Here the Loki Archaeota were discovered: on the seabed at the Mid-Atlantic Ridge near the hydrothermal vents Loki’s Castle. Credit: Centre for Geobiology, Bergen, Norway, by R.B. Pedersen
New complex microorganisms discovered as closest relatives of complex organisms
Archaea belong together with Bacteria to the first organisms that emerged on Earth. These microorganisms existed hundreds of millions of years before the more complex cell structures of Eukaryotes developed that gave rise to macroscopic life, i.e. plants and animals. An international team of researchers from Uppsala (Sweden), Bergen (Norway) and Vienna (Austria), has found a novel group of Archaea in deep ocean sediments, who are the closest direct relatives of the eukaryotic lineage. Their genome shows an unexpected similarity to those of Eukaryotes. The results of this study appear in the current issue of the journal “Nature”.
How did the first complex eukaryotic cells with their organelles develop from simple prokaryotes, i.e. bacteria or archaea? This is a highly debated topic in evolutionary research but the question remains largely unresolved. Genomic research has shown that the organelles delivering energy in eukaryotic cells stem from an early bacterial symbiont. Since Archaea have also played an important role in the evolution of eukaryotes, current models suggested, that a primordial Archaeon might have engulfed a bacterium and in this event transformed into a complex eukaryotic cell. “With the discovery of Lokiarchaeota a missing link in this scenario has been found”, says Christa Schleper from the University of Vienna.
In phylogenetic trees Lokiarchaeota (named after the Norwegian god Loki) form a direct sister group to Eukaryotes. This means that the ancestors of Eukaryotes emerged indeed directly from Archaea and do not form a separate domain in the tree of life. In addition, the genome of Lokiarchaeota reveals an unexpected complexity: It contains the genetic information for some proteins that were earlier only known from eukaryotes. Some of these proteins are responsible for membrane remodeling and for the formation of a cytoskeleton that determines the shape of a eukaryotic cell. “Exactly those features were needed by the primordial cell or primordial Archaeon to engulf a bacterium in the early stages of eukaryotic evolution”, says Anja Spang, one of the first authors of this study, who recently completed her PhD at the University of Vienna and now analysed the Loki genome in the group of Thijs Ettema in Uppsala.
The last common ancestor
“It is as if we had just discovered the primates i.e. the next living relatives of humans, who also give us interesting insights into the nature of the last common ancestor. However, the common ancestor of Lokiarchaeota and Eukaryotes dates much further back, approximately two billion years”, says Christa Schleper, “We are curious to analyse the life style and cellular structure of Lokiarchaeota, as it might give even more exciting insights into early evolution.”
Reference:
Anja Spang, Jimmy H. Saw, Steffen L. Jørgensen, Katarzyna Zaremba-Niedzwiedzka, Joran Martijn, Anders E. Lind, Roel van Eijk ,Christa Schleper, Lionel Guy and Thijs J.G. Ettema: Complex archaea that bridge the gap between prokaryotes and eukaryotes. In: Nature 2015 DOI: 10.1038/nature14447
A diagram illustrating the possible interior of Saturn’s moon Enceladus, including the ocean and plumes in the south polar region, was based on Cassini spacecraft observations, courtesy of NASA/JPL-Caltech. Credit: NASA/JPL-Caltech
New work from a team including Carnegie’s Christopher Glein has revealed the pH of water spewing from a geyser-like plume on Saturn’s moon Enceladus. Their findings are an important step toward determining whether life could exist, or could have previously existed, on the sixth planet’s sixth-largest moon.
Enceladus is geologically active and thought to have a liquid water ocean beneath its icy surface. The hidden ocean is the presumed source of the plume of water vapor and ice that the Cassini spacecraft has observed venting from the moon’s south polar region. Whenever there’s the possibility of liquid water on another planetary body, scientists begin to ask whether or not it could support life.
The present team, including lead author Glein, John Baross of the University of Washington, and J. Hunter Waite Jr. of the Southwest Research Institute, developed a new chemical model based on mass spectrometry data of ice grains and gases in Enceladus’ plume gathered by Cassini, in order to determine the pH of Enceladus’ ocean. The pH tells us how acidic or basic the water is. It is a fundamental parameter to understanding geochemical processes occurring inside the moon that are considered important in determining Enceladus’ potential for acquiring and hosting life. Their work is published in the journal Geochimica et Cosmochimica Acta.
The team’s model, constrained by observational data from two Cassini teams, including one led by coauthor Waite, shows that the plume, and by inference the ocean, is salty with an alkaline pH of about 11 or 12, which is similar to that of glass-cleaning solutions of ammonia. It contains the same sodium chloride (NaCl) salt as our oceans here on Earth. Its additional substantial sodium carbonate (Na2CO3) makes the ocean more similar to our planet’s soda lakes such as Mono Lake in California or Lake Magadi in Kenya. The scientists refer to it as a “soda ocean.”
“Knowledge of the pH improves our understanding of geochemical processes in Enceladus’ ‘soda ocean,'” Glein explained.
The model suggests that the ocean’s high pH is caused by a metamorphic, underwater geochemical process called serpentinization. On Earth, serpentinization occurs when certain kinds of so-called “ultrabasic” or “ultramafic” rocks (low in silica and high in magnesium and iron) are brought up to the ocean floor from the upper mantle and chemically interact with the surrounding water molecules. Through this process, the ultrabasic rocks are converted into new minerals, including the mineral serpentine, after which the process is named, and the fluid becomes alkaline. On Enceladus, serpentinization would occur when ocean water circulates through a rocky core at the bottom of its ocean.
“Why is serpentinization of such great interest? Because the reaction between the metallic rocks and the ocean water also produces molecular hydrogen (H2), which provides a source of chemical energy that is essential for supporting a deep biosphere in the absence of sunlight inside moons and planets,” Glein said. “This process is central to the emerging science of astrobiology, because molecular hydrogen can both drive the formation of organic compounds like amino acids that may lead to the origin of life, and serve as food for microbial life such as methane-producing organisms. As such, serpentinization provides a link between geological processes and biological processes. The discovery of serpentinization makes Enceladus an even more promising candidate for a separate genesis of life.”
Even beyond the search for life-hosting conditions on other planetary bodies, the team’s work demonstrates that it is possible to determine the pH of an extraterrestrial ocean based on chemical data from a spacecraft flying through a plume. This may be a useful approach to searching for habitable conditions in other icy worlds, such as Jupiter’s moon Europa.
“Our results show that this kind of synergy between observations and modeling can tell us a great deal about the geochemical processes occurring on a faraway celestial object, thus opening the door to an exciting new era of chemical oceanography in the solar system and beyond.” Glein added.
Cinder cone near Mount Lassen Photo Credit: Marli Miller
University of Oregon geologists have tapped water in surface rocks to show how magma forms deep underground and produces explosive volcanoes in the Cascade Range.
“Water is a key player,” says Paul J. Wallace, a professor in the UO’s Department of Geological Sciences and coauthor of a paper in the May issue of Nature Geoscience. “It’s important not just for understanding how you make magma and volcanoes, but also because the big volcanoes that we have in the Cascades — like Mount Lassen and Mount St. Helens — tend to erupt explosively, in part because they have lots of water.”
A five-member team, led by UO doctoral student Kristina J. Walowski, methodically examined water and other elements contained in olivine-rich basalt samples that were gathered from cinder cone volcanoes that surround Lassen Peak in Northern California, at the southern edge of the Cascade chain.
