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AMASE team members hiking up the Sverrefjell volcano. Credit: Kjell Ove Storvik. |
An international team of scientists has found life on a Norwegian island. No surprises there, but the successful field test of a collection of life-detection instruments may be a stepping stone for future endeavors to sniff out life on Mars.
"It's the first time we have employed a package of tools ranging form spectroscopy to microbial techniques," said the lead investigator, Hans Amundsen of the University of Oslo, Norway.
The Arctic Mars Analogue Svalbard Expedition (AMASE) is a collaboration of geologists, biologists, engineers and even artists, who recently lugged their instruments into the Bockfjorden region on Svalbard, an archipelago about 900 miles above the Arctic Circle. The team chose the site for its geological similarities to Mars.
"This is a reasonable analogue of Mars," said Pamela Conrad of NASA Jet Propulsion Laboratory (JPL) and one of the AMASE members. Although technically an Arctic desert, Conrad thinks that this area of Svalbard may more closely resemble the conditions on the red planet when it had more water.
The long-range goal is to send some version of the AMASE instruments to Mars to look for signs of past or present life. If there are Martian organisms similar to those on Earth, then the AMASE team is confident they could detect them.
"If we had one microbial cell, we would find it," Amundsen said.
Cold coasts and Martian rosettes
The AMASE researchers found many microbes living in the rocks of Svalbard. These "cryptoendolithic" organisms are observed in many places, including the dry valleys of Antarctica. Norman Pace, a biologist at the University of Colorado, Boulder, said that if there is life on Mars, it will likely be cryptoendolithic.
Svalbard hosts more than just microbes, though. A human population of 2,700 is scattered among a handful of Norwegian settlements and a Russian coal-mining community. There are reindeer and polar foxes that dot the glacier-strewn landscape, and the number of polar bears rivals that of people.
The place where the scientists set up camp, however, was a rocky barren place, lacking much of any signs of life.
"It looks like a scenery from Mars," Amundsen said.
Svalbard is the northernmost territory of Europe. The Vikings discovered the islands in 1194 and called them "the land of the cold coasts." The many fjords that define the shoreline are frozen much of the year, leaving only a small window for scientific expeditions.
The AMASE team went to Svalbard for two weeks in mid-August when the summer sun never set. According to Conrad, the 24-hour days invigorated the scientists to stay up late doing research.
The main reason, though, for choosing Svalbard was not the extended work hours, but the fact that the same carbonate globules, or rosettes, in the famous Martian meteorite ALH84001 are also found around the Sverrefjell volcano on Svalbard.
Some scientists claim that ALH84001 contains fossils of microbial life. The evidence centers on mineralogical features that may have a biological origin. Conrad explained that, generally speaking, microbes can make minerals or affect the chemistry out of which minerals form.
The features of ALH84001, however, may have nothing to do with life at all. The issue is hotly debated, and many remain unconvinced.
"If the question is: 'Does [ALH84001] contain evidence for life,' my answer is, 'no,'" Pace said.
Amundsen and Conrad do not think microbes made the Svalbard rosettes. Amundsen speculated that the Sverrefjell volcano erupted about a million years ago, and the rosettes, which are about 100 microns wide, likely formed shortly afterward.
But the fact that Svalbard produced carbonates, which the AMASE team says are the most similar on Earth to the carbonates in ALH84001, may mean there was a Svalbard-like setting at one time on Mars.
"We wanted to look at the geologic 'crime scene', so to speak," Amundsen said.
Determining which features of the Svalbard geology are - and are not - due to biology will help provide some context for ALH84001, no matter what the final word is on this meteorite.
Crime scene investigators
To inspect the geology and biology of Svalbard, the AMASE team brought with them various instruments.
What might be considered the first line of inquiry was the multi-channel deep ultraviolet excitation (McDUVE) fluorescence detector. This spectroscopic device from JPL shines ultraviolet light on a rock or patch of ground and records the lower frequency light (or fluorescence) that shines back.
"The color at which material fluoresces says what molecules are there," Conrad said.
No preparation of the sample is necessary, and the energy used is not enough to harm any living organisms, Conrad explained. The wavelength of the light gives a high sensitivity for discriminating between mineralogical and organic compounds.
"The device is about as big as a shoebox," Conrad said. "In about 50 microseconds, it tells you if there are organic molecules present."
With this quick, non-destructive test, a rover could select potential samples for further testing.
A suite of microbial detectors from the Carnegie Institution provides this sort of follow-up.
One device performs a polymerase chain reaction (PCR) to characterize any DNA that is present. Other instruments detect cell walls and ATP, which is an energy-storing molecule used by cells.
The Carnegie Institution is also developing protein microarrays, which can simultaneously search for hundreds of different molecules. When a dissolved sample is placed on a special slide, targeted molecules will bind to particular spots, causing a blip of light.
"You can get very many answers on a single slide, depending on what questions you put on it," Amundsen said. "It's a problem to pose the right questions."
The microarrays can pinpoint proteins and DNA, as well as amino acids and nucleotides. The expedition to Svalbard was the first time that these microarrays had been used in the field, and the results agreed with the more established detection methods. Both Amundsen and Clark see microarrays as very promising.
Life Not As We Know It
But Jeffrey Bada of the Scripps Institution of Oceanography questions AMASE's use of microbial technologies that have been developed to identify familiar molecules.
"This is not the way you want to look for life elsewhere," Bada said. "It is too Earth-centric."
One problem is that if Earth-like organisms are detected on another planet, it becomes hard to rule out contamination from our own space probes.
"It might be 'us' - we might have brought it," Bada said. The trouble is finding markers that will distinguish the Martians from us.
"Looking for life as we don't know it - that's when you really start to scratch your head," he said.
Common Seeds
Still, it is possible that extra-terrestrial life, if it exists in our solar system, is similar to life on Earth. There has been a certain amount of rock sharing between the planets, evidenced by ALH84001 and other Martian meteorites. Perhaps, biological material hitched a ride on a meteorite.
"Wherever life originated from, it has likely been blasted around the solar system," Pace said.
Whether space-traveling organisms could survive the transit is a big question, but it does open the possibility that these meteorites could have seeded nearby planets.
"I believe if we detect life on Mars, it may be genetically related to life on Earth," Pace said.
But Pace thinks that the probability is very low that there is life on Mars. And like Bada, he disagrees with the strategy of AMASE. "It's not the way you hunt," he said of the microbial instruments. He thinks that the first goal should be to find organic molecules, then analyze them for life signatures.
Multiple Flashlights
Clearly, there are different opinions on how to explore Mars and elsewhere. Some in the community see this variety as a virtue, as there is unlikely to be a single "smoking gun" of life in these far-off places.
"You want to have multiple avenues to attack this problem," said Susan Brantley, a geobiologist at Penn State University. She compared it to shining a flashlight on an elephant. "You want as many flashlights as you can get, so you see the whole elephant," she said.
There are other flashlights being developed and tested in places like the Atacama Desert of northern Chile, the Rio Tinto in Spain and Antarctica. Some groups have begun to automate their experiments. The AMASE team is also thinking about how this might be done.
"All these techniques can be improved and miniaturized to go on a rover," Amundsen said. He thought that maybe the number of instruments could be reduced to two.
"We all love space exploration," Conrad said. "Our goal is to get something on Mars."
