says PD Dr. Markus Wehrer from the Friedrich Schiller University Jena (Germany). “However, it is common practice that along the runways huge amounts of de-icing fluids infiltrate into the ground,” the Hydrogeologist adds. It does indeed make sense to use the natural self cleaning capacities of the soil. However, the de-icing chemicals have a negative impact on groundwater quality and the functions of the soil. This was shown in a new study of a team of researchers around Prof. Dr. Kai Uwe Totsche at the Jena Chair of Hydrogeology.
In the science magazine “Environmental Science and Pollution Research” the scientists of the University Jena wrote that chemicals like propylene glycol and potassium formate are being degraded by micro-organisms living in the soil and therefore don’t get into the groundwater – at least not straight away (DOI: 10.1007/s11356-014-3506-3). “On the other hand, heavy pollution through these substances leads to a dramatic decrease of oxygen content in soils and groundwater,” Heidi Lissner, the first author of the study explains: This is because the microbes use oxygen to degrade the pollutants. “The more of these substances they have to metabolize, the more oxygen they use for this,” says the geoscientist, who developed the results – which are now published in the study – within the framework of her PhD thesis. As a consequence iron and manganese oxides, which stabilize the intergranular cement of the structure of the soil, dissolve.
For their study the Jena team of researchers analyzed the soil around the airport of the Norwegian capital Oslo. There, every winter about 1,000-1,500 tons of de-icing agents are used. “At the same time, the airport is situated directly next to the largest superficial aquifer in Norway, the Romerike-Aquifer,” explains Dr. Wehrer, who supervised Heidi Lissner’s work together with Prof. Dr. Totsche. The geoscientists took soil core samples close to the runway of the airport and examined them. “We wanted to find out, how the de-icing agents affect the condition of the soil and the percolating water,” Heidi Lissner explains. In order to do so, the young scientist loaded soil cores with water that contained de-icing chemicals and thus simulated a “thawing event”. She collected the seepage water after it passed through the soil cores, followed by an examination for de-icing chemicals as well as the oxygen content and additional parameters.
According to the Jena scientists, their exemplary results can be transferred to the situation at other airports. “Chemicals for de-icing aircrafts as well as runways are used wherever there is snow and ice in winter,” Dr. Wehrer says. He stresses that, additionally, measures to reduce the oxygen content in the soil around airports could be deducted from the new scientific results. Apart from installing specific areas, which allow the thawing water to seep away in a controlled manner, a controlled use of bacteria in the soil, which are specialized in the degradation of these chemicals, is conceivable. This requires an additionally improved oxygen supply in the soil. Also, alternative substances, which can be used for the degradation of pollutants similar to the way in which oxygen works, may be supplied. Moreover, the texture of the soil could be shaped in a way that delays the seepage of the polluted soil water. Through a longer interval, which is then available for the degradation of the substances, a lack of oxygen could be avoided, because atmospheric oxygen is transferred slowly but continuously into the soil.
Reference:
Lissner H. et al. Constraints of propylene glycol degradation at low temperatures and saturated flow conditions. Environ Sci Pollut Res (2015) 22:3158-3174, DOI: 10.1007/s11356-014-3506-3
Exposures of Pleistocene sediments containing marine fossils in Jamaica. Data from fossil localities around the globe were analyzed by Finnegan and coauthors in their study of extinction risk in the oceans. Credit: Aaron O’Dea
The fossil record helps to predict which kinds of animals are more likely to go extinct. When combined with information about hotspots of human impacts and climate-change predictions, Smithsonian scientists and colleagues pinpoint animal groups and geographic areas of highest concern for marine conservation in the May 1 issue of Science magazine.
“Just as some groups of people are more prone to health problems like diabetes or heart disease, we can tell from the fossil record which groups of animals are naturally more likely to go extinct,” said Aaron O’Dea, paleontologist at the Smithsonian Tropical Research Institute. “Our calculations suggest that the animal’s geographic range and the group they belong to are the best predictors of extinction risk,” said Carl Simpson, coauthor and post-doctoral researcher at the Smithsonian’s National Museum of Natural History. The study reveals that marine mammals, sharks and corals are animals that have naturally high risks of extinction.
