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Hong Q, Cheng Y, Qu Y, Wei L, Liu Y, Gao J, Cai P, Chen T. Overlooked shelf sediment reductive sinks of dissolved rhenium and uranium in the modern ocean. Nat Commun 2024; 15:3966. [PMID: 38729935 DOI: 10.1038/s41467-024-48297-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2023] [Accepted: 04/24/2024] [Indexed: 05/12/2024] Open
Abstract
Rhenium (Re) and uranium (U) are essential proxies in reconstructing past oceanic oxygenation evolution. However, their removal in continental shelf sediments, hotspots of early diagenesis, were previously treated as quantitatively unimportant sinks in the ocean. Here we examine the sedimentary reductive removal of Re and U and their coupling with organic carbon decomposition, utilizing the 224Ra/228Th disequilibria within the East China Sea shelf. We identified positive correlations between their removal fluxes and the rates of sediment oxygen consumption or organic carbon decomposition. These correlations enable an evaluation of global shelf reductive sinks that are comparable to (for Re) or higher than (~4-fold for U) previously established suboxic/anoxic sinks. These findings suggest potential imbalances in the modern budgets of Re and U, or perhaps a substantial underestimation of their sources. Our study thus highlights shelf sedimentary reductive removal as critical yet overlooked sinks for Re and U in the modern ocean.
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Affiliation(s)
- Qingquan Hong
- State Key Laboratory for Mineral Deposits Research, School of Earth Sciences and Engineering and Frontiers Science Center for Critical Earth Material Cycling, Nanjing University, Nanjing, 210023, China
| | - Yilin Cheng
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, 361005, China
- College of Ocean and Earth Sciences, Xiamen University, Xiamen, 361005, China
| | - Yang Qu
- State Key Laboratory for Mineral Deposits Research, School of Earth Sciences and Engineering and Frontiers Science Center for Critical Earth Material Cycling, Nanjing University, Nanjing, 210023, China
| | - Lin Wei
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, 361005, China
- College of Ocean and Earth Sciences, Xiamen University, Xiamen, 361005, China
| | - Yumeng Liu
- State Key Laboratory for Mineral Deposits Research, School of Earth Sciences and Engineering and Frontiers Science Center for Critical Earth Material Cycling, Nanjing University, Nanjing, 210023, China
| | - Jianfeng Gao
- State Key Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China
| | - Pinghe Cai
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, 361005, China
- College of Ocean and Earth Sciences, Xiamen University, Xiamen, 361005, China
| | - Tianyu Chen
- State Key Laboratory for Mineral Deposits Research, School of Earth Sciences and Engineering and Frontiers Science Center for Critical Earth Material Cycling, Nanjing University, Nanjing, 210023, China.
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2
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Spielman-Sun E, Boye K, Dwivedi D, Engel M, Thompson A, Kumar N, Noël V. A Critical Look at Colloid Generation, Stability, and Transport in Redox-Dynamic Environments: Challenges and Perspectives. ACS EARTH & SPACE CHEMISTRY 2024; 8:630-653. [PMID: 38654896 PMCID: PMC11033945 DOI: 10.1021/acsearthspacechem.3c00255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/02/2023] [Revised: 01/20/2024] [Accepted: 02/07/2024] [Indexed: 04/26/2024]
Abstract
Colloid generation, stability, and transport are important processes that can significantly influence the fate and transport of nutrients and contaminants in environmental systems. Here, we critically review the existing literature on colloids in redox-dynamic environments and summarize the current state of knowledge regarding the mechanisms of colloid generation and the chemical controls over colloidal behavior in such environments. We also identify critical gaps, such as the lack of universally accepted cross-discipline definition and modeling infrastructure that hamper an in-depth understanding of colloid generation, behavior, and transport potential. We propose to go beyond a size-based operational definition of colloids and consider the functional differences between colloids and dissolved species. We argue that to predict colloidal transport in redox-dynamic environments, more empirical data are needed to parametrize and validate models. We propose that colloids are critical components of element budgets in redox-dynamic systems and must urgently be considered in field as well as lab experiments and reactive transport models. We intend to bring further clarity and openness in reporting colloidal measurements and fate to improve consistency. Additionally, we suggest a methodological toolbox for examining impacts of redox dynamics on colloids in field and lab experiments.
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Affiliation(s)
- Eleanor Spielman-Sun
- Environmental
Geochemistry Group at SLAC, Stanford Synchrotron Radiation Lightsource
(SSRL), SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Kristin Boye
- Environmental
Geochemistry Group at SLAC, Stanford Synchrotron Radiation Lightsource
(SSRL), SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Dipankar Dwivedi
- Earth
and Environmental Sciences Area, Lawrence
Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Maya Engel
- Department
of Soil and Water Sciences, Faculty of Agriculture, Food, and Environment, The Hebrew University of Jerusalem, Rehovot 7610001, Israel
| | - Aaron Thompson
- Department
of Crop and Soil Sciences, University of
Georgia, Athens, Georgia 30602, United States
| | - Naresh Kumar
- Soil
Chemistry, Wageningen University and Research, Wageningen 6708 PB, The Netherlands
| | - Vincent Noël
- Environmental
Geochemistry Group at SLAC, Stanford Synchrotron Radiation Lightsource
(SSRL), SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
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3
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Coutelot F, Wheeler J, Merino N, Kaplan DI, Owings S, Taillefert M, Zavarin M, Kersting AB, Powell BA. Temporal evolution of Pu and Cs sediment contamination in a seasonally stratified pond. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 857:159320. [PMID: 36220478 DOI: 10.1016/j.scitotenv.2022.159320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Revised: 09/30/2022] [Accepted: 10/05/2022] [Indexed: 06/16/2023]
Abstract
There remains a lack of knowledge regarding ecosystem transfer, transport processes, and mechanisms, which influence the long-term mobility of Pu-239 and Cs-137 in natural environments. Monitoring the distribution and migration of trace radioisotopes as ecosystem tracers has the potential to provide insight into the underlying mechanisms of geochemical cycles. This study investigated the distribution of anthropogenic radionuclides Pu-239 and Cs-137 along with total organic carbon, iron, and trace element in contaminated sediments of Pond B at the Savannah River Site (SRS). Pond B received reactor cooling water from 1961 to 1964, and trace amounts of Pu-239 and Cs-137 during operations. Our study collected sediment cores to determine concentrations of Pu-239, Cs-137, and major and minor elements in solid phase, pore water and an electrochemical method was used on wet cores to determine dissolved elemental concentrations. More than 50 years after deposition, Pu-239 and Cs-137 in sediments are primarily located in the upper 5 cm in area where deposition of particulate-bound contaminants was prevalent and located between 5 and 10 cm in areas of high sedimentation, showing a limited migration of Pu-239 and Cs-137. A Factor analysis demonstrated different sediment facies across the pond resulting in a range of geochemical processes controlling accumulation of Pu and Cs. Highest concentrations appear to be controlled by particulate input from the influent canal, dominated by clay, silt, and sand minerals bearing Fe. Elevated Pu-239 in the sediments were observed in areas with high organic matter and higher deposition rate relative to the Pond B system near the outlet indicating strong association of Pu with OM and particulates. Therefore, organic matter cycling likely plays a role in Pu redistribution between sediment and overlying pond water, and deposition in organic rich sediments accumulating near the outlet. Though Pu appears to have been distributed throughout the pond, Cs-137 concentrations remained the highest near the influent canal.
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Affiliation(s)
- Fanny Coutelot
- Department of Environmental Engineering and Earth Sciences, Clemson University, Anderson, SC, United States; Center for Nuclear Environmental Engineering and Science and Radioactive Waste Management, Clemson University, Anderson, SC 29625, United States.
| | - Jessica Wheeler
- Department of Environmental Engineering and Earth Sciences, Clemson University, Anderson, SC, United States; Center for Nuclear Environmental Engineering and Science and Radioactive Waste Management, Clemson University, Anderson, SC 29625, United States
| | - Nancy Merino
- The Glenn T. Seaborg Institute, Lawrence Livermore National Laboratory, Livermore, CA, United States
| | - Daniel I Kaplan
- Savannah River National Laboratory, Aiken, SC, United States
| | - Shannon Owings
- Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, United States
| | - Martial Taillefert
- Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, United States
| | - Mavrik Zavarin
- The Glenn T. Seaborg Institute, Lawrence Livermore National Laboratory, Livermore, CA, United States
| | - Annie B Kersting
- The Glenn T. Seaborg Institute, Lawrence Livermore National Laboratory, Livermore, CA, United States
| | - Brian A Powell
- Department of Environmental Engineering and Earth Sciences, Clemson University, Anderson, SC, United States; Center for Nuclear Environmental Engineering and Science and Radioactive Waste Management, Clemson University, Anderson, SC 29625, United States.
