LEXEN: Effects of Microbial Activity on Rates of Basalt Alteration

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LEXEN: Effects of Microbial Activity on Rates of Basalt AlterationAbout three quarters of the ocean floor is basalt, providing chemical and physical environments that are suitable for many known microbial species. This ocean crust is a vast source and sink for chemical exchange with the ocean, and basalt/seawater chemical reactions release energy that is a resource for microorganisms. From a global geochemical perspective, the role of microbes in this chemical exchange is an important issue. From an astrobiological perspective, the deep ocean crust is an extremely stable environment and microbes in deep sea basalts may be some of the most primitive organisms on Earth. Study of microbially precipitated minerals and microbial marks in minerals is also relevant to the search for evidence of life on other planetary bodies composed of water and rock. This project explores a new strategy for culturing microorganisms that directly interact with deep sea basalts. A submersible will be used to collect exposed basalts from the sea floor, and to isolate the rocks in sealed containers and introduce tracers into the containers to evaluate contamination. Molecular biology and microscopy techniques will be used to identify organisms and study their interactions with the basalt, and dilution culture methods will be used to search for pure cultures.Mineralogical products of the microbially alterated basalts will be identified by microbeam chemical analysis. ICP-mass spectroscopy will be used to monitor the release of elements from the basalts into solution. This project is relevant to the LExEn objectives (1) of understanding life supporting environments where chemical fluxes are extremely small, (2) of fostering interdisciplinary research - in this case the disciplines of microbiology and geology are closely linked, and (3) of exploring environments on Earth that are likely to exist on planets or moons in the solar system.