Investigation 1

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Investigation 1. Developing Methods for Life Detection.

Successful life detection on other planetary bodies requires understanding the interaction between the biomolecules produced by life and their rocky substrates, which may mask, or enhance, detection of organics, and extinct and extant life. Linking the signatures of life to specific metabolisms in modern environments is key to interpreting microbial ecology of ancient rocks from the biosignature record. We propose research on Mars analog environments that develops new approaches for detection of biomolecules, and deepening knowledge of biomolecule-rock substrate interactions. New work will integrate genomics and geochemical signatures in modern volcanic terranes, which in turn will help us interpret specific biosignatures in ancient rocks.


1.1 Life Detection: Mars and Mars Analog Environments

1.1.1 Determining the stability of biomarkers in space environments

Lead: Pascale Ehrenfreund, George Washington University

Summary: Astrobiological, space-exposure experiments have been performed successfully in Earth orbit for over two decades, and these have allowed detailed investigation of the effects of solar UV radiation and galactic cosmic radiation on astrobiological samples. Extended space exposure provides data on multiple samples and insights into the survival of biomarkers beyond Earth, and transport and delivery to planetary surfaces such as Earth and Mars. In-situ experiments in Earth orbit can expand our knowledge of habitability in the solar system.

Figure_1-1

Astrobiological experiments in low Earth orbit. EXPOSE-R (top left) on the International Space Station (ISS), retrieved in 2011 after 20 months space exposure. The metallic vial design of the Miller-Urey experiment will be launched to the ISS in 2013 to investigate prebiotic reactions in microgravity (bottom left). NASA’s O/OREOS spacecraft has successfully performed in 650 km orbit and is still operational (top right). OREOCUBE will be built in 2012, and will provide the capability of daily in situ monitoring of flight samples on the ISS (bottom right).

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1.1.2 Controls on the recovery of mineral-associated biomolecules

Lead: Pascale Ehrenfreund, George Washington University

Summary: Direct detection of biomarkers on Mars or other planetary bodies is critically dependent upon the extractability and sensitivity of the detection methods. It is recognized that clay minerals, thought to represent important repositories of organic material, may impede life/organic detection because of high surface retentivity of organics. This project will investigate adsorption characteristics of biomarkers on clay minerals and develop effective extraction techniques to release adsorbed biological compounds for subsequent detection. These studies will allow us to make informed decisions on developing and executing successful organic detection strategies and techniques on other planetary bodies, including Mars.

Figure_1-2

Field and laboratory research program to advance life detection strategies for Mars exploration: Characterization of mineralogy, organic compounds, and biota from Mars analog regions in their environmental context are crucial to optimize recovery of mineral-associated biomolecules.

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1.2 Modern Microbial Environments

1.2.1 Linking genomic and geochemical signatures of Fe-based microbial life in a volcanic terrain

Leads: Eric Roden, UW-Madison; Eric Boyd, Montana State

Summary: This project will analyze the structure, function, and signatures of Fe redox-based microbial life in two geochemically distinct volcanic springs in Yellowstone National Park (YNP). The central goal is to dissect the composition of gene/genomes, extant microbial species, and isotopic, mineralogical, and organic biosignatures in relation to gradients in Fe redox chemistry and other environmental parameters.

Figure_1-3

Results of pyrosequencing analysis of 16S rRNA genes in materials from the Gap site. BLAST (Altschul et al., 1997) was used to identify the closest pure culture match (genus level affiliation) to representative operational taxonomic units (OTUs). Pie slice size corresponds to relative OTU abundance out of a total of 6276 sequences (ca. 280 bp amplicons of the V4 region, Caporaso et al., 2011). Labels indicate known metabolic capacities for each taxonomic group. Abbreviations: Ferm = Fermentation; Ox = Oxidation; Red = Reduction.

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