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Broz A, Aguilar J, Xu X, Silva LCR. Accumulation of radiocarbon in ancient landscapes: A small but significant input of unknown origin. Sci Rep 2023; 13:7476. [PMID: 37156787 PMCID: PMC10167333 DOI: 10.1038/s41598-023-34080-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2022] [Accepted: 04/24/2023] [Indexed: 05/10/2023] Open
Abstract
The persistence of organic carbon (C) in soil is most often considered at timescales ranging from tens to thousands of years, but the study of organic C in paleosols (i.e., ancient, buried soils) suggests that paleosols may have the capacity to preserve organic compounds for tens of millions of years. However, a quantitative assessment of C sources and sinks from these ancient terrestrial landscapes is complicated by additions of geologically modern (~ 10 Ka) C, primarily due to the infiltration of dissolved organic carbon. In this study, we quantified total organic C and radiocarbon activity in samples collected from 28- to 33-million-year-old paleosols that are naturally exposed as unvegetated badlands near eastern Oregon's "Painted Hills". We also used thermal and evolved gas analysis to examine the thermodynamic stability of different pools of C in bulk samples. The study site is part of a ~ 400-m-thick sequence of Eocene-Oligocene (45-28 Ma) paleosols, and thus we expected to find radiocarbon-free samples preserved in deep layers of the lithified, brick-like exposed outcrops. Total organic C, measured in three individual profiles spanning depth transects from the outcrop surface to a 1-m depth, ranged from 0.01 to 0.2 wt% with no clear C-concentration or age-depth profile. Ten radiocarbon dates from the same profiles reveal radiocarbon ages of ~ 11,000-30,000 years BP that unexpectedly indicate additions of potentially modern organic C. A two-endmember mixing model for radiocarbon activity suggests that modern C may compose ~ 0.5-2.4% of the total organic C pool. Thermal and evolved gas analysis showed the presence of two distinct pools of organic C, but there was no direct evidence that C compounds were associated with clay minerals. These results challenge the assumption that ancient badland landscapes are inert and "frozen in time" and instead suggest they readily interact with the modern C cycle.
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Affiliation(s)
- Adrian Broz
- Department of Earth, Atmospheric and Planetary Sciences, Purdue University, West Lafayette, IN, 47907, USA.
- Department of Earth Sciences, University of Oregon, Eugene, OR, 97403, USA.
| | - Jerod Aguilar
- Department of Earth Sciences, Southern Methodist University, Dallas, TX, 97403, USA
| | - Xiaomei Xu
- University of California Irvine, Irvine, CA, 92697, USA
| | - Lucas C R Silva
- Department of Geography, University of Oregon, Eugene, OR, 97403, USA
- Environmental Studies, Department of Biology, Institute of Ecology and Evolution, University of Oregon, Eugene, OR, 97403, USA
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2
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Messmer MW, Dieser M, Smith HJ, Parker AE, Foreman CM. Investigation of Raman Spectroscopic Signatures with Multivariate Statistics: An Approach for Cataloguing Microbial Biosignatures. ASTROBIOLOGY 2022; 22:14-24. [PMID: 34558961 DOI: 10.1089/ast.2021.0021] [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: 06/13/2023]
Abstract
Spectroscopic instruments are increasingly being implemented in the search for extraterrestrial life. However, microstructural spectral analyses of alien environments could prove difficult without knowledge on the molecular identification of individual spectral signatures. To bridge this gap, we introduce unsupervised K-means clustering as a statistical approach to discern spectral patterns of biosignatures without prior knowledge of spectral regions of biomolecules. Spectral profiles of bacterial isolates from analogous polar ice sheets were measured with Raman spectroscopy. Raman analysis identified carotenoid and violacein pigments, and key cellular features including saturated and unsaturated fats, triacylglycerols, and proteins. Principal component analysis and targeted spectra integration biplot analysis revealed that the clustering of bacterial isolates was attributed to spectral biosignatures influenced by carotenoid pigments and ratio of unsaturated/saturated fat peaks. Unsupervised K-means clustering highlighted the prevalence of the corresponding spectral peaks, while subsequent supervised permutational multivariate analysis of variance provided statistical validation for spectral differences associated with the identified cellular features. Establishing a validated catalog of spectral signatures of analogous biotic and abiotic materials, in combination with targeted supervised tools, could prove effective at identifying extant biosignatures.
