- Newly Discovered Chlorophyll Catches Infrared Light
- This Summer’s Sexiest Images From Saturn
- Galactic Supervolcano Erupts From Black Hole
- Focusing on Dark Energy With Cosmic Lens
- Gulf’s Depths Probably Still Clogged With Oil
- Massive North Atlantic Garbage Patch Mapped
- The Psychology of Nature
- Tiger Moths Scare Bats With Ultrasonic Clicks
- Stern Korean Culture Stifles Biological Predisposition to Blab
- Double-Whammy Earthquake Caused Tsunami
Posted: 20 Aug 2010 11:09 AM PDT
A new kind of chlorophyll that catches sunlight from just beyond the red end of the visible light spectrum has been discovered. The new pigment extends the known range of light that is usable by most photosynthetic organisms. Harnessing this pigment's power could lead to biofuel-generating algae that are super-efficient, using a greater spread of sunlight than thought possible.
"This is a very important new development, and is the first new type of chlorophyll discovered in an oxygenic organism in 60 years," says biological chemist Robert Blankenship of Washington University in St. Louis.
The newfound pigment, dubbed chlorophyll f, absorbs light most efficiently at a wavelength around 706 nanometers, just beyond the red end of the visible spectrum, researchers report online August 19 in Science. This unique absorbance appears to occur thanks to a chemical decoration known as a formyl group on the chlorophyll's carbon number two. That chemical tweak probably allows the algaelike organism that makes chlorophyll f to conduct photosynthesis while living beneath other photosynthesizers that capture all the other usable light.
"In nature this very small modification of the pigment happens, and then the organism can use this unique light," says molecular biologist Min Chen of the University of Sydney in Australia. Chen and her colleagues identified the new pigment in extracts from ground-up stromatolites, the knobby chunks of rock and algae that can form in shallow waters. The samples were collected in the Hamelin pool in western Australia's Shark Bay, the world's most diverse stromatolite trove.
Previously there were four known chlorophylls made by plants and other photosynthesizing organisms that generate oxygen: a, b, c and d. Chlorophyll a, the standard green type, is found in photosynthesizers from algae to higher plants. It absorbs mostly blue light around 465 nanometers and red light around 665 nanometers (it reflects green light, hence plants look green). Chlorophylls b and c are found in fewer organisms and absorb light in a similar range as chlorophyll a does, but shifted a bit. Chlorophyll d, found in a specific group of cyanobacteria, absorbs the most light at roughly 697 nanometers, a slightly shorter wavelength than the absorption of the new chlorophyll.
While some bacteria make chlorophyll-like pigments that absorb even longer wavelengths of light, these creatures aren't harnessing light to split water, the step in photosynthesis that generates oxygen. Scientists didn't think that wavelengths absorbed by chlorophyll f would have enough oomph to split water either, but it turns out they do, says Chen.
"This challenges our conception of the limit of oxygenic photosynthesis," she says.
The find may also enable scientists to engineer algae that are more efficient producers of oil for biofuels, says algae biologist Krishna Niyogi of the University of California, Berkeley. Microbes bearing the new chlorophyll could soak up rays that most microbes can't make use of.
There is still much to be learned about the new type of chlorophyll and the organisms that make it, Niyogi says. Chlorophyll f was extracted from the ground-up stromatolites along with a lot of chlorophyll a. It isn't clear what creature was making chlorophyll f, but evidence points to a filamentous cyanobacterium. This cyanobacterium might use both chlorophylls, or perhaps just f.
Images: 1) Red-shifting cyanobacteria./Science. 2) Shark Bay stromatolites./Wikimedia Commons.
Posted: 20 Aug 2010 04:00 AM PDT
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From a billion miles away, the Cassini spacecraft continues to send spectacular images of Saturn and its moons.
