Metallic ion binding by Bacillus subtilis: Implications for the fossilization of microorganisms

Abstract

The silicification of bacterial cells has been followed in a laboratory simulation by electron microscopy and energy-dispersive X-ray spectroscopy. Structural degradation of the bacteria was not influenced by silica availability, but the remains of degraded cells did promote the precipitation of silica. In contrast, cells reacted with ferric iron before aging remained intact, and structures conforming to the original morphology of the bacteria were preserved by silicification. The binding of metallic ions by microbial cells, in particular the retention of iron, is therefore considered to be an important contributing factor to the fossilization of microorganisms.