1
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Runge EA, Mansor M, Kappler A, Duda JP. Microbial biosignatures in ancient deep-sea hydrothermal sulfides. GEOBIOLOGY 2023; 21:355-377. [PMID: 36524457 DOI: 10.1111/gbi.12539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 11/03/2022] [Accepted: 12/03/2022] [Indexed: 06/17/2023]
Abstract
Deep-sea hydrothermal systems provide ideal conditions for prebiotic reactions and ancient metabolic pathways and, therefore, might have played a pivotal role in the emergence of life. To understand this role better, it is paramount to examine fundamental interactions between hydrothermal processes, non-living matter, and microbial life in deep time. However, the distribution and diversity of microbial communities in ancient deep-sea hydrothermal systems are still poorly constrained, so evolutionary, and ecological relationships remain unclear. One important reason is an insufficient understanding of the formation of diagnostic microbial biosignatures in such settings and their preservation through geological time. This contribution centers around microbial biosignatures in Precambrian deep-sea hydrothermal sulfide deposits. Intending to provide a valuable resource for scientists from across the natural sciences whose research is concerned with the origins of life, we first introduce different types of biosignatures that can be preserved over geological timescales (rock fabrics and textures, microfossils, mineral precipitates, carbonaceous matter, trace metal, and isotope geochemical signatures). We then review selected reports of biosignatures from Precambrian deep-sea hydrothermal sulfide deposits and discuss their geobiological significance. Our survey highlights that Precambrian hydrothermal sulfide deposits potentially encode valuable information on environmental conditions, the presence and nature of microbial life, and the complex interactions between fluids, micro-organisms, and minerals. It further emphasizes that the geobiological interpretation of these records is challenging and requires the concerted application of analytical and experimental methods from various fields, including geology, mineralogy, geochemistry, and microbiology. Well-orchestrated multidisciplinary studies allow us to understand the formation and preservation of microbial biosignatures in deep-sea hydrothermal sulfide systems and thus help unravel the fundamental geobiology of ancient settings. This, in turn, is critical for reconstructing life's emergence and early evolution on Earth and the search for life elsewhere in the universe.
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Affiliation(s)
- Eric Alexander Runge
- Sedimentology and Organic Geochemistry, Department of Geosciences, Tübingen University, Tübingen, Germany
| | - Muammar Mansor
- Geomicrobiology, Department of Geosciences, Tübingen University, Tübingen, Germany
| | - Andreas Kappler
- Geomicrobiology, Department of Geosciences, Tübingen University, Tübingen, Germany
- Cluster of Excellence EXC 2124, Controlling Microbes to Fight Infection, Tübingen, Germany
| | - Jan-Peter Duda
- Sedimentology and Organic Geochemistry, Department of Geosciences, Tübingen University, Tübingen, Germany
- Geobiology, Geoscience Center, Göttingen University, Göttingen, Germany
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2
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Criado-Reyes J, Otálora F, Canals À, Verdugo-Escamilla C, García-Ruiz JM. Mechanisms shaping the gypsum stromatolite-like structures in the Salar de Llamara (Atacama Desert, Chile). Sci Rep 2023; 13:678. [PMID: 36635429 PMCID: PMC9837060 DOI: 10.1038/s41598-023-27666-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Accepted: 01/05/2023] [Indexed: 01/13/2023] Open
Abstract
The explanation of the origin of microbialites and specifically stromatolitic structures is a problem of high relevance for decoding past sedimentary environments and deciphering the biogenicity of the oldest plausible remnants of life. We have investigated the morphogenesis of gypsum stromatolite-like structures currently growing in shallow ponds (puquíos) in the Salar de Llamara (Atacama Desert, Northern Chile). The crystal size, aspect ratio, and orientation distributions of gypsum crystals within the structures have been quantified and show indications for episodic nucleation and competitive growth of millimetric to centimetric selenite crystals into a radial, branched, and loosely cemented aggregate. The morphogenetical process is explained by the existence of a stable vertical salinity gradient in the ponds. Due to the non-linear dependency of gypsum solubility as a function of sodium chloride concentration, the salinity gradient produces undersaturated solutions, which dissolve gypsum crystals. This dissolution happens at a certain depth, narrowing the lower part of the structures, and producing their stromatolite-like morphology. We have tested this novel mechanism experimentally, simulating the effective dissolution of gypsum crystals in stratified ponds, thus providing a purely abiotic mechanism for these stromatolite-like structures.
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Affiliation(s)
- Joaquín Criado-Reyes
- grid.466807.bLaboratorio de Estudios Cristalográficos, IACT, UGR-CSIC, Av. Palmeras 4, 18100 Armilla, Granada Spain
| | - Fermín Otálora
- grid.466807.bLaboratorio de Estudios Cristalográficos, IACT, UGR-CSIC, Av. Palmeras 4, 18100 Armilla, Granada Spain
| | - Àngels Canals
- grid.5841.80000 0004 1937 0247Departamento de Mineralogía, Petrología y Geología Aplicada, Facultad de Ciencias de La Tierra, Universidad de Barcelona, C/Martí i Franques s/n, 08028 Barcelona, Spain
| | - Cristóbal Verdugo-Escamilla
- grid.466807.bLaboratorio de Estudios Cristalográficos, IACT, UGR-CSIC, Av. Palmeras 4, 18100 Armilla, Granada Spain
| | - Juan-Manuel García-Ruiz
- Laboratorio de Estudios Cristalográficos, IACT, UGR-CSIC, Av. Palmeras 4, 18100, Armilla, Granada, Spain.
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3
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Mineral Paragenesis Precipitating in Salt Flat Pools of Continental Environments Replicated in Microbial Mat Microcosms without Evaporation. MINERALS 2022. [DOI: 10.3390/min12050646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Mineral precipitation can be observed in natural environments, such as lagoons, rivers, springs, and soils. The primary precipitation process has long been believed to be abiotic due to evaporation, leading to phase supersaturation. However, biotic interactions of microbial metabolism, organic compounds, and dissolved ions leading to mineral precipitation has been shown in laboratory studies using single-organism culture. The increase in pH inducing calcium carbonate precipitation due to oxygenic photosynthesis by Cyanobacteria and the release of ions due to organic matter decomposition by Firmicutes-inducing magnesium carbonate precipitation are recognized examples. As microbes do not live as pure cultures in natural environments but form complex communities, such pure culture lab studies do not reflect natural conditions. In this study, we grew natural complex microbial communities in microcosm conditions using filtered brine as water column and two types of natural gypsum substrates, and we replenished incubations to avoid evaporation. We monitored microbial communities through optical microscopy and analyzed mineral paragenesis in association with and without microbes, using different analytical techniques, such X-ray diffraction, and optical and field emission scanning electron microscopies. To detect changes throughout the experiment, small amounts of water column brine were extracted for physicochemial determinations. We were able to detect mineral paragenesis, avoiding evaporation, including major phases of chemical sedimentary rocks, such as gypsum, calcium carbonate, and some silicates in association to microbes. In addition, we evidenced that the use of natural substrates positively impacts growth of microbial communities, promoting the development of more biomass. This study can be seen as the first attempt and proof of concept of differentiating biotic and abiotic participation in evaporitic deposits, as they can form mineral paragenesis without evaporation. Future studies with microcosm experiments using microbial mats will be needed to establish mineral precipitation induced by micro-organisms and their extracellular polymeric substances (EPS), specifically to replicate mineral paragenesis sedimented from natural brines.
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4
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McMahon S, Ivarsson M, Wacey D, Saunders M, Belivanova V, Muirhead D, Knoll P, Steinbock O, Frost DA. Dubiofossils from a Mars-analogue subsurface palaeoenvironment: The limits of biogenicity criteria. GEOBIOLOGY 2021; 19:473-488. [PMID: 33951268 DOI: 10.1111/gbi.12445] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 03/12/2021] [Accepted: 03/30/2021] [Indexed: 06/12/2023]
Abstract
The search for a fossil record of Earth's deep biosphere, partly motivated by potential analogies with subsurface habitats on Mars, has uncovered numerous assemblages of inorganic microfilaments and tubules inside ancient pores and fractures. Although these enigmatic objects are morphologically similar to mineralized microorganisms (and some contain organic carbon), they also resemble some abiotic structures. Palaeobiologists have responded to this ambiguity by evaluating problematic filaments against checklists of "biogenicity criteria". Here, we describe material that tests the limits of this approach. We sampled Jurassic calcite veins formed through subseafloor serpentinization, a water-rock reaction that can fuel the deep biosphere and is known to have occurred widely on Mars. At two localities ~4 km apart, veins contained curving, branched microfilaments composed of Mg-silicate and Fe-oxide minerals. Using a wide range of analytical techniques including synchrotron X-ray microtomography and scanning transmission electron microscopy, we show that these features meet many published criteria for biogenicity and are comparable to fossilized cryptoendolithic fungi or bacteria. However, we argue that abiotic processes driven by serpentinization could account for the same set of lifelike features, and report a chemical garden experiment that supports this view. These filaments are, therefore, most objectively described as dubiofossils, a designation we here defend from criticism and recommend over alternative approaches, but which nevertheless signifies an impasse. Similar impasses can be anticipated in the future exploration of subsurface palaeo-habitats on Earth and Mars. To avoid them, further studies are required in biomimetic geochemical self-organization, microbial taphonomy and micro-analytical techniques, with a focus on subsurface habitats.
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Affiliation(s)
- Sean McMahon
- UK Centre for Astrobiology, School of Physics and Astronomy, University of Edinburgh, Edinburgh, UK
- School of Geosciences, Grant Institute, University of Edinburgh, Edinburgh, UK
| | - Magnus Ivarsson
- Department of Paleobiology, Swedish Museum of Natural History, Stockholm, Sweden
| | - David Wacey
- Centre for Microscopy Characterisation and Analysis, The University of Western Australia, Perth, WA, Australia
| | - Martin Saunders
- Centre for Microscopy Characterisation and Analysis, The University of Western Australia, Perth, WA, Australia
| | - Veneta Belivanova
- Department of Paleobiology, Swedish Museum of Natural History, Stockholm, Sweden
| | - David Muirhead
- School of Geosciences, King's College, University of Aberdeen, Aberdeen, UK
| | - Pamela Knoll
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL, USA
| | - Oliver Steinbock
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL, USA
| | - Daniel A Frost
- Department of Earth & Planetary Science, University of California, Berkeley, CA, USA
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5
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Rouillard J, van Zuilen M, Pisapia C, Garcia-Ruiz JM. An Alternative Approach for Assessing Biogenicity. ASTROBIOLOGY 2021; 21:151-164. [PMID: 33544651 PMCID: PMC7876362 DOI: 10.1089/ast.2020.2282] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2020] [Accepted: 09/07/2020] [Indexed: 05/27/2023]
Abstract
The search for signs of life in the ancient rock record, extreme terrestrial environments, and other planetary bodies requires a well-established, universal, and unambiguous test of biogenicity. This is notably true for cellular remnants of microbial life, since their relatively simple morphologies resemble various abiogenic microstructures that occur in nature. Although lists of qualitative biogenicity criteria have been devised, debates regarding the biogenicity of many ancient microfossils persist to this day. We propose here an alternative quantitative approach for assessing the biogenicity of putative microfossils. In this theoretical approach, different hypotheses-involving biology or not and depending on the geologic setting-are put forward to explain the observed objects. These hypotheses correspond to specific types of microstructures/systems. Using test samples, the morphology and/or chemistry of these systems are then characterized at the scale of populations. Morphologic parameters include, for example, circularity, aspect ratio, and solidity, while chemical parameters could include elementary ratios (e.g., N/C ratio), isotopic enrichments (e.g., δ13C), or chirality (e.g., molar proportion of stereoisomers), among others. Statistic trends distinguishing the different systems are then searched for empirically. The trends found are translated into "decision spaces" where the different systems are quantitatively discriminated and where the potential microfossil population can be located as a single point. This approach, which is formulated here on a theoretical level, will solve several problems associated with the classical qualitative criteria of biogenicity. Most importantly, it could be applied to reveal the existence of cellular life on other planets, for which characteristics of morphology and chemical composition are difficult to predict.