Plotting this data globally, the study suggests that the Tropical West Atlantic and Tropical West Pacific are at potentially greatest risk to naturally high levels of extinction. Unfortunately these areas are also predicted to experience the fastest rates of climate change and greatest future human impact, such as habitat destruction, overfishing and pollution.
“There is a lot to be refined, but life in tropical seas appears to be naturally prone to extinction and is under increasing stress from human activities,” O’Dea said. “It’s a daunting combination that suggests the great diversity of tropical seas might need much greater protection than it has previously received.”
Reference:
Finnegan, S., Anderson, S.C., Harnik, P.G., Simpson, C., Tittensor, D.P., Byrnes, J.E., Finkel, Z.V., Lindberg, D.R., Liow, L.H., Lockwood, R., Lotze, H.K., McClain, C.M., McGuire, J.L., O’Dea, A. and Pandolfi, J.M., 2015. Paleontological baselines for evaluating extinction risk in the modern oceans. Science
Artist’s impression of the new dinosaur Yi qi. Credit: Dinostar Co. Ltd
The discovery of a pigeon-sized dinosaur with bat-like wings has exposed bizarre twists in the early evolution of birds, said scientists in China Wednesday whose conclusions were immediately challenged.
Named Yi qi, for “Strange Wing” in Mandarin, the creature was an odd and unexpected addition to a long list of failed evolutionary experiments in flight—having sported wings of membrane rather than feathers, they said.
“It is definitely an example showing how much experimentation occurred,” said palaeontologist Xu Xing of the Chinese Academy of Sciences in Beijing, who co-authored a study in the journal Nature.
“Close to the origin of birds (from dinosaurs)… many lineages tried in a different way to get into the air, but finally only one group succeeded.”
Xu and his team described Yi qi as “bizarre” in the title of their study, an unusual adjective in the dry, scientific world of science publishing.
Yi qi was not a direct ancestor of birds, but a close relative from an extinct line.
Bearing the shortest name ever given to a dinosaur, Yi qi belonged to a family of tiny creatures called Scansoriopterygids, which had feathers and exceptionally long finger-like digits that may have been used for climbing trees or catching insects
Known only from fossils found in China, Scansoriopterygids were closely related to primitive bird types like Archaeopteryx, considered a transitional species between non-avian dinosaurs and birds.
But they were not thought to have been fliers. Until now.
Yi qi, the newest addition to the group, weighed about 380 grammes (13.4 ounces) as an adult, and had tiny teeth set in a four centimetre-long (1.6-inch) skull.
It had feathers considered too flimsy to be useful in flight.
But what really sets Yi qi apart is a bony rod, about 13 centimetres (five inches) long, jutting from each wrist.
“To be honest it took a long time for us to figure out” what it was, Xu said in a podcast recorded by Nature.
Then eureka! While never before seen in dinosaurs, the team realised the feature is similar to one sported by modern-day airborne mammals—think bats and flying squirrels.
“We realised that it is a structure very, very important finally for flight,” said Xu.
Sure enough, the team also found remnants of “membranous tissue” preserved with the bones.
Yi qi is known from a sole fossil discovered by a farmer near Beijing in 160-million-year-old rock from the Jurassic period.
Nothing below the ribcage was preserved, so the critter’s pelvis, hind legs and tail had to be surmised from what is known of other Scansoriopterygids.
Not everyone is convinced by the role ascribed to the bony protrusions, each curved at either end.
“Things have just gone from the strange to the bizarre,” University of California biologist Kevin Padian said of the findings in a comment carried by Nature.
“To fly actively, an animal must be able to execute a flight stroke that can generate a vortex wake that propels it forward,” he said.
“No evidence presented so far suggest that Yi qi had this ability,” added Padian, and suggested “we can shelve the possibility that this dinosaur flapped”.
As for gliding, the jury is out, he said, given that little is known of the tiny animal’s posterior, and thus its centre of gravity.
“We are left in a quandary: an animal with a strange structure that looks as if it could have been used in flight, borne by an animal that otherwise shows no such tendencies,” Padian wrote.
