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Water-Rock Reaction May Provide Enough Hydrogen 'Food' to Sustain Life in Ocean's Crust or On Mars

A chemical reaction between iron-containing minerals and water may produce enough hydrogen "food" to sustain microbial communities living in pores and cracks within the enormous volume of rock below the ocean floor and parts of the continents, according to a new study led by the University of Colorado Boulder.

The findings, published in the journal Nature Geoscience, also hint at the possibility that hydrogen-dependent life could have existed where iron-rich igneous rocks on Mars were once in contact with water.

Scientists have thoroughly investigated how rock-water reactions can produce hydrogen in places where the temperatures are far too hot for living things to survive, such as in the rocks that underlie hydrothermal vent systems on the floor of the Atlantic Ocean. The hydrogen gases produced in those rocks do eventually feed microbial life, but the communities are located only in small, cooler oases where the vent fluids mix with seawater.

The new study, led by CU-Boulder Research Associate Lisa Mayhew, set out to investigate whether hydrogen-producing reactions also could take place in the much more abundant rocks that are infiltrated with water at temperatures cool enough for life to survive.

"Water-rock reactions that produce hydrogen gas are thought to have been one of the earliest sources of energy for life on Earth," said Mayhew, who worked on the study as a doctoral student in CU-Boulder Associate Professor Alexis Templeton's lab in the Department of Geological Sciences.

"However, we know very little about the possibility that hydrogen will be produced from these reactions when the temperatures are low enough that life can survive. If these reactions could make enough hydrogen at these low temperatures, then microorganisms might be able to live in the rocks where this reaction occurs, which could potentially be a huge subsurface microbial habitat for hydrogen-utilizing life."

When igneous rocks, which form when magma slowly cools deep within Earth, are infiltrated by ocean water, some of the minerals release unstable atoms of iron into the water. At high temperatures -- warmer than 392 degrees Fahrenheit (200 degrees Celsius) -- scientists know that the unstable atoms, known as reduced iron, can rapidly split water molecules and produce hydrogen gas, as well as new minerals containing iron in the more stable, oxidized form.

Mayhew and her co-authors, including Templeton, submerged rocks in water in the absence of oxygen to determine if a similar reaction would take place at much lower temperatures, between 122 and 212 degrees Fahrenheit (50 to 100 degrees Celsius). The researchers found that the rocks did create hydrogen -- potentially enough hydrogen to support life.

To understand in more detail the chemical reactions that produced the hydrogen in the lab experiments, the researchers used "synchrotron radiation" -- which is created by electrons orbiting in a humanmade storage ring -- to determine the type and location of iron in the rocks on a microscale.

The researchers expected to find that the reduced iron in minerals like olivine had converted to the more stable oxidized state, just as occurs at higher temperatures. But when they conducted their analyses at the Stanford Synchrotron Radiation Lightsource at Stanford University, they were surprised to find newly formed oxidized iron on "spinel" minerals found in the rocks. Spinels are minerals with a cubic structure that are highly conductive.

Finding oxidized iron on the spinels led the team to hypothesize that, at low temperatures, the conductive spinels were helping facilitate the exchange of electrons between reduced iron and water, a process that is necessary for the iron to split the water molecules and create the hydrogen gas.

"After observing the formation of oxidized iron on spinels, we realized there was a strong correlation between the amount of hydrogen produced and the volume percent of spinel phases in the reaction materials," Mayhew said. "Generally, the more spinels, the more hydrogen."

Not only is there a potentially large volume of rock on Earth that may undergo these low temperature reactions, but the same types of rocks also are prevalent on Mars, Mayhew said. Minerals that form as a result of the water-rock reactions on Earth have been detected on Mars as well, which means that the process described in the new study may have implications for potential Martian microbial habitats.

Mayhew and Templeton are already building on this study with their co-authors, including Thomas McCollom at CU-Boulder's Laboratory for Atmospheric and Space Physics, to see if the hydrogen-producing reactions can actually sustain microbes in the lab.

