Exploring the microbial diversity of a Mars-like Antarctic environment
- Paper number
IAC-11,A1,5,14,x11668
- Author
Dr. Francesca Stomeo, University of the Western Cape, South Africa
- Coauthor
Dr. Stephen Pointing, Hong Kong
- Coauthor
Dr. Marla Tuffin, University of the Western Cape, South Africa
- Coauthor
Prof. Don Cowan, University of the Western Cape, South Africa
- Year
2011
- Abstract
Often described as the terrestrial analogue of the Martian ecosystem, the McMurdo Dry Valleys collectively comprise the most extensive ice-free desert in Antarctica and share the same environmental extremes as Mars: cold and aridity. Microorganisms preserved in ancient permafrost provide a viable model for searching for life on Mars. Permafrost represents a stable environment that allows the prolonged survival of microbial lineages at subzero temperatures. These microbial communities are thought to have retained viability for very long periods and may represent the oldest microorganisms discovered on Earth. In this study, the microbial diversity of soil samples from shallow vertical transects from the slopes of the Miers Valley, East Antarctica, has been investigated through a range of molecular techniques. The transects extend from the soil surface to a depth of approximately 30 cm at the permafrost bounders. The results have been complemented with soil physical chemical data analysis (air and surface soil temperature, air and soil % RH data, water content analysis, soil pH measurements, etc.) in order to understand the abiotic drivers behind the biotic system under study. Our results suggest that depth-dependent microbial communities in the Dry Valleys soils are significantly affected by temperature and % RH. The large % RH gradient between surface and depth is an indicator of potential water availability from the active layer to the surface and sub-surface soil microbial communities. We suggest that water transported to the surface as water vapour is available for microbial populations in the hyper-arid horizon, either as the result of condensation processes or by direct adsorption from the vapour phase. The analysis of terrestrial low organic matter mineral soils, such as the Dry Valleys, provides a valuable model for future Mars missions. Evolutionary traits inferred from molecular characterization in such systems give useful analogs for the search for life on Mars.
- Abstract document
- Manuscript document
(absent)