Wednesday, May 12, 2010

UNDERWATER ASPHALT VOLCANOES DISCOVERED BY UCSB SCIENTISTS

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About 10 miles off the Santa Barbara coast, at the bottom of the Santa Barbara Channel, a series of impressive landmarks rise from the sea floor. They've been there for about 40,000 years, but they've remained hidden in the murky depths of the Pacific Ocean –– until now.

UC Santa Barbara scientists, working with colleagues from Woods Hole Oceanographic Institution (WHOI), UC Davis, University of Sydney, and University of Rhode Island, say that they have identified a series of asphalt volcanoes on the floor of the Santa Barbara Channel. The largest of these undersea Ice Age domes is at a depth of 700 feet (220 meters) –– much too deep for scuba diving –– which explains why the volcanoes have never been spotted by humans.

"It's larger than a football field long and as tall as a six-story building," said David Valentine, professor of earth science at UCSB and the lead author of a National Science Foundation-funded study published online this week in the journal Nature Geoscience. "It's a massive feature, completely made out of asphalt."

Chris Reddy, director of the Coastal Ocean Institute at WHOI and a co-author of the study, has studied oil spills his whole career. "These volcanoes are an astonishing display of nature," Reddy said. "And they underscore one little-known fact: Half of the oil that enters the coastal environment is from natural oil seeps like the ones off the coast of California."

Valentine, Reddy, and their colleagues first viewed the volcanoes during a 2007 dive on the research submarine Alvin, though Valentine credits Ed Keller, professor of earth science at UCSB, with guiding them to the site. "Ed had looked at some bathymetry (sea floor topography) studies conducted in the 1990's and noted some very unusual features," Valentine said.

Based on Keller's research, Valentine and other scientists took Alvin into the area in 2007 and located the mystery features. Using the sub's robotic arm, the researchers broke off samples and brought them to labs at UCSB and WHOI for testing. In 2009, Valentine and colleagues made two more dives to the area in Alvin and also did a detailed survey of the area using an autonomous underwater vehicle, Sentry, which takes photos as it glides about nine feet above the ocean floor.

"When you fly Sentry over the sea floor, you can see all of the cracking of the asphalt and flow features," Valentine said. "You can see all of the textures of a flowing liquid that solidified in place. That's one of the reasons we're calling them volcanoes, because they have so many features that are indicative of a lava flow."

But tests showed that these aren't your typical lava volcanoes found in Hawaii and elsewhere around the Pacific Rim. Using a mass spectrometer, carbon dating, microscopic fossils, and comprehensive, two-dimensional gas chromatography, the scientists determined that these are asphalt and were formed when petroleum was flowing from the floor of the channel about 30,000-40,000 years ago.

The researchers also determined that the volcanoes were at one time a prolific source of methane, a greenhouse gas. The two largest volcanoes are about a kilometer apart and have pits or depressions surrounding them. These pits, according to Valentine, are signs of "methane gas bubbling from the subsurface." That's not surprising, Valentine said, considering how much petroleum was flowing. "They were spewing out a lot of petroleum, but also lots of natural gas," he said, "which you tend to get when you have petroleum seepage in this area."

The discovery that vast amounts of methane once emanated from the volcanoes caused the scientists to wonder if there might have been an environmental impact on the area during the Ice Age. Valentine found two high-profile studies, one in the journal Science and the other in the Proceedings of the National Academy of Sciences, which examined events from that time, including a period in which water in the channel became anoxic. "It became a dead zone," Valentine said. "We're hypothesizing that these features may have been a major contributor to those events."

While the volcanoes have been dormant for thousands of years, the 2009 Alvin dive revealed a few spots where gas was still bubbling. "We think it's residual gas," said Valentine, who added that the amount of gas is so small that it is harmless because it never reaches the surface.

(Photo: George Foulsham Office of Public Affairs)

University of California, Santa Barbara

BRAINS, WORMS, AND COMPUTER CHIPS HAVE STRIKING SIMILARITIES

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An international team of scientists has discovered striking similarities between the human brain, the nervous system of a worm, and a computer chip. The finding is reported in the journal PloS Computational Biology.

"Brains are often compared to computers, but apart from the trivial fact that both process information using a complex pattern of connections in a physical space, it has been unclear whether this is more than just a metaphor," said Danielle Bassett, first author and a postdoctoral research associate in the Department of Physics at UC Santa Barbara.

The team of scientists from the U.S., the U.K., and Germany has uncovered novel quantitative organizational principles that underlie the network organizations of the human brain, high performance computer circuits, and the nervous system of the worm, known as nematode C. elegans. Using data that is largely in the public domain, including magnetic resonance imaging data from human brains, a map of the nematode's nervous system, and a standard computer chip, they examined how the elements in each system are networked together.

