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Boag TH, Busch JF, Gooley JT, Strauss JV, Sperling EA. Deep-water first occurrences of Ediacara biota prior to the Shuram carbon isotope excursion in the Wernecke Mountains, Yukon, Canada. GEOBIOLOGY 2024; 22:e12597. [PMID: 38700422 DOI: 10.1111/gbi.12597] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Revised: 02/29/2024] [Accepted: 03/27/2024] [Indexed: 05/05/2024]
Abstract
Ediacara-type macrofossils appear as early as ~575 Ma in deep-water facies of the Drook Formation of the Avalon Peninsula, Newfoundland, and the Nadaleen Formation of Yukon and Northwest Territories, Canada. Our ability to assess whether a deep-water origination of the Ediacara biota is a genuine reflection of evolutionary succession, an artifact of an incomplete stratigraphic record, or a bathymetrically controlled biotope is limited by a lack of geochronological constraints and detailed shelf-to-slope transects of Ediacaran continental margins. The Ediacaran Rackla Group of the Wernecke Mountains, NW Canada, represents an ideal shelf-to-slope depositional system to understand the spatiotemporal and environmental context of Ediacara-type organisms' stratigraphic occurrence. New sedimentological and paleontological data presented herein from the Wernecke Mountains establish a stratigraphic framework relating shelfal strata in the Goz/Corn Creek area to lower slope deposits in the Nadaleen River area. We report new discoveries of numerous Aspidella hold-fast discs, indicative of frondose Ediacara organisms, from deep-water slope deposits of the Nadaleen Formation stratigraphically below the Shuram carbon isotope excursion (CIE) in the Nadaleen River area. Such fossils are notably absent in coeval shallow-water strata in the Goz/Corn Creek region despite appropriate facies for potential preservation. The presence of pre-Shuram CIE Ediacara-type fossils occurring only in deep-water facies within a basin that has equivalent well-preserved shallow-water facies provides the first stratigraphic paleobiological support for a deep-water origination of the Ediacara biota. In contrast, new occurrences of Ediacara-type fossils (including juvenile fronds, Beltanelliformis, Aspidella, annulated tubes, and multiple ichnotaxa) are found above the Shuram CIE in both deep- and shallow-water deposits of the Blueflower Formation. Given existing age constraints on the Shuram CIE, it appears that Ediacaran organisms may have originated in the deeper ocean and lived there for up to ~15 million years before migrating into shelfal environments in the terminal Ediacaran. This indicates unique ecophysiological constraints likely shaped the initial habitat preference and later environmental expansion of the Ediacara biota.
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Affiliation(s)
- Thomas H Boag
- Department of Earth and Planetary Science, Stanford University, Stanford, California, USA
- Department of Earth and Planetary Sciences, Yale University, New Haven, Connecticut, USA
- Department of Geosciences, Princeton University, Princeton, New Jersey, USA
| | - James F Busch
- Department of Earth Sciences, Dartmouth College, Hanover, New Hampshire, USA
| | - Jared T Gooley
- Alaska Science Center, U.S. Geological Survey, Anchorage, Alaska, USA
| | - Justin V Strauss
- Department of Earth Sciences, Dartmouth College, Hanover, New Hampshire, USA
| | - Erik A Sperling
- Department of Earth and Planetary Science, Stanford University, Stanford, California, USA
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2
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Watanabe Y, Tajika E, Ozaki K. Evolution of iron and oxygen biogeochemical cycles during the Precambrian. GEOBIOLOGY 2023; 21:689-707. [PMID: 37622474 DOI: 10.1111/gbi.12571] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Revised: 07/05/2023] [Accepted: 08/12/2023] [Indexed: 08/26/2023]
Abstract
Iron (Fe) is an essential element for life, and its geochemical cycle is intimately linked to the coupled history of life and Earth's environment. The accumulated geologic records indicate that ferruginous waters existed in the Precambrian oceans not only before the first major rise of atmospheric O2 levels (Great Oxidation Event; GOE) during the Paleoproterozoic, but also during the rest of the Proterozoic. However, the interactive evolution of the biogeochemical cycles of O2 and Fe during the Archean-Proterozoic remains ambiguous. Here, we develop a biogeochemical model to investigate the coupled biogeochemical evolution of Fe-O2 -P-C cycles across the GOE. Our model demonstrates that the marine Fe cycle was less sensitive to changes in the production rate of O2 before the GOE (atmospheric pO2 < 10-6 PAL; present atmospheric level). When the P supply rate to the ocean exceeds a certain threshold, the GOE occurs and atmospheric pO2 rises to ~10-3 -10-1 PAL. After the GOE, the marine Fe(II) concentration is highly sensitive to atmospheric pO2 , suggesting that the marine redox landscape during the Proterozoic may have fluctuated between ferruginous conditions and anoxic non-ferruginous conditions with sulfidic water masses around continental margins. At a certain threshold value of atmospheric pO2 of ~0.3% PAL, the primary oxidation pathway of Fe(II) shifts from the activity of Fe(II)-utilizing anoxygenic photoautotrophs in sunlit surface waters to abiotic process in the deep ocean. This is accompanied by a shift in the primary deposition site of Fe(III) hydroxides from the surface ocean to the deep sea, providing a plausible mechanistic explanation for the observed cessation of iron formations during the Proterozoic.
