By Sid Perkins
Scientists have found microorganisms within Kentucky shale that are eating the ancient carbon locked within the rock. This previously unrecognized dietary habit could have a prevalent role in the weathering and erosion of similar sedimentary rock at many other locations, say the researchers.
The as-yet-unidentified microbes are munching on kerogen, a mixture of large organic molecules formed from the remains of bacteria and algae that were incorporated into ocean-floor sediments millions of years ago. More than 95 percent of the organic matter in carbon-containing sediments is kerogen, which doesn’t dissolve out of the rocks and decomposes very slowly, says Steven T. Petsch, a geochemist at Woods Hole Oceanographic Institution in Woods Hole, Mass.