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Affiliation(s)
- Joti Rouillard
- Laboratario de Estudios Cristalograficos, Instituto Andaluz de Ciencias de la Tierra, CSIC—Universidad de Granada, Armilla, Spain
| | - Mark van Zuilen
- Institut de Physique du Globe de Paris, Université de Paris, CNRS UMR 7154, Paris, France
| | - Céline Pisapia
- Institut de Physique du Globe de Paris, Université de Paris, CNRS UMR 7154, Paris, France
| | - Juan-Manuel Garcia-Ruiz
- Laboratario de Estudios Cristalograficos, Instituto Andaluz de Ciencias de la Tierra, CSIC—Universidad de Granada, Armilla, Spain
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6
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Murphy RJ, Van Kranendonk MJ, Baumgartner R, Ryan C. Biogenicity of Spicular Geyserite from Te Kopia, New Zealand: Integrated Petrography, High-Resolution Hyperspectral and Elemental Analysis. ASTROBIOLOGY 2021; 21:115-135. [PMID: 33085533 DOI: 10.1089/ast.2019.2067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Hyperspectral and micro X-ray fluorescence (μXRF) imagery were used to derive maps of mineralogy and elemental chemistry from a sample of a siliceous hot spring deposit, or sinter, collected from a landslide breccia deposit at the base of the Paeroa fault, which bounds the eastern Taupo Rift at Te Kopia, Taupo Volcanic Zone, New Zealand. The sample is of a known biogenic sinter layer from a paleo-vent area of a recently extinct alkali chloride hot spring. The aim of the study was to distinguish it from other horizons derived from nonbiogenic sources, which is of relevance to early and extraterrestrial life research, specifically to help assess the potential reliability of morphology as an indicator of biology in the geological record. In particular, the distribution of opal, a common mineral in hot springs deposits that is known to preserve microbial features, and the relative abundances of Al-OH clay and water (OH and H2O) were mapped from hyperspectral imagery and element distributions defined by μXRF element mapping. Layers within the sinter sample composed of spicular geyserite-a type of micro-columnar stromatolite-showed contrasting mineralogy and water content in comparison with interspicular clastic sediment. Whereas clay was found to be concentrated in the interspicular sediment, high water contents characterized the spicules. μXRF imagery also showed differences in the composition of the two components of the spicule-bearing layers, with interspicular sediment being enriched in K, Ti, Fe, and Rb relative to the spicules, which are enriched in Ga. The contrasting nature of the mapped components highlights the detailed upward-branching nature of the spicules, identical to those found in living microstromatolites. These discriminants show that the spicular component can be discerned from the geological background through hyperspectral and μXRF mapping and used to define morphological features that may survive burial diagenesis and metamorphism as a biosignature in deep time rocks.
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Affiliation(s)
- Richard J Murphy
- Australian Centre for Field Robotics, Department of Aerospace, Mechanical & Mechatronic Engineering, The University of Sydney, Sydney, Australia
| | - Martin J Van Kranendonk
- Australian Centre for Astrobiology, and School of Biological and Earth and Environmental Sciences, University of New South Wales, Sydney, Australia
| | - Raphael Baumgartner
- Australian Centre for Astrobiology, and School of Biological and Earth and Environmental Sciences, University of New South Wales, Sydney, Australia
| | - Chris Ryan
- Commonwealth Scientific and Industrial Research Organisation (CSIRO), Canberra, Australia
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7
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Corenblit D, Darrozes J, Julien F, Otto T, Roussel E, Steiger J, Viles H. The Search for a Signature of Life on Mars: A Biogeomorphological Approach. ASTROBIOLOGY 2019; 19:1279-1291. [PMID: 31584307 DOI: 10.1089/ast.2018.1969] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Geological evidence shows that life on Earth evolved in line with major concomitant changes in Earth surface processes and landforms. Biogeomorphological characteristics, especially those involving microorganisms, are potentially important facets of biosignatures on Mars and are generating increasing interest in astrobiology. Using Earth as an analog provides reasons to suspect that past or present life on Mars could have resulted in recognizable biogenic landforms. Here, we discuss the potential for, and limitations of, a biogeomorphological approach to identifying the subsets of landforms that are modulated or created through biological processes and thus present signatures of life on Mars. Subsets especially involving microorganisms that are potentially important facets of biosignatures on Mars are proposed: (i) weathering features, biocrusts, patinas, and varnishes; (ii) microbialites and microbially induced sedimentary structures (MISS); (iii) bioaccumulations of skeletal remains; (iv) degassing landforms; (v) cryoconites; (vi) self-organized patterns; (vii) unclassified non-analog landforms. We propose a biogeomorphological frequency histogram approach to identify anomalies/modulations in landform properties. Such detection of anomalies/modulations will help track a biotic origin and lead to the development of an integrative multiproxy and multiscale approach combining morphological, structural, textural, and geochemical expertise. This perspective can help guide the choice of investigation sites for future missions and the types and scales of observations to be made by orbiters and rovers.
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Affiliation(s)
- Dov Corenblit
- Université Clermont Auvergne, CNRS, GEOLAB - F-63000 Clermont-Ferrand, France
| | - José Darrozes
- Université Paul Sabatier, CNRS/IRD, GET - F-31062 Toulouse, France
| | - Frédéric Julien
- CNRS, ECOLAB, Université Paul Sabatier, CNRS, INPT, UPS, F-31062 Toulouse, France
| | - Thierry Otto
- CNRS, ECOLAB, Université Paul Sabatier, CNRS, INPT, UPS, F-31062 Toulouse, France
| | - Erwan Roussel
- Université Clermont Auvergne, CNRS, GEOLAB - F-63000 Clermont-Ferrand, France
| | - Johannes Steiger
- Université Clermont Auvergne, CNRS, GEOLAB - F-63000 Clermont-Ferrand, France
| | - Heather Viles
- School of Geography and the Environment, University of Oxford, Oxford, United Kingdom
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8
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Onstott T, Ehlmann B, Sapers H, Coleman M, Ivarsson M, Marlow J, Neubeck A, Niles P. Paleo-Rock-Hosted Life on Earth and the Search on Mars: A Review and Strategy for Exploration. ASTROBIOLOGY 2019; 19:1230-1262. [PMID: 31237436 PMCID: PMC6786346 DOI: 10.1089/ast.2018.1960] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2018] [Accepted: 04/25/2019] [Indexed: 05/19/2023]
Abstract
Here we review published studies on the abundance and diversity of terrestrial rock-hosted life, the environments it inhabits, the evolution of its metabolisms, and its fossil biomarkers to provide guidance in the search for life on Mars. Key findings are (1) much terrestrial deep subsurface metabolic activity relies on abiotic energy-yielding fluxes and in situ abiotic and biotic recycling of metabolic waste products rather than on buried organic products of photosynthesis; (2) subsurface microbial cell concentrations are highest at interfaces with pronounced chemical redox gradients or permeability variations and do not correlate with bulk host rock organic carbon; (3) metabolic pathways for chemolithoautotrophic microorganisms evolved earlier in Earth's history than those of surface-dwelling phototrophic microorganisms; (4) the emergence of the former occurred at a time when Mars was habitable, whereas the emergence of the latter occurred at a time when the martian surface was not continually habitable; (5) the terrestrial rock record has biomarkers of subsurface life at least back hundreds of millions of years and likely to 3.45 Ga with several examples of excellent preservation in rock types that are quite different from those preserving the photosphere-supported biosphere. These findings suggest that rock-hosted life would have been more likely to emerge and be preserved in a martian context. Consequently, we outline a Mars exploration strategy that targets subsurface life and scales spatially, focusing initially on identifying rocks with evidence for groundwater flow and low-temperature mineralization, then identifying redox and permeability interfaces preserved within rock outcrops, and finally focusing on finding minerals associated with redox reactions and associated traces of carbon and diagnostic chemical and isotopic biosignatures. Using this strategy on Earth yields ancient rock-hosted life, preserved in the fossil record and confirmable via a suite of morphologic, organic, mineralogical, and isotopic fingerprints at micrometer scale. We expect an emphasis on rock-hosted life and this scale-dependent strategy to be crucial in the search for life on Mars.
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Affiliation(s)
- T.C. Onstott
- Department of Geosciences, Princeton University, Princeton, New Jersey, USA
- Address correspondence to: T.C. Onstott, Department of Geosciences, Princeton University,, Princeton, NJ 008544
| | - B.L. Ehlmann
- Division of Geological & Planetary Sciences, California Institute of Technology, Pasadena, California, USA
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
- B.L. Ehlmann, Division of Geological & Planetary Sciences, California Institute of Technology, Pasadena, CA 91125
| | - H. Sapers
- Division of Geological & Planetary Sciences, California Institute of Technology, Pasadena, California, USA
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
- Department of Earth Sciences, University of Southern California, Los Angeles, California, USA
| | - M. Coleman
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
- NASA Astrobiology Institute, Pasadena, California, USA
| | - M. Ivarsson
- Department of Biology, University of Southern Denmark, Odense, Denmark
| | - J.J. Marlow
- Department of Organismic & Evolutionary Biology, Harvard University, Cambridge, Massachusetts, USA
| | - A. Neubeck
- Department of Earth Sciences, Uppsala University, Uppsala, Sweden
| | - P. Niles
- Astromaterials Research and Exploration Science Division, NASA Johnson Space Center, Houston, Texas, USA
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9
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Chan MA, Hinman NW, Potter-McIntyre SL, Schubert KE, Gillams RJ, Awramik SM, Boston PJ, Bower DM, Des Marais DJ, Farmer JD, Jia TZ, King PL, Hazen RM, Léveillé RJ, Papineau D, Rempfert KR, Sánchez-Román M, Spear JR, Southam G, Stern JC, Cleaves HJ. Deciphering Biosignatures in Planetary Contexts. ASTROBIOLOGY 2019; 19:1075-1102. [PMID: 31335163 PMCID: PMC6708275 DOI: 10.1089/ast.2018.1903] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 03/10/2019] [Indexed: 05/05/2023]
Abstract
Microbial life permeates Earth's critical zone and has likely inhabited nearly all our planet's surface and near subsurface since before the beginning of the sedimentary rock record. Given the vast time that Earth has been teeming with life, do astrobiologists truly understand what geological features untouched by biological processes would look like? In the search for extraterrestrial life in the Universe, it is critical to determine what constitutes a biosignature across multiple scales, and how this compares with "abiosignatures" formed by nonliving processes. Developing standards for abiotic and biotic characteristics would provide quantitative metrics for comparison across different data types and observational time frames. The evidence for life detection falls into three categories of biosignatures: (1) substances, such as elemental abundances, isotopes, molecules, allotropes, enantiomers, minerals, and their associated properties; (2) objects that are physical features such as mats, fossils including trace-fossils and microbialites (stromatolites), and concretions; and (3) patterns, such as physical three-dimensional or conceptual n-dimensional relationships of physical or chemical phenomena, including patterns of intermolecular abundances of organic homologues, and patterns of stable isotopic abundances between and within compounds. Five key challenges that warrant future exploration by the astrobiology community include the following: (1) examining phenomena at the "right" spatial scales because biosignatures may elude us if not examined with the appropriate instrumentation or modeling approach at that specific scale; (2) identifying the precise context across multiple spatial and temporal scales to understand how tangible biosignatures may or may not be preserved; (3) increasing capability to mine big data sets to reveal relationships, for example, how Earth's mineral diversity may have evolved in conjunction with life; (4) leveraging cyberinfrastructure for data management of biosignature types, characteristics, and classifications; and (5) using three-dimensional to n-D representations of biotic and abiotic models overlain on multiple overlapping spatial and temporal relationships to provide new insights.