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Affiliation(s)
- Yasuto Watanabe
- Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Eiichi Tajika
- Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Kazumi Ozaki
- Department of Earth and Planetary Sciences, Tokyo Institute of Technology, Tokyo, Japan
- Earth-Life Science Institute, Tokyo Institute of Technology, Tokyo, Japan
- Alternative Earths Team, Interdisciplinary Consortia for Astrobiology Research, National Aeronautics and Space Administration, Riverside, California, USA
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3
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Hou Z, Zhou Q, Xie Y, Mo F, Kang W, Wang Q. Potential contribution of chlorella vulgaris to carbon-nitrogen turnover in freshwater ecosystems after a great sandstorm event. ENVIRONMENTAL RESEARCH 2023; 234:116569. [PMID: 37422116 DOI: 10.1016/j.envres.2023.116569] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 06/30/2023] [Accepted: 07/05/2023] [Indexed: 07/10/2023]
Abstract
Urban lakes represent important land-water and nature-human dual interfaces that promote the cycling of elements from terrestrials to sediments and consequently modulating the stabilization of regional climate. However, whether disturbances caused by extreme weather events can have substantial effects on carbon-nitrogen (C-N) cycling in these ecosystems are vague. To explore the impact of phytoplankton on the ecological retention time of C-N, two kinds of freshwater (natural and landscape) were collected and conducted a microcosm experiment using a freshwater algal species Chlorella vulgaris. Sandstorm events increased dissolved inorganic carbon in freshwater (65.55 ± 3.09 and 39.46 ± 2.51 mg·L-1 for samples from Jinyang and Nankai, respectively) and significantly affected the relevant pathways of photosynthesis in Chlorella vulgaris, including enhancing chlorophyll fluorescence (The effective quantum yield of PSII at the fifth day of incubation was 0.34 and 0.35 for Nankai and Jinyang, respectively), promoting the synthesis of sugars and inhibiting the synthesis of glycine and serine related proteins. Besides, carbon from plant biomass accumulation and cellular metabolism (fulvic acid-like, polyaromatic-type humic acid and polycarboxylate-type humic acid, etc.) was enriched into residues and become a kind of energy source for the decomposer (TC mass increased by 1.63-2.13 times after 21 days of incubation). This means that the accumulation and consumption of carbon and nitrogen in the residue can be used to track the processes controlling the long-term C-N cycle. Our findings shed light on the plant residues were key factors contributing to the formation of water carbon pool, breaks the traditional theory that dissolved carbonates cannot produce carbon sinks.
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Affiliation(s)
- Zelin Hou
- MOE Key Laboratory of Pollution Processes and Environmental Criteria/Tianjin Key Laboratory of Environmental Remediation and Pollution Control, Carbon Neutrality Science Center, College of Environmental Science and Engineering, Nankai University, Tianjin, 300350, China
| | - Qixing Zhou
- MOE Key Laboratory of Pollution Processes and Environmental Criteria/Tianjin Key Laboratory of Environmental Remediation and Pollution Control, Carbon Neutrality Science Center, College of Environmental Science and Engineering, Nankai University, Tianjin, 300350, China.
| | - Yingying Xie
- MOE Key Laboratory of Pollution Processes and Environmental Criteria/Tianjin Key Laboratory of Environmental Remediation and Pollution Control, Carbon Neutrality Science Center, College of Environmental Science and Engineering, Nankai University, Tianjin, 300350, China
| | - Fan Mo
- MOE Key Laboratory of Pollution Processes and Environmental Criteria/Tianjin Key Laboratory of Environmental Remediation and Pollution Control, Carbon Neutrality Science Center, College of Environmental Science and Engineering, Nankai University, Tianjin, 300350, China
| | - Weilu Kang
- MOE Key Laboratory of Pollution Processes and Environmental Criteria/Tianjin Key Laboratory of Environmental Remediation and Pollution Control, Carbon Neutrality Science Center, College of Environmental Science and Engineering, Nankai University, Tianjin, 300350, China
| | - Qi Wang
- MOE Key Laboratory of Pollution Processes and Environmental Criteria/Tianjin Key Laboratory of Environmental Remediation and Pollution Control, Carbon Neutrality Science Center, College of Environmental Science and Engineering, Nankai University, Tianjin, 300350, China
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4
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Hou Z, Ma X, Shi X, Li X, Yang L, Xiao S, De Clerck O, Leliaert F, Zhong B. Phylotranscriptomic insights into a Mesoproterozoic-Neoproterozoic origin and early radiation of green seaweeds (Ulvophyceae). Nat Commun 2022; 13:1610. [PMID: 35318329 PMCID: PMC8941102 DOI: 10.1038/s41467-022-29282-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Accepted: 03/09/2022] [Indexed: 01/09/2023] Open
Abstract
The Ulvophyceae, a major group of green algae, is of particular evolutionary interest because of its remarkable morphological and ecological diversity. Its phylogenetic relationships and diversification timeline, however, are still not fully resolved. In this study, using an extensive nuclear gene dataset, we apply coalescent- and concatenation-based approaches to reconstruct the phylogeny of the Ulvophyceae and to explore the sources of conflict in previous phylogenomic studies. The Ulvophyceae is recovered as a paraphyletic group, with the Bryopsidales being a sister group to the Chlorophyceae, and the remaining taxa forming a clade (Ulvophyceae sensu stricto). Molecular clock analyses with different calibration strategies emphasize the large impact of fossil calibrations, and indicate a Meso-Neoproterozoic origin of the Ulvophyceae (sensu stricto), earlier than previous estimates. The results imply that ulvophyceans may have had a profound influence on oceanic redox structures and global biogeochemical cycles at the Mesoproterozoic-Neoproterozoic transition. “Ulvophyceae is a remarkably morphologically and ecologically diverse clade of green algae. Here, the authors reconstruct the Ulvophyceae phylogeny, showing that these algae originated earlier than expected and may have influenced biogeochemical cycles at the Mesoproterozoic-Neoproterozoic transition.”
