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González AG, Poitrasson F, Jiménez-Villacorta F, Shirokova LS, Pokrovsky OS. Contrasted redox-dependent structural control on Fe isotope fractionation during its adsorption onto and assimilation by heterotrophic soil bacteria. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2024; 26:344-356. [PMID: 38169006 DOI: 10.1039/d3em00332a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Despite the importance of structural control on metal stable isotope fractionation in inorganic and abiotic systems, the link between metal structural changes and related isotopic fractionation during reactions with organic surfaces and live cells remains poorly established. We conducted reversible adsorption of Fe(II) and Fe(III) on the surface of exopolysaccharide (EPS)-rich and EPS-poor Pseudomonas aureofaciens, and we allowed Fe intracellular uptake by growing cells. We analyzed the Fe isotopic composition of the remaining fluid and cell biomass, and compared the isotopic fractionation during adsorption and assimilation reaction with relative changes in Fe structural status between aqueous solution and bacterial cells, based on available and newly collected X-ray absorption spectroscopy (XAS) observations. Iron(III) adsorption onto P. aureofaciens at 2.8 ≤ pH ≤ 6.0 produced an enrichment of the cell surface in heavier isotopes with Δ57Fecell-solution ranging from +0.7 to +2.1‰, without a link to pH in EPS-rich cultures. In contrast, the magnitude of isotopic fractionation increased with pH in EPS-poor cultures. Iron(II) adsorption produced an even larger enrichment of the cell surface in heavier isotopes, by up to 3.2‰, tentatively linked to Fe(III) hydroxide precipitation. Intracellular assimilation of Fe(II) favored heavier isotopes and led to Δ57Fecell-solution of +0.8‰. In addition, Fe(III) cellular uptake produced an enrichment of the bacterial biomass in lighter isotopes with Δ57Fecell-solution of -1‰. The XAS analyses demonstrated the dominance of Fe(III)-phosphate complexes both at the cell surface and in the cell interior. We suggest that heavier isotope enrichment of the cell surface relative to the aqueous solution is due to strong Fe(III)-phosphoryl surface complexes and Fe complexation to ligands responsible for metal transfer from the surface to the inner cell. In case of Fe(II) adsorption or assimilation, its partial oxidation within the cell compartments may lead to cell enrichment in heavier isotopes. In contrast, loss of symmetry of assimilated Fe(III) relative to the aqueous Fe3+ ion and longer bonds of intracellular ions relative to aqueous Fe(III)-citrate or hydroxo-complexes could produce an enrichment of cells in lighter isotopes. The versatile nature of Fe(II) and Fe(III) fractionation without a distinct effect of pH and surface exopolysaccharide coverage suggests that, in natural soil and sedimentary environments, Fe isotope fractionation during interaction with heterotrophic bacteria will be primarily governed by Fe complexation with DOM and Fe redox status in the soil pore water.
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Affiliation(s)
- Aridane G González
- Instituto de Oceanografía y Cambio Global, IOCAG, Universidad de Las Palmas de Gran Canaria, ULPGC, Spain.
| | - Franck Poitrasson
- Géosciences Environnement Toulouse (GET), CNRS UMR 5563, UPS-IRD-CNES 14-16, Avenue Edouard Belin, 31400, Toulouse, France
| | | | - Liudmila S Shirokova
- Géosciences Environnement Toulouse (GET), CNRS UMR 5563, UPS-IRD-CNES 14-16, Avenue Edouard Belin, 31400, Toulouse, France
- N.P. Laverov Federal Center for Integrated Arctic Research (FCIArctic), Russian Academy of Sciences, Arkhangelsk, Russia
| | - Oleg S Pokrovsky
- Géosciences Environnement Toulouse (GET), CNRS UMR 5563, UPS-IRD-CNES 14-16, Avenue Edouard Belin, 31400, Toulouse, France
- BIO-GEO-CLIM Laboratory, National Research Tomsk State University, Tomsk, Russia
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Zhong S, Yu S, Liu Y, Gao R, Pan D, Chen G, Li X, Liu T, Liu C, Li F. Impact of Flooding-Drainage Alternation on Fe Uptake and Transport in Rice: Novel Insights from Iron Isotopes. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2024; 72:1500-1508. [PMID: 38165827 DOI: 10.1021/acs.jafc.3c07640] [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: 01/04/2024]
Abstract
Iron (Fe) isotopes were utilized to provide insights into the temporal changes underlying Fe uptake and translocation during rice growth (tillering, jointing, flowering, and maturity stages) in soil-rice systems under typical flooding-drainage alternation. Fe isotopic composition (δ56Fe values) of the soil solution generally decreased at vegetative stages in flooding regimes but increased during grain-filling. Fe plaques were the prevalent source of Fe uptake, as indicated by the concurrent increase in the δ56Fe values of Fe plaques and rice plants during rice growth. The increasing fractionation magnitude from stem/nodes I to flag leaves can be attributed to the preferred phloem transport of light isotopes toward grains, particularly during grain-filling. This study demonstrates that rice plants take up heavy Fe isotopes from Fe plaque and soil solution via strategy II during flooding and the subsequent drainage period, respectively, thereby providing valuable insights into improving the nutritional quality during rice production.
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Affiliation(s)
- Songxiong Zhong
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-Environmental Pollution Control and Management, Institute of Eco-Environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China
| | - Shan Yu
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-Environmental Pollution Control and Management, Institute of Eco-Environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China
| | - Yuhui Liu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Ruichuan Gao
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-Environmental Pollution Control and Management, Institute of Eco-Environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China
| | - Dandan Pan
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Guojun Chen
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-Environmental Pollution Control and Management, Institute of Eco-Environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China
| | - Xiaomin Li
- SCNU Environmental Research Institute, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Theoretical Chemistry of Environment, South China Normal University, Guangzhou 510006, China
| | - Tongxu Liu
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-Environmental Pollution Control and Management, Institute of Eco-Environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China
| | - Chengshuai Liu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Fangbai Li
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-Environmental Pollution Control and Management, Institute of Eco-Environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China
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3
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Köster M, Staubwasser M, Meixner A, Kasemann SA, Manners HR, Morono Y, Inagaki F, Heuer VB, Kasten S, Henkel S. Uniquely low stable iron isotopic signatures in deep marine sediments caused by Rayleigh distillation. Sci Rep 2023; 13:10281. [PMID: 37355766 DOI: 10.1038/s41598-023-37254-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Accepted: 06/19/2023] [Indexed: 06/26/2023] Open
Abstract
Dissimilatory iron reduction (DIR) is suggested to be one of the earliest forms of microbial respiration. It plays an important role in the biogeochemical cycling of iron in modern and ancient sediments. Since microbial iron cycling is typically accompanied by iron isotope fractionation, stable iron isotopes are used as tracer for biological activity. Here we present iron isotope data for dissolved and sequentially extracted sedimentary iron pools from deep and hot subseafloor sediments retrieved in the Nankai Trough off Japan. Dissolved iron (Fe(II)aq) is isotopically light throughout the ferruginous sediment interval but some samples have exceptionally light isotope values. Such light values have never been reported in natural marine environments and cannot be solely attributed to DIR. We show that the light isotope values are best explained by a Rayleigh distillation model where Fe(II)aq is continuously removed from the pore water by adsorption onto iron (oxyhydr)oxide surfaces. While the microbially mediated Fe(II)aq release has ceased due to an increase in temperature beyond the threshold of mesophilic microorganisms, the abiotic adsorptive Fe(II)aq removal continued, leading to uniquely light isotope values. These findings have important implications for the interpretation of dissolved iron isotope data especially in deep subseafloor sediments.
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Affiliation(s)
- Male Köster
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany.
- Faculty of Geosciences, University of Bremen, Bremen, Germany.
| | | | - Anette Meixner
- Faculty of Geosciences, University of Bremen, Bremen, Germany
- MARUM - Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany
| | - Simone A Kasemann
- Faculty of Geosciences, University of Bremen, Bremen, Germany
- MARUM - Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany
| | - Hayley R Manners
- School of Geography, Earth and Environmental Sciences, University of Plymouth, Plymouth, UK
| | - Yuki Morono
- Kochi Institute for Core Sample Research, Extra-cutting-edge Science and Technology Avant-garde Research (X-star), Japan Agency for Marine-Earth Sciences and Technology (JAMSTEC), Nankoku, Kochi, Japan
| | - Fumio Inagaki
- Institute for Marine-Earth Exploration and Engineering (MarE3), JAMSTEC, Yokohama, Japan
- Department of Earth Sciences, Graduate School of Science, Tohoku University, Sendai, Japan
| | - Verena B Heuer
- MARUM - Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany
| | - Sabine Kasten
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany
- Faculty of Geosciences, University of Bremen, Bremen, Germany
- MARUM - Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany
| | - Susann Henkel
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany
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Runge EA, Mansor M, Kappler A, Duda JP. Microbial biosignatures in ancient deep-sea hydrothermal sulfides. GEOBIOLOGY 2023; 21:355-377. [PMID: 36524457 DOI: 10.1111/gbi.12539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 11/03/2022] [Accepted: 12/03/2022] [Indexed: 06/17/2023]
Abstract
Deep-sea hydrothermal systems provide ideal conditions for prebiotic reactions and ancient metabolic pathways and, therefore, might have played a pivotal role in the emergence of life. To understand this role better, it is paramount to examine fundamental interactions between hydrothermal processes, non-living matter, and microbial life in deep time. However, the distribution and diversity of microbial communities in ancient deep-sea hydrothermal systems are still poorly constrained, so evolutionary, and ecological relationships remain unclear. One important reason is an insufficient understanding of the formation of diagnostic microbial biosignatures in such settings and their preservation through geological time. This contribution centers around microbial biosignatures in Precambrian deep-sea hydrothermal sulfide deposits. Intending to provide a valuable resource for scientists from across the natural sciences whose research is concerned with the origins of life, we first introduce different types of biosignatures that can be preserved over geological timescales (rock fabrics and textures, microfossils, mineral precipitates, carbonaceous matter, trace metal, and isotope geochemical signatures). We then review selected reports of biosignatures from Precambrian deep-sea hydrothermal sulfide deposits and discuss their geobiological significance. Our survey highlights that Precambrian hydrothermal sulfide deposits potentially encode valuable information on environmental conditions, the presence and nature of microbial life, and the complex interactions between fluids, micro-organisms, and minerals. It further emphasizes that the geobiological interpretation of these records is challenging and requires the concerted application of analytical and experimental methods from various fields, including geology, mineralogy, geochemistry, and microbiology. Well-orchestrated multidisciplinary studies allow us to understand the formation and preservation of microbial biosignatures in deep-sea hydrothermal sulfide systems and thus help unravel the fundamental geobiology of ancient settings. This, in turn, is critical for reconstructing life's emergence and early evolution on Earth and the search for life elsewhere in the universe.
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Affiliation(s)
- Eric Alexander Runge
- Sedimentology and Organic Geochemistry, Department of Geosciences, Tübingen University, Tübingen, Germany
| | - Muammar Mansor
- Geomicrobiology, Department of Geosciences, Tübingen University, Tübingen, Germany
| | - Andreas Kappler
- Geomicrobiology, Department of Geosciences, Tübingen University, Tübingen, Germany
- Cluster of Excellence EXC 2124, Controlling Microbes to Fight Infection, Tübingen, Germany
| | - Jan-Peter Duda
- Sedimentology and Organic Geochemistry, Department of Geosciences, Tübingen University, Tübingen, Germany
- Geobiology, Geoscience Center, Göttingen University, Göttingen, Germany
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5
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Fan C, Guo C, Chen W, Lu G, Shen Y, Dang Z. Fe(II)-mediated transformation of schwertmannite associated with calcium from acid mine drainage treatment. J Environ Sci (China) 2023; 126:612-620. [PMID: 36503787 DOI: 10.1016/j.jes.2022.05.044] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 05/21/2022] [Accepted: 05/22/2022] [Indexed: 06/17/2023]
Abstract
Schwertmannite is an important Fe(III)-oxyhydroxysulfate in acid mine drainage (AMD) polluted areas and its stability depends on surrounding environmental factors and previously bound elements. The treatment and neutralization of AMD normally involve the use of lime, which leads to the discharge of abundant Ca in the mining area. Such an environmental disturbance brings up an important and less considered problem of how the reductive transformation of schwertmannite associated with coexisting Ca occurred. Here, the Fe(II)-mediated transformation of Ca-adsorbed schwertmannite and subsequent Ca repartitioning behaviors were investigated. Results showed that adsorbed Ca had a weak inhibitory effect on Fe(II)-mediated schwertmannite transformation. Release of SO42- and SEM images both indicated that transformation rates of schwertmannite decreased under the influence of adsorbed Ca. XRD patterns indicated that adsorbed Ca altered schwertmannite transformation pathways and product compositions upon treatment with 0.4 mmol/L Fe(II). The end products of Sch notably contained both goethite and lepidocrocite; however, transformation products of SchCa only contained goethite all along. Approximately 33.5% of the surface adsorbed-Ca was released into solution within 6 hr after Fe(II) injection. Aqueous Ca behaved in a "first release and then im-mobilization" manner, which indicated dissolution and secondary mineralization drove Ca migration during the Fe(II)-mediated transformation of SchCa. Adsorbed Ca blocked the surface sites for subsequent Fe(II) adsorption, limited the Fe(II)-Fe(III) ETAE, and decreased the transformation rates. This work sheds light on the complex geochemical behavior of schwertmannite under the influences of environmental perturbations in AMD environments.
