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Yin NH, Louvat P, Preud'homme H, Ronzani AL, Ash J, Berail S, Amouroux D. Precise measurement of Fe isotopes in marine and biological samples by pseudo-high-resolution multi-collector inductively coupled plasma mass spectrometry (MC-ICPMS). Anal Bioanal Chem 2024:10.1007/s00216-024-05343-4. [PMID: 38797772 DOI: 10.1007/s00216-024-05343-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Revised: 05/13/2024] [Accepted: 05/15/2024] [Indexed: 05/29/2024]
Abstract
This paper introduces an enhanced technique for analyzing iron isotopes in complex marine and biological samples. A dedicated iron purification method for biological marine matrices, utilizing three ion exchange columns, is validated. The MC-ICPMS in pseudo-high-resolution mode determines precise iron isotopic ratios, with sensitivity improved through the DSN-100 desolvating nebulizer system and Apex-IR. Only 2 µg of iron on DSN versus 1 µg on Apex is needed for six replicates (30-60 times improvement) while 10 to 20 µg is required for a single measurement on a wet system considering the resolution power (Rp) is maintained at 11,000-13,000. The Ni-doping method with a Fe/Ni ratio of 1 yields more accurate isotopic ratios than standard-sample bracketing alone. Measurement reproducibility of triplicate samples from marine biological experiments on MC-ICPMS is ± 0.03‰ (2SD) for δ56Fe and ± 0.07‰ for δ57Fe (2SD). This study introduces a novel iron purification process specifically designed for marine and biological samples, enhancing sensitivity and enabling more reliable measurements with smaller sample sizes and reduced uncertainties. It proposes iron isotopic compositions for biological reference materials, offering a valuable reference dataset in diverse scientific disciplines.
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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, Technopole Hélioparc, 2 Avenue du Président Pierre Angot, 64053, 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, Technopole Hélioparc, 2 Avenue du Président Pierre Angot, 64053, Pau, France
| | - Hugues Preud'homme
- 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, Technopole Hélioparc, 2 Avenue du Président Pierre Angot, 64053, Pau, France
| | - Anne-Laure Ronzani
- 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, Technopole Hélioparc, 2 Avenue du Président Pierre Angot, 64053, Pau, France
| | - James Ash
- Nu Instruments Ltd, UK, Unit 74, Clywedog Road South, Wrexham, LL13 9XS, UK
| | - Sylvain Berail
- 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, Technopole Hélioparc, 2 Avenue du Président Pierre Angot, 64053, Pau, France
- AIA (Advanced Isotopic Analyses) - Technopole Helioparc, 2 Av. du Président Pierre Angot, 64000, Pau, 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, Technopole Hélioparc, 2 Avenue du Président Pierre Angot, 64053, Pau, France
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2
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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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Hu S, Tao C, Liao S, Guan Y, Yin X, Zhu C, Liang J, Guo Z. Oxidative Dissolution of Sulfide Minerals Tends to Accumulate More Dissolved Heavy Metals in Deep Seawater Environments than in Shallow Seawater Environments. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:21438-21447. [PMID: 38051181 DOI: 10.1021/acs.est.3c07507] [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: 12/07/2023]
Abstract
Deep-sea mining magnifies the release of heavy metals into seawater through oxidative dissolution of seafloor massive sulfide (SMS). At present, there is little information about how the metals released into seawater might be affected by the mineral assemblages, seawater conditions, and solid percentages. Here, leaching experiments were carried out to examine the behavior of three sulfides from the Southwest Indian Ridge, under conditions that replicated deep and shallow seawater environments at three solid-liquid ratios. The results demonstrated that sphalerite dissolved rapidly, and the metals released in both experimental conditions were comparable, potentially reflecting galvanic interactions between the sulfide minerals. Large quantities of the released metals were removed from the solutions when hydrous ferric oxides formed, especially for shallow seawater conditions. A comparison of metal concentrations in the leachates with the baseline metal concentrations in natural seawater indicated that most of the released metals, when diluted with seawater, would not have widespread impacts on ecosystems. Based on the obtained unique oxidative dissolution properties of each SMS at variable solid-liquid ratios, targeted wastewater discharge treatments are proposed to minimize impacts from the dissolved metals. This study will support the development of robust guidelines for deep-sea mining activities.