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Affiliation(s)
- Mitch W Messmer
- Center for Biofilm Engineering, Montana State University, Bozeman, Montana, USA
- Department of Chemical & Biological Engineering, Montana State University, Bozeman, Montana, USA
| | - Markus Dieser
- Center for Biofilm Engineering, Montana State University, Bozeman, Montana, USA
- Department of Chemical & Biological Engineering, Montana State University, Bozeman, Montana, USA
| | - Heidi J Smith
- Center for Biofilm Engineering, Montana State University, Bozeman, Montana, USA
- Department of Microbiology and Cell Biology, and Montana State University, Bozeman, Montana, USA
| | - Albert E Parker
- Center for Biofilm Engineering, Montana State University, Bozeman, Montana, USA
- Department of Mathematical Sciences, Montana State University, Bozeman, Montana, USA
| | - Christine M Foreman
- Center for Biofilm Engineering, Montana State University, Bozeman, Montana, USA
- Department of Chemical & Biological Engineering, Montana State University, Bozeman, Montana, USA
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3
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Broz AP. Organic Matter Preservation in Ancient Soils of Earth and Mars. Life (Basel) 2020; 10:E113. [PMID: 32708606 PMCID: PMC7400377 DOI: 10.3390/life10070113] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2020] [Revised: 06/28/2020] [Accepted: 07/11/2020] [Indexed: 11/21/2022] Open
Abstract
The emerging field of astropedology is the study of ancient soils on Earth and other planetary bodies. Examination of the complex factors that control the preservation of organic matter and other biosignatures in ancient soils is a high priority for current and future missions to Mars. Though previously defined by biological activity, an updated definition of soil as planetary surfaces altered in place by biological, chemical or physical processes was adopted in 2017 by the Soil Science Society of America in response to mounting evidence of pedogenic-like features on Mars. Ancient (4.1-3.7 billion year old [Byr]) phyllosilicate-rich surface environments on Mars show evidence of sustained subaerial weathering of sediments with liquid water at circumneutral pH, which is a soil-forming process. The accumulation of buried, fossilized soils, or paleosols, has been widely observed on Earth, and recent investigations suggest paleosol-like features may be widespread across the surface of Mars. However, the complex array of preservation and degradation factors controlling the fate of biosignatures in paleosols remains unexplored. This paper identifies the dominant factors contributing to the preservation and degradation of organic carbon in paleosols through the geological record on Earth, and offers suggestions for prioritizing locations for in situ biosignature detection and Mars Sample Return across a diverse array of potential paleosols and paleoenvironments of early Mars. A compilation of previously published data and original research spanning a diverse suite of paleosols from the Pleistocene (1 Myr) to the Archean (3.7 Byr) show that redox state is the predominant control for the organic matter content of paleosols. Most notably, the chemically reduced surface horizons (layers) of Archean (2.3 Byr) paleosols have organic matter concentrations ranging from 0.014-0.25%. However, clay mineralogy, amorphous phase abundance, diagenetic alteration and sulfur content are all significant factors that influence the preservation of organic carbon. The surface layers of paleosols that formed under chemically reducing conditions with high amounts of iron/magnesium smectites and amorphous colloids should be considered high priority locations for biosignature investigation within subaerial paleoenvironments on Mars.
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Affiliation(s)
- Adrian P Broz
- Department of Earth Sciences, University of Oregon, Eugene, OR 97405, USA
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Thomazo C, Couradeau E, Giraldo-Silva A, Marin-Carbonne J, Brayard A, Homann M, Sansjofre P, Lalonde SV, Garcia-Pichel F. Biological Soil Crusts as Modern Analogs for the Archean Continental Biosphere: Insights from Carbon and Nitrogen Isotopes. ASTROBIOLOGY 2020; 20:815-819. [PMID: 32293913 DOI: 10.1089/ast.2019.2144] [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
Stable isotope signatures of elements related to life such as carbon and nitrogen can be powerful biomarkers that provide key information on the biological origin of organic remains and their paleoenvironments. Marked advances have been achieved in the last decade in our understanding of the coupled evolution of biological carbon and nitrogen cycling and the chemical evolution of the early Earth thanks, in part, to isotopic signatures preserved in fossilized microbial mats and organic matter of marine origin. However, the geologic record of the early continental biosphere, as well as its evolution and biosignatures, is still poorly constrained. Following a recent report of direct fossil evidence of life on land at 3.22 Ga, we compare here the carbon and nitrogen isotopic signals of this continental Archean biosphere with biosignatures of cyanobacteria biological soil crusts (cyanoBSCs) colonizing modern arid environments. We report the first extended δ13C and δ15N data set from modern cyanoBSCs and show that these modern communities harbor specific isotopic biosignatures that compare well with continental Archean organic remains. We therefore suggest that cyanoBSCs are likely relevant analogs for the earliest continental ecosystems. As such, they can provide key information on the timing, extent, and possibly mechanism of colonization of the early Earth's emergent landmasses.