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4
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Lueder U, Maisch M, Jørgensen BB, Druschel G, Schmidt C, Kappler A. Growth of microaerophilic Fe(II)-oxidizing bacteria using Fe(II) produced by Fe(III) photoreduction. GEOBIOLOGY 2022; 20:421-434. [PMID: 35014744 DOI: 10.1111/gbi.12485] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 11/10/2021] [Accepted: 12/31/2021] [Indexed: 06/14/2023]
Abstract
Iron(II) (Fe(II)) can be formed by abiotic Fe(III) photoreduction, particularly when Fe(III) is organically complexed. Light-influenced environments often overlap or even coincide with oxic or microoxic geochemical conditions, for example, in sediments. So far, it is unknown whether microaerophilic Fe(II)-oxidizing bacteria are able to use the Fe(II) produced by Fe(III) photoreduction as electron donor. Here, we present an adaption of the established agar-stabilized gradient tube approach in comparison with liquid cultures for the cultivation of microaerophilic Fe(II)-oxidizing microorganisms by using a ferrihydrite-citrate mixture undergoing Fe(III) photoreduction as Fe(II) source. We quantified oxygen and Fe(II) gradients with amperometric and voltammetric microelectrodes and evaluated microbial growth by qPCR of 16S rRNA genes. We showed that gradients of dissolved Fe(II) (maximum Fe(II) concentration of 1.25 mM) formed in the gradient tubes when incubated in blue or UV light (400-530 nm or 350-400 nm). Various microaerophilic Fe(II)-oxidizing bacteria (Curvibacter sp. and Gallionella sp.) grew by oxidizing Fe(II) that was produced in situ by Fe(III) photoreduction. Best growth for these species, based on highest gene copy numbers, was observed in incubations using UV light in both liquid culture and gradient tubes containing 8 mM ferrihydrite-citrate mixtures (1:1), due to continuous light-induced Fe(II) formation. Microaerophilic Fe(II)-oxidizing bacteria contributed up to 40% to the overall Fe(II) oxidation within 24 h of incubation in UV light. Our results highlight the potential importance of Fe(III) photoreduction as a source of Fe(II) for Fe(II)-oxidizing bacteria by providing Fe(II) in illuminated environments, even under microoxic conditions.
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Affiliation(s)
- Ulf Lueder
- Geomicrobiology Group, Center for Applied Geoscience (ZAG), University of Tuebingen, Tuebingen, Germany
| | - Markus Maisch
- Geomicrobiology Group, Center for Applied Geoscience (ZAG), University of Tuebingen, Tuebingen, Germany
| | - Bo Barker Jørgensen
- Section for Microbiology, Department of Biology, Aarhus University, Aarhus, Denmark
| | - Gregory Druschel
- Department of Earth Sciences, Indiana University-Purdue University, Indianapolis, Indiana, USA
| | - Caroline Schmidt
- Geomicrobiology Group, Center for Applied Geoscience (ZAG), University of Tuebingen, Tuebingen, Germany
| | - Andreas Kappler
- Geomicrobiology Group, Center for Applied Geoscience (ZAG), University of Tuebingen, Tuebingen, Germany
- Section for Microbiology, Department of Biology, Aarhus University, Aarhus, Denmark
- Cluster of Excellence: EXC 2124: Controlling Microbes to Fight Infection, Tübingen, Germany
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5
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Hudson JM, Michaud AB, Emerson D, Chin YP. Spatial distribution and biogeochemistry of redox active species in arctic sedimentary porewaters and seeps. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2022; 24:426-438. [PMID: 35170586 DOI: 10.1039/d1em00505g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Redox active species in Arctic lacustrine sediments play an important, regulatory role in the carbon cycle, yet there is little information on their spatial distribution, abundance, and oxidation states. Here, we use voltammetric microelectrodes to quantify the in situ concentrations of redox-active species at high vertical resolution (mm to cm) in the benthic porewaters of an oligotrophic Arctic lake (Toolik Lake, AK, USA). Mn(II), Fe(II), O2, and Fe(III)-organic complexes were detected as the major redox-active species in these porewaters, indicating both Fe(II) oxidation and reductive dissolution of Fe(III) and Mn(IV) minerals. We observed significant spatial heterogeneity in their abundance and distribution as a function of both location within the lake and depth. Microbiological analyses and solid phase Fe(III) measurements were performed in one of the Toolik Lake cores to determine the relationship between biogeochemical redox gradients and microbial communities. Our data reveal iron cycling involving both oxidizing (FeOB) and reducing (FeRB) bacteria. Additionally, we profiled a large microbial iron mat in a tundra seep adjacent to an Arctic stream (Oksrukuyik Creek) where we observed Fe(II) and soluble Fe(III) in a highly reducing environment. The variable distribution of redox-active substances at all the sites yields insights into the nature and distribution of the important terminal electron acceptors in both lacustrine and tundra environments capable of exerting significant influences on the carbon cycle.
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Affiliation(s)
- Jeffrey M Hudson
- Department of Civil and Environmental Engineering, University of Delaware, Newark, Delaware 19716, USA.
| | | | - David Emerson
- Bigelow Laboratory for Ocean Sciences, East Boothbay, Maine, 04544, USA
| | - Yu-Ping Chin
- Department of Civil and Environmental Engineering, University of Delaware, Newark, Delaware 19716, USA.
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6
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Bailon MX, Park M, Solis KL, Na Y, Chaudhary DK, Kim S, Hong Y. Reduction in mercury bioavailability to Asian clams (Corbicula fluminea) and changes in bacterial communities in sediments with activated carbon amendment. CHEMOSPHERE 2022; 291:132700. [PMID: 34710454 DOI: 10.1016/j.chemosphere.2021.132700] [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: 05/21/2021] [Revised: 08/23/2021] [Accepted: 10/24/2021] [Indexed: 06/13/2023]
Abstract
Activated carbon (AC) amendment is considered as one of the alternatives for managing and remediating mercury (Hg) contaminated sediments because of its high sorptive capacity and potential to immobilize the contaminant. For this study, the underlying mechanisms that control the reduction of Hg bioavailability in AC-amended estuarine sediments were investigated in box microcosm set-ups with 28-day Asian clam bioassay experiments. The application of diffusive gradients in thin film technique (DGT) revealed that the total mercury and methylmercury levels in sediment pore water decreased by 60%-75% in 1%-3% AC-amended sediments. This decrease subsequently led to a linear reduction in the Hg body burden in Asian clams, even at 1% sorbent mixing. These observations implied that AC amendment reduced the net flux of Hg into the pore water and overlying water, resulting in reduced Hg bioaccumulation in benthic organisms. The addition of AC to sediment also led to reduced dissolved organic carbon and several biogeochemical indicators (HS-, Mn, and Fe) in the pore water. Furthermore, the 16 S rRNA gene amplicon sequencing analysis revealed noticeable alterations in the microbial communities after AC amendment. The predominant phylum was Firmicutes in control sediment, Bacteroidetes in 1% AC-amended sediment, and Proteobacteria in both 2% and 3% AC-amended sediment samples. The genera-level analysis showed that the relative abundance of the Hg-methylators decreased as the level of AC amendment increased. These observations suggested that AC amendment decreased Hg bioavailability not only by physicochemical sorption but also by changing geochemical species and shifting the microbial community composition.
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Affiliation(s)
- Mark Xavier Bailon
- Department of Environmental Engineering, Korea University Sejong Campus, 2511 Sejong-ro, Sejong City, 30019, South Korea; Department of Science and Technology, Philippine Science High School - Central Luzon Campus, Lily Hill, Clark Freeport Zone, Mabalacat City, Pampanga, 2010, Philippines
| | - Minoh Park
- Department of Environmental Engineering, Korea University Sejong Campus, 2511 Sejong-ro, Sejong City, 30019, South Korea
| | - Kurt Louis Solis
- Department of Environmental Engineering, Korea University Sejong Campus, 2511 Sejong-ro, Sejong City, 30019, South Korea
| | - Yeong Na
- Department of Environmental Engineering, Korea University Sejong Campus, 2511 Sejong-ro, Sejong City, 30019, South Korea
| | - Dhiraj Kumar Chaudhary
- Department of Environmental Engineering, Korea University Sejong Campus, 2511 Sejong-ro, Sejong City, 30019, South Korea
| | - Sungpyo Kim
- Department of Environmental Engineering, Korea University Sejong Campus, 2511 Sejong-ro, Sejong City, 30019, South Korea
| | - Yongseok Hong
- Department of Environmental Engineering, Korea University Sejong Campus, 2511 Sejong-ro, Sejong City, 30019, South Korea.