Source: Science Daily

R.Sawas

Small, Speedy Plant-Eater Extends Knowledge of Dinosaur Ecosystems

Dinosaurs are often thought of as large, fierce animals, but new research highlights a previously overlooked diversity of small dinosaurs. A team of paleontologists from the University of Toronto, Royal Ontario Museum, Cleveland Museum of Natural History and University of Calgary have described a new dinosaur, the smallest plant-eating dinosaur species known from Canada. Albertadromeus syntarsus was identified from a partial hind leg, and other skeletal elements, that indicate it was a speedy runner. Approximately 1.6 m (5 ft) long, it weighed about 16 kg (30 lbs), comparable to a large turkey.

Albertadromeus lived in what is now southern Alberta in the Late Cretaceous, about 77 million years ago. Albertadromeus syntarsus means "Alberta runner with fused foot bones." Unlike its much larger ornithopod cousins, the duckbilled dinosaurs, its two fused lower leg bones would have made it a fast, agile two-legged runner. This animal is the smallest known plant-eating dinosaur in its ecosystem, and researchers hypothesize that it used its speed to avoid predation by the many species of meat-eating dinosaurs that lived at the same time.

Why are so few small-bodied dinosaurs known from North America some 77 million years ago? Smaller animals are less likely to be preserved than larger ones, because their bones are more delicate and are often destroyed before being fossilized. "We know from our previous research that there are preservational biases against the bones of these small dinosaurs," said Caleb Brown of the University of Toronto, lead author of the study. "We are now starting to uncover this hidden diversity, and although skeletons of these small ornithopods are both rare and fragmentary, our study shows that these dinosaurs were more abundant in their ecosystems than previously thought".

The reason for our relatively poor understanding of these small dinosaurs is a combination of the taphonomic processes described above, and biases in the way that material has been collected. Small skeletons are more prone to destruction by carnivores, scavengers and weathering processes, so fewer small animals are available to become fossils and smaller animals are often more difficult to find and identify than those of larger animals.

"Albertadromeus may have been close to the bottom of the dinosaur food chain but without dinosaurs like it you'd not have giants like T. rex," said Michael Ryan. "Our understanding of the structure of dinosaur ecosystems is dependent on the fossils that have been preserved. Fragmentary, but important, specimens like that of Albertadromeus suggest that we are only beginning to understand the shape of dinosaur diversity and the structure of their communities".

Source: Science Daily

N.H.Khider

Frog-Like Robot Will Help Surgeons

The tiny device is one of a growing stable of bio-inspired robots being built in the University's School of Mechanical Engineering.

It is designed to move across the internal abdominal wall of a patient, allowing surgeons to see what they are doing on a real-time video feed.

The tree frog's feet provide a solution to the critical problem of getting the device to hold onto wet, slippery tissue when it is vertical or upside down. Although it is relatively easy to find ways of sticking to or gripping tissue, the patterns on the frog's feet offer a way to hold and release a grip without harming the patient.

Lead researcher Professor Anne Neville, Royal Academy of Engineering Chair in Emerging Technologies at the University of Leeds, said: "Tree frogs have hexagonal patterned channels on their feet that when in contact with a wet surface build capillary bridges, and hence an adhesion force . It is the same kind of idea as a beer glass sticking to a beer mat, but the patterns build a large number of adhesion points that allow our robot to move around on a very slippery surface when it is upside down."

Professor Neville said: "To work effectively, this robot will have to move to all areas of the abdominal wall, turn and stop under control, and stay stable enough to take good quality images for the surgeons to work with.

"While basic capillary action works to an extent, the adhesion fails as soon as there is movement, so we have looked at the tiny mechanisms used in nature. It is only if you look at the scale of a thousandth of a millimetre, that you can get enough adhesion to give the robust attachment we need."

