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Project Progress

Low temperature hydrothermal ocean fluids (<100°C), circulate everywhere within the porous and permeable volcanic rocks of the upper ocean basement, providing temperatures and chemical gradients that form plausible habitats for a variety of microbial communities. However, few direct tests have been carried out in buried basement rocks or fluids. Nevertheless, there is growing evidence that a substantial subseafloor biosphere extends throughout the immense volume of aging basement underlying the global system of mid-ocean ridge (MOR) flanks and ocean basins. Since most MOR flank and ocean basin basement is buried under thick, impermeable layers of sediment, the fluids circulating within the underlying ocean basement are usually inaccessible for direct studies. Circulation Obviation Retrofit Kit (CORK) observatories affixed to Integrated Ocean Drilling Program (IODP) boreholes offer an unprecedented opportunity to study biogeochemical properties and microbial diversity in circulating fluids from deep ocean basement.

A. We have secured major funding ($1.2 M) from NSF-Microbial Research (a Microbial Observatory grant) to continue our investigation into the deep-subsurface biosphere via CORK Observatories at the Juan de Fuca Ridge flanks. We were able to leverage UH-NAI research funds and personnel, as well as EO opportunities to obtain this NSF funding.

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Modification of our existing seafloor CORK instrumentation sled (the GeoMICROBE sled) and associated components is underway. The GeoMICROBE system will provide the primary in situ sampling and analytical platform for the field efforts. Engineers, submersible pilots and PIs have identified solution options for all issues. We are currently pushing these toward working mechanical drawings; we are also in negotiations with electronic/software engineers and parts vendors.

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B. Our success with the Juan de Fuca Ridge flank subsurface biosphere project and associated instrumentation development has led to the high probability of additional significant funding (~$1.6 M) to UH-NAI investigators James Cowen and Brian Glazer to fund their participation in a related deep biosphere project to focus on North Pond area near the Mid Atlantic Ridge. This is a multi-NAI collaboration let by Katrina Edwards (part of the MBL/Sogin NAI.).

C. Deep subseafloor tracer transport project [”Collaborative Research: A three-dimensional, subseafloor, IODP observatory network in the northeastern Pacific Ocean, and initiation of large-scale, cross-hole experiments Tracer transport study”]. This project is an ambitious study of the circulation of fluids within the sediment-buried flanks of a mid-ocean ridge (Juan de Fuca Ridge) and will involve the injection of dissolved and particle tracers into the basement via injection boreholes and the monitoring of the tracers at several boreholes at spatial scales of 10s to 1,000 of meters and time scales of hours to years (Figure 3).

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The particle tracers (fluorescent microspheres and stained ocean microbes) will be used as proxies of potential basement microorganisms. The team (UH-NAI microbial geochemists and collaborating hydrogeologists and geochemists from other institutions) is working through infrastructure issues in this complex project. A submersible expedition to seal (cement) the primary project CORK observatories is set for departure in August 2007. Tracer injections are expected in 2008 or 2009.