Bacteria Generate Hydrocarbon Reservoirs
Ethane and propane have been detected in ocean depths near the Galapagos, reported EurekAlert. These heavy energy-rich hydrocarbons may be widespread in ocean sediments. The authors of a paper in PNAS1 believe it is formed by bacteria metabolizing acetate from organic material in the sediment, and that this “upsets the general belief that hydrocarbons larger than methane derive only from thermal degradation of fossil organic material.” Though the paper discusses only the C2 and C3 hydrocarbons ethane and propane specifically, this surprise announcement includes the possibility that heavier hydrocarbons could be formed by processes not yet understood. The end of the paper says cryptically, “Specifically, they signal the presence of an additional process, probably significant in many environments, for extending the terminal degradation of organic material.”
1Hinrichs et al., “Biological formation of ethane and propane in the deep marine subsurface,” Proceedings of the National Academy of Sciences USA, published online before print September 21, 2006, 10.1073/pnas.0606535103.
Maybe lowly bacteria, not decaying dinosaurs, will keep our automobiles (or barbecues) running for the foreseeable future. This announcement could have ripple effects on astrobiology as well as geopolitics. It also illustrates how little we still know about some of the most basic processes on our own planet occurring today. Remain doubtful, therefore, about what some scientists claim was going on billions of years ago.