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Affiliation(s)
- Christophe Thomazo
- Biogéosciences, UMR6282, CNRS, Université Bourgogne Franche-Comté, Dijon, France
| | - Estelle Couradeau
- Joint Genome Institute, Lawrence Berkeley National Lab, Walnut Creek, California
| | - Anna Giraldo-Silva
- Center for Fundamental and Applied Microbiomics, Biodesign Institute, and School of Life Sciences, Arizona State University, Tempe, Arizona
| | | | - Arnaud Brayard
- Biogéosciences, UMR6282, CNRS, Université Bourgogne Franche-Comté, Dijon, France
| | - Martin Homann
- European Institute for Marine Studies, CNRS-UMR6538, Laboratoire Géosciences Océan, Technopôle Brest-Iroise, Plouzané, France
- Department of Earth Sciences, University College London, London, United Kingdom
| | - Pierre Sansjofre
- European Institute for Marine Studies, CNRS-UMR6538, Laboratoire Géosciences Océan, Technopôle Brest-Iroise, Plouzané, France
- MNHN, Sorbonne Université, CNRS UMR 7590, IRD, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, Paris, France
| | - Stefan V Lalonde
- European Institute for Marine Studies, CNRS-UMR6538, Laboratoire Géosciences Océan, Technopôle Brest-Iroise, Plouzané, France
| | - Ferran Garcia-Pichel
- Center for Fundamental and Applied Microbiomics, Biodesign Institute, and School of Life Sciences, Arizona State University, Tempe, Arizona
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Colwyn DA, Sheldon ND, Maynard JB, Gaines R, Hofmann A, Wang X, Gueguen B, Asael D, Reinhard CT, Planavsky NJ. A paleosol record of the evolution of Cr redox cycling and evidence for an increase in atmospheric oxygen during the Neoproterozoic. GEOBIOLOGY 2019; 17:579-593. [PMID: 31436043 DOI: 10.1111/gbi.12360] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Revised: 07/05/2019] [Accepted: 07/29/2019] [Indexed: 06/10/2023]
Abstract
Atmospheric oxygen levels control the oxidative side of key biogeochemical cycles and place limits on the development of high-energy metabolisms. Understanding Earth's oxygenation is thus critical to developing a clearer picture of Earth's long-term evolution. However, there is currently vigorous debate about even basic aspects of the timing and pattern of the rise of oxygen. Chemical weathering in the terrestrial environment occurs in contact with the atmosphere, making paleosols potentially ideal archives to track the history of atmospheric O2 levels. Here we present stable chromium isotope data from multiple paleosols that offer snapshots of Earth surface conditions over the last three billion years. The results indicate a secular shift in the oxidative capacity of Earth's surface in the Neoproterozoic and suggest low atmospheric oxygen levels (<1% PAL pO2 ) through the majority of Earth's history. The paleosol record also shows that localized Cr oxidation may have begun as early as the Archean, but efficient, modern-like transport of hexavalent Cr under an O2 -rich atmosphere did not become common until the Neoproterozoic.
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Affiliation(s)
| | - Nathan D Sheldon
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI, USA
| | - J Barry Maynard
- Department of Geology, University of Cincinnati, Cincinnati, OH, USA
| | - Robert Gaines
- Geology Department, Pomona College, Claremont, CA, USA
| | - Axel Hofmann
- Department of Geology, University of Johannesburg, Johannesburg, South Africa
| | - Xiangli Wang
- Department of Geology and Geophysics, Yale University, New Haven, CT, USA
- Department of Marine Sciences, University of South Alabama, Mobile, AL, USA
- Dauphin Island Sea Lab, Dauphin Island, AL, USA
| | - Bleuenn Gueguen
- Department of Geology and Geophysics, Yale University, New Haven, CT, USA
- Institut Universitaire Européen de la Mer, CNRS UMS 3113, Université de Brest, Plouzané, France
| | - Dan Asael
- Department of Geology and Geophysics, Yale University, New Haven, CT, USA
| | - Christopher T Reinhard
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - Noah J Planavsky
- Department of Geology and Geophysics, Yale University, New Haven, CT, USA
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6
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Schad M, Konhauser KO, Sánchez-Baracaldo P, Kappler A, Bryce C. How did the evolution of oxygenic photosynthesis influence the temporal and spatial development of the microbial iron cycle on ancient Earth? Free Radic Biol Med 2019; 140:154-166. [PMID: 31323314 DOI: 10.1016/j.freeradbiomed.2019.07.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Revised: 07/05/2019] [Accepted: 07/15/2019] [Indexed: 12/22/2022]
Abstract
Iron is the most abundant redox active metal on Earth and thus provides one of the most important records of the redox state of Earth's ancient atmosphere, oceans and landmasses over geological time. The most dramatic shifts in the Earth's iron cycle occurred during the oxidation of Earth's atmosphere. However, tracking the spatial and temporal development of the iron cycle is complicated by uncertainties about both the timing and location of the evolution of oxygenic photosynthesis, and by the myriad of microbial processes that act to cycle iron between redox states. In this review, we piece together the geological evidence to assess where and when oxygenic photosynthesis likely evolved, and attempt to evaluate the influence of this innovation on the microbial iron cycle.
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Affiliation(s)
- Manuel Schad
- Geomicrobiology, Center for Applied Geosciences, University of Tübingen, 72076, Tübingen, Germany
| | - Kurt O Konhauser
- Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, AB T6G 2E3, Canada
| | | | - Andreas Kappler
- Geomicrobiology, Center for Applied Geosciences, University of Tübingen, 72076, Tübingen, Germany
| | - Casey Bryce
- Geomicrobiology, Center for Applied Geosciences, University of Tübingen, 72076, Tübingen, Germany.
