- Antarctic Ice Core Research Requires Logistical High-Wire Act
- Rampaging Hot Jupiters May Keep Earthlike Planets Out of Their Systems
- DNA Testing Finds Endangered Whale Meat in Restaurants
Posted: 13 Apr 2010 03:02 PM PDT
Two freezers full of carefully diced and labeled ice drilled from the Antarctic peninsula were hoisted aboard the Nathaniel B. Palmer research vessel Sunday for a trip that will eventually end in Columbus, Ohio.
Getting valuable scientific evidence from a hole in the ice near the south pole to the Midwest is as dramatic as logistics can get. Researchers and their ice samples somehow survive harsh conditions in tiny planes, aboard icebreakers, inside hastily assembled geodesic domes, and in refrigerator trucks.
And it all has to go just right because researchers like paleoclimatologist Ellen Mosley-Thompson at the Ohio State University only get a few chances to secure the data they need to reconstruct the climate record for an area.
"We wanted to [drill this ice core] starting in the mid-90s and it's taken us 15 years to do it," Mosley-Thompson said. "It's just a very challenging place to work. Logistics are hard, and it's expensive."
Earlier this year, her team got funding from the National Science Foundation through the LARISSA project to execute their plan to drill in the peninsula.
Data extracted from ice cores is a key piece of climatological evidence. Scientists use them as proxy data to determine determine what the temperature, precipitation patterns, atmospheric chemistry, and solar variability of an area were in the past. For example, looking at layer after layer, they could reconstruct a sea ice record for a given year based on the amount of certain salts and methanesulfonic acid in the cores.
In this case, specifically, Mosley-Thompson is interested in the relationship between inland Antarctica and the peninsula. Over the last few hundred years, it appears the Antarctic peninsula's temperature seems to vary inversely with the temperature of inland Antarctica. When the inland is very cold, the Antarctic peninsula is warm and vice versa. Mosley-Thompson and her team are interested in whether or not that correlation holds up over many, many years.
In the best case scenario, Mosley-Thompson's team will be able to spot individual years in the "laminated" layers of ice and snow going hundreds of years back and less high-resolution data going back multiple thousands of years. At the top of the core, it's easy: Individual years can be more than a foot and a half thick. At the bottom, years can be compressed into fractions of an inch, making it impossible to tell them apart, even if they still have scientific value. To preserve the ice cores, it's imperative that they, well, don't melt.
As you might imagine, the infrastructure required for the operation is tremendously complicated. The National Science Foundation cut a deal with the large government services company Raytheon for long-term logistics. Raytheon Polar Services employs 350 full-time employees and hires more than 1,000 contractors to staff the various transportation and residence facilities. The NSF recently extended the Raytheon contract by a year.
Raytheon Polar Services controls the transportation of both scientists and scientific equipment around what they call "The Ice" and back home. In Mosley-Thompson's case, they were aided by the British Antarctic Survey.
Their expedition launched from the British Rothera Research Station on Adelaide Island. Bad weather kept them from venturing to their field location on the Bruce Plateau for ten days, so when they did make their move they had to be quick. Four Twin Otter aircraft carried the crew and their equipment to the remote location, getting everything into position in just five hours.
Once on the ground, they had to set up their working dome and sleeping tents. You can see the geodesic dome being constructed in the video at the top of the page. They spent 42 days working within its confines.
As they drilled the 1,500 feet (445 meters) to the bedrock, they pulled up chunks of the ice, which were carefully catalogued and cut into 3.3 foot (one meter) chunks. Insulated core boxes can hold six of the chunks. Then, they were buried in a trench in the snow to keep them cold. When the weather permitted, The Twin Otters stopped by to pick up about 15 core boxes at a time.
As the cores arrived back at Rothera, they were placed in two huge refrigerators. Finally, on Sunday, the Nathaniel B. Palmer icebreaker research vessel headed to the station. The freezers were lifted whole onto the boat. They'll chug along to Punta Arenas in Chile, where they'll be loaded onto a regular cargo ship for the last leg of the sea trip.
At Port Hueneme, they'll be loaded onto refrigerated semi-trucks, just like the ones that deliver frozen peas to your local Safeway. And it's those vehicles that will finally deliver the cores to Columbus. Many other ice cores go through the National Ice Core Laboratory in suburban Denver, Colorado.
If the logistical high-wire act fails, the data is just gone. "Nobody will fund you to go again," Mosley-Thompson said. With her cores now on the boat headed north, she said that she talks with her contact at Raytheon multiple times a day to ensure that everything is going smoothly.
Images: Ellen Mosley-Thompson.
Posted: 13 Apr 2010 02:06 PM PDT
A bevy of backward-orbiting exoplanets could challenge theories of planet formation, new research suggests. The planets' wonky orbits might also rule out the presence of Earthlike bodies in some planetary systems.
The wrong-way planets got where they are by cartwheeling over their stars' heads, Andrew Collier Cameron of the University of St Andrews in Scotland proposed in an April 13 presentation at the Royal Astronomical Society's National Astronomy Meeting in Glasgow, Scotland.