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7
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Patin NV, Dietrich ZA, Stancil A, Quinan M, Beckler JS, Hall ER, Culter J, Smith CG, Taillefert M, Stewart FJ. Gulf of Mexico blue hole harbors high levels of novel microbial lineages. THE ISME JOURNAL 2021; 15:2206-2232. [PMID: 33612832 PMCID: PMC8319197 DOI: 10.1038/s41396-021-00917-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2020] [Revised: 01/14/2021] [Accepted: 01/27/2021] [Indexed: 01/31/2023]
Abstract
Exploration of oxygen-depleted marine environments has consistently revealed novel microbial taxa and metabolic capabilities that expand our understanding of microbial evolution and ecology. Marine blue holes are shallow karst formations characterized by low oxygen and high organic matter content. They are logistically challenging to sample, and thus our understanding of their biogeochemistry and microbial ecology is limited. We present a metagenomic and geochemical characterization of Amberjack Hole on the Florida continental shelf (Gulf of Mexico). Dissolved oxygen became depleted at the hole's rim (32 m water depth), remained low but detectable in an intermediate hypoxic zone (40-75 m), and then increased to a secondary peak before falling below detection in the bottom layer (80-110 m), concomitant with increases in nutrients, dissolved iron, and a series of sequentially more reduced sulfur species. Microbial communities in the bottom layer contained heretofore undocumented levels of the recently discovered phylum Woesearchaeota (up to 58% of the community), along with lineages in the bacterial Candidate Phyla Radiation (CPR). Thirty-one high-quality metagenome-assembled genomes (MAGs) showed extensive biochemical capabilities for sulfur and nitrogen cycling, as well as for resisting and respiring arsenic. One uncharacterized gene associated with a CPR lineage differentiated hypoxic from anoxic zone communities. Overall, microbial communities and geochemical profiles were stable across two sampling dates in the spring and fall of 2019. The blue hole habitat is a natural marine laboratory that provides opportunities for sampling taxa with under-characterized but potentially important roles in redox-stratified microbial processes.
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Affiliation(s)
- N V Patin
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA.
- Center for Microbial Dynamics and Infection, Georgia Institute of Technology, Atlanta, GA, USA.
- Ocean Chemistry and Ecosystems Division, Atlantic Oceanographic and Meteorological Laboratory, National Oceanic and Atmospheric Administration, Miami, FL, USA.
- Cooperative Institute for Marine and Atmospheric Studies, Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL, USA.
- Stationed at Southwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, La Jolla, CA, USA.
| | | | - A Stancil
- Harbor Branch Oceanographic Institute, Florida Atlantic University, Ft. Pierce, FL, USA
| | - M Quinan
- Harbor Branch Oceanographic Institute, Florida Atlantic University, Ft. Pierce, FL, USA
| | - J S Beckler
- Harbor Branch Oceanographic Institute, Florida Atlantic University, Ft. Pierce, FL, USA
| | - E R Hall
- Mote Marine Laboratory, Sarasota, FL, USA
| | - J Culter
- Mote Marine Laboratory, Sarasota, FL, USA
| | - C G Smith
- U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center, St. Petersburg, FL, USA
| | - M Taillefert
- School of Earth & Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - F J Stewart
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA
- Center for Microbial Dynamics and Infection, Georgia Institute of Technology, Atlanta, GA, USA
- Department of Microbiology & Immunology, Montana State University, Bozeman, MT, USA
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8
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Fu Y, Guo Z, Pan F, Cai Y, Wu J, Wang B. Distribution characteristics and release mechanisms of Pb in surface sediments in different aquatic environments. JOURNAL OF CONTAMINANT HYDROLOGY 2020; 235:103704. [PMID: 32896763 DOI: 10.1016/j.jconhyd.2020.103704] [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: 03/23/2020] [Revised: 07/03/2020] [Accepted: 08/24/2020] [Indexed: 06/11/2023]
Abstract
As a trace heavy metal, lead (Pb) has many anthropogenic applications but also produces many environmental pollution problems because of its high toxicity. In this study, we combined two in situ high-resolution sampling techniques - high-resolution dialysis (HR-Peeper) and diffusive gradients in thin films (DGT) - with the DGT-induced fluxes in sediment (DIFS) model to explore the mechanism of Pb release and resupply between sediments and pore water in the lower reaches and estuary of the Jiuxi River and the adjacent coast. An analysis of the chemical forms of Pb in the sediments showed that the content of the acid-extractable fraction (F1) was higher at the coastal site than at the other sampling sites, which indicates that Pb in the coastal sediments had greater activity and was more likely to cause Pb pollution. The apparent diffusion fluxes of Pb across the sediment-water interface (SWI) in the lower reaches, estuary and coastal zone are negative, and the absolute value of Pb flux in the estuary is several times higher than that in the other two stations, indicating a strong downward Pb diffusion trend, which may be due to water pollution caused by the nearby sewage outlet. As an insensitive element to redox, Pb did not exhibit an obvious correlation with Fe. In particular, the high Pb concentration and strong downward diffusion trend of the overlying water in the estuary caused the significant negative correlation between Pb and Fe. The calculated results of the DIFS model show that the reduced layer in the intertidal zone along the coast has the highest R value, the highest desorption rate (k-1) and the shortest response time (Tc), indicating that sediment particles in the coastal intertidal zone supply Pb to the pore water at the fastest rate; consequently, Pb pollution in the coastal zone is worthy of further attention.
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Affiliation(s)
- Yuyao Fu
- College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, PR China
| | - Zhanrong Guo
- College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, PR China.
| | - Feng Pan
- College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, PR China
| | - Yu Cai
- College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, PR China
| | - Jinye Wu
- College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, PR China
| | - Bo Wang
- College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, PR China
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9
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Abstract
Gold amalgam microelectrodes (GAMEs) have been characterized and successfully calibrated to measure >1.5 mM (30 mg L−1) sulfide in artificial wastewater (AWW) using cathodic stripping voltammetry (CSV). Microbial sulfide generation in two types of AWW was traced. Artificial wastewater type 1 (AWW1) held the potential for almost 50% conversion of sulfur compounds at a maximum rate of ~4.3 ± 0.5 µM h−1 while AWW 2 held a potential for 75–100% conversion at a rate of 165 µM h−1. In addition, the GAMEs were thoroughly examined during fabrication, maturation, and aging. An earlier described plating method was found to result in varying electrode surfaces due to excess mercury deposition and, therefore, deviating stripping signals. The limited shelf life of GAMEs has been proposed previously. This study shows the extent of electrode surface changes during amalgam formation and the wear and tear of application. As a result, suggestions to optimize fabrication and application are discussed to provide reliable measurements and proceed toward a future commercialization.
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10
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Guédron S, Audry S, Acha D, Bouchet S, Point D, Condom T, Heredia C, Campillo S, Baya PA, Groleau A, Amice E, Amouroux D. Diagenetic production, accumulation and sediment-water exchanges of methylmercury in contrasted sediment facies of Lake Titicaca (Bolivia). THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 723:138088. [PMID: 32392692 DOI: 10.1016/j.scitotenv.2020.138088] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Revised: 03/18/2020] [Accepted: 03/19/2020] [Indexed: 06/11/2023]
Abstract
Monomethylmercury (MMHg) concentrations in aquatic biota from Lake Titicaca are elevated although the mercury (Hg) contamination level of the lake is low. The contribution of sediments to the lake MMHg pool remained however unclear. In this work, seven cores representative of the contrasted sediments and aquatic ecotopes of Lake Titicaca were sliced and analyzed for Hg and redox-sensitive elements (Mn, Fe, N and S) speciation in pore-water (PW) and sediment to document early diagenetic processes responsible for MMHg production and accumulation in PW during organic matter (OM) oxidation. The highest MMHg concentrations (up to 12.2 ng L-1 and 90% of THg) were found in subsurface PWs of the carbonate-rich sediments which cover 75% of the small basin and 20% of the large one. In other sediment facies, the larger content of OM restricted MMHg production and accumulation in PW by sequestering Hg in the solid phase and potentially also by decreasing its bioavailability in the PW. Diagenetically reduced S and Fe played a dual role either favoring or restricting the availability of Hg for biomethylation. The calculation of theoretical diffusive fluxes suggests that Lake Titicaca bottom sediments are a net source of MMHg, accounting for more than one third of the daily MMHg accumulated in the water column of the Lago Menor. We suggest that in the context of rising anthropogenic pressure, the enhancement of eutrophication in high altitude Altiplano lakes may increase these MMHg effluxes into the water column and favor its accumulation in water and biota.