They found that all three shared two basic properties. First, the human brain, the nematode's nervous system, and the computer chip all have a Russian doll-like architecture, with the same patterns repeating over and over again at different scales.

Second, all three showed what is known as Rent's scaling, a rule used to describe the relationship between the number of elements in a given area and the number of links between them.

Worm brains may seem to have very little in common with human brains and even less in common with computer circuits, explained Bassett. In fact, each of these systems contains a pattern of connections that are locked solidly in a physical space, similar to how the tracks in a railway system are locked solidly to the ground, forming traffic paths that have fixed GPS coordinates. A computer chip starts out as an abstract connectivity pattern, which can perform a specific function. Stage two involves mapping that connectivity pattern onto the two-dimensional surface of the chip. This mapping is a key step and must be done carefully in order to minimize the total length of wires –– a powerful predictor of the cost of manufacturing a chip –– while maintaining the abstract connectivity or function.

"Brains are similarly characterized by a precise connectivity which allows the organism to function, but are constrained by the metabolic costs associated with the development and maintenance of long ‘wires,' or neurons," said Bassett. She explained that, given the similar constraints in brains and chips, it seems that both evolution and technological innovation have developed the same solutions to optimal mapping patterns.

She explained that this scaling result may further explain a well-known but little-understood relationship between the processing elements (neuronal cell bodies, or gray matter) and wiring (axons, or white matter) in the brains of a wide range of differently sized mammals –– from mouse to opossum to sea lion –– further suggesting that these principles of nervous system design are highly conserved across species.

This work suggests that market-driven human invention and natural selection have negotiated trade-offs between cost and complexity in designing both types of information processing network: brains and computer circuits.

Bassett worked closely with Edward Bullmore, professor of psychiatry at the University of Cambridge. He explained: "These striking similarities can probably be explained because they represent the most efficient way of wiring a complex network in a confined physical space –– be that a three-dimensional human brain or a two-dimensional computer chip."

(Photo: George Foulsham, Office of Public Affairs, UCSB)

University of California, Santa Barbara

RESEARCH AT ANTARCTICA'S 'MARS ON EARTH' REVEALS NON-ORGANIC MECHANISM FOR PRODUCTION OF IMPORTANT GREENHOUSE GAS

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In so many ways, Don Juan Pond in the Dry Valleys of Antarctica is one of the most unearthly places on the planet. An ankle-deep mirror between mountain peaks and rubbled moraine, the pond is an astonishing 18 times saltier than the Earth’s oceans and virtually never freezes, even in temperatures of more than 40 degrees below zero Fahrenheit.

Now, a research team led by biogeochemists from the University of Georgia has discovered at the site a previously unreported chemical mechanism for the production of nitrous oxide, an important greenhouse gas. Possibly even more important, the discovery could help space scientists understand the meaning of similar brine pools in a place whose ecosystem most closely resembles that of Don Juan Pond: Mars.

The research, published April 25 in the journal Nature Geoscience, adds an intriguing new variable to growing evidence that there has been—and may still be—liquid water on Mars, a usual prerequisite for the formation of life. In fact, the new findings could help space scientists develop sensors for detecting such brines on Mars—thus narrowing the search for places where life may exist.

“The pond’s soils and brines and the surrounding rock types are similar to those found on Mars,” said Samantha Joye, a faculty member in the department of marine sciences in the Franklin College of Arts and Sciences and lead author on the paper. “So it provides an ideal location to assess microbial activity in extreme environments. While we did not detect any ‘bio-gases’ such as hydrogen sulfide and methane, we did, surprisingly, measure high concentrations of nitrous oxide, which is normally an indicator of microbial activity. We needed to find out whether a non-organic process could account for this nitrous oxide production.”

Other authors on the paper include Vladimir Samarkin, a research scientist, and Marshall Bowles, a graduate student, also of the department of marine sciences at UGA; Michael Madigan of Southern Illinois University; Karen Casciotti of the Woods Hole Oceanographic Institution; John Priscu of Montana State University; and Christopher McKay of the Ames Research Center of NASA.

The research was supported by grants from the National Science Foundation’s Antarctic Organisms and Ecosystems Program and the McMurdo Microbial Observatory Program.

Scientists have been fascinated with Don Juan Pond since its discovery in 1961. (While the site is lovely, there’s nothing romantic about the name, which comes from the helicopter pilots who first found it, Don Roe and John Hickey.) From the time of its discovery, researchers realized they had found a place like nowhere else on Earth.