For Nature editor Henry Gee, a palaeontologist and evolutionary biologist, a feathered dinosaur with a wing membrane “is not something anyone would ever have expected to find”, adding the paper “will cause a great deal of flap, dare one say.”
Xu insisted the evidence “supports the inference that it is a gliding or flying animal.”
“To be honest, I just couldn’t imagine if this structure were not used in flight what else it could function in,” he said.
“But of course, it is open. I definitely welcome other scientists to do some analyses and have their opinion of this structure.”
Video
Reference:
A bizarre Jurassic maniraptoran theropod with preserved evidence of membranous wings, DOI: 10.1038/nature14423
Note: Note : The above story is based on materials provided by AFP.
Combining two Sentinel-1A radar scans from 17 and 29 April 2015, this interferogram shows changes on the ground that occurred during the 25 April earthquake that struck Nepal. An overall area of 120×100 km has moved – half of that uplifted and the other half, north of Kathmandu subsided. Vertical accuracy is a few cm. Credit: Copernicus data (2015)/ESA/Norut/PPO.labs/COMET–ESA SEOM INSARAP study
On 25 April, a 7.8-magnitude earthquake struck Nepal, claiming over 5000 lives and affecting millions of people. Satellite images are being used to support emergency aid organisations, while geo-scientists are using satellite measurements to analyse the effects of the earthquake on the land.
Radar imagery from the Sentinel-1A satellite shows that the maximum land deformation is only 17 km from Nepal’s capital, Kathmandu, which explains the extremely high damage experienced in this area.
By combining Sentinel-1A imagery acquired before and after the quake, changes on the ground that occurred between the two acquisition dates lead to rainbow-coloured interference patterns in the combined image, known as an ‘interferogram’, enabling scientists to quantify the ground movement.
Sentinel-1A’s swath width of 250 km over land surfaces has allowed for an unprecedented area size to be analysed from a single scan. The entire area will be covered under the same geometry every 12 days, allowing for the wider region to be regularly monitored and fully analysed for land deformation with the powerful ‘interferometry’ technique.
Products ensuring a full coverage of the affected area prior to the earthquake were available to all scientists under the Copernicus free and open data policy, and will continue to be available.
Sentinel-1A is the first satellite for the Copernicus environment-monitoring programme led by the European Commission. Its all-weather, day-or-night radar imagery is particularly suited to support impact assessment for many types of geohazards. The satellite is planned to provide systematic observations of tectonic and volcanic areas at global level.
Imagery from the Sentinels and other Copernicus contributing missions are coordinated by ESA to be used by the Copernicus Emergency Management Service (EMS), which supports all phases of the emergency management cycle.
The Copernicus EMS was activated on the day the earthquake struck, prompting ESA to begin collecting satellite imagery, which is being made available to support relief efforts.
In parallel, the International Charter Space and Major Disasters was activated by India, China and the UN. Partner Agencies of this initiative have been providing data and products over the area to relief organisations.
Under the Copernicus Emergency Management Service, ESA has been coordinating the collection of optical satellite imagery following the earthquake that struck Nepal on 25 April 2015. The satellite imagery is then used to create maps to support relief efforts, such as this ‘grading map’ of Kathmandu showing topographic features and crisis information. The map is based on imagery from the WorldView-3 satellite acquired on 28 April. Credit: DigitalGlobe/European Commission
High discharge and suspended sediment concentration during the second highest discharge event of the 2014 monsoon season, in the Kali Gandaki River at Tatopani in Nepal. Credit: Christoff Andermann, GFZ
In these days, it was again tragically demonstrated that the Himalayas are one of the most active geodynamic regions of the world. Landslides belong to the most important geohazards. Besides earthquakes they are triggered mainly by strong rainfall events. A team of scientists from Nepal, Switzerland and Germany was now able to show how erosion processes caused by the monsoon are mirrored in the sediment load of a river crossing the Himalaya.
The geoscientists used data from two stations along the Kali Gandaki, a river that traverses the Himalaya from North to South through the deepest valley on Earth. The Kali Gandaki flows between the peaks of the Annapurna and Dhaulagiri, both reaching above 8000 m in height, and joins the Ganges in India. One of the stations is located at the transition from the Tibetan plateau and the high Himalayas, the other one lies in the middle Himalaya, south of the high peaks.