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Affiliation(s)
- Siyi Hu
- Key Laboratory of Submarine Geosciences, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou 310012, China
- Guangxi Key Laboratory of Beibu Gulf Marine Resources, Environment and Sustainable Development, Fourth Institute of Oceanography, Ministry of Natural Resources, Beihai 536000, China
| | - Chunhui Tao
- Key Laboratory of Submarine Geosciences, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou 310012, China
- School of Oceanography, Shanghai Jiaotong University, Shanghai 200030, China
| | - Shili Liao
- Key Laboratory of Submarine Geosciences, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou 310012, China
| | - Yao Guan
- Guangxi Key Laboratory of Beibu Gulf Marine Resources, Environment and Sustainable Development, Fourth Institute of Oceanography, Ministry of Natural Resources, Beihai 536000, China
| | - Xuebo Yin
- Key Laboratory of Marine Geology and Environment, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China
| | - Chuanwei Zhu
- State Key Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
| | - Jin Liang
- Key Laboratory of Submarine Geosciences, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou 310012, China
| | - Zhikui Guo
- Key Laboratory of Submarine Geosciences, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou 310012, China
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4
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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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5
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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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González-Ramírez LA, Moreno A, Ng JD, García-Ruiz JM. Investigations on the Role of Iron (III) and Silica-Iron (III) for DNA Protection Against Highly Intense UV Radiation: Tracking the Connection of Prebiotic Chemistry to Biology. ASTROBIOLOGY 2023; 23:33-42. [PMID: 36257639 DOI: 10.1089/ast.2022.0004] [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
The mineral reaction pathways that yield organic compounds of increasing complexity would have required a means of protective screening against strong ultraviolet radiation for macromolecular assembly on early Earth. In this study, a bacterial chromosomal plasmid DNA was used as a model biomolecule that represents a complex polymeric nucleic acid containing genetic information. The plasmid DNA was exposed to UV radiation through a medium containing air, water, iron (Fe3+), or silica-iron rich aqueous solutions. Our results demonstrate that the plasmid DNA underwent covalent breakage in an aqueous solution when exposed to UV radiation but was shielded against damage due to the presence of iron and silica. It is demonstrated that a suspension of ca. 40 nm colloidal particles of silica gel embedded with Fe3+ ions adsorbed on silanol groups that formed nanoclusters of noncrystalline iron hydroxide is an extremely efficient shelter against intense UV radiation. The implications for our understanding of primitive Earth and Earth-like planets, moons, and asteroids are discussed. The stability of a chromosomal DNA molecule against UV radiation in the presence of iron and silica may provide support on how macromolecules endured early Earth environments and brought forth important implications on early molecular survival against UV radiation.
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Affiliation(s)
- Luis A González-Ramírez
- Laboratorio de Estudios Cristalográficos, Instituto Andaluz de Ciencias de la Tierra, CSIC-UGR, Armilla, Spain
| | - Abel Moreno
- Laboratorio de Estudios Cristalográficos, Instituto Andaluz de Ciencias de la Tierra, CSIC-UGR, Armilla, Spain
- Instituto de Química, Universidad Nacional Autónoma de México, Ciudad de México, México
| | - Joseph D Ng
- Department of Biological Sciences, University of Alabama in Huntsville, Huntsville, Alabama, USA
| | - Juan M García-Ruiz
- Laboratorio de Estudios Cristalográficos, Instituto Andaluz de Ciencias de la Tierra, CSIC-UGR, Armilla, Spain
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Burton ED, Karimian N, Hamilton JL, Frierdich AJ. Iron Isotopes in Acid Mine Drainage: Extreme and Divergent Fractionation between Solid (Schwertmannite, Jarosite, and Ferric Arsenate) and Aqueous Species. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:18060-18068. [PMID: 36442144 DOI: 10.1021/acs.est.2c05999] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Examination of stable Fe isotopes is a powerful tool to explore Fe cycling in a range of environments. However, the isotopic fractionation of Fe in acid mine drainage (AMD) has received little attention and is poorly understood. Here, we analyze Fe isotopes in waters and Fe(III)-rich solids along an AMD flow-path. Aqueous Fe spanned a concentration and δ56Fe range of ∼420 mg L-1 and + 0.04‰ at the AMD source to ∼100 mg L-1 and -0.81‰ at ∼450 m downstream. Aqueous As (up to ∼33 mg L-1) and SO42- (up to ∼2000 mg L-1), like aqueous Fe, decreased in concentration down the flow-path. X-ray absorption spectroscopy indicated that downstream attenuation in aqueous Fe, As, and SO42- was due to the precipitation of amorphous ferric arsenate (AFA), schwertmannite, and jarosite. The Fe(III) in these solids displayed extreme variability in δ56Fe, spanning +3.95‰ in AFA near the AMD source to -1.34‰ in schwertmannite at ∼450 m downstream. Similarly, the isotopic contrast between solid Fe(III) precipitates and aqueous Fe (Δ56Feppt-aq) dropped along the flow-path from about +4.1 to -1.1‰. The shift from positive to negative Δ56Feppt-aq reflects divergence between competing equilibrium versus kinetic fractionation processes.
