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U.S. Forest Service

Serpentinization and Microbial Processes in Alkaline Seeps and Springs of Ultramafic Rocks

What do Darlingtonia wetlands and outer space have in common? A researcher from NASA is interested in finding out. Dr. Dawn Cardace is investigating the ancient subduction areas of the Klamath-Siskiyou Mountains, specifically their serpentine waters, for potential applications for life on other planets.

The premise is that hydrogen, present in water in a free form (no charge and thus distinct from the H+ and OH- ions defining pH), can fuel microbial metabolism in an otherwise energy-limited environments on Earth. Dr. Cardace will be sampling for high pH springs or seeps (pH>10) where fresh reaction fluids are seeping out of the ultramafic bedrock, a rock type akin to those on other planets. If not for the springs or seeps, one would have to engage in deep see drilling or take a trip to Mars to get the kind of information these waters can provide.

Dr. Dawn Cardace collecting water samples in a Darlingtonia wetland. Dr. Dawn Cardace collecting water samples in a Darlingtonia wetland to test pH. Photo courtesy of Dr. Dawn Cardace.

She predicts that through geochemical modeling of the free hydrogen available to microbes that there is enough in the fluids percolating through these rocks to keep microbes alive and multiplying for a long time. Her research will either prove or disprove this hypothesis. If the modeling indicates there is enough free hydrogen available to fuel microbes, it is plausible, given pre-requisite environmental conditions (e.g. water availability), that microbial metabolisms could take place on other planets comprised of rock types similar to those of Earth’s mantle.