The RPL team is conducting laboratory experiments to evaluate the rates and pathways whereby reduced energy sources are produced by the reaction of water with ultramafic rocks and minerals. Experiments focus on temperatures within the known habitable realm for life, and the data is used to build predictive models of the types of metabolisms that could potentially be supported by low-temperature water/rock interactions. We will then examine whether the low flux of nutrients and energy supplied from water/rock interactions is capable of supporting the kinds of organisms that have been and will be (as part of this work) isolated from serpentinite-hosted ecosystems. Target organisms will be introduced into W/R experiments to provide critical insights into the extent to which substrates produced from water/rock interactions can sustain life and whether biological activity may exert direct controls on the resulting reaction pathways, rates, products and potential biosignatures that may result. A second primary objective of the experimental research plan is to gain a more comprehensive understanding of how these electron donors (H2, CH4, formate, CO) are produced during peridotite-water interactions, and how the rate of production of these compounds is affected by environmental conditions such as reaction temperature, rock and water composition, alteration history, and water/rock ratio.
Task 1. Generation of Electron Donors During Water/Rock Interactions
- Abiotic Mineral Hydration Experiments.
- Mechanistic tests of Fe(II)-driven interfacial electron-transfer
- Tracking the origin and fate of hydrocarbons and organic acids.
Task 2: Experimental Inputs/Outputs of Habitability Modeling
Task 3: Water/Rock reactions coupled with microbial activity
Task 4: Microbial physiology of populations sustained by water/rock interaction.
- Isolation of Target Organisms
- Continuous flow reactors for use in monitoring biofilm physiology.
- Production of isotopic biomarkers in laboratory cultures.
- Mineralogical, microscopic, and molecular analyses of incubated minerals.