The discovery helps solve a puzzle about plate tectonics and Earth’s deep water cycle beneath the Pacific Ring of Fire, which scientists began studying in the 1960s to understand the region’s propensity for big earthquakes and explosive volcanoes. The ring stretches from New Zealand, along the eastern edge of Asia, north across the Aleutian Islands of Alaska and south along the coast of North and South America. It contains more than 75 percent of the planet’s volcanoes.
To understand how water affects subduction of the oceanic plate, in which layers of different rock types sink into the mantle, the UO team studied hydrogen isotopes in water contained in tiny blobs of glass trapped in olivine crystals in basalt.
To do so, the team used equipment in Wallace’s lab, CAMCOR, the Carnegie Institution in Washington, D.C., and a lab at Oregon State University. CAMCOR is UO’s Advanced Materials Characterization in Oregon, a high-tech extension service located in the underground Lorry I. Lokey Laboratories.
Next, the team fed data gained from the rocks into a complex computer model developed by co-author Ikudo Wada, then of Japan’s Tohoku University. She has since joined the University of Minnesota.
That combination opened a window on how rising temperatures during subduction drive water out of different parts of the subducted oceanic crust, Walowski said. Water migrates upwards and causes the top of the subducted oceanic crust to melt, producing magma beneath the Cascade volcanoes.
The key part of the study, Wallace said, involved hydrogen isotopes. “Most of the hydrogen in water contains a single proton,” he said. “But there’s also a heavy isotope, deuterium, which has a neutron in addition to the proton. It is important to measure the ratio of the two isotopes. We use this ratio as a thermometer, or probe, to study what’s happening deep inside the earth.”
“Melting of the subducting oceanic crust and the mantle rock above it would not be possible without the addition of water,” Walowski said. “Once the melts reach the surface, the water can directly affect the explosiveness of magma. However, evidence for this information is lost to the atmosphere during violent eruptions.”
Reference:
K. J. Walowski, P. J. Wallace, E. H. Hauri, I. Wada, M. A. Clynne. Slab melting beneath the Cascade Arc driven by dehydration of altered oceanic peridotite. Nature Geoscience, 2015; 8 (5): 404 DOI: 10.1038/ngeo2417
Casualty figures were highest for any recorded earthquake in the history of Nepal. In total 8519 people lost their lives in Nepal, A total of 126355 houses were severely damaged and around 80893 buildings were completely destroyed. Total money spent from the earthquake relief fund was NRs 206500 inside Kathmandu valley only. Earthquake relief fund was established by the king, loans were provided for earthquake effected people and earthquake volunteers groups were formed.
An emeritus Oregon State University geologist, who was one of the first scientists to point to the possibility of a major earthquake in the Pacific Northwest, outlines some of the world’s seismic “time bombs” in a forthcoming book.
One of those time bombs listed, in a segment he wrote last year, was Nepal where on April 25, an earthquake estimated at magnitude 7.8 struck the region, killing more than 7,500 people and injuring another 14,500.
Robert Yeats’ prescience is eerily familiar.
Five years ago, Yeats was interviewed by Scientific American on earthquake hazards and outlined the dual threats to Port au Prince, Haiti, of poverty and proximity to a major fault line. One week later, that time bomb went off and more than 100,000 people died in a catastrophic earthquake.
When the Scientific American reporter called Yeats after that seismic disaster to ask if he had predicted the quake, he said no.
“I could say where the time bombs are located – large, rapidly growing cities next to a tectonic plate boundary with a past history of earthquakes, but I had no way of knowing that the bomb would go off a week after my interview,” he said.
Fast forward to 2015 – Yeats has completed a new book, “Earthquake Time Bombs,” which will be published later this year by Cambridge University Press. In that book, he identifies other time bombs around the world; one is a region he has visited frequently in the past 30 years – the Himalayas, including Kathmandu, Nepal, a city of more than a million people.
Yeats points to several areas around the worlds where large cities lie on or adjacent to a major plate boundary creating a ticking time bomb: Tehran, the capital of Iran; Kabul in Afghanistan; Jerusalem in the Middle East; Caracas in Venezuela; Guantanamo, Cuba; Los Angeles, California; and the Cascadia Subduction Zone off the northwestern United States and near British Columbia.
“These places should take lessons from the regions that already have experienced major earthquakes, including Nepal,” said Yeats, who is with OSU’s College of Earth, Ocean, and Atmospheric Sciences.
Like Port au Prince, Kathmandu lies on a tectonic plate boundary – the thrust fault between the high Himalayas and the continent of India to the south. The plate began its northward movement 50 million years ago, Yeats said, and is progressing at the rate of about two-thirds of an inch a year. As the plate is forcing its way beneath Tibet, it is triggering periodic earthquakes along the way.
“It takes time to build up a sufficient amount of stress in these systems, but eventually they will rupture,” Yeats said. “The 2015 Nepal quake was, unquestionably, a disaster with losses of life in the thousands. But it could have been worse.”
“With the assistance of an American non-profit seismology group, the city of Kathmandu created a disaster management unit and a National Society for Earthquake Technology that established committees of citizens to raise awareness and upgrade buildings, especially public schools,” Yeats pointed out. “Other ‘time bombs’ would be wise to do the same.”
Making buildings more earthquake-resistant is imperative for cities near a fault, yet economics often preclude such measures. Yeats said some of the greatest losses in the Nepal quake took place in United Nations World Heritage sites of Bhaktapur and Patan, where ancient buildings had not been strengthened.
“We are not able to predict an earthquake, but we can identify potential trouble,” Yeats said. A seismic gap in the Himalayas was identified years ago by the late Indian seismologist K.N. Khattri in between western Himalaya of India and Kathmandu, where a magnitude 8.1 quake hit in 1934, he pointed out. The earthquake on April 25 struck within Khattri’s seismic gap, Yeats noted.
The 1934 earthquake killed an estimated 20 percent of the population of Kathmandu Valle, some 30,000 people. The population there was much smaller than it is today.
“The 1934 epicenter apparently was east of the city, whereas the epicenter of April 25’s earthquake was to the west, meaning that the two earthquakes may have ruptured different parts of the plate-boundary fault,” Yeats said.
Earlier earthquakes that damaged Kathmandu struck in 1833 and 1255. The location and magnitude of those two quakes are uncertain.
“Videos of this year’s earthquake focused on damaged and destroyed buildings and many of these were old historical buildings that had not been upgraded,” Yeats said. “Photos also showed new buildings that did not appear to be damaged. There’s a lesson there.”
Earthquakes off the east coast of Japan on 11 March 2011: Dotted circles indicate foreshocks, solid circles aftershocks. The size of the largest circle corresponds to the location of the epicenter of the main quake. Credit: NASA Earth Observatory
On 11 March 2011, a massive release of stress between two overlapping tectonic plates occurred beneath the ocean floor off the coast of Japan, triggering a giant tsunami. The Tohoku quake resulted in the death of more than 15,000 people, the partial or total destruction of nearly 400,000 buildings, and major damage to the Fukushima nuclear power plant. This “superquake” may have been the largest in a series of earthquakes, thus marking the end of what’s known as a supercycle: a sequence of several large earthquakes.
A research team at ETH Zurich headed by Taras Gerya, professor of geophysics, and Ylona van Dinther is studying supercycles such as this that occur in subduction zones. Geologists use the term “subduction zone” to refer to the boundary between two tectonic plates along a megathrust fault, where one plate underthrusts the other and moves into the earth’s mantle. These zones are found all over the world: off the South American coast, in the US’s Pacific Northwest, off Sumatra — and of course in Japan.
