OF THE MIND
TECH INSTRUMENT CENTER
TO BLACK MOUNTAIN
MAY UNLOCK MAD COW DISEASE
SPEECH WASN'T FREE
September 1996 found Nancy Hinman in Washington, D.C., testifying before the U.S. Senate Subcommittee on Science, Technology and Space. A controversial meteorite from Mars dubbed ALH84001 had been found in Antarctic ice, and scientists trumpeted that it contained fossils of primitive bacteria-like creatures — proving once and for all that life exists beyond Earth.
not so fast. Hinman, a UM geochemist and NASA-funded expert on the
remains of ancient microorganisms, was part of a group asked to give
a second opinion about the Mars rock. She testified the alleged remains
might have been
In fact, she says, ALH84001 had been studied with more scrutiny than any Earth rock. "It was really good for science, actually, because it stirred quite a controversy. It made people go back and look at what they thought were biological signatures right here on Earth."
NASA now has two unmanned rovers — Spirit and Opportunity — trekking across the Martian dunes taking untold thousands of images of sand, craters and rocks. But would researchers recognize primitive Mars life if it stared them in the face? Has the definitive picture proving Martian life already been snapped and nobody noticed?
That's where Hinman and her research partners come in. They study life that has adapted to some of the most extreme conditions on Earth — such as the hot pools of Yellowstone National Park. Scientists suspect that if life exists elsewhere in our solar system — on frigid Mars for example — it may cluster around similar hot vents.
"We need to study these organisms here, so we can recognize them if we find them out there," Hinman says.
Think nothing lives in boiling water? Think again. Microscopic critters called thermophiles have adapted to living in warm water (even your home water heater), and boiling hot pools are home to hyperthermophiles. Over time these things can mold rock, leaving a fossil record, and many live on heat and chemicals the way most creatures need light and oxygen.
"Some eat rock or things like sulfur and iron that come right out of the vents," Hinman says.
Researchers debate whether life on Earth started in hot pools or migrated there from other areas. Hinman suspects these pools were the first cauldrons of life because thermophiles could survive on early Earth — a hot, gassy place that lacked oxygen. And if thermophiles got life going here, maybe they did the same on Mars, which researchers suspect was much warmer in its infancy.
Hinman has been funded by NASA since 1991, and recently she and four female colleagues from neighboring universities landed two grants worth $1.7 million to study the strange realm of thermophiles and similar tough creatures. The grants came from NASA's Exobiology program, which searches for other life in the solar system, other planetary systems that might support life, the origins of life here on Earth and the precursors of life — the building blocks needed to get living things going.
With their first grant, the scientists will delve into how organisms are preserved in hot spring deposits. Hinman says they will study organisms living in the hottest pools in Yellowstone and around the globe. A trip to study the hot pools of Kamchatka, on the remote eastern edge of Russia, already is planned.
With the second grant, they will study any mineral surface that might be populated by microorganisms, not just those associated with hot pools. One example is desert varnish, in which one side of a rock might appear to be a darker color because of weathering, but the "varnished" discoloration actually is caused by a colony of microorganisms. Hinman says many Earth rocks, even those billions of years old, have been altered by microbes.
"So we are looking at mineral surfaces and how microorganisms populate those surfaces and what signatures they leave behind after they are dead and gone," she says.
When her group visits geothermal areas in Kamchatka, Hinman's job will be to characterize the chemical environment of the hot pools. She is particularly interested in comparing the pools of Yellowstone and Kamchatka because of the differences in chemistry. The parent rock in Yellowstone is formed from continental crust, and Kamchatka has more marine sediment.
"I really study the chemistry and form of the deposits in hot springs," Hinman says. "And I work with microbiologists, chemists and geologists to put together the whole picture of what’s happening in these solutions, what are the consequences to the microorganisms and what are the consequences to the rocks that form from them."
Hinman and her team will identify the creatures living in Kamchatka's hot pools, but they also will identify what role the microorganisms play in their geothermal ecosystem — whether they survive on sunlight, organic matter or chemicals.
No cutting-edge research project would be complete without new instrumentation. Hinman says they are field testing a new mobile biofilm unit. A biofilm is a community of organisms that populates a surface. They grow all around us, coating everything from human teeth to hot pool surfaces. The unit, which fits on a truck, can grow biofilms inside itself. So the researchers will be able to sample a Kamchatkan hot pool and whisk the resulting biofilms home with them.
Another new instrument is a laser they will use to blast rock surfaces to see what sort of minerals and elements come off them. Hinman says the immobile laser fits inside two rooms and is located in Idaho Falls, Idaho. The whole blasting process is called laser desorption mass spectrometry.
Hinman admits her fascination for geothermal hot springs is boundless, and she even served as Yellowstone National Park's geothermal geologist during 2000-01 while on leave from UM. She says hot pools are an alien environment that may offer a glimpse of what life was like on primordial Earth.
"For instance, it's likely the earliest organisms on Earth could not tolerate the presence of even small amounts of oxygen," she says.
Oxygen that invades hot pools in the form of chemicals such as hydrogen peroxide and superoxide can cause all sorts of problems. Hinman says this reactive oxygen can cause death or DNA damage to hot pool creatures, much like free radicals that get loose in the human body and cause cancer.
But why study all this? Hinman says research from Yellowstone's hot pools already has yielded the breakthrough of DNA fingerprinting. Also, since some thermophiles can eat rock, maybe some can be found to degrade hydrocarbons, leading to better ways to clean oil spills. Or if some of these organisms can fight buildup of free radicals, maybe they could help fight cancer in humans.
"People have to know that we are more than just curious about where we came from or life on other planets," Hinman says. "There are a lot of applications we can envision, but we don’t always know where the science will lead us."
Ongoing research can yield fresh results. In fact, Hinman says recent studies have made the case for life signs in ALH84001, the Mars rock, even more compelling.
"The rock contains magnetite, a mineral found in the brains of whales," she says. "Birds have it; insects have it. It's a microbially produced mineral that grows in biological systems. It helps these animals navigate, to orient themselves."
Some bacteria also produce this magnetite, but they only produce magnetite that has a particular shape and orientation, which happens to be the same type of the mineral found in the Mars rock. Hinman says researchers have not been able to duplicate that particular shape and orientation without life getting involved.
"This is one piece of evidence that continues to support the hypothesis that Mars fossils really are in the rock," she says.
So would Hinman rather be going to Mars for her research than Kamchatka?
"I always say I don't have enough frequent flyer miles to get to Mars yet," she laughs, "but I'm working on it."