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Affiliation(s)
- Edward D Burton
- Faculty of Science and Engineering, Southern Cross University, Lismore, NSW2480, Australia
| | - Niloofar Karimian
- School of Earth, Atmosphere & Environment, Monash University, Clayton, VIC3800, Australia
- CSIRO Mineral Resources, Clayton South, VIC3169, Australia
| | | | - Andrew J Frierdich
- School of Earth, Atmosphere & Environment, Monash University, Clayton, VIC3800, Australia
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Grigg ARC, ThomasArrigo LK, Schulz K, Rothwell KA, Kaegi R, Kretzschmar R. Ferrihydrite transformations in flooded paddy soils: rates, pathways, and product spatial distributions. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2022; 24:1867-1882. [PMID: 36131682 PMCID: PMC9580987 DOI: 10.1039/d2em00290f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Accepted: 09/15/2022] [Indexed: 06/15/2023]
Abstract
Complex interactions between redox-driven element cycles in soils influence iron mineral transformation processes. The rates and pathways of iron mineral transformation processes have been studied intensely in model systems such as mixed suspensions, but transformation in complex heterogeneous porous media is not well understood. Here, mesh bags containing 0.5 g of ferrihydrite were incubated in five water-saturated paddy soils with contrasting microbial iron-reduction potential for up to twelve weeks. Using X-ray diffraction analysis, we show near-complete transformation of the ferrihydrite to lepidocrocite and goethite within six weeks in the soil with the highest iron(II) release, and slower transformation with higher ratios of goethite to lepidocrocite in soils with lower iron(II) release. In the least reduced soil, no mineral transformations were observed. In soils where ferrihydrite transformation occurred, the transformation rate was one to three orders of magnitude slower than transformation in comparable mixed-suspension studies. To interpret the spatial distribution of ferrihydrite and its transformation products, we developed a novel application of confocal micro-Raman spectroscopy in which we identified and mapped minerals on selected cross sections of mesh bag contents. After two weeks of flooded incubation, ferrihydrite was still abundant in the core of some mesh bags, and as a rim at the mineral-soil interface. The reacted outer core contained unevenly mixed ferrihydrite, goethite and lepidocrocite on the micrometre scale. The slower rate of transformation and uneven distribution of product minerals highlight the influence of biogeochemically complex matrices and diffusion processes on the transformation of minerals, and the importance of studying iron mineral transformation in environmental media.
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Affiliation(s)
- Andrew R C Grigg
- Soil Chemistry Group, Institute of Biogeochemistry and Pollutant Dynamics, Department of Environmental Systems Science, ETH Zurich, Universitätstrasse 16, CHN, CH-8092 Zurich, Switzerland.
| | - Laurel K ThomasArrigo
- Soil Chemistry Group, Institute of Biogeochemistry and Pollutant Dynamics, Department of Environmental Systems Science, ETH Zurich, Universitätstrasse 16, CHN, CH-8092 Zurich, Switzerland.
| | - Katrin Schulz
- Soil Chemistry Group, Institute of Biogeochemistry and Pollutant Dynamics, Department of Environmental Systems Science, ETH Zurich, Universitätstrasse 16, CHN, CH-8092 Zurich, Switzerland.
| | - Katherine A Rothwell
- Soil Chemistry Group, Institute of Biogeochemistry and Pollutant Dynamics, Department of Environmental Systems Science, ETH Zurich, Universitätstrasse 16, CHN, CH-8092 Zurich, Switzerland.
| | - Ralf Kaegi
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Überlandstrasse 133, CH-8600 Dübendorf, Switzerland
| | - Ruben Kretzschmar
- Soil Chemistry Group, Institute of Biogeochemistry and Pollutant Dynamics, Department of Environmental Systems Science, ETH Zurich, Universitätstrasse 16, CHN, CH-8092 Zurich, Switzerland.
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9
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Pan W, Catalano JG, Giammar DE. Redox-Driven Recrystallization of PbO 2. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:7864-7872. [PMID: 35654758 DOI: 10.1021/acs.est.1c08767] [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
Lead(IV) oxide (PbO2) is one of the lead corrosion products that forms on the inner surface of lead pipes used for drinking water supply. It can maintain low dissolved Pb(II) concentrations when free chlorine is present. When free chlorine is depleted, PbO2 and soluble Pb(II) will co-occur in these systems. This study used a stable lead isotope (207Pb) as a tracer to examine the interaction between aqueous Pb(II) and solid PbO2 at conditions with no net change in dissolved Pb concentration. While the dissolved Pb(II) concentration remained unchanged, significant isotope exchange occurred that indicated that substantial amounts (24.3-35.0% based on the homogeneous recrystallization model) of the Pb atoms in the PbO2 solids had been exchanged with those in solution over 264 h. Neither α-PbO2 nor β-PbO2 displayed a change in mineralogy, particle size, or oxidation state after reaction with aqueous Pb(II). The combined isotope exchange and solid characterization results indicate that redox-driven recrystallization of PbO2 had occurred. Such redox-driven recrystallization is likely to occur in water that stagnates in lead pipes that contain PbO2, and this recrystallization may alter the reactivity of PbO2 with respect to its stability and susceptibility to reductive dissolution.