Cassini has been flying since 1997 and arrived at Saturn in 2004 after flybys of Earth, Venus and Jupiter. Its mission was originally slated to end in 2008, but it got its first 27 month extension to witness Saturn's equinox. This year, it was given another life extension until 2017 to keep exploring until Saturn's northern hemisphere summer solstice.
One of Cassini's main objectives going forward will be repeat flybys of Titan and Enceladus. Titan's atmosphere makes it one of the most Earth-like bodies in our solar system, and scientists are hoping to learn more about Encaledus' tectonic activity.
We've gathered twelve of Cassini's most impressive, mind-blowing shots from the last few months.
On the night side of Saturn, the planet casts a dark shadow over its rings. The moon Tethys can be seen in the upper right of the image, and the moon Enceladus is visible in the lower right. This image was taken May 30, 2010.
Image: NASA/JPL/Space Science Institute
Posted: 20 Aug 2010 02:00 AM PDT
Volcanic eruptions can wreak as much havoc in space as on Earth, a new image of galaxy M87 reveals. The black hole at the galaxy's center is spewing gas and energetic particles in what researchers call a "galactic supervolcano," and suppressing the formation of hundreds of millions of new stars.
The new photo shows clouds of gas that glow in X-ray light (blue) surrounding the galaxy from observations taken by the Chandra X-ray Observatory, and jets of radio emission (red) from observations from the Very Large Array of radio telescopes in New Mexico. Under normal circumstances, the hot gas would cool and fall toward the galaxy's center, ultimately congealing and igniting the birth of new stars.
But in M87, which lies about 50 million light-years away, jets of energetic particles produced by the galaxy's central black hole suppress the formation of new stars. The jets lift up the cooler gas near the center of the galaxy at supersonic speeds, producing shock waves in the galaxy's atmosphere. These plumes of gas contain as much mass as all the gas within 12,000 light-years of the center of the galaxy cluster M87 belongs to. All that gas could have turned into hundreds of millions of stars if the cosmic volcano had given it a chance, researchers say.
The researchers compare the galactic volcano in M87 to the Icelandic volcano Eyjafjallajokull, whose eruption this spring choked the sky with great clouds of ash and grounded planes across Europe. Eyjafjallajokull's eruption pushed pockets of hot gas through the surface lava, also producing shock waves that could be seen in the volcano's smoke. The hot gas then rose up in the atmosphere and dragged cool, dark ash with it, much like the energetic jets produced in the black hole lift cooler gas away from the galactic center.
"This analogy shows that even though astronomical phenomena can occur in exotic settings and over vast scales, the physics can be very similar to events on Earth," Stanford astrophysicist Aurora Simionescu, coauthor of a new study describing the cosmic eruption, said in a press release.
The analogy only goes so far, though. Evan Million, a grad student at Stanford and lead author of another study of M87's volcanic nature, points out that losing millions of stars' worth of gas "seems like a much worse disruption than what the airline companies on Earth had to put up with earlier this year."
More high-res images of M87 can be found on the Chandra observatory website.
Images: X-ray (NASA/CXC/KIPAC/N. Werner, E. Million et al); Radio (NRAO/AUI/NSF/F. Owen)
Posted: 19 Aug 2010 01:33 PM PDT
Our view of dark energy, the mysterious force that is shoving the universe apart, just got a little clearer. By observing the way large clumps of mass distort their local space-time into enormous cosmological lenses, astronomers have zoomed in on a quantity that describes how dark energy works.
"We have established the potency of a brand new technique to address this very fundamental problem," said astrophysicist Priyamvada Natarajan of Yale University, co-author of a paper in the Aug. 20 Science describing the new results. Combined with earlier experiments, the new results lead to significantly more accurate measurements of dark energy's properties, and could ultimately help explain what the bizarre stuff really is.
Dark energy was first proposed in 1998 to explain why the universe is expanding at an ever-increasing rate. Astronomers suggested that some kind of force, dubbed "dark energy" because of the shroud of mystery it hides in, works against gravity to push matter apart.
