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Executive Summary

Research and education/outreach efforts of our team center around the question of life detection on Mars. Thus, we have analyzed when and where habitable environments may have formed over Mars’ history. This has included atmospheric chemical studies that have revealed that organic aerosols may have had a larger influence on the climate than previously estimated early in Mars history. Through study of the interaction between Martian geodynamic and hydrologic processes and via modeling, we deduce that features mapped as potential shorelines up to 2 km high could indeed be paleoshorelines from large, vanished oceans. We conclude that Martian landslides in Valles Marineris were probably dry and propose that at least some of the Martian outburst floods were triggered by large impacts. Examination of several terrestrial channels that share features with channels on Mars has ruled out channel formation by groundwater discharge alone. These analyses provide important constraints for development of plausible models for Martian topography, information that is being used to predict sites with long term water that may have sustained life.

Given water, the next consideration for habitable environments is a readily utilizable energy supply. Thus, we have turned to Earth-based biomes that are populated by chemoautotrophic organisms that utilize iron and/or sulfur to provide possible analogs for present or past Martian biomes. Our study sites include groundwater seeps, one of which is a channel site chosen for its apparent geomorphological similarity to channels on Mars, and surface, subsurface, and sub-oceanic sites characterized by geochemical disequilibria involving iron and/or sulfur. We have defined the membership of microbial communities at these sites, quantified organism activities in situ, and monitored population dynamics. We have uncovered certain biogeochemical processes that underpin these systems, including the role of inorganic aqueous molecular clusters as substrates for microbial growth. This work has included analysis of fine scale and molecular biomarkers and has taken advantage of newly developed culturing strategies and state-of-the art geochemical, isotopic, genomic, biochemical, and proteomic methods.

Our EPO efforts integrate aspects of this research into educational modules for middle, and high school classes and after school groups. We have begun field-testing materials in schools and community centers in northern California communities that contain large African American, Latino, and Asian/Pacific Islander populations, including Berkeley, Oakland, and Richmond. Our hope is that the excitement associated with ongoing Mars exploration can be harnessed to motivate students to understand scientific concepts central to the problems of detecting life in a foreign world.