The size of particles transported transported by the river ranges from fine dust to boulders. Important information about erosion mechanisms in the river catchment can be obtained from these sizes, since they are determined by the rocks that are supplied from hillslopes and moved into the river by landsliding.
“For the first time we were able to obtain a time series of measurements from two different locations along a single river”, says Christoff Andermann from the GFZ German Research Centre for Geosciences. “In this way we can differentiate between sediments: which material came from Tibet and were transported through the Himalaya, and which were produced in the Himalayas themselves?” The key to the answer for these questions lies in the size of the transported particles, the grain size.
Although the Tibetan material always shows the same size, the Himalayan sediment is bigger during the summer monsoon. GFZ scientist Andermann: “The comparison with the timing of landslides shows the relationship between the erosion of the mountains and the monsoon, since most landslides are caused by heavy rain.”
The study raises interesting questions about geo-archives: the erosional history of mountains can be reconstructed from their deposits. However, sediments in the Gulf of Bengal, commonly associated with the Himalaya, contain mainly fine material. The coarse material of the Himalaya seem to have been lost somewhere on the way to the ocean. Thus, the question arises where the sediments in the Gulf of Bengal originated from and what stories they can tell.
Reference:
Martin Struck, Christoff Andermann, Niels Hovius, Oliver Korup, Jens M. Turowski, Raj Bista, Hari P. Pandit and Ranjan K. Dahal: “Monsoonal hillslope processes determine grain size-specific suspended sediment fluxes in a trans-Himalayan river”, Geophysical Research Letters, Vol. 42, Nr. 7, April 2015, pp. 2302-2308 DOI: 10.1002/2015GL063360
This image shows the skulls of the different species the researchers studied along with biomechanical profiles, which were made by mapping each animal’s bite force against skull stiffness. They found that ancestry has a strong influence on the models, with closely related animals like leopards and mongooses grouping together, but also that predications about diet can be made based on the shape of the individual biomechanical profiles. Credit: Copyright AMNH/Z.-J. Tseng
When paleontologists put together a life history for a long-extinct animal, they try to understand its diet by looking at modern animals with similar skull shapes and tooth patterns. But this practice is far from foolproof. New modeling and tests based on living species conducted by scientists at the American Museum of Natural History show that the link between animal diets and skull biomechanics is complex, with a stronger influence from ancestry than previously thought.
“Traditionally, when we looked at a fossilized skull with pointy piercing teeth and sharp slicing blades, we assumed that it was primarily a meat eater, but that simplistic line of thinking doesn’t always hold true,” said John J. Flynn, the Museum’s Frick Curator of Fossil Mammals and a co-author on the new work published today in the journal PLOS ONE. “We’ve found that diet can be linked to a number of factors—skull size, biomechanical attributes, and often, most importantly, the species’ position in the tree of life.”
Dr. Flynn and Z. Jack Tseng, a National Science Foundation and Frick Postdoctoral Fellow in the Museum’s Division of Paleontology, looked at the relationship between skull shape and function of five different modern carnivore species: “hypercarnivores” like wolves and leopards whose diet is more than 70 percent meat and more omnivorous “generalists” such as mongooses, skunks, and raccoons. The initial modeling, which mapped bite force against the stiffness of the animal’s skull, yielded a surprise.
“Animals with the same diets and biomechanical demands, like wolves and leopards—both hypercarnivores—were not linking together,” Dr. Tseng said. “Instead, we saw a strong signal driven mostly by ancestry, where, for example, the leopard and the mongoose bind together because they’re more closely related in an evolutionary context, although they have very different dietary preferences and feeding strategies.”
But once Tseng and Flynn accounted for the strong effects of ancestry and skull size on the models, hypercarnivores and generalists still could be distinguished based on biomechanics, in particular by looking at where along the tooth row the skull is strongest. The skulls of heavy meat eaters tend to be stiff near the front teeth for hunting, and the back teeth for crushing bones and slicing meat. In contrast, generalist skulls get slightly stiffer from the front row of teeth to the back row.
