Girguis Laboratory @ Harvard University

In the Girguis Lab...

Microbial metabolism involving interactions with solid materials via extracellular electron transfer (EET) plays a key role in environments where diffusion of dissolved ions and volatile compounds is limited, e.g. biofilms, marine sediments or the subsurface biosphere. While the majority of microbes are uncultivable, microbial fuel cells (MFC), which harness energy from microbes that perform EET, are capable of enriching for these uncultivated microorganisms in marine sediments. I propose to conduct community genomic analyses of microbial communities recovered from field-deployed fuel cells to ally phylogenetic identity with functional potential, and to characterize the extent of EET in marine sediments.

Research Interests

Understanding the sources, sinks and cycling of organic matter in marine sediments, in particular:

• Compound specific radiocarbon and stable carbon analysis of sedimentary biomarkers
• The recalcitrance of natural organic compounds in sediments
• The fate of fossil fuel-derived contaminants and their physical and chemical associations with sedimentary organic matter
• The role of microorganisms in the cycling of both natural and anthropogenic organic compounds
• Harnessing energy from the microbial metabolism of carbon in marine sediments

Publications

1. White, H.K., C.M. Reddy and T.I. Eglinton (2007) Relationships between carbon isotopic composition and mode of binding of natural organic matter in selected marine sediments. Organic Geochemistry: doi:10.1016/j.orggeochem.2007.07.008
2. White, H.K., L. Xu, A. L. Lima, T.I. Eglinton and C.M. Reddy (2005) Abundance, composition, and vertical transport of PAHs in marsh sediments. Environmental Science and Technology 39: 8273-8280.
3. White, H.K., C.M. Reddy and T.I. Eglinton (2005) Isotopic constraints on the fate of petroleum residues sequestered in salt marsh sediments. Environmental Science and Technology 39: 2545-2551.
4. Slater, G.F., H.K. White, T.I. Eglinton and C. M. Reddy (2005) Determination of microbial carbon sources in petroleum contaminated sediments using molecular radiocarbon analysis. Environmental Science & Technology 39: 2552-2558.
5. Reddy, C.M., T.I. Eglinton, A.H. Hounshell, H.K. White, L. Xu, R.B. Gaines and G.S. Frysinger (2002) The West Falmouth oil spill after thirty years: The persistence of petroleum hydrocarbons in marsh sediments. Environmental Science and Technology 36: 4754-4760.