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originally posted by: Davg80
a reply to: BullwinkleKicksButt
i really wish they things were shorter, do you have a summary of what it was about, Peter Levenda was in another TDL thread here on ATS, was actually putting me right on a few things, sounds much more a pro than Tom.
originally posted by: BullwinkleKicksButt
Probably mean things like FTIR, TGA, DSC, Chromatography etc.
The Rio Tinto acid mine drainage-dominated region features numerous settings where sulfates and iron oxide/hydroxide species have formed (Amils et al. 2007; Fernández-Remolar et al. 2005, 2011). These studies have shown that both inorganic and biologic activity plays a role in formation of many of the precipitates and efflorescent salts in this region. Given the association of microorganisms such as Acidithiobacillus ferrooxidans with the aqueous oxidation of sulfides in Rio Tinto (Amils et al. 2002), deposits of sulfate precipitates on Mars represent possible sites to search for extinct life on that planet.
Lab and field investigations of iron-rich aqueous precipitates and alteration environments are needed to provide ground-truthing for identification of these minerals on Mars and to improve our ability to connect the martian mineralogy to geochemical environments. For this study, we used three techniques for a mineralogical investigation that are currently employed or planned for landed missions on Mars: X-ray diffraction (XRD), visible-near infrared (VNIR) reflectance spectroscopy, and laser Raman spectroscopy (LRS).
Few scientists would deny that the search for life on planets beyond our own should be microbial in nature. Such expectations have fueled numerous studies on extreme environments as analogs for extraterrestrial habitable environments that can help predict whether life existed or still exists beyond our planet. Many of these extreme analog environments are dominated by chemolithotrophy as the principal form of metabolism and include examples such as Iron Mountain in California (Edwards et al., 1998; Schrenk et al., 1998) and the Río Tinto (RT) (Amils et al., 2007; González-Toril et al., 2003a, 2003b) in southwestern Spain. The RT flows 100 km through the world's largest pyritic belt and is distinct from other extremely acidic, iron-rich sites in that both chemolithotrophy and phototrophy drive the metabolic machinery of this environment. As a consequence, bacteria, archaea and eukaryotes often occur in abundance (López-Archilla and Amils, 1999; Amaral-Zettler et al., 2002; González-Toril et al., 2003b; Aguilera et al., 2007). Furthermore, it is an ancient ecosystem and geological evidence suggests that the microbial communities that exist there today are similar to those that existed millions of years ago (Fernández-Remolar et al., 2005). Given its antiquity and size, one might predict an absence of a ‘rare biosphere' (Sogin et al., 2006) characterizing microbial diversity there, as the most successful organisms might be expected to outcompete and dominate in this extreme habitat. Before this investigation and an earlier study (Palacios et al., 2008) that focused strictly on bacteria, we understood bacterial diversity in the RT to be limited to a small number of taxa that dominate the river (González-Toril et al., 2003b; Amils et al., 2004). These include the main iron-oxidizing and -reducing bacteria Leptospirillum ferrooxidans, Acidithiobacillus ferrooxidans and Acidiphilium spp. that help to shape the extreme conditions found in the RT (Amils et al., 2002). More recently, García-Moyano et al. (2007) reported on the bacterial and archaeal composition of floating macroscopic filaments. These investigators found a total of seven operational taxonomic units (OTUs) with an upper estimate of 36 for the total sequence diversity present. However, modern molecular high-throughput sequenced-based approaches to microbial diversity have transformed our ability to measure ecological diversity in the microbial realm and have revealed many diverse low-abundance taxa (Palacios et al., 2008) even in extreme environments such as the RT.