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Colleen Hansel
- Assistant Professor of Environmental Microbiology on the Gordon McKay Endowment
Contact Information
| Office: | Pierce Hall 118 |
| Email: | hansel [ AT ] seas [ DOT ] harvard [ DOT ] edu |
| Office Phone: | (617) 495-2858 |
| Office Fax: | (617) 496-1471 |
| Lab Name: | Microbial Geochemistry |
| Lab Room: | Engineering Sciences Lab 305 |
| Lab Phone: | (617) 495-5793 |
| Assistant: | Norma J. Stewart, , C.H.A. |
| Office: | Pierce Hall 126 |
| Email: | nstewart [ AT ] seas [ DOT ] harvard [ DOT ] edu |
| Office Phone: | (617) 495-0627 |
| Office Fax: | (617) 496-1471 |
| Lab Room: | Engineering Sciences Lab 3rd floor |
| Lab Phone: | (617) 495-0627 |
Education
- B.S., 1997, Geology, California State University-Sacramento
- M.S., 1999, Soil Chemistry, University of Idaho
- Ph.D., 2004, Soil and Environmental Biogeochemistry, Stanford University
Research Areas
- Environmental Sciences and Engineering: Environmental Chemistry
- Environmental Sciences and Engineering: Environmental Microbiology
Research Profile
Colleen Hansel earned her Ph.D. (2004) from Stanford University in Soil and Environmental Biogeochemistry. She earned her M.S. (1999) from the University of Idaho in Soil Chemistry and her B.S. (1997) from California State University-Sacramento in Geology.
Prior to coming to Harvard, she served as a postdoctoral scientist at Stanford University in Molecular and Microbial Ecology.
Hansel is a member of the American Geophysical Union; the Geochemical Society; the American Society of Microbiologists; and the Mineralogical Society of America.
The Hansel lab investigates the mechanisms underpinning microbially-mediated metal redox transformations and mineralization using both a geochemical approach to define redox reaction mechanisms and rates and a biological approach to identify the microbial communities and corresponding biochemical pathways involved in the production of redox-active metabolites.
The redox cycling and mineralization of metals are dictated by the kinetics and thermodynamics of an intricate network of abiotic and biotic reactions. Furthermore, the metabolic activity of a diverse array of microorganisms may control the speciation, structure and subsequent reactivity of many metals through both direct enzymatic and metabolite-induced reaction pathways.
The operative biogeochemical pathway is a result of synergistic or competing reaction mechanisms, which may not be reflected in the broader redox signature and geochemical profile. For instance, the biomineralization of metals is oftentimes a result of coupled biotic-abiotic pathways, including redox reactions induced by (photo)chemically-active metabolites. The mechanisms (abiotic, enzymatic, metabolite driven) of metal redox transformations and biomineralization are further influenced by the phylogeny and physiology of the functional bacterial and archaeal communities.
The lab also addresses the potential consequences of operative reaction pathways on the stability and reactivity of the ensuing metal biominerals. Thus, the research sits at the interface of environmental geochemistry and microbial ecology to ultimately address the chemical and microbiological controls on the fate and transport of metals that adversely impact both terrestrial and aquatic ecosystems.