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Affiliation(s)
- Weiyi Pan
- Department of Energy, Environmental & Chemical Engineering, Washington University in St. Louis, Campus Box 1180, One Brookings Drive, St. Louis, Missouri 63130, United States
| | - Jeffrey G Catalano
- Department of Earth and Planetary Sciences, Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Daniel E Giammar
- Department of Energy, Environmental & Chemical Engineering, Washington University in St. Louis, Campus Box 1180, One Brookings Drive, St. Louis, Missouri 63130, United States
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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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11
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Liu J, Sheng A, Li X, Arai Y, Ding Y, Nie M, Yan M, Rosso KM. Understanding the Importance of Labile Fe(III) during Fe(II)-Catalyzed Transformation of Metastable Iron Oxyhydroxides. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:3801-3811. [PMID: 35188748 DOI: 10.1021/acs.est.1c08044] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Transformation of metastable Fe(III) oxyhydroxides is a prominent process in natural environments and can be significantly accelerated by the coexisting aqueous Fe(II) (Fe(II)aq). Recent evidence points to the solution mass transfer of labile Fe(III) (Fe(III)labile) as the primary intermediate species of general importance. However, a mechanistic aspect that remains unclear is the dependence of phase outcomes on the identity of the metastable Fe(III) oxyhydroxide precursor. Here, we compared the coupled evolution of Fe(II) species, solid phases, and Fe(III)labile throughout the Fe(II)-catalyzed transformation of lepidocrocite (Lp) versus ferrihydrite (Fh) at equal Fe(III) mass loadings with 0.2-1.0 mM Fe(II)aq at pH = 7.0. Similar to Fh, the conversion of Lp to product phases occurs by a dissolution-reprecipitation mechanism mediated by Fe(III)labile that seeds the nucleation of products. Though for Fh we observed a transformation to goethite (Gt), accompanied by the transient emergence and decline of Lp, for initial Lp we observed magnetite (Mt) as the main product. A linear correlation between the formation rate of Mt and the effective supersaturation in terms of Fe(III)labile concentration shows that Fe(II)-induced transformation of Lp into Mt is governed by the classical nucleation theory. When Lp is replaced by equimolar Gt, Mt formation is suppressed by opening a lower barrier pathway to Gt by heterogeneous nucleation and growth on the added Gt seeds. The collective findings add to the mechanistic understanding of factors governing phase selections that impact iron bioavailability, system redox potential, and the fate and transport of coupled elements.
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Affiliation(s)
- Juan Liu
- The Key Laboratory of Water and Sediment Sciences, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Anxu Sheng
- The Key Laboratory of Water and Sediment Sciences, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Xiaoxu Li
- The Key Laboratory of Water and Sediment Sciences, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Yuji Arai
- Department of Natural Resources and Environmental Sciences, University of Illinois at Urbana-Champaign, 1102 South Goodwin Avenue, Urbana, Illinois 61801, United States
| | - Yuefei Ding
- The Key Laboratory of Water and Sediment Sciences, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Mingjun Nie
- The Key Laboratory of Water and Sediment Sciences, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Mingquan Yan
- The Key Laboratory of Water and Sediment Sciences, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Kevin M Rosso
- Pacific Northwest National Laboratory, Richland, Washington 99354, United States
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12
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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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13
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Iron Isotopes Reveal a Benthic Iron Shuttle in the Palaeoproterozoic Zaonega Formation: Basinal Restriction, Euxinia, and the Effect on Global Palaeoredox Proxies. MINERALS 2021. [DOI: 10.3390/min11040368] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The Zaonega Formation in northwest Russia (~2.0 billion years old) is amongst the most complete successions that record the middle of the Palaeoproterozoic era. As such, geochemical data from the formation have played a central role in framing the debate over redox dynamics in the aftermath of the Great Oxidation Event (GOE). However, uncertainty over local redox conditions and the degree of hydrographic restriction in the formation has led to contradictory interpretations regarding global oxygen (O2) fugacity. Here, we provide new iron (Fe) isotope data together with major and trace element concentrations to constrain the local physiochemical conditions. The Zaonega Formation sediments show authigenic Fe accumulation (Fe/Al ≫ 1 wt.%/wt.%) and δ56Fe ranging from −0.58‰ to +0.60‰. Many of the data fall on a negative Fe/Al versus δ56Fe trend, diagnostic of a benthic Fe shuttle, which implies that Zaonega Formation rocks formed in a redox-stratified and semi-restricted basin. However, basin restriction did not coincide with diminished trace metal enrichment, likely due to episodes of deep-water exchange with metal-rich oxygenated seawater, as evidenced by simultaneous authigenic Fe(III) precipitation. If so, the Onega Basin maintained a connection that allowed its sediments to record signals of global ocean chemistry despite significant basinal effects.
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14
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Abstract
Dissolution of marine sediment is a key source of dissolved iron (Fe) that regulates the ocean carbon cycle. Currently, our prevailing understanding, encapsulated in ocean models, focuses on low-oxygen reductive supply mechanisms and neglects the emerging evidence from iron isotopes in seawater and sediment porewaters for additional nonreductive dissolution processes. Here, we combine measurements of Fe colloids and dissolved δ56Fe in shallow porewaters spanning the full depth of the South Atlantic Ocean to demonstrate that it is lithogenic colloid production that fuels sedimentary iron supply away from low-oxygen systems. Iron colloids are ubiquitous in these oxic ocean sediment porewaters and account for the lithogenic isotope signature of dissolved Fe (δ56Fe = +0.07 ± 0.07‰) within and between ocean basins. Isotope model experiments demonstrate that only lithogenic weathering in both oxic and nitrogenous zones, rather than precipitation or ligand complexation of reduced Fe species, can account for the production of these porewater Fe colloids. The broader covariance between colloidal Fe and organic carbon (OC) abundance suggests that sorption of OC may control the nanoscale stability of Fe minerals by inhibiting the loss of Fe(oxyhydr)oxides to more crystalline minerals in the sediment. Oxic ocean sediments can therefore generate a large exchangeable reservoir of organo-mineral Fe colloids at the sediment water interface (a "rusty source") that dominates the benthic supply of dissolved Fe to the ocean interior, alongside reductive supply pathways from shallower continental margins.