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Affiliation(s)
- S Guédron
- Univ. Grenoble Alpes, Univ. Savoie Mont Blanc, CNRS, IRD, IFSTTAR, ISTerre, 38000 Grenoble, France; Laboratorio de Hidroquímica, Instituto de Investigaciones Químicas, Universidad Mayor de San Andres, Campus Universitario de Cota Cota, casilla 3161, La Paz, Bolivia.
| | - S Audry
- Géosciences Environnement Toulouse, UMR5563, IRD UR 154, Université Paul Sabatier, 14 Avenue Edouard Belin, 31400 Toulouse, France
| | - D Acha
- Unidad de Calidad Ambiental (UCA), Instituto de Ecología, Universidad Mayor de San Andrés, Campus Universitario de Cota Cota, casilla 3161, La Paz, Bolivia
| | - S Bouchet
- 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
| | - D Point
- Géosciences Environnement Toulouse, UMR5563, IRD UR 154, Université Paul Sabatier, 14 Avenue Edouard Belin, 31400 Toulouse, France
| | - T Condom
- Univ. Grenoble Alpes, CNRS, IRD, Grenoble INP, Institut des Géosciences de l'Environnement (IGE), UMR 5001, F-38000 Grenoble, France
| | - C Heredia
- Univ. Grenoble Alpes, Univ. Savoie Mont Blanc, CNRS, IRD, IFSTTAR, ISTerre, 38000 Grenoble, France; Unidad de Calidad Ambiental (UCA), Instituto de Ecología, Universidad Mayor de San Andrés, Campus Universitario de Cota Cota, casilla 3161, La Paz, Bolivia
| | - S Campillo
- Univ. Grenoble Alpes, Univ. Savoie Mont Blanc, CNRS, IRD, IFSTTAR, ISTerre, 38000 Grenoble, France
| | - P A Baya
- Géosciences Environnement Toulouse, UMR5563, IRD UR 154, Université Paul Sabatier, 14 Avenue Edouard Belin, 31400 Toulouse, France
| | - A Groleau
- Institut de Physique du Globe de Paris (IPGP), 1, rue Jussieu, 75238 Paris Cedex 05, France
| | - E Amice
- LEMAR- Laboratoire des sciences de l'environnement marin, Institut Universitaire Européen de la Mer - Technopôle Brest-Iroise, Rue Dumont d'Urville, 29280 Plouzané, France
| | - D Amouroux
- Unidad de Calidad Ambiental (UCA), Instituto de Ecología, Universidad Mayor de San Andrés, Campus Universitario de Cota Cota, casilla 3161, La Paz, Bolivia; 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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11
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Lieb HC, Nguyen BD, Ramsayer ER, Mullaugh KM. A voltammetric investigation of the sulfidation of silver nanoparticles by zinc sulfide. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 720:137685. [PMID: 32325601 DOI: 10.1016/j.scitotenv.2020.137685] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 02/10/2020] [Accepted: 03/01/2020] [Indexed: 06/11/2023]
Abstract
Silver nanoparticles (Ag NPs) are among the most common forms of nanoparticles in consumer products, yet the environmental implications of their widespread use remain unclear due to uncertainties about their fate. Because sulfidation of Ag NPs results in the formation of a stable silver sulfide (Ag2S) product, it is likely an important removal mechanism of bioavailable silver in natural waters. In addition to sulfide, the complete conversion of Ag NPs to Ag2S will require dissolved oxygen or some other oxidant so dispersed metal sulfides may be an important pool of reactive sulfide for such reactions in oxygenated systems. The reaction of Ag NPs with zinc sulfide (ZnS) was investigated using a voltammetric method, anodic stripping voltammetry (ASV). ASV provided sensitive, in situ measurements of the release of zinc (Zn2+) cations resulting from the cation exchange reaction between Ag NPs and ZnS. The effects of Ag NP size and surface coatings on the initial rates of sulfidation by ZnS were examined. Sulfidation of smaller Ag NPs generally occurred faster and to a greater extent due to their larger relative surface areas. Sulfidation of Ag NPs capped by citrate and lipoic acid occurred more rapidly relative to polyvinylpyrrolidone (PVP) and branched polyethylene (BPEI). This study demonstrates the utility of voltammetry for such investigations and provides insights into important factors controlling Ag NP sulfidation such as availability of dissolved oxygen, Ag NP size and Ag NP surface coating. Furthermore, this work demonstrates the importance of cation exchange reactions between silver and metal sulfides, and how the environmental release of Ag NPs could alter the speciation of other metals of environmental significance.
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Affiliation(s)
- Heather C Lieb
- Department of Chemistry & Biochemistry, 66 George St., College of Charleston, Charleston, SC, USA
| | - Bach D Nguyen
- Department of Chemistry & Biochemistry, 66 George St., College of Charleston, Charleston, SC, USA
| | - Emily R Ramsayer
- Department of Chemistry & Biochemistry, 66 George St., College of Charleston, Charleston, SC, USA
| | - Katherine M Mullaugh
- Department of Chemistry & Biochemistry, 66 George St., College of Charleston, Charleston, SC, USA.
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12
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Hädrich A, Taillefert M, Akob DM, Cooper RE, Litzba U, Wagner FE, Nietzsche S, Ciobota V, Rösch P, Popp J, Küsel K. Microbial Fe(II) oxidation by Sideroxydans lithotrophicus ES-1 in the presence of Schlöppnerbrunnen fen-derived humic acids. FEMS Microbiol Ecol 2020; 95:5381554. [PMID: 30874727 DOI: 10.1093/femsec/fiz034] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Accepted: 03/14/2019] [Indexed: 11/14/2022] Open
Abstract
Controlled laboratory experiments were combined with field measurements to better understand the interactions between dissolved organic matter (DOM) and reduced iron in organic-rich peatlands. Addition of peat-derived humic acid extract (HA) to Sideroxydans lithotrophicus ES-1 liquid cultures led to higher cell numbers and up to 1.4 times higher Fe(II) oxidation rates compared to chemical controls. This effect was positively correlated with increasing HA concentrations. Similar Fe(III) (oxyhydr)oxide mineralogies were formed both abiotically and biotically irrespective of HA amendment, but minerals formed in the presence of ES-1 and HA were smaller. ES-1 growth with HA promoted aggregation of Fe(III) products in agarose-stabilized gradient tubes as shown by voltammetric profiling. In situ voltammetry in an acidic, iron-rich peatland revealed a gap between oxygen penetration and iron reduction that may reflect active Fe(II)-oxidizing microorganisms. The highest abundance of Fe(II) oxidizers Sideroxydans (4.9 × 107 gene copies gww-1) and Gallionella (1.5 × 107 gene copies gww-1) in the upper peat layer coincided with small-sized minerals resembling nanoparticulate ferrihydrite or goethite. Our results suggest that microbially mediated Fe(II) oxidation dominates in the presence of DOM leading to the formation of nano-sized biogenic Fe(III) (oxyhydr)oxides that might be readily bioavailable and likely important to iron and carbon cycling.