However, earthquakes don’t occur at just any point along a megathrust fault, but only in the fault’s seismogenic zones. Why? In these zones, friction prevents relative movement of the plates over long periods of time. “This causes stresses to build up; an earthquake releases them all of a sudden,” explains ETH doctoral student Robert Herrendörfer. After the quake has released these stresses, the continued movement of the plates builds up new stresses, which are then released by new earthquakes — and an earthquake cycle is born. In a supercycle, the initial quakes rupture only parts of a subduction zone segment, whereas the final “superquake” affects the entire segment.
Several different theories have been advanced to explain this “gradual rupture” phenomenon, but they all assume that individual segments along the megathrust fault are governed by different frictional properties. “This heterogeneity results in a kind of ‘patchwork rug’,” says Herrendörfer. “To begin with, earthquakes rupture individual smaller patches, but later a ‘superquake’ ruptures several patches all at once.”
More supercycles in broad seismogenic zone
In a new article recently published in Nature Geoscience, Herrendörfer’s research group at ETH proposed a further explanation that doesn’t include this patchwork idea. Simply put: the wider a seismogenic zone, the greater the probability of a supercycle occurring.
To understand this, you first have to picture the physical forces at work in a subduction zone. As one plate dives beneath the other at a particular angle, the plates along the megathrust fault become partially coupled together, so the lower plate pulls the upper one down with it.
The ETH researchers ran computer simulations of this process, with the overriding plate represented by a wedge and the lower by a rigid slab. Since the plates are connected to each other only within the seismogenic zone, the wedge is deformed and physical stresses build up. In the adjacent earthquake-free zones, the plates can move relative to each other.
These stresses build up most rapidly at the edges of the seismogenic zone. If the stress there becomes greater than the plate’s frictional resistance, the wedge decouples from the lower plate and begins to move relative to the subducting plate. As the relative speed increases, the frictional resistance decreases — allowing the wedge to move even faster. The result is a rapid succession of interactions: an earthquake.
The earthquake spreads out, stopping only when it reaches a point where the frictional resistance is once again greater than the stress. That is where the slip event ends and both plates couple together again.
As part of his dissertation work, Herrendörfer has investigated how the width of the seismogenic zone affects this process. The models show that at the start of a supercycle, the difference between the stress and the frictional resistance is very large — and the wider the seismogenic zone, the larger the difference. “This means that the first earthquakes in this area will only partially rupture the seismogenic zone,” says Herrendörfer. In narrower zones, it takes just one earthquake to rupture the entire zone. In wider zones that are about 120 km or more across, the stress is released in a series of several quakes and ultimately in a superquake.
Models not suitable for predicting earthquakes
Empirical data supports this explanation. “To date, supercycles have been observed only in subduction zones with a larger-than-average seismogenic zone about 110 km across,” says Herrendörfer.
Based on their findings, the ETH researchers have defined further regions in addition to those already known as places that could be affected by supercycles — namely, the subduction zones off Kamchatka, the Antilles, Alaska and Java.
However, Herrendörfer cautions against jumping to conclusions. “Our theoretical models represent nature only to a limited extent, and aren’t suitable for predicting earthquakes,” he emphasises. “Our efforts were aimed at improving our understanding of the physical processes at work in an earthquake cycle. In future, this knowledge could be used for generating long-term estimates of the risk of earthquakes.” The method can also be applied to continental collision zones, such as the Himalayan mountain range, where Nepal was recently struck by a devastating quake.
How tectonic plates collide
Subduction zones are convergent boundaries of tectonic plates, areas where plates move towards and against each other. These convergent boundaries also include continental collision zones such as the Alps and the Himalayas, where the Indian plate is colliding with the Asian plate. Other plate boundaries are divergent, where the plates are moving away from each other, such as in Iceland. On transform plate boundaries, plates slide past each other horizontally on a vertical fault. Examples include the San Andreas Fault in California and Turkey’s North Anatolian Fault.
Reference:
Robert Herrendörfer, Ylona van Dinther, Taras Gerya, Luis Angel Dalguer. Earthquake supercycle in subduction zones controlled by the width of the seismogenic zone. Nature Geoscience, 2015; DOI: 10.1038/ngeo2427
Note: The above story is based on materials provided by ETH Zurich. The original article was written by Astrid Tomczak-Plewka.
The village of Chautara, Nepal as seen from space. Credit: Google Earth
Four men trapped under as much as 10 feet of bricks, mud and other debris have been rescued in Nepal thanks to a new search-and-rescue technology developed in partnership by the Department of Homeland Security’s (DHS) Science and Technology Directorate (S&T) and the National Aeronautics and Space Administration’s (NASA) Jet Propulsion Laboratory (JPL). The device called FINDER (Finding Individuals for Disaster and Emergency Response) uses microwave-radar technology to detect heartbeats of victims trapped in wreckage. Following the April 25 earthquake in Nepal, two prototype FINDER devices were deployed to support search and rescue teams in the stricken areas.
“The true test of any technology is how well it works in a real-life operational setting,” said DHS Under Secretary for Science and Technology Dr. Reginald Brothers. “Of course, no one wants disasters to occur, but tools like this are designed to help when our worst nightmares do happen. I am proud that we were able to provide the tools to help rescue these four men.”
The men had been trapped beneath the rubble for days in the hard-hit village of Chautara. David Lewis, president of one of S&T’s commercial partners, R4 Inc. out of Eatontown, N.J., arrived in Nepal with two prototype FINDER devices on April 29 to assist in the rescue efforts. He joined a contingent of international rescuers from China, the Netherlands, Belgium and members of the Nepali Army in Northern Nepal. Using FINDER, they were able to detect two heartbeats beneath each of two different collapsed structures, allowing the rescue workers to find and save the men.
“NASA technology plays many roles: driving exploration, protecting the lives of our astronauts and improving—even saving—the lives of people on Earth,” said Dr. David Miller, NASA’s chief technologist at NASA Headquarters in Washington. “FINDER exemplifies how technology designed for space exploration has profound impacts to life on Earth.”
The FINDER device will be demonstrated on Thursday, May 7, at the Virginia Task Force One Training Facility in Lorton, Va. At this event, which was scheduled long before the Nepali earthquake, S&T and JPL will demonstrate the technology with the assistance of members of Virginia Task Force One. They will also announce its official transition to commercial enterprise where the devices can be manufactured and made available to search and rescue teams around the world.
FINDER has previously demonstrated capabilities of detect people buried under up to 30 feet of rubble, hidden behind 20 feet of solid concrete, and from a distant of 100 feet in open spaces. A new “locator” feature has since been added to not only provide search and rescue responders with confirmation of a heartbeat, but also the approximate location of trapped individuals within about five feet, depending on the type of rubble.
This is a satellite image of Italy, courtesy NASA. Credit: NASA
Geological knowledge is essential for the sustainable development of a “smart city” — one that harmonizes with the geology of its territory. Making a city “smarter” means improving the management of its infrastructure and resources to meet the present and future needs of its citizens and businesses. In the May issue of GSA Today, geologist Donatella de Rita and classical archaeologist Chrystina Häuber explain this idea further by using early Rome and Naples as comparative examples.
The authors describe Rome prior to Republican Times as a smart city because its expansion did not substantially alter the natural features of the area, and natural resources were managed to minimize environmental risks. Rome, which had at that time an economy based on agriculture, developed on small hilltops, and its position on the Tiber alluvial plain ensured fertile soils and easy commerce between river banks. Farms were plentiful, even inside the city walls, ensuring the self-sustenance of the city. Rome was also favored by an abundance of water resources, such as the Tiber and Aniene Rivers, and several natural springs inside the city walls.
