Optical Imaging Reveals Link Between Bacteria and Rock Formation

Researchers are using laser imaging techniques to study the interaction of bacteria with calcium carbonate (CaCO₃), a common chemical compound found in rocks and shells throughout the world.

This work is important because it provides details on how carbonate rocks (such as limestone, marble, and chalk) form and dissolve. As the single largest reservoir of inorganic carbon on earth, carbonate rocks contain approximately 65 million gigatons of carbon. When these rocks form or erode, large amounts of carbon dioxide may be released, which would affect the global climate.

The researchers developed high-resolution laser microscopy and imaging techniques to study the bacterially induced mineralization process. When combined with fluorescent stains and imaging agents, the techniques produce 2-D and 3-D images that the researchers analyze to determine the amount of CaCO₃ present, cell numbers and components of the surrounding support system.

Imaging allows for non-destructive observation of bacterial activity and mineral growth. The investigations will help close the gap that exists between static laboratory methods used to understand biogeochemical processes and naturally occurring dynamic systems.