Biology – Quantitative Biology – Genomics
Scientific paper
Dec 2010
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2010agufm.p11d..06w&link_type=abstract
American Geophysical Union, Fall Meeting 2010, abstract #P11D-06
Biology
Quantitative Biology
Genomics
[0406] Biogeosciences / Astrobiology And Extraterrestrial Materials, [0456] Biogeosciences / Life In Extreme Environments, [0465] Biogeosciences / Microbiology: Ecology, Physiology And Genomics, [5200] Planetary Sciences: Astrobiology
Scientific paper
The primary targets for astrobiology investigations of other solar system bodies are Mars as well as Europa and Enceladus. Extremely cold temperatures characterize these targets, and as such, the best terrestrial analogues may be the Earth's polar regions; the Canadian high Arctic offers several unique cryoenvironments that resemble the conditions that are known, or are suspected, to exist on Mars. This presentation will describe our recent research examining microbial life in the unique cold saline springs and permafrost habitats on Axel Heiberg Island with the overall goals of determining the low temperature limits of microbial life on Earth and whether microbial communities inhabiting such cryoenvironments (subzero habitats) are active at ambient subzero tem-peratures. The presentation will focus on the microbiology and geochemistry of the Lost Hammer Spring (LH) site which provides a model of how a methane seep can form in cryoenvironments characterized by thick extensive permafrost in an area with an average annual air temperature of -15C and air temperatures below -40C common during the winter months and provides a mechanism that could possibly be contributing to reported methane plumes or hotspots on Mars. This highly unique hypersaline (23% salinity), subzero (-5C) environment supports a viable microbial community capable of activity at temperatures as low as -10C; in the LH spring, the methane itself can act as an energy and carbon source for sustaining anaerobic methane oxidation-based microbial metabolism, rather than methanogenesis, within these extreme environmental constraints. It has been recently postulated that the ~10 ppb CH4 reported in the Mars atmosphere may originate from localized “hotspots” or “plumes” of methane arising from the Martian surface. The origin of these plumes is under debate and could be attributable to either geological or biological sources, the latter including methanogenesis by microbial communities inhabiting the Martian subsurface. Sites characterized by high methane dis-charges and high salinities in cryoenvironments such as LH have not been described in terrestrial settings, as previous reports of methane seeps have been restricted to deep sea marine sediment sites where methane hydrates occur. Gas composition (C1-C4 hydrocarbons, He, H2, O2, N2, Ar, & CO2) and stable isotope (d13C and d2H values using compound specific isotope analysis) analyses of the saline spring gas samples has revealed the small amounts of hydro-carbons in gases exsolving from the Gypsum Hill springs (0.38 to 0.51% CH4) were compositionally and isotopically consistent with microbial methanogenesis and possible methanotrophy while the major gas emitted from the LH spring is methane (~50 %) with carbon and hydrogen isotope signatures consistent with a thermogenic origin. These sites are currently being used to field test life detection instruments, including a prototype cavity ring down spectroscopy (CRDS) system for CH4 analyses.
Andersen Timothy D.
Greer Christopher
Mykytczuk N.
Niederberger Thomas
Onstott Tullis C.
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