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Affiliation(s)
- Cong Fan
- National Research Base of Intelligent Manufacturing Service, Chongqing Technology and Business University, Chongqing 400067, China
| | - Chuling Guo
- School of Environment and Energy, South China University of Technology, Guangzhou 510006, China; The Key Laboratory of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, South China University of Technology, Guangzhou 510006, China.
| | - Wei Chen
- Chongqing Key Laboratory of Environmental Materials and Remediation Technologies, Chongqing University of Arts and Sciences, Chongqing 402160, China.
| | - Guining Lu
- School of Environment and Energy, South China University of Technology, Guangzhou 510006, China; The Key Laboratory of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, South China University of Technology, Guangzhou 510006, China
| | - Yu Shen
- National Research Base of Intelligent Manufacturing Service, Chongqing Technology and Business University, Chongqing 400067, China
| | - Zhi Dang
- School of Environment and Energy, South China University of Technology, Guangzhou 510006, China; The Key Laboratory of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, South China University of Technology, Guangzhou 510006, China
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6
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Xie J, Coker VS, O'Driscoll B, Cai R, Haigh SJ, Lloyd JR. Microbial Reduction of Antimony(V)-Bearing Ferrihydrite by Geobacter sulfurreducens. Appl Environ Microbiol 2023; 89:e0217522. [PMID: 36853045 PMCID: PMC10057881 DOI: 10.1128/aem.02175-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Accepted: 02/05/2023] [Indexed: 03/01/2023] Open
Abstract
The reduction of Sb(V)-bearing ferrihydrite by Geobacter sulfurreducens was studied to determine the fate of the metalloid in Fe-rich systems undergoing redox transformations. Sb(V) added at a range of concentrations adsorbed readily to ferrihydrite, and the loadings had a pronounced impact on the rate and extent of Fe(III) reduction and the products formed. Magnetite dominated at low (0.5 and 1 mol%) Sb(V) concentrations, with crystallite sizes decreasing at higher Sb loadings: 37-, 25-, and 17-nm particles for no-Sb, 0.5% Sb, and 1% Sb samples, respectively. In contrast, goethite was the dominant end product for samples with higher antimony loadings (2 and 5 mol%), with increased goethite grain size in the 5% Sb sample. Inductively coupled mass spectrometry (ICP-MS) analysis confirmed that Sb was not released to solution during the bioreduction process, and X-ray photoelectron spectroscopy (XPS) analyses showed that no Sb(III) was formed throughout the experiments, confirming that the Fe(III)-reducing bacterium Geobacter sulfurreducens cannot reduce Sb(V) enzymatically or via biogenic Fe(II). These findings suggest that Fe (bio)minerals have a potential role in limiting antimony pollution in the environment, even when undergoing redox transformations. IMPORTANCE Antimony is an emerging contaminant that shares chemical characteristics with arsenic. Metal-reducing bacteria (such as Geobacter sulfurreducens) can cause the mobilization of arsenic from Fe(III) minerals under anaerobic conditions, causing widespread contamination of aquifers worldwide. This research explores whether metal-reducing bacteria can drive the mobilization of antimony under similar conditions. In this study, we show that G. sulfurreducens cannot reduce Sb(V) directly or cause Sb release during the bioreduction of the Fe(III) mineral ferrihydrite [although the sorbed Sb(V) did alter the Fe(II) mineral end products formed]. Overall, this study highlights the tight associations between Fe and Sb in environmental systems, suggesting that the microbial reduction of Fe(III)/Sb mineral assemblages may not lead to Sb release (in stark contrast to the mobilization of As in iron-rich systems) and offers potential Fe-based remediation options for Sb-contaminated environments.
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Affiliation(s)
- Jinxin Xie
- Williamson Research Centre for Molecular Environmental Science, Department of Earth and Environmental Science, The University of Manchester, Manchester, United Kingdom
| | - Victoria S. Coker
- Williamson Research Centre for Molecular Environmental Science, Department of Earth and Environmental Science, The University of Manchester, Manchester, United Kingdom
| | - Brian O'Driscoll
- Williamson Research Centre for Molecular Environmental Science, Department of Earth and Environmental Science, The University of Manchester, Manchester, United Kingdom
- Department of Earth and Environmental Sciences, The University of Ottawa, Ottawa, Canada
| | - Rongsheng Cai
- Department of Materials, The University of Manchester, Manchester, United Kingdom
| | - Sarah J. Haigh
- Department of Materials, The University of Manchester, Manchester, United Kingdom
| | - Jonathan R. Lloyd
- Williamson Research Centre for Molecular Environmental Science, Department of Earth and Environmental Science, The University of Manchester, Manchester, United Kingdom
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7
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Yin NH, Louvat P, Thibault-DE-Chanvalon A, Sebilo M, Amouroux D. Iron isotopic fractionation driven by low-temperature biogeochemical processes. CHEMOSPHERE 2023; 316:137802. [PMID: 36640969 DOI: 10.1016/j.chemosphere.2023.137802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Revised: 01/06/2023] [Accepted: 01/08/2023] [Indexed: 06/17/2023]
Abstract
Iron is geologically important and biochemically crucial for all microorganisms, plants and animals due to its redox exchange, the involvement in electron transport and metabolic processes. Despite the abundance of iron in the earth crust, its bioavailability is very limited in nature due to its occurrence as ferrihydrite, goethite, and hematite where they are thermodynamically stable with low dissolution kinetics in neutral or alkaline environments. Organisms such as bacteria, fungi, and plants have evolved iron acquisition mechanisms to increase its bioavailability in such environments, thereby, contributing largely to the iron cycle in the environment. Biogeochemical cycling of metals including Fe in natural systems usually results in stable isotope fractionation; the extent of fractionation depends on processes involved. Our review suggests that significant fractionation of iron isotopes occurs in low-temperature environments, where the extent of fractionation is greatly governed by several biogeochemical processes such as redox reaction, alteration, complexation, adsorption, oxidation and reduction, with or without the influence of microorganisms. This paper includes relevant data sets on the theoretical calculations, experimental prediction, as well as laboratory studies on stable iron isotopes fractionation induced by different biogeochemical processes.
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Affiliation(s)
- Nang-Htay Yin
- Universite de Pau et des Pays de L'Adour, E2S UPPA, CNRS, IPREM, Institut des Sciences Analytiques et de Physico-chimie pour L'Environnement et Les Matériaux, Pau, France.
| | - Pascale Louvat
- Universite de Pau et des Pays de L'Adour, E2S UPPA, CNRS, IPREM, Institut des Sciences Analytiques et de Physico-chimie pour L'Environnement et Les Matériaux, Pau, France
| | - Aubin Thibault-DE-Chanvalon
- Universite de Pau et des Pays de L'Adour, E2S UPPA, CNRS, IPREM, Institut des Sciences Analytiques et de Physico-chimie pour L'Environnement et Les Matériaux, Pau, France
| | - Mathieu Sebilo
- Universite de Pau et des Pays de L'Adour, E2S UPPA, CNRS, IPREM, Institut des Sciences Analytiques et de Physico-chimie pour L'Environnement et Les Matériaux, Pau, France; Sorbonne Université, CNRS, IEES, Paris, France
| | - David Amouroux
- Universite de Pau et des Pays de L'Adour, E2S UPPA, CNRS, IPREM, Institut des Sciences Analytiques et de Physico-chimie pour L'Environnement et Les Matériaux, Pau, France
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Fitzsimmons JN, Conway TM. Novel Insights into Marine Iron Biogeochemistry from Iron Isotopes. ANNUAL REVIEW OF MARINE SCIENCE 2023; 15:383-406. [PMID: 36100217 DOI: 10.1146/annurev-marine-032822-103431] [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: 06/15/2023]
Abstract
The micronutrient iron plays a major role in setting the magnitude and distribution of primary production across the global ocean. As such, an understanding of the sources, sinks, and internal cycling processes that drive the oceanic distribution of iron is key to unlocking iron's role in the global carbon cycle and climate, both today and in the geologic past. Iron isotopic analyses of seawater have emerged as a transformative tool for diagnosing iron sources to the ocean and tracing biogeochemical processes. In this review, we summarize the end-member isotope signatures of different iron source fluxes and highlight the novel insights into iron provenance gained using this tracer. We also review ways in which iron isotope fractionation might be used to understand internal oceanic cycling of iron, including speciation changes, biological uptake, and particle scavenging. We conclude with an overview of future research needed to expand the utilization of this cutting-edge tracer.
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Affiliation(s)
| | - Tim M Conway
- College of Marine Science, University of South Florida, St. Petersburg, Florida, USA;
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Han R, Zhang Q, Xu Z. Tracing Fe cycle isotopically in soils based on different land uses: Insight from a typical karst catchment, Southwest China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 856:158929. [PMID: 36152861 DOI: 10.1016/j.scitotenv.2022.158929] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2022] [Revised: 09/01/2022] [Accepted: 09/18/2022] [Indexed: 06/16/2023]
Abstract
Iron (Fe) isotopes can effectively unveil the Fe cycle mechanisms under redox and biological conditions during the weathering and pedogenic processes. Fe contents and Fe isotope compositions (defined as δ56Fe) in the soil profiles under secondary forest land, abandoned cropland and shrubland were investigated in a typical karst area in Southwest China. The results showed that the Fe content ranged from 23.92 to 38.56 g/kg, 21.92 to 33.02 g/kg and 12.98 to 27.93 g/kg, and the δ56Fe levels varied from -0.48 ‰ to 0.21 ‰, -0.24 ‰ to 0.11 ‰ and - 0.11 ‰ to 0.16 ‰ from the secondary forest land, abandoned cropland and shrubland, respectively. The correlation analysis results showed that Fe transportation and isotopic fractionation were regulated by the redox processes through soil pH and soil organic matter (SOM) in the abandoned cropland and shrubland. Heavier Fe isotope may be accumulated in the deeper soil of secondary forest land due to Fe-oxide precipitation. The Fe isotope fractionations were greatly altered by soil organic carbon (SOC) in surface soils due to negative surface charges. Soil pH also plays a key role in enriching lighter Fe in a medium-acidic environment (shrubland) by ligand-controlled dissolution and reductive dissolution. Long-term cultivation in abandoned cropland and grazing in shrubland reshaped the Fe cycle in soil profiles by changing soil pH and SOC contents. However, the similar values of δ56Fe in different land use soils indicated that the agricultural activities have no significant impact on the Fe transformation in karst soil ecosystems. The land utilization is reasonable in the Yinjiang County. This study provided effective data and insightful analysis to understand the Fe cycle processes in the karst soils under varied land uses.
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Affiliation(s)
- Ruiyin Han
- Key Laboratory of Cenozoic Geology and Environment, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China; University of Chinese Academy of Sciences, Beijing 100049, China; CAS Center for Excellence in Life and Paleoenvironment, Beijing 100044, China
| | - Qian Zhang
- Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China.
| | - Zhifang Xu
- Key Laboratory of Cenozoic Geology and Environment, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China; University of Chinese Academy of Sciences, Beijing 100049, China; CAS Center for Excellence in Life and Paleoenvironment, Beijing 100044, China
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10
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van de Velde SJ, Dale AW, Arndt S. Bioturbation and the δ 56Fe signature of dissolved iron fluxes from marine sediments. ROYAL SOCIETY OPEN SCIENCE 2023; 10:220010. [PMID: 36704258 PMCID: PMC9874279 DOI: 10.1098/rsos.220010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Accepted: 01/05/2023] [Indexed: 06/18/2023]
Abstract
We developed a reaction-transport model capable of tracing iron isotopes in marine sediments to quantify the influence of bioturbation on the isotopic signature of the benthic dissolved (DFe) flux. By fitting the model to published data from marine sediments, we calibrated effective overall fractionation factors for iron reduction (-1.3‰), oxidation (+0.4‰), iron-sulfide precipitation (+0.5‰) and dissolution (-0.5‰) and pyrite precipitation (-0.7‰) that agree with literature values. Results show that for bottom-water oxygen concentrations greater than 50 µM, higher bioturbation increased the benthic DFe flux and its δ 56Fe signature. By contrast, for oxygen concentrations less than 50 µM, higher bioturbation decreased the benthic DFe flux and its δ 56Fe signature. The expressed overall fractionation of the benthic DFe flux relative to the δ 56Fe of the iron oxides entering the sediment ranges from -1.67‰ to 0.0‰. On a global scale, the presence of bioturbation increases sedimentary DFe release from approximately 70 G mol DFe yr-1 to approximately 160 G mol DFe yr-1 and decreases the δ 56Fe signature of the DFe flux.
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Affiliation(s)
- Sebastiaan J. van de Velde
- Department of Geoscience, Environment & Society, Université Libre de Bruxelles, Av. F. Roosevelt 50, CP160/02, 1050 Brussels, Belgium
- Operational Directorate Natural Environment, Royal Belgian Institute of Natural Sciences, Rue Vautier 29, Brussels, Belgium
| | - Andrew W. Dale
- GEOMAR Helmholtz Centre for Ocean Research Kiel, Wischhofstr. 1-3, D-24148 Kiel, Germany
| | - Sandra Arndt
- Department of Geoscience, Environment & Society, Université Libre de Bruxelles, Av. F. Roosevelt 50, CP160/02, 1050 Brussels, Belgium
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11
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Zhang Q, Liu M, Zhang S, Wang L, Zhu G. Environmental implications of agricultural abandonment on Fe cycling: Insight from iron forms and stable isotope composition in karst soil, southwest China. ENVIRONMENTAL RESEARCH 2022; 215:114377. [PMID: 36152887 DOI: 10.1016/j.envres.2022.114377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2022] [Revised: 09/15/2022] [Accepted: 09/15/2022] [Indexed: 06/16/2023]
Abstract
Land-use change influences the fate of nutrient elements, including iron (Fe), and then threaten soil security. In this study, Fe forms and stable isotope composition (δ56Fe) in soils were investigated to identify the variations in the processes of Fe cycling during agricultural abandonment in a karst region of Southwest China. Soil δ56Fe compositions varied from -0.05‰-0.02‰ in croplands, 0.05‰-0.12‰ in abandoned croplands, to 0.30‰-0.80‰ in the native vegetation lands. In the croplands, Fe oxidation-precipitation process is considered as the main contributor to Fe migration and isotope fractionation, leading to a relatively enrichment of heavier Fe isotope in deeper soil layer. In the abandoned croplands and native vegetation lands, Fe isotope in the organic-rich layer (0-10 cm) was significantly lighter than that in subsurface layer (20-30 cm), mainly due to the recovery of soil organic carbon (SOC) and macro-aggregate after cropland abandonment. Moreover, the eluviation process mainly caused a decrease in soil Fe contents and enrichment of heavy Fe isotope in deeper soils (below 40 cm). The positive correlation between oxidized Fe and SOC contents suggested the accumulation of mobile Fe in soils after agricultural abandonment, which is beneficial for Fe uptake and assimilation by plants. This study suggests that agricultural abandonment significantly reduce soil Fe leaching loss and improve plant Fe supply by SOC accumulation in surface soil, which gives an environmental implication for the management of soil nutrients.
