HR: 10:35h
AN: P42B-02    [Abstracts]
TI: Exploration of a Subsurface Biosphere in a Volcanic Massive Sulfide: Results of the Mars Analog Rio Tinto Drilling Experiment
AU: * Stoker, C R
EM: cstoker@mail.arc.nasa.gov
AF: NASA Ames Research Center, M.S. 245-3, Moffett Field, CA 94035 United States
AU: Stevens, T
EM: tstevens@gorge.net
AF: Portland State University, Dept. of biological sciences, Portland, OR 90000 United States
AU: Amils, R
EM: ramils@cbm.us.es
AF: Centro de Astrobiolgia, Torrejon de Ardoz, Madrid, 10000 Spain
AU: Fernandez, D
EM: fernandezd@inta.es
AF: Centro de Astrobiolgia, Torrejon de Ardoz, Madrid, 10000 Spain
AB: Biological systems on Earth require three key ingredients-- liquid water, an energy source, and a carbon source, that are found in very few extraterrestrial environments. Previous examples of independent subsurface ecosystems have been found only in basalt aquifers. Such lithotrophic microbial ecosystems (LME) have been proposed as models for steps in the early evolution of Earth's biosphere and for potential biospheres on other planets where the surface is uninhabitable, such as Mars and Europa.. The Mars Analog Rio Tinto Experiment (MARTE) has searched in a volcanic massive sulfide deposit in Rio Tinto Spain for a subsurface biosphere capable of living without sunlight or oxygen and found a subsurface ecosystem driven by the weathering of the massive sulfide deposit (VMS) in which the rock matrix provides sufficient resources to support microbial metabolism, including the vigorous production of H2 by water-rock interactions. Microbial production of methane and sulfate occurred in the sulfide orebody and microbial production of methane and hydrogen sulfide continued in an anoxic plume downgradient from the sulfide ore. Organic carbon concentrations in the parent rock were too low to support microbes. The Rio Tinto system thus represents a new type of subsurface ecosystem with strong relevance for exobiological studies. Commercial drilling was used to reach the aquifer system at 100 m depth and conventional laboratory techniques were used to identify and characterize the biosphere. Then, the life search strategy that led to successful identification of this biosphere was applied to the development of a robotic drilling, core handling, inspection, subsampling, and life detection system built on a prototype planetary lander that was deployed in Rio Tinto Spain in September 2005 to test the capability of a robotic drilling system to search for subsurface life. A remote science team directed the simulation and analyzed the data from the MARTE robotic drill. The results of this experiment have important implications for the strategy for searching for life on Mars.
UR: http://www.marteproject.com
DE: 5200 PLANETARY SCIENCES: ASTROBIOLOGY
SC: Planetary Sciences [P]
MN: Fall Meeting 2005