Although earlier experiments convinced astronomers the enigmatic stuff exists, not much else is known about it. Dark energy makes up the majority of the mass and energy in the universe, about 72 percent. Another 24 percent is thought to be dark matter, which is easier to study than dark energy because of its gravitational tugs on normal matter. The regular matter that makes up everything we can see, including atoms, stars, planets and people, comprises just 4 percent of the universe.
Dark energy also helps explain the geometry of the universe, and how the shape of the universe has changed over time. In the new study, Natarajan and her colleagues used Hubble Space Telescope images of a massive cluster of galaxies called Abell 1689 to get a clear view of the way space-time is shaped behind the cluster.
This galaxy cluster contains so much matter — both dark matter and the regular type — that light passing through it is distorted into long, stringy arcs. The cluster acts as a gigantic magnifying glass called a gravitational lens, and produces multiple, distorted images of the galaxies behind it.
For the first time, Natarajan said, "we were able to exploit this beautiful, clean phenomenon to characterize this lens so well that we could then map dark energy."
Natarajan and her colleagues carefully measured the way each image was distorted to determine how far the background galaxies were from the lens. They then combined that information with data on how far the galaxies are from Earth to come up with a parameter that describes the density of dark energy in the universe, and how the density changes with time.
"Knowing exactly where the object is, and knowing about the big lump that is causing the bumps in space-time, allows us to accurately calculate the light path," Natarajan said. "The light path depends on geometry of space-time, and dark energy manifests itself there. That's how we get at it."
This technique had been attempted before with a different cluster, but without much success. But because Abell 1689 is one of the most massive lenses around, it made more than 100 images of the galaxies behind it. "You want the oomphiest lens, the most massive, dramatic, extreme lens," Natarajan said. Abell 1689's extreme mass allowed the team to measure many more galaxies than ever before, and gave them a better picture of the cluster itself.
Natarajan hopes to apply the same technique to other massive clusters in the future. "What is fantastic about this technique is it's really rich," she said. "With just one cluster we can get a lot of stuff out. The prospects of applying this technique to many clusters, and to add to the statistical power, is very tantalizing."
"This method looks to be quite a promising addition to the cosmography toolkit," commented Stanford astrophysicist Phil Marshall, who was not involved in the new study. "It's impressive how well they do with just one cluster."
The results confirm what astronomers already thought they knew about dark energy, but with much greater accuracy, said study co-author Eric Jullo of NASA's Jet Propulsion Lab. The new measurements suggest that dark energy has had the same density for the entire history of the universe.
"That's weird," Jullo said. Imagine the universe as a balloon full of gas, he suggests. When the balloon gets bigger, the gas inside should spread out and get less dense. But dark energy seems to stay the same no matter how big the balloon is. "We don't know why this happens," he said. "That's why there is this race now, with many techniques and this one in particular, in trying to measure how dark energy density evolves with time."
Ultimately, astronomers will have to throw the kitchen sink at dark energy to figure out what it's made of. Every technique to measure dark energy has its own set of problems and errors. Using many different techniques can make each technique's shortcomings less important.
"The power is in combination," Natarajan said.
Posted: 19 Aug 2010 12:25 PM PDT
Oil released during the Deepwater Horizon disaster and suspended deep underwater appears to be breaking down more slowly than expected, suggests a new study. The greatest damage to the Gulf may ultimately be in the deep sea, rather than the shorelines — a catastrophe in a black box.
During the last two weeks of June, researchers from the Woods Hole Oceanographic Institute tracked a mile-long, 650-foot-thick plume of crude oil hydrocarbons as it oozed southwest of the blown well at a depth of about 3,000 feet. It was not the only such plume, nor necessarily the largest, but its behavior may give some indication of what is happening elsewhere. Much of the spilled oil, perhaps most, may share a similar fate.