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Affiliation(s)
- Qian Zhang
- Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences, Beijing, 100101, China.
| | - Man Liu
- Institute of Earth Sciences, China University of Geosciences (Beijing), Beijing, 100083, China
| | - Shitong Zhang
- Institute of Earth Sciences, China University of Geosciences (Beijing), Beijing, 100083, China
| | - Lingqing Wang
- Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences, Beijing, 100101, China
| | - Guangyou Zhu
- Research Institute of Petroleum Exploration and Development, Beijing, 100083, China
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12
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Liu K, Schiff SL, Wu L, Molot LA, Venkiteswaran JJ, Paterson MJ, Elgood RJ, Tsuji JM, Neufeld JD. Large Fractionation in Iron Isotopes Implicates Metabolic Pathways for Iron Cycling in Boreal Shield Lakes. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:14840-14851. [PMID: 36162065 DOI: 10.1021/acs.est.2c04247] [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: 06/16/2023]
Abstract
Stable Fe isotopes have only recently been measured in freshwater systems, mainly in meromictic lakes. Here we report the δ56Fe of dissolved, particulate, and sediment Fe in two small dimictic boreal shield headwater lakes: manipulated eutrophic Lake 227, with annual cyanobacterial blooms, and unmanipulated oligotrophic Lake 442. Within the lakes, the range in δ56Fe is large (ca. -0.9 to +1.8‰), spanning more than half the entire range of natural Earth surface samples. Two layers in the water column with distinctive δ56Fe of dissolved (dis) and particulate (spm) Fe were observed, despite differences in trophic states. In the epilimnia of both lakes, a large Δ56Fedis-spm fractionation of 0.4-1‰ between dissolved and particulate Fe was only observed during cyanobacterial blooms in Lake 227, possibly regulated by selective biological uptake of isotopically light Fe by cyanobacteria. In the anoxic layers in both lakes, upward flux from sediments dominates the dissolved Fe pool with an apparent Δ56Fedis-spm fractionation of -2.2 to -0.6‰. Large Δ56Fedis-spm and previously published metagenome sequence data suggest active Fe cycling processes in anoxic layers, such as microaerophilic Fe(II) oxidation or photoferrotrophy, could regulate biogeochemical cycling. Large fractionation of stable Fe isotopes in these lakes provides a potential tool to probe Fe cycling and the acquisition of Fe by cyanobacteria, with relevance for understanding biogeochemical cycling of Earth's early ferruginous oceans.
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Affiliation(s)
- Kai Liu
- Department of Earth and Environmental Sciences, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
- Water Institute, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Sherry L Schiff
- Department of Earth and Environmental Sciences, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
- Water Institute, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Lingling Wu
- Department of Earth and Environmental Sciences, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
- Water Institute, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Lewis A Molot
- Faculty of Environmental and Urban Change, York University, Toronto, Ontario M3J 1P3, Canada
| | - Jason J Venkiteswaran
- Department of Geography and Environmental Studies, Wilfrid Laurier University, Waterloo, Ontario N2L 3C5, Canada
| | | | - Richard J Elgood
- Department of Earth and Environmental Sciences, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
- Water Institute, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Jackson M Tsuji
- Department of Biology, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1
| | - Josh D Neufeld
- Water Institute, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
- Department of Biology, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1
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13
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Yang X, Guo Q, Boyko V, Avetisyan K, Findlay AJ, Huang F, Wang Z, Chen Z. Isotopic reconstruction of iron oxidation-reduction process based on an Archean Ocean analogue. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 817:152609. [PMID: 34963590 DOI: 10.1016/j.scitotenv.2021.152609] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 12/17/2021] [Accepted: 12/18/2021] [Indexed: 06/14/2023]
Abstract
The chemical composition and redox conditions of the Precambrian ocean are key factors for reconstructing the temporal evolution of atmospheric oxygen through time. In particular, the isotopic composition of iron are useful proxies for reconstructing paleo-ocean environments. Yet, respective processes and related signatures are poorly constrained, hindering the reconstruction of iron redox mechanisms in the Archean ocean. This study centers on Sihailongwan Lake, a stratified water body with a euxinic lower water column considered as an Archean ocean analogue. Results show that the anaerobic oxidation layer is so different from other similar lakes in which dissolved Fe oxidation is present in redoxcline layer. And the fractionation factor between ferrous Fe and iron hydroxide observed in nature water body of Sihailongwan Lake reaches to 2.6‰, which would benefit the production of the oxidations of BIF in sediment. By the spatial distribution of Fe isotope, the benthic water in autumn and the hypolimnetic anoxic water in spring has been identified as iron sulfide zone, where iron isotopic fractionation factor during iron sulfide formation is 1.16‰, accounting for partial scavenging of dissolved Fe(II) with an associated isotopic fractionation. However, pyrite in the sediment records the iron isotopic signal from the redoxcline but not in the iron sulfide or oxide zones of the water column. Above findings indicate that neither the iron isotope fractionation during partial transfer of ferrous iron to iron sulfide nor the partial oxidation of ferrous iron are recorded as pyrite in sedimentary rock. Importantly, the signal of Fe isotopic fractionation in water was archived in the suspended particulate matter and transferred into the sediment, rather than via ferrous iron directly deposited in the sediment. This study reveals that Fe isotopes from modern natural environments are useful proxies for reconstructing iron oxidation-reduction process during Earth's early history.
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Affiliation(s)
- Xi Yang
- Center for Environmental Remediation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China; Tianjin Key Laboratory of Water Resources and Environment, Tianjin Normal University, Tianjin 300387, China
| | - Qingjun Guo
- Center for Environmental Remediation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Valeria Boyko
- Department of Geological and Environmental Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Khoren Avetisyan
- Department of Geological and Environmental Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Alyssa J Findlay
- Department of Geological and Environmental Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Fang Huang
- CAS Key Laboratory of Crust-Mantle Materials and Environments, School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026, China
| | - Zhongliang Wang
- Tianjin Key Laboratory of Water Resources and Environment, Tianjin Normal University, Tianjin 300387, China
| | - Zhenwu Chen
- CAS Key Laboratory of Crust-Mantle Materials and Environments, School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026, China
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14
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Zhong S, Li X, Li F, Liu T, Pan D, Liu Y, Liu C, Chen G, Gao R. Source and Strategy of Iron Uptake by Rice Grown in Flooded and Drained Soils: Insights from Fe Isotope Fractionation and Gene Expression. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2022; 70:2564-2573. [PMID: 35175773 DOI: 10.1021/acs.jafc.1c08034] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Rice can simultaneously absorb Fe2+ via a strategy I-like system and Fe(III)-phytosiderophore via strategy II from soil. Still, it remains unclear which strategy and source of Fe dominate under distinct water conditions. An isotope signature combined with gene expression was employed to evaluate Fe uptake and transport in a soil-rice system under flooded and drained conditions. Rice of flooded treatment revealed a similar δ56Fe value to that of soils (Δ56Ferice-soil = 0.05‰), while that of drained treatment was lighter than that of the soils (Δ56Ferice-soil = -0.41‰). Calculations indicated that 70.4% of Fe in rice was from Fe plaque under flooded conditions, while Fe was predominantly from soil solution under drained conditions. Up-regulated expression of OsNAAT1, OsTOM2, and OsYSL15 was observed in the root of flooded treatment, while higher expression of OsIRT1 was observed in the drained treatment. These isotopic and genetic results suggested that the Fe(III)-DMA uptake from Fe plaque and Fe2+ uptake from soil solution dominated under flooded and drained conditions, respectively.
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Affiliation(s)
- Songxiong Zhong
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-Environmental Pollution Control and Management, Institute of Eco-Environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China
| | - Xiaomin Li
- SCNU Environmental Research Institute, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Theoretical Chemistry of Environment, South China Normal University, Guangzhou 510006, China
| | - Fangbai Li
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-Environmental Pollution Control and Management, Institute of Eco-Environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China
| | - Tongxu Liu
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-Environmental Pollution Control and Management, Institute of Eco-Environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China
| | - Dandan Pan
- SCNU Environmental Research Institute, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Theoretical Chemistry of Environment, South China Normal University, Guangzhou 510006, China
| | - Yuhui Liu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Chengshuai Liu
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-Environmental Pollution Control and Management, Institute of Eco-Environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Guojun Chen
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-Environmental Pollution Control and Management, Institute of Eco-Environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China
| | - Ruichuan Gao
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-Environmental Pollution Control and Management, Institute of Eco-Environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China
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15
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Wu Z, Li X, Li T, Xiao T, Jiang Y, Qin G. Fe-catalyzed denitrative cyanoalkylation of nitroalkenes with cycloketone oxime esters via reductive C–C bond formation. Org Chem Front 2022. [DOI: 10.1039/d2qo00992g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
An iron catalyzed reductive denitrative cyanoalkylation of nitroalkenes with cycloketone oxime esters using Zn as the reductant has been successfully established in which the NO2 of nitroalkenes eventually acts as a leaving group.
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Affiliation(s)
- Zefeng Wu
- Faculty of Science, Kunming University of Science and Technology, 727 Jingming South Road, Chenggong District, Kunming, 650500, P. R. China
| | - Xiangxiang Li
- Faculty of Science, Kunming University of Science and Technology, 727 Jingming South Road, Chenggong District, Kunming, 650500, P. R. China
| | - Tao Li
- Faculty of Science, Kunming University of Science and Technology, 727 Jingming South Road, Chenggong District, Kunming, 650500, P. R. China
| | - Tiebo Xiao
- Faculty of Science, Kunming University of Science and Technology, 727 Jingming South Road, Chenggong District, Kunming, 650500, P. R. China
| | - Yubo Jiang
- Faculty of Science, Kunming University of Science and Technology, 727 Jingming South Road, Chenggong District, Kunming, 650500, P. R. China
| | - Guiping Qin
- Faculty of Science, Kunming University of Science and Technology, 727 Jingming South Road, Chenggong District, Kunming, 650500, P. R. China
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16
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Decraene MN, Marin-Carbonne J, Bouvier AS, Villeneuve J, Bouden N, Luais B, Deloule E. High-spatial-resolution measurements of iron isotopes in pyrites by secondary ion mass spectrometry using the new Hyperion-II radio-frequency plasma source. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2021; 35:e8986. [PMID: 33095943 DOI: 10.1002/rcm.8986] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 10/20/2020] [Accepted: 10/20/2020] [Indexed: 06/11/2023]
Abstract
RATIONALE Iron isotopic signatures in pyrites are considered as a good proxy for reconstructing paleoenvironmental and local redox conditions. However, the investigation of micro-pyrites less than 20 μm in size has been limited by the available analytical techniques. The development of a new brighter radio-frequency plasma ion source (Hyperion-II source) enhances the spatial resolution by increasing the beam density 10 times compared with the Duoplasmatron source. METHODS Here we present high-spatial-resolution measurements of iron isotopes in pyrites using a 3 nA-3 μm primary 16 O- beam on two Cameca IMS 1280-HR2 ion microprobe instruments equipped with Hyperion sources at CRPG-IPNT (France) and at SwissSIMS (Switzerland). We tested analytical effects, such as topography and crystal orientation, that could induce analytical biases perceptible through variations of the instrumental mass fractionation (IMF). RESULTS The δ56 Fe reproducibility for the Balmat pyrite standard is ±0.25‰ (2 standard deviations) and the typical individual internal error is ±0.10‰ (2 standard errors). The sensitivity on 56 Fe+ was 1.2 × 107 cps/nA/ppm or better. Tests on Balmat pyrites revealed that neither the crystal orientation nor channeling effects seem to significantly influence the IMF. Different pyrite standards (Balmat and SpainCR) were used to test the accuracy of the measurements. Indium mounts must be carefully prepared with a sample topography less than 2 μm, which was checked using an interferometric microscope. Such a topography is negligible for introducing change in the IMF. This new source increases the spatial resolution while maintaining the high precision of analyses and the overall stability of the measurements compared with the previous Duoplasmatron source. CONCLUSIONS A reliable method was developed for performing accurate and high-resolution measurements of micrometric pyrites. The investigation of sedimentary micro-pyrites will improve our understanding of the processes and environmental conditions during pyrite precipitation, including the contribution of primary (microbial activities or abiotic reactions) and secondary (diagenesis and/or hydrothermal fluid circulation) signatures.
