[meteorite-list] Expedition Turns Up Life on Pseudo-Mars

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Wed Sep 29 16:49:05 2004
Message-ID: <200409292049.NAA23066_at_zagami.jpl.nasa.gov>

http://www.space.com/businesstechnology/life_detection_040929.html

Expedition Turns Up Life on Pseudo-Mars
By Michael Schirber
space.com
29 September 2004

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."
Received on Wed 29 Sep 2004 04:49:01 PM PDT