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15
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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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16
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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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17
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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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18
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Yang Y, Deng Y, Xie X, Gan Y, Li J. Iron isotope evidence for arsenic mobilization in shallow multi-level alluvial aquifers of Jianghan Plain, central China. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2020; 206:111120. [PMID: 32861962 DOI: 10.1016/j.ecoenv.2020.111120] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 07/28/2020] [Accepted: 07/31/2020] [Indexed: 06/11/2023]
Abstract
Intake of groundwater with arsenic (As) concentrations exceeding the World Health Organization standard of 10 μg L-1 adversely impacts over 100 million people worldwide. Geogenic As contaminated groundwater within central Yangtze River Basin has recently been reported, but the variations within different depths of aquifers are not commonly observed and the processes controlling As variations have yet to be resolved. Here we report the significant As variations within two different depths (10 m and 25 m) of shallow multi-level alluvial aquifers at Jianghan Plain, a floodplain in the central Yangtze River Basin, which is also a recently discovered geogenic As affected area with cases of waterborne arsenicosis. The multi-year monitoring of aquifer chemistry results show that the As concentrations increase with the Fe(II) concentrations when As contents are relatively lower (<200 μg L-1) in upper phreatic aquitard (at 10 m depth), while decrease with Fe(II) concentrations when As contents are much greater in lower confined aquifer (at 25 m depth), and the highest is up to 1070 μg L-1. Iron isotope analysis were conducive to characterize Fe cycling in the aquifers and thus illustrate geochemical processes controlling As mobilization of shallow groundwaters. Results showed that groundwater is generally enriched in isotopically light Fe with δ56Fe values between - 1.60‰ and + 0.06‰ (median - 0.55‰). In the upper phreatic aquitard, microbial reductive dissolution of As-associated Fe(III) oxides, hydroxides and oxyhydroxides is the major process controlling As concentrations lower than 200 μg L-1. The reduction process could lead to the increasing As concentrations with the gradually increasing δ56Fe values, and a positive correlation between Fe and δ56Fe, and between dissolved As and δ56Fe values is observed, respectively. In strongly reducing conditions as the lower confined aquifer, jointly microbial reduction of sulfate promotes the As mobilization through HS- abiotic reduction of Fe(III) minerals, resulting in As concentrations greater than 200 μg L-1. These findings could provide new insights for differentiating the major factors controlling As mobilization at different depths of aquifers, and provide better water managements for similar geogenic As-affected shallow alluvial aquifers.
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Affiliation(s)
- Yijun Yang
- School of Environmental Studies, China University of Geosciences, Wuhan, 430074, PR China
| | - Yamin Deng
- School of Environmental Studies, China University of Geosciences, Wuhan, 430074, PR China.
| | - Xianjun Xie
- School of Environmental Studies, China University of Geosciences, Wuhan, 430074, PR China
| | - Yiqun Gan
- School of Environmental Studies, China University of Geosciences, Wuhan, 430074, PR China
| | - Junxia Li
- School of Environmental Studies, China University of Geosciences, Wuhan, 430074, PR China
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19
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Liu Y, Tian Y, Zhang R, Guo H, Zhao W, Huang J. Corrosion behavior and mechanism of ductile iron with different degrees of deterioration of cement mortar lining in reclaimed water pipelines. RSC Adv 2020; 10:39627-39639. [PMID: 35515357 PMCID: PMC9057434 DOI: 10.1039/d0ra08042j] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2020] [Accepted: 10/12/2020] [Indexed: 11/21/2022] Open
Abstract
The influence of the degradation degree of cement mortar lining on the corrosion of the ductile iron pipe in reclaimed water.
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Affiliation(s)
- Yunhui Liu
- School of Environmental Science and Engineering
- Tianjin University
- Tianjin 300350
- China
| | - Yimei Tian
- School of Environmental Science and Engineering
- Tianjin University
- Tianjin 300350
- China
| | - Rufang Zhang
- School of Environmental Science and Engineering
- Tianjin University
- Tianjin 300350
- China
| | - Hao Guo
- The Institute of Seawater Desalination and Multipurpose Utilization
- MNR (Tianjin)
- Tianjin 300192
- China
| | - Weigao Zhao
- School of Environmental Science and Engineering
- Tianjin University
- Tianjin 300350
- China
| | - Jianjun Huang
- School of Environmental Science and Engineering
- Tianjin University
- Tianjin 300350
- China
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20
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Subglacial meltwater supported aerobic marine habitats during Snowball Earth. Proc Natl Acad Sci U S A 2019; 116:25478-25483. [PMID: 31792178 DOI: 10.1073/pnas.1909165116] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The Earth's most severe ice ages interrupted a crucial interval in eukaryotic evolution with widespread ice coverage during the Cryogenian Period (720 to 635 Ma). Aerobic eukaryotes must have survived the "Snowball Earth" glaciations, requiring the persistence of oxygenated marine habitats, yet evidence for these environments is lacking. We examine iron formations within globally distributed Cryogenian glacial successions to reconstruct the redox state of the synglacial oceans. Iron isotope ratios and cerium anomalies from a range of glaciomarine environments reveal pervasive anoxia in the ice-covered oceans but increasing oxidation with proximity to the ice shelf grounding line. We propose that the outwash of subglacial meltwater supplied oxygen to the synglacial oceans, creating glaciomarine oxygen oases. The confluence of oxygen-rich meltwater and iron-rich seawater may have provided sufficient energy to sustain chemosynthetic communities. These processes could have supplied the requisite oxygen and organic carbon source for the survival of early animals and other eukaryotic heterotrophs through these extreme glaciations.