With an improved shape-function computer model in hand, Flynn and Tseng applied the research to a pair of extinct species: Thinocyon velox, a predatory mammal that was part of the now-extinct Creodont group, and Oodectes herpestoides, an early fossil predecessor of modern carnivores. The results suggested that T. velox likely had a unique hypercarnivorous feeding style that emphasized prey capture with its front teeth and powerful slicing and crushing with its back teeth, while O. herpestoides was a generalist.
“Beyond feeding adaptations of extinct species, we also want to decipher how adaptations evolved using reconstructed ancestors of living and fossil forms,” Tseng said. “We are applying similar types of skull shape and biomechanical analyses to reconstructed hypothetical ancestor skulls of Carnivora and their relatives to map out and better understand the long history of feeding adaptation of living top predators.”
Reference:
Zhijie Jack Tseng , John J. Flynn. Are Cranial Biomechanical Simulation Data Linked to Known Diets in Extant Taxa? A Method for Applying Diet-Biomechanics Linkage Models to Infer Feeding Capability of Extinct Species. PLoS One, 2015 DOI: 10.1371/journal.pone.0124020
Erik Gulbranson, a visiting professor at the University of Wisconsin-Milwaukee, working in the Antarctic. Credit: Peter Rejcek, NSF
Erik Gulbranson, a visiting professor at the University of Wisconsin-Milwaukee, trudges up a steep ridge overlooking his field camp of mountain tents and pyramid-shaped Scott tents in Antarctica’s McMurdo Dry Valleys. A brief hike nearly to the top of a shorter ridge ends at the quarry, where picks and hammers have chopped out a ledge of sorts in the slate-grey hillside.
Sometime about 220 million years ago, a meandering stream flowed here and plants grew along its banks. Something, as yet unknown, caused sediment to flood the area rapidly, which helped preserve the plants. Gulbranson splits open a grey slab of siltstone in the quarry to reveal amazingly well-preserved Triassic plant fossils, as if the leaves and stems had been freshly pressed into the rock only yesterday.
“It’s a mixture of plants that don’t exist anymore,” he says, “but we have some plants in these fossil ecosystems that we might know today, like ginkgo.”
On the one end are fossils from an extinct genus of fork-leaved seed ferns called Dicroidium that dominated during the Triassic, a geologic period that lasted from about 252 to 200 million years ago. Other plants frozen in time on this remote hillside include species in the extant cycad family, which today favor subtropical and tropical climates.
Even better are the fossilized specimens no one can yet identify.
“They’re brand new to Antarctica,” said Gulbranson, who is co-principal investigator on a project investigating the evolution of ancient plants in Antarctica and the high-latitude environments in which they grew.
Also new to Antarctica: A Triassic-age fossil forest of 37 tree stumps, located less than a couple of kilometers almost directly south from the quarry. These were discovered about a week after Gulbranson and a team of paleontology experts in plants, fungi and other areas arrived at Allan Hills by helicopter and Twin Otter aircraft.
It is only the second fossil forest from the Triassic ever found in Antarctica. It’s about a third the size of a site in Gordon Valley near the Beardmore Glacier in the Transantarctic Mountains. The Gordon Valley fossil forest, discovered in 2003, contains 99 preserved seed-fern tree trunks. The trees are estimated to have grown about 20 meters in height along what were likely the banks of an ancient river system.
The newly discovered Allan Hills fossil forest, at the base of the 1,800-meter-high Roscolyn Tor, represents the second largest fossil forest in Antarctica, according to Gulbranson. About a dozen fossil forests have been found from an even earlier time period called the Permian, which extends roughly between 298 and 252 million years ago.
“It’s an important find,” said Gulbranson, whose expertise as a sedimentologist and geochemist allows him to reconstruct the environment that existed when these trees, shrubs and forests flourished. He does this by using various techniques, including grinding down small samples of the fossil growth rings to see variations in how the ancient flora once grew.
Video
Paleobotanists discover new plant fossils in Antarctica.
Credit: Peter Rejcek and Ralph Maestas/NSF
