investigationofthespatialrelationships
Kimberly KuhlmanNASA ExobiologyInvestigation of the Spatial Relationships of Bacteria Within Rock VarnishBased on our phylogenetic analyses of the bacteria associated with rock varnish in the Mojave, Sonoran and Atacama Deserts, we hypothesize that the community structure within the varnish is reminiscent of the cryptoendolithic communities found in other systems, albeit on a much smaller scale. These communities in varnish have been shown to be different from the surrounding soil. A cryptoendolithic community has very recently been characterized in volcanic glass using 16S rDNA and fluorescence in situ hybridization (FISH) by Herrera, et al., 2009 where photosynthetically active radiation (PAR) only penetrates about 50 micrometers in solid obsidian.
The goals of the proposed work are to characterize the novel microbial communities present in rock varnishes from these three locations and assess the spatial relationships between the organisms found and the mineralogy of the varnish. The objectives of the proposed work are to 1) develop the methods required for investigating communities in varnish using fluorescence in situ hybridization (FISH) probes, 2) collect fresh samples of rock varnish from Parker, AZ, Cima, CA and Yungay, Chile for preparation of new clone libraries 3) generate FISH probes based upon our clone libraries, 4) use these probes to enumerate the different bacteria present in powdered varnish and finally 5) use the FISH probes to visualize the spatial relationships between the different bacteria in petrographic thin sections of rock varnish. This work will not only enhance our understanding of the relationship between rock varnish and the microbial life inhabiting what has been shown to be a niche environment, but it will have implications for the development of techniques and instruments to look for microbes in purported rock varnish and other coatings on Mars and for better understanding how microbes may have evolved to inhabit Mars-like environments on Earth.
The goals of the proposed work are to characterize the novel microbial communities present in rock varnishes from these three locations and assess the spatial relationships between the organisms found and the mineralogy of the varnish. The objectives of the proposed work are to 1) develop the methods required for investigating communities in varnish using fluorescence in situ hybridization (FISH) probes, 2) collect fresh samples of rock varnish from Parker, AZ, Cima, CA and Yungay, Chile for preparation of new clone libraries 3) generate FISH probes based upon our clone libraries, 4) use these probes to enumerate the different bacteria present in powdered varnish and finally 5) use the FISH probes to visualize the spatial relationships between the different bacteria in petrographic thin sections of rock varnish. This work will not only enhance our understanding of the relationship between rock varnish and the microbial life inhabiting what has been shown to be a niche environment, but it will have implications for the development of techniques and instruments to look for microbes in purported rock varnish and other coatings on Mars and for better understanding how microbes may have evolved to inhabit Mars-like environments on Earth.