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Affiliation(s)
- Marjorie A. Chan
- Department of Geology & Geophysics, University of Utah, Salt Lake City, Utah
| | - Nancy W. Hinman
- Department of Geosciences, University of Montana, Missoula, Montana
| | | | - Keith E. Schubert
- Department of Electrical and Computer Engineering, Baylor University, Waco, Texas
| | - Richard J. Gillams
- Earth-Life Science Institute, Tokyo Institute of Technology, Tokyo, Japan
- Electronics and Computer Science, Institute for Life Sciences, University of Southampton, Southampton, United Kingdom
| | - Stanley M. Awramik
- Department of Earth Science, University of California, Santa Barbara, Santa Barbara, California
| | - Penelope J. Boston
- NASA Astrobiology Institute, NASA Ames Research Center, Moffett Field, California
| | - Dina M. Bower
- Department of Astronomy, University of Maryland College Park (CRESST), College Park, Maryland
- NASA Goddard Space Flight Center, Greenbelt, Maryland
| | | | - Jack D. Farmer
- School of Earth and Space Exploration, Arizona State University, Tempe, Arizona
| | - Tony Z. Jia
- Earth-Life Science Institute, Tokyo Institute of Technology, Tokyo, Japan
| | - Penelope L. King
- Research School of Earth Sciences, The Australian National University, Canberra, Australia
| | - Robert M. Hazen
- Geophysical Laboratory, Carnegie Institution for Science, Washington, District of Columbia
| | - Richard J. Léveillé
- Department of Earth and Planetary Sciences, McGill University, Montreal, Canada
- Geosciences Department, John Abbott College, Sainte-Anne-de-Bellevue, Canada
| | - Dominic Papineau
- London Centre for Nanotechnology, University College London, London, United Kingdom
- Department of Earth Sciences, University College London, London, United Kingdom
- Centre for Planetary Sciences, University College London, London, United Kingdom
- BioGeology and Environmental Geology State Key Laboratory, School of Earth Sciences, China University of Geosciences, Wuhan, China
| | - Kaitlin R. Rempfert
- Department of Geological Sciences, University of Colorado Boulder, Boulder, Colorado
| | - Mónica Sánchez-Román
- Earth Sciences Department, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - John R. Spear
- Department of Civil and Environmental Engineering, Colorado School of Mines, Golden, Colorado
| | - Gordon Southam
- School of Earth and Environmental Sciences, The University of Queensland, St. Lucia, Queensland, Australia
| | | | - Henderson James Cleaves
- Earth-Life Science Institute, Tokyo Institute of Technology, Tokyo, Japan
- Program in Interdisciplinary Studies, Institute for Advanced Study, Princeton, New Jersey
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10
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Javaux EJ. Challenges in evidencing the earliest traces of life. Nature 2019; 572:451-460. [PMID: 31435057 DOI: 10.1038/s41586-019-1436-4] [Citation(s) in RCA: 112] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Accepted: 06/21/2019] [Indexed: 11/09/2022]
Abstract
Earth has been habitable for 4.3 billion years, and the earliest rock record indicates the presence of a microbial biosphere by at least 3.4 billion years ago-and disputably earlier. Possible traces of life can be morphological or chemical but abiotic processes that mimic or alter them, or subsequent contamination, may challenge their interpretation. Advances in micro- and nanoscale analyses, as well as experimental approaches, are improving the characterization of these biosignatures and constraining abiotic processes, when combined with the geological context. Reassessing the evidence of early life is challenging, but essential and timely in the quest to understand the origin and evolution of life, both on Earth and beyond.
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Affiliation(s)
- Emmanuelle J Javaux
- Early Life Traces & Evolution-Astrobiology, UR Astrobiology, Department of Geology, University of Liège, Liège, Belgium.
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11
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Mechanistic Morphogenesis of Organo-Sedimentary Structures Growing Under Geochemically Stressed Conditions: Keystone to Proving the Biogenicity of Some Archaean Stromatolites? GEOSCIENCES 2019. [DOI: 10.3390/geosciences9080359] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Morphologically diverse organo-sedimentary structures (including microbial mats and stromatolites) provide a palaeobiological record through more than three billion years of Earth history. Since understanding much of the Archaean fossil record is contingent upon proving the biogenicity of such structures, mechanistic interpretations of well-preserved fossil microbialites can reinforce our understanding of their biogeochemistry and distinguish unambiguous biological characteristics in these structures, which represent some of the earliest records of life. Mechanistic morphogenetic understanding relies upon the analysis of geomicrobiological experiments. Herein, we report morphological-biogeochemical comparisons between micromorphologies observed in growth experiments using photosynthetic mats built by the cyanobacterium Coleofasciculus chthonoplastes (formerly Microcoleus) and green anoxygenic phototrophic Chloroflexus spp. (i.e., Coleofasciculus–Chloroflexus mats), and Precambrian organo-sedimentary structures, demonstrating parallels between them. In elevated ambient concentrations of Cu (toxic to Coleofasciculus), Coleofasciculus–Chloroflexus mats respond by forming centimetre-scale pinnacle-like structures (supra-lamina complexities) associated with large quantities of EPS at their surfaces. µPIXE mapping shows that Cu and other metals become concentrated within surficial sheath-EPS-Chloroflexus-rich layers, producing density-differential micromorphologies with distinct fabric orientations that are detectable using X-ray computed micro-tomography (X-ray µCT). Similar micromorphologies are also detectable in stromatolites from the 3.481 Ga Dresser Formation (Pilbara, Western Australia). The cause and response link between the presence of toxic elements (geochemical stress) and the development of multi-layered topographical complexities in organo-sedimentary structures may thus be considered an indicator of biogenicity, being an indisputably biological and predictable morphogenetic response reflecting, in this case, the differential responses of Coleofasciculus and Chloroflexus to Cu. Growth models for microbialite morphogenesis rely upon linking morphology to intrinsic (biological) and extrinsic (environmental) influences. Since the pinnacles of Coleofasciculus–Chloroflexus mats have an unambiguously biological origin linked to extrinsic geochemistry, we suggest that similar micromorphologies observed in ancient organo-sedimentary structures are indicative of biogenesis. An identical Coleofasciculus–Chloroflexus community subjected to salinity stress also produced supra-lamina complexities (tufts) but did not produce identifiable micromorphologies in three dimensions since salinity seems not to negatively impact either organism, and therefore cannot be used as a morphogenetic tool for the interpretation of density-homogeneous micro-tufted mats—for example, those of the 3.472 Ga Middle Marker horizon. Thus, although correlative microscopy is the keystone to confirming the biogenicity of certain Precambrian stromatolites, it remains crucial to separately interrogate each putative trace of ancient life, ideally using three-dimensional analyses, to determine, where possible, palaeoenvironmental influences on morphologies. Widespread volcanism and hydrothermal effusion into the early oceans likely concentrated toxic elements in early biomes. Morphological diversity in fossil microbialites could, therefore, reflect either (or both of) differential exposure to ambient fluids enriched in toxic elements and/or changing ecosystem structure and tolerance to elements through evolutionary time—for example, after incorporation into enzymes. Proof of biogenicity by deducing morphogenesis (i.e., a process preserved in the fossil record) overcomes many of the shortcomings inherent to the proof of biogenicity by descriptions of morphology alone.
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Living Dendrolitic Microbial Mats in Hamelin Pool, Shark Bay, Western Australia. GEOSCIENCES 2018. [DOI: 10.3390/geosciences8060212] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Gérard E, De Goeyse S, Hugoni M, Agogué H, Richard L, Milesi V, Guyot F, Lecourt L, Borensztajn S, Joseph MB, Leclerc T, Sarazin G, Jézéquel D, Leboulanger C, Ader M. Key Role of Alphaproteobacteria and Cyanobacteria in the Formation of Stromatolites of Lake Dziani Dzaha (Mayotte, Western Indian Ocean). Front Microbiol 2018; 9:796. [PMID: 29872424 PMCID: PMC5972316 DOI: 10.3389/fmicb.2018.00796] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2018] [Accepted: 04/09/2018] [Indexed: 01/09/2023] Open
Abstract
Lake Dziani Dzaha is a thalassohaline tropical crater lake located on the "Petite Terre" Island of Mayotte (Comoros archipelago, Western Indian Ocean). Stromatolites are actively growing in the shallow waters of the lake shores. These stromatolites are mainly composed of aragonite with lesser proportions of hydromagnesite, calcite, dolomite, and phyllosilicates. They are morphologically and texturally diverse ranging from tabular covered by a cauliflower-like crust to columnar ones with a smooth surface. High-throughput sequencing of bacterial and archaeal 16S rRNA genes combined with confocal laser scanning microscopy (CLSM) analysis revealed that the microbial composition of the mats associated with the stromatolites was clearly distinct from that of the Arthrospira-dominated lake water. Unicellular-colonial Cyanobacteria belonging to the Xenococcus genus of the Pleurocapsales order were detected in the cauliflower crust mats, whereas filamentous Cyanobacteria belonging to the Leptolyngbya genus were found in the smooth surface mats. Observations using CLSM, scanning electron microscopy (SEM) and Raman spectroscopy indicated that the cauliflower texture consists of laminations of aragonite, magnesium-silicate phase and hydromagnesite. The associated microbial mat, as confirmed by laser microdissection and whole-genome amplification (WGA), is composed of Pleurocapsales coated by abundant filamentous and coccoid Alphaproteobacteria. These phototrophic Alphaproteobacteria promote the precipitation of aragonite in which they become incrusted. In contrast, the Pleurocapsales are not calcifying but instead accumulate silicon and magnesium in their sheaths, which may be responsible for the formation of the Mg-silicate phase found in the cauliflower crust. We therefore propose that Pleurocapsales and Alphaproteobacteria are involved in the formation of two distinct mineral phases present in the cauliflower texture: Mg-silicate and aragonite, respectively. These results point out the role of phototrophic Alphaproteobacteria in the formation of stromatolites, which may open new perspective for the analysis of the fossil record.