In contrast, during the same period, Naples was exposed to more geological hazards and had fewer natural resources. Naples was located within an easily defendable bay, and as such its economy was dominated by sea trade. The rugged geomorphology of Naples’ interior territory significantly limited agriculture and diversification. Rather than being able to expand outward, Naples mostly grew vertically, using as foundations the natural marine terraces bordering the coast. Geomorphology, therefore, played a key role in constraining the importance of Naples to the Roman Empire, according to de Rita and Häuber.
Over time, however, rapid urban expansion and concomitant population growth led to the overuse of resources and increased hazards for both cities, write de Rita and Häuber. As a result, the cities became unstable and fragile, with disasters resulting from several natural processes, such as flooding, volcanism, CO2 emissions, and earthquakes.
Reference:
Donatella de Rita, Chrystina Häuber. The smart city develops on geology: Comparing Rome and Naples. GSA Today, 2015; 4 DOI: 10.1130/GSATG222A.1
The modeled slip on the fault is shown as viewed from above and indicated by the colors and contours within the rectangle. The peak slip in the fault exceeds 19.7 feet (6 meters). The ground motion measured with GPS is shown by the red and purple arrows and was used to develop the fault slip model. Aftershocks are indicated by red dots. Background color and shaded relief reflect regional variations in topography. The barbed lines show where the main fault reaches Earth’s surface. Credit: NASA/JPL-Caltech
Using a combination of satellite radar imaging data, GPS data measured in and near Nepal, and seismic observations from instruments around the world, Caltech and JPL scientists have constructed a preliminary picture of what happened below Earth’s surface during the recent 7.8-magnitude Gorkha earthquake in Nepal.
The team’s observations and models of the April 25, 2015 earthquake, produced through the Advanced Rapid Imaging and Analysis (ARIA) project—a collaboration between Caltech and JPL—include preliminary estimates of the slippage of the fault beneath Earth’s surface that resulted in the deaths of thousands of people. In addition, the ARIA scientists have provided first responders and key officials in Nepal with information and maps that show block-by-block building devastation as well as measurements of ground movement at individual locations around the country.
“As the number of orbiting imaging radar and optical satellites that form the international constellation increases, the expected amount of time it takes to acquire an image of an impacted area will decrease, allowing for products such as those we have made for Nepal to become more commonly and rapidly available,” says Mark Simons, professor of geophysics at Caltech and a member of the ARIA team. “I fully expect that within five years, this kind of information will be available within hours of a big disaster, ultimately resulting in an ability to save more lives after a disaster and to make assessment and response more efficient in both developed and developing nations.”
Over the last five years, Simons and his colleagues in Caltech’s Seismological Laboratory and at JPL have been developing the approaches, infrastructure, and technology to rapidly and automatically use satellite-based observations to measure the movement of Earth’s surface associated with earthquakes, volcanoes, landslides and other geophysical processes.
“ARIA is ultimately aimed at providing tools and data—for use by groups ranging from first responders, to government agencies, and individual scientists—that can help improve situational awareness, response, and recovery after many natural disasters,” Simons says. “The same products also provide key observational constraints on our physical understanding of the underlying processes such as the basic physics controlling seismogenic behavior of major faults.”
Left: Illustration of Ottoia, a prehistoric priapulid, burrowing. Right: Ottoia worm. Credit: Left: Smokeybjb via Wikimedia Commons. Right: Martin Smith.
A new study of teeth belonging to a particularly phallic-looking creature has led to the compilation of a prehistoric ‘dentist’s handbook’ which may aid in the identification of previously unrecognised specimens from the Cambrian period, 500 million years ago.
It sounds like something out of a horror movie: a penis-shaped worm which was able to turn its mouth inside out and drag itself around by its tooth-lined throat, which resembled a cheese grater. But a new study of the rather unfortunately-named penis worm has found that their bizarre dental structure may help in the identification of previously unrecognised fossil specimens from the time on Earth when animals were first coming into their own.
Reconstructing the teeth of penis worms, or priapulids, in fine detail has enabled researchers from the University of Cambridge to compile a ‘dentist’s handbook’ which has aided in the identification of fossilised teeth from a number of previously-unrecognised penis worm species from all over the world. The results are published today (6 May) in the journal Palaeontology.
The researchers used electron microscopy to examine the internal structure of the teeth of these creatures, which first emerged during the ‘Cambrian explosion’, a period of rapid evolutionary development about half a billion years ago, when most major animal groups first appear in the fossil record.
The teeth of these Cambrian priapulids had different shapes according to their function: some were shaped like a cone fringed with tiny prickles and hairs, some were shaped like a bear claw, and some like a city skyline.
During the Cambrian, most animals were soft-bodied, like worms and sponges. Therefore, outside of the few very special places where conditions are just right to enable preservation of soft-bodied creatures, it is difficult to know for certain how far certain species were distributed across the Earth at the time.
“As teeth are the most hardy and resilient parts of animals, they are much more common as fossils than whole soft-bodied specimens,” said Dr Martin Smith, a postdoctoral researcher in Cambridge’s Department of Earth Sciences and the paper’s lead author. “But when these teeth – which are only about a millimetre long – are found, they are easily misidentified as algal spores, rather than as parts of animals. Now that we understand the structure of these tiny fossils, we are much better placed to a wide suite of enigmatic fossils.”
Both modern and Cambrian penis worms have spent their lives burrowing into the sediment beneath the ocean since they first appeared 500 million years ago.
During the Cambrian, penis worms were voracious predators, gobbling up anything that crossed their path, including worms, shrimp and other marine creatures. They were able to turn their mouths inside out to reveal a tooth-lined throat that looked like a prehistoric cheese grater.
These teeth were not just used for eating food, however. By turning their mouths inside out, penis worms could also use their teeth sort of like miniature grappling hooks, using them to grip a surface and then pull the rest of their bodies along behind.
“Modern penis worms have been pushed to the margins of life, generally living in extreme underwater environments,” said Smith. “But during the Cambrian, they were fearsome beasts, and extremely successful ones at that.”
For this study, the researchers examined fossils of Ottoia, a type of penis worm, about the length of a finger, which lived during the Cambrian. The fossils originated from the Burgess Shale in Western Canada, the world’s richest source of fossils from the period, full of weird and wacky-looking creatures that have helped scientists understand how animal life on Earth developed.
Using high resolution electron and optical microscopy, they were able to expose the curious structure of Ottoia’s teeth for the first time. By reconstructing the structure of these teeth in detail, the researchers were then able to identify fossilised teeth of a number of previously-unrecognised penis worm species from all over the world.
“Teeth hold all sorts of clues, both in modern animals and in fossils,” said Smith. “It’s entirely possible that unrecognised species await discovery in existing fossil collections, just because we haven’t been looking closely enough at their teeth, or in the right way.”
Reference:
Martin R. Smith, Thomas H. P. Harvey and Nicholas J. Butterfield, The macro- and microfossil record of the Cambrian priapulid Ottoia. Article first published online: 6 MAY 2015. DOI: 10.1111/pala.12168
This image obtained on May 5, 2015 courtesy of the Institute of Vertebrate Paleontology and Paleoanthropology in Bejing, shows a computer generated image of an Ornithuromorph, a wading bird from the Early Cretaceous period in China. Credit: Institute of Vertebrate Paleontology and Paleoanthropology in Bejing
Modern birds may have evolved six million years earlier than thought, said Chinese palaeontologists Wednesday after analyzing the fossil remains of a previously unknown prehistoric relative.
