Fe-oxidizing microorganisms (FeOM) have likely been oxidizing, or “rusting” the Earth for billions of years, since the times of ferruginous oceans and pyrite sediments. Certain modern FeOM produce distinctive filamentous biominerals that could be promising biosignatures. In order to confidently identify and interpret FeOM biosignatures in the rock record, we are working with modern FeOM and putative microfossils to answer the following questions:
What criteria can we use to distinguish biotic from abiotic Fe mineral precipitates?
What environmental conditions do FeOM biosignatures indicate?
When do microaerophilic Fe-oxidizing microbes first appear in the fossil record?
This is a collaboration with George Luther and David Emerson, as part of the NASA Exobiology program. Read more about the project in this abstract.
Clara Chan, George Luther
Sean Krepski (UD), David Emerson (Bigelow Laboratory for Ocean Sciences)
Relevant publications/products related to project
Krepski, S. T., Emerson, D., Hredzak-Showalter, P. L., Luther, G. W. and Chan, C. S.* (2013) Morphology of biogenic iron oxides records microbial physiology and environmental conditions: toward interpreting iron microfossils. Geobiology, 11: 457-471.
Chan, C. S.*, Fakra, S. C., Emerson, D., Fleming, E. J., and Edwards, K. J. (2011) Lithotrophic iron-oxidizing bacteria produce organic stalks to control iron mineral growth: Implications for biosignature formation. ISME Journal, 5: 717-727.