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Affiliation(s)
- Emmanuelle Gérard
- UMR CNRS 7154 Institut de Physique du Globe de Paris, Sorbonne Paris Cité, Université Paris Diderot, Centre National de la Recherche Scientifique, Paris, France
| | - Siham De Goeyse
- UMR CNRS 7154 Institut de Physique du Globe de Paris, Sorbonne Paris Cité, Université Paris Diderot, Centre National de la Recherche Scientifique, Paris, France
| | - Mylène Hugoni
- Université Lyon 1, UMR CNRS 5557 / INRA 1418, Ecologie Microbienne, Villeurbanne, France
| | - Hélène Agogué
- UMR 7266 CNRS-Université de la Rochelle, LIttoral ENvironnement Et Sociétés, La Rochelle, France
| | - Laurent Richard
- School of Mining and Geosciences, Nazarbayev University, Astana, Kazakhstan
| | - Vincent Milesi
- UMR CNRS 7154 Institut de Physique du Globe de Paris, Sorbonne Paris Cité, Université Paris Diderot, Centre National de la Recherche Scientifique, Paris, France
| | - François Guyot
- Museum National d’Histoire Naturelle, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, UMR 7590 CNRS Sorbonne Universités, Université Pierre et Marie Curie, Institut de Recherche pour le Développement UMR 206, Paris, France
| | - Léna Lecourt
- UMR CNRS 7154 Institut de Physique du Globe de Paris, Sorbonne Paris Cité, Université Paris Diderot, Centre National de la Recherche Scientifique, Paris, France
| | - Stephan Borensztajn
- UMR CNRS 7154 Institut de Physique du Globe de Paris, Sorbonne Paris Cité, Université Paris Diderot, Centre National de la Recherche Scientifique, Paris, France
| | - Marie-Béatrice Joseph
- UMR CNRS 7154 Institut de Physique du Globe de Paris, Sorbonne Paris Cité, Université Paris Diderot, Centre National de la Recherche Scientifique, Paris, France
| | - Thomas Leclerc
- UMR CNRS 7154 Institut de Physique du Globe de Paris, Sorbonne Paris Cité, Université Paris Diderot, Centre National de la Recherche Scientifique, Paris, France
| | - Gérard Sarazin
- UMR CNRS 7154 Institut de Physique du Globe de Paris, Sorbonne Paris Cité, Université Paris Diderot, Centre National de la Recherche Scientifique, Paris, France
| | - Didier Jézéquel
- UMR CNRS 7154 Institut de Physique du Globe de Paris, Sorbonne Paris Cité, Université Paris Diderot, Centre National de la Recherche Scientifique, Paris, France
| | | | - Magali Ader
- UMR CNRS 7154 Institut de Physique du Globe de Paris, Sorbonne Paris Cité, Université Paris Diderot, Centre National de la Recherche Scientifique, Paris, France
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McMahon S, Bosak T, Grotzinger JP, Milliken RE, Summons RE, Daye M, Newman SA, Fraeman A, Williford KH, Briggs DEG. A Field Guide to Finding Fossils on Mars. JOURNAL OF GEOPHYSICAL RESEARCH. PLANETS 2018; 123:1012-1040. [PMID: 30034979 PMCID: PMC6049883 DOI: 10.1029/2017je005478] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Revised: 03/28/2018] [Accepted: 04/23/2018] [Indexed: 05/05/2023]
Abstract
The Martian surface is cold, dry, exposed to biologically harmful radiation and apparently barren today. Nevertheless, there is clear geological evidence for warmer, wetter intervals in the past that could have supported life at or near the surface. This evidence has motivated National Aeronautics and Space Administration and European Space Agency to prioritize the search for any remains or traces of organisms from early Mars in forthcoming missions. Informed by (1) stratigraphic, mineralogical and geochemical data collected by previous and current missions, (2) Earth's fossil record, and (3) experimental studies of organic decay and preservation, we here consider whether, how, and where fossils and isotopic biosignatures could have been preserved in the depositional environments and mineralizing media thought to have been present in habitable settings on early Mars. We conclude that Noachian-Hesperian Fe-bearing clay-rich fluvio-lacustrine siliciclastic deposits, especially where enriched in silica, currently represent the most promising and best understood astropaleontological targets. Siliceous sinters would also be an excellent target, but their presence on Mars awaits confirmation. More work is needed to improve our understanding of fossil preservation in the context of other environments specific to Mars, particularly within evaporative salts and pore/fracture-filling subsurface minerals.
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Affiliation(s)
- S. McMahon
- Department of Geology and GeophysicsYale UniversityNew HavenCTUSA
- UK Centre for Astrobiology, School of Physics and AstronomyUniversity of EdinburghEdinburghUK
| | - T. Bosak
- Department of Earth, Atmospheric and Planetary SciencesMassachusetts Institute of TechnologyCambridgeMAUSA
| | - J. P. Grotzinger
- Division of Geological and Planetary SciencesCalifornia Institute of TechnologyPasadenaCAUSA
| | - R. E. Milliken
- Department of Earth, Environmental and Planetary SciencesBrown UniversityProvidenceRIUSA
| | - R. E. Summons
- Department of Earth, Atmospheric and Planetary SciencesMassachusetts Institute of TechnologyCambridgeMAUSA
| | - M. Daye
- Department of Earth, Atmospheric and Planetary SciencesMassachusetts Institute of TechnologyCambridgeMAUSA
| | - S. A. Newman
- Department of Earth, Atmospheric and Planetary SciencesMassachusetts Institute of TechnologyCambridgeMAUSA
| | - A. Fraeman
- Jet Propulsion LaboratoryCalifornia Institute of TechnologyPasadenaCAUSA
| | - K. H. Williford
- Jet Propulsion LaboratoryCalifornia Institute of TechnologyPasadenaCAUSA
| | - D. E. G. Briggs
- Department of Geology and GeophysicsYale UniversityNew HavenCTUSA
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Rouillard J, García‐Ruiz J, Gong J, van Zuilen MA. A morphogram for silica-witherite biomorphs and its application to microfossil identification in the early earth rock record. GEOBIOLOGY 2018; 16:279-296. [PMID: 29485245 PMCID: PMC5947568 DOI: 10.1111/gbi.12278] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 01/11/2018] [Indexed: 06/01/2023]
Abstract
Archean hydrothermal environments formed a likely site for the origin and early evolution of life. These are also the settings, however, were complex abiologic structures can form. Low-temperature serpentinization of ultramafic crust can generate alkaline, silica-saturated fluids in which carbonate-silica crystalline aggregates with life-like morphologies can self-assemble. These "biomorphs" could have adsorbed hydrocarbons from Fischer-Tropsch type synthesis processes, leading to metamorphosed structures that resemble carbonaceous microfossils. Although this abiogenic process has been extensively cited in the literature and has generated important controversy, so far only one specific biomorph type with a filamentous shape has been discussed for the interpretation of Archean microfossils. It is therefore critical to precisely determine the full distribution in morphology and size of these biomorphs, and to study the range of plausible geochemical conditions under which these microstructures can form. Here, a set of witherite-silica biomorph synthesis experiments in silica-saturated solutions is presented, for a range of pH values (from 9 to 11.5) and barium ion concentrations (from 0.6 to 40 mmol/L BaCl2 ). Under these varying conditions, a wide range of life-like structures is found, from fractal dendrites to complex shapes with continuous curvature. The size, spatial concentration, and morphology of the biomorphs are strongly controlled by environmental parameters, among which pH is the most important. This potentially limits the diversity of environments in which the growth of biomorphs could have occurred on Early Earth. Given the variety of the observed biomorph morphologies, our results show that the morphology of an individual microstructure is a poor criterion for biogenicity. However, biomorphs may be distinguished from actual populations of cellular microfossils by their wide, unimodal size distribution. Biomorphs grown by diffusion in silica gel can be differentiated by their continuous gradient in size, spatial density, and morphology along the direction of diffusion.
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Affiliation(s)
- J. Rouillard
- Equipe GéomicrobiologieInstitut de Physique du Globe de Paris, Sorbonne Paris CitéUniversité Paris Diderot, UMR 7154, CNRSParisFrance
| | - J.‐M. García‐Ruiz
- Laboratorio de Estudios CristalográficosInstituto Andaluz de Ciencias de la TierraConsejo Superior de Investígacìones Cientificas–Universidad de GranadaGranadaSpain
| | - J. Gong
- Equipe GéomicrobiologieInstitut de Physique du Globe de Paris, Sorbonne Paris CitéUniversité Paris Diderot, UMR 7154, CNRSParisFrance
| | - M. A. van Zuilen
- Equipe GéomicrobiologieInstitut de Physique du Globe de Paris, Sorbonne Paris CitéUniversité Paris Diderot, UMR 7154, CNRSParisFrance
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Ruff SW, Farmer JD. Silica deposits on Mars with features resembling hot spring biosignatures at El Tatio in Chile. Nat Commun 2016; 7:13554. [PMID: 27853166 PMCID: PMC5473637 DOI: 10.1038/ncomms13554] [Citation(s) in RCA: 142] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Accepted: 10/13/2016] [Indexed: 11/09/2022] Open
Abstract
The Mars rover Spirit encountered outcrops and regolith composed of opaline silica (amorphous SiO2·nH2O) in an ancient volcanic hydrothermal setting in Gusev crater. An origin via either fumarole-related acid-sulfate leaching or precipitation from hot spring fluids was suggested previously. However, the potential significance of the characteristic nodular and mm-scale digitate opaline silica structures was not recognized. Here we report remarkably similar features within active hot spring/geyser discharge channels at El Tatio in northern Chile, where halite-encrusted silica yields infrared spectra that are the best match yet to spectra from Spirit. Furthermore, we show that the nodular and digitate silica structures at El Tatio that most closely resemble those on Mars include complex sedimentary structures produced by a combination of biotic and abiotic processes. Although fully abiotic processes are not ruled out for the Martian silica structures, they satisfy an a priori definition of potential biosignatures.