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Affiliation(s)
- Marie-Noëlle Decraene
- Institut des Sciences de la Terre, Université de Lausanne, Lausanne, Switzerland
- Université de Lorraine, CNRS, CRPG, Nancy, F-54000, France
| | | | - Anne-Sophie Bouvier
- Institut des Sciences de la Terre, Université de Lausanne, Lausanne, Switzerland
| | | | - Nordine Bouden
- Université de Lorraine, CNRS, CRPG, Nancy, F-54000, France
| | - Béatrice Luais
- Université de Lorraine, CNRS, CRPG, Nancy, F-54000, France
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17
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Lotfi-Kalahroodi E, Pierson-Wickmann AC, Rouxel O, Marsac R, Bouhnik-Le Coz M, Hanna K, Davranche M. More than redox, biological organic ligands control iron isotope fractionation in the riparian wetland. Sci Rep 2021; 11:1933. [PMID: 33479360 PMCID: PMC7820352 DOI: 10.1038/s41598-021-81494-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2020] [Accepted: 12/21/2020] [Indexed: 11/17/2022] Open
Abstract
Although redox reactions are recognized to fractionate iron (Fe) isotopes, the dominant mechanisms controlling the Fe isotope fractionation and notably the role of organic matter (OM) are still debated. Here, we demonstrate how binding to organic ligands governs Fe isotope fractionation beyond that arising from redox reactions. The reductive biodissolution of soil Fe(III) enriched the solution in light Fe isotopes, whereas, with the extended reduction, the preferential binding of heavy Fe isotopes to large biological organic ligands enriched the solution in heavy Fe isotopes. Under oxic conditions, the aggregation/sedimentation of Fe(III) nano-oxides with OM resulted in an initial enrichment of the solution in light Fe isotopes. However, heavy Fe isotopes progressively dominate the solution composition in response to their binding with large biologically-derived organic ligands. Confronted with field data, these results demonstrate that Fe isotope systematics in wetlands are controlled by the OM flux, masking Fe isotope fractionation arising from redox reactions. This work sheds light on an overseen aspect of Fe isotopic fractionation and calls for a reevaluation of the parameters controlling the Fe isotopes fractionation to clarify the interpretation of the Fe isotopic signature.
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Affiliation(s)
| | | | - Olivier Rouxel
- IFREMER, Unité de Géosciences Marines, 29280, Plouzané, France
| | - Rémi Marsac
- Univ. Rennes, CNRS, Géosciences Rennes - UMR 6118, 35000, Rennes, France
| | | | - Khalil Hanna
- Univ. Rennes, Ecole Nationale Supérieure de Chimie de Rennes, CNRS ISCR UMR6226, 35000, Rennes, France
| | - Mélanie Davranche
- Univ. Rennes, CNRS, Géosciences Rennes - UMR 6118, 35000, Rennes, France
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18
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Fortney NW, Beard BL, Hutchings JA, Shields MR, Bianchi TS, Boyd ES, Johnson CM, Roden EE. Geochemical and Stable Fe Isotopic Analysis of Dissimilatory Microbial Iron Reduction in Chocolate Pots Hot Spring, Yellowstone National Park. ASTROBIOLOGY 2021; 21:83-102. [PMID: 32580560 DOI: 10.1089/ast.2019.2058] [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
Chocolate Pots hot spring (CP) is an Fe-rich, circumneutral-pH geothermal spring in Yellowstone National Park. Relic hydrothermal systems have been identified on Mars, and modern hydrothermal environments such as CP are useful for gaining insight into potential pathways for generation of biosignatures of ancient microbial life on Earth and Mars. Fe isotope fractionation is recognized as a signature of dissimilatory microbial iron oxide reduction (DIR) in both the rock record and modern sedimentary environments. Previous studies in CP have demonstrated the presence of DIR in vent pool deposits and show aqueous-/solid-phase Fe isotope variations along the hot spring flow path that may be linked to this process. In this study, we examined the geochemistry and stable Fe isotopic composition of spring water and sediment core samples collected from the vent pool and along the flow path, with the goal of evaluating whether Fe isotopes can serve as a signature of past or present DIR activity. Bulk sediment Fe redox speciation confirmed that DIR is active within the hot spring vent pool sediments (but not in more distal deposits), and the observed Fe isotope fractionation between Fe(II) and Fe(III) is consistent with previous studies of DIR-driven Fe isotope fractionation. However, modeling of sediment Fe isotope distributions indicates that DIR does not produce a unique Fe isotopic signature of DIR in the vent pool environment. Because of rapid chemical and isotopic communication between the vent pool fluid and sediment, sorption of Fe(II) to Fe(III) oxides would produce an isotopic signature similar to DIR despite DIR-driven generation of large quantities of isotopically light solid-associated Fe(II). The possibility exists, however, for preservation of specific DIR-derived Fe(II) minerals such as siderite (which is present in the vent pool deposits), whose isotopic composition could serve as a long-term signature of DIR in relic hot spring environments.
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Affiliation(s)
- Nathaniel W Fortney
- Department of Geoscience, NASA Astrobiology Institute, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Brian L Beard
- Department of Geoscience, NASA Astrobiology Institute, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Jack A Hutchings
- Department of Geological Sciences, University of Florida, Gainesville, Florida, USA
| | - Michael R Shields
- Department of Geological Sciences, University of Florida, Gainesville, Florida, USA
| | - Thomas S Bianchi
- Department of Geological Sciences, University of Florida, Gainesville, Florida, USA
| | - Eric S Boyd
- Department of Microbiology and Immunology, NASA Astrobiology Institute, Montana State University, Bozeman, Montana, USA
| | - Clark M Johnson
- Department of Geoscience, NASA Astrobiology Institute, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Eric E Roden
- Department of Geoscience, NASA Astrobiology Institute, University of Wisconsin-Madison, Madison, Wisconsin, USA
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19
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Zhang F, Battaglia-Brunet F, Hellal J, Joulian C, Gautret P, Motelica-Heino M. Impact of Fe(III) (Oxyhydr)oxides Mineralogy on Iron Solubilization and Associated Microbial Communities. Front Microbiol 2020; 11:571244. [PMID: 33329429 PMCID: PMC7715016 DOI: 10.3389/fmicb.2020.571244] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Accepted: 11/02/2020] [Indexed: 11/16/2022] Open
Abstract
Iron-reducing bacteria (IRB) are strongly involved in Fe cycling in surface environments. Transformation of Fe and associated trace elements is strongly linked to the reactivity of various iron minerals. Mechanisms of Fe (oxyhydr)oxides bio-reduction have been mostly elucidated with pure bacterial strains belonging to Geobacter or Shewanella genera, whereas studies involving mixed IRB populations remain scarce. The present study aimed to evaluate the iron reducing rates of IRB enriched consortia originating from complex environmental samples, when grown in presence of Fe (oxyhydr)oxides of different mineralogy. The abundances of Geobacter and Shewanella were assessed in order to acquire knowledge about the abundance of these two genera in relation to the effects of mixed IRB populations on kinetic control of mineralogical Fe (oxyhydr)oxides reductive dissolution. Laboratory experiments were carried out with two freshly synthetized Fe (oxyhydr)oxides presenting contrasting specific surfaces, and two defined Fe-oxides, i.e., goethite and hematite. Three IRB consortia were enriched from environmental samples from a riverbank subjected to cyclic redox oscillations related to flooding periods (Decize, France): an unsaturated surface soil, a flooded surface soil and an aquatic sediment, with a mixture of organic compounds provided as electron donors. The consortia could all reduce iron-nitrilotriacetate acid (Fe(III)-NTA) in 1–2 days. When grown on Fe (oxyhydr)oxides, Fe solubilization rates decreased as follows: fresh Fe (oxyhydr)oxides > goethite > hematite. Based on a bacterial rrs gene fingerprinting approach (CE-SSCP), bacterial community structure in presence of Fe(III)-minerals was similar to those of the site sample communities from which they originated but differed from that of the Fe(III)-NTA enrichments. Shewanella was more abundant than Geobacter in all cultures. Its abundance was higher in presence of the most efficiently reduced Fe (oxyhydr)oxide than with other Fe(III)-minerals. Geobacter as a proportion of the total community was highest in the presence of the least easily solubilized Fe (oxyhydr)oxides. This study highlights the influence of Fe mineralogy on the abundance of Geobacter and Shewanella in relation to Fe bio-reduction kinetics in presence of a complex mixture of electron donors.
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Affiliation(s)
- Fengfeng Zhang
- Univ. Orléans, CNRS, BRGM, ISTO, UMR 7327, Orléans, France.,BRGM, Orléans, France
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20
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Galili N, Shemesh A, Yam R, Brailovsky I, Sela-Adler M, Schuster EM, Collom C, Bekker A, Planavsky N, Macdonald FA, Préat A, Rudmin M, Trela W, Sturesson U, Heikoop JM, Aurell M, Ramajo J, Halevy I. The geologic history of seawater oxygen isotopes from marine iron oxides. Science 2020; 365:469-473. [PMID: 31371609 DOI: 10.1126/science.aaw9247] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Accepted: 07/02/2019] [Indexed: 11/02/2022]
Abstract
The oxygen isotope composition (δ18O) of marine sedimentary rocks has increased by 10 to 15 per mil since Archean time. Interpretation of this trend is hindered by the dual control of temperature and fluid δ18O on the rocks' isotopic composition. A new δ18O record in marine iron oxides covering the past ~2000 million years shows a similar secular rise. Iron oxide precipitation experiments reveal a weakly temperature-dependent iron oxide-water oxygen isotope fractionation, suggesting that increasing seawater δ18O over time was the primary cause of the long-term rise in δ18O values of marine precipitates. The 18O enrichment may have been driven by an increase in terrestrial sediment cover, a change in the proportion of high- and low-temperature crustal alteration, or a combination of these and other factors.
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Affiliation(s)
- Nir Galili
- Department of Earth and Planetary Sciences, Weizmann Institute of Science, Rehovot, Israel.
| | - Aldo Shemesh
- Department of Earth and Planetary Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Ruth Yam
- Department of Earth and Planetary Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Irena Brailovsky
- Department of Earth and Planetary Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Michal Sela-Adler
- Department of Earth and Planetary Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Elaine M Schuster
- Department of Earth and Planetary Sciences, Weizmann Institute of Science, Rehovot, Israel
| | | | - Andrey Bekker
- Department of Earth Sciences, University of California, Riverside, CA, USA
| | - Noah Planavsky
- Department of Geology and Geophysics, Yale University, New Haven, CT, USA
| | - Francis A Macdonald
- Department of Earth Science, University of California, Santa Barbara, CA, USA
| | - Alain Préat
- Department of Biogeochemistry and Modeling of the Earth System, University of Brussels, Brussels, Belgium
| | - Maxim Rudmin
- Division for Geology, Tomsk Polytechnic University, Tomsk, Russia
| | | | - Ulf Sturesson
- The Institute of Earth Sciences, Uppsala University, Uppsala, Sweden
| | - Jeffrey M Heikoop
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM, USA
| | - Marcos Aurell
- Department of Earth Sciences, University of Zaragoza, Zaragoza, Spain
| | - Javier Ramajo
- Department of Earth Sciences, University of Zaragoza, Zaragoza, Spain
| | - Itay Halevy
- Department of Earth and Planetary Sciences, Weizmann Institute of Science, Rehovot, Israel.
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21
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Oleinikova OV, Poitrasson F, Drozdova OY, Shirokova LS, Lapitskiy SA, Pokrovsky OS. Iron Isotope Fractionation during Bio- and Photodegradation of Organoferric Colloids in Boreal Humic Waters. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:11183-11194. [PMID: 31483618 DOI: 10.1021/acs.est.9b02797] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Biodegradation and photolysis of dissolved organic matter (DOM) in boreal high-latitude waters are the two main factors controlling not only the aquatic fluxes and residence time of carbon but also metal nutrients associated with DOM such as Fe. The DOM is usually present in the form of organic and organomineral colloids, which also account for the majority of dissolved Fe. Here, we use the stable Fe isotope approach to unravel the processes controlling Fe behavior during bio- and photodegradation of colloids in boreal Fe- and DOM-rich humic waters (a stream and a fen). The adsorption of Fe colloids onto heterotrophic bacteria Pseudomonas aureofaciens produced enrichment in +0.4‰ (δ57Fe) in the heavier isotopes of the cell surface relative to the remaining solution. In contrast, long-term assimilation of Fe by live cells yielded preferential incorporation of lighter isotopes into the cells (-0.7‰ relative to aqueous solution). The sunlight-induced oxidation of Fe(II) in fen water led to the removal of heavier Fe isotopes (+1.5 to +2.5‰) from solution, consistent with Fe(III) hydroxide precipitation from Fe(II)-bearing solution. Altogether, bio- and photodegradation of organoferric colloids, occurring within a few days of exposure time, can produce several per mil isotopic excursions in shallow lentic and lothic inland waters of high-latitude boreal regions. Considerable daily scale variations of Fe isotopic composition should therefore be taken into account during the interpretation of the riverine flux of Fe isotopes to the ocean or tracing weathering processes using Fe isotopes in surface waters at high latitudes.
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Affiliation(s)
- Olga V Oleinikova
- Geosciences and Environment Toulouse (GET), UMR 5563 CNRS , 14 Avenue Edouard Belin , 31400 Toulouse , France
| | - Franck Poitrasson
- Geosciences and Environment Toulouse (GET), UMR 5563 CNRS , 14 Avenue Edouard Belin , 31400 Toulouse , France
| | - Olga Yu Drozdova
- Geological Faculty of Moscow State University , 1 Leninskie Gory , 119234 Moscow , Russia
| | - Liudmila S Shirokova
- Geosciences and Environment Toulouse (GET), UMR 5563 CNRS , 14 Avenue Edouard Belin , 31400 Toulouse , France
- N. Laverov Federal Center for Integrated Arctic Research , Russian Academy of Science , 23 Naberezhnaya Sev Dviny , 163000 Arkhangelsk , Russia
| | - Sergey A Lapitskiy
- Geological Faculty of Moscow State University , 1 Leninskie Gory , 119234 Moscow , Russia
| | - Oleg S Pokrovsky
- Geosciences and Environment Toulouse (GET), UMR 5563 CNRS , 14 Avenue Edouard Belin , 31400 Toulouse , France
- N. Laverov Federal Center for Integrated Arctic Research , Russian Academy of Science , 23 Naberezhnaya Sev Dviny , 163000 Arkhangelsk , Russia
- BIO-GEO-CLIM Laboratory , Tomsk State University , 36 Lenina Avenue , 634050 Tomsk , Russia
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22
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Notini L, Byrne JM, Tomaszewski EJ, Latta DE, Zhou Z, Scherer MM, Kappler A. Mineral Defects Enhance Bioavailability of Goethite toward Microbial Fe(III) Reduction. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:8883-8891. [PMID: 31284712 DOI: 10.1021/acs.est.9b03208] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Surface defects have been shown to facilitate electron transfer between Fe(II) and goethite (α-FeOOH) in abiotic systems. It is unclear, however, whether defects also facilitate microbial goethite reduction in anoxic environments where electron transfer between cells and Fe(III) minerals is the limiting factor. Here, we used stable Fe isotopes to differentiate microbial reduction of goethite synthesized by hydrolysis from reduction of goethite that was further hydrothermally treated to remove surface defects. The goethites were reduced by Geobacter sulfurreducens in the presence of an external electron shuttle, and we used ICP-MS to distinguish Fe(II) produced from the reduction of the two types of goethite. When reduced separately, goethite with more defects has an initial rate of Fe(III) reduction about 2-fold higher than goethite containing fewer defects. However, when reduced together, the initial rate of reduction is 6-fold higher for goethite with more defects. Our results suggest that there is a suppression of the reduction of goethite with fewer defects in favor of the reduction of minerals with more defects. In the environment, minerals are likely to contain defects and our data demonstrates that even small changes at the surface of iron minerals may change their bioavailability and determine which minerals will be reduced.
