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Clara Chan

Associate Professor


I study geomicrobiology, in particular the interactions between microbes and minerals. My research focuses on microbial mineralization, including characterizing mineral phase, morphology, and reactivity, as well as investigating the roles microbes play in precipitation and crystallization processes. I take a multidisciplinary approach, combining geochemical field characterization and sampling, molecular biology, biochemistry, culturing and a wide variety of microscopy and spectroscopy techniques.

Department Affiliation

Department of Geological Sciences 

Current Projects

Biosignatures of Fe-Oxidizing Microbes - Microbial Fe oxidation occurs in low oxygen, Fe-rich redox gradient environments, where abiotic oxidation rates are slow. We hypothesize that Fe-oxidizing microbes (FeOM) play important roles in these gradient environments where they fix carbon and precipitate reactive Fe minerals. Read More

Microbe-S(0) interactions - We are working with a model S-oxidizing phototroph,Chlorobaculum tepidum, in collaboration with Tom Hanson, funded by the UDRF Strategic initiatives program and NSF. Read More 


B.S., Geological and Environmental Sciences, Stanford University, 1997
M.S., Civil and Environmental Engineering, Stanford University, 1998
Ph.D., Earth and Planetary Science, University of California, Berkeley, 2006

Selected Publications

Kato, S., Ohkuma, M., Powell, D. H., Krepski, S. T., Oshima, K., Hattori, M., Shapiro, N., Woyke, T., and Chan, C. S. (2015) Comparative genomic insights into ecophysiology of neutrophilic, microaerophilic iron oxidizing bacteria, Frontiers in Microbiology, doi: 10.3389/fmicb.2015.01265.

Hanson, T. E., Bonsu, E., Tuerk, A., Marnocha, C. L., and Chan, C.S. (2015) Chlorobaculum tepidum growth on biogenic S(0) as the sole photosynthetic electron donor, Env. Microbiol., doi: 10.1111/1462-2920.12995.

McAllister, S. M., Barnett, J. M., Heiss, J. W., Findlay, A. J., MacDonald, D. J., Dow, C. L., Luther, III, G. W., Michael, H. A., and Chan, C. S. (2015) Dynamic hydrologic and biogeochemical processes drive microbially enhanced iron and sulfur cycling within the intertidal mixing zone of a beach aquifer, Limnol. Oceanogr., 60, 329-345.

MacDonald, D. J., Findlay, A.J., McAllister, S. M., Barnett, J. M., Hredzak-Showalter, P., Krepski, S. T., Cone, S. G., Scott, J., Bennett, S. K., Chan, C. S., Emerson, D., Luther, G. W. (2014) Using in situ voltammetry as a tool to search for iron oxidizing bacteria: from fresh water wetlands to hydrothermal vent sites, Env. Sci. Process. Impact, 16, 2117-2126.

Research Interests

Geomicrobiology, biomineralization, biofilms, biosignatures, nano-and environmental mineralogy, environmental geochemistry.


Biosignatures of Fe-Oxidizing Microbes
TEM image of Mariprofundus ferroxydans stalks

Modern iron-oxidizing microbes and putative microfossils are aiding the identification of biosignatures in the rock record.

Microbe-S(0) interactions

How do microbes make and consume elemental S(0)?

Geomicrobiology (GEOL 467/667-010)

An exploration of the interface between geological and biological processes.

Earth Materials I: Minerals (GEOL 300)

Fall 2010, now changed to: Earth Materials (GEOL 202) Fall 2012, every year.

Writing in Geosciences (GEOL 667)

Approaches to writing in the geosciences.


Morphology of biogenic iron oxides records microbial physiology and environmental conditions.

FEMS Microbial Ecology

Hidden in plain sight: discovery of sheath-forming, Fe-oxidizing Zetaproteobacteria at Loihi Seamount.

Chan Publications

View a full list of publications by Clara S. Chan


• Geochemistry• Geobiology


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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College of Earth, Ocean, and Environment • 111 Robinson Hall • Newark, DE 19716 • USA
Phone: 302-831-2841 • E-mail: ceoe-info@udel.edu

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