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Affiliation(s)
- Steven W Ruff
- School of Earth and Space Exploration, Arizona State University, Tempe, Arizona 85287-6305, USA
| | - Jack D Farmer
- School of Earth and Space Exploration, Arizona State University, Tempe, Arizona 85287-6305, USA
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Murphy RJ, Van Kranendonk MJ, Kelloway SJ, Wainwright IE. Complex patterns in fossilized stromatolites revealed by hyperspectral imaging (400-2496 nm). GEOBIOLOGY 2016; 14:419-439. [PMID: 27146219 DOI: 10.1111/gbi.12184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Accepted: 03/09/2016] [Indexed: 06/05/2023]
Abstract
Hyperspectral imaging (400-2496 nm) was used to quantitatively map surface textures and compositional variations in stromatolites to determine whether complexity of textures could be used as evidence to support biogenicity in the absence of preserved biomarkers. Four samples of 2.72-2.4 Ga stromatolites from a variety of settings, encompassing marine and lacustrine environments, were selected for hyperspectral imaging. Images of the sawn surfaces of samples were processed to identify reflectance and mineral absorption features and quantify their intensity (as an index of mineral abundance) using automated feature extraction. Amounts of ferrous iron were quantified using a ratio of reflectance at 1650 and 1299 nm. Visible near infrared imagery (400-970 nm) did not reveal additional textural patterns to those obtained from visual inspection. Shortwave infrared imagery (1000-2496 nm), however, revealed complex laminar and convoluted patterns, including a distinctive texture of sharp peaks and broad, low troughs in one sample, similar to living tufted microbial mats. Spectral analysis revealed another sample to be composed of dolomite. Two other samples were dominated by calcite or chlorite ± illite. Large variations in amounts of ferrous iron were found, but ferric iron was exclusively located in the oxidation crust. Hyperspectral imaging revealed large differences between parts of a sample of biogenic and non-biogenic origin. The former was characterized by calcite with varying amounts of ferrous iron, distributed in lenticular, convoluted patterns; the latter by Mg-Fe chlorite with large amounts of aluminium silicate, distributed as fine laminar layers. All minerals identified by hyperspectral imaging were confirmed by thin section petrography and XRD analyses. Spatial statistics generated from quantitative minerals maps showed different patterns between these different parts of the sample. Thus, hyperspectral imaging was shown to be a powerful tool for detecting structures in stromatolites that could be used, together with other lines of evidence, to support biogenicity.
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Affiliation(s)
- R J Murphy
- Australian Centre for Field Robotics, Department of Aerospace, Mechanical & Mechatronic Engineering, The University of Sydney, NSW, Australia
| | - M J Van Kranendonk
- Australian Centre for Astrobiology, and School of Biological and Earth and Environmental Sciences, University of New South Wales, Kensington, NSW, Australia
| | - S J Kelloway
- XRF Laboratory, Solid State and Elemental Analysis Unit, Mark Wainwright Analytical Centre, University of New South Wales, Kensington, NSW, Australia
| | - I E Wainwright
- XRF Laboratory, Solid State and Elemental Analysis Unit, Mark Wainwright Analytical Centre, University of New South Wales, Kensington, NSW, Australia
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Canfora L, Vendramin E, Vittori Antisari L, Lo Papa G, Dazzi C, Benedetti A, Iavazzo P, Adamo P, Jungblut AD, Pinzari F. Compartmentalization of gypsum and halite associated with cyanobacteria in saline soil crusts. FEMS Microbiol Ecol 2016; 92:fiw080. [PMID: 27090760 DOI: 10.1093/femsec/fiw080] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/08/2016] [Indexed: 11/14/2022] Open
Abstract
The interface between biological and geochemical components in the surface crust of a saline soil was investigated using X-ray diffraction, and variable pressure scanning electron microscopy in combination with energy dispersive X-ray spectrometry. Mineral compounds such as halite and gypsum were identified crystallized around filaments of cyanobacteria. A total of 92 genera were identified from the bacterial community based on 16S gene pyrosequencing analysis. The occurrence of the gypsum crystals, their shapes and compartmentalization suggested that they separated NaCl from the immediate microenvironment of the cyanobacteria, and that some cyanobacteria and communities of sulfur bacteria may had a physical control over the distinctive halite and gypsum structures produced. This suggests that cyanobacteria might directly or indirectly promote the formation of a protective envelope made of calcium and sulfur-based compounds.
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Affiliation(s)
- Loredana Canfora
- Consiglio per la Ricerca in Agricoltura e l'analisi dell'economia agraria, Centro di Ricerca per lo studio delle relazioni tra Pianta e Suolo, Rome, Italy
| | - Elisa Vendramin
- Consiglio per la Ricerca in Agricoltura e l'analisi dell'economia agraria, Centro di Ricerca per la Frutticoltura, Rome, Italy
| | | | - Giuseppe Lo Papa
- Dipartimento di Scienze Agrarie e Forestali, Università degli Studi di Palermo, Italy
| | - Carmelo Dazzi
- Dipartimento di Scienze Agrarie e Forestali, Università degli Studi di Palermo, Italy
| | - Anna Benedetti
- Consiglio per la Ricerca in Agricoltura e l'analisi dell'economia agraria, Centro di Ricerca per lo studio delle relazioni tra Pianta e Suolo, Rome, Italy
| | - Pietro Iavazzo
- Dipartimento di Agraria, Università di Napoli Federico II, Portici, Italy
| | - Paola Adamo
- Dipartimento di Agraria, Università di Napoli Federico II, Portici, Italy
| | - Anne D Jungblut
- Natural History Museum, Life Sciences Department, London, UK
| | - Flavia Pinzari
- Consiglio per la Ricerca in Agricoltura e l'analisi dell'economia agraria, Centro di Ricerca per lo studio delle relazioni tra Pianta e Suolo, Rome, Italy Natural History Museum, Life Sciences Department, London, UK
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Duda JP, Van Kranendonk MJ, Thiel V, Ionescu D, Strauss H, Schäfer N, Reitner J. A Rare Glimpse of Paleoarchean Life: Geobiology of an Exceptionally Preserved Microbial Mat Facies from the 3.4 Ga Strelley Pool Formation, Western Australia. PLoS One 2016; 11:e0147629. [PMID: 26807732 PMCID: PMC4726515 DOI: 10.1371/journal.pone.0147629] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Accepted: 01/06/2016] [Indexed: 11/19/2022] Open
Abstract
Paleoarchean rocks from the Pilbara Craton of Western Australia provide a variety of clues to the existence of early life on Earth, such as stromatolites, putative microfossils and geochemical signatures of microbial activity. However, some of these features have also been explained by non-biological processes. Further lines of evidence are therefore required to convincingly argue for the presence of microbial life. Here we describe a new type of microbial mat facies from the 3.4 Ga Strelley Pool Formation, which directly overlies well known stromatolitic carbonates from the same formation. This microbial mat facies consists of laminated, very fine-grained black cherts with discontinuous white quartz layers and lenses, and contains small domical stromatolites and wind-blown crescentic ripples. Light- and cathodoluminescence microscopy, Raman spectroscopy, and time of flight—secondary ion mass spectrometry (ToF-SIMS) reveal a spatial association of carbonates, organic material, and highly abundant framboidal pyrite within the black cherts. Nano secondary ion mass spectrometry (NanoSIMS) confirmed the presence of distinct spheroidal carbonate bodies up to several tens of μm that are surrounded by organic material and pyrite. These aggregates are interpreted as biogenic. Comparison with Phanerozoic analogues indicates that the facies represents microbial mats formed in a shallow marine environment. Carbonate precipitation and silicification by hydrothermal fluids occurred during sedimentation and earliest diagenesis. The deciphered environment, as well as the δ13C signature of bulk organic matter (-35.3‰), are in accord with the presence of photoautotrophs. At the same time, highly abundant framboidal pyrite exhibits a sulfur isotopic signature (δ34S = +3.05‰; Δ33S = 0.268‰; and Δ36S = -0.282‰) that is consistent with microbial sulfate reduction. Taken together, our results strongly support a microbial mat origin of the black chert facies, thus providing another line of evidence for life in the 3.4 Ga Strelley Pool Formation.
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Affiliation(s)
- Jan-Peter Duda
- Department of Geobiology, Geoscience Centre, Georg-August-University Göttingen, Goldschmidtstr. 3, 37077, Göttingen, Germany
- ‘Origin of Life’ Group, Göttingen Academy of Sciences and Humanities, Theaterstraße 7, 37073, Göttingen, Germany
- * E-mail:
| | - Martin J. Van Kranendonk
- Australian Centre for Astrobiology and School of Biological, Earth and Environmental Sciences, University of New South Wales, Kensington, NSW 2052, Australia
| | - Volker Thiel
- Department of Geobiology, Geoscience Centre, Georg-August-University Göttingen, Goldschmidtstr. 3, 37077, Göttingen, Germany
| | - Danny Ionescu
- Department of Experimental Limnology, Leibniz Institute for Freshwater Ecology and Inland Fisheries (IGB), Alte Fischerhütte 2, 16775, Stechlin, Germany
| | - Harald Strauss
- Institut für Geologie und Paläontologie, Westfälische Wilhelms-Universität Münster, Corrensstraße 24, 48149, Münster, Germany
| | - Nadine Schäfer
- Department of Geobiology, Geoscience Centre, Georg-August-University Göttingen, Goldschmidtstr. 3, 37077, Göttingen, Germany
| | - Joachim Reitner
- Department of Geobiology, Geoscience Centre, Georg-August-University Göttingen, Goldschmidtstr. 3, 37077, Göttingen, Germany
- ‘Origin of Life’ Group, Göttingen Academy of Sciences and Humanities, Theaterstraße 7, 37073, Göttingen, Germany
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Tomescu AMF, Klymiuk AA, Matsunaga KKS, Bippus AC, Shelton GWK. Microbes and the Fossil Record: Selected Topics in Paleomicrobiology. THEIR WORLD: A DIVERSITY OF MICROBIAL ENVIRONMENTS 2016. [DOI: 10.1007/978-3-319-28071-4_3] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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McLoughlin N, Allen P, Antcliffe J, Green OR, Grosch EG, Hazen RM, Knoll A, McIlroy D, Menon L, Noffke N, Riding R. A Tribute to Martin D. Brasier: Palaeobiologist and Astrobiologist (April 12, 1947-December 16, 2014). ASTROBIOLOGY 2015; 15:940-948. [PMID: 26418424 DOI: 10.1089/ast.2015.1341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Affiliation(s)
- Nicola McLoughlin
- 1 Department of Earth Sciences, University of Bergen , Bergen, Norway
| | - Philip Allen
- 2 Department of Earth Science and Engineering, Imperial College London , London, UK
| | | | - Owen R Green
- 4 Department of Earth Sciences, University of Oxford , Oxford, UK
| | - Eugene G Grosch
- 1 Department of Earth Sciences, University of Bergen , Bergen, Norway
| | - Robert M Hazen
- 5 Carnegie Institution of Washington , Geophysical Laboratory, Washington, DC, USA
| | - Andrew Knoll
- 6 Department of Organismal and Evolutionary Biology, Harvard University , Cambridge, Massachusetts, USA
| | - Duncan McIlroy
- 7 Department of Earth Science, Memorial University , Newfoundland, Canada
| | - Latha Menon
- 4 Department of Earth Sciences, University of Oxford , Oxford, UK
- 8 Oxford University Press , Oxford, UK
| | - Nora Noffke
- 9 Ocean, Earth, and Atmospheric Sciences, Old Dominion University , Norfolk, Virginia, USA
| | - Robert Riding
- 10 Department of Earth and Planetary Sciences, University of Tennessee , Knoxville, Tennessee, USA
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Brasier M. Deep questions about the nature of early-life signals: a commentary on Lister (1673) 'A description of certain stones figured like plants'. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2015; 373:rsta.2014.0254. [PMID: 25750150 PMCID: PMC4360089 DOI: 10.1098/rsta.2014.0254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
In 1673, Martin Lister explored the preservation of 'St Cuthbert's beads' plus other fossil crinoid remains from approximately 350 Ma Carboniferous limestone in northern England. He used taphonomic evidence (transport, disarticulation, burial and cementation) to infer an origin as petrified plant remains, in contrast with his views expressed elsewhere that fossil mollusc shells could have formed abiogenically, by 'plastic forces' within rock. Lister also observed pentagonal symmetry, now seen as characteristic of living echinoderm skeletons. A postscript from John Ray supports Lister's 'taphonomic' observations and accepts the biogenicity of these fossil 'vegetables'. Ray then concluded with a prophecy, predicting the discovery of comparable living fossils in remote ocean waters. These early discussions compare with current debates about the character of candidate microfossils from the early Earth and Mars. Interesting biomorphs are now tested against the abiogenic null hypotheses, making use of features such as those pioneered by Lister, including evidence for geological context, rules for growth and taphonomy. Advanced techniques now allow us to extend this list of criteria to include the nanoscale mapping of biology-like behaviour patterns plus metabolic pathways. Whereas the science of palaeobiology once began with tests for biogenicity, the same is now true for geobiology and astrobiology. This commentary was written to celebrate the 350th anniversary of the journal Philosophical Transactions of the Royal Society.
