Research
Water-Rock-Microbe Interactions
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The vast majority of prokaryotes on Earth live in subsurface environments, and their abundance and activity has important consequences for global biogeochemical processes. The impact of microbial communities in sedimentary habitats, or in hydrologically active oceanic crust, on the chemical exchange between global reservoirs remains poorly constrained however. One of our major interests is the exchange of carbon and energy between geological environments and the microbial communities inhabiting them.
Water-Rock-Microbe Interactions
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The vast majority of prokaryotes on Earth live in subsurface environments, and their abundance and activity has important consequences for global biogeochemical processes. The impact of microbial communities in sedimentary habitats, or in hydrologically active oceanic crust, on the chemical exchange between global reservoirs remains poorly constrained however. One of our major interests is the exchange of carbon and energy between geological environments and the microbial communities inhabiting them.
Serpentinization Environments
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In serpentinization environments, the reaction of ultramafic rocks with water results in alkaline fluids containing high concentrations of abiogenic hydrogen, methane, short-chain hydrocarbons, and formate. These highly reactive systems are widespread on earth and are responsible for approximately 70% of the mid-ocean fluxes of hydrogen and methane to the ocean. Both gasses provide abundant thermodynamic energy to fuel chemolithoautotrophy. The extent to which they are utilized by microbial communities can, in turn, exert a strong influence on their fluxes to the ocean. Serpentinization systems can be found anywhere mantle rocks are exposed to water, including deep in the ocean or as part of continental springs
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Serpentinization Environments
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In serpentinization environments, the reaction of ultramafic rocks with water results in alkaline fluids containing high concentrations of abiogenic hydrogen, methane, short-chain hydrocarbons, and formate. These highly reactive systems are widespread on earth and are responsible for approximately 70% of the mid-ocean fluxes of hydrogen and methane to the ocean. Both gasses provide abundant thermodynamic energy to fuel chemolithoautotrophy. The extent to which they are utilized by microbial communities can, in turn, exert a strong influence on their fluxes to the ocean. Serpentinization systems can be found anywhere mantle rocks are exposed to water, including deep in the ocean or as part of continental springs
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Russell and Martin, 2004, Trends in Biochem Sci
Transition from "geoenergetics" to "bioenergetics"
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Where, and how, did life originate? There are several arguments to be made that the transition from geologically produced organic molecules to biologically produced organic molecules occurred at alkaline, serpentinite-hosted hydrothermal vents.
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Knowing the conditions that lead to the abiotic synthesis of organic compounds is critical to understanding the conditions in which life arose. By looking at the concentrations and isotopic signatures of organic molecules in places like the Lost City hydrotheramal field, we can help to identify the environments most conducive to abiotic synthesis.
New Methods
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There are approximately 2 x 10^15 organic molecules in 1 mL of water, and each of those molecules carries with it structural and isotopic information. This data can be used to track the source and fate of carbon as it cycles through the environment.
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Developing new methods provides fresh insights. A current push in our laboratory is to isolate small polar organic molecules for isotope (13C, 14C) analysis. These molecules (e.g. organic acids) can be particularly important to carbon cycling in subsurface and anaerobic environments.