The extinct species, of which two fossils were discovered in China’s northeastern Hebei province about two years ago, was the earliest known member of the Ornithuromorpha branch that also gave us Neornithes, or modern birds.
“The new fossil represents the oldest record (about 130.7 million years ago) of Ornithuromorpha,” study co-author Wang Min of the Chinese Academy of Sciences told AFP by email.
“It pushed back the origination date of Ornithuromorpha by at least five million years” and the divergence of modern birds by about the same margin.
The previous oldest known example of Ornithuromorpha lived about 125 million years ago.
According to an artist’s impression, the new bird, dubbed Archaeornithura meemannae, shared many features with its modern cousins, apart from tiny, sharp claws on its wings.
It stood about 15 centimetres (six inches) tall on two legs that had no feathers—suggesting it may have been a wader from a lake shore environment.
The fossils were not complete enough to determine whether the creature had teeth—a common feature of birds from the Early Cretaceous period, a sub-division of the Mesozoic era.
Like some modern birds, it may have used gastroliths, or stomach stones, to break down hard foods like seeds, and it was likely a plant-eater, said Wang.
In the artist’s recreation, it sports a striking, purple feather crown.
Ornithuromorpha are believed to have comprised about half of bird species that lived during the Mesozoic era, which lasted from about 252 million to 66 million years ago. Some evolved into living birds.
Other Mesozoic groups like Enantiornithes, which had teeth and clawed wings, are not thought to have left any living descendents.
Mesozoic bird fossils are rare, and very little is known about the early evolutionary history of birds.
The earliest known relative of birds is thought to be Archaeopteryx, considered a transitional species from non-avian dinosaurs with feathers which lived about 150 million years ago.
Note : The above story is based on materials provided by AFP.
Fig. 1 Tyrannosaurid tooth from the Nanxiong Formation of Jiangxi Province, in labial (A and B), lingual (C), mesial (D), distal (E), basal (F), and apical (G) views. Arrow indicates distal carina location. Scale bar equals 10 mm in A, and 20 mm in B-G. Credit: MO Jinyou
Large carnivorous dinosaurs, are common in the Late Cretaceous of Asia, but only some fragment teeth have been recovered from southern China. In a paper published in the latest issue of Vertebrata PalAsiatica, Dr. XU Xing, Institute of Vertebrate Paleontology and Paleoanthropology (IVPP) of the Chinese Academy of Sciences, and MO Jinyou, Natural History Museum of Guangxi in Nanning reported two isolated, large predatory theropod teeth from the Upper Cretaceous of southern China. The smaller tooth is assigned to a tyrannosaurid, whereas the larger one is greatly distinct from other known Late Cretaceous theropods, probably represents a previously unrecognized large predatory dinosaur.
These large predatory theropod teeth were discovered for the first time from the Upper Cretaceous Nanxiong Formation of Jiangxi, helping better understand the known diversity of vertebrates from the Upper Cretaceous Nanxiong Formation, southern China.
The crown height of the smaller tooth is 76 mm. It is identified as a typical tooth of a large tyrannosaurid based on large and suboval in cross-section. The crown base ratio, about 0.72, is within the range seen in Tyrannosaurus rex, and the chisel-shaped distal denticles are similar to those of tyrannosaurids.
The larger tooth is moderately laterally compressed, with well defined longitudinal oriented enamel wrinkles at the basal halves of the mesial and distal margins. The crown height of the larger tooth is 91 mm. It probably represents a previously unknown large theropod inhabited Asia during the Late Cretaceous.
The Nanxiong Formation or its equivalents are exposed in several provinces of southeastern China and represented by a thick sequence of red mudstones, sandstones and conglomerates. In Jiangxi, these red beds have yielded dinosaurs and other vertebrate fossils since 1965, including turtles, lizards, dinosaur eggs, small theropods, and sauropods.
This work was supported by the National Natural Science Foundation of China.
Fig. 2 Large theropod tooth from the Nanxiong Formation of Jiangxi Province, in lingual (A, B), labial (C, D), basal (E), mesial (F, G), and distal (H, I) views. Arrow marks the end of mesial carina. The white frames in C, F, and H mark the tooth area displayed in enlarged form in images D, G, and I, respectively. Scale bars equal 10 mm in A, D, G, and I; 20 mm in B, C, E, F, and H. Credit: MO Jinyou
Capelatus prykei is so different from any of the world’s other diving beetles that it has been placed in a new genus all of its own. Credit: David Bilton/Plymouth University
A striking new species of beetle with no direct relatives has been identified by a scientist from Plymouth University living in wetlands on the outskirts of Cape Town.
Capelatus prykei is so different from any of the world’s other diving beetles that it has been placed in a new genus all of its own, with its nearest relations to be found around the Mediterranean and in New Guinea.
In a study, published in the journal Systematic Entomology, scientists used a combination of morphological and molecular data to study Capelatus, and establish it as a highly distinctive, and apparently endangered, member of the world fauna.
Capelatus prykei measures between 8-10mm, large in comparison to most copelatine diving beetles, and was discovered in areas of relatively dense vegetation within the Noordhoek Wetlands.
Dr David Bilton, Reader in Aquatic Biology at Plymouth University, said: “Capelatus prykei immediately looks odd, quite unlike any previously known diving beetle. It’s fairly common to find new species of beetle, but it’s much less usual to find things which are so different they have to be put in their own genus. Our study of DNA sequences shows that the closest relatives of Capelatus live thousands of miles away, and that they last shared a common ancestor around 30-40 million years ago.
“This beetle’s a real evolutionary relic, which only seems to have survived in a very small area close to Cape Town, probably because this region has had a relatively stable climate over the last few million years. Today Capelatus is extremely rare though – in fact we know of only one population, fortunately located inside Table Mountain National Park. We’ve also found old, unnamed specimens in the Natural History Museum in London, but the area where these were caught in the 1950s is now under the suburbs of the city.”
Dr Bilton first began sampling water beetles in the area as a result of annual field trips to South Africa by undergraduates on the BSc (Hons) in Marine Biology and Coastal Ecology, and has found dozens of new species in the area in the last five years. This study, written in conjunction with Plymouth entomologist Clive Turner and colleagues from the Museum of Zoology in Munich, really highlights the unique biological diversity of the region.
The Western Cape of South Africa hosts one of the world’s hottest biodiversity hotspots, and supports around 20 per cent of the plant species found in the whole of sub-Saharan Africa – most of which are restricted to the region.
The region is also home to a significant number of endemic reptiles, amphibians, freshwater fishes and insects and some of these, like Capelatus, lack close living relatives outside the region, making it one of the most biologically unique places on the planet.
The current study suggests that among such isolated species, Capelatus prykei is particularly under threat and that, as such, immediate action should be taken by conservation agencies.
“On the basis of available data, it is suggested that Capelatus prykei be afforded a provisional IUCN conservation status of Critically Endangered,” the authors say. “If the phylogenetic uniqueness of Capelatus prykei is also taken into consideration, it is clear that a better understanding of the range and requirements of this newly discovered taxon represents a priority for conservation, in both a regional and global context.”
Type specimen of Euanthus panii (L) and its reconstruction picture. Image Credit : CAS
The world’s first typical flower may date back to 162 million years ago, more than 37 million years earlier than previously thought, Chinese researchers reported in a new study.