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Affiliation(s)
- Luiza Notini
- Department of Civil and Environmental Engineering , University of Iowa , Iowa City , Iowa 52242 , United States
| | - James M Byrne
- Geomicrobiology Group, Centre for Applied Geosciences (ZAG) , University of Tübingen , Sigwartstrasse 10 , D-72076 , Tübingen , Germany
| | - Elizabeth J Tomaszewski
- Geomicrobiology Group, Centre for Applied Geosciences (ZAG) , University of Tübingen , Sigwartstrasse 10 , D-72076 , Tübingen , Germany
| | - Drew E Latta
- Department of Civil and Environmental Engineering , University of Iowa , Iowa City , Iowa 52242 , United States
| | - Zhe Zhou
- Department of Civil and Environmental Engineering , University of Iowa , Iowa City , Iowa 52242 , United States
| | - Michelle M Scherer
- Department of Civil and Environmental Engineering , University of Iowa , Iowa City , Iowa 52242 , United States
| | - Andreas Kappler
- Geomicrobiology Group, Centre for Applied Geosciences (ZAG) , University of Tübingen , Sigwartstrasse 10 , D-72076 , Tübingen , Germany
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23
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Huang J, Wang Q, Wang Z, Zhang H. Interactions and Reductive Reactivity in Ternary Mixtures of Fe(II), Goethite, and Phthalic Acid Based on a Combined Experimental and Modeling Approach. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:8220-8227. [PMID: 31140818 DOI: 10.1021/acs.langmuir.9b00538] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The interactions between organic ligands, Fe(II), and iron oxides are important in biogeochemical redox processes. The effect of phthalic acid (PHA) on the reductive reactivity of Fe(II) associated with goethite was examined using batch adsorption and kinetic studies, attenuated total reflectance?Fourier transform infrared spectroscopy (ATR?FTIR), and surface complexation modeling (SCM). PHA significantly inhibited the reductive reactivity of Fe(II)/goethite, as quantified by the pseudo-first-order reduction rate constants ( k) of p-cyanonitrobenzene. The k value decreased from 1.68 ? 0.03 to 0.338 ? 0.14 h?1 at pH 6.0 as the PHA concentration increased from 0 to 1000 ?M. The effects of the co-adsorption of Fe(II) and PHA onto goethite were then investigated to study the inhibition mechanism. The adsorption experiments showed that Fe(II) slightly enhanced PHA adsorption, whereas PHA did not affect Fe(II) adsorption, suggesting that the inhibition was not due to different amounts of Fe(II) adsorbed. The ATR?FTIR spectra of the adsorbed PHA in the ternary mixtures demonstrated that the major surface species was outer-sphere species, with minor inner-sphere complexes formed. SCM results showed that the presence of PHA (L) led to the formation of a type A ternary species ((?FeOFe+)2???L2?) on the goethite surface, decreasing the abundance of the reactive species (?FeOFeOH). Moreover, the adsorption of PHA on the surface of goethite might block the reactive sites and inhibit the electron transfer between Fe(II) and goethite, thus decreasing the reactivity. Overall, these findings provided new insights into the reaction mechanisms of surface-adsorbed Fe(II), which will facilitate the development of new technologies for site remediation and more accurate risk assessment.
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Affiliation(s)
- Jianzhi Huang
- Department of Civil Engineering , Case Western Reserve University , Cleveland , Ohio 44106-7220 , United States
| | - Qihuang Wang
- Department of Environmental Science and Engineering , Fudan University , Shanghai 200086 , China
| | - Zimeng Wang
- Department of Environmental Science and Engineering , Fudan University , Shanghai 200086 , China
- Shanghai Institute of Pollution Control and Ecological Security , Shanghai 200092 , China
| | - Huichun Zhang
- Department of Civil Engineering , Case Western Reserve University , Cleveland , Ohio 44106-7220 , United States
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24
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Huhmann BL, Neumann A, Boyanov MI, Kemner KM, Scherer MM. Emerging investigator series: As(v) in magnetite: incorporation and redistribution. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2017; 19:1208-1219. [PMID: 28871292 DOI: 10.1039/c7em00237h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Exposure to As in groundwater negatively impacts millions of people around the globe, and As mobility in groundwater is often controlled by Fe mineral dissolution and precipitation. Additionally, trace elements can be released from and incorporated into the structure of Fe oxides in the presence of dissolved Fe(ii). The potential for As to redistribute between sorbed on the magnetite surface and incorporated in the magnetite structure, however, remains unclear. In this study, we use selective chemical extraction and X-ray absorption spectroscopy (XAS) to distinguish magnetite-sorbed and incorporated As(v) and to provide evidence for As(v) incorporation during magnetite precipitation. While As in the As-magnetite coprecipitates did not redistribute between sorbed and incorporated over a 4 month period, a small, but measurable increase in incorporated As(v) of up to 13% was observed for sorbed As(v). We suggest that Fe(ii)-catalyzed recrystallization of magnetite did not significantly influence the redistribution of sorbed As(v) because the extent of Fe atom exchange was small (∼10%). In addition, the extent of As redistribution was the same in the absence and presence of added aqueous Fe(ii), suggesting that aqueous Fe(ii) had, overall, a minor effect on As redistribution for both coprecipitated and sorbed As(v). Our results suggest that coprecipitation of As(v) with magnetite and redistribution of As(v) sorbed on magnetite are potential pathways for irreversible As(v) uptake and sequestration. These pathways are likely to play a significant role in controlling As mobility in natural systems, during human-induced redox cycling of groundwater such as aquifer storage and recovery, as well as in iron oxide-based As removal systems.
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Affiliation(s)
- Brittany L Huhmann
- Department of Civil and Environmental Engineering, University of Iowa, Iowa City, IA 52242, USA
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25
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Swanner ED, Bayer T, Wu W, Hao L, Obst M, Sundman A, Byrne JM, Michel FM, Kleinhanns IC, Kappler A, Schoenberg R. Iron Isotope Fractionation during Fe(II) Oxidation Mediated by the Oxygen-Producing Marine Cyanobacterium Synechococcus PCC 7002. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:4897-4906. [PMID: 28402123 PMCID: PMC5415872 DOI: 10.1021/acs.est.6b05833] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Revised: 04/10/2017] [Accepted: 04/12/2017] [Indexed: 06/07/2023]
Abstract
In this study, we couple iron isotope analysis to microscopic and mineralogical investigation of iron speciation during circumneutral Fe(II) oxidation and Fe(III) precipitation with photosynthetically produced oxygen. In the presence of the cyanobacterium Synechococcus PCC 7002, aqueous Fe(II) (Fe(II)aq) is oxidized and precipitated as amorphous Fe(III) oxyhydroxide minerals (iron precipitates, Feppt), with distinct isotopic fractionation (ε56Fe) values determined from fitting the δ56Fe(II)aq (1.79‰ and 2.15‰) and the δ56Feppt (2.44‰ and 2.98‰) data trends from two replicate experiments. Additional Fe(II) and Fe(III) phases were detected using microscopy and chemical extractions and likely represent Fe(II) and Fe(III) sorbed to minerals and cells. The iron desorbed with sodium acetate (FeNaAc) yielded heavier δ56Fe compositions than Fe(II)aq. Modeling of the fractionation during Fe(III) sorption to cells and Fe(II) sorption to Feppt, combined with equilibration of sorbed iron and with Fe(II)aq using published fractionation factors, is consistent with our resulting δ56FeNaAc. The δ56Feppt data trend is inconsistent with complete equilibrium exchange with Fe(II)aq. Because of this and our detection of microbially excreted organics (e.g., exopolysaccharides) coating Feppt in our microscopic analysis, we suggest that electron and atom exchange is partially suppressed in this system by biologically produced organics. These results indicate that cyanobacteria influence the fate and composition of iron in sunlit environments via their role in Fe(II) oxidation through O2 production, the capacity of their cell surfaces to sorb iron, and the interaction of secreted organics with Fe(III) minerals.
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Affiliation(s)
- E. D. Swanner
- Iowa
State University, Department of Geological
& Atmospheric Sciences, 2237 Osborn Drive, 253 Science I, Ames, Iowa 50011-1027, United States
| | - T. Bayer
- University
of Tuebingen, Department of Geosciences, Tuebingen, Germany
| | - W. Wu
- University
of Tuebingen, Department of Geosciences, Tuebingen, Germany
| | - L. Hao
- University
of Tuebingen, Department of Geosciences, Tuebingen, Germany
| | - M. Obst
- University
of Bayreuth, Bayreuth Center of Ecology
and Environmental Research, Dr-Hans-Frisch-Str. 1-3, 95448 Bayreuth, Germany
| | - A. Sundman
- University
of Tuebingen, Department of Geosciences, Tuebingen, Germany
| | - J. M. Byrne
- University
of Tuebingen, Department of Geosciences, Tuebingen, Germany
| | - F. M. Michel
- Department
of Geosciences, Virginia Tech, Blacksburg, Virginia 24061-0420, United States
| | - I. C. Kleinhanns
- University
of Tuebingen, Department of Geosciences, Tuebingen, Germany
| | - A. Kappler
- University
of Tuebingen, Department of Geosciences, Tuebingen, Germany
| | - R. Schoenberg
- University
of Tuebingen, Department of Geosciences, Tuebingen, Germany
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26
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Fe Isotopic Compositions of Modern Seafloor Hydrothermal Systems and Their Influence Factors. J CHEM-NY 2017. [DOI: 10.1155/2017/1417302] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Based on previous research on the Fe isotope compositions of various components and systems of the Earth, this study focused on the Fe isotope compositions of hydrothermal systems, including the Fe isotope variations in chalcopyrite, pyrite, and sphalerite, and their possible controlling factors. The main findings are as follows: (1) The range of Fe isotopes in hydrothermal systems at mid-ocean ridge is very large. The δ56Fe values of hydrothermal fluids are characterized by significant enrichment in light Fe isotopes. (2) The δ56Fe values of sulfides also exhibit lighter Fe isotope characteristics than those of hydrothermal fluids from hydrothermal vent fields at mid-ocean ridge. The vent temperature, fluid properties, and mineral deposition processes significantly affect the δ56Fe values of hydrothermal sulfides. (3) Chalcopyrite is preferentially enriched in heavy Fe isotopes, whereas sphalerite and pyrite are enriched in light Fe isotopes. In addition, the δ56Fe values of pyrite/marcasite display a larger range than those of chalcopyrite. This pattern is directly related to equilibrium fractionation or kinetic fractionation of Fe isotopes during the deposition of sulfides. To better understand the Fe isotope compositions of modern seafloor hydrothermal systems, the geochemical behavior and fractionation mechanisms of Fe isotopes require further in situ study.
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27
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Garnier J, Garnier JM, Vieira CL, Akerman A, Chmeleff J, Ruiz RI, Poitrasson F. Iron isotope fingerprints of redox and biogeochemical cycling in the soil-water-rice plant system of a paddy field. THE SCIENCE OF THE TOTAL ENVIRONMENT 2017; 574:1622-1632. [PMID: 27697337 DOI: 10.1016/j.scitotenv.2016.08.202] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2016] [Revised: 08/29/2016] [Accepted: 08/30/2016] [Indexed: 06/06/2023]
Abstract
The iron isotope composition was used to investigate dissimilatory iron reduction (DIR) processes in an iron-rich waterlogged paddy soil, the iron uptake strategies of plants and its translocation in the different parts of the rice plant along its growth. Fe concentration and isotope composition (δ56Fe) in irrigation water, precipitates from irrigation water, soil, pore water solution at different depths under the surface water, iron plaque on rice roots, rice roots, stems, leaves and grains were measured. Over the 8.5-10cm of the vertical profiles investigated, the iron pore water concentration (0.01 to 24.3mg·l-1) and δ56Fe (-0.80 to -3.40‰) varied over a large range. The significant linear co-variation between Ln[Fe] and δ56Fe suggests an apparent Rayleigh-type behavior of the DIR processes. An average net fractionation factor between the pore water and the soil substrate of Δ56Fe≈-1.15‰ was obtained, taking the average of all the δ56Fe values weighted by the amount of Fe for each sample. These results provide a robust field study confirmation of the conceptual model of Crosby et al. (2005, 2007) for interpreting the iron isotope fractionation observed during DIR, established from a series of laboratories experiments. In addition, the strong enrichment of heavy Fe isotope measured in the root relative to the soil solution suggest that the iron uptake by roots is more likely supplied by iron from plaque and not from the plant-available iron in the pore water. Opposite to what was previously observed for plants following strategy II for iron uptake from soils, an iron isotope fractionation factor of -0.9‰ was found from the roots to the rice grains, pointing to isotope fractionation during rice plant growth. All these features highlight the insights iron isotope composition provides into the biogeochemical Fe cycling in the soil-water-rice plant systems studied in nature.