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Affiliation(s)
- Martin Brasier
- Department of Earth Sciences, University of Oxford, South Parks Road, Oxford OX1 3AN, UK
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Coman C, Chiriac CM, Robeson MS, Ionescu C, Dragos N, Barbu-Tudoran L, Andrei AŞ, Banciu HL, Sicora C, Podar M. Structure, mineralogy, and microbial diversity of geothermal spring microbialites associated with a deep oil drilling in Romania. Front Microbiol 2015; 6:253. [PMID: 25870594 PMCID: PMC4378309 DOI: 10.3389/fmicb.2015.00253] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Accepted: 03/14/2015] [Indexed: 02/01/2023] Open
Abstract
Modern mineral deposits play an important role in evolutionary studies by providing clues to the formation of ancient lithified microbial communities. Here we report the presence of microbialite-forming microbial mats in different microenvironments at 32°C, 49°C, and 65°C around the geothermal spring from an abandoned oil drill in Ciocaia, Romania. The mineralogy and the macro- and microstructure of the microbialites were investigated, together with their microbial diversity based on a 16S rRNA gene amplicon sequencing approach. The calcium carbonate is deposited mainly in the form of calcite. At 32°C and 49°C, the microbialites show a laminated structure with visible microbial mat-carbonate crystal interactions. At 65°C, the mineral deposit is clotted, without obvious organic residues. Partial 16S rRNA gene amplicon sequencing showed that the relative abundance of the phylum Archaea was low at 32°C (<0.5%) but increased significantly at 65°C (36%). The bacterial diversity was either similar to other microbialites described in literature (the 32°C sample) or displayed a specific combination of phyla and classes (the 49°C and 65°C samples). Bacterial taxa were distributed among 39 phyla, out of which 14 had inferred abundances >1%. The dominant bacterial groups at 32°C were Cyanobacteria, Gammaproteobacteria, Firmicutes, Bacteroidetes, Chloroflexi, Thermi, Actinobacteria, Planctomycetes, and Defferibacteres. At 49°C, there was a striking dominance of the Gammaproteobacteria, followed by Firmicutes, Bacteroidetes, and Armantimonadetes. The 65°C sample was dominated by Betaproteobacteria, Firmicutes, [OP1], Defferibacteres, Thermi, Thermotogae, [EM3], and Nitrospirae. Several groups from Proteobacteria and Firmicutes, together with Halobacteria and Melainabacteria were described for the first time in calcium carbonate deposits. Overall, the spring from Ciocaia emerges as a valuable site to probe microbes-minerals interrelationships along thermal and geochemical gradients.
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Affiliation(s)
- Cristian Coman
- Taxonomy and Ecology, Algology, National Institute of Research and Development for Biological Sciences, Institute of Biological Research Cluj-Napoca, Romania ; Molecular Biology and Biotechnology Department, Faculty of Biology and Geology, Babeş-Bolyai University Cluj-Napoca, Romania
| | - Cecilia M Chiriac
- Taxonomy and Ecology, Algology, National Institute of Research and Development for Biological Sciences, Institute of Biological Research Cluj-Napoca, Romania ; Molecular Biology and Biotechnology Department, Faculty of Biology and Geology, Babeş-Bolyai University Cluj-Napoca, Romania
| | - Michael S Robeson
- Biosciences Division, Oak Ridge National Laboratory Oak Ridge, TN, USA ; Fish, Wildlife, and Conservation Biology, Colorado State University Fort Collins, CO, USA
| | - Corina Ionescu
- Geology Department, Faculty of Biology and Geology, Babeş-Bolyai University Cluj-Napoca, Romania ; Kazan (Volga Region) Federal University Tatarstan, Russia
| | - Nicolae Dragos
- Taxonomy and Ecology, Algology, National Institute of Research and Development for Biological Sciences, Institute of Biological Research Cluj-Napoca, Romania ; Molecular Biology and Biotechnology Department, Faculty of Biology and Geology, Babeş-Bolyai University Cluj-Napoca, Romania
| | - Lucian Barbu-Tudoran
- Electron Microscopy Center, Faculty of Biology and Geology, Babeş-Bolyai University Cluj-Napoca, Romania
| | - Adrian-Ştefan Andrei
- Molecular Biology and Biotechnology Department, Faculty of Biology and Geology, Babeş-Bolyai University Cluj-Napoca, Romania ; Molecular Biology Center, Institute for Interdisciplinary Research on Bio-Nano-Sciences, Babeş-Bolyai University Cluj-Napoca, Romania
| | - Horia L Banciu
- Molecular Biology and Biotechnology Department, Faculty of Biology and Geology, Babeş-Bolyai University Cluj-Napoca, Romania ; Molecular Biology Center, Institute for Interdisciplinary Research on Bio-Nano-Sciences, Babeş-Bolyai University Cluj-Napoca, Romania
| | | | - Mircea Podar
- Biosciences Division, Oak Ridge National Laboratory Oak Ridge, TN, USA
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Petryshyn VA, Lim D, Laval BL, Brady A, Slater G, Tripati AK. Reconstruction of limnology and microbialite formation conditions from carbonate clumped isotope thermometry. GEOBIOLOGY 2015; 13:53-67. [PMID: 25515686 DOI: 10.1111/gbi.12121] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Accepted: 09/17/2014] [Indexed: 06/04/2023]
Abstract
Quantitative tools for deciphering the environment of microbialite formation are relatively limited. For example, the oxygen isotope carbonate-water geothermometer requires assumptions about the isotopic composition of the water of formation. We explored the utility of using 'clumped' isotope thermometry as a tool to study the temperatures of microbialite formation. We studied microbialites recovered from water depths of 10-55 m in Pavilion Lake, and 10-25 m in Kelly Lake, spanning the thermocline in both lakes. We determined the temperature of carbonate growth and the (18)O/(16)O ratio of the waters that microbialites grew in. Results were then compared to current limnological data from the lakes to reconstruct the history of microbialite formation. Modern microbialites collected at shallow depths (11.7 m) in both lakes yield clumped isotope-based temperatures of formation that are within error of summer water temperatures, suggesting that clumped isotope analyses may be used to reconstruct past climates and to probe the environments in which microbialites formed. The deepest microbialites (21.7-55 m) were recovered from below the present-day thermoclines in both lakes and yield radioisotope ages indicating they primarily formed earlier in the Holocene. During this time, pollen data and our reconstructed water (18)O/(16)O ratios indicate a period of aridity, with lower lake levels. At present, there is a close association between both photosynthetic and heterotrophic communities, and carbonate precipitation/microbialite formation, with biosignatures of photosynthetic influences on carbonate detected in microbialites from the photic zone and above the thermocline (i.e., depths of generally <20 m). Given the deeper microbialites are receiving <1% of photosynthetically active radiation (PAR), it is likely these microbialites primarily formed when lower lake levels resulted in microbialites being located higher in the photic zone, in warm surface waters.
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Affiliation(s)
- V A Petryshyn
- Department of Earth, Planetary and Space Sciences, University of California, Los Angeles, CA, USA
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Antcliffe JB, Callow RHT, Brasier MD. Giving the early fossil record of sponges a squeeze. Biol Rev Camb Philos Soc 2014; 89:972-1004. [DOI: 10.1111/brv.12090] [Citation(s) in RCA: 126] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2012] [Revised: 01/16/2014] [Accepted: 01/30/2014] [Indexed: 11/27/2022]
Affiliation(s)
- Jonathan B. Antcliffe
- Department of Zoology; University of Oxford; South Parks Road Oxford OX1 3PS U.K
- Department of Earth Sciences; University of Bristol; Wills Memorial Building, Queen's Road Bristol BS81RJ U.K
| | - Richard H. T. Callow
- Department of Geology and Petroleum Geology; School of Geosciences, University of Aberdeen; Meston Building Aberdeen AB24 3UE U.K
| | - Martin D. Brasier
- Department of Earth Sciences; Oxford University; Parks Road Oxford OX13PR U.K
- Department of Earth Sciences; Memorial University of Newfoundland; 300 Prince Philip Drive St John's A1B 3X5 Canada
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Marin F, Le Roy N, Marie B, Ramos-Silva P, Bundeleva I, Guichard N, Immel F. Metazoan calcium carbonate biomineralizations: macroevolutionary trends – challenges for the coming decade. ACTA ACUST UNITED AC 2014. [DOI: 10.2113/gssgfbull.185.4.217] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Abstract
Calcium carbonate-based biominerals, also referred as biocalcifications, are the most abundant biogenic mineralized products at the surface of the Earth. In this paper, we summarize general concepts on biocalcifications and we sketch macro-evolutionary trends throughout the history of the Earth, from Archean to Phanerozoic times. Then, we expose five fundamental issues that represent key-challenges in biocalcification researches for the coming decade: the first one concerns the comprehension of the micro- and nano-structure of calcium carbonate biominerals from a mineral viewpoint, while the second one deals with the understanding of the dynamic process of their fabrication. The third one treats the subtle interplay between organics and the mineral phase. The fourth issue focuses on an environmental challenge related to ocean acidification (OA); at last, the diagenetic processes that affect biogenic calcium carbonate mineral constitute the fifth issue.