The fossil flower, named Euanthus panii, was found in western Liaoning Province, according to the study, which was published in the recent edition of the UK-based Historical Biology, an international journal of paleobiology.
The findings were made by Wang Xin, a research fellow at the Nanjing Institute of Geology and Paleobiology of the Chinese Academy of Sciences, and Liu Zhongjian, a professor at the National Orchid Conservation Center.
“Euanthus demonstrates a typical flower organization, including sepals, petals, androecium of tetrasporangiate dithecate anthers and gynoecium with enclosed ovules, implying that flowers were already in place in the Jurassic period. Since enclosed ovules, tetrasporangiate dithecate anther and flower-like organisation are all seen in Euanthus, we place Euanthus among angiosperms with decent confidence,” the researchers wrote in the study.
Wang said his colleague Liu had collected tens of thousands of fossils in the 1970s and 1980s, including Euanthus, but relevant research did not begin until 2013, yangtse.com reported on Tuesday.
According to Wang, Euanthus is very small, only about 1 square centimeter, and may have relied on wind for pollination since there were no bees 162 million years ago. (ECNS)
In this artist’s rendering, the left image shows what Earth looked like more than 140 million years ago, when India was part of an immense supercontinent called Gondwana. The right image shows Earth today. Image: iStock (edited by MIT News)
In the history of continental drift, India has been a mysterious record-holder.
More than 140 million years ago, India was part of an immense supercontinent called Gondwana, which covered much of the Southern Hemisphere. Around 120 million years ago, what is now India broke off and started slowly migrating north, at about 5 centimeters per year. Then, about 80 million years ago, the continent suddenly sped up, racing north at about 15 centimeters per year — about twice as fast as the fastest modern tectonic drift. The continent collided with Eurasia about 50 million years ago, giving rise to the Himalayas.
For years, scientists have struggled to explain how India could have drifted northward so quickly. Now geologists at MIT have offered up an answer: India was pulled northward by the combination of two subduction zones — regions in the Earth’s mantle where the edge of one tectonic plate sinks under another plate. As one plate sinks, it pulls along any connected landmasses. The geologists reasoned that two such sinking plates would provide twice the pulling power, doubling India’s drift velocity.
The team found relics of what may have been two subduction zones by sampling and dating rocks from the Himalayan region. They then developed a model for a double subduction system, and determined that India’s ancient drift velocity could have depended on two factors within the system: the width of the subducting plates, and the distance between them. If the plates are relatively narrow and far apart, they would likely cause India to drift at a faster rate.
The group incorporated the measurements they obtained from the Himalayas into their new model, and found that a double subduction system may indeed have driven India to drift at high speed toward Eurasia some 80 million years ago.
“In earth science, it’s hard to be completely sure of anything,” says Leigh Royden, a professor of geology and geophysics in MIT’s Department of Earth, Atmospheric and Planetary Sciences. “But there are so many pieces of evidence that all fit together here that we’re pretty convinced.”
Royden and colleagues including Oliver Jagoutz, an associate professor of earth, atmospheric, and planetary sciences at MIT, and others at the University of Southern California have published their results this week in the journal Nature Geoscience.
Based on the geologic record, India’s migration appears to have started about 120 million years ago, when Gondwana began to break apart. India was sent adrift across what was then the Tethys Ocean — an immense body of water that separated Gondwana from Eurasia. India drifted along at an unremarkable 40 millimeters per year until about 80 million years ago, when it suddenly sped up to 150 millimeters per year. India kept up this velocity for another 30 million years before hitting the brakes — just when the continent collided with Eurasia.
“When you look at simulations of Gondwana breaking up, the plates kind of start to move, and then India comes slowly off of Antarctica, and suddenly it just zooms across — it’s very dramatic,” Royden says.
In 2011, scientists believed they had identified the driving force behind India’s fast drift: a plume of magma that welled up from the Earth’s mantle. According to their hypothesis, the plume created a volcanic jet of material underneath India, which the subcontinent could effectively “surf” at high speed.
However, when others modeled this scenario, they found that any volcanic activity would have lasted, at most, for 5 million years — not nearly enough time to account for India’s 30 million years of high-velocity drift.
Squeezing honey
Instead, Royden and Jagoutz believe that India’s fast drift may be explained by the subduction of two plates: the tectonic plate carrying India and a second plate in the middle of the Tethys Ocean.
In 2013, the team, along with 30 students, trekked through the Himalayas, where they collected rocks and took paleomagnetic measurements to determine where the rocks originally formed. From the data, the researchers determined that about 80 million years ago, an arc of volcanoes formed near the equator, which was then in the middle of the Tethys Ocean.
A volcanic arc is typically a sign of a subduction zone, and the group identified a second volcanic arc south of the first, near where India first began to break away from Gondwana. The data suggested that there may have been two subducting plates: a northern oceanic plate, and a southern tectonic plate that carried India.
Back at MIT, Royden and Jagoutz developed a model of double subduction involving a northern and a southern plate. They calculated how the plates would move as each subducted, or sank into the Earth’s mantle. As plates sink, they squeeze material out between their edges. The more material that can be squeezed out, the faster a plate can migrate. The team calculated that plates that are relatively narrow and far apart can squeeze more material out, resulting in faster drift.
“Imagine it’s easier to squeeze honey through a wide tube, versus a very narrow tube,” Royden says. “It’s exactly the same phenomenon.”
Royden and Jagoutz’s measurements from the Himalayas showed that the northern oceanic plate remained extremely wide, spanning nearly one-third of the Earth’s circumference. However, the southern plate carrying India underwent a radical change: About 80 million years ago, a collision with Africa cut that plate down to 3,000 kilometers — right around the time India started to speed up.
The team believes the diminished plate allowed more material to escape between the two plates. Based on the dimensions of the plates, the researchers calculated that India would have sped up from 50 to 150 millimeters per year. While others have calculated similar rates for India’s drift, this is the first evidence that double subduction acted as the continent’s driving force.
“It’s a lucky coincidence of events,” says Jagoutz, who sees the results as a starting point for a new set of questions. “There were a lot of changes going on in that time period, including climate, that may be explained by this phenomenon. So we have a few ideas we want to look at in the future.”
Reference:
Oliver Jagoutz, Leigh Royden, Adam F. Holt, Thorsten W. Becker. Anomalously fast convergence of India and Eurasia caused by double subduction. Nature Geoscience, 2015; DOI: 10.1038/ngeo2418
Molten lava, rocks and gas went flying through the air on Hawaii’s Kilauea volcano after an explosion was caused by the partial collapse of a crater wall.
The collapse triggered a small explosion, spreading lava and debris around the rim of Kilauea’s Halemaumau Crater, the U.S. Geological Survey’s Hawaiian Volcano Observatory says.
Janet Babb, a geologist with the USGS, compared the blast on Sunday to taking a hammer to the top of a bottle of champagne.
“You look at the bottle and you see the liquid, but you don’t see the gas,” she said. “There’s a lot of gas in the lava. And so, when that rock fall hits the lava lake, it’s like the moment you knock the top of the champagne bottle off and that gas is released and it hurls molten lava and rock fragments.”
Rocks overhanging the lava lake are altered by gases coming from the lava, Babb said. The rocks eventually give way and collapse into the lava, causing an explosion.
The material was hurled about 280 feet skyward, she said.
Video of the event shows a wall of rocks sliding into a lava lake that last week rose to a record-high level. The slide caused an explosion that sent fist-size chunks of rock onto the closed Halemaumau visitor overlook, according to the Geological Survey. The area has been closed since 2008, when the lava lake formed, and no one was injured.