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Affiliation(s)
- J Garnier
- Instituto de Geociências, Universidade de Brasilia, IG/GMP-ICC Centro, 70919-970 Brasilia-DF, Brazil; Laboratoire Mixte International, LMI OCE « Observatoire des changements Environnementaux », Institut de Recherche pour le Développement/University of Brasilia, Campus Darcy Ribeiro, Brasilia, Brazil
| | - J-M Garnier
- Centre Européen de Recherche et d'Enseignement des Géosciences de l'Environnement (CEREGE), UMR CNRS 7730, AMU (Aix-Marseille Université), BP 80, 13545 Aix en Provence, France.
| | - C L Vieira
- Instituto de Geociências, Universidade de Brasilia, IG/GMP-ICC Centro, 70919-970 Brasilia-DF, Brazil; Laboratoire Mixte International, LMI OCE « Observatoire des changements Environnementaux », Institut de Recherche pour le Développement/University of Brasilia, Campus Darcy Ribeiro, Brasilia, Brazil
| | - A Akerman
- Laboratoire Geosciences Environnement Toulouse, UMR 5563 CNRS - UPS - IRD, 14, Avenue Edouard Belin, 31400 Toulouse, France
| | - J Chmeleff
- Laboratoire Geosciences Environnement Toulouse, UMR 5563 CNRS - UPS - IRD, 14, Avenue Edouard Belin, 31400 Toulouse, France
| | - R I Ruiz
- Institute of Geosciences, University of São Paulo, rua do Lago, 562, São Paulo 05508-080, Brazil
| | - F Poitrasson
- Laboratoire Geosciences Environnement Toulouse, UMR 5563 CNRS - UPS - IRD, 14, Avenue Edouard Belin, 31400 Toulouse, France
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28
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Shi B, Liu K, Wu L, Li W, Smeaton CM, Beard BL, Johnson CM, Roden EE, Van Cappellen P. Iron Isotope Fractionations Reveal a Finite Bioavailable Fe Pool for Structural Fe(III) Reduction in Nontronite. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:8661-8669. [PMID: 27291525 DOI: 10.1021/acs.est.6b02019] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We report on stable Fe isotope fractionation during microbial and chemical reduction of structural Fe(III) in nontronite NAu-1. (56)Fe/(54)Fe fractionation factors between aqueous Fe(II) and structural Fe(III) ranged from -1.2 to +0.8‰. Microbial (Shewanella oneidensis and Geobacter sulfurreducens) and chemical (dithionite) reduction experiments revealed a two-stage process. Stage 1 was characterized by rapid reduction of a finite Fe(III) pool along the edges of the clay particles, accompanied by a limited release to solution of Fe(II), which partially adsorbed onto basal planes. Stable Fe isotope compositions revealed that electron transfer and atom exchange (ETAE) occurred between edge-bound Fe(II) and octahedral (structural) Fe(III) within the clay lattice, as well as between aqueous Fe(II) and structural Fe(III) via a transient sorbed phase. The isotopic fractionation factors decreased with increasing extent of reduction as a result of the depletion of the finite bioavailable Fe(III) pool. During stage 2, microbial reduction was inhibited while chemical reduction continued. However, further ETAE between aqueous Fe(II) and structural Fe(III) was not observed. Our results imply that the pool of bioavailable Fe(III) is restricted to structural Fe sites located near the edges of the clay particles. Blockage of ETAE distinguishes Fe(III) reduction of layered clay minerals from that of Fe oxyhydroxides, where accumulation of structural Fe(II) is much more limited.
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Affiliation(s)
- Bingjie Shi
- Department of Earth and Environmental Sciences, University of Waterloo , Waterloo, Ontario N2L 3G1, Canada
- Water Institute, University of Waterloo , Waterloo, Ontario N2L 3G1, Canada
| | - Kai Liu
- Department of Earth and Environmental Sciences, University of Waterloo , Waterloo, Ontario N2L 3G1, Canada
- Water Institute, University of Waterloo , Waterloo, Ontario N2L 3G1, Canada
| | - Lingling Wu
- Department of Earth and Environmental Sciences, University of Waterloo , Waterloo, Ontario N2L 3G1, Canada
- Water Institute, University of Waterloo , Waterloo, Ontario N2L 3G1, Canada
| | - Weiqiang Li
- Department of Geoscience, University of Wisconsin-Madison , Madison, Wisconsin 53706, United States
- NASA Astrobiology Institute, University of Wisconsin-Madison , Madison, Wisconsin 53706, United States
| | - Christina M Smeaton
- Department of Earth and Environmental Sciences, University of Waterloo , Waterloo, Ontario N2L 3G1, Canada
- Water Institute, University of Waterloo , Waterloo, Ontario N2L 3G1, Canada
| | - Brian L Beard
- Department of Geoscience, University of Wisconsin-Madison , Madison, Wisconsin 53706, United States
- NASA Astrobiology Institute, University of Wisconsin-Madison , Madison, Wisconsin 53706, United States
| | - Clark M Johnson
- Department of Geoscience, University of Wisconsin-Madison , Madison, Wisconsin 53706, United States
- NASA Astrobiology Institute, University of Wisconsin-Madison , Madison, Wisconsin 53706, United States
| | - Eric E Roden
- Department of Geoscience, University of Wisconsin-Madison , Madison, Wisconsin 53706, United States
- NASA Astrobiology Institute, University of Wisconsin-Madison , Madison, Wisconsin 53706, United States
| | - Philippe Van Cappellen
- Department of Earth and Environmental Sciences, University of Waterloo , Waterloo, Ontario N2L 3G1, Canada
- Water Institute, University of Waterloo , Waterloo, Ontario N2L 3G1, Canada
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29
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Amor M, Busigny V, Louvat P, Gelabert A, Cartigny P, Durand-Dubief M, Ona-Nguema G, Alphandery E, Chebbi I, Guyot F. Mass-dependent and -independent signature of Fe isotopes in magnetotactic bacteria. Science 2016; 352:705-8. [DOI: 10.1126/science.aad7632] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Accepted: 03/28/2016] [Indexed: 12/18/2022]
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30
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Fortney NW, He S, Converse BJ, Beard BL, Johnson CM, Boyd ES, Roden EE. Microbial Fe(III) oxide reduction potential in Chocolate Pots hot spring, Yellowstone National Park. GEOBIOLOGY 2016; 14:255-275. [PMID: 26750514 DOI: 10.1111/gbi.12173] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Accepted: 11/10/2015] [Indexed: 06/05/2023]
Abstract
Chocolate Pots hot springs (CP) is a unique, circumneutral pH, iron-rich, geothermal feature in Yellowstone National Park. Prior research at CP has focused on photosynthetically driven Fe(II) oxidation as a model for mineralization of microbial mats and deposition of Archean banded iron formations. However, geochemical and stable Fe isotopic data have suggested that dissimilatory microbial iron reduction (DIR) may be active within CP deposits. In this study, the potential for microbial reduction of native CP Fe(III) oxides was investigated, using a combination of cultivation dependent and independent approaches, to assess the potential involvement of DIR in Fe redox cycling and associated stable Fe isotope fractionation in the CP hot springs. Endogenous microbial communities were able to reduce native CP Fe(III) oxides, as documented by most probable number enumerations and enrichment culture studies. Enrichment cultures demonstrated sustained DIR driven by oxidation of acetate, lactate, and H2 . Inhibitor studies and molecular analyses indicate that sulfate reduction did not contribute to observed rates of DIR in the enrichment cultures through abiotic reaction pathways. Enrichment cultures produced isotopically light Fe(II) during DIR relative to the bulk solid-phase Fe(III) oxides. Pyrosequencing of 16S rRNA genes from enrichment cultures showed dominant sequences closely affiliated with Geobacter metallireducens, a mesophilic Fe(III) oxide reducer. Shotgun metagenomic analysis of enrichment cultures confirmed the presence of a dominant G. metallireducens-like population and other less dominant populations from the phylum Ignavibacteriae, which appear to be capable of DIR. Gene (protein) searches revealed the presence of heat-shock proteins that may be involved in increased thermotolerance in the organisms present in the enrichments as well as porin-cytochrome complexes previously shown to be involved in extracellular electron transport. This analysis offers the first detailed insight into how DIR may impact the Fe geochemistry and isotope composition of a Fe-rich, circumneutral pH geothermal environment.
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Affiliation(s)
- N W Fortney
- Department of Geoscience, NASA Astrobiology Institute, University of Wisconsin-Madison, Madison, WI, USA
| | - S He
- Department of Geoscience, NASA Astrobiology Institute, University of Wisconsin-Madison, Madison, WI, USA
| | - B J Converse
- Department of Geoscience, NASA Astrobiology Institute, University of Wisconsin-Madison, Madison, WI, USA
| | - B L Beard
- Department of Geoscience, NASA Astrobiology Institute, University of Wisconsin-Madison, Madison, WI, USA
| | - C M Johnson
- Department of Geoscience, NASA Astrobiology Institute, University of Wisconsin-Madison, Madison, WI, USA
| | - E S Boyd
- Department of Microbiology and Immunology, NASA Astrobiology Institute, Montana State University, Bozeman, MT, USA
| | - E E Roden
- Department of Geoscience, NASA Astrobiology Institute, University of Wisconsin-Madison, Madison, WI, USA
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Mulholland DS, Poitrasson F, Boaventura GR. Effects of different water storage procedures on the dissolved Fe concentration and isotopic composition of chemically contrasted waters from the Amazon River Basin. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2015; 29:2102-2108. [PMID: 26443413 DOI: 10.1002/rcm.7368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Revised: 08/18/2015] [Accepted: 08/20/2015] [Indexed: 06/05/2023]
Abstract
RATIONALE Although recent studies have investigated the Fe isotopic composition of dissolved, colloidal and particulate phases from continental and oceanic natural waters, few efforts have been made to evaluate whether water sample storage and the separation of different pore-size fractions through filtration can cause any change to the Fe isotopic compositions. The present study investigates the possible biases introduced by different water storage conditions on the dissolved Fe concentration and isotopic composition of chemically different waters. METHODS Water samples were collected from an organic-rich river and from mineral particulate-rich rivers. Filtered and unfiltered water samples were stored either at room temperature or frozen at -18°C in order to assess possible biases due to (i) different water storage temperature, and (ii) storage of bulk (unfiltered) vs filtered water. Iron isotope measurements were performed by Multicollector Inductively Coupled Plasma Mass Spectrometry with a Thermo Electron Neptune instrument, after Fe purification using anion-exchange resins. RESULTS Our data reveal that bulk water storage at room temperature without filtration produces minor changes in the dissolved Fe isotopic composition of mineral particulate-rich waters, but significant isotopic composition changes in organic-rich waters. In both cases, however, the impact of the different procedures on the Fe concentrations was strong. On the other hand, the bulk water stored frozen without filtration produced more limited changes in the dissolved Fe concentrations, and also on isotopic compositions, relative to the samples filtered in the field. The largest effect was again observed for the organic-rich waters. CONCLUSIONS These findings suggest that a time lag between water collection and filtration may cause isotopic exchanges between the dissolved and particulate Fe fractions. When it is not possible to filter the samples in the field immediately after collection, the less detrimental approach is to freeze the bulk water sample until filtration, to reduce isotopic artifacts.
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Affiliation(s)
- Daniel S Mulholland
- Instituto de Geociências, Universidade de Brasília, Campus Darcy Ribeiro, 70910-900, Brasília, Brazil
- Laboratoire Géosciences Environnement Toulouse, Institut de Recherches pour le Développement - Centre National de la Recherche Scientifique, Université de Toulouse, 14-16 avenue Edouard Belin, 31400, Toulouse, France
| | - Franck Poitrasson
- Instituto de Geociências, Universidade de Brasília, Campus Darcy Ribeiro, 70910-900, Brasília, Brazil
- Laboratoire Géosciences Environnement Toulouse, Institut de Recherches pour le Développement - Centre National de la Recherche Scientifique, Université de Toulouse, 14-16 avenue Edouard Belin, 31400, Toulouse, France
| | - Geraldo R Boaventura
- Instituto de Geociências, Universidade de Brasília, Campus Darcy Ribeiro, 70910-900, Brasília, Brazil
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Chen C, Kukkadapu R, Sparks DL. Influence of Coprecipitated Organic Matter on Fe2+(aq)-Catalyzed Transformation of Ferrihydrite: Implications for Carbon Dynamics. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2015; 49:10927-36. [PMID: 26260047 DOI: 10.1021/acs.est.5b02448] [Citation(s) in RCA: 106] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Aqueous Fe(II) is known to catalyze the abiotic transformation of ferrihydrite to more stable Fe minerals. However, little is known about the impacts of coprecipitated OM on Fe(II)-catalyzed ferrihydrite transformation and its consequences for C dynamics. Accordingly, we investigated the extent and pathway of Fe(II)-induced transformation of OM-ferrihydrite coprecipitates as a function of C/Fe ratios and aqueous Fe(II) concentrations, and its implications for subsequent C dynamics. The coprecipitated OM resulted in a linear decrease in ferrihydrite transformation with increasing C/Fe ratios. The secondary mineral profiles upon Fe(II) reaction with OM-ferrihydrite coprecipitates depend on Fe(II) concentrations At 0.2 mM Fe(II), OM completely inhibited goethite formation and stimulated lepidocrocite formation. At 2 mM Fe(II), whereas goethite was formed in the presence of OM, OM reduced the amount of goethite and magnetite formation and increased the formation of lepidocrocite. The solid-phase C content remained unchanged after reaction, suggesting that OM remains associated with Fe minerals following ferrihydrite transformation to more stable Fe minerals. However, C desorbability by H2PO4(-) from the resulting Fe minerals following reaction was enhanced. The study indicates a "lepidocrocite favoring effect" by OM and suggests that Fe(II)-catalyzed transformation of ferrihydrite may decrease OM stability in natural environments under moderately reducing conditions.