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Affiliation(s)
- Frédéric Marin
- UMR CNRS 6282 Biogéosciences, Université de Bourgogne, 6 boulevard Gabriel, 21000 Dijon, France
| | - Nathalie Le Roy
- UMR CNRS 6282 Biogéosciences, Université de Bourgogne, 6 boulevard Gabriel, 21000 Dijon, France
- Centre Scientifique de Monaco (CSM), 8 Quai Antoine Ier, MC 98000 Monaco
| | - Benjamin Marie
- UMR CNRS 7245 MCAM, Muséum National d’Histoire Naturelle (MNHN), 75005 Paris, France
| | - Paula Ramos-Silva
- UMR CNRS 6282 Biogéosciences, Université de Bourgogne, 6 boulevard Gabriel, 21000 Dijon, France
- Computational Science, Informatics Institute, Universiteit van Amsterdam, Science Park 904, 1098 XH, Amsterdam, Pays-Bas
- Computational Genomics Laboratory, Instituto Gulbenkian de Ciência, Rua da Quinta Grande, 6, 2780-156 Oeiras, Portugal
| | - Irina Bundeleva
- UMR CNRS 6282 Biogéosciences, Université de Bourgogne, 6 boulevard Gabriel, 21000 Dijon, France
| | - Nathalie Guichard
- UMR CNRS 6282 Biogéosciences, Université de Bourgogne, 6 boulevard Gabriel, 21000 Dijon, France
| | - Françoise Immel
- UMR CNRS 6282 Biogéosciences, Université de Bourgogne, 6 boulevard Gabriel, 21000 Dijon, France
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Berelson WM, Corsetti FA, Pepe-Ranney C, Hammond DE, Beaumont W, Spear JR. Hot spring siliceous stromatolites from Yellowstone National Park: assessing growth rate and laminae formation. GEOBIOLOGY 2011; 9:411-424. [PMID: 21777367 DOI: 10.1111/j.1472-4669.2011.00288.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Stromatolites are commonly interpreted as evidence of ancient microbial life, yet stromatolite morphogenesis is poorly understood. We apply radiometric tracer and dating techniques, molecular analyses and growth experiments to investigate siliceous stromatolite morphogenesis in Obsidian Pool Prime (OPP), a hot spring in Yellowstone National Park. We examine rates of stromatolite growth and the environmental and/or biologic conditions that affect lamination formation and preservation, both difficult features to constrain in ancient examples. The "main body" of the stromatolite is composed of finely laminated, porous, light-dark couplets of erect (surface normal) and reclining (surface parallel) silicified filamentous bacteria, interrupted by a less-distinct, well-cemented "drape" lamination. Results from dating studies indicate a growth rate of 1-5 cm year(-1) ; however, growth is punctuated. (14)C as a tracer demonstrates that stromatolite cyanobacterial communities fix CO(2) derived from two sources, vent water (radiocarbon dead) and the atmosphere (modern (14)C). The drape facies contained a greater proportion of atmospheric CO(2) and more robust silica cementation (vs. the main body facies), which we interpret as formation when spring level was lower. Systematic changes in lamination style are likely related to environmental forcing and larger scale features (tectonic, climatic). Although the OPP stromatolites are composed of silica and most ancient forms are carbonate, their fine lamination texture requires early lithification. Without early lithification, whether silica or carbonate, it is unlikely that a finely laminated structure representing an ancient microbial mat would be preserved. In OPP, lithification on the nearly diurnal time scale is likely related to temperature control on silica solubility.
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Affiliation(s)
- W M Berelson
- Department of Earth Sciences, University of Southern California, Los Angeles, CA, USA.
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28
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Stevens EW, Sumner DY, Harwood CL, Crutchfield JP, Hamann B, Kreylos O, Puckett E, Senge P. Understanding microbialite morphology using a comprehensive suite of three-dimensional analysis tools. ASTROBIOLOGY 2011; 11:509-518. [PMID: 21740150 DOI: 10.1089/ast.2010.0560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Microbialites can have complex morphologies that preserve clues to ancient microbial ecology. However, extracting and interpreting these clues is challenging due to both the complexity of microbial structures and the difficulties of connecting morphology to microbial processes. Fenestrate microbialites from the 2521±3 Ma Gamohaan Formation, South Africa, have intricate structures composed of three distinct microbial structures: steeply dipping supports (surfaces defined by organic inclusions), more shallowly dipping supports with diffuse organic inclusions below them, and draping laminae. In polished slabs, shallowly dipping supports with diffuse organic inclusions show apparent dips from 27° to 60°, and supports without associated zones of diffuse inclusions dip 75° to 88°, which suggests a distinction between support types based on orientation. However, dips exposed in polished slabs are apparent dips, and three-dimensional analysis is required for analysis of true dips. Through the Keck Center for Active Visualization in Earth Sciences (KeckCAVES), we used locally developed software that controls a three-dimensional environment with head and hand tracking (an "immersive environment") to visualize and interpret virtual microbialite data sets. Immersive environments have not penetrated into standard scientific work processes ("workflows") due to their high costs, steep learning curves, and low productivity for users. By contrast, our suite of software tools allowed us to develop a personalized scientific workflow that provides a complete path from initial ideas to characterization of fenestrate microbialites' features. Results of three-dimensional analysis of fenestrate microbialites show that supports with inclusions dip 65° to 75°, whereas supports without inclusions dip 85° to 90°. These results demonstrate that all supports have very steep dips, and a 10° dip gap exists between supports with and without inclusions, which suggests they grew in fundamentally different ways. Results also emphasize how valuable three-dimensional analysis is when combined with a comprehensive workflow for understanding intricate structures such as fenestrate microbialites.
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Affiliation(s)
- Eric W Stevens
- Department of Geology, University of California, Davis, CA 95616, USA
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29
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Elemental and Isotopic Analysis by NanoSIMS: Insights for the Study of Stromatolites and Early Life on Earth. ACTA ACUST UNITED AC 2011. [DOI: 10.1007/978-94-007-0397-1_21] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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31
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Riding R. The Nature of Stromatolites: 3,500 Million Years of History and a Century of Research. ADVANCES IN STROMATOLITE GEOBIOLOGY 2011. [DOI: 10.1007/978-3-642-10415-2_3] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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Wacey D, Gleeson D, Kilburn MR. Microbialite taphonomy and biogenicity: new insights from NanoSIMS. GEOBIOLOGY 2010; 8:403-416. [PMID: 20597990 DOI: 10.1111/j.1472-4669.2010.00251.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
We here show that nano-scale mapping of elements commonly utilized in biological cycles provides a promising new additional line of evidence when evaluating the extent of the contribution of biology to microbialites. Our case study comes from Lake Clifton in Western Australia, a unique environment where living domical and conical microbialites occur in close proximity to ≤ 4000-year-old fossilized equivalents. The outer margins of a partially lithified, actively growing Lake Clifton microbialite are characterized by abundant filamentous cyanobacteria within a loosely cemented aragonite matrix. Nano-scale chemical maps have been successfully matched to specific morphological features such as trichomes, sheaths and putative extracellular polymeric substances (EPS). A suite of elements (C, O, Mg, N, Si, S) is concentrated within cyanobacterial sheaths, with carbon, magnesium, nitrogen and sulfur also enriched within trichomes and putative EPS. Calcium distribution highlights the sites of aragonite mineralization. In contrast, the fossilized Lake Clifton microbialite contains only rare, extensively degraded cyanobacterial filaments, the mean diameter of which is <50% of the living equivalents. Nevertheless, nano-scale chemical maps can again be matched with morphological features. Here, poorly preserved filamentous microfossils are highlighted by enrichments in nitrogen and sulfur. Magnesium is no longer concentrated within the filaments, instead it co-occurs with calcium and oxygen in the calcite cement. Extension of this study to a ~2720-million-year-old stromatolitic microbialite from the Tumbiana Formation of Western Australia shows that similar nano-scale signals, in particular nitrogen and sulfur enrichments, are characteristic of stromatolite laminations, even when morphological microfossils are absent. The close similarities of nano-scale elemental distributions in organic material from modern and ancient microbialites show that this technique provides a valuable addition to the morphological investigation of such structures, particularly in non-fossiliferous ancient examples.
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Affiliation(s)
- D Wacey
- Centre for Microscopy, Characterisation and Analysis, The University of Western Australia, Crawley, WA, Australia.
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Sugitani K, Lepot K, Nagaoka T, Mimura K, Van Kranendonk M, Oehler DZ, Walter MR. Biogenicity of morphologically diverse carbonaceous microstructures from the ca. 3400 Ma Strelley pool formation, in the Pilbara Craton, Western Australia. ASTROBIOLOGY 2010; 10:899-920. [PMID: 21118023 DOI: 10.1089/ast.2010.0513] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Morphologically diverse structures that may constitute organic microfossils are reported from three remote and widely separated localities assigned to the ca. 3400 Ma Strelley Pool Formation in the Pilbara Craton, Western Australia. These localities include the Panorama, Warralong, and Goldsworthy greenstone belts. From the Panorama greenstone belt, large (> 40 μm) lenticular to spindle-like structures, spheroidal structures, and mat-forming thread-like structures are found. Similar assemblages of carbonaceous structures have been identified from the Warralong and Goldsworthy greenstone belts, though these assemblages lack the thread-like structures but contain film-like structures. All structures are syngenetic with their host sedimentary black chert, which is associated with stromatolites and evaporites. The host chert is considered to have been deposited in a shallow water environment. Rigorous assessment of biogenicity (considering composition, size range, abundance, taphonomic features, and spatial distributions) suggests that cluster-forming small (<15 μm) spheroids, lenticular to spindle-like structures, and film-like structures with small spheroids are probable microfossils. Thread-like structures are more likely fossilized fibrils of biofilm, rather than microfossils. The biogenicity of solitary large (>15 μm) spheroids and simple film-like structures is less certain. Although further investigations are required to confirm the biogenicity of carbonaceous structures from the Strelley Pool Formation, this study presents evidence for the existence of morphologically complex and large microfossils at 3400 Ma in the Pilbara Craton, which can be correlated to the contemporaneous, possible microfossils reported from South Africa. Although there is still much to be learned, they should provide us with new insights into the early evolution of life and shallow water ecosystems.
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Affiliation(s)
- Kenichiro Sugitani
- Department of Environmental Engineering and Architecture, Graduate School of Environmental Studies, Nagoya University, Nagoya, Japan.
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Benzerara K, Meibom A, Gautier Q, Kaźmierczak J, Stolarski J, Menguy N, Brown GE. Nanotextures of aragonite in stromatolites from the quasi-marine Satonda crater lake, Indonesia. ACTA ACUST UNITED AC 2010. [DOI: 10.1144/sp336.10] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
AbstractStromatolites have been extensively used as indicators of ancient life on Earth. Although much work has been done on modern stromatolites, the extent to which biological processes control their structure, and the respective contributions of biological and abiotic processes in their formation are, however, still poorly constrained. A better description of the mineralogical textures of these formations at the submicrometre scale may help improve our understanding of how carbonates nucleate and grow in stromatolites. Here, we used a combination of microscopy and microspectroscopy techniques to study the chemical composition and the texture of aragonite in lacustrine stromatolites from the alkaline crator lake in Satonda, Indonesia. Several textural features are described, including morphological variations of aragonite from nanosized grains to micrometre-sized fibres, the presence of striations in the aragonite laminae showing a striking similarity with growth bands in corals, and clusters of small aragonite crystals sharing a common crystallographic orientation. These nanotextural features are compared with those observed in scleractinian corals, and possible processes involved in their formation are discussed.