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Affiliation(s)
- Zheng Hou
- College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Xiaoya Ma
- College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Xuan Shi
- College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Xi Li
- College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Lingxiao Yang
- College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Shuhai Xiao
- Department of Geosciences and Global Change Center, Virginia Tech, Blacksburg, VA, USA
| | - Olivier De Clerck
- Phycology Research Group and Center for Molecular Phylogenetics and Evolution, Ghent University, Ghent, Belgium
| | - Frederik Leliaert
- Phycology Research Group and Center for Molecular Phylogenetics and Evolution, Ghent University, Ghent, Belgium.,Meise Botanic Garden, Meise, Belgium
| | - Bojian Zhong
- College of Life Sciences, Nanjing Normal University, Nanjing, China.
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5
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Abstract
The large-scale dynamics of ocean oxygenation have changed dramatically throughout Earth's history, in step with major changes in the abundance of O2 in the atmosphere and changes to marine nutrient availability. A comprehensive mechanistic understanding of this history requires insights from oceanography, marine geology, geochemistry, geomicrobiology, evolutionary ecology, and Earth system modeling. Here, we attempt to synthesize the major features of evolving ocean oxygenation on Earth through more than 3 billion years of planetary history. We review the fundamental first-order controls on ocean oxygen distribution and summarize the current understanding of the history of ocean oxygenation on Earth from empirical and theoretical perspectives-integrating geochemical reconstructions of oceanic and atmospheric chemistry, genomic constraints on evolving microbial metabolism, and mechanistic biogeochemical models. These changes are used to illustrate primary regimes of large-scale ocean oxygenation and to highlight feedbacks that can act to stabilize and destabilize the ocean-atmosphere system in anoxic, low-oxygen, and high-oxygen states.
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Affiliation(s)
- Christopher T Reinhard
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, Georgia 30332, USA;
- Alternative Earths Team, Interdisciplinary Consortia for Astrobiology Research, National Aeronautics and Space Administration, Riverside, California 92521, USA
- Nexus for Exoplanet System Science (NExSS), National Aeronautics and Space Administration, Washington, DC 20546, USA
| | - Noah J Planavsky
- Alternative Earths Team, Interdisciplinary Consortia for Astrobiology Research, National Aeronautics and Space Administration, Riverside, California 92521, USA
- Department of Earth and Planetary Sciences, Yale University, New Haven, Connecticut 06511, USA
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6
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Lyons TW, Diamond CW, Planavsky NJ, Reinhard CT, Li C. Oxygenation, Life, and the Planetary System during Earth's Middle History: An Overview. ASTROBIOLOGY 2021; 21:906-923. [PMID: 34314605 PMCID: PMC8403206 DOI: 10.1089/ast.2020.2418] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
The long history of life on Earth has unfolded as a cause-and-effect relationship with the evolving amount of oxygen (O2) in the oceans and atmosphere. Oxygen deficiency characterized our planet's first 2 billion years, yet evidence for biological O2 production and local enrichments in the surface ocean appear long before the first accumulations of O2 in the atmosphere roughly 2.4 to 2.3 billion years ago. Much has been written about this fundamental transition and the related balance between biological O2 production and sinks coupled to deep Earth processes that could buffer against the accumulation of biogenic O2. However, the relationship between complex life (eukaryotes, including animals) and later oxygenation is less clear. Some data suggest O2 was higher but still mostly low for another billion and a half years before increasing again around 800 million years ago, potentially setting a challenging course for complex life during its initial development and ecological expansion. The apparent rise in O2 around 800 million years ago is coincident with major developments in complex life. Multiple geochemical and paleontological records point to a major biogeochemical transition at that time, but whether rising and still dynamic biospheric oxygen triggered or merely followed from innovations in eukaryotic ecology, including the emergence of animals, is still debated. This paper focuses on the geochemical records of Earth's middle history, roughly 1.8 to 0.5 billion years ago, as a backdrop for exploring possible cause-and-effect relationships with biological evolution and the primary controls that may have set its pace, including solid Earth/tectonic processes, nutrient limitation, and their possible linkages. A richer mechanistic understanding of the interplay between coevolving life and Earth surface environments can provide a template for understanding and remotely searching for sustained habitability and even life on distant exoplanets.
