Some Deep-Sea Microbes Are Hungry For Rocket Fuel
It's life, but not as we know it. Researchers in the Netherlands have found that a microbe from deep beneath the ocean can breathe a major ingredient in rocket fuel. The discovery suggests that early life may have used many different kinds of chemicals besides oxygen to survive and thrive.
Some of the harshest conditions on Earth lie inside hydrothermal vents. These vents are hot spots generated by volcanic activity on the ocean floor, and they're not anywhere you'd want to go swimming. In addition to being unbearably warm, they're under enormous pressure, and often the surrounding water lacks dissolved oxygen.
The creatures living in these vents are mostly single-celled organisms. "When you do see them in the microscope they don't always look very spectacular," says Rick Colwell a geomicrobiologist at Oregon State University. But don't let their modest appearance fool you: These microbes are unlike almost anything on Earth. They're bacterialike creatures called Archaea, and they can survive without oxygen.
Colwell and others think that these Archaea cells may resemble the earliest forms of life. Billions of years ago, before algae and plants were around, there was no oxygen on the planet. Archaea-like organisms may have ruled supreme.
Among the most commonly seen and studied Archaea is a bug called Archaeoglobus fulgidus. It lives in ocean vents and hot springs all over the planet, using sulfur-based chemicals instead of oxygen to breathe.
Martin Liebensteiner, a graduate student at the University of Wageningen in the Netherlands, decided to put something else in A. fulgidus's atmosphere: rocket fuel.
Liebensteiner was interested in a chemical called perchlorate. It's a major ingredient in solid-rocket motors like those used on the space shuttle. It also exists naturally in small quantities on Earth, and on Mars. Some bacteria can use perchlorate to survive, and Liebensteiner wanted to see if the Archaea might also be able to use it as an oxygen substitute.
It's not part of A. fulgidus's normal diet, but the little guys seem to love it. "We found out it's using it for growth and for survival," he says. The work appears in Thursday's issue of the journal Science.
Liebensteiner says the new work shows that the ability to breathe many different chemicals might be more fundamental to early life than previously thought. Colwell agrees. A. fulgidus' ancestors probably sucked up whatever chemicals they could to survive on the hostile early Earth.
"They develop a sort of diversity, a bag of tricks if you will, that allow them to survive under different conditions, and this might be one," he says.
In other words, these microbes may have been feeding on rocket fuel for billions of years before humans discovered it. But don't feel too inferior. We're still the ones that invented the rockets.
ROBERT SIEGEL, HOST:
Now to a scientific finding about a tiny microbe with a strange diet. Researchers in the Netherlands have found that an organism living deep in the ocean can survive on rocket fuel.
As NPR's Geoff Brumfiel reports, the creature's diet might tell us more about the earliest life on the planet.
GEOFF BRUMFIEL, BYLINE: There are spots on the ocean floor where volcanic activity causes the water to boil.
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BRUMFIEL: These places are called hydrothermal vents. They're hot, the pressure's high, and there's no oxygen dissolved in the water.
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BRUMFIEL: I have to say it doesn't sound like the greatest place to go swimming.
RICK COLWELL: It's probably not. But for these organisms it's their spot.
BRUMFIEL: Rick Colwell is a geomicrobiologist at Oregon State University. He studies the microbes that live in the vents.
COLWELL: When you do see them in the microscope, they don't always look very spectacular. Some of them do, but most of them look kind of simple - little round cells that are quite small.
BRUMFIEL: These little round cells may resemble the earliest forms of life on Earth. In the beginning, there was no oxygen. Unlike almost all animals living today, these microbes don't need it. Figuring out what they do need may provide clues about life's beginnings.
Martin Liebensteiner is graduate student in the Netherlands.
MARTIN LIEBENSTEINER: I'm working at the University of Wageningen.
BRUMFIEL: He's studying a particular kind of bug that thrives in the boiling vents, Archaeoglobus fulgidus.
LIEBENSTEINER: It's a kind of bacteria-like cell.
BRUMFIEL: Liebensteiner took some Archaeoglobus, put it in a beaker and fed it. And this is where it gets a little wild.
UNIDENTIFIED MAN: Three, two, one, zero and lift-off.
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BRUMFIEL: The space shuttle's boosters used fuel containing a chemical called perchlorate. Liebensteiner gave his microbes a perchlorate-only diet. This was something new to them. In the vents they use other chemicals for energy. But as Liebensteiner writes in a paper in Science, the little guys seemed to love their rocket-fueled menu.
LIEBENSTEINER: We found out, it's using it for growth and for survival.
BRUMFIEL: The fact these microbes could use perchlorate on the fly isn't as strange as it first seems, says Rick Colwell.
COLWELL: Yeah, it does seem weird. But the chemical does exist naturally in various places on our planet and also on Mars, for instance. And so, microorganisms who've been around for quite awhile have seen this material and have recognized it as a compound that they could use.
BRUMFIEL: The study suggests that this bug's ancestors sucked up whatever chemicals they could to survive.
COLWELL: They develop a sort of diversity; a bag of tricks that they have, if you will, that allow them to survive under different conditions and this might be one.
BRUMFIEL: In other words, these bacteria may have been using rocket fuel, billions of years before humans did. But don't feel too inferior. We're still the ones that invented the rockets.
Geoff Brumfiel, NPR News
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