There could be fallout of ash and dust from this type of event, but it’s very unlikely that anyone could be injured, Babb said. Wind direction dictates the amount of debris that lands in visitor areas, and it is relatively common, she said.
The last time molten lava was visible in the crater was in 1982, when a fissure erupted. The last time there was a lake similar to this one was in 1974.
The vent within Halemaumau Crater has been rising and falling since it first opened, but it reached a record high last week. Even at its previous highest level in October 2012, the lake was too low for people to see. During the day, people could view the gas rising from the lake, and at night people could see the orange glow from the lava.
From the early 1800s up until 1924, there was a continuous lake of lava at Kilauea summit within Halemaumau. At that time, the crater was about half the diameter of what it is now.
In 1924, there was a huge eruption inside the volcano that doubled the size of the crater.
Since 1924, lava lakes have been present at different times. In 1967 and 1968, the entire crater was filled with molten lava. You can still see a “bathtub ring” on the walls of the crater where the lava had risen to at that time.
A magnitude 3.6 earthquake was felt in the area early Monday morning, according to the Geological Survey.
This photo shows a spectacular sigmoidal jointing within a very thick lava flow from the Ambenali formation in the Western Ghats area of India. See related open-access article by M.A. Richards et al. Credit: M.A. Richards and colleagues, and GSA Bulletin
In a new paper published online by GSA Bulletin on 30 April, researchers Mark Richards and colleagues address the “uncomfortably close” occurrence of the Chicxulub impact in the Yucatán and the most voluminous phase of the Deccan Traps flood basalt eruptions in India. Specifically, the researchers argue that the impact likely triggered most of the immense eruptions of lava in India — that indeed, this was not a coincidence, but a cause-and-effect relationship.
Knowledge and study of the Deccan Traps eruptions have consistently cast a shadow of doubt on the theory that the Chicxulub impact was the sole cause of the end-Cretaceous mass extinction, most infamous for killing off Earth’s dinosaurs. But Richards and colleagues write that historical evidence for the triggering of volcanoes by large earthquakes, coupled with a wide range of data, show that the massive outpouring of Deccan lavas are likely to have been triggered by the Chicxulub impact — and thus following on as a secondary disaster.
“The chances of that occurring at random are minuscule,” says Richards. “It’s not a very credible coincidence.”
Several of the authors 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. This geological evidence likely indicates a period of quiescence in Deccan volcanism prior to the Chicxulub impact, which, says Richards, “gave this thing a shake,” thus mobilizing a huge amount of magma over a short period of time.
Richards and colleagues write that while the Deccan eruptions probably spewed massive 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.”
This article is open access online. Co-authors of the paper are Paul Renne, Michael Manga, Stephen Self, and Courtney Sprain, all from UC-Berkeley; Walter Alvarez, a UC-Berkeley professor emeritus and the co-originator of the dinosaur-killing asteroid theory; Leif Karlstrom of the University of Oregon; Jan Smit of Vrije Universeit in Amsterdam; Loÿc Vanderkluysen of Drexel University in Philadelphia; and Sally A. Gibson of the University of Cambridge, UK. Learn more about this team’s research via the UC-Berkeley newsroom.
Reference:
M. A. Richards, W. Alvarez, S. Self, L. Karlstrom, P. R. Renne, M. Manga, C. J. Sprain, J. Smit, L. Vanderkluysen, S. A. Gibson. Triggering of the largest Deccan eruptions by the Chicxulub impact. Geological Society of America Bulletin, 2015; DOI: 10.1130/B31167.1
Cold seeps, the sites on the ocean floor where the bubbles of the methane gas rise up, are a home for a varied communities of bacteria, bivalves and other associated life forms. Credit: NOAA-OER/BOEM/USGS
Offshore the Svalbard archipelago, methane gas is seeping out of the seabed at the depths of several hundred meters. These cold seeps are a home to communities of microorganisms that survive in a chemosynthetic environment — where the fuel for life is not the sun, but the carbon rich greenhouse gas.
There is a large, and relatively poorly understood, community of methane-consuming bacteria in this environment. They gorge on the gas, control its concentration in the ocean, and stop it from reaching the ocean surface and released into the atmosphere.
In the atmosphere methane is a much more potent climate gas than CO2 and it can amplify current global warming.
However, a new study published in Nature Geoscience shows that ocean currents can have a strong impact on this bacterial methane filter.
Oceanographer Benedicte Férré, who is a team leader at CAGE, is a co-author of the study. It shows that the level of activity of the methane-consuming bacteria varied drastically over very short time spans.
The international team of scientists behind this study was able to detect that the fluctuations in bacterial communities changed at the whim of the West Spitsbergen Current that carries warm water from Norwegian Sea to Arctic Ocean. Important oceanographic factors such as water temperature and salinity changed.
The warm and salty current swept over the methane seeping sites, and carried bacteria communities away, thus disturbing methane filtration processes.
Important for the future release
This bacteria filter could become even more important in the future, because environmental change can cause bottom water warming in the Arctic Ocean.
As a consequence methane rich gas hydrates in the ocean floor dissociate, and release even more gas to the water column. This could increase food supply for bacteria. But whether bacteria are able to consume the methane depends on ocean current dynamics as documented by Ferre and her team.
Future methane release from the ocean to the atmosphere will depend on ocean currents.
“We were able to show that strength and variability of ocean currents control the prevalence of methanotrophic bacteria,” says Lea Steinle from University of Basel and the lead author of the study, “therefore, large bacteria populations cannot develop in a strong current, which consequently leads to less methane consumption.”
Reference:
Lea Steinle, Carolyn A. Graves, Tina Treude, Bénédicte Ferré, Arne Biastoch, Ingeborg Bussmann, Christian Berndt, Sebastian Krastel, Rachael H. James, Erik Behrens, Claus W. Böning, Jens Greinert, Célia-Julia Sapart, Markus Scheinert, Stefan Sommer, Moritz F. Lehmann, Helge Niemann. Water column methanotrophy controlled by a rapid oceanographic switch. Nature Geoscience, 2015; 8 (5): 378 DOI: 10.1038/ngeo2420
Given the importance of water in Australia, surprisingly, there is relatively little information about the past variability of rainfall on this continent. Although there is a good annual record of the past 100 years in Australia, there is nothing much before that period and no known cave deposit records exist for New South Wales.
The Australian Nuclear Science and Technology Organisation (ANSTO), University of New South Wales (UNSW) Australia and the National Parks and Wildlife Service (NPWS) have collaborated on research, which appears in the Journal of Hydrology (Markowska et al. 2015). The group is interested in interpreting the rainfall record of the past 2000 years in Australia, because understanding past climate can help predict the availability of water resources in the future.
The study is taking place in the Snowy Mountains, which are an important study site as the area provides an important source of water for the Murrumbidgee and Murray River systems, two major waterways in southeast Australia. The limestone deposit contains a system of about 400 caves managed by the NPWS. Geologists suggest that the caves were formed about 440 million years ago.
Researchers working in underground caves studying when rainfall reaches the subsurface (groundwater recharge) at Yarrangobilly Caves in the Snowy Mountains have found new information that will help reconstruct past climates and groundwater recharge from cave deposits. Cave deposits, or speleothems, are mineral accumulations formed by calcium-rich water in underground caverns. They are important because they can be used to establish a record of past environmental changes, such as rainfall variability.