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Affiliation(s)
- Anke Hädrich
- Institute of Biodiversity, Friedrich Schiller University Jena, Dornburger Strasse 159, D-07743 Jena, Germany
| | - Martial Taillefert
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA 30332-0340, USA
| | - Denise M Akob
- Institute of Biodiversity, Friedrich Schiller University Jena, Dornburger Strasse 159, D-07743 Jena, Germany.,Water Resource Mission Area, U.S. Geological Survey, 12201 Sunrise Valley Dr., MS 430, Reston, VA 20192, USA
| | - Rebecca E Cooper
- Institute of Biodiversity, Friedrich Schiller University Jena, Dornburger Strasse 159, D-07743 Jena, Germany
| | - Ulrike Litzba
- Institute of Biodiversity, Friedrich Schiller University Jena, Dornburger Strasse 159, D-07743 Jena, Germany
| | - Friedrich E Wagner
- Department of Physics, Technical University Munich, James Frank Strasse, D-85748 Garching, Germany
| | - Sandor Nietzsche
- Centre of Electron Microscopy, University Hospital Jena, Friedrich Schiller University Jena, Ziegelmühlenweg 1, D-07743 Jena, Germany
| | - Valerian Ciobota
- Institute of Physical Chemistry, Friedrich Schiller University Jena, Helmholtzweg 4, D-07743 Jena, Germany.,Rigaku Analytical Devices, Inc., 30 Upton Drive, Wilmington, MA 01887, USA
| | - Petra Rösch
- Institute of Physical Chemistry, Friedrich Schiller University Jena, Helmholtzweg 4, D-07743 Jena, Germany
| | - Jürgen Popp
- Institute of Photonic Technology, Friedrich Schiller University Jena, Albert-Einstein-Straße 9, D-07745 Jena, Germany
| | - Kirsten Küsel
- Institute of Biodiversity, Friedrich Schiller University Jena, Dornburger Strasse 159, D-07743 Jena, Germany.,German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Deutscher Platz 5e, D-04103 Leipzig, Germany
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13
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Kankanamge NR, Bennett WW, Teasdale PR, Huang J, Welsh DT. A new colorimetric DET technique for determining mm-resolution sulfide porewater distributions and allowing improved interpretation of iron(II) co-distributions. CHEMOSPHERE 2020; 244:125388. [PMID: 31809928 DOI: 10.1016/j.chemosphere.2019.125388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Revised: 11/13/2019] [Accepted: 11/14/2019] [Indexed: 06/10/2023]
Abstract
Measurement of sulfide in pore waters is critical for understanding biogeochemical processes, especially within coastal sediments. Here we report the development of a new colorimetric DET (diffusive equilibration in thin films) technique for determining mm-resolution, two-dimensional sulfide distributions in sediment pore waters. This colorimetric sulfide DET method was based on the standard spectrophotometric methylene blue assay, but modified to allow quantitation of sulfide by computer imaging densitometry. The method detection and effective upper measurement limits of the optimised technique were 3.7 and 1000 μmol L-1, respectively. The optimised sulfide DET method was combined with the colorimetric iron(II) DET method to obtain co-distributions in coastal seagrass (Zostera muelleri) colonised sediment under light and dark conditions. In the dark, seagrass sediments were more reduced than in the light, with large areas being dominated by high porewater sulfide concentrations. These co-distributions were compared with those obtained using the previously described DET-DGT (diffusive gradients in thin films) method for measuring iron(II) and sulfide co-distributions. There was less overlap of iron(II) and sulfide distributions using the sulfide DET as the two DET methods are influenced most by the later hours of deployment, whereas the sulfide-DGT measurement integrates concentrations over the whole deployment period. Overlap was most apparent in very dynamic sediment zones, such as burrow wall sediments.
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Affiliation(s)
- Nadeeka Rathnayake Kankanamge
- Environmental Futures Research Institute and Griffith School of Environment, Griffith University, Gold Coast Campus, QLD, 4215, Australia; Earth and Ocean Sciences, School of Natural Sciences and Ryan Institute, National University of Ireland, Galway, H91 TK33, Ireland
| | - William W Bennett
- Environmental Futures Research Institute and Griffith School of Environment, Griffith University, Gold Coast Campus, QLD, 4215, Australia
| | - Peter R Teasdale
- Natural and Built Environments Research Centre, School of Natural and Built Environments, University of South Australia, SA, 5095, Australia; Future Industries Institute, University of South Australia, SA, 5095, Australia
| | - Jianyin Huang
- Natural and Built Environments Research Centre, School of Natural and Built Environments, University of South Australia, SA, 5095, Australia; Future Industries Institute, University of South Australia, SA, 5095, Australia
| | - David T Welsh
- Environmental Futures Research Institute and Griffith School of Environment, Griffith University, Gold Coast Campus, QLD, 4215, Australia.
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14
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Valero A, Umbría-Salinas K, Wallner-Kersanach M, Andrade CFD, Yabe MJS, Contreira-Pereira L, Wasserman JC, Kuroshima KN, Zhang H. Potential availability of trace metals in sediments in southeastern and southern Brazilian shipyard areas using the DGT technique and chemical extraction methods. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 710:136216. [PMID: 31923659 DOI: 10.1016/j.scitotenv.2019.136216] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 12/18/2019] [Accepted: 12/18/2019] [Indexed: 06/10/2023]
Abstract
Speciation and partitioning of trace metals, from solid to solution phases of sediments, control their bioavailability and thus their potential ecological risk to organisms. Therefore, in order to obtain a broad evaluation of their risk, it is necessary to couple methodologies that are able to assess metal mobility in sediment. In this study, the Diffusive Gradients in Thin Films (DGT) technique and the application of 0.1 M HCl acid extraction methods, together with solid-state voltammetric sensors, were used with the objective of assessing mobility and potential availability of Cr, Cu, Ni, Pb, V and Zn in sediment porewaters and solid sediments in southeastern and southern Brazilian shipyard areas. The highest labile metal concentrations were found in shipyards with the longest histories of operations. Trace metal distributions in porewater and in the solid phase of sediments (labile metals) and significant correlations among metals enabled to distinguish the contribution of anti-fouling paint components. The diffusive flux of every metal measured at the surface of the sediment indicated that CuDGT had the highest flux (3.66E-03 mmol·m-2 d-1) in the shipyard with the longest operating time. Therefore, enrichment was observed for Cu, Pb and Zn in sediments, indicating a possible ecological risk level of 'Effects Range Median' to 'Apparent Effects Threshold' for oyster larvae (Mollusca) (Cu), bivalves (Pb) and the infaunal community (Zn). Probable Effect Concentrations (PEC) to sediment-dwelling biota can be expected as well, related to high concentrations of Cu and Zn in sediment. This study allowed a comprehensive evaluation of potential bioavailability and ecological risk of trace metals in aquatic systems where there is continuous and specific input of these elements. The use of the DGT technique with solid-state voltammetry in the sediment of distinct Brazilian estuarine systems demonstrated its potential to be applied in future environmental network programs.
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Affiliation(s)
- Astolfo Valero
- Laboratório de Hidroquímica, Instituto de Oceanografia, Universidade Federal de Rio Grande, 96203-000, Brazil
| | - Karelys Umbría-Salinas
- Laboratório de Hidroquímica, Instituto de Oceanografia, Universidade Federal de Rio Grande, 96203-000, Brazil
| | - Mônica Wallner-Kersanach
- Laboratório de Hidroquímica, Instituto de Oceanografia, Universidade Federal de Rio Grande, 96203-000, Brazil.
| | - Carlos Ferreira de Andrade
- Laboratório de Hidroquímica, Instituto de Oceanografia, Universidade Federal de Rio Grande, 96203-000, Brazil
| | | | | | | | - Katia Naomi Kuroshima
- Escola do Mar, Ciência e Tecnologia, Universidade do Vale do Itajaí, 88302-202, Brazil
| | - Hao Zhang
- Lancaster Environment Centre, Lancaster University, LA1 4YQ, UK
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15
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Lueder U, Maisch M, Laufer K, Jo Rgensen BB, Kappler A, Schmidt C. Influence of Physical Perturbation on Fe(II) Supply in Coastal Marine Sediments. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:3209-3218. [PMID: 32064861 DOI: 10.1021/acs.est.9b06278] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Iron (Fe) biogeochemistry in marine sediments is driven by redox transformations creating Fe(II) and Fe(III) gradients. As sediments are physically mixed by wave action or bioturbation, Fe gradients re-establish regularly. In order to identify the response of dissolved Fe(II) (Fe2+) and Fe mineral phases toward mixing processes, we performed voltammetric microsensor measurements, sequential Fe extractions, and Mössbauer spectroscopy of 12 h light-dark cycle incubated marine coastal sediment. Fe2+ decreased during 7 days of undisturbed incubation from approximately 400 to 60 μM. In the first 2-4 days of incubation, Fe2+ accumulated up to 100 μM in the top 2 mm due to Fe(III) photoreduction. After physical perturbation at day 7, Fe2+ was re-mobilized reaching concentrations of 320 μM in 30 mm depth, which decreased to below detection limit within 2 days afterward. Mössbauer spectroscopy showed that the relative abundance of metastable iron-sulfur mineral phases (FeSx) increased during initial incubation and decreased together with pyrite (FeS2) after perturbation. We show that Fe2+ mobilization in marine sediments is stimulated by chemical changes caused by physical disturbances impacting the Fe redox distribution. Our study suggests that, in addition to microbial and abiotic Fe(III) reduction, including Fe(III) photoreduction, physical mixing processes induce chemical changes providing sediments and the inhabiting microbial community with Fe2+.
