Helping Detect Life on Other Planets, Clean Up Earth

Newswise — Nearly 70 years since H.G. Wells scared the nation with his "War of the Worlds" radio hoax, researchers at the University of Missouri-Rolla are now working on a technique that could show whether life on Mars ever existed. Dr. Estella Atekwana, associate professor of geology and geophysics at the UMR, is studying the relationship between rocks on Earth and the tiny organisms surrounding them, and how the microbes can clean up contaminated areas. She says a technique being developed to help monitor the cleanup of contaminants on Earth could be used to determine the existence of life or evidence of previous life on other planets. "The results of our work may have significant implications for exploring for life on other planets," says Atekwana. "Understanding the geophysical response of biosignatures or biological activity in geologic media may help toward the development of appropriate geophysical instrumentation for exploring the surface of other planets for life." In a recent research paper, titled "Relationship Between Biodegradation and Bulk Electrical Conductivity," Atekwana looks at how certain microbes interact with minerals and how this interaction affects the subsurface environment. Based on this research, she hopes to develop a hands-off technique to monitor bioremediation in contaminated areas on Earth before venturing to other realms of the universe. Although Atekwana has worked in biogeophysics for more than six years, she says it is a relatively new area in geology and geophysics. "It is very cross-disciplinary and has required that I work with biologists and geochemists to better understand how microbial interactions with geologic media translates to a change in the physical properties of the subsurface media and the resulting geophysical response," says Atekwana. Biogeophysics uses geophysics to investigate biological processes. Atekwana is currently studying how toxins such as hydrocarbons, gasoline, diesel and kerosene can be remediated using microorganisms. The microorganisms use the carbon source from toxins for energy which produces water, carbon dioxide and organic acids as byproducts. The carbon dioxide dissolves in the water to form carbonic acid, which together with the organic acid speeds up the weathering and dissolution of the minerals in the rocks, says Atekwana. "It is this process that releases ions from the mineral into the water surrounding the rocks, increasing its ability to conduct electricity," she says. When higher microbial activity is found in areas where an abundant food source such as carbon exists, it shows up in the geophysical data as areas of enhanced conductivity. This is due to the mineral weathering from the acids produced by the microbials. Geophysics can be used to at least indirectly detect the level of microbial activity in rocks, says Atekwana. Using geophysics to monitor the progress of microbial breakdown of contaminants is cheaper than anything used currently and can cover large areas over a short amount of time. "We don't need to dig any holes and contaminated sites can be investigated non-invasively, limiting exposure and risk to engineers working at these sites to contaminants," says Atekwana. Atekwana received her third Best Paper Award for this research from the Environmental and Engineering Geophysical Society at the 16th annual symposium on the Application of Geophysics to Environmental and Engineering Problems in February. Co-authors of the paper include Dr. Eliot Atekwana, assistant professor of geology and geophysics at UMR, and researchers at Western Michigan University.