Lead author, Institute of Environmental Research scientist Monika Markowska and colleagues have been monitoring dripping water, which forms stalagmites, for fifteen months in the cave system, which is located in Kosciuszko National Park.
“Monitoring the water movement from the surface to the cave is important because it carries the majority of the climate and environmental information from the surface,” according to Prof Andy Baker of UNSW Australia, a co-author on the paper.
In this study researchers found that the soil moisture content may be more important than the amount of rainfall in the formation of stalagmites. “Although rainfall is essential for groundwater recharge, at Harrie Wood Cave it was the antecedent soil moisture saturation (i.e. wet or dry preconditions) that controlled whether water from individual rainfall events reached the underground cave system.” said Markowska.
The research team came to this conclusion after a detailed analysis of drip water flow at 14 sites within the Harrie Wood Cave taken at 15-minute intervals and weather data from the surface above the cave. By monitoring drip rates, researchers can determine how long it took the water to get into the cave. They also monitored precipitation, temperature, barometric pressure and soil moisture.
In the cave, dripping water was automatically recorded using Stalagmate® drip logger, devices similar to a miniature, watertight, plastic drum that records each drip from the vibration measured each time a water droplet hits its surface. The data from 14 sites reported in the paper are part of a network of fifty devices placed in the cave, one of the largest such studies in the world. Interpreting the data provided by the Stalagmate® loggers provided a unique way to classify and understand water flow from the surface to the cave.
The researchers identified five different types of drip water responses to surface climate and were surprised to see different flow patterns in drips in close proximity to each other.
The five types of response are due to the many possible water flow paths from the surface to the cave, with water potentially stored in both the soil and in fractures and solution pockets in the limestone, before reaching the cave.
Most importantly, the research demonstrates that speleothems can have very individual relationships to the surface climate due to the specific water flow route. This information has allowed researchers to identify which speleothems can be used to obtain a rainfall record for the past 2000 years.
Stalagmites, a speleothem, are important because they can be analysed using mass spectroscopy to determine records of past climate. The decay of uranium-234 into thorium from the calcite in a stalagmite can be measured to determine age. The ratio of oxygen-18 and oxygen-16 can provide information about rainfall.
Reference:
“Unsaturated zone hydrology and cave drip discharge water response: Implications for speleothem paleoclimate record variability,” Journal of Hydrology, DOI: 10.1016/j.jhydrol.2014.12.044
While fjords are celebrated for their beauty, these ecosystems are also major carbon sinks that likely play an important role in the regulation of the planet’s climate, new research reveals. Credit: Candida Savage
While fjords are celebrated for their beauty, these ecosystems are also major carbon sinks that likely play an important role in the regulation of the planet’s climate, new research reveals.
The finding is newly published in the international journal Nature Geoscience.
After studying sediment data from worldwide fjord systems, the researchers, who include Dr Candida Savage of New Zealand’s University of Otago, estimate that about 18 million tonnes of organic carbon (OC) is buried in fjords each year, equivalent to 11% of annual marine carbon burial globally.
Dr Savage and colleagues calculated that per unit area, fjord organic carbon burial rates are twice as large as the ocean average.
“Therefore, even though they account for only 0.1% of the surface area of oceans globally, fjords act as hotspots for organic carbon burial,” Dr Savage says.
Fjords are long, deep and narrow estuaries formed at high latitudes during glacial periods as advancing glaciers incise major valleys near the coast. They are found in North Western Europe, Greenland, North America, New Zealand, and Antarctica.
As deep and often low oxygen marine environments, fjords provide stable sites for carbon-rich sediments to accumulate, Dr Savage says.
Carbon burial is an important natural process that provides the largest carbon sink on the planet and influences atmospheric carbon dioxide (CO2) levels at multi-thousand-year time scales.
In the Nature Geoscience article, the researchers suggest that fjords may play an especially important role as a driver of atmospheric CO2 levels during times when ice sheets are advancing or retreating.
Earth is currently in an interglacial period after ice sheets receded around 11,700 years ago.
During glacial retreats, fjords would trap and prevent large volumes of organic carbon flowing out to the continental shelf, where chemical processes would have caused CO2 to be produced, says Dr Savage.
Once glaciers started advancing again this material would likely then be pushed out onto the shelf and CO2 production would increase.
“In essence, fjords appear to act as a major temporary storage site for organic carbon in between glacial periods. This finding has important implications for improving our understanding of global carbon cycling and climate change,” she says.
The research involved fieldwork in Fiordland and analysing data from 573 surface sediment samples and 124 sediment cores from fjords around the world.
Reference:
Richard W. Smith, Thomas S. Bianchi, Mead Allison, Candida Savage, Valier Galy. High rates of organic carbon burial in fjord sediments globally. Nature Geoscience, 2015; DOI: 10.1038/ngeo2421
NASA data and expertise are providing valuable information for the ongoing response to the April 25, 2015, magnitude 7.8 Gorkha earthquake in Nepal. The quake has caused significant regional damage and a humanitarian crisis. Credit: NASA/JPL/Ionosphere Natural Hazards Team
NASA and its partners are gathering the best available science and information on the April 25, 2015, magnitude 7.8 earthquake in Nepal, referred to as the Gorkha earthquake, to assist in relief and humanitarian operations. Organizations using these NASA data products and analyses include the U.S. Geological Survey, United States Agency for International Development (USAID)/Office of U.S. Foreign Disaster Assistance, World Bank, American Red Cross, and the United Nations Children’s Fund.
NASA and its collaborators are pulling optical and radar satellite data from international and domestic partners and compiling them into a variety of products. The products include “vulnerability maps,” used to determine risks that may be present; and “damage proxy maps,” used to determine the type and extent of existing damage. Such products can be used to better direct response efforts.
The satellite data will be used to compile maps of ground surface deformation and to create risk models. NASA and its partners are also contributing to assessments of damage to infrastructure. They are tracking remote areas that may be a challenge for relief workers to reach, as well as areas that could be at risk for landslides, river damming, floods and avalanches. The data will contribute to ongoing investigations of our restless Earth and its impacts on society.
NASA is helping get satellite data into the hands of government officials in Nepal where Internet bandwidth is limited. The joint NASA-USAID SERVIR project is supporting disaster response mapping efforts through the SERVIR-Himalaya office at the International Centre for Integrated Mountain Development in Kathmandu. SERVIR staff at NASA’s Marshall Space Flight Center, Huntsville, Alabama, are coordinating image tasking, processing, compression, and distribution efforts with colleagues from Goddard Space Flight Center in Greenbelt, Maryland, and the Jet Propulsion Laboratory in Pasadena, California.
NASA technology that can locate people trapped beneath collapsed buildings is being deployed to Nepal. A remote-sensing radar technology called FINDER (Finding Individuals for Disaster and Emergency Response), developed by JPL in conjunction with the U.S. Department of Homeland Security’s Science and Technology Directorate, can locate individuals buried as deep as 30 feet (9.1 meters) in crushed materials, hidden behind 20 feet (6 meters) of solid concrete, and from a distance of 100 feet (30.5 meters) in open spaces. This technology, licensed by the private entity R4 Incorporated of Edgewood, Maryland, has been taken to Nepal to assist with recovery efforts.
NASA uses the vantage point of space to increase our understanding of our home planet, improve lives and safeguard our future. NASA develops new ways to observe and study Earth’s interconnected natural systems with long-term data records. The agency freely shares this unique knowledge and works with institutions around the world to gain new in-sights into how our planet is changing.
Note : The above story is based on materials provided by NASA.