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Affiliation(s)
- Ulf Lueder
- Geomicrobiology Group, Center for Applied Geoscience (ZAG), University of Tuebingen, Sigwartstrasse 10, D-72076 Tuebingen, Germany
| | - Markus Maisch
- Geomicrobiology Group, Center for Applied Geoscience (ZAG), University of Tuebingen, Sigwartstrasse 10, D-72076 Tuebingen, Germany
| | - Katja Laufer
- Center for Geomicrobiology, Department of Bioscience, Aarhus University, Ny Munkegade 114, Building 1540, 8000 Aarhus, Denmark
- GEOMAR Helmholtz Center for Ocean Research Kiel, Wischhofstraße 1-3, 24148 Kiel, Germany
| | - Bo Barker Jo Rgensen
- Center for Geomicrobiology, Department of Bioscience, Aarhus University, Ny Munkegade 114, Building 1540, 8000 Aarhus, Denmark
| | - Andreas Kappler
- Geomicrobiology Group, Center for Applied Geoscience (ZAG), University of Tuebingen, Sigwartstrasse 10, D-72076 Tuebingen, Germany
- Center for Geomicrobiology, Department of Bioscience, Aarhus University, Ny Munkegade 114, Building 1540, 8000 Aarhus, Denmark
| | - Caroline Schmidt
- Geomicrobiology Group, Center for Applied Geoscience (ZAG), University of Tuebingen, Sigwartstrasse 10, D-72076 Tuebingen, Germany
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16
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Lueder U, Jørgensen BB, Kappler A, Schmidt C. Fe(III) Photoreduction Producing Fe aq2+ in Oxic Freshwater Sediment. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:862-869. [PMID: 31886652 DOI: 10.1021/acs.est.9b05682] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Iron(III) (Fe(III)) photoreduction plays an important role in Fe cycling and Fe(II) bioavailability in the upper ocean. Although well described for water columns, it is currently unknown to what extent light impacts the production of dissolved Fe(II) (Fe2+) in aquatic sediments. We performed high-resolution voltammetric microsensor measurements and demonstrated light-induced Fe2+ release in freshwater sediments from Lake Constance. Fe2+ concentrations increased up to 40 μM in the top 3 mm of the sediment during illumination in the visible range of light (400-700 nm), even in the presence of oxygen (100-280 μM). The Fe2+ release was strongly dependent on the organic matter content of the sediment. A lack of photoreduced Fe2+ was measured in sediments with concentrations of organic carbon <6 mg L-1. The simultaneous presence of sedimentary Fe(III) photoreduction besides microbial and abiotic Fe2+ oxidation by oxygen suggests an active Fe redox cycling in the oxic and photic zone of aquatic sediments. Here, we provide evidence for a relevant contribution of Fe(III) photoreduction to the bio-geochemical Fe redox cycle in aquatic freshwater sediments.
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Affiliation(s)
- Ulf Lueder
- Geomicrobiology Group, Center for Applied Geoscience (ZAG) , University of Tuebingen , Sigwartstrasse 10 , D-72076 Tuebingen , Germany
| | - Bo Barker Jørgensen
- Center for Geomicrobiology, Department of Bioscience , Aarhus University , Ny Munkegade 114, Building 1540 , 8000 Aarhus , Denmark
| | - Andreas Kappler
- Geomicrobiology Group, Center for Applied Geoscience (ZAG) , University of Tuebingen , Sigwartstrasse 10 , D-72076 Tuebingen , Germany
- Center for Geomicrobiology, Department of Bioscience , Aarhus University , Ny Munkegade 114, Building 1540 , 8000 Aarhus , Denmark
| | - Caroline Schmidt
- Geomicrobiology Group, Center for Applied Geoscience (ZAG) , University of Tuebingen , Sigwartstrasse 10 , D-72076 Tuebingen , Germany
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17
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Finke N, Simister RL, O'Neil AH, Nomosatryo S, Henny C, MacLean LC, Canfield DE, Konhauser K, Lalonde SV, Fowle DA, Crowe SA. Mesophilic microorganisms build terrestrial mats analogous to Precambrian microbial jungles. Nat Commun 2019; 10:4323. [PMID: 31541087 PMCID: PMC6754388 DOI: 10.1038/s41467-019-11541-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Accepted: 07/03/2019] [Indexed: 12/02/2022] Open
Abstract
Development of Archean paleosols and patterns of Precambrian rock weathering suggest colonization of continents by subaerial microbial mats long before evolution of land plants in the Phanerozoic Eon. Modern analogues for such mats, however, have not been reported, and possible biogeochemical roles of these mats in the past remain largely conceptual. We show that photosynthetic, subaerial microbial mats from Indonesia grow on mafic bedrocks at ambient temperatures and form distinct layers with features similar to Precambrian mats and paleosols. Such subaerial mats could have supported a substantial aerobic biosphere, including nitrification and methanotrophy, and promoted methane emissions and oxidative weathering under ostensibly anoxic Precambrian atmospheres. High C-turnover rates and cell abundances would have made these mats prime locations for early microbial diversification. Growth of landmass in the late Archean to early Proterozoic Eons could have reorganized biogeochemical cycles between land and sea impacting atmospheric chemistry and climate.
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Affiliation(s)
- N Finke
- Departments of Microbiology and Immunology and Earth, Ocean, and Atmospheric Sciences, University of British Columbia, Vancouver, Canada
- Nordic center for earth evolution (NordCEE), University of Southern Denmark, Odense, Denmark
| | - R L Simister
- Departments of Microbiology and Immunology and Earth, Ocean, and Atmospheric Sciences, University of British Columbia, Vancouver, Canada
| | | | - S Nomosatryo
- Research center for Limnology, Indonesian Institute of Sciences (LIPI), Jawa Barat, Indonesia
- GFZ German Research Centre for Geosciences, Potsdam, Germany
| | - C Henny
- Research center for Limnology, Indonesian Institute of Sciences (LIPI), Jawa Barat, Indonesia
| | | | - D E Canfield
- Nordic center for earth evolution (NordCEE), University of Southern Denmark, Odense, Denmark
| | - K Konhauser
- Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, Canada
| | - S V Lalonde
- European Institute for Marine Studies, Technopôle Brest-Iroise, Plouzané, France
| | - D A Fowle
- Department of Geology, University of Kansas, Lawrence, KS, USA
| | - S A Crowe
- Departments of Microbiology and Immunology and Earth, Ocean, and Atmospheric Sciences, University of British Columbia, Vancouver, Canada.
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18
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Hudson JM, MacDonald DJ, Estes ER, Luther GW. A durable and inexpensive pump profiler to monitor stratified water columns with high vertical resolution. Talanta 2019; 199:415-424. [PMID: 30952278 DOI: 10.1016/j.talanta.2019.02.076] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2018] [Revised: 02/20/2019] [Accepted: 02/20/2019] [Indexed: 10/27/2022]
Abstract
A pump profiling system for real time sample collection has been constructed for a cost of <$1000 (USD) and mated with a ship's rosette that has conductivity, temperature, depth (CTD) and other sensors. The system permits the collection of ~15 L of water in one minute without exposure to O2 from air for discrete sampling of chemical, microbial and other constituents as well as for real time analyses using sensors. We also coupled a shipboard voltammetry system with solid-state microelectrodes to detect dissolved O2 and H2S. Electrode O2 detection limits (DL) are ~3 µM and compare well with in situ Clark electrode O2 data (DL ~2 µM) from the ship's CTD rosette system. H2S measurements also were reliable, based on previously compared methods. Best resolution of the profiling system can be as small as its orifice of 2.54 cm (0.0254 m) in a quiet sea state, which is an improvement over the maximum resolution achievable using 10 L Niskin bottles that are 1 m in length.
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Affiliation(s)
- Jeffrey M Hudson
- Department of Civil & Environmental Engineering, University of Delaware, Newark, DE 19716, USA.
| | - Daniel J MacDonald
- School of Marine Science and Policy, University of Delaware, Lewes, DE 19958, USA
| | - Emily R Estes
- School of Marine Science and Policy, University of Delaware, Lewes, DE 19958, USA
| | - George W Luther
- Department of Civil & Environmental Engineering, University of Delaware, Newark, DE 19716, USA; School of Marine Science and Policy, University of Delaware, Lewes, DE 19958, USA.