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Affiliation(s)
- Timothy W. Lyons
- Department of Earth and Planetary Sciences, University of California, Riverside, California, USA
- Address correspondence to: Timothy W. Lyons, Department of Earth and Planetary Sciences, University of California, Riverside, CA 92521, USA
| | - Charles W. Diamond
- Department of Earth and Planetary Sciences, University of California, Riverside, California, USA
| | - Noah J. Planavsky
- Department of Earth and Planetary Sciences, Yale University, New Haven, Connecticut, USA
| | - Christopher T. Reinhard
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Chao Li
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, China
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7
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Rivera-Valentín EG, Filiberto J, Lynch KL, Mamajanov I, Lyons TW, Schulte M, Méndez A. Introduction-First Billion Years: Habitability. ASTROBIOLOGY 2021; 21:893-905. [PMID: 34406807 PMCID: PMC8403211 DOI: 10.1089/ast.2020.2314] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 12/22/2020] [Indexed: 06/13/2023]
Abstract
The physical processes active during the first billion years (FBY) of Earth's history, such as accretion, differentiation, and impact cratering, provide constraints on the initial conditions that were conducive to the formation and establishment of life on Earth. This motivated the Lunar and Planetary Institute's FBY topical initiative, which was a four-part conference series intended to look at each of these physical processes to study the basic structure and composition of our Solar System that was set during the FBY. The FBY Habitability conference, held in September 2019, was the last in this series and was intended to synthesize the initiative; specifically, to further our understanding of the origins of life, planetary and environmental habitability, and the search for life beyond Earth. The conference included discussions of planetary habitability and the potential emergence of life on bodies within our Solar System, as well as extrasolar systems by applying our knowledge of the Solar System's FBY, and in particular Earth's early history. To introduce this Special Collection, which resulted from work discussed at the conference, we provide a review of the main themes and a synopsis of the FBY Habitability conference.
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Affiliation(s)
| | - Justin Filiberto
- Lunar and Planetary Institute, Universities Space Research Association, Houston, Texas, USA
| | - Kennda L. Lynch
- Lunar and Planetary Institute, Universities Space Research Association, Houston, Texas, USA
| | - Irena Mamajanov
- Earth-Life Science Institute, Tokyo Institute of Technology, Tokyo, Japan
| | - Timothy W. Lyons
- Department of Earth and Planetary Sciences, University of California Riverside, Riverside, California, USA
| | - Mitch Schulte
- Planetary Science Division, NASA Headquarters, Washington, District of Columbia, USA
| | - Abel Méndez
- Planetary Habitability Laboratory, University of Puerto Rico Arecibo, Arecibo, Puerto Rico
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8
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Sperling EA, Melchin MJ, Fraser T, Stockey RG, Farrell UC, Bhajan L, Brunoir TN, Cole DB, Gill BC, Lenz A, Loydell DK, Malinowski J, Miller AJ, Plaza-Torres S, Bock B, Rooney AD, Tecklenburg SA, Vogel JM, Planavsky NJ, Strauss JV. A long-term record of early to mid-Paleozoic marine redox change. SCIENCE ADVANCES 2021; 7:7/28/eabf4382. [PMID: 34233874 PMCID: PMC8262801 DOI: 10.1126/sciadv.abf4382] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Accepted: 05/25/2021] [Indexed: 05/03/2023]
Abstract
The extent to which Paleozoic oceans differed from Neoproterozoic oceans and the causal relationship between biological evolution and changing environmental conditions are heavily debated. Here, we report a nearly continuous record of seafloor redox change from the deep-water upper Cambrian to Middle Devonian Road River Group of Yukon, Canada. Bottom waters were largely anoxic in the Richardson trough during the entirety of Road River Group deposition, while independent evidence from iron speciation and Mo/U ratios show that the biogeochemical nature of anoxia changed through time. Both in Yukon and globally, Ordovician through Early Devonian anoxic waters were broadly ferruginous (nonsulfidic), with a transition toward more euxinic (sulfidic) conditions in the mid-Early Devonian (Pragian), coincident with the early diversification of vascular plants and disappearance of graptolites. This ~80-million-year interval of the Paleozoic characterized by widespread ferruginous bottom waters represents a persistence of Neoproterozoic-like marine redox conditions well into the Phanerozoic.
