Impact‐induced microbial endolithic habitats
Charles S. Cockell,Charles S. Cockell,Pascal Lee,Gordon R. Osinski,Gerda Horneck,Paul A. Broady +5 more
TLDR
In this paper, the authors describe how heavily shocked gneissic crystalline basement rocks exposed at the Haughton impact structure, Devon Island, Nunavut, Arctic Canada, are hosts to endolithic photosynthetic microorganisms in significantly greater abundance than lesser-shocked or unshocked Gneisses.Abstract:
Asteroid and comet impacts on Earth are commonly viewed as agents of ecosystem destruction, be it on local or global scales. However, for some microbial communities, impacts may represent an opportunity for habitat formation as some substrates are rendered more suitable for colonization when processed by impacts. We describe how heavily shocked gneissic crystalline basement rocks exposed at the Haughton impact structure, Devon Island, Nunavut, Arctic Canada, are hosts to endolithic photosynthetic microorganisms in significantly greater abundance than lesser-shocked or unshocked gneisses. Two factors contribute to this enhancement: (a) increased porosity due to impact fracturing and differential mineral vaporization, and (b) increased translucence due to the selective vaporization of opaque mineral phases. Using biological ultraviolet radiation dosimetry, and by measuring the concentrations of photoprotective compounds, we demonstrate that a covering of 0.8 mm of shocked gneiss can provide substantial protection from ultraviolet radiation, reducing the inactivation of Bacillus subtilis spores by 2 orders of magnitude. The colonisation of the shocked habitat represents a potential mechanism for pioneer microorganisms to invade an impact structure in the earliest stages of post-impact primary succession. The communities are analogous to the endolithic communities associated with sedimentary rocks in Antarctica, but because they occur in shocked crystalline rocks, they illustrate a mechanism for the creation of microbial habitats on planetary surfaces that do not have exposed sedimentary units. This might have been the case on early Earth. The data have implications for the microhabitats in which biological signatures might be sought on Mars.read more
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Living at the Extremes: Extremophiles and the Limits of Life in a Planetary Context.
Nancy Merino,Heidi S. Aronson,D.P. Bojanova,Jayme Feyhl-Buska,Michael L. Wong,Shu Zhang,Donato Giovannelli +6 more
TL;DR: The current state of knowledge for the biospace in which life operates on Earth is reviewed and discussed in a planetary context, highlighting knowledge gaps and areas of opportunity.
Journal ArticleDOI
Biosignatures on Mars: What, Where, and How? Implications for the Search for Martian Life
Frances Westall,Frédéric Foucher,Nicolas Bost,Marylène Bertrand,Damien Loizeau,Jorge L. Vago,Gerhard Kminek,F. Gaboyer,Kathleen A. Campbell,Jean-Gabriel Bréhéret,Pascale Gautret,Charles S. Cockell +11 more
TL;DR: It is hypothesized that, given the lack of long-term, continuous habitability, if martian life developed, it was (and may still be) chemotrophic and anaerobic, and the biogenicity of these signatures is evaluated by comparing them to possible abiotic features.
Journal ArticleDOI
Effects of a Simulated Martian UV Flux on the Cyanobacterium, Chroococcidiopsis sp. 029
TL;DR: Under the intense martian UV flux the morphological signatures of life can persist even after viability, enzymatic activity, and pigmentation have been destroyed, showing implications for the survival of diverse microbial contaminants dispersed during the course of human exploratory class missions on the surface of Mars.
Journal ArticleDOI
Zones of photosynthetic potential on Mars and the early Earth
Charles S. Cockell,John A. Raven +1 more
TL;DR: In this article, the authors used a simple radiative transfer model to study four micro-habitats in which such a theoretical Martian Earth-like photosynthetic Zone (MEPZ) might exist.
Journal ArticleDOI
Evidence for Hesperian impact-induced hydrothermalism on Mars
Giuseppe A. Marzo,Alfonso F. Davila,Alfonso F. Davila,Livio L. Tornabene,James M. Dohm,Alberto G. Fairén,Christoph Gross,Thomas Kneissl,Janice L. Bishop,Ted L. Roush,Christopher P. McKay +10 more
TL;DR: In this paper, spectral and morphologic evidence of impact-induced hydrothermal activity was found in Toro crater, which is located on the northern edge of the Syrtis Major Volcanic Plains.
References
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