SGER: Design, Construction and Testing of Prototype Instrument for Contamination-Free Sampling of Crustal Fluids from Deep-Sea Boreholes

University Of Hawaii, Honolulu

Investigators

Abstract

This is a Small Grant for Exploratory Research (SGER) award to support design, building and testing of a Downhole Sampler (DS) for ocean crustal fluids; subsequent versions of the DS will also permit downhole in situ incubations. Direct collection of fluids at the bottom of the borehole should avoid the potential changes imposed on the fluid composition during its ascent to the surface. The DS will be used to study the microbial community structure in the context of geochemical and physical conditions of the basement crust. The PI, in collaboration with Craig Taylor's group at the Woods Hole Oceanographic Institution, will demonstrate the feasibility of collecting uncontaminated fluids from aging, sediment-buried ocean basement crust. Development of a new sampling device that can collect contamination-free samples from this extreme environment is a risky endeavor. Accordingly, the team will: 1) Perform preliminary shore-based borehole simulations; 2) use dissolved, particle and microbial tracers to test the ability of the inlet system to obtain clean samples; and 3) compare the chemistry, microbial diversity, and community structure of pristine crustal fluids at the bottom of the borehole with those collected throughout the borehole and with seawater in order to establish the nature and magnitude of any influence of the borehole on the ascending fluids. The proposed work represents a pioneer attempt to explore the biosphere present in the sub-sea floor. The potential to elucidate the metabolic processes and ecology of microorganisms with authentic samples from this vast and unexplored new environment is high, as is the potential for discovery of novel organisms with new metabolic pathways.