INSIDE IOWA STATE|
January 26, 2001
Research shows life may have existed on Mars
by Teddi Barron
An Iowa State professor is part
of a research team that has
found compelling evidence that Mars once supported primitive
The researchers discovered evidence of bacteria in a Martian meteorite. Tiny
magnetite crystals -- so-called magnetofossils -- embedded in the meteorite
were confirmed to be the type produced only by a biological process unique
to magnetotactic bacteria.
Dennis Bazylinski, microbiology, was one of nine researchers conducting the
four-year investigation, funded by NASA's Astrobiology Institute. A report
of their research is in the December 2000 issue of the scientific journal,
Geochimica et Cosmochimica Acta.
Bazylinski leads one of the few labs capable of culturing these
magnet-producing bacteria, which are common in many Earth freshwater and
The researchers studied the magnetite crystals that were located in
carbonates in the Martian meteorite. The 4.5 billion year-old meteorite was
found in Antarctica in 1984. Earlier research confirmed that the carbonates
formed on Mars, signaling that the magnetite crystals also were formed on
Magnetite crystals produced by magnetotactic bacteria are chemically pure,
generally defect-free and have a distinctive size and shape. Their
properties are so unusual that they have only been seen in magnetite
crystals produced through biological processes.
"There is currently no known chemical means of producing these magnetite
crystals with their unique morphologies," Bazylinski said. "The significance
to astrobiology and geobiology is that many scientists have been searching
for 'biomarkers' for life, that is, chemical, isotopic or mineral
indications that life was present, either in extreme habitats or in ancient
materials on Earth and, of course, now in extraterrestrial materials. The
need for biomarkers is obvious and these magnetite crystals might prove to
be an excellent biomarker."
Since the team began the research in 1996, observations from the
space-launched Mars Global Surveyor have indicated that Mars had a strong
magnetic field at about the time the carbonate containing the unique
magnetites was formed.
"Now we are trying to answer the question of whether magnetotactic bacteria
could have actually lived
on Mars," Bazylinski said. "And we have found certain aspects of their
metabolism that suggest they might have been able to do so."
The journal Sciencerecently published research showing evidence of
widespread sediment layers on Mars, which the researchers interpret to be
the product of many lakes. Because these lakes may have provided a habitat
for magnetotactic bacteria, this finding supports the possibility that the
bacteria may have existed on Mars, Bazylinski
Dennis Bazylinski is part of a research team that found life may have
existed on Mars. Photo by Bob Elbert.|