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Affiliation(s)
- Erik A Sperling
- Department of Geological Sciences, Stanford University, Stanford, CA, USA.
| | - Michael J Melchin
- Department of Earth Sciences, St. Francis Xavier University, Antigonish, Nova Scotia, Canada
| | | | - Richard G Stockey
- Department of Geological Sciences, Stanford University, Stanford, CA, USA
| | - Una C Farrell
- Department of Geological Sciences, Stanford University, Stanford, CA, USA
- Department of Geology, Trinity College Dublin, Dublin 2, Ireland
| | - Liam Bhajan
- Department of Geological Sciences, Stanford University, Stanford, CA, USA
| | - Tessa N Brunoir
- Department of Geological Sciences, Stanford University, Stanford, CA, USA
| | - Devon B Cole
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - Benjamin C Gill
- Department of Geosciences, Virginia Polytechnic University and State University, Blacksburg, VA, USA
| | - Alfred Lenz
- Department of Earth Sciences, Western University Canada, London, ON, Canada
| | - David K Loydell
- School of the Environment, Geography and Geosciences, University of Portsmouth, Portsmouth, UK
| | | | - Austin J Miller
- Department of Geological Sciences, Stanford University, Stanford, CA, USA
| | | | - Beatrice Bock
- Department of Earth and Environmental Sciences, Vanderbilt University, Nashville, TN, USA
| | - Alan D Rooney
- Department of Earth and Planetary Sciences, Yale University, New Haven, CT, USA
| | | | - Jacqueline M Vogel
- Department of Geological Sciences, Stanford University, Stanford, CA, USA
| | - Noah J Planavsky
- Department of Earth and Planetary Sciences, Yale University, New Haven, CT, USA
| | - Justin V Strauss
- Department of Earth Sciences, Dartmouth College, Hanover, NH, USA.
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9
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Abstract
Changes in ocean redox chemistry are frequently observed in Earth’s history and have fundamental implications for the evolution of marine life. These transitions are commonly ascribed to large changes in the supply of iron, sulfur, or organic carbon in the deeper ocean. We propose that small variations in carbon input flux can drive nonreversible redox changes of the ocean interior and other anoxic systems, such as marine sediments. Nonlinear interactions in the iron and sulfur cycles create tipping points where regime shifts can occur between alternative stable states that are either iron dominated or sulfide dominated. The recognition that the biogeochemistry of sediments and oceans embeds intrinsic bistability provides a conceptual framework for understanding past and present anoxic marine systems. For most of Earth’s history, the ocean’s interior was pervasively anoxic and showed occasional shifts in ocean redox chemistry between iron-buffered and sulfide-buffered states. These redox transitions are most often explained by large changes in external inputs, such as a strongly altered delivery of iron and sulfate to the ocean, or major shifts in marine productivity. Here, we propose that redox shifts can also arise from small perturbations that are amplified by nonlinear positive feedbacks within the internal iron and sulfur cycling of the ocean. Combining observational evidence with biogeochemical modeling, we show that both sedimentary and aquatic systems display intrinsic iron–sulfur bistability, which is tightly linked to the formation of reduced iron–sulfide minerals. The possibility of tipping points in the redox state of sediments and oceans, which allow large and nonreversible geochemical shifts to arise from relatively small changes in organic carbon input, has important implications for the interpretation of the geological rock record and the causes and consequences of major evolutionary transitions in the history of Earth’s biosphere.
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10
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Lenton TM. On the use of models in understanding the rise of complex life. Interface Focus 2020; 10:20200018. [PMID: 32642056 PMCID: PMC7333900 DOI: 10.1098/rsfs.2020.0018] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/07/2020] [Indexed: 11/12/2022] Open
Abstract
Recently, several seemingly irreconcilably different models have been proposed for relationships between Earth system processes and the rise of complex life. These models provide very different scenarios of Proterozoic atmospheric oxygen and ocean nutrient levels, whether they constrained complex life, and of how the rise of complex life affected biogeochemical conditions. For non-modellers, it can be hard to evaluate which-if any-of the models and their results have more credence-hence this article. I briefly review relevant hypotheses, how models are being used to incarnate and sometimes test those hypotheses, and key principles of biogeochemical cycling models should embody. Then I critically review the use of biogeochemical models in: inferring key variables from proxies; reconstructing ancient biogeochemical cycling; and examining how complex life affected biogeochemical cycling. Problems are found in published model results purporting to demonstrate long-term stable states of very low Proterozoic atmospheric pO2 and ocean P levels. I explain what they stem from and highlight key empirical uncertainties that need to be resolved. Then I suggest how models and data can be better combined to advance our scientific understanding of the relationship between Earth system processes and the rise of complex life.
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11
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12
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Planavsky NJ, Reinhard CT, Isson TT, Ozaki K, Crockford PW. Large Mass-Independent Oxygen Isotope Fractionations in Mid-Proterozoic Sediments: Evidence for a Low-Oxygen Atmosphere? ASTROBIOLOGY 2020; 20:628-636. [PMID: 32228301 DOI: 10.1089/ast.2019.2060] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Earth's ocean-atmosphere system has undergone a dramatic but protracted increase in oxygen (O2) abundance. This environmental transition ultimately paved the way for the rise of multicellular life and provides a blueprint for how a biosphere can transform a planetary surface. However, estimates of atmospheric oxygen levels for large intervals of Earth's history still vary by orders of magnitude-foremost for Earth's middle history. Historically, estimates of mid-Proterozoic (1.9-0.8 Ga) atmospheric oxygen levels are inferred based on the kinetics of reactions occurring in soils or in the oceans, rather than being directly tracked by atmospheric signatures. Rare oxygen isotope systematics-based on quantifying the rare oxygen isotope 17O in addition to the conventionally determined 16O and 18O-provide a means to track atmospheric isotopic signatures and thus potentially provide more direct estimates of atmospheric oxygen levels through time. Oxygen isotope signatures that deviate strongly from the expected mass-dependent relationship between 16O, 17O, and 18O develop during ozone formation, and these "mass-independent" signals can be transferred to the rock record during oxidation reactions in surface environments that involve atmospheric O2. The magnitude of these signals is dependent upon pO2, pCO2, and the overall extent of biospheric productivity. Here, we use a stochastic approach to invert the mid-Proterozoic Δ17O record for a new estimate of atmospheric pO2, leveraging explicit coupling of pO2 and biospheric productivity in a biogeochemical Earth system model to refine the range of atmospheric pO2 values that is consistent with a given observed Δ17O. Using this approach, we find new evidence that atmospheric oxygen levels were less than ∼1% of the present atmospheric level (PAL) for at least some intervals of the Proterozoic Eon.
