Geobiological Comparisons of Preservation Potential within Hypersaline Mineral-Microbe Systems

The purpose of these investigations is to show comparative measurements between known biological sources of biomarkers and biosignatures and how they can be independently verified, within instrumentation limits, by laboratory investigations analogous to future surface missions to Mars and Europa. Precipitated hypersaline mineralogy can provide a biotic record of microbial activity and habitation within evaporating lake systems. The extent of microbial preservation is a direct relationship between the magnitudes of aqueous activity post-precipitation, original or in-situ biological habitats, dissolution events due to chemical weathering, and organic matter degradation due to UV exposure and desiccation. Chemical biomarkers and physical biosignatures to be quantified and correlated based from preserved DNA as the most sensitive biomarker to more recalcitrant biomarkers such as lipids and Total Organic Carbon (TOC). Moreover the timing of cell movement during nutrient cycling within specific evaporite minerals can be associated to the formation of physical biosignatures as a function of already active and abundant biomarkers allowing for relative timelines of biogenic actions (e.g., nutrient cycling, cell division) to be correlated together. Our investigation has compared hypersaline biotic activity within different photosynthetic and chemosynthetic settings to quantify preservation and detection profiles given measured DNA as the source validation standard and micron-scale Raman measurements for specific paleoenvironmental mineral sampling.