jueves, 29 de septiembre de 2011

Rare Arctic Yellow Snow May Yield Clues to Jupiter's Europa

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The patch of yellow snow on a glacier at Ellesmere Island's Borup Fiord Pass has become a key target for researchers led by researcher Damhnait Gleeson of NASA's California-based Jet Propulsion Laboratory. The sulphur-loving microbes of Ellesmere Island could be key to developing telltale "biosignatures" for life relevant to future exploration of Jupiter's ice-shrouded Europa and Mars.

In a new study published in the journal Geobiology, scientists report that they've isolated the species of bacteria — marinobacter — that appears to be causing the stain by "biomineralizing" sulphur bubbling up from a spring somewhere below the ice.

Steve Grasby, a Geological Survey of Canada researcher who is also an adjunct professor at the University of Calgary, said the team's sharpened understanding of the biochemical mechanisms involved in creating the yellow stain on Canada's northernmost major island will ultimately help space scientists construct better diagnostic equipment to test for life on Europa during a future probe to Jupiter.

The Borup Fiord Pass site is "the best analogue we have for what could be going on on Europa," Grasby told Postmedia News on Monday. "All of this can help design a better mission."

Gleeson said Monday that, "the more we can learn about detecting viable biosignatures under a range of extreme conditions, the better prepared we will be to design new life-detection missions."

NASA has previously described the Canadian Arctic's sulphur oddity as a scientific wonder "like none other on Earth."

But Grasby said he recently discovered another icebound spring — just five kilometres from the Borup Fiord location — that also exhibits a sulphur streak. He has taken samples for future study, adding that he's "excited about having a second site." NASA, he said, still has it right in recognizing the "uniqueness" of Ellesmere Island's yellow stains: "There's nothing like it anywhere else in the world."

Last year, a Canada-U.S. research team discovered that the Borup Fiord spring can be pinpointed by infrared sensors housed in an orbiting spacecraft.

Detailed in the journal Remote Sensing of Environment, the 2010 study showed how the Hyperion "hyperspectral" sensor aboard NASA's EO-1 Earth Observing satellite was able to filter images to isolate the unusual chemical activity happening at Borup Fiord's sulphur spring.

Located 600 million kilometres from Earth and smaller than our own moon, Europa has been described by NASA as being "near the top of the short list of places in our solar system that might harbour extraterrestrial life."

Scientists believe the distant moon is covered in ice that "might conceal an ocean of liquid water," a prime prerequisite for life.

In another study published last year, a team of Canadian scientists announced they had discovered "unique," methane-eating microbes living in a cold, salty spring on Nunavut's Axel Heiberg Island, off the southwest coast of Ellesmere.

That find at Lost Hammer Spring was hailed as proof that similar organisms could have survived in such inhospitable conditions on ancient Mars — and could even be living there today.

Source: The Daily Galaxy 

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