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Affiliation(s)
- Noah J Planavsky
- Department of Geology and Geophysics, Yale University, New Haven, Connecticut, USA
| | - Christopher T Reinhard
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Terry T Isson
- Environmental Research Institute, University of Waikato, Tauranga, New Zealand
| | - Kazumi Ozaki
- Department of Environmental Science, Toho University, Funabashi, Chiba, Japan
| | - Peter W Crockford
- Department of Earth and Planetary Sciences, Weizmann Institute of Science, Rehovot, Israel
- Department of Geosciences, Princeton University, Princeton, New Jersey, USA
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13
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Cole DB, Mills DB, Erwin DH, Sperling EA, Porter SM, Reinhard CT, Planavsky NJ. On the co-evolution of surface oxygen levels and animals. GEOBIOLOGY 2020; 18:260-281. [PMID: 32175670 DOI: 10.1111/gbi.12382] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 01/04/2020] [Accepted: 01/22/2020] [Indexed: 05/22/2023]
Abstract
Few topics in geobiology have been as extensively debated as the role of Earth's oxygenation in controlling when and why animals emerged and diversified. All currently described animals require oxygen for at least a portion of their life cycle. Therefore, the transition to an oxygenated planet was a prerequisite for the emergence of animals. Yet, our understanding of Earth's oxygenation and the environmental requirements of animal habitability and ecological success is currently limited; estimates for the timing of the appearance of environments sufficiently oxygenated to support ecologically stable populations of animals span a wide range, from billions of years to only a few million years before animals appear in the fossil record. In this light, the extent to which oxygen played an important role in controlling when animals appeared remains a topic of debate. When animals originated and when they diversified are separate questions, meaning either one or both of these phenomena could have been decoupled from oxygenation. Here, we present views from across this interpretive spectrum-in a point-counterpoint format-regarding crucial aspects of the potential links between animals and surface oxygen levels. We highlight areas where the standard discourse on this topic requires a change of course and note that several traditional arguments in this "life versus environment" debate are poorly founded. We also identify a clear need for basic research across a range of fields to disentangle the relationships between oxygen availability and emergence and diversification of animal life.
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Affiliation(s)
- Devon B Cole
- School of Earth and Atmospheric Science, Georgia Institute of Technology, Atlanta, Georgia
| | - Daniel B Mills
- Department of Geological Sciences, Stanford University, Stanford, California
| | - Douglas H Erwin
- Department of Paleobiology, National Museum of Natural History, Washington, District of Columbia
- Santa Fe Institute, Santa Fe, New Mexico
| | - Erik A Sperling
- Department of Geological Sciences, Stanford University, Stanford, California
| | - Susannah M Porter
- Department of Earth Science, University of California Santa Barbara, Santa Barbara, California
| | - Christopher T Reinhard
- School of Earth and Atmospheric Science, Georgia Institute of Technology, Atlanta, Georgia
| | - Noah J Planavsky
- Department of Geology and Geophysics, Yale University, New Haven, Connecticut
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Zumberge JA, Rocher D, Love GD. Free and kerogen-bound biomarkers from late Tonian sedimentary rocks record abundant eukaryotes in mid-Neoproterozoic marine communities. GEOBIOLOGY 2020; 18:326-347. [PMID: 31865640 PMCID: PMC7233469 DOI: 10.1111/gbi.12378] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Revised: 10/31/2019] [Accepted: 11/30/2019] [Indexed: 05/23/2023]
Abstract
Lipid biomarker assemblages preserved within the bitumen and kerogen phases of sedimentary rocks from the ca. 780-729 Ma Chuar and Visingsö Groups facilitate paleoenvironmental reconstructions and reveal fundamental aspects of emerging mid-Neoproterozoic marine communities. The Chuar and Visingsö Groups were deposited offshore of two distinct paleocontinents (Laurentia and Baltica, respectively) during the Tonian Period, and the rock samples used had not undergone excessive metamorphism. The major polycyclic alkane biomarkers detected in the rock bitumens and kerogen hydropyrolysates consist of tricyclic terpanes, hopanes, methylhopanes, and steranes. Major features of the biomarker assemblages include detectable and significant contribution from eukaryotes, encompassing the first robust occurrences of kerogen-bound regular steranes from Tonian rocks, including 21-norcholestane, 27-norcholestane, cholestane, ergostane, and cryostane, along with a novel unidentified C30 sterane series from our least thermally mature Chuar Group samples. Appreciable values for the sterane/hopane (S/H) ratio are found for both the free and kerogen-bound biomarker pools for both the Chuar Group rocks (S/H between 0.09 and 1.26) and the Visingsö Group samples (S/H between 0.03 and 0.37). The more organic-rich rock samples generally yield higher S/H ratios than for organic-lean substrates, which suggests a marine nutrient control on eukaryotic abundance relative to bacteria. A C27 sterane (cholestane) predominance among total C26 -C30 steranes is a common feature found for all samples investigated, with lower amounts of C28 steranes (ergostane and crysotane) also present. No traces of known ancient C30 sterane compounds; including 24-isopropylcholestanes, 24-n-propylcholestanes, or 26-methylstigmastanes, are detectable in any of these pre-Sturtian rocks. These biomarker characteristics support the view that the Tonian Period was a key interval in the history of life on our planet since it marked the transition from a bacterially dominated marine biosphere to an ocean system which became progressively enriched with eukaryotes. The eukaryotic source organisms likely encompassed photosynthetic primary producers, marking a rise in red algae, and consumers in a revamped trophic structure predating the Sturtian glaciation.