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7
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Sand KK, Jelavić S. Mineral Facilitated Horizontal Gene Transfer: A New Principle for Evolution of Life? Front Microbiol 2018; 9:2217. [PMID: 30319562 PMCID: PMC6167411 DOI: 10.3389/fmicb.2018.02217] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Accepted: 08/30/2018] [Indexed: 11/22/2022] Open
Abstract
A number of studies have highlighted that adsorption to minerals increases DNA longevity in the environment. Such DNA-mineral associations can essentially serve as pools of genes that can be stored across time. Importantly, this DNA is available for incorporation into alien organisms through the process of horizontal gene transfer (HGT). Here we argue that minerals hold an unrecognized potential for successfully transferring genetic material across environments and timescales to distant organisms and hypothesize that this process has significantly influenced the evolution of life. Our hypothesis is illustrated in the context of the evolution of early microbial life and the oxygenation of the Earth's atmosphere and offers an explanation for observed outbursts of evolutionary events caused by HGT.
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Affiliation(s)
- Karina Krarup Sand
- Department of Geography and Earth Sciences, Aberystwyth University, Aberystwyth, United Kingdom
- Nano-Science Center, Department of Chemistry, University of Copenhagen, Copenhagen, Denmark
| | - Stanislav Jelavić
- Nano-Science Center, Department of Chemistry, University of Copenhagen, Copenhagen, Denmark
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8
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Thomazo C, Couradeau E, Garcia-Pichel F. Possible nitrogen fertilization of the early Earth Ocean by microbial continental ecosystems. Nat Commun 2018; 9:2530. [PMID: 29955055 PMCID: PMC6023897 DOI: 10.1038/s41467-018-04995-y] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Accepted: 06/07/2018] [Indexed: 01/30/2023] Open
Abstract
While significant efforts have been invested in reconstructing the early evolution of the Earth's atmosphere-ocean-biosphere biogeochemical nitrogen cycle, the potential role of an early continental contribution by a terrestrial, microbial phototrophic biosphere has been largely overlooked. By transposing to the Archean nitrogen fluxes of modern topsoil communities known as biological soil crusts (terrestrial analogs of microbial mats), whose ancestors might have existed as far back as 3.2 Ga ago, we show that they could have impacted the evolution of the nitrogen cycle early on. We calculate that the net output of inorganic nitrogen reaching the Precambrian hydrogeological system could have been of the same order of magnitude as that of modern continents for a range of inhabited area as small as a few percent of that of present day continents. This contradicts the assumption that before the Great Oxidation Event, marine and continental biogeochemical nitrogen cycles were disconnected.
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Affiliation(s)
- Christophe Thomazo
- Biogéosciences UMR6282, CNRS, Univ. Bourgogne Franche-Comté, 21000, Dijon, France.
| | - Estelle Couradeau
- Biogéosciences UMR6282, CNRS, Univ. Bourgogne Franche-Comté, 21000, Dijon, France
- Center for Fundamental and Applied Microbiomics and School of Life Sciences, Arizona State University, 85282, Tempe, AZ, USA
| | - Ferran Garcia-Pichel
- Center for Fundamental and Applied Microbiomics and School of Life Sciences, Arizona State University, 85282, Tempe, AZ, USA
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9
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Mergelov N, Mueller CW, Prater I, Shorkunov I, Dolgikh A, Zazovskaya E, Shishkov V, Krupskaya V, Abrosimov K, Cherkinsky A, Goryachkin S. Alteration of rocks by endolithic organisms is one of the pathways for the beginning of soils on Earth. Sci Rep 2018; 8:3367. [PMID: 29463846 PMCID: PMC5820250 DOI: 10.1038/s41598-018-21682-6] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Accepted: 02/07/2018] [Indexed: 12/03/2022] Open
Abstract
Subaerial endolithic systems of the current extreme environments on Earth provide exclusive insight into emergence and development of soils in the Precambrian when due to various stresses on the surfaces of hard rocks the cryptic niches inside them were much more plausible habitats for organisms than epilithic ones. Using an actualistic approach we demonstrate that transformation of silicate rocks by endolithic organisms is one of the possible pathways for the beginning of soils on Earth. This process led to the formation of soil-like bodies on rocks in situ and contributed to the raise of complexity in subaerial geosystems. Endolithic systems of East Antarctica lack the noise from vascular plants and are among the best available natural models to explore organo-mineral interactions of a very old “phylogenetic age” (cyanobacteria-to-mineral, fungi-to-mineral, lichen-to-mineral). On the basis of our case study from East Antarctica we demonstrate that relatively simple endolithic systems of microbial and/or cryptogamic origin that exist and replicate on Earth over geological time scales employ the principles of organic matter stabilization strikingly similar to those known for modern full-scale soils of various climates.
