Evidence of ancient microbial activity on Mars

Wallis, Jamie; Wickramasinghe, N. C.; Wallis, Daryl H.; Miyake, N.; Wallis, M. K.; Hoover, Richard B.

doi:10.1117/12.2186518

Cited by 2 publications

(3 citation statements)

References 38 publications

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“…Several examples could be cited of bacteria functioning in media subject to very high hydrostatic pressure: barotolerant or barophilic bacteria function normally at depths of 5.5 km in the sea corresponding to a pressure of 600 atmospheres (Parkes et al). Bacteria recovered from drills of the Siljan crater at depths of 6.7 km evidently thrive in sludge subject to even higher pressures [8,9]. Such pressures of ~10 3 atmospheres are interestingly close to the limits set by the tensile strength of water-ice.…”

Section: Introductionmentioning

confidence: 66%

Rosetta Studies of Comet 67P/Churyumov–Gerasimenko: Prospects for Establishing Cometary Biology

Nc¹,

Wainwright²,

Smith³

et al. 2015

Astrobiol Outreach

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We discuss a wide range of data emerging from the Rosetta Mission that all point indirectly to biological activity in Comet 67P/Churyumov-Gerasimenko. The existence of cracks and fissures on a smooth surface terrain apparently resealed, as well as early outgassing activity are consistent with the existence of subsurface lakes in which biological activity builds up high pressures of volatile gases that sporadically ruptures a frozen icy crust. While microorganisms probably require liquid water bodies for their early colonising of a comet, they can inhabit cracks in ice and sub-crustal snow, especially if they contain antifreeze salts and biopolymers. Some organisms metabolise at temperatures as low as 230 K, explaining the coma of Comet 97P out at 3.9AU and our prediction is that they would become increasingly active in the near-surface layers as the comet approaches its 1.3 AU perihelion. The detection of an overwhelming abundance of complex organic molecules at the surface by Philae and through IR imaging by the Rosetta orbiter is most significant.

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Section: Introductionmentioning

confidence: 66%

Rosetta Studies of Comet 67P/Churyumov–Gerasimenko: Prospects for Establishing Cometary Biology

Nc¹,

Wainwright²,

Smith³

et al. 2015

Astrobiol Outreach

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“…Finally photosynthetic microorganisms containing arxA capable of oxidizing arsenite in anoxic environments are potential candidate metabolisms capable of surviving beyond the Earth, on or within other planet(oid)s such as Mars and Europa. The recent finding of arsenic minerals within the Tissint Martian meteorite raises the possibility of a primitive microbial arsenic metabolism having once occurred on Mars (Wallis and Wickramasinghe, 2015). …”

Section: Resultsmentioning

confidence: 99%

“…This would have provided the necessary niche that allowed the evolution of autotrophic pathways for arsenite oxidation. Finally, recent discoveries where both arsenic and microbial organic signatures found in a Mars (Wallis and Wickramasinghe, 2015) meteoroid and within stromatolites (Sforna et al ., 2014) from 2.7 b.y.a., raises the question on how arsenite may have played a role in arsenotrophy as life evolved within arsenic rich environments.…”

Section: Introductionmentioning

confidence: 99%

The genetic basis of anoxygenic photosynthetic arsenite oxidation

Hernandez-Maldonado

Sanchez‐Sedillo

Stoneburner

et al. 2016

Environmental Microbiology

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Summary ‘Photoarsenotrophy’, the use of arsenite as an electron donor for anoxygenic photosynthesis, is thought to be an ancient form of phototrophy along with the photosynthetic oxidation of Fe(II), H2S, H2 and NO2−. Photoarsenotrophy was recently identified from Paoha Island's (Mono Lake, CA) arsenic-rich hot springs. The genomes of several photoarsenotrophs revealed a gene cluster, arxB2AB1CD, where arxA is predicted to encode for the sole arsenite oxidase. The role of arxA in photosynthetic arsenite oxidation was confirmed by disrupting the gene in a representative photoarsenotrophic bacterium, resulting in the loss of light-dependent arsenite oxidation. In situ evidence of active photoarsenotrophic microbes was supported by arxA mRNA detection for the first time, in red-pigmented microbial mats within the hot springs of Paoha Island. This work expands on the genetics for photosynthesis coupled to new electron donors and elaborates on known mechanisms for arsenic metabolism, thereby highlighting the complexities of arsenic biogeochemical cycling.

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Evidence of ancient microbial activity on Mars

Cited by 2 publications

References 38 publications

Rosetta Studies of Comet 67P/Churyumov–Gerasimenko: Prospects for Establishing Cometary Biology

Rosetta Studies of Comet 67P/Churyumov–Gerasimenko: Prospects for Establishing Cometary Biology

The genetic basis of anoxygenic photosynthetic arsenite oxidation

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