Planets are thought to form from the disk of gas and dust that surrounds a young star. Because the star and the disk both coalesce from the same cloud of material, theory holds that both should spin in the same direction — and so should any planets that arise. The "disk migration theory" posits that some planets should end up close to their stars by gently migrating inward over time, maintaining an orbital plane in line with the star's rotation.
Last summer, astronomers first discovered a handful of planets that threw that idea for a loop. These planets orbit backward, opposite to the direction of their stars' spin (SN: 9/12/09, p. 12). And other newly discovered planets that did have "forward" orbits were tilted 20 degrees or more with respect to the plane of the stellar disk where they were born.
These planets belong to a class of extrasolar planets called hot Jupiters — giants that sit scorchingly close to their stars.
"If I had to stick my neck out and make a prediction, it's probably not a good idea to go looking for terrestrial planets in systems that have hot Jupiters in them," Cameron says.
Cameron and his colleagues think a single mechanism pushed the tilted and backwards planets into their offbeat orbits and also drew them close to their stars. If these slanted orbits are common, it could be a death knell for the migration theory, says study coauthor Didier Queloz of the Geneva Observatory.
"Migration cannot produce misaligned systems," Queloz says. The new study brings the total number of planets for which astronomers have angle data up to 27. Of those many are misaligned, with half tilted at steep angles and six orbiting backwards.
"Since most hot Jupiters are indeed misaligned, most cannot be formed by migrations," Queloz says. "We're kind of killing this first idea of migration."
The more likely explanation, the researchers say, is the Kozai mechanism. In this scenario, a second, distant large body like a planet or a companion star gravitationally perturbs a planet's orbit. The orbital plane can flip over the top of the star like a jump rope. When the orbit is flipped more than 90 degrees, the planet is orbiting backwards. At the same time, the shape of the orbit squishes and stretches like a rubber band. As the planet gets closer to the star, its orbit gets more circular, and the cartwheels become less dramatic. When the orbit finally settles into a circle near the star the tilt freezes.
Earlier research predicted that most orbits of giant planets perturbed by the Kozai mechanism should end up tilted around either 40 degrees — a forward but slanted orbit — or 140 degrees — a backwards orbit.
"That looks very much like what we're now observing," Cameron says. "It looks almost too good to be true."
Some critics think he's right — it is too good to be true. "I think they're eliminating the standard mechanism of disk migration prematurely," says Adam Burrows of Princeton University. Some combination of migration, scatter and the Kozai mechanism is still possible, he says. "Their data isn't that definitive to eliminate any other possibilities."
Astronomers had hoped that smaller, more Earthlike planets could be hiding in the neighborhoods of hot Jupiters, but the recent slug of orbital data suggests that may be unlikely. The giant planets' orbits can take hundreds of thousands of years to settle, "during which you have a rampaging Jupiter on a cometlike crazy tumbling orbit, which would simply fling any remaining debris out of the system," Cameron says.
Images: 1.ESO/L. Calçada2.ESO/A. C. Cameron
Posted: 13 Apr 2010 01:06 PM PDT
Genetic tests of whale meat from Japanese restaurants in Los Angeles and Seoul, South Korea, have confirmed the meat is from endangered animals.
The Los Angeles bust was publicized in March, prompting a restaurant there to close, but finding the meat in South Korea was even more troubling.
"This problem may be more widespread than we originally thought," said Scott Baker, a whale researcher at Oregon State University. The identifications are described in a paper published April 13 in Biology Letters.
Killing sei, fin and minke whales was outlawed by the International Whaling Commission in 1986, and trade in their products is forbidden by the Convention on International Trade in Endangered Species.
Possessing or selling whale meat is illegal in the United States. Japan and South Korea allow endangered whales caught as "bycatch" by fishermen to be sold. Japan also operates a research program that's been criticized as scientific cover for continued whale hunts.
Sei whale meat from The Hump in Los Angeles, purchased last October by makers of the The Cove — a documentary about Japanese dolphin hunting — proved genetically similar to meat purchased at markets in Japan during 2007 and 2008. It likely came from the same whale population. The restaurant has since closed.
Of sei, minke and fin whale meat purchased last year by the paper's authors in an as-yet-unidentified South Korean restaurant, the fin whale matched with meat sold in Japan in 2007. It likely came from the same individual.
Baker's team has asked the Japanese government for access to its DNA registry of research whales. If granted, it could confirm the meat's origin in the Japanese research program. It could also implicate an unknown source, "a situation requiring urgent investigation," write the researchers.
Images: Oregon State University/Flickr: 1) From a restaurant in Seoul, a sashimi plate containing cuts from four whale and one dolphin species; 2) A waiter serves whale at The Hump restaurant in Los Angeles.
Citation: "Genetic evidence of illegal trade in protected whales links Japan with the U.S. and South Korea." By Charles Baker, Debbie Steel, Yeyong Choi, Hang Lee, Kyung Kim, Yong Ma, Charles Hambleton, Louie Psihoyos and Robert Brownell Jr.. Biology Letters, April 13, 2010.
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