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Affiliation(s)
- J. Alex Zumberge
- Department of Earth and Planetary Sciences, University of California, Riverside, CA, USA
| | | | - Gordon D. Love
- Department of Earth and Planetary Sciences, University of California, Riverside, CA, USA
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15
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Reinhard CT, Planavsky NJ, Ward BA, Love GD, Le Hir G, Ridgwell A. The impact of marine nutrient abundance on early eukaryotic ecosystems. GEOBIOLOGY 2020; 18:139-151. [PMID: 32065509 DOI: 10.1111/gbi.12384] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Accepted: 11/05/2019] [Indexed: 06/10/2023]
Abstract
The rise of eukaryotes to ecological prominence represents one of the most dramatic shifts in the history of Earth's biosphere. However, there is an enigmatic temporal lag between the emergence of eukaryotic organisms in the fossil record and their much later ecological expansion. In parallel, there is evidence for a secular increase in the availability of the key macronutrient phosphorus (P) in Earth's oceans. Here, we use an Earth system model equipped with a size-structured marine ecosystem to explore relationships between plankton size, trophic complexity, and the availability of marine nutrients. We find a strong dependence of planktonic ecosystem structure on ocean nutrient abundance, with a larger ocean nutrient inventory leading to greater overall biomass, broader size spectra, and increasing abundance of large Zooplankton. If existing estimates of Proterozoic marine nutrient levels are correct, our results suggest that increases in the ecological impact of eukaryotic algae and trophic complexity in eukaryotic ecosystems were directly linked to restructuring of the global P cycle associated with the protracted rise of surface oxygen levels. Our results thus suggest an indirect but potentially important mechanism by which ocean oxygenation may have acted to shape marine ecological function during late Proterozoic time.
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Affiliation(s)
- Christopher T Reinhard
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, Georgia
- NASA Astrobiology Institute, Alternative Earths Team, Riverside, California
| | - Noah J Planavsky
- NASA Astrobiology Institute, Alternative Earths Team, Riverside, California
- Department of Geology and Geophysics, Yale University, New Haven, Connecticut
| | - Ben A Ward
- Ocean and Earth Science, University of Southampton, Southampton, UK
| | - Gordon D Love
- NASA Astrobiology Institute, Alternative Earths Team, Riverside, California
- Department of Earth and Planetary Sciences, University of California, Riverside, California
| | | | - Andy Ridgwell
- NASA Astrobiology Institute, Alternative Earths Team, Riverside, California
- Department of Earth and Planetary Sciences, University of California, Riverside, California
- School of Geographical Sciences, University of Bristol, Bristol, UK
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16
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Hodgskiss MSW, Crockford PW, Peng Y, Wing BA, Horner TJ. A productivity collapse to end Earth's Great Oxidation. Proc Natl Acad Sci U S A 2019; 116:17207-17212. [PMID: 31405980 PMCID: PMC6717284 DOI: 10.1073/pnas.1900325116] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
It has been hypothesized that the overall size of-or efficiency of carbon export from-the biosphere decreased at the end of the Great Oxidation Event (GOE) (ca. 2,400 to 2,050 Ma). However, the timing, tempo, and trigger for this decrease remain poorly constrained. Here we test this hypothesis by studying the isotope geochemistry of sulfate minerals from the Belcher Group, in subarctic Canada. Using insights from sulfur and barium isotope measurements, combined with radiometric ages from bracketing strata, we infer that the sulfate minerals studied here record ambient sulfate in the immediate aftermath of the GOE (ca. 2,018 Ma). These sulfate minerals captured negative triple-oxygen isotope anomalies as low as ∼ -0.8‰. Such negative values occurring shortly after the GOE require a rapid reduction in primary productivity of >80%, although even larger reductions are plausible. Given that these data imply a collapse in primary productivity rather than export efficiency, the trigger for this shift in the Earth system must reflect a change in the availability of nutrients, such as phosphorus. Cumulatively, these data highlight that Earth's GOE is a tale of feast and famine: A geologically unprecedented reduction in the size of the biosphere occurred across the end-GOE transition.