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19
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Sturm A, Fowle DA, Jones C, Leslie K, Nomosatryo S, Henny C, Canfield DE, Crowe SA. Rates and pathways of CH 4 oxidation in ferruginous Lake Matano, Indonesia. GEOBIOLOGY 2019; 17:294-307. [PMID: 30593722 DOI: 10.1111/gbi.12325] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Revised: 10/16/2018] [Accepted: 10/30/2018] [Indexed: 06/09/2023]
Abstract
This study evaluates rates and pathways of methane (CH4 ) oxidation and uptake using 14 C-based tracer experiments throughout the oxic and anoxic waters of ferruginous Lake Matano. Methane oxidation rates in Lake Matano are moderate (0.36 nmol L-1 day-1 to 117 μmol L-1 day-1 ) compared to other lakes, but are sufficiently high to preclude strong CH4 fluxes to the atmosphere. In addition to aerobic CH4 oxidation, which takes place in Lake Matano's oxic mixolimnion, we also detected CH4 oxidation in Lake Matano's anoxic ferruginous waters. Here, CH4 oxidation proceeds in the apparent absence of oxygen (O2 ) and instead appears to be coupled to some as yet uncertain combination of nitrate ( NO 3 - ), nitrite ( NO 2 - ), iron (Fe) or manganese (Mn), or sulfate ( SO 4 2 - ) reduction. Throughout the lake, the fraction of CH4 carbon that is assimilated vs. oxidized to carbon dioxide (CO2 ) is high (up to 93%), indicating extensive CH4 conversion to biomass and underscoring the importance of CH4 as a carbon and energy source in Lake Matano and potentially other ferruginous or low productivity environments.
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Affiliation(s)
- Arne Sturm
- Department of Geology, University of Kansas, Lawrence, Kansas
| | - David A Fowle
- Department of Geology, University of Kansas, Lawrence, Kansas
| | - CarriAyne Jones
- Department of Microbiology and Immunology and Department of Earth, Ocean, and Atmospheric Sciences, University of British Columbia, Vancouver, British Columbia, Canada
- Nordic Center for Earth Evolution, Institute of Biology, University of Southern Denmark, Odensee, Denmark
| | - Karla Leslie
- Department of Geology, University of Kansas, Lawrence, Kansas
| | - Sulung Nomosatryo
- Research Center for Limnology, Indonesian Institute of Sciences (LIPI), Cibinong-Bogor, Indonesia
| | - Cynthia Henny
- Research Center for Limnology, Indonesian Institute of Sciences (LIPI), Cibinong-Bogor, Indonesia
| | - Donald E Canfield
- Nordic Center for Earth Evolution, Institute of Biology, University of Southern Denmark, Odensee, Denmark
| | - Sean A Crowe
- Department of Microbiology and Immunology and Department of Earth, Ocean, and Atmospheric Sciences, University of British Columbia, Vancouver, British Columbia, Canada
- Nordic Center for Earth Evolution, Institute of Biology, University of Southern Denmark, Odensee, Denmark
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20
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Zhao HQ, Huang SQ, Xu WQ, Wang YR, Wang YX, He CS, Mu Y. Undiscovered Mechanism for Pyrogenic Carbonaceous Matter-Mediated Abiotic Transformation of Azo Dyes by Sulfide. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:4397-4405. [PMID: 30908036 DOI: 10.1021/acs.est.8b06692] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Pyrogenic carbonaceous matter (PCM) catalyzes the transformation of a range of organic pollutants by sulfide in water; however, the mediation mechanisms are not fully understood. In this study, we observed for the first time that the degradation of azo dyes by sulfide initially underwent a lag phase followed by a fast degradation phase. Interestingly, the presence of PCM only reduced the lag phase length of the azo dye decolorization but did not significantly enhance the reaction rate in the fast degradation phase. An analysis of the azo dye reduction and polysulfide formation indicated that PCM facilitated the transformation of sulfide into polysulfides, including disulfide and trisulfide, resulting in fast azo dye reduction. Moreover, the oxygen functional groups of the PCM, especially the quinones, may play an important role in the transformation of sulfide into polysulfides by accelerating the electron transfer. The results of this study provide a better understanding of the PCM-mediated abiotic transformation of organic pollutants by sulfide in anaerobic aqueous environments.
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Affiliation(s)
- Han-Qing Zhao
- CAS Key Laboratory of Urban Pollutant Conversion, Collaborative Innovation Centre of Suzhou Nano Science and Technology, Department of Applied Chemistry , University of Science and Technology of China , Hefei 230026 , China
| | - Shi-Qi Huang
- CAS Key Laboratory of Urban Pollutant Conversion, Collaborative Innovation Centre of Suzhou Nano Science and Technology, Department of Applied Chemistry , University of Science and Technology of China , Hefei 230026 , China
| | - Wen-Qing Xu
- Department of Civil and Environmental Engineering , Villanova University , Villanova , Pennsylvania 19085 , United States
| | - Yi-Ran Wang
- CAS Key Laboratory of Urban Pollutant Conversion, Collaborative Innovation Centre of Suzhou Nano Science and Technology, Department of Applied Chemistry , University of Science and Technology of China , Hefei 230026 , China
| | - Yi-Xuan Wang
- CAS Key Laboratory of Urban Pollutant Conversion, Collaborative Innovation Centre of Suzhou Nano Science and Technology, Department of Applied Chemistry , University of Science and Technology of China , Hefei 230026 , China
| | - Chuan-Shu He
- CAS Key Laboratory of Urban Pollutant Conversion, Collaborative Innovation Centre of Suzhou Nano Science and Technology, Department of Applied Chemistry , University of Science and Technology of China , Hefei 230026 , China
| | - Yang Mu
- CAS Key Laboratory of Urban Pollutant Conversion, Collaborative Innovation Centre of Suzhou Nano Science and Technology, Department of Applied Chemistry , University of Science and Technology of China , Hefei 230026 , China
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Eitel EM, Zhao S, Tang Y, Taillefert M. Effect of Manganese Oxide Aging and Structure Transformation on the Kinetics of Thiol Oxidation. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:13202-13211. [PMID: 30358985 DOI: 10.1021/acs.est.8b03993] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The kinetics and mechanism of thiol oxidation by Mn oxides undergoing dynamic structural transformation under environmentally relevant conditions remain poorly understood. In this study, thiol/disulfide pair concentrations were simultaneously determined in situ using voltammetric microelectrodes during the interaction of four common thiols (cysteine, homocysteine, cysteamine, and glutathione) with fresh and aged δ-MnO2 at pH 7.0. The reaction kinetics was first order with respect to thiol and zero order with respect to Mn oxides. A transient intermediate sulfur surface species observed during the reaction provides evidence for a mechanism involving two successive one-electron transfer steps. The reaction kinetics of fresh and aged δ-MnO2 was investigated with cysteine and compared to that of manganite, a Mn(III) oxyhydroxide phase. The reactivity of aged δ-MnO2 decreased as a result of structural transformation to cryptomelane but remained higher than that of manganite, suggesting the potential roles of transient Mn(III) surface intermediate in promoting the reduction of Mn(IV) in δ-MnO2 and cryptomelane (compared to Mn(III) in manganite). This study demonstrates the importance of correlating Mn oxide mineral structure and redox reactivity and extends the potential for thiols commonly found in sedimentary environments to be utilized as electron shuttles during dissimilatory Mn reduction.
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Affiliation(s)
- Eryn M Eitel
- School of Earth and Atmospheric Sciences , Georgia Institute of Technology , Atlanta , Georgia 30332-0340 , United States
| | - Shiliang Zhao
- School of Earth and Atmospheric Sciences , Georgia Institute of Technology , Atlanta , Georgia 30332-0340 , United States
| | - Yuanzhi Tang
- School of Earth and Atmospheric Sciences , Georgia Institute of Technology , Atlanta , Georgia 30332-0340 , United States
| | - Martial Taillefert
- School of Earth and Atmospheric Sciences , Georgia Institute of Technology , Atlanta , Georgia 30332-0340 , United States
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Jones ME, Nico PS, Ying S, Regier T, Thieme J, Keiluweit M. Manganese-Driven Carbon Oxidation at Oxic-Anoxic Interfaces. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:12349-12357. [PMID: 30260632 DOI: 10.1021/acs.est.8b03791] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The formation of reactive manganese (Mn) species is emerging as a key regulator of carbon oxidation rates, and thus CO2 emissions, in soils and sediments. Many subsurface environments are characterized by steep oxygen gradients, forming oxic-anoxic interfaces that enable rapid redox cycling of Mn. Here, we examined the impact of Mn(II)aq oxidation along oxic-anoxic interfaces on carbon oxidation in soils using laboratory-based diffusion reactors. A combination of cyclic voltammetry, X-ray absorption spectroscopy, and X-ray microprobe imaging revealed a tight coupling between Mn(II)aq oxidation and carbon oxidation at the oxic-anoxic interface. Specifically, zones of Mn(II)aq oxidation across the oxic-anoxic transition also exhibited the greatest lignin oxidation potential, carbon solubilization, and oxidation. Microprobe imaging further revealed that the generation of Mn(III)-dominated precipitates coincided with carbon oxidation. Combined, our findings demonstrate that biotic Mn(II)aq oxidation, specifically the formation of Mn(III) species, contributes to carbon oxidation along oxic-anoxic interfaces in soils and sediments. Our results suggest that we should regard carbon oxidation not merely as a function of molecular composition, which insufficiently predicts rates, but in relation to microenvironments favoring the formation of critically important oxidants such as Mn(III).