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Affiliation(s)
- Chunmei Chen
- Department of Plant and Soil Sciences, Delaware Environmental Institute, University of Delaware , Newark, Delaware 19711, United States
| | - Ravi Kukkadapu
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory , Richland, Washington 99354, United States
| | - Donald L Sparks
- Department of Plant and Soil Sciences, Delaware Environmental Institute, University of Delaware , Newark, Delaware 19711, United States
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Frierdich AJ, Helgeson M, Liu C, Wang C, Rosso KM, Scherer MM. Iron Atom Exchange between Hematite and Aqueous Fe(II). ENVIRONMENTAL SCIENCE & TECHNOLOGY 2015; 49:8479-86. [PMID: 26069932 DOI: 10.1021/acs.est.5b01276] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Aqueous Fe(II) has been shown to exchange with structural Fe(III) in goethite without any significant phase transformation. It remains unclear, however, whether aqueous Fe(II) undergoes similar exchange reactions with structural Fe(III) in hematite, a ubiquitous iron oxide mineral. Here, we use an enriched (57)Fe tracer to show that aqueous Fe(II) exchanges with structural Fe(III) in hematite at room temperature, and that the amount of exchange is influenced by particle size, pH, and Fe(II) concentration. Reaction of 80 nm-hematite (27 m(2) g(-1)) with aqueous Fe(II) at pH 7.0 for 30 days results in ∼5% of its structural Fe(III) atoms exchanging with Fe(II) in solution, which equates to about one surface iron layer. Smaller, 50 nm-hematite particles (54 m(2) g(-1)) undergo about 25% exchange (∼3× surface iron) with aqueous Fe(II), demonstrating that structural Fe(III) in hematite is accessible to the fluid in the presence of Fe(II). The extent of exchange in hematite increases with pH up to 7.5 and then begins to decrease as the pH progresses to 8.0, likely due to surface site saturation by sorbed Fe(II). Similarly, when we vary the initial amount of added Fe(II), we observe decreasing amounts of exchange when aqueous Fe(II) is increased beyond surface saturation. This work shows that Fe(II) can catalyze iron atom exchange between bulk hematite and aqueous Fe(II), despite hematite being the most thermodynamically stable iron oxide.
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Affiliation(s)
- Andrew J Frierdich
- †Department of Civil and Environmental Engineering, University of Iowa, Iowa City, Iowa 52242, United States
- ‡Department of Geoscience, University of Wisconsin, Madison, Wisconsin 53706, United States
| | - Maria Helgeson
- †Department of Civil and Environmental Engineering, University of Iowa, Iowa City, Iowa 52242, United States
| | - Chengshuai Liu
- §Guangdong Institute of Eco-Environmental and Soil Sciences, Guangzhou, 510650, P. R. China
| | - Chongmin Wang
- ∥Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Kevin M Rosso
- ∥Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Michelle M Scherer
- †Department of Civil and Environmental Engineering, University of Iowa, Iowa City, Iowa 52242, United States
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Neumann A, Wu L, Li W, Beard BL, Johnson CM, Rosso KM, Frierdich AJ, Scherer MM. Atom exchange between aqueous Fe(II) and structural Fe in clay minerals. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2015; 49:2786-95. [PMID: 25671351 DOI: 10.1021/es504984q] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Due to their stability toward reductive dissolution, Fe-bearing clay minerals are viewed as a renewable source of Fe redox activity in diverse environments. Recent findings of interfacial electron transfer between aqueous Fe(II) and structural Fe in clay minerals and electron conduction in octahedral sheets of nontronite, however, raise the question whether Fe interaction with clay minerals is more dynamic than previously thought. Here, we use an enriched isotope tracer approach to simultaneously trace Fe atom movement from the aqueous phase to the solid ((57)Fe) and from the solid into the aqueous phase ((56)Fe). Over 6 months, we observed a significant decrease in aqueous (57)Fe isotope fraction, with a fast initial decrease which slowed after 3 days and stabilized after about 50 days. For the aqueous (56)Fe isotope fraction, we observed a similar but opposite trend, indicating that Fe atom movement had occurred in both directions: from the aqueous phase into the solid and from the solid into aqueous phase. We calculated that 5-20% of structural Fe in clay minerals NAu-1, NAu-2, and SWa-1 exchanged with aqueous Fe(II), which significantly exceeds the Fe atom layer exposed directly to solution. Calculations based on electron-hopping rates in nontronite suggest that the bulk conduction mechanism previously demonstrated for hematite1 and suggested as an explanation for the significant Fe atom exchange observed in goethite2 may be a plausible mechanism for Fe atom exchange in Fe-bearing clay minerals. Our finding of 5-20% Fe atom exchange in clay minerals indicates that we need to rethink how Fe mobility affects the macroscopic properties of Fe-bearing phyllosilicates and its role in Fe biogeochemical cycling, as well as its use in a variety of engineered applications, such as landfill liners and nuclear repositories.
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Affiliation(s)
- Anke Neumann
- Civil and Environmental Engineering, The University of Iowa , Iowa City, Iowa 52242, United States
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Yan W, Liu H, Chen R, Xie J, Wei Y. Dissolution and oriented aggregation: transformation from lepidorocite to goethite by the catalysis of aqueous Fe(ii). RSC Adv 2015. [DOI: 10.1039/c5ra19787b] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
At a low temperature, lepidocrocite-to-goethite transformation occurred in the presence of Fe(ii) ions, whereas lepidocrocite was stable in the absence of Fe(ii) ions.
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Affiliation(s)
- Wenjing Yan
- College of Physics Science and Information Engineering
- Hebei Normal University
- Shijiazhuang 050024
- China
- Hebei Chemical and Pharmaceutical College
| | - Hui Liu
- College of Chemistry and Material Science
- Hebei Normal University
- Shijiazhuang 050024
- China
- Key Laboratory of Inorganic Nanomaterial of Hebei Province
| | - Rufen Chen
- College of Chemistry and Material Science
- Hebei Normal University
- Shijiazhuang 050024
- China
- Key Laboratory of Inorganic Nanomaterial of Hebei Province
| | - Juan Xie
- College of Science
- Hebei University of Engineering
- Handan 056038
- China
| | - Yu Wei
- College of Chemistry and Material Science
- Hebei Normal University
- Shijiazhuang 050024
- China
- Key Laboratory of Inorganic Nanomaterial of Hebei Province
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Neil CW, Lee B, Jun YS. Different arsenate and phosphate incorporation effects on the nucleation and growth of iron(III) (Hydr)oxides on quartz. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2014; 48:11883-11891. [PMID: 25232994 DOI: 10.1021/es503251z] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Iron(III) (hydr)oxides play an important role in the geochemical cycling of contaminants in natural and engineered aquatic systems. The ability of iron(III) (hydr)oxides to immobilize contaminants can be related to whether the precipitates form heterogeneously (e.g., at mineral surfaces) or homogeneously in solution. Utilizing grazing incidence small-angle X-ray scattering (GISAXS), we studied heterogeneous iron(III) (hydr)oxide nucleation and growth on quartz substrates for systems containing arsenate and phosphate anions. For the iron(III) only system, the radius of gyration (Rg) of heterogeneously formed precipitates grew from 1.5 to 2.5 (± 1.0) nm within 1 h. For the system containing 10(-5) M arsenate, Rg grew from 3.6 to 6.1 (± 0.5) nm, and for the system containing 10(-5) M phosphate, Rg grew from 2.0 to 4.0 (± 0.2) nm. While the systems containing these oxyanions had more growth, the system containing only iron(III) had the most nucleation events on substrates. Ex situ analyses of homogeneously and heterogeneously formed precipitates indicated that precipitates in the arsenate system had the highest water content and that oxyanions may bridge iron(III) hydroxide polymeric embryos to form a structure similar to ferric arsenate or ferric phosphate. These new findings are important because differences in nucleation and growth rates and particle sizes will impact the number of available reactive sites and the reactivity of newly formed particles toward aqueous contaminants.
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Affiliation(s)
- Chelsea W Neil
- Department of Energy, Environmental and Chemical Engineering, Washington University , St. Louis, Missouri 63130, United States
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Handler RM, Frierdich AJ, Johnson CM, Rosso KM, Beard BL, Wang C, Latta DE, Neumann A, Pasakarnis T, Premaratne WAPJ, Scherer MM. Fe(II)-catalyzed recrystallization of goethite revisited. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2014; 48:11302-11. [PMID: 25248028 DOI: 10.1021/es503084u] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Results from enriched (57)Fe isotope tracer experiments have shown that atom exchange can occur between structural Fe in Fe(III) oxides and aqueous Fe(II) with no formation of secondary minerals or change in particle size or shape. Here we derive a mass balance model to quantify the extent of Fe atom exchange between goethite and aqueous Fe(II) that accounts for different Fe pool sizes. We use this model to reinterpret our previous work and to quantify the influence of particle size and pH on extent of goethite exchange with aqueous Fe(II). Consistent with our previous interpretation, substantial exchange of goethite occurred at pH 7.5 (≈ 90%) and we observed little effect of particle size between nanogoethite (average size of 81 × 11 nm; ≈ 110 m(2)/g) and microgoethite (average size of 590 × 42 nm; ≈ 40 m(2)/g). Despite ≈ 90% of the bulk goethite exchanging at pH 7.5, we found no change in mineral phase, average particle size, crystallinity, or reactivity after reaction with aqueous Fe(II). At a lower pH of 5.0, no net sorption of Fe(II) was observed and significantly less exchange occurred accounting for less than the estimated proportion of surface Fe atoms in the particles. Particle size appears to influence the amount of exchange at pH 5.0 and we suggest that aggregation and surface area may play a role. Results from sequential chemical extractions indicate that (57)Fe accumulates in extracted Fe(III) goethite components. Isotopic compositions of the extracts indicate that a gradient of (57)Fe develops within the goethite with more accumulation of (57)Fe occurring in the more easily extracted Fe(III) that may be nearer to the surface.
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Affiliation(s)
- Robert M Handler
- Sustainable Futures Institute, Michigan Technological University 1400 Townsend Drive, Houghton, Michigan 49931, United States
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Liu Y, Lou J, Li FB, Xu JM, Yu XS, Zhu LA, Wang F. Evaluating oxidation-reduction properties of dissolved organic matter from Chinese milk vetch (Astragalus sinicus L.): a comprehensive multi-parametric study. ENVIRONMENTAL TECHNOLOGY 2014; 35:1916-1927. [PMID: 24956785 DOI: 10.1080/09593330.2014.885586] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Green manuring is a common practice in replenishment of soil organic matter and nutrients in rice paddy field. Owing to the complex interplay of multiple factors, the oxidation--reduction (redox) properties of dissolved organic matter (DOM) from green manure crops are presently not fully understood. In this study, a variety of surrogate parameters were used to evaluate the redox capacity and redox state of DOM derived from Chinese milk vetch (CMV, Astragalus sinicus L.) via microbial decomposition under continuously flooded (CF) and non-flooded (NF) conditions. Additionally, the correlation between the surrogate parameters of CMV-DOM and the kinetic parameters of relevant redox reactions was evaluated in a soil-water system containing CMV-DOM. Results showed that the redox properties of CMV-DOM were substantially different between the fresh and decomposed CMV-DOM treatments. Determination of the surrogate parameters via ultraviolet-visible/Fourier transform infrared absorption spectroscopy and gel permeation chromatography generally provided high-quality data for predicting the redox capacity of CMV-DOM, while the surrogate parameters determined by elemental analysis were suitable for predicting the redox state of CMV-DOM. Depending on the redox capacity and redox state of various moieties/components, NF-decomposed CMV-DOM could easily accelerate soil reduction by shuttling electrons to iron oxides, because it contained more reversible redox-active functional groups (e.g. quinone and hydroquinone pairs) than CF-decomposed CMV-DOM. This work demonstrates that a single index cannot interpret complex changes in multiple factors that jointly determine the redox reactivity of CMV-DOM. Thus, a multi-parametric study is needed for providing comprehensive information on the redox properties of green manure DOM.
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Wu L, Brucker RP, Beard BL, Roden EE, Johnson CM. Iron isotope characteristics of Hot Springs at Chocolate Pots, Yellowstone National Park. ASTROBIOLOGY 2013; 13:1091-1101. [PMID: 24219169 DOI: 10.1089/ast.2013.0996] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Chocolate Pots Hot Springs in Yellowstone National Park is a hydrothermal system that contains high aqueous ferrous iron [∼0.1 mM Fe(II)] at circumneutral pH conditions. This site provides an ideal field environment in which to test our understanding of Fe isotope fractionations derived from laboratory experiments. The Fe(III) oxides, mainly produced through Fe(II) oxidation by oxygen in the atmosphere, have high ⁵⁶Fe/⁵⁴Fe ratios compared with the aqueous Fe(II). However, the degree of fractionation is less than that expected in a closed system at isotopic equilibrium. We suggest two explanations for the observed Fe isotope compositions. One is that light Fe isotopes partition into a sorbed component and precipitate out on the Fe(III) oxide surfaces in the presence of silica. The other explanation is internal regeneration of isotopically heavy Fe(II) via dissimilatory Fe(III) reduction farther down the flow path as well as deeper within the mat materials. These findings provide evidence that silica plays an important role in governing Fe isotope fractionation factors between reduced and oxidized Fe. Under conditions of low ambient oxygen, such as may be found on early Earth or Mars, significantly larger Fe isotope variations are predicted, reflecting the more likely attainment of Fe isotope equilibrium associated with slower oxidation rates under low-O₂ conditions.