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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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ThomasArrigo LK, Mikutta C, Byrne J, Kappler A, Kretzschmar R. Iron(II)-Catalyzed Iron Atom Exchange and Mineralogical Changes in Iron-rich Organic Freshwater Flocs: An Iron Isotope Tracer Study. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:6897-6907. [PMID: 28590131 DOI: 10.1021/acs.est.7b01495] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
In freshwater wetlands, organic flocs are often found enriched in trace metal(loid)s associated with poorly crystalline Fe(III)-(oxyhydr)oxides. Under reducing conditions, flocs may become exposed to aqueous Fe(II), triggering Fe(II)-catalyzed mineral transformations and trace metal(loid) release. In this study, pure ferrihydrite, a synthetic ferrihydrite-polygalacturonic acid coprecipitate (16.7 wt % C), and As- (1280 and 1230 mg/kg) and organic matter (OM)-rich (18.1 and 21.8 wt % C) freshwater flocs dominated by ferrihydrite and nanocrystalline lepidocrocite were reacted with an isotopically enriched 57Fe(II) solution (0.1 or 1.0 mM Fe(II)) at pH 5.5 and 7. Using a combination of wet chemistry, Fe isotope analysis, X-ray absorption spectroscopy (XAS), 57Fe Mössbauer spectroscopy and X-ray diffraction, we followed the Fe atom exchange kinetics and secondary mineral formation over 1 week. When reacted with Fe(II) at pH 7, pure ferrihydrite exhibited rapid Fe atom exchange at both Fe(II) concentrations, reaching 76 and 89% atom exchange in experiments with 0.1 and 1 mM Fe(II), respectively. XAS data revealed that it transformed into goethite (21%) at the lower Fe(II) concentration and into lepidocrocite (73%) and goethite (27%) at the higher Fe(II) concentration. Despite smaller Fe mineral particles in the coprecipitate and flocs as compared to pure ferrihydrite (inferred from Mössbauer-derived blocking temperatures), these samples showed reduced Fe atom exchange (9-30% at pH 7) and inhibited secondary mineral formation. No release of As was recorded for Fe(II)-reacted flocs. Our findings indicate that carbohydrate-rich OM in flocs stabilizes poorly crystalline Fe minerals against Fe(II)-catalyzed transformation by surface-site blockage and/or organic Fe(II) complexation. This hinders the extent of Fe atom exchange at mineral surfaces and secondary mineral formation, which may consequently impair Fe(II)-activated trace metal(loid) release. Thus, under short-term Fe(III)-reducing conditions facilitating the fast attainment of solid-solution equilibria (e.g., in stagnant waters), Fe-rich freshwater flocs are expected to remain an effective sink for trace elements.
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Affiliation(s)
- Laurel K ThomasArrigo
- Soil Chemistry Group, Institute of Biogeochemistry and Pollutant Dynamics, Department of Environmental Systems Science, CHN, ETH Zurich , Universitätstrasse 16, CH-8092 Zurich, Switzerland
| | - Christian Mikutta
- Soil Chemistry Group, Institute of Biogeochemistry and Pollutant Dynamics, Department of Environmental Systems Science, CHN, ETH Zurich , Universitätstrasse 16, CH-8092 Zurich, Switzerland
| | - James Byrne
- Geomicrobiology Group, Centre for Applied Geosciences (ZAG), University of Tübingen , Sigwartstrasse 10, D-72076, Tübingen, Germany
| | - Andreas Kappler
- Geomicrobiology Group, Centre for Applied Geosciences (ZAG), University of Tübingen , Sigwartstrasse 10, D-72076, Tübingen, Germany
| | - Ruben Kretzschmar
- Soil Chemistry Group, Institute of Biogeochemistry and Pollutant Dynamics, Department of Environmental Systems Science, CHN, ETH Zurich , Universitätstrasse 16, CH-8092 Zurich, Switzerland
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23
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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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24
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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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25
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Jones AM, Kinsela AS, Collins RN, Waite TD. The reduction of 4-chloronitrobenzene by Fe(II)-Fe(III) oxide systems - correlations with reduction potential and inhibition by silicate. JOURNAL OF HAZARDOUS MATERIALS 2016; 320:143-149. [PMID: 27529649 DOI: 10.1016/j.jhazmat.2016.08.031] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Revised: 08/09/2016] [Accepted: 08/10/2016] [Indexed: 06/06/2023]
Abstract
Recent studies have demonstrated that the rate at which Fe(II)-Fe(III) oxyhydroxide systems catalyze the reduction of reducible contaminants, such as 4-chloronitrobenzene, is well correlated to their thermodynamic reduction potential. Here we confirm this effect in the presence of Fe(III) oxyhydroxide phases not previously assessed, namely ferrihydrite and nano-goethite, as well as Fe(III) oxyhydroxide phases previously examined. In addition, silicate is found to decrease the extent of Fe(II) sorption to the Fe(III) oxyhydroxide surface, increasing the reduction potential of the Fe(II)-Fe(III) oxyhydroxide suspension and, accordingly, decreasing the rate of 4-chloronitrobenzene reduction. A linear relationship between the reduction potential of the Fe(II)-Fe(III) oxyhydroxide suspensions and the reduction rate of 4-chloronitrobenzene (normalized to surface area and concentration of sorbed Fe(II)) was obtained in the presence and absence of silicate. However, when ferrihydrite was doped with Si (through co-precipitation) the reduction of 4-chloronitrobenzene was much slower than predicted from its reduction potential. The results obtained have significant implications to the likely effectiveness of naturally occurring contaminant degradation processes involving Fe(II) and Fe(III) oxyhydroxides in groundwater environments containing high concentrations of silicate, or other species which compete with Fe(II) for sorption sites.
