Victoria J. Orphan, Ph.D.

James Irvine Professor of Environmental Science and Geobiology, Division of Geological and Planetary Sciences, California Institute of TechnologyVictoria J. Orphan’s website

PriME Project: Interspecies Interactions, Ecophysiology and Spatial Structuring of Microorganisms Involved in Complex Polymer Degradation in Anoxic Marine Environments

Microbial metabolic cooperation is a fundamental component in the biodegradation of polymers under anoxic conditions. Distinct from aerobic respiration of complex organic carbon, the anaerobic degradation of polymers often involves a synergistic cascade of interdependent microbial metabolisms and syntrophic associations between different microorganisms. The nature and strength of these metabolic interactions, spatial organization of the community, and degree of metabolic redundancy involved in the breakdown of common marine polymers like chitin and alginate in anoxic marine environments is poorly understood. This project will use single cell ecophysiology experiments incorporating complementary molecular and isotopic techniques with cultured model anaerobic microbial communities and environmental samples recovered from anoxic marine environments to study the physico-chemical and biological factors influencing community structure, activity, ecophysiology, interactions and spatial organization associated with marine polymer degradation. 

Victoria Orphan is the James Irvine Professor of Environmental Science and Geobiology at the California Institute of Technology. She received her B.A. in aquatic biology from the University of California, Santa Barbara in 1994, and her Ph.D. in the Ecology, Evolution and Marine Biology program at UCSB in 2001. During 2002–2004, she served as a National Research Council postdoctoral fellow at the NASA Ames Research Center before joining the geobiology faculty in the Division of Geological and Planetary Sciences at Caltech in 2004. She was named the James Irvine Professor in Environmental Science and Geobiology in 2016.

Dr. Orphan’s research incorporates molecular, microscopy and geochemical techniques to study the ecophysiology and interspecies interactions within microbial communities, with an emphasis on microbial assemblages involved in the cycling of methane, sulfur and nitrogen in anoxic ocean ecosystems, deep subsurface and extreme environments. She helped to pioneer novel stable isotope applications using secondary ion mass spectrometry (SIMS and nanoSIMS) for measuring single cell activity and metabolic potential of uncultured microorganisms in environmental samples and has applied these techniques to develop new understanding into the syntrophic interactions and ecophysiology of methane-oxidizing archaea and sulfate-reducing bacteria driving the globally important process of anaerobic oxidation of methane in anoxic ocean sediments. Orphan is a member of the American Academy of Microbiology and was recently named a 2016 MacArthur Fellow.

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