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Affiliation(s)
| | - Peter W Crockford
- Department of Earth and Planetary Sciences, Weizmann Institute of Science, 761000 Rehovot, Israel;
- Department of Geoscience, Princeton University, Princeton, NJ 08544
| | - Yongbo Peng
- School of Earth Sciences and Engineering, Nanjing University, 210023 Nanjing, China
| | - Boswell A Wing
- Department of Geological Sciences, University of Colorado Boulder, Boulder, CO 80309
| | - Tristan J Horner
- Non-traditional Isotope Research on Various Advanced Novel Applications (NIRVANA) Labs, Woods Hole Oceanographic Institution, Woods Hole, MA 02543
- Department of Marine Chemistry & Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA 02543
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17
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Ward LM, Shih PM. The evolution and productivity of carbon fixation pathways in response to changes in oxygen concentration over geological time. Free Radic Biol Med 2019; 140:188-199. [PMID: 30790657 DOI: 10.1016/j.freeradbiomed.2019.01.049] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 01/12/2019] [Accepted: 01/31/2019] [Indexed: 12/25/2022]
Abstract
The fixation of inorganic carbon species like CO2 to more reduced organic forms is one of the most fundamental processes of life as we know it. Although several carbon fixation pathways are known to exist, on Earth today nearly all global carbon fixation is driven by the Calvin cycle in oxygenic photosynthetic plants, algae, and Cyanobacteria. At other times in Earth history, other organisms utilizing different carbon fixation pathways may have played relatively larger roles, with this balance shifting over geological time as the environmental context of life has changed and evolutionary innovations accumulated. Among the most dramatic changes that our planet and the biosphere have undergone are those surrounding the rise of O2 in our atmosphere-first during the Great Oxygenation Event at ∼2.3 Ga, and perhaps again during Neoproterozoic or Paleozoic time. These oxygenation events likely represent major step changes in the tempo and mode of biological productivity as a result of the increased productivity of oxygenic photosynthesis and the introduction of O2 into geochemical and biological systems, and likely involved shifts in the relative contribution of different carbon fixation pathways. Here, we review what is known from both the rock record and comparative biology about the evolution of carbon fixation pathways, their contributions to primary productivity through time, and their relationship to the evolving oxygenation state of the fluid Earth following the evolution and expansion of oxygenic photosynthesis.
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Affiliation(s)
- Lewis M Ward
- Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA, United States.
| | - Patrick M Shih
- Department of Plant Biology, University of California, Davis, Davis, CA, United States; Department of Energy, Feedstocks Division, Joint BioEnergy Institute, Emeryville, CA, United States; Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States.
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18
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Ozaki K, Thompson KJ, Simister RL, Crowe SA, Reinhard CT. Anoxygenic photosynthesis and the delayed oxygenation of Earth's atmosphere. Nat Commun 2019; 10:3026. [PMID: 31289261 PMCID: PMC6616575 DOI: 10.1038/s41467-019-10872-z] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Accepted: 05/28/2019] [Indexed: 12/03/2022] Open
Abstract
The emergence of oxygenic photosynthesis created a new niche with dramatic potential to transform energy flow through Earth's biosphere. However, more primitive forms of photosynthesis that fix CO2 into biomass using electrons from reduced species like Fe(II) and H2 instead of water would have competed with Earth's early oxygenic biosphere for essential nutrients. Here, we combine experimental microbiology, genomic analyses, and Earth system modeling to demonstrate that competition for light and nutrients in the surface ocean between oxygenic phototrophs and Fe(II)-oxidizing, anoxygenic photosynthesizers (photoferrotrophs) translates into diminished global photosynthetic O2 release when the ocean interior is Fe(II)-rich. These results provide a simple ecophysiological mechanism for inhibiting atmospheric oxygenation during Earth's early history. We also find a novel positive feedback within the coupled C-P-O-Fe cycles that can lead to runaway planetary oxygenation as rising atmospheric pO2 sweeps the deep ocean of the ferrous iron substrate for photoferrotrophy.
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Affiliation(s)
- Kazumi Ozaki
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, 30332, USA
- NASA Astrobiology Institute, Alternative Earths Team, Riverside, CA, USA
- NASA Postdoctoral Program, Universities Space Research Association, Columbia, MD, 21046, USA
- Department of Environmental Science, Toho University, Funabashi, Chiba, 274-8510, Japan
| | - Katharine J Thompson
- Departments of Microbiology & Immunology and Earth, Ocean, & Atmospheric Sciences, University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - Rachel L Simister
- Departments of Microbiology & Immunology and Earth, Ocean, & Atmospheric Sciences, University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - Sean A Crowe
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, 30332, USA
- Departments of Microbiology & Immunology and Earth, Ocean, & Atmospheric Sciences, University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - Christopher T Reinhard
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, 30332, USA.
- NASA Astrobiology Institute, Alternative Earths Team, Riverside, CA, USA.
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