The pond, which is a roughly 1,000- by 400-meter basin, is the saltiest body of water on Earth by far, some eight times saltier than the Dead Sea. While researchers more than 30 years ago reported finding abundant and varied microflora of fungi, bacteria, blue-green algae and yeasts, since then and during the Joye team’s work, such life has been non-existent. Since the depth level and area covered by the pond (which is fed by hypersaline groundwater) have demonstrably varied over the years, this wasn’t unexpected. What did surprise the team was that even with no life-forms present, they were able to measure nitrous oxide, perhaps best known to most people as the “laughing gas” used in dental procedures. (The amounts measured in the air were beneath a level that could make a person light-headed or giddy, as “laughing gas” can.)

“What we found was a suite of brine-rock reactions that generates a variety of products, including nitrous oxide and hydrogen,” said Joye. “In addition to Don Juan Pond, this novel mechanism may occur in other environments on Earth as well and could serve as both an important component of the Martian nitrogen cycle and a source of fuel [hydrogen] to support microbial chemosynthesis.”

Even more interesting, perhaps, is that the results suggest that an additional mechanism—the reaction of brine-derived nitrates with basaltic rock—could be a “previously unrecognized means for mobilizing nitrate from the surface soils . . . and returning it to the Martian atmosphere as nitrous oxide,” Joye said.

The discovery of water has been the holy grail of numerous Mars missions over the years, and in 2009 the Mars Phoenix mission’s cameras photographed on the legs of the lander what appeared to be liquid water. If ultimately confirmed—and growing evidence appears to be solidifying in favor of such an analysis—it would be the first time liquid water was detected and photographed outside the Earth.

Working in such a beautiful but unearthly area presents stern challenges to researchers, Joye said.

“It’s a 40-minute helicopter ride over the McMurdo Sound just to get there,” she said. “Once in the Wright Valley, we enter a tight enclosure with steep, rocky cliffs on both sides, and between them is Don Juan Pond. I believe it must be one of the most beautiful places in Antarctica.”

Samarkin agreed.

“It has the kind of beauty that rock parks in Japan have,” he said, “except this is made by nature.”

Beauty aside, though, the team had to dress in sterile suits and masks and use sterile instruments for sampling to avoid possible contamination. They also collected the minimal amount of material necessary to achieve their research goals.

The discovery of the new mechanism opens numerous questions that must be studied, including the possibility that the process is taking place in other extreme Antarctic habitats or that it might contribute to nitrous oxide in temperate soils—a possible new clue to understanding greenhouse gases involved in global warming.

The most crucial result, however, may be in understanding how similar brine pools on Mars might work and whether they could support life.

(Photo: U. Georgia)

University of Georgia

STEM CELLS FROM SURGERY LEFTOVERS COULD REPAIR DAMAGED HEARTS

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Scientists have for the first time succeeded in extracting vital stem cells from sections of vein removed for heart bypass surgery. Researchers funded by the British Heart Foundation (BHF) found that these stem cells can stimulate new blood vessels to grow, which could potentially help repair damaged heart muscle after a heart attack.

The research, by Paolo Madeddu, Professor of Experimental Cardiovascular Medicine and his team in the Bristol Heart Institute (BHI) at the University of Bristol, is published in the leading journal Circulation.

Around 20,000 people each year undergo heart bypass surgery. The procedure involves taking a piece of vein from the person’s leg and grafting it onto a diseased coronary artery to divert blood around a blockage or narrowing.

The surgeon normally takes out a longer section of vein than is needed for the bypass. The Bristol team successfully isolated stem cells from leftover veins that patients had agreed to donate.

In tests in mice, the cells proved able to stimulate new blood vessels to grow into injured leg muscles. Professor Madeddu and his team are now beginning to investigate whether the cells can help the heart to recover from a heart attack.

“This is the first time that anyone has been able to extract stem cells from sections of vein left over from heart bypass operations,” Professor Madeddu said. “These cells might make it possible for a person having a bypass to also receive a heart treatment using their body’s own stem cells.

“We can also multiply these cells in the lab to make millions more stem cells, which could potentially be stored in a bank and used to treat thousands of patients.”

Professor Peter Weissberg, Medical Director of the BHF, said: “Repairing a damaged heart is the holy grail for heart patients. The discovery that cells taken from patients’ own blood vessels may be able to stimulate new blood vessels to grow in damaged tissues is a very encouraging and important advance. It brings the possibility of ‘cell therapy’ for damaged hearts one step closer and, importantly, if the chemical messages produced by the cells can be identified, it is possible that drugs could be developed to achieve the same end.”

(Photo: Bristol U.)

University of Bristol

CSIRO TELESCOPE SPOTS MEGA-STAR CRADLE

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Using a CSIRO radio telescope, an international team of researchers has caught an enormous cloud of cosmic gas and dust in the process of collapsing in on itself – a discovery which could help solve one of astronomy’s enduring conundrums: ‘How do massive stars form?’

Dr Peter Barnes from the University of Florida says astronomers have a good grasp of how stars such as our Sun form from clouds of gas and dust, but for heavier stars – ten times the mass of the Sun or more – they are still largely in the dark, despite years of work.