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Affiliation(s)
- Nikita Mergelov
- Institute of Geography, Russian Academy of Sciences, Department of Soil Geography and Evolution, Moscow, 119017, Russia.
| | - Carsten W Mueller
- TU München, Lehrstuhl für Bodenkunde, Freising-Weihenstephan, 85354, Germany
| | - Isabel Prater
- TU München, Lehrstuhl für Bodenkunde, Freising-Weihenstephan, 85354, Germany
| | - Ilya Shorkunov
- Institute of Geography, Russian Academy of Sciences, Department of Soil Geography and Evolution, Moscow, 119017, Russia
| | - Andrey Dolgikh
- Institute of Geography, Russian Academy of Sciences, Department of Soil Geography and Evolution, Moscow, 119017, Russia
| | - Elya Zazovskaya
- Institute of Geography, Russian Academy of Sciences, Department of Soil Geography and Evolution, Moscow, 119017, Russia
| | - Vasily Shishkov
- Institute of Geography, Russian Academy of Sciences, Department of Soil Geography and Evolution, Moscow, 119017, Russia
| | - Victoria Krupskaya
- Institute of Geology of Ore Deposits, Petrography, Mineralogy and Geochemistry, Russian Academy of Sciences, Laboratory of Crystal Chemistry of Minerals, Moscow, 119017, Russia
| | - Konstantin Abrosimov
- V.V. Dokuchaev Soil Science Institute, Russian Academy of Sciences, Department of Soil Physics, Hydrology and Erosion, Moscow, 119017, Russia
| | - Alexander Cherkinsky
- Center for Applied Isotope Studies, University of Georgia, Athens, 30602, United States
| | - Sergey Goryachkin
- Institute of Geography, Russian Academy of Sciences, Department of Soil Geography and Evolution, Moscow, 119017, Russia
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10
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Stüeken EE, Buick R, Anderson RE, Baross JA, Planavsky NJ, Lyons TW. Environmental niches and metabolic diversity in Neoarchean lakes. GEOBIOLOGY 2017; 15:767-783. [PMID: 28856796 DOI: 10.1111/gbi.12251] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2017] [Accepted: 07/08/2017] [Indexed: 06/07/2023]
Abstract
The diversification of macro-organisms over the last 500 million years often coincided with the development of new environmental niches. Microbial diversification over the last 4 billion years likely followed similar patterns. However, linkages between environmental settings and microbial ecology have so far not been described from the ancient rock record. In this study, we investigated carbon, nitrogen, and molybdenum isotopes, and iron speciation in five non-marine stratigraphic units of the Neoarchean Fortescue Group, Western Australia, that are similar in age (2.78-2.72 Ga) but differ in their hydro-geologic setting. Our data suggest that the felsic-dominated and hydrologically open lakes of the Bellary and Hardey formations were probably dominated by methanogenesis (δ13 Corg = -38.7 ± 4.2‰) and biologic N2 fixation (δ15 Nbulk =-0.6 ± 1.0‰), whereas the Mt. Roe, Tumbiana and Kylena Formations, with more mafic siliciclastic sediments, preserve evidence of methanotrophy (δ13 Corg as low as -57.4‰, δ13 Ccarb as low as -9.2‰) and NH3 loss under alkaline conditions. Evidence of oxygenic photosynthesis is recorded only in the closed evaporitic Tumbiana lakes marked by abundant stromatolites, limited evidence of Fe and S cycling, fractionated Mo isotopes (δ98/95 Mo = +0.4 ± 0.4‰), and the widest range in δ13 Corg (-57‰ to -15‰), suggesting oxidative processes and multiple carbon fixation pathways. Methanotrophy in the three mafic settings was probably coupled to a combination of oxidants, including O2 and SO42- . Overall, our results may indicate that early microbial evolution on the Precambrian Earth was in part influenced by geological parameters. We speculate that expanding habitats, such as those linked to continental growth, may have been an important factor in the evolution of life.