Though unable to gauge precisely how quickly oil was breaking down, the researchers were able to measure the activity of microbes responsible for its decomposition. It's slow. And though the researchers autioned that the findings are just "a snapshot," a "first chapter," the results suggest that lots of oil is still in the Gulf, and will be there for a long time.
Published August 19 in Science, the findings come as the Deepwater Horizon's still-evolving legacy is a matter of both political and scientific controversy.
Not long after the blown well was capped on July 15th, after nearly five million barrels of oil had leaked, journalists were able to pose questions like, "Where is all the oil?" Hundreds of square miles of ocean surface had been covered, and hundreds of miles of shoreline fouled, but it still amounted to less than was expected.
Most of the public, however, interpreted the spill through a lens formed by shallow-water oil drilling, where spills float right to the surface. The dynamics of deep-sea spills, where hot oil shoots out into frigid water at extraordinary depth and pressure, are different.
For reasons still unknown, but hinted at in an obscure 2003 study and now made painfully clear, much of that oil doesn't float. It rises a bit, and hangs there. Hence reports during the disaster of giant, underwater oil plumes, which ultimately received less general attention than shoreline pollution, but was no less real.
In the disaster's aftermath, with the Obama administration announcing tight restrictions on deep-sea drilling and the oil industry fighting them, the federal National Oceanic and Atmospheric Administration released a report declaring that almost three-quarters of oil spilled into the Gulf was already gone (pdf). That conclusion was promptly attacked by oceanographers from the University of Georgia. Based on the same data, they said almost three-quarters of the oil was still there.
The difference was drastic, but relatively easy to explain. NOAA considered oil dissolved into the water or chemically dispersed as being gone. To the Geogia researchers, it was no more gone than sugar stirred into iced tea. Georgia ecologist Charles Hopkinson called the government "absolutely incorrect," saying "the oil is still out there, and it will likely take years to degrade. Soon after the Georgia team's declaration, researchers from the University of Florida reported finding oil in critical deep-water fish spawning grounds.
The WHOI team's Science data is the latest entry to this fight. Though they are careful to note the limitations of the data, gathered during two weeks in June by a remote vehicle programmed to follow oil, the findings are not encouraging.
Measurements of water oxygen levels — a proxy for the respiratory activity of microbes expected to decompose oil — found more activity than would be expected in oil-free water, but far less than would be found amidst surface oil. Some of the difference is expected because chemical reactions happen more slowly in the deep sea's colder environment. But even taking that into account, it was slower than predicted.
"Petroleum hydrocarbons did not fuel appreciable microbial respiration on the temporal scales of our study," wrote the researchers in Science. "It may require many months before microbes significantly attenuate the hydrocarbon plume."
The exact composition of the plume remains to be determined, but it does contain benzene, toluene, xylene and other compounds responsible for oil's toxicity.
"There is a huge unknown on the impact of these undersea plumes," said Carys Mitchelmore, a University of Maryland aquatic toxicologist. "We do not know what organisms are there," nor their tolerance to different concentrations of oil, nor how long those concentrations will remain, she said.
"It's easy to relate to an oiled pelican. It's harder to relate to an oiled copepod," said Georgia Aquarium ecologist Al Dove, who studies whale sharks in the Gulf of Mexico. "People get used to seeing images of oiled wildlife, birds on beaches, and that's a tragedy — but it's not what's going to keep the ecosystem from returning to what it was."
The Gulf's deep sea ecosystems have been studied far less than its shorelines, but it's possible that effects will ripple from one to the other.
"My experience is that what goes on in shallow water affects what goes on in the deep sea, and vice versa," said Craig McClain, a deep sea ecologist at the National Evolutionary Synthesis Center. "The interconnection is going to be really important, and we're only now getting a handle on it."
Studies of the oil's deep sea effects are just starting, and will continue for years. McClain said that data on deep sea life is far harder to gather and interpret than on coastlines, where animals can be easily counted and solid baseline data already exists.
"Those lower subsurface plumes could hang around for a while," said Mitchelmore. "There will be a black box of organisms dead out there."