The frog-inspired robot has four feet -- each capable of holding a maximum of about 15 grams for each square centimetre in contact with a slippery surface. The researchers are aiming for a device that is 20×20×20mm, though they have been working on a prototype that is near double this size.

They are now trying to halve the size of their prototype so that it can fit through the incisions made during keyhole surgery. The prototype's weight is currently of the order of 20g and can be reduced much further.

 

 

Source: Science Daily

 

M.W

World's Melting Glaciers Making Large Contribution to Sea Rise

While 99 percent of Earth's land ice is locked up in the Greenland and Antarctic ice sheets, the remaining ice in the world's glaciers contributed just as much to sea rise as the two ice sheets combined from 2003 to 2009, says a new study led by Clark University and involving the University Colorado Boulder.

The new research found that all glacial regions lost mass from 2003 to 2009, with the biggest ice losses occurring in Arctic Canada, Alaska, coastal Greenland, the southern Andes and the Himalayas. The glaciers outside of the Greenland and Antarctic sheets lost an average of roughly 260 billion metric tons of ice annually during the study period, causing the oceans to rise 0.03 inches, or about 0.7 millimeters per year.

The study compared traditional ground measurements to satellite data from NASA's Ice, Cloud and Land Elevation Satellite, or ICESat, and the Gravity Recovery and Climate Experiment, or GRACE, missions to estimate ice loss for glaciers in all regions of the planet.

"For the first time, we've been able to very precisely constrain how much these glaciers as a whole are contributing to sea rise," said geography Assistant Professor Alex Gardner of Clark University in Worcester, Mass., lead study author. "These smaller ice bodies are currently losing about as much mass as the ice sheets."

A paper on the subject is being published in the May 17 issue of the journal Science.

"Because the global glacier ice mass is relatively small in comparison with the huge ice sheets covering Greenland and Antarctica, people tend to not worry about it," said CU-Boulder Professor Tad Pfeffer, a study co-author. "But it's like a little bucket with a huge hole in the bottom: it may not last for very long, just a century or two, but while there's ice in those glaciers, it's a major contributor to sea level rise," said Pfeffer, a glaciologist at CU-Boulder's Institute of Arctic and Alpine Research

ICESat, which ceased operations in 2009, measured glacier changes using laser altimetry, which bounces laser pulses off the ice surface to determine changes in the height of ice cover. The GRACE satellite system, still operational, detects variations in Earth's gravity field resulting from changes in the planet's mass distribution, including ice displacements.

GRACE does not have a fine enough resolution and ICESat does not have sufficient sampling density to study small glaciers, but mass change estimates by the two satellite systems for large glaciated regions agree well, the scientists concluded.

"Because the two satellite techniques, ICESat and GRACE, are subject to completely different types of errors, the fact that their results are in such good agreement gives us increased confidence in those results," said CU-Boulder physics Professor John Wahr, a study co-author and fellow at the university's Cooperative Institute for Research in Environmental Sciences.

 

Ground-based estimates of glacier mass changes include measurements along a line from a glacier's summit to its edge, which are extrapolated over a glacier's entire area. Such measurements, while fairly accurate for individual glaciers, tend to cause scientists to overestimate ice loss when extrapolated over larger regions, including individual mountain ranges, according to the team.

Current estimates predict if all the glaciers in the world were to melt, they would raise sea level by about two feet. In contrast, an entire Greenland ice sheet melt would raise sea levels by about 20 feet, while if Antarctica lost its ice cover, sea levels would rise nearly 200 feet.

Source: Science Daily

R.Sawas

Robotic insect: world's smallest flying robot makes first flight

 

Scientists at Harvard University have created a flying robot that can sit on a fingertip. Inspired by the biology of a fly, the robot is able to perform the agile movements of an insect.

Researchers at the Harvard School of Engineering and Applied Sciences (SEAS) put a decade's work into developing the penny-sized robot, before it took off for the first time.

Source: science daily

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