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Affiliation(s)
- E E Stüeken
- School of Earth & Environmental Sciences, University of St Andrews, St Andrews, UK
- Virtual Planetary Laboratory, NASA Astrobiology Institute, University of Washington, Seattle, WA, USA
| | - R Buick
- Virtual Planetary Laboratory, NASA Astrobiology Institute, University of Washington, Seattle, WA, USA
- Department of Earth & Space Sciences, University of Washington, Seattle, WA, USA
| | - R E Anderson
- Virtual Planetary Laboratory, NASA Astrobiology Institute, University of Washington, Seattle, WA, USA
- Department of Biology, Carleton College, Northfield, MN, USA
| | - J A Baross
- Virtual Planetary Laboratory, NASA Astrobiology Institute, University of Washington, Seattle, WA, USA
- School of Oceanography, University of Washington, Seattle, WA, USA
| | - N J Planavsky
- Department of Geology and Geophysics, Yale University, New Haven, CT, USA
| | - T W Lyons
- Department of Earth Sciences, University of California, Riverside, CA, USA
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11
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Lenton TM, Daines SJ. Matworld - the biogeochemical effects of early life on land. THE NEW PHYTOLOGIST 2017; 215:531-537. [PMID: 27883194 DOI: 10.1111/nph.14338] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Accepted: 09/26/2016] [Indexed: 06/06/2023]
Abstract
Contents 531 I. 531 II. 532 III. 534 IV. 535 V. 535 VI. 535 Acknowledgements 536 References 536 SUMMARY: There is growing evidence that life has been on land for billions of years. Microbial mats fuelled by oxygenic photosynthesis were probably present in terrestrial habitats from c. 3.0 billion yr ago (Ga) onwards, creating localized 'oxygen oases' under a reducing atmosphere, which left a characteristic oxidative weathering signal. After the Great Oxidation c. 2.4 Ga, the now oxidizing atmosphere masked that redox signal, but ancient soils record the mobilization of phosphorus and other elements by organic acids in weathering profiles. Evidence for Neoproterozoic 'greening of the land' and intensification of weathering c. 0.85-0.54 Ga is currently equivocal. However, the mid-Palaeozoic c. 0.45-0.4 Ga shows global atmospheric changes consistent with increased terrestrial productivity and intensified weathering by the first land plants.
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Affiliation(s)
- Timothy M Lenton
- Earth System Science Group, College of Life and Environmental Sciences, University of Exeter, Exeter, EX4 4QE, UK
| | - Stuart J Daines
- Earth System Science Group, College of Life and Environmental Sciences, University of Exeter, Exeter, EX4 4QE, UK
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12
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Terrestrial Ecosystems in the Precambrian. BIOLOGICAL SOIL CRUSTS: AN ORGANIZING PRINCIPLE IN DRYLANDS 2016. [DOI: 10.1007/978-3-319-30214-0_3] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
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13
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Benthic perspective on Earth's oldest evidence for oxygenic photosynthesis. Proc Natl Acad Sci U S A 2015; 112:995-1000. [PMID: 25583484 DOI: 10.1073/pnas.1415718112] [Citation(s) in RCA: 149] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The Great Oxidation Event (GOE) is currently viewed as a protracted process during which atmospheric oxygen increased above ∼10(-5) times the present atmospheric level (PAL). This threshold represents an estimated upper limit for sulfur isotope mass-independent fractionation (S-MIF), an Archean signature of atmospheric anoxia that begins to disappear from the rock record at 2.45 Ga. However, an increasing number of papers have suggested that the timing for oxidative continental weathering, and by conventional thinking the onset of atmospheric oxygenation, was hundreds of million years earlier than previously thought despite the presence of S-MIF. We suggest that this apparent discrepancy can be resolved by the earliest oxidative-weathering reactions occurring in benthic and soil environments at profound redox disequilibrium with the atmosphere, such as biological soil crusts and freshwater microbial mats covering riverbed, lacustrine, and estuarine sediments. We calculate that oxygenic photosynthesis in these millimeter-thick ecosystems provides sufficient oxidizing equivalents to mobilize sulfate and redox-sensitive trace metals from land to the oceans while the atmosphere itself remained anoxic with its attendant S-MIF signature. As continental freeboard increased significantly between 3.0 and 2.5 Ga, the chemical and isotopic signatures of benthic oxidative weathering would have become more globally significant from a mass-balance perspective. These observations help reconcile evidence for pre-GOE oxidative weathering with the history of atmospheric chemistry, and support the plausible antiquity of a terrestrial biosphere populated by cyanobacteria well before the GOE.
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Mills DB, Canfield DE. Oxygen and animal evolution: did a rise of atmospheric oxygen "trigger" the origin of animals? Bioessays 2014; 36:1145-55. [PMID: 25244426 DOI: 10.1002/bies.201400101] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Recent studies challenge the classical view that the origin of animal life was primarily controlled by atmospheric oxygen levels. For example, some modern sponges, representing early-branching animals, can live under 200 times less oxygen than currently present in the atmosphere - levels commonly thought to have been maintained prior to their origination. Furthermore, it is increasingly argued that the earliest animals, which likely lived in low oxygen environments, played an active role in constructing the well-oxygenated conditions typical of the modern oceans. Therefore, while oxygen is still relevant to understanding early animal evolution, the relationships between the two might be less straightforward than previously thought.