Images: 1) Water visibility at descending depths./R. Camilli, WHOI. 2) Topographical map of plume location./R. Camilli, WHOI.
Citation: "Tracking Hydrocarbon Plume Transport and Biodegradation at Deepwater Horizon." By R. Camilli, C. Reddy, D. Yoerger, B. Van Mooy, J. Kinsey, C. McIntyre, S. Sylva, M. Jakuba, J. Maloney. Science, Vol. 329 No. 5994, August 19, 2010.
Posted: 19 Aug 2010 12:16 PM PDT
Millions of pieces of plastic — most smaller than half an inch — float throughout the oceans. They are invisible to satellites, and except on very calm days you won't even see them from the deck of a sailboat. The only way to know how much junk is out there is to tow a fine net through the water.
Scientists have gathered data from 22 years of surface net tows to map the North Atlantic garbage patch and its change over time, creating the most accurate picture yet of any pelagic plastic patch on earth.
The data were gathered by thousands of undergraduates aboard the Sea Education Association (SEA) sailing semester, who hand-picked, counted and measured more than 64,000 pieces of plastic from 6,000 net tows between 1986 to 2008.
"The highest concentrations that we observe in the North Atlantic garbage patch are comparable to that of the North Pacific, but we don't have enough data about the size of the North Pacific one to say whether they are comparable in size," said oceanographer Kara Law of SEA, lead author of the study published August 19 in Science.
"As far as I'm aware this is the most complete and long term data set for little bits of trash floating in the ocean," said oceanographer Miriam Goldstein of Scripps Institution of Oceanography. "It is hard to get long term data sets of the ocean, there aren't many programs that do it, and measure it the same way from year to year so you can compare the changes over time."
The highest concentrations of plastic were found roughly from the latitude of Virginia to the latitude of Cuba. While they were able to clearly define the north and south boundaries of the patch, the cruise tracks didn't venture far enough east to find the eastern boundary. They estimate the average concentration of plastic in this area is about 4,000 pieces per square mile, though it is as high as 250,000 pieces per square mile in some places.
To determine where the plastic is coming from, researchers used data from more than 1,600 satellite-tracked drifting buoys deployed between 1989 and 2009 to map surface currents in the region. More than 100 buoys passed through the Atlantic plastic region, most originating from the eastern seaboard. In most cases, the buoys reached the plastic patch in less than 60 days.
Plastic accumulated in regions called gyres, where currents circle and push water toward the center, trapping the floating bits. There are five major gyres in the the world, one in each major ocean.
To estimate the range and highest accumulation of plastic in the North Atlantic and elsewhere, the research team created a computer model to simulate where plastic would go over time if it originally had been distributed evenly across the planet (image above).
"We saw very high concentrations of plastic in the model in the Atlantic in the same places we observed the plastic directly," Law said. She hopes the computer model will help target future efforts to map plastic in the oceans.
One surprising conclusion of the study found the concentration of plastic in the North Atlantic has remained fairly steady during the past 22 years despite a five-fold increase in global plastic production and a four-fold increase in the amount of plastic the United States discards.
"If you are increasing the amount you put in, you'd theoretically be seeing more over time," said Law. "It makes you ask other questions about the fact that the plastic might be sinking out. I'm also fairly certain that the pieces are breaking down into pieces that are smaller than the 335 micron (0.01 inch) size of our net."
Optimistically, the study found a 1991 program by the Environmental Protection Agency to recapture industrial plastic pellets led to a significant decrease in the average number of pellets found in the Atlantic. The pellets account for less than 10 percent of the plastic out there, but the finding suggests efforts to reduce plastic waste on land can be effective.
No one knows how long plastic stays in the ocean or where most of it ultimately will end up. Sea animals such as birds and turtles often consume plastic, sometimes carrying it to land. Some likely will sink over time or wash up on shore.