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Affiliation(s)
- Adele M Jones
- UNSW Water Research Centre, School of Civil and Environmental Engineering, UNSW Australia, Sydney, NSW, 2052, Australia.
| | - Andrew S Kinsela
- UNSW Water Research Centre, School of Civil and Environmental Engineering, UNSW Australia, Sydney, NSW, 2052, Australia
| | - Richard N Collins
- UNSW Water Research Centre, School of Civil and Environmental Engineering, UNSW Australia, Sydney, NSW, 2052, Australia
| | - T David Waite
- UNSW Water Research Centre, School of Civil and Environmental Engineering, UNSW Australia, Sydney, NSW, 2052, Australia.
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26
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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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27
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Frierdich AJ, Spicuzza MJ, Scherer MM. Oxygen Isotope Evidence for Mn(II)-Catalyzed Recrystallization of Manganite (γ-MnOOH). ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:6374-6380. [PMID: 27249316 DOI: 10.1021/acs.est.6b01463] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Manganese is biogeochemically cycled between aqueous Mn(II) and Mn(IV) oxides. Aqueous Mn(II) often coexists with Mn(IV) oxides, and redox reactions between the two (e.g., comproportionation) are well known to result in the formation of Mn(III) minerals. It is unknown, however, whether aqueous Mn(II) exchanges with structural Mn(III) in manganese oxides in the absence of any mineral transformation (similar to what has been reported for aqueous Fe(II) and some Fe(III) minerals). To probe whether atoms exchange between a Mn(III) oxide and water, we use a (17)O tracer to measure oxygen isotope exchange between structural oxygen in manganite (γ-MnOOH) and water. In the absence of aqueous Mn(II), about 18% of the oxygen atoms in manganite exchange with the aqueous phase, which is close to the estimated surface oxygen atoms (∼11%). In the presence of aqueous Mn(II), an additional 10% (for a total of 28%) of the oxygen atoms exchange with water, suggesting that some of the bulk manganite mineral (i.e., beyond surface) is exchanging with the fluid. Exchange of manganite oxygen with water occurs without any observable change in mineral phase and appears to be independent of the rapid Mn(II) sorption kinetics. These experiments suggest that Mn(II) catalyzes manganese oxide recrystallization and illustrate a new pathway by which these ubiquitous minerals interact with their surrounding fluid.
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Affiliation(s)
- Andrew J Frierdich
- School of Earth, Atmosphere & Environment, Monash University , Clayton, VIC 3800, Australia
| | - Michael J Spicuzza
- Department of Geoscience, University of Wisconsin , Madison, Wisconsin 53706, United States
| | - Michelle M Scherer
- Department of Civil and Environmental Engineering, University of Iowa , Iowa City, Iowa 52242, United States
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28
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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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29
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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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30
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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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31
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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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Distinct iron isotopic signatures and supply from marine sediment dissolution. Nat Commun 2014; 4:2143. [PMID: 23868399 PMCID: PMC3759054 DOI: 10.1038/ncomms3143] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2013] [Accepted: 06/11/2013] [Indexed: 11/16/2022] Open
Abstract
Oceanic iron inputs must be traced and quantified to learn how they affect primary productivity and climate. Chemical reduction of iron in continental margin sediments provides a substantial dissolved flux to the oceans, which is isotopically lighter than the crust, and so may be distinguished in seawater from other sources, such as wind-blown dust. However, heavy iron isotopes measured in seawater have recently led to the proposition of another source of dissolved iron from ‘non-reductive’ dissolution of continental margins. Here we present the first pore water iron isotope data from a passive-tectonic and semi-arid ocean margin (South Africa), which reveals a smaller and isotopically heavier flux of dissolved iron to seawater than active-tectonic and dysoxic continental margins. These data provide in situ evidence of non-reductive iron dissolution from a continental margin, and further show that geological and hydro-climatic factors may affect the amount and isotopic composition of iron entering the ocean. The dissolution of iron from sediments along ocean margins may stimulate photosynthesis and moderate global climate. This study shows how margin sediments supply iron in varying amounts between regions, and by distinct mechanisms, which may be due to geological characteristics and hydrological controls on land.