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Affiliation(s)
- Daniel B Mills
- Department of Biology and the Nordic Center for Earth Evolution, University of Southern Denmark, Odense M, Denmark
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Voorhies AA, Biddanda BA, Kendall ST, Jain S, Marcus DN, Nold SC, Sheldon ND, Dick GJ. Cyanobacterial life at low O(2): community genomics and function reveal metabolic versatility and extremely low diversity in a Great Lakes sinkhole mat. GEOBIOLOGY 2012; 10:250-67. [PMID: 22404795 DOI: 10.1111/j.1472-4669.2012.00322.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Cyanobacteria are renowned as the mediators of Earth's oxygenation. However, little is known about the cyanobacterial communities that flourished under the low-O(2) conditions that characterized most of their evolutionary history. Microbial mats in the submerged Middle Island Sinkhole of Lake Huron provide opportunities to investigate cyanobacteria under such persistent low-O(2) conditions. Here, venting groundwater rich in sulfate and low in O(2) supports a unique benthic ecosystem of purple-colored cyanobacterial mats. Beneath the mat is a layer of carbonate that is enriched in calcite and to a lesser extent dolomite. In situ benthic metabolism chambers revealed that the mats are net sinks for O(2), suggesting primary production mechanisms other than oxygenic photosynthesis. Indeed, (14)C-bicarbonate uptake studies of autotrophic production show variable contributions from oxygenic and anoxygenic photosynthesis and chemosynthesis, presumably because of supply of sulfide. These results suggest the presence of either facultatively anoxygenic cyanobacteria or a mix of oxygenic/anoxygenic types of cyanobacteria. Shotgun metagenomic sequencing revealed a remarkably low-diversity mat community dominated by just one genotype most closely related to the cyanobacterium Phormidium autumnale, for which an essentially complete genome was reconstructed. Also recovered were partial genomes from a second genotype of Phormidium and several Oscillatoria. Despite the taxonomic simplicity, diverse cyanobacterial genes putatively involved in sulfur oxidation were identified, suggesting a diversity of sulfide physiologies. The dominant Phormidium genome reflects versatile metabolism and physiology that is specialized for a communal lifestyle under fluctuating redox conditions and light availability. Overall, this study provides genomic and physiologic insights into low-O(2) cyanobacterial mat ecosystems that played crucial geobiological roles over long stretches of Earth history.
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Affiliation(s)
- A A Voorhies
- Deptartment of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI, USA
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Beraldi-Campesi H, Hartnett HE, Anbar A, Gordon GW, Garcia-Pichel F. Effect of biological soil crusts on soil elemental concentrations: implications for biogeochemistry and as traceable biosignatures of ancient life on land. GEOBIOLOGY 2009; 7:348-359. [PMID: 19573165 DOI: 10.1111/j.1472-4669.2009.00204.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Biological soil crusts (BSCs) are topsoil biosedimentary structures built by photosynthetic microbes commonly found today on arid soils. They play a role in soil stabilization and the fertility of arid lands, and are considered modern analogues of ancient terrestrial microbial communities. We determined the concentrations of four biogenic and 21 other elements, mostly metals, in surface soils that hosted BSCs, in the soils underneath those crusts, and in proximate but non-crusted surface soils. The samples were from six sites in the Colorado Plateau highlands and the Sonoran Desert lowlands. In spite of the variability in climate and geologic setting, we found statistically significant overall trends of enrichment in biogenic elements and depletion in non-biogenic elements when BSCs were compared with non-crusted soils. The differences between crusted and non-crusted soils were statistically significant at approximately 95% confidence for C, N (enrichments) and for Ca, Cr, Mn, Cu, Zn, As, and Zr (depletions). These trends are best explained by the activity of microbes. As expected, no differences in the concentrations of C, N, P, and S were detected between the soils underneath the crusts and the non-crusted soils, but the former showed depletion of non-biogenic elements, indicating that the leaching effect of crust microbes extends downward in the soil. These patterns speak to the need for a sustained input of allochthonous material, possibly dust, to maintain BSC fertility. These elemental patterns can be considered a biosignature that may be preserved in the rock record and might help identify ancient microbial communities on land.
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Staples CR, Lahiri S, Raymond J, Von Herbulis L, Mukhophadhyay B, Blankenship RE. Expression and association of group IV nitrogenase NifD and NifH homologs in the non-nitrogen-fixing archaeon Methanocaldococcus jannaschii. J Bacteriol 2007; 189:7392-8. [PMID: 17660283 PMCID: PMC2168459 DOI: 10.1128/jb.00876-07] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Using genomic analysis, researchers previously identified genes coding for proteins homologous to the structural proteins of nitrogenase (J. Raymond, J. L. Siefert, C. R. Staples, and R. E. Blankenship, Mol. Biol. Evol. 21:541-554, 2004). The expression and association of NifD and NifH nitrogenase homologs (named NflD and NflH for "Nif-like" D and H, respectively) have been detected in a non-nitrogen-fixing hyperthermophilic methanogen, Methanocaldococcus jannaschii. These homologs are expressed constitutively and do not appear to be directly involved with nitrogen metabolism or detoxification of compounds such as cyanide or azide. The NflH and NflD proteins were found to interact with each other, as determined by bacterial two-hybrid studies. Upon immunoisolation, NflD and NflH copurified, along with three other proteins whose functions are as yet uncharacterized. The apparent presence of genes coding for NflH and NflD in all known methanogens, their constitutive expression, and their high sequence similarity to the NifH and NifD proteins or the BchL and BchN/BchB proteins suggest that NflH and NflD participate in an indispensable and fundamental function(s) in methanogens.
