The Search for Life on Mars

McKay, Christopher P.

doi:10.1007/978-94-015-8907-9_14

Cited by 35 publications

(40 citation statements)

References 102 publications

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“…Several classes of organic biomarkers have been proposed based on a number of biological features that are common to all known life-forms on Earth, such as a compartmentalized shape, energy-producing and storage mechanisms, and the use of biomolecules to store hereditary information (McKay, 1997;Parnell et al, 2007;Summons et al, 2008). These biomarkers comprise relatively simple monomers that constitute the building blocks of cells, such as L-amino acids, D-sugars, pigments, and lipids (e.g., isoprenoids, hopanoids), and complex biopolymers such as nucleic acids.…”

Section: Molecular Biomarkersmentioning

confidence: 99%

The Significance of Microbe-Mineral-Biomarker Interactions in the Detection of Life on Mars and Beyond

Röling¹,

Aerts²,

Patty³

et al. 2015

Astrobiology

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The detection of biomarkers plays a central role in our effort to establish whether there is, or was, life beyond Earth. In this review, we address the importance of considering mineralogy in relation to the selection of locations and biomarker detection methodologies with characteristics most promising for exploration. We review relevant mineral-biomarker and mineral-microbe interactions. The local mineralogy on a particular planet reflects its past and current environmental conditions and allows a habitability assessment by comparison with life under extreme conditions on Earth. The type of mineral significantly influences the potential abundances and types of biomarkers and microorganisms containing these biomarkers. The strong adsorptive power of some minerals aids in the preservation of biomarkers and may have been important in the origin of life. On the other hand, this strong adsorption as well as oxidizing properties of minerals can interfere with efficient extraction and detection of biomarkers. Differences in mechanisms of adsorption and in properties of minerals and biomarkers suggest that it will be difficult to design a single extraction procedure for a wide range of biomarkers. While on Mars samples can be used for direct detection of biomarkers such as nucleic acids, amino acids, and lipids, on other planetary bodies remote spectrometric detection of biosignatures has to be relied upon. The interpretation of spectral signatures of photosynthesis can also be affected by local mineralogy. We identify current gaps in our knowledge and indicate how they may be filled to improve the chances of detecting biomarkers on Mars and beyond.

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Section: Molecular Biomarkersmentioning

confidence: 99%

The Significance of Microbe-Mineral-Biomarker Interactions in the Detection of Life on Mars and Beyond

Röling¹,

Aerts²,

Patty³

et al. 2015

Astrobiology

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“…These results indicate that non-bacterial spores (i.e., from an organism of the Eucarya domain) are capable of resisting Martian conditions. Hence, these findings suggest the possibility of finding biomarkers associated with these structures might be considered in the search for Life on Mars [106].…”

Section: Resultsmentioning

confidence: 76%

Survival of Moss Reproductive Structures under Simulated Martian Environmental Conditions and Extreme Thermal Stress: Vibrational Spectroscopic Study and Astrobiological Implications

Gómez¹,

Estébanez²

2016

Astrobiol Outreach

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The principal goal of astrobiology is the search for extraterrestrial life forms. A key aspect is the study of the ability of different kinds of terrestrial organisms to support simulated extraterrestrial environmental conditions. Mosses are multicellular green plants, poorly studied from an astrobiological perspective. In this paper, we report experimental results obtained using two species of moss, which demonstrate that both the spores of the moss Funaria hygrometrica as well as the desiccated vegetative gametophyte shoots of the moss Tortella squarrosa (=Pleurochaete squarrosa) were capable of resisting Simulated Martian Environmental Conditions (SMEC): Mars simulated atmospheric composition 99.9% CO 2 , and 0.6% H 2 O with a pressure of 7 mbars, -73 º C and UV irradiation of 30 mW cm -2 in a wavelength range of 200-400 nm under a limited short time of exposition of 2 hours. After being exposed to SMEC and then transferred to an appropriate growth medium, the F. hygrometrica spores germinated, producing typical gametophyte protonemal cells and leafy shoots. Likewise, detached leaves from SMEC-exposed gametophyte shoots of T. squarrosa retained the ability to produce new protonemata and shoots under suitable growth conditions. Furthermore, we studied the tolerance of these moss structures to a thermal stress of 100 °C for 1 h; in both cases the spores and shoots were capable of resisting this heat treatment. Our study using FT-Raman and FT-IR vibrational spectroscopy demonstrated that neither spores nor shoots apparently suffered significant damage in their biomolecular makeup after being subject to these stress treatments. The implications of these findings for the search of life on Mars are discussed.

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“…In locations where active resurfacing processes occur, such as the ebb and flow of annual snowfall at the Martian polar caps, accumulation rates of entrained dust can be much higher. This is most likely the source of the polar layered terrains and it has been hypothesized that they may contain evidence of former primitive life (McKay, 1997;Cockell and Barlow, 2002;Smith and McKay, 2005).…”

Section: Planetary Drilling and Samplingmentioning

confidence: 99%