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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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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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Gorski CA, Handler RM, Beard BL, Pasakarnis T, Johnson CM, Scherer MM. Fe atom exchange between aqueous Fe2+ and magnetite. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2012; 46:12399-407. [PMID: 22577839 DOI: 10.1021/es204649a] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The reaction between magnetite and aqueous Fe(2+) has been extensively studied due to its role in contaminant reduction, trace-metal sequestration, and microbial respiration. Previous work has demonstrated that the reaction of Fe(2+) with magnetite (Fe(3)O(4)) results in the structural incorporation of Fe(2+) and an increase in the bulk Fe(2+) content of magnetite. It is unclear, however, whether significant Fe atom exchange occurs between magnetite and aqueous Fe(2+), as has been observed for other Fe oxides. Here, we measured the extent of Fe atom exchange between aqueous Fe(2+) and magnetite by reacting isotopically "normal" magnetite with (57)Fe-enriched aqueous Fe(2+). The extent of Fe atom exchange between magnetite and aqueous Fe(2+) was significant (54-71%), and went well beyond the amount of Fe atoms found at the near surface. Mössbauer spectroscopy of magnetite reacted with (56)Fe(2+) indicate that no preferential exchange of octahedral or tetrahedral sites occurred. Exchange experiments conducted with Co-ferrite (Co(2+)Fe(2)(3+)O(4)) showed little impact of Co substitution on the rate or extent of atom exchange. Bulk electron conduction, as previously invoked to explain Fe atom exchange in goethite, is a possible mechanism, but if it is occurring, conduction does not appear to be the rate-limiting step. The lack of significant impact of Co substitution on the kinetics of Fe atom exchange, and the relatively high diffusion coefficients reported for magnetite suggest that for magnetite, unlike goethite, Fe atom diffusion is a plausible mechanism to explain the rapid rates of Fe atom exchange in magnetite.
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Affiliation(s)
- Christopher A Gorski
- Environmental Chemistry, Swiss Federal Institute of Aquatic Science and Technology, Eawag, Ueberlandstrasse 133, 8600 Duebendorf, Switzerland
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Latta DE, Bachman JE, Scherer MM. Fe electron transfer and atom exchange in goethite: influence of Al-substitution and anion sorption. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2012; 46:10614-23. [PMID: 22963051 DOI: 10.1021/es302094a] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The reaction of Fe(II) with Fe(III) oxides and hydroxides is complex and includes sorption of Fe(II) to the oxide, electron transfer between sorbed Fe(II) and structural Fe(III), reductive dissolution coupled to Fe atom exchange, and, in some cases mineral phase transformation. Much of the work investigating electron transfer and atom exchange between aqueous Fe(II) and Fe(III) oxides has been done under relatively simple aqueous conditions in organic buffers to control pH and background electrolytes to control ionic strength. Here, we investigate whether electron transfer is influenced by cation substitution of Al(III) in goethite and the presence of anions such as phosphate, carbonate, silicate, and natural organic matter. Results from (57)Fe Mössbauer spectroscopy indicate that both Al-substitution (up to 9%) and the presence of common anions (PO(4)(3-), CO(3)(2-), SiO(4)(4-), and humic acid) does not inhibit electron transfer between aqueous Fe(II) and Fe(III) in goethite under the conditions we studied. In contrast, sorption of a long-chain phospholipid completely shuts down electron transfer. Using an enriched isotope tracer method, we found that Al-substitution in goethite (10%), does, however, significantly decrease the extent of atom exchange between Fe(II) and goethite (from 43 to 12%) over a month's time. Phosphate, somewhat surprisingly, appears to have little effect on the rate and extent of atom exchange between aqueous Fe(II) and goethite. Our results show that electron transfer between aqueous Fe(II) and solid Fe(III) in goethite can occur under wide range of geochemical conditions, but that the extent of redox-driven Fe atom exchange may be dependent on the presence of substituting cations such as Al.
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Affiliation(s)
- Drew E Latta
- Department of Civil and Environmental Engineering, The University of Iowa, Iowa City, Iowa 52242, United States.
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Basu A, Johnson TM. Determination of hexavalent chromium reduction using Cr stable isotopes: isotopic fractionation factors for permeable reactive barrier materials. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2012; 46:5353-5360. [PMID: 22424120 DOI: 10.1021/es204086y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Cr stable isotope measurements can provide improved estimates of the extent of Cr(VI) reduction to less toxic Cr(III). The relationship between observed (53)Cr/(52)Cr ratio shifts and the extent of reduction can be calibrated by determining the isotopic fractionation factor for relevant reactions. Permeable reactive barriers (PRB) made of Fe(0) and in situ redox manipulation (ISRM) zones effectively remediate Cr-contaminated aquifers. Here, we determine the isotopic fractionations for dominant reductants in reactive barriers and reduced sediments obtained from an ISRM zone at the US DOE's Hanford site. In all cases, significant isotopic fractionation was observed; fractionation (expressed as ε) was -3.91‰ for Fe(II)-doped goethite, -2.11‰ for FeS, -2.65‰ for green rust, -2.67‰ for FeCO(3), and -3.18‰ for ISRM zone sediments. These results provide a better calibration of the relationship between Cr isotope ratios and the extent of Cr(VI) reduction and aid in interpretation of Cr isotope data from systems with reactive barriers.
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Affiliation(s)
- Anirban Basu
- Department of Geology, University of Illinois at Urbana-Champaign, 208 Natural History Building, 1301 West Green Street, Urbana, Illinois 61801, United States.
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