Scientists looking for clues to the origins of life on Earth have discovered new life-forms right here in Sonoma County that may shed light on how life evolved -- and how it might be detected elsewhere in the universe.
A three-year study of alkaline ponds at The Cedars, a vast but remote serpentine area north of Cazadero, has uncovered microorganisms never before detected, existing in the kinds of harsh conditions believed to reflect those that first gave rise to life, scientists say.
Researchers hope that studying these unique microbes and how they function may impart information about the biochemical reactions that imbued inorganic substances on early Earth with the spark of life.
"In the next few years, we're going to know a lot about these organisms, and that, I think, will stimulate a lot of thinking in these kinds of areas -- both in the origins of life and in the limits of life," said Kenneth Nealson, a professor with the University of Southern California's Wrigley Institute who participated in the research published last month.
The Cedars' very appearance hints at the insights the area might yield into how primitive or even extraterrestrial life began and functioned in a hostile, anaerobic environment.
Terms like "unearthly," "otherworldly" and "moonscape-like" have been used to describe the dramatic, rugged terrain located off a winding, private dirt road that crosses Austin Creek a half-dozen times and passes through a series of locked gates.
It's easy to imagine the raw, barren scarp that rises a thousand feet above the headwaters to Austin Creek existing somewhere on another planet. A Mars rover would look at home against its reddish hues and crumbling scree.
Below the sheer ridgeline, white-crusted ponds lined with cream-colored silt and "mineral falls" coated with thick, glistening yellow evoke the kind of primordial soup from which the first creatures on Earth might have emerged.
During summer months, the dry, rocky creekbed reveals spring-fed pools encrusted with fragile calcium carbonate structures and terraced formations that contribute to the strangeness of the place.
"You really do feel like you're somewhere different -- you've been transported," said Michael Cohen, an associate professor of biology at Sonoma State University, who is conducting his own studies of microorganisms from springs for potential use in biofuel production.
"I think it's about the most extraordinary place in the county," said Ralph Benson, executive director of the Sonoma Land Trust, which owns a small chunk of it.
What differentiates the isolated region from most of what surrounds it is the massive outcropping of serpentine rock on which it's located, the result of a mineral called peridotite that got jammed up onto the continent at the boundary of moving tectonic plates tens of millions of years ago. Peridotite, a key constituent of the planet's mantle, is more commonly found many miles beneath the Earth's crust.
Peridotite is unstable, producing serpentine when it interacts with water under pressure. This interaction also releases calcium bicarbonate, methane, hydrogen and high pH fluid like that which bubbles up through the rock at The Cedars, accounting for the ultra-
alkaline ponds and calcium carbonate formations.
But these springs otherwise appear to lack essential elements for life as we know it, like oxygen, salt in any real quantity and other electron acceptors that would offer potential for conversion of energy, scientists say.
The spring water has pH levels approaching 12 -- about the same as lye. Though the microorganisms within exist in a density so low it's a fraction of what's commonly found in drinking water, they survive, and do so consistently, despite the odds, Nealson said.
Nealson, who has studied life at the extremes of temperature, described the deep spring at The Cedars as "one of the most challenging environments I've ever seen."
"The essence is that, when you put it all together, there is no life on Earth that should really be living there," he said. "It kind of broadens the places that you might look (for life) in our own solar system, or even outside our own solar system, if we ever get there."
The research team's findings complement ongoing studies at other serpentine areas around the globe, primarily on the seafloor, where the raw materials of early Earth come together.
And they fit well with the prevailing theory of life beginning in highly alkaline waters from the conversion of peridotite produced within the planet.
"This is probably the most accepted idea right now for the origin of life -- that it arose out of an area similar to what you'll find in these springs, except probably in the ocean," said Cohen at SSU.
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