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Hausrath EM, Liermann LJ, House CH, Ferry JG, Brantley SL. The effect of methanogen growth on mineral substrates: will Ni markers of methanogen-based communities be detectable in the rock record? GEOBIOLOGY 2007; 5:49-61. [PMID: 36298875 DOI: 10.1111/j.1472-4669.2007.00095.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Methanogens, thought to be present on early Earth, have a high requirement for Ni, suggesting that Ni utilization could be a potential biosignature for methanogens if enhanced Ni extraction from surrounding minerals accompanies methanogenic growth. To test the potential for such Ni extraction from minerals by methanogens, Ni release from Ni-containing silicate glass was measured in Ni-free growth medium in the presence of the methanogen Methanothermobacter thermoautotrophicus (average pH ∼7.0) and observed to be higher than an abiotic control (average pH ∼6.8). However, batch dissolution experiments and a siderophore assay indicate that cell exudates such as siderophores, low molecular weight organic acids, or lysates accompanying cell death are not responsible for the observed increase in Ni release rate. In addition, scanning electron microscopy (SEM) shows little to no evidence of direct microbe-mineral interactions such as biofilms or pitting. Instead, comparison with abiotic experiments suggests that changes in pH due to CO2 uptake may be responsible for enhanced dissolution in the presence of metabolizing cells. These results document that methanogens may not preferentially extract Ni from surrounding minerals although they may indirectly affect mineral reaction rates that are pH sensitive. Thus identifiable Ni biosignatures may not exist in the rock record to document the presence of methanogens on early Earth or Mars.
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Affiliation(s)
- Elizabeth M Hausrath
- Department of Geosciences, The Pennsylvania State University, University Park, PA 16802, USA
| | - Laura J Liermann
- Department of Geosciences, The Pennsylvania State University, University Park, PA 16802, USA
| | - Christopher H House
- Department of Geosciences, The Pennsylvania State University, University Park, PA 16802, USA
| | - James G Ferry
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA
| | - Susan L Brantley
- Department of Geosciences, The Pennsylvania State University, University Park, PA 16802, USA
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Hessler AM, Lowe DR, Jones RL, Bird DK. A lower limit for atmospheric carbon dioxide levels 3.2 billion years ago. Nature 2004; 428:736-8. [PMID: 15085128 DOI: 10.1038/nature02471] [Citation(s) in RCA: 105] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2003] [Accepted: 03/09/2004] [Indexed: 11/08/2022]
Abstract
The quantification of greenhouse gases present in the Archaean atmosphere is critical for understanding the evolution of atmospheric oxygen, surface temperatures and the conditions for life on early Earth. For instance, it has been argued that small changes in the balance between two potential greenhouse gases, carbon dioxide and methane, may have dictated the feedback cycle involving organic haze production and global cooling. Climate models have focused on carbon dioxide as the greenhouse gas responsible for maintaining above-freezing surface temperatures during a time of low solar luminosity. However, the analysis of 2.75-billion-year (Gyr)-old palaeosols--soil samples preserved in the geologic record--have recently provided an upper constraint on atmospheric carbon dioxide levels well below that required in most climate models to prevent the Earth's surface from freezing. This finding prompted many to look towards methane as an additional greenhouse gas to satisfy climate models. Here we use model equilibrium reactions for weathering rinds on 3.2-Gyr-old river gravels to show that the presence of iron-rich carbonate relative to common clay minerals requires a minimum partial pressure of carbon dioxide several times higher than present-day values. Unless actual carbon dioxide levels were considerably greater than this, climate models predict that additional greenhouse gases would still need to have a role in maintaining above-freezing surface temperatures.
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Affiliation(s)
- Angela M Hessler
- Department of Geological and Environmental Sciences, Stanford University, Stanford, California 94305-2115, USA.
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Catling DC, Zahnle KJ, McKay C. Biogenic methane, hydrogen escape, and the irreversible oxidation of early Earth. Science 2001; 293:839-43. [PMID: 11486082 DOI: 10.1126/science.1061976] [Citation(s) in RCA: 350] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The low O2 content of the Archean atmosphere implies that methane should have been present at levels approximately 10(2) to 10(3) parts per million volume (ppmv) (compared with 1.7 ppmv today) given a plausible biogenic source. CH4 is favored as the greenhouse gas that countered the lower luminosity of the early Sun. But abundant CH4 implies that hydrogen escapes to space (upward arrow space) orders of magnitude faster than today. Such reductant loss oxidizes the Earth. Photosynthesis splits water into O2 and H, and methanogenesis transfers the H into CH4. Hydrogen escape after CH4 photolysis, therefore, causes a net gain of oxygen [CO2 + 2H2O --> CH4 + 2O2 --> CO2 + O2 + 4H(upward arrow space)]. Expected irreversible oxidation (approximately 10(12) to 10(13) moles oxygen per year) may help explain how Earth's surface environment became irreversibly oxidized.
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Affiliation(s)
- D C Catling
- Mail Stop 245-3, Space Science Division, NASA Ames Research Center, Moffett Field, CA 94035, USA.
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