Rock Surfaces as Life Indicators: New Ways to Demonstrate Life and Traces of Former Life

Gorbushina, Anna A.; Krumbein, Wolfgang E.; Volkmann, Marc

doi:10.1089/15311070260192273

Cited by 72 publications

(31 citation statements)

References 38 publications

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“…If a considerable amount of inorganic material is deposited onto the fungal hyphae, then decomposition can be inhibited, and fossilization and preservation stimulated. Whole colonies can, in fact, be "mummified" (Gorbushina et al 2002). Fungi in subaerial rock environments-like hot and cold deserts with varying extremes in microclimatic conditions including irradiation, salinity, pH, humidity and temperatureprotect themselves by producing extracellular polymeric substances (EPS) and/or mucilaginous polysaccharides that contain clay particles (Gorbushina 2003;Volkmann et al 2003;Gadd 2007).…”

Section: Preservation Of Subseafloor Fungal Coloniesmentioning

confidence: 99%

Fungal colonies in open fractures of subseafloor basalt

et al. 2013

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The deep subseafloor crust is one of the few great frontiers of unknown biology on Earth and, still today, the notion of the deep biosphere is commonly based on the fossil record. Interpretation of palaeobiological information is thus central in the exploration of this hidden biosphere and, for each new discovery, criteria used to establish biogenicity are challenged and need careful consideration. In this paper networks of fossilized filamentous structures are for the first time described in open fractures of subseafloor basalts collected at the Emperor Seamounts, Pacific Ocean. These structures have been investigated with optical microscopy, environmental scanning electron microscope, energy dispersive spectrometer, X-ray powder diffraction as well as synchrotron-radiation X-ray tomographic microscopy, and interpreted as fossilized fungal mycelia. Morphological features such as hyphae, yeastlike growth and sclerotia were observed. The fossilized fungi are mineralized by montmorillonite, a process that probably began while the fungi were alive. It seems plausible that the fungi produced mucilaginous polysaccharides and/or extracellular polymeric substances that attracted minerals or clay particles, resulting in complete fossilization by montmorillonite. The findings are in agreement with previous observations of fossilized fungi in subseafloor basalts and establish fungi as regular inhabitants of such settings. They further show that fossilized microorganisms are not restricted to pore spaces filled by secondary mineralizations but can be found in open pore spaces as well. This challenges standard protocols for establishing biogenicity and calls for extra care in data interpretation.

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Section: Preservation Of Subseafloor Fungal Coloniesmentioning

confidence: 99%

Fungal colonies in open fractures of subseafloor basalt

et al. 2013

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“…In these mineral crusts, the remains of the active microorganisms are preserved and easily detectable. Rock varnish could form on Mars and should be targeted on upcoming missions (Gorbushina et al, 2002).…”

Section: Introductionmentioning

confidence: 99%

Chemical Composition of Micrometer-Sized Filaments in an Aragonite Host by a Miniature Laser Ablation/Ionization Mass Spectrometer

et al. 2015

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Detection of extraterrestrial life is an ongoing goal in space exploration, and there is a need for advanced instruments and methods for the detection of signatures of life based on chemical and isotopic composition. Here, we present the first investigation of chemical composition of putative microfossils in natural samples using a miniature laser ablation/ionization time-of-flight mass spectrometer (LMS). The studies were conducted with high lateral (∼15 μm) and vertical (∼20-200 nm) resolution. The primary aim of the study was to investigate the instrument performance on micrometer-sized samples both in terms of isotope abundance and element composition. The following objectives had to be achieved: (1) Consider the detection and calculation of single stable isotope ratios in natural rock samples with techniques compatible with their employment of space instrumentation for biomarker detection in future planetary missions. (2) Achieve a highly accurate chemical compositional map of rock samples with embedded structures at the micrometer scale in which the rock matrix is easily distinguished from the micrometer structures. Our results indicate that chemical mapping of strongly heterogeneous rock samples can be obtained with a high accuracy, whereas the requirements for isotope ratios need to be improved to reach sufficiently large signal-to-noise ratio (SNR).

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“…Their amazing survival abilities are likely due to a complex of adaptations: their melanization, thick walls and meristematic growth, among others, which protect them against both extreme temperature and desiccation Dadachova and Casadevall 2008). Because of these properties, they have triggered interest in the fields of astro-and exobiology (Gorbushina et al 2002;Gorbushina 2003;Onofri et al 2004Onofri et al , 2007Onofri et al , 2008. A recent study reported evidence for the survival of these fungi to space conditions in growth experiments carried out on the International Space Station (Onofri et al , 2009.…”

Section: Introductionmentioning

confidence: 99%