"Cleaning up what is out there is really not feasible, and would likely cause as much harm as good because of all the other small creatures in the ocean that would get filtered out too," said Law. "So what's left is hoping that nature break this plastic down over hundreds of years or millenia."
"Ultimately, we need to prevent adding to what is out there," she added.
Images: 1) Skye Moret/SEA. 2) Image courtesy of Science/AAAS. 3) Nikolai Maximenko/ University of Hawii. 4) Flickr/angrysunbird.
Posted: 19 Aug 2010 10:09 AM PDT
In the late 1990s, Frances Kuo, director of the Landscape and Human Health Laboratory at the University of Illinois, began interviewing female residents in the Robert Taylor Homes, a massive housing project on the South Side of Chicago. Kuo and her colleagues compared women randomly assigned to various apartments. Some had a view of nothing but concrete sprawl, the blacktop of parking lots and basketball courts. Others looked out on grassy courtyards filled with trees and flowerbeds. Kuo then measured the two groups on a variety of tasks, from basic tests of attention to surveys that looked at how the women were handling major life challenges. She found that living in an apartment with a view of greenery led to significant improvements in every category.
What happened? Kuo argues that simply looking at a tree "refreshes the ability to concentrate," allowing the residents to better deal with their problems. Instead of getting flustered and angry, they could stare out the window and relax. In other words, there is something inherently "restorative" about natural setting – places without people are good for the mind.
To better understand how nature works its psychological magic, let's look at an important 2008 study led by Marc Berman, at the University of Michigan. (I've written about this study before.) Berman and colleagues outfitted undergraduates at the University of Michigan with GPS receivers. Some of the students took a stroll in an arboretum, while others walked around the busy streets of downtown Ann Arbor.
The subjects were then run through a battery of psychological tests. People who had walked through nature were in a better mood and scored significantly higher on a test of attention and working memory, which involved repeating a series of numbers backwards. In fact, just glancing at a photograph of nature led to measurable improvements, at least when compared with pictures of city streets.
Does this mean we should all flee the city? Of course not. It simply means that it's a good idea to build a little greenery into our life. This isn't a particularly new idea.Long before scientists fretted about the cognitive load of city streets, philosophers and landscape architects were warning about the effects of the undiluted city, and looking for ways to integrate nature into modern life. Ralph Waldo Emerson advised people to "adopt the pace of nature," while the landscape architect Frederick Law Olmsted sought to create vibrant urban parks, such as Central Park in New York and the Emerald Necklace in Boston, that allowed the masses to escape the maelstrom of urban life. (As Berman told me, "It's not an accident that Central Park is in the middle of Manhattan…They needed to put a park there.")
Although Olmsted took pains to design parks with a variety of habitats and botanical settings, most urban greenspaces are much less diverse. Instead, the typical city park is little more than an expansive lawn, punctuated by a few trees and playing fields. I've got nothing against grass and Little League, but it's probably worth pointing out that, if you want to maximize the psychological perks of greenspace, this is probably the wrong approach.In a 2007 paper, Richard Fuller, an ecologist at the University of Queensland, demonstrated that the mental benefits of green space are closely linked to the diversity of its plant life. When a city park has a larger variety of trees, subjects that spend time in the park score higher on various measures of psychological well-being, at least when compared with less biodiverse parks.
Over at Scienceline, Ferris Jabr has an excellent article on the recent attempts to turn ecopsychology into a rigorous science. He describes an interesting new experiment led by Peter Kahn:
I sometimes wonder if, when we look back at the mass cognitive mistakes of the 21st century, we'll worry less about the internet and multitasking – people have been multitasking forever – and instead fret about our turn away from nature. The human species is urbanizing at an unprecedented rate. (In the next century, at least 3 billion people will migrate to cities.) And yet, we're only beginning to understand how living in dense agglomerations of perfect strangers, surrounded by skyscrapers and concrete, actually effects the brain. This work on ecopsychology is an important start.