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Affiliation(s)
- Lingling Wu
- 1 Department of Geoscience, University of Wisconsin-Madison , Madison, Wisconsin, USA
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Liu Y, Li FB, Xia W, Xu JM, Yu XS. Association between ferrous iron accumulation and pentachlorophenol degradation at the paddy soil-water interface in the presence of exogenous low-molecular-weight dissolved organic carbon. CHEMOSPHERE 2013; 91:1547-1555. [PMID: 23332677 DOI: 10.1016/j.chemosphere.2012.12.040] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2012] [Revised: 12/12/2012] [Accepted: 12/15/2012] [Indexed: 06/01/2023]
Abstract
Fourteen low-molecular-weight organic acids (organic acids) and eight neutral monosaccharides (monosaccharides) were used to investigate the intrinsic link between ferrous iron [Fe(II)] accumulation and pentachlorophenol (PCP) degradation at the paddy soil-floodwater interface. Using logistic curve fitting, significant differences were observed between Fe(II) accumulation with organic acids and monosaccharides. These differences were attributed to large variations in the dissociation constants and the number of carbon atoms per molecule. A significant relationship was observed between the maximum capacity of Fe(II) accumulation and PCP degradation. Correlations were established between environmental variables including PCP, NaOAc-/HCl-extractable Fe(II), water soluble organic carbon (WSOC), anodic peak oxidation potential (Ep) of Fe(II) species, oxidation-reduction potential (ORP), and pH. The increase in pH combined with WSOC consumption caused a decrease in Ep, which greatly enhanced the HCl-extractable Fe(II) accumulation and subsequently contributed to PCP degradation.
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Affiliation(s)
- Yong Liu
- College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
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Xie X, Johnson TM, Wang Y, Lundstrom CC, Ellis A, Wang X, Duan M. Mobilization of arsenic in aquifers from the Datong Basin, China: evidence from geochemical and iron isotopic data. CHEMOSPHERE 2013; 90:1878-1884. [PMID: 23146274 DOI: 10.1016/j.chemosphere.2012.10.012] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2012] [Revised: 09/30/2012] [Accepted: 10/15/2012] [Indexed: 06/01/2023]
Abstract
Iron isotope compositions of various Fe pools in aquifer sediments were measured at a known As-contaminated site in the Datong Basin, China. The δ(56)Fe values of HCl-extracted poor-crystalline Fe(III) range widely from -0.41‰ to 0.36‰. We interpret the low Fe(II)/Fe(Extractable) ratios (<50%) and the negative correlation between Fe(II)/Fe(Extractable) and δ(56)Fe values in HCl-extracted poor-crystalline Fe to be best explained by redox cycling of Fe induced by microbial Fe(III) reduction. However, the high Fe(II)/Fe(Extractable) ratios (~/>70%) and positive correlation between Fe(II)/Fe(Extractable) and δ(56)Fe values for HCl-extracted poor-crystalline Fe indicates production of sulfides (FeSs). The δ(56)Fe values of crystalline Fe(III) extracted by reductant appears to be comparatively small varying from -0.01‰ to 0.24‰, which is consistent with the δ(56)Fe values for ferric oxides/hydroxides having undergone microbial Fe(III) reduction. The Fe isotope composition of various Fe pools shows the transformation between crystalline Fe(III) and poor-crystalline crystalline Fe(III) and the secondary Fe(II) phases has already occurred or is occurring in aquifer sediments. More importantly, there is a significant difference in the As concentrations in crystalline Fe(III) oxides/hydroxides and HCl-extracted Fe phases. The concentrations of As range from 1.6 to 29.9 mg kg(-1) and from 0.6 to 3.0 mg kg(-1), for crystalline Fe(III) and HCl-extracted Fe phases respectively. Accordingly, the transformation of Fe minerals induced by microbial Fe(III) reduction can contribute to the mobilization of As. This study is the first to examine the Fe isotope compositions in high As aquifer sediments; the results show that the Fe isotope would be an important tool in demonstrating the enrichment of As in groundwater.
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Affiliation(s)
- Xianjun Xie
- School of Environmental Studies & State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, 430074 Wuhan, China.
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Abstract
Recent work has indicated that iron (oxyhydr-)oxides are capable of structurally incorporating and releasing metals and nutrients as a result of Fe2+-induced iron oxide recrystallization. In the present paper, we briefly review the current literature examining the mechanisms by which iron oxides recrystallize and summarize how recrystallization affects metal incorporation and release. We also provide new experimental evidence for the Fe2+-induced release of structural manganese from manganese-doped goethite. Currently, the exact mechanism(s) for Fe2+-induced recrystallization remain elusive, although they are likely to be both oxide-and metal-dependent. We conclude by discussing some future research directions for Fe2+-catalysed iron oxide recrystallization.
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Frierdich AJ, Catalano JG. Fe(II)-mediated reduction and repartitioning of structurally incorporated Cu, Co, and Mn in iron oxides. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2012; 46:11070-7. [PMID: 22970760 DOI: 10.1021/es302236v] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The reduction of trace elements and contaminants by Fe(II) at Fe(III) oxide surfaces is well documented. However, the effect of aqueous Fe(II) on the fate of redox-active trace elements structurally incorporated into iron oxides is unknown. Here, we investigate the fate of redox-active elements during Fe(II)-activated recrystallization of Cu-, Co-, and Mn-substituted goethite and hematite. Enhanced release of Cu, Co, and Mn to solution occurs upon exposure of all materials to aqueous Fe(II) relative to reactions in Fe(II)-free fluids. The quantity of trace element release increases with pH when Fe(II) is present but decreases with increasing pH in the absence of Fe(II). Co and Mn release from goethite is predicted well using a second-order kinetic model, consistent with the release of redox-inactive elements such as Ni and Zn. However, Cu release and Co and Mn release from hematite require the sum of two rates to adequately model the kinetic data. Greater uptake of Fe(II) by Cu-, Co-, and Mn-substituted iron oxides relative to analogues containing only redox-inactive elements suggests that net Fe(II) oxidation occurs. Reduction of Cu, Co, and Mn in all materials following reaction with Fe(II) at pHs 7.0-7.5 is confirmed by X-ray absorption near-edge structure spectroscopy. This work shows that redox-sensitive elements structurally incorporated within iron oxides are reduced and repartitioned into fluids during Fe(II)-mediated recrystallization. Such abiotic reactions likely operate in tandem with partial microbial and abiotic iron reduction or during the migration of Fe(II)-containing fluids, mobilizing structurally bound contaminants and micronutrients in aquatic systems.
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Affiliation(s)
- Andrew J Frierdich
- Department of Earth and Planetary Sciences, Washington University, St. Louis, Missouri 63130, USA.
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Xie S, Yang H, Luo G, Huang X, Liu D, Wang Y, Gong Y, Xu R. Geomicrobial functional groups: A window on the interaction between life and environments. CHINESE SCIENCE BULLETIN-CHINESE 2012. [DOI: 10.1007/s11434-011-4860-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Catalano JG, Luo Y, Otemuyiwa B. Effect of aqueous Fe(II) on arsenate sorption on goethite and hematite. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2011; 45:8826-8833. [PMID: 21899306 DOI: 10.1021/es202445w] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Biogeochemical iron cycling often generates systems where aqueous Fe(II) and solid Fe(III) oxides coexist. Reactions between these species result in iron oxide surface and phase transformations, iron isotope fractionation, and redox transformations of many contaminant species. Fe(II)-induced recrystallization of goethite and hematite has recently been shown to cause the repartitioning of Ni(II) at the mineral-water interface, with adsorbed Ni incorporating into the iron oxide structure and preincorporated Ni released back into aqueous solution. However, the effect of Fe(II) on the fate and speciation of redox inactive species incompatible with iron oxide structures is unclear. Arsenate sorption to hematite and goethite in the presence of aqueous Fe(II) was studied to determine whether Fe(II) causes substantial changes in the sorption mechanisms of such incompatible species. Sorption isotherms reveal that Fe(II) minimally alters macroscopic arsenate sorption behavior except at circumneutral pH in the presence of elevated concentrations (10⁻³ M) of Fe(II) and at high arsenate loadings, where a clear signature of precipitation is observed. Powder X-ray diffraction demonstrates that the ferrous arsenate mineral symplesite precipitates under such conditions. Extended X-ray absorption fine structure spectroscopy shows that outside this precipitation regime arsenate surface complexation mechanisms are unaffected by Fe(II). In addition, arsenate was found to suppress Fe(II) sorption through competitive adsorption processes before the onset of symplesite precipitation. This study demonstrates that the sorption of species incompatible with iron oxide structure is not substantially affected by Fe(II) but that such species may potentially interfere with Fe(II)-iron oxide reactions via competitive adsorption.
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Affiliation(s)
- Jeffrey G Catalano
- Department of Earth and Planetary Sciences, Washington University, St. Louis, Missouri 63130, USA.
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Percak-Dennett EM, Beard BL, Xu H, Konishi H, Johnson CM, Roden EE. Iron isotope fractionation during microbial dissimilatory iron oxide reduction in simulated Archaean seawater. GEOBIOLOGY 2011; 9:205-220. [PMID: 21504536 DOI: 10.1111/j.1472-4669.2011.00277.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The largest Fe isotope excursion yet measured in marine sedimentary rocks occurs in shales, carbonates, and banded iron formations of Neoarchaean and Paleoproterozoic age. The results of field and laboratory studies suggest a potential role for microbial dissimilatory iron reduction (DIR) in producing this excursion. However, most experimental studies of Fe isotope fractionation during DIR have been conducted in simple geochemical systems, using pure Fe(III) oxide substrates that are not direct analogues to phases likely to have been present in Precambrian marine environments. In this study, Fe isotope fractionation was investigated during microbial reduction of an amorphous Fe(III) oxide-silica coprecipitate in anoxic, high-silica, low-sulphate artificial Archaean seawater at 30 °C to determine if such conditions alter the extent of reduction or isotopic fractionations relative to those observed in simple systems. The Fe(III)-Si coprecipitate was highly reducible (c. 80% reduction) in the presence of excess acetate. The coprecipitate did not undergo phase conversion (e.g. to green rust, magnetite or siderite) during reduction. Iron isotope fractionations suggest that rapid and near-complete isotope exchange took place among all Fe(II) and Fe(III) components, in contrast to previous work on goethite and hematite, where exchange was limited to the outer few atom layers of the substrate. Large quantities of low-δ(56)Fe Fe(II) (aqueous and solid phase) were produced during reduction of the Fe(III)-Si coprecipitate. These findings shed new light on DIR as a mechanism for producing Fe isotope variations observed in Neoarchaean and Paleoproterozoic marine sedimentary rocks.
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Affiliation(s)
- E M Percak-Dennett
- Department of Geoscience and NASA Astrobiology Institute, University of Wisconsin-Madison, WI, USA
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Gorski CA, Scherer MM. Fe 2+Sorption at the Fe Oxide-Water Interface: A Revised Conceptual Framework. ACS SYMPOSIUM SERIES 2011. [DOI: 10.1021/bk-2011-1071.ch015] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Christopher A. Gorski
- Environmental Chemistry, Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Duebendorf, Switzerland
- Civil and Environmental Engineering, University of Iowa, Iowa City, IA, 52242, USA
| | - Michelle M. Scherer
- Environmental Chemistry, Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Duebendorf, Switzerland
- Civil and Environmental Engineering, University of Iowa, Iowa City, IA, 52242, USA
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48
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Tangalos GE, Beard BL, Johnson CM, Alpers CN, Shelobolina ES, Xu H, Konishi H, Roden EE. Microbial production of isotopically light iron(II) in a modern chemically precipitated sediment and implications for isotopic variations in ancient rocks. GEOBIOLOGY 2010; 8:197-208. [PMID: 20374296 DOI: 10.1111/j.1472-4669.2010.00237.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The inventories and Fe isotope composition of aqueous Fe(II) and solid-phase Fe compounds were quantified in neutral-pH, chemically precipitated sediments downstream of the Iron Mountain acid mine drainage site in northern California, USA. The sediments contain high concentrations of amorphous Fe(III) oxyhydroxides [Fe(III)(am)] that allow dissimilatory iron reduction (DIR) to predominate over Fe-S interactions in Fe redox transformation, as indicated by the very low abundance of Cr(II)-extractable reduced inorganic sulfur compared with dilute HCl-extractable Fe. delta(56)Fe values for bulk HCl- and HF-extractable Fe were approximately 0. These near-zero bulk delta(56)Fe values, together with the very low abundance of dissolved Fe in the overlying water column, suggest that the pyrite Fe source had near-zero delta(56)Fe values, and that complete oxidation of Fe(II) took place prior to deposition of the Fe(III) oxide-rich sediment. Sediment core analyses and incubation experiments demonstrated the production of millimolar quantities of isotopically light (delta(56)Fe approximately -1.5 to -0.5 per thousand) aqueous Fe(II) coupled to partial reduction of Fe(III)(am) by DIR. Trends in the Fe isotope composition of solid-associated Fe(II) and residual Fe(III)(am) are consistent with experiments with synthetic Fe(III) oxides, and collectively suggest an equilibrium Fe isotope fractionation between aqueous Fe(II) and Fe(III)(am) of approximately -2 per thousand. These Fe(III) oxide-rich sediments provide a model for early diagenetic processes that are likely to have taken place in Archean and Paleoproterozoic marine sediments that served as precursors for banded iron formations. Our results suggest pathways whereby DIR could have led to the formation of large quantities of low-delta(56)Fe minerals during BIF genesis.
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Affiliation(s)
- G E Tangalos
- Department of Geoscience and NASA Astrobiology Institute, University of Wisconsin, Madison, WI, USA
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Jimenez-Lopez C, Romanek CS, Bazylinski DA. Magnetite as a prokaryotic biomarker: A review. ACTA ACUST UNITED AC 2010. [DOI: 10.1029/2009jg001152] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
| | - Christopher S. Romanek
- NASA Astrobiology Institute and Department of Earth and Environmental Sciences; University of Kentucky; Lexington Kentucky USA
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50
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Rustad JR, Dixon DA. Prediction of Iron-Isotope Fractionation Between Hematite (α-Fe2O3) and Ferric and Ferrous Iron in Aqueous Solution from Density Functional Theory. J Phys Chem A 2009; 113:12249-55. [DOI: 10.1021/jp9065373] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- James R. Rustad
- Department of Geology, University of California, Davis, One Shields Avenue, Davis, California 95616, and Department of Chemistry, University of Alabama, Tuscaloosa, Alabama 35487
| | - David A. Dixon
- Department of Geology, University of California, Davis, One Shields Avenue, Davis, California 95616, and Department of Chemistry, University of Alabama, Tuscaloosa, Alabama 35487
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