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Affiliation(s)
- Karim Benzerara
- Equipe Géobiosphère Actuelle et Primitive, IMPMC & IPGP, UMR 7590, CNRS, Universités Paris 6 et IPGP. 140, rue de Lourmel, 75015 Paris, France
| | - Anders Meibom
- Muséum National d'Histoire Naturelle, Laboratoire de Minéralogie et Cosmochimie du Muséum (LMCM), UMR 7202, Paris, France
| | - Quentin Gautier
- Equipe Géobiosphère Actuelle et Primitive, IMPMC & IPGP, UMR 7590, CNRS, Universités Paris 6 et IPGP. 140, rue de Lourmel, 75015 Paris, France
| | - Józef Kaźmierczak
- Institute of Paleobiology, Polish Academy of Sciences, Twarda 51/55, 00818 Warsaw, Poland
| | - Jarosław Stolarski
- Institute of Paleobiology, Polish Academy of Sciences, Twarda 51/55, 00818 Warsaw, Poland
| | - Nicolas Menguy
- Equipe Géobiosphère Actuelle et Primitive, IMPMC & IPGP, UMR 7590, CNRS, Universités Paris 6 et IPGP. 140, rue de Lourmel, 75015 Paris, France
| | - Gordon E. Brown
- Surface & Aqueous Geochemistry Group, Department of Geological & Environmental Sciences, Stanford University, Stanford, CA 94305-2115, USA
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
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Shepard RN, Sumner DY. Undirected motility of filamentous cyanobacteria produces reticulate mats. GEOBIOLOGY 2010; 8:179-90. [PMID: 20345889 DOI: 10.1111/j.1472-4669.2010.00235.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
The roles of biology in the morphogenesis of microbial mats and stromatolites remain enigmatic due to the vast array of physical and chemical influences on morphology. However, certain microbial behaviors produce complex morphological features that can be directly attributed to motility patterns. Specifically, laboratory experiments with a strain of the cyanobacteria Pseudanabaena demonstrate that distinctive morphologies arise from the undirected gliding and colliding of filaments. When filamentous cells collide, they align and clump, producing intersecting ridges surrounding areas with low cell density, i.e. reticulate structures. Cell motility is essential for the development of reticulates and associated structures: filaments organize into reticulates faster than cell division and growth, and conditions that inhibit motility also inhibit reticulate formation. Cell density of the inoculum affects the frequency of cell-cell collisions, and thus the time required for biofilm organization into reticulate structures. This also affects the specific geometry of the reticulates. These patterns are propagated into larger structures as cyanobacterial cell numbers increase and cells remain motile. Thus, cell motility is important for templating and maintaining the morphology of these microbial communities, demonstrating a direct link between a microbial behavior and a community morphology. Reticulate geometries have been identified in natural microbial mats as well as in the fossil record, and these structures can be attributed to the motility of filamentous bacteria.
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Affiliation(s)
- R N Shepard
- Department of Geology, University of California, Davis, CA, USA
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Wagstaff KL, Corsetti FA. An evaluation of information-theoretic methods for detecting structural microbial biosignatures. ASTROBIOLOGY 2010; 10:363-379. [PMID: 20528192 DOI: 10.1089/ast.2008.0301] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The first observations of extraterrestrial environments will most likely be in the form of digital images. Given an image of a rock that contains layered structures, is it possible to determine whether the layers were created by life (biogenic)? While conclusive judgments about biogenicity are unlikely to be made solely on the basis of image features, an initial assessment of the importance of a given sample can inform decisions about follow-up searches for other types of possible biosignatures (e.g., isotopic or chemical analysis). In this study, we evaluated several quantitative measures that capture the degree of complexity in visible structures, in terms of compressibility (to detect order) and the entropy (spread) of their intensity distributions. Computing complexity inside a sliding analysis window yields a map of each of these features that indicates how they vary spatially across the sample. We conducted experiments on both biogenic and abiogenic terrestrial stromatolites and on laminated structures found on Mars. The degree to which each feature separated biogenic from abiogenic samples (separability) was assessed quantitatively. None of the techniques provided a consistent, statistically significant distinction between all biogenic and abiogenic samples. However, the PNG compression ratio provided the strongest distinction (2.80 in standard deviation units) and could inform future techniques. Increasing the analysis window size or the magnification level, or both, improved the separability of the samples. Finally, data from all four Mars samples plotted well outside the biogenic field suggested by the PNG analyses, although we caution against a direct comparison of terrestrial stromatolites and martian non-stromatolites.
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Affiliation(s)
- Kiri L Wagstaff
- Machine Learning and Instrument Autonomy Group, Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109, USA.
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Wacey D. Stromatolites in the approximately 3400 Ma Strelley Pool Formation, Western Australia: examining biogenicity from the macro- to the nano-scale. ASTROBIOLOGY 2010; 10:381-395. [PMID: 20528193 DOI: 10.1089/ast.2009.0423] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The 3426-3350 Ma Strelley Pool Formation (SPF) is a silicified, dominantly sedimentary unit within the Pilbara Supergroup, Western Australia. It is found widely across the East Pilbara Terrane, and it forms a prominent marker horizon and separates the largely volcanic 3520-3427 Ma Warrawoona and 3350-3315 Ma Kelly groups. It has become one of the key formations for study by astrobiologists, following reports of some of the world's oldest stromatolites. Abundant contextural and morphological evidence has been presented over the last decade in support of a biological role in SPF stromatolite formation. This evidence is reviewed here, and additional data are presented from recent fieldwork carried out across the approximately 25 km of SPF outcrops in the East Strelley greenstone belt of the East Pilbara Terrane. In addition to contextural and morphological evidence, a compelling claim for early life requires geochemical evidence for biological cycling. A potential avenue of approach to obtain such evidence for the SPF stromatolites (and other ancient examples) is discussed in the context of a pilot study in which nano-scale secondary ion mass spectrometry (NanoSIMS) was used.
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Affiliation(s)
- David Wacey
- Centre for Microscopy, Characterisation and Analysis, and the School of Earth and Environment, The University of Western Australia, Crawley, Australia.
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Bailey JV, Orphan VJ, Joye SB, Corsetti FA. Chemotrophic microbial mats and their potential for preservation in the rock record. ASTROBIOLOGY 2009; 9:843-859. [PMID: 19968462 DOI: 10.1089/ast.2008.0314] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Putative microbialites are commonly regarded to have formed in association with photosynthetic microorganisms, such as cyanobacteria. However, many modern microbial mat ecosystems are dominated by chemotrophic bacteria and archaea. Like phototrophs, filamentous sulfur-oxidizing bacteria form large mats at the sediment/water interface that can act to stabilize sediments, and their metabolic activities may mediate the formation of marine phosphorites. Similarly, bacteria and archaea associated with the anaerobic oxidation of methane (AOM) catalyze the precipitation of seafloor authigenic carbonates. When preserved, lipid biomarkers, isotopic signatures, body fossils, and lithological indicators of the local depositional environment may be used to identify chemotrophic mats in the rock record. The recognition of chemotrophic communities in the rock record has the potential to transform our understanding of ancient microbial ecologies, evolution, and geochemical conditions. Chemotrophic microbes on Earth occupy naturally occurring interfaces between oxidized and reduced chemical species and thus may provide a new set of search criteria to target life-detection efforts on other planets.
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Affiliation(s)
- Jake V Bailey
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California 91125, USA.
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Krinsley D, Dorn RI, DiGregorio B. Astrobiological implications of rock varnish in Tibet. ASTROBIOLOGY 2009; 9:551-562. [PMID: 19663762 DOI: 10.1089/ast.2008.0238] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The study of terrestrial geomicrobiology and its relationship to rock weathering processes is an essential tool in developing analogues for similar processes that may have occurred on Mars. Most studies of manganese-enhanced rock varnish have focused on samples taken from warm arid desert regions. Here, we examine samples obtained from eolian-abraded lava flows of the 4700-4800 m high Ashikule Basin in Tibet. Because it receives approximately 300 mm of precipitation annually, this site is nowhere near as dry as Atacama Desert locales. However, the dusty, sulfate-rich, high-altitude and high-UV flux environment of the Tibetan locale offers new insight into rock varnish formation processes in a terrestrial environment that displays some attributes similar to those expected on early Mars. Microprobe measurements reveal that Mn enhancements in varnish are two orders of magnitude above the dust source, but Fe is only enhanced by a factor of three. Manganese-enhancing bacterial forms are not abundant but are still approximately 3 times more common than in Mojave and Sonoran Desert varnishes. In addition to its occurrence in subaerial positions, Tibetan varnish also occurs in micron-scale "pods" enveloped by silica glaze and as remobilized constituents that have migrated into the underlying weathering rind. A lack of surficial Mn-rich varnish, therefore, might not imply the absence of varnish. In contrast to suggestions that silica glaze might be a good source of microbial fossils and a key to varnish formation, we did not observe any clear microfossil forms entombed in silica glaze; further, there is no gradation between varnish and silica glaze but only distinct contacts.
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Affiliation(s)
- David Krinsley
- Department of Geological Sciences, University of Oregon, Eugene, Oregon 97403-1272, USA.
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Raven JA, Giordano M. Biomineralization by photosynthetic organisms: evidence of coevolution of the organisms and their environment? GEOBIOLOGY 2009; 7:140-54. [PMID: 19207569 DOI: 10.1111/j.1472-4669.2008.00181.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Biomineralization is widespread among photosynthetic organisms in the ocean, in inland waters and on land. The most quantitatively important biogeochemical role of land plants today in biomineralization is silica deposition in vascular plants, especially grasses. Terrestrial plants also increase the rate of weathering, providing the soluble substrates for biomineralization on land and in water bodies, a role that has had global biogeochemical impacts since the Devonian. The dominant photosynthetic biomineralizers in today's ocean are diatoms and radiolarians depositing silica and coccolithophores and foraminifera depositing calcium carbonate. Abiotic precipitation of silica from supersaturated seawater in the Precambrian preceded intracellular silicification dominated by sponges, then radiolarians and finally diatoms, with successive declines in the silicic acid concentration in the surface ocean, resulting in some decreases in the extent of silicification and, probably, increases in the silicic acid affinity of the active influx mechanisms. Calcium and bicarbonate concentrations in the surface ocean have generally been supersaturating with respect to the three common calcium carbonate biominerals through geological time, allowing external calcification as well as calcification in compartments within cells or organisms. The forms of calcium carbonate in biominerals, and presumably the evolution of the organisms that produce them, have been influenced by abiotic variations in calcium and magnesium concentrations in seawater, and calcium carbonate deposition has probably also been influenced by carbon dioxide concentration whose variations are in part biologically determined. Overall, there has been less biological feedback on the availability of substrates for calcification than is the case for silicification.
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Affiliation(s)
- J A Raven
- Division of Plant Sciences, University of Dundee at SCRI, Scottish Crop Research Institute, Dundee, UK.
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Affiliation(s)
- Frances Westall
- Centre de Biophysique Moléculaire, CNRS and Université d'Orléans, Rue Charles Sadron, 45071 Orléans cedex 2, France
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