Image: From my recent trip to the Grand Tetons. This view restored my PFC.
Posted: 19 Aug 2010 09:30 AM PDT
It's kinda tough being a moth. Not only do you have to go through the icky process of pupating, but you're also the favorite food of bats, which use ultrasonic echolocation to swoop down and pounce on you when you're just trying to have some fun, flapping around a lightbulb.
But one species, Cycnia tenera, which is known to its friends as the Toxic Dogbane Tiger Moth, has evolved special bat-detecting ears that contain neurons sensitive to the frequencies used by the bats for their echolocation clicks. Not only that, but the moth has even worked out how to generate ultrasonic pulses itself, confusing the bat into aborting the attack.
In an Aug. 18 Proceedings of the Royal Society B study, the group put moths in a dark chamber covered with sound insulation, played them the sounds of a bat's echolocation calls, and recorded their responses with a microphone. The recordings were then analyzed to find out how the moths react to the bats.
Posted: 19 Aug 2010 07:32 AM PDT
Stressed-out Americans tend to vent. They talk about their troubles, and call up their friends for validation. Most Koreans, on the other hand, would rather keep it to themselves.
According to a new study, that difference between European American and Korean customs is so powerful that it shapes the expression of biology: A genetic profile linked to empathy and sociability yields two very different behavioral outcomes, depending on the culture.
Other studies have described how the interaction of traumatic events and genes can influence a person's risk for schizophrenia or other psychological disorders. But "environment" is more than disasters and childhood experience.
"We're trying to broaden the notion of environment [away] from risk factors in your personal life," said Heejung Kim, a social psychologist at the University of California-Santa Barbara. "We wanted to see … about a shared environment, and started to look at the role of culture."
In the new study, published Aug. 16 in the Proceedings of the National Academy of Sciences, Kim's team looked at the relationship between culture and a gene called OXTR. The gene encodes a receptor for the hormone oxytocin, renowned for its ability to promote social bonding. OXTR comes in two versions, G and A.
In Western cultures, people with at least one G version of the gene tend to be more sensitive parents, less lonely, more empathic, and have lower rates of autism than people with the A version.
Kim's team reasoned that, among European Americans, social G people would be more likely than A people to go to friends and family for emotional support during tough times. Kim's survey of 140 European American adults, published online this week in Proceedings of the National Academy of Sciences, confirmed that prediction.
In Korea, though, even having the social G version of OXTR didn't prompt people to talk about their feelings. In fact, a survey of 134 Koreans hinted at just the opposite: Stressed Koreans with the G version were the most reluctant to seek social support.
Kim thinks that's because the more social and empathic G types are closely attuned to their cultural norms — which, in Korea, dictate that one doesn't share one's problems.
"Asian cultures are collectivistic cultures. You have to care what people think of you a lot more," Kim said. "So by seeking emotional support you're disclosing your problems to … others. You might make that person get worried. You might have to worry about embarrassing yourself to other people."
That's still speculation — but it might explain how the same version of the same gene can give rise to venting in one culture, but are bottled in another.
Korean Americans had the same patterns of expression as European Americans, reducing the possibility that other unstudied Korean genes are causing the difference.
"This [study] is really breaking new ground," said Joan Chiao, a cultural neuroscientist at Northwestern University who studies how culture affects human behavior. It's one of the first to show that cultural norms themselves are environmental factors that interact with genes, said. That brings together two branches of science that have a long history of separation.
"We're making really important concrete steps toward bridging [gaps between] culture and biological sciences," Chiao says. "That's going to ultimately pay off in our understanding of physical and mental health factors that we all care about."
Photo: Jim Merithew/Wired.com
Citation: "Gene-culture interaction: Effects of culture, distress, and oxytocin receptor polymorphism on emotional support seeking." By Heejung S. Kim, David K. Sherman, Joni Y. Sasaki, Jun Xu, Thai Q. Chu, Chorong Ryu, Eunkook M. Suh, Kelsey Graham, Shelley E. Taylor. Proceedings of the National Academy of Sciences, Vol. 107. No. 34, August 17, 2010.
