Biosignatures of Fe-oxidizing microbes

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: 

  1. What criteria can we use to distinguish biotic from abiotic Fe mineral precipitates?
  2. What environmental conditions do FeOM biosignatures indicate? 
  3. 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

Project Team

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.

Featured Faculty

Clara Chan

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Associate Professor Geological Sciences


CEOE School & Departments

School of Marine Science & Policy

Advancing the understanding, stewardship, and conservation of estuarine, coastal, and ocean environments.

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Department of Geological Sciences

Discovering how geological processes have operated over various time scales to create and influence the planet’s surface environments.

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Department of Geography

Investigating the interactions between people and the environment and the processes that explain the location of human and natural phenomena.

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