Organic host analogues and the search for life on Mars

Marlow, Jeffrey J.; Martins, Zita; Sephton, Mark A.

doi:10.1017/s1473550410000303

Cited by 27 publications

(15 citation statements)

References 178 publications

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“…Each scenario serves as a geochemical analogue to particular past martian conditions-an important consideration in formulating theoretical and experimental hypotheses (Marlow et al, 2011). The specific relevance of each fluid to ancient Mars is discussed below and presented in Table 1, and chemical compositions are provided in Table 2.…”

Section: Martian Fluidsmentioning

confidence: 99%

The Potential for Biologically Catalyzed Anaerobic Methane Oxidation on Ancient Mars

et al. 2014

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This study examines the potential for the biologically mediated anaerobic oxidation of methane (AOM) coupled to sulfate reduction on ancient Mars. Seven distinct fluids representative of putative martian groundwater were used to calculate Gibbs energy values in the presence of dissolved methane under a range of atmospheric CO 2 partial pressures. In all scenarios, AOM is exergonic, ranging from -31 to -135 kJ/mol CH 4 . A reaction transport model was constructed to examine how environmentally relevant parameters such as advection velocity, reactant concentrations, and biomass production rate affect the spatial and temporal dependences of AOM reaction rates. Two geologically supported models for ancient martian AOM are presented: a sulfate-rich groundwater with methane produced from serpentinization by-products, and acid-sulfate fluids with methane from basalt alteration. The simulations presented in this study indicate that AOM could have been a feasible metabolism on ancient Mars, and fossil or isotopic evidence of this metabolic pathway may persist beneath the surface and in surface exposures of eroded ancient terrains.

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Section: Martian Fluidsmentioning

confidence: 99%

The Potential for Biologically Catalyzed Anaerobic Methane Oxidation on Ancient Mars

et al. 2014

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“…Understanding the abiotic and biotic physiochemical processes in terrestrial analogues may provide valuable insight into the occurrence of life on Mars (Marlow et al 2011). Stable conditions in these environments lead to the formation and preservation of secondary mineral deposits, which may harbour chemical compounds produced by living organisms or derived from other biogenic organic compounds reflective of the processes by which the minerals formed or of any biological activity in the environment (such biotic chemicals will be referred to as bio/organic compounds).…”

Section: Introductionmentioning

confidence: 99%

Evidence for biological activity in mineralization of secondary sulphate deposits in a basaltic environment: implications for the search for life in the Martian subsurface

Richardson

Hinman

Scott

2013

International Journal of Astrobiology

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Evidence of microbial activity associated with mineralization of secondary Na-sulphate minerals (thenardite, mirabilite) in the basaltic subsurface of Craters of the Moon National Monument (COM), Idaho were examined by scanning electron microscopy, X-ray diffraction, laser desorption Fourier transform ion cyclotron resonance mass spectrometry (LD-FTICR-MS), Fourier transform infrared spectroscopy (FTIR) and isotope ratio mass spectrometry. Peaks suggestive of bio/organic compounds were observed in the secondary Na-sulphate deposits by LD-FTICR-MS. FTIR provided additional evidence for the presence of bio/organic compounds. Sulphur fractionation was explored to assist in determining if microbes may play a role in oxidizing sulphur. The presence of bio/organic compounds associated with Na-sulphate deposits, along with the necessity of oxidizing reduced sulphur to sulphate, suggests that biological activity may be involved in the formation of these secondary minerals. The secondary Na-sulphate minerals probably form from the overlying basalt through leached sodium ions and sulphate ions produced by bio-oxidation of Fe-sulphide minerals. Since the COM basalts are one of the most comparable terrestrial analogues for their Martian counterparts, the occurrence of biological activity in the formation of sulphate minerals at COM has direct implications for the search for life on Mars. In addition, the presence of caves on Mars suggests the importance of these environments as possible locations for growth and preservation of microbial activity. Therefore, understanding the physiochemical pathways of abiotic and biotic mineralization in the COM subsurface and similar basaltic settings has direct implications for the search for extinct or extant life on Mars.

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“…The reasons for the apparent recent bias toward desert settings are unclear; it could have to do with the sociology of science where researchers focus on a perceived funding source, for example NASA-supported research regarding Martian analogs (DiGregorio, 2002;DiGregorio, 2010;Marlow et al, 2011). A desert focus could also have to do with the greater biogeochemical stability of varnish in arid settings (Dorn, 1998;Dorn, 2007;Dorn, 2009).…”

Section: Introductionmentioning

confidence: 99%