Posted: 19 Aug 2010 03:00 AM PDT
A giant earthquake that triggered a deadly southwest Pacific tsunami was actually two great temblors, finds a pair of new studies in the Aug. 19 Nature. These results uncover an unusual sequence of geological events that is the first of its kind to be observed by scientists, the study authors say.
The earthquakes, which likely struck within two minutes of each other on Sept. 29, 2009, spawned a tsunami that killed nearly 200 people in Samoa, American Samoa and Tonga. Scientists assumed that a single quake under the ocean floor had caused the devastation, but the pattern of far-flung aftershocks, aberrant tsunami waves and the inexplicable movement of a Tongan island cast doubt on that simple explanation.
"We knew right off the bat that something was weird about this earthquake," says geophysicist Eric Geist of the U.S. Geological Survey in Menlo Park, California. Geist wasn't involved in the current studies but has puzzled over the anomalous signs produced by the quake. "This is a very complicated event, and these studies, for me, really helped explain a lot."
The earthquake that everybody knew about was a whopper: a magnitude-8.1 quake in which the ground was pulled apart along a fault. The hidden quake was a different type. It happened about 70 kilometers from its predecessor on a thrust fault where the west-moving Pacific plate dives under the east-bound Tonga block of the Australia plate, an event called subduction. These two plates scrape past each other 24 centimeters each year, "the fastest plate tectonics on the planet," says study co-author John Beavan of GNS Science in Lower Hutt, New Zealand.
A magnitude-8.1 quake in the southwest Pacific triggered a second quake, comprised of two magnitude-7.8 subevents, where the east-moving Tonga block of the Australia plate meets the west-moving Pacific plate.
The two research teams separately uncovered the presence of a second earthquake using different data. Beavan and his colleagues found that tsunami gauges on the ocean floor measured a big positive pressure wave, a suspicious sign since a ground-extending earthquake would cause a drop in pressure.
Another big clue came from GPS stations on the northern Tongan island of Niuatoputapu, which has been steadily moving east. On its own, the first earthquake would have sent the island slightly back to the west. But instead, the island jumped about 40 centimeters to the east. "It was completely out of kilter," Beavan says. The best explanation was that a second thrusting fault earthquake had caused the motion.
The other research group, led by seismologist Thorne Lay of the University of California, Santa Cruz, spotted abnormalities in seismic data that led them to dig deeper into the seismic records.
"We were able to pull together a self-consistent story of the triggered thrust earthquake, and clearly it was as big as the first event," Lay says. "It was a magnitude-8 hidden earthquake. And you would think, 'Well, aren't seismologists a bunch of idiots. They can't even find a magnitude-8 earthquake,' but it was obscured by the strong shaking from the first one."
Lay and his team built a model in which the normal fault earthquake happened first, triggering the hidden thrust-fault quake, Lay says. Beavan's team's study didn't have the resolution to parse the timing of the earthquakes, but he says that he suspects Lay and his colleagues' time line is correct.
Both studies peg the second earthquake at a magnitude 8.0. Lay and his colleagues were able to distinguish two distinct but nearly simultaneous energy releases from the second earthquake, which they call subevents. Each of these subevents, they estimate, was magnitude 7.8, which combined to hit the 8.0 mark.
"We pretty well understand what's going on with these earthquakes," Beavan says. "The fact that these two studies, which use completely different techniques, both come up with the same answer is really nice."
Understanding all of the forces involved may be useful in building better models of how earthquakes can trigger one another and tsunamis. This is the first example of a normal fault earthquake setting off a thruster fault quake, Geist says, which "will set off a lot of interesting research on the mechanics of subduction zones and how they behave."
Images: 1) Flickr/madaboutasia. 2) Mick Finn/GNS Science
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