Oil-Munching Bacteria Found in La Brea Tar Pits
Jennifer Martin, CSREES Staff (202) 720-8188
August 14, 2007
By Stacy Kish, CSREES Staff
Scientists recently recovered approximately 300 previously unknown species of bacteria from oil-permeated soil, which they estimate to be 28,000-years-old, at the Rancho La Brea Tar Pits in Los Angeles, CA. The bacteria, which use the oil as a food source, could lead to new methods for cleaning oil spills, developing alternative energy and enhancing oil recovery.
The bacteria found in the oil samples work as a community to degrade the heavy oil and produce useful byproducts, like methane, the principle component of natural gas.
David Crowley and his team at the University of California, Riverside uncovered a rich microscopic community that represent new orders and families in the tree of life. Crowley and his team used DNA methods to recover gene sequences from bacteria species, a feat necessary to correctly identify the microorganisms living in this environment.
Scientists believe that the bacteria most likely entered the tarpits through the soil and evolved in a stew of hydrocarbons (oil) rich in mutation-causing toxic chemicals and metals. Survival in this harsh environment required the organisms to rapidly repair DNA exposed to mutation-causing solvent mixtures.
Species diversity in the oil sample was remarkably low compared to a normal soil sample, supporting the idea that the harsh environment selected for specific organism traits that are key to survival. In addition, the organisms developed a way to harness energy from the oil by producing hydrogen sulfide and methane. The scientists also found genes coded for enzymes that function in the breakdown of aromatic chemicals, such as polychlorinated biphenyls (PCB). The latter two findings may help promote alternative ways to clean up oil spills and more effectively use oil products.
The research is presented in the July issue of the journal Applied and Environmental Microbiology.
The USDA's Cooperative State Research, Education, and Extension Service funded this research project through the National Research Initiative (NRI) Soil Processes program. NRI is the largest peer reviewed, competitive grants program in CSREES. It supports research, education and extension grants that address key problems of national, regional and multi-state importance in sustaining all components of agriculture.
CSREES advances knowledge for agriculture, the environment, human health and well-being, and communities by supporting research, education and extension programs in the Land-Grant University System and other partner organizations. For more information, visit http://www.csrees.usda.gov.