“Astronomers are still debating the physical processes that can generate these big stars,” Dr Barnes says.

“Massive stars are rare, making up only a few per cent of all stars, and they will only form in significant numbers when really massive clouds of gas collapse, creating hundreds of stars of different masses. Smaller gas clouds are not likely to make big stars.”

Accordingly, regions in space where massive stars seem to be forming are also rare. Most are well over 1000 light-years away, making them hard to observe.

Using CSIRO’s ‘Mopra’ radio telescope – a 22m dish near Coonabarabran, NSW – the research team discovered a massive cloud of mostly hydrogen gas and dust, three or more light-years across, that is collapsing in on itself and will probably form a huge cluster of stars.

Dr Stuart Ryder of the Anglo-Australian Observatory said the discovery was made during a survey of more than 200 gas clouds.

“With clouds like this we can test theories of massive star cluster formation in great detail.”

The gas cloud, called BYF73, is about 8,000 light years away, in the constellation of Carina (“the keel”) in the Southern sky.

Evidence for ‘infalling’ gas came from the radio telescope’s detection of two kinds of molecules in the cloud – HCO+ and H13CO+. The spectral lines from the HCO+ molecules in particular showed the gas had a velocity and temperature pattern that indicated collapse.

Mopra Research Scientist at CSIRO Astronomy and Space Science, Dr Kate Brooks, said the Mopra telescope excels at giving a picture of the complex chemistry of cosmic gas clouds.

“Much of its time is used for large projects like this, and almost all Mopra projects are international collaborations.”

The CSIRO telescope observations were confirmed by observations with the Atacama Submillimeter Telescope Experiment (ATSE) telescope in Chile.

The research team calculates that the gas is falling in at the rate of about three per cent of the Sun’s mass every year – one of the highest rates known.

Follow-up infrared observations made with the 3.9-m Anglo-Australian Telescope (also near Coonabarabran, NSW) showed signs of massive young stars that have already formed right at the centre of the gas clump, and new stars forming.

Star-formation in the cloud was also evident in archival data from the Spitzer and MSX spacecraft, which observe in the mid-infrared.

Gas cloud BYF73 was found during a large-scale search for massive star-forming regions – the Census of High- and Medium-mass Protostars, or CHaMP. This is one of the largest, most uniform and least biased surveys to date of massive star-forming regions in our Galaxy.

(Photo: NASA/JPL-Caltech)

CSIRO

MASSIVE SOUTHERN OCEAN CURRENT DISCOVERED

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A deep ocean current with a volume equivalent to 40 Amazon Rivers has been discovered by Japanese and Australian scientists near the Kerguelen plateau, in the Indian Ocean sector of the Southern Ocean, 4,200 kilometres south-west of Perth.

In a paper published in Nature Geoscience, the researchers described the current –more than three kilometres below the Ocean’s surface – as an important pathway in a global network of ocean currents that influence climate patterns.

“The current carries dense, oxygen-rich water that sinks near Antarctica to the deep ocean basins further north,” says co-author Dr Steve Rintoul from the Antarctic Climate and Ecosystems CRC and CSIRO’s Wealth from Oceans Flagship.

“Without this supply of Antarctic water, the deepest levels of the ocean would have little oxygen.

“The ocean influences climate by storing and transporting heat and carbon dioxide – the more the ocean stores, the slower the rate of climate change. The deep current along the Kerguelen Plateau is part of a global system of ocean currents called the overturning circulation, which determines how much heat and carbon the ocean can soak up.”

While earlier expeditions had detected evidence of the current system, they were not able to determine how much water the current carried. The joint Japanese-Australian experiment deployed current-meter moorings anchored to the sea floor at depths of up to 4500m. Each mooring reached from the sea floor to a depth of 1000m and measured current speed, temperature and salinity for a two-year period.

“The continuous measurements provided by the moorings allow us, for the first time, to determine how much water the deep current carries to the north,” Dr Rintoul said. The current was found to carry more than 12 million cubic metres per second of Antarctic water colder than 0 °C (because of the salt dissolved in sea water, the ocean does not freeze until the temperature gets close to -2 °C).

“It was a real surprise to see how strong the flow was at this location. With two-year average speeds of more than 20cm per second, these are the strongest mean currents ever measured at depths three kilometres below the sea surface.

“Mapping the deep current systems is an important step in understanding the global network of ocean currents that influence climate, now and in the future. Our results show that the deep currents near the Kerguelen Plateau make a large contribution to this global ocean circulation,” Dr Rintoul said.

Antarctic waters carried northward by the deep currents eventually fill the deep layers of eastern Indian and Pacific Oceans.

(Photo: CSIRO)

CSIRO

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