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Affiliation(s)
- Morris E Jones
- School of Earth & Sustainability and Stockbridge School of Agriculture , University of Massachusetts , Amherst , Massachusetts 01003 , United States
| | - Peter S Nico
- Earth and Environmental Sciences Area , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
| | - Samantha Ying
- Department of Environmental Sciences , University of California Riverside , Riverside , California 92521 , United States
| | - Tom Regier
- Canadian Synchrotron Lightsource , Saskatoon , Canada
| | - Jürgen Thieme
- NSLS-II, Brookhaven National Laboratory , Brookhaven , New York 11973 , United States
| | - Marco Keiluweit
- School of Earth & Sustainability and Stockbridge School of Agriculture , University of Massachusetts , Amherst , Massachusetts 01003 , United States
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Decrypting the sulfur cycle in oceanic oxygen minimum zones. ISME JOURNAL 2018; 12:2322-2329. [PMID: 29884830 DOI: 10.1038/s41396-018-0149-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2017] [Revised: 01/30/2018] [Accepted: 02/28/2018] [Indexed: 11/08/2022]
Abstract
Here we present ecophysiological studies of the anaerobic sulfide oxidizers considered critical to cryptic sulfur cycling in oceanic oxygen minimum zones (OMZs). We find that HS- oxidation rates by microorganisms in the Chilean OMZ offshore from Dichato are sufficiently rapid (18 nM h-1), even at HS- concentrations well below 100 nM, to oxidize all sulfide produced during sulfate reduction in OMZs. Even at 100 nM, HS- is well below published half-saturation concentrations and we conclude that the sulfide-oxidizing bacteria in OMZs (likely the SUP05/ARTIC96BD lineage of the gammaproteobacteria) have high-affinity (>105 g-1 wet cells h-1) sulfur uptake systems. These specific affinities for sulfide are higher than those recorded for any other organism on any other substrate. Such high affinities likely allow anaerobic sulfide oxidizers to maintain vanishingly low sulfide concentrations in OMZs driving marine cryptic sulfur cycling. If more broadly distributed, such high-affinity sulfur biochemistry could facilitate sulfide-based metabolisms and prominent S-cycles in many other ostensibly sulfide-free environments.
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Superville PJ, Ivanovsky A, Bhurtun P, Prygiel J, Billon G. Diel cycles of reduced manganese and their seasonal variability in the Marque River (northern France). THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 624:918-925. [PMID: 29275254 DOI: 10.1016/j.scitotenv.2017.12.189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Revised: 12/12/2017] [Accepted: 12/17/2017] [Indexed: 06/07/2023]
Abstract
Electrolabile reduced manganese (II) has been monitored by voltammetry during two periods of one month in summer 2014 and at the end of winter 2015 in a small river (the Marque River) located in northern France and going through a suburban area with agricultural activities. Diel variations, evolution within the one-month periods and seasonal differences have been observed. Taking into consideration the multiple physical, biological and chemical reactions regulating manganese speciation in aquatic systems, it has been demonstrated that manganese speciation is probably controlled by the competition of two antagonist reactions: the photoreduction of manganese oxides (in broad sense and represented thereafter by MnOx) and the biotic oxidation of Mn(II). Depending on the season, the biological activity in the river and the amount of luminosity reaching the MnOx, either the production of reduced labile Mn(II) or the precipitation of MnOx can become the dominant process. Other punctual events such as the drop of oxygen concentration due to large inputs of biodegradable organic matter and eutrophication phenomena, rainy events and high luminosity periods can also affect the behaviour of dissolved Mn(II) in the Marque River and so, of other contaminants.
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Affiliation(s)
- Pierre-Jean Superville
- LASIR CNRS UMR 8516, Université de Lille, Sciences et Technologies, 59655 Villeneuve d'Ascq Cedex, France.
| | - Anastasia Ivanovsky
- LASIR CNRS UMR 8516, Université de Lille, Sciences et Technologies, 59655 Villeneuve d'Ascq Cedex, France
| | - Pratima Bhurtun
- LASIR CNRS UMR 8516, Université de Lille, Sciences et Technologies, 59655 Villeneuve d'Ascq Cedex, France
| | - Jean Prygiel
- LASIR CNRS UMR 8516, Université de Lille, Sciences et Technologies, 59655 Villeneuve d'Ascq Cedex, France; Agence de l'Eau Artois-Picardie, 200 rue Marceline, 59500 Douai, France
| | - Gabriel Billon
- LASIR CNRS UMR 8516, Université de Lille, Sciences et Technologies, 59655 Villeneuve d'Ascq Cedex, France
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Microbially Mediated Coupling of Fe and N Cycles by Nitrate-Reducing Fe(II)-Oxidizing Bacteria in Littoral Freshwater Sediments. Appl Environ Microbiol 2018; 84:AEM.02013-17. [PMID: 29101195 DOI: 10.1128/aem.02013-17] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Accepted: 10/31/2017] [Indexed: 11/20/2022] Open
Abstract
Nitrate-reducing iron(II)-oxidizing bacteria have been known for approximately 20 years. There has been much debate as to what extent the reduction of nitrate and the oxidation of ferrous iron are coupled via enzymatic pathways or via abiotic processes induced by nitrite formed by heterotrophic denitrification. The aim of the present study was to assess the coupling of nitrate reduction and iron(II) oxidation by monitoring changes in substrate concentrations, as well as in the activity of nitrate-reducing bacteria in natural littoral freshwater sediment, in response to stimulation with nitrate and iron(II). In substrate-amended microcosms, we found that the biotic oxidation of ferrous iron depended on the simultaneous microbial reduction of nitrate. Additionally, the abiotic oxidation of ferrous iron by nitrite in sterilized sediment was not fast enough to explain the iron oxidation rates observed in microbially active sediment. Furthermore, the expression levels of genes coding for enzymes crucial for nitrate reduction were in some setups stimulated by the presence of ferrous iron. These results indicate that there is a direct influence of ferrous iron on bacterial denitrification and support the hypothesis that microbial nitrate reduction is stimulated by biotic iron(II) oxidation.IMPORTANCE The coupling of nitrate reduction and Fe(II) oxidation affects the environment at a local scale, e.g., by changing nutrient or heavy metal mobility in soils due to the formation of Fe(III) minerals, as well as at a global scale, e.g., by the formation of the primary greenhouse gas nitrous oxide. Although the coupling of nitrate reduction and Fe(II) oxidation was reported 20 years ago and has been studied intensively since then, the underlying mechanisms still remain unknown. One of the main knowledge gaps is the extent of enzymatic Fe(II) oxidation coupled to nitrate reduction, which has frequently been questioned in the literature. In the present study, we provide evidence for microbially mediated nitrate-reducing Fe(II) oxidation in freshwater sediments. This evidence is based on the rates of nitrate reduction and Fe(II) oxidation determined in microcosm incubations and on the effect of iron on the expression of genes required for denitrification.
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26
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Lueder U, Druschel G, Emerson D, Kappler A, Schmidt C. Quantitative analysis of O2 and Fe2+ profiles in gradient tubes for cultivation of microaerophilic Iron(II)-oxidizing bacteria. FEMS Microbiol Ecol 2017; 94:4693834. [DOI: 10.1093/femsec/fix177] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Accepted: 12/04/2017] [Indexed: 11/14/2022] Open
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Rathnayake Kankanamge N, Bennett WW, Teasdale PR, Huang J, Welsh DT. Comparing in situ colorimetric DET and DGT techniques with ex situ core slicing and centrifugation for measuring ferrous iron and dissolved sulfide in coastal sediment pore waters. CHEMOSPHERE 2017; 188:119-129. [PMID: 28881239 DOI: 10.1016/j.chemosphere.2017.08.144] [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: 05/29/2017] [Revised: 08/25/2017] [Accepted: 08/28/2017] [Indexed: 06/07/2023]
Abstract
In productive coastal sediments the separation between different biogeochemical zones (e.g. oxic, iron(III)-reducing and sulfate-reducing) may be on the scale of millimetres. Conventional measurement techniques simply cannot resolve changes in pore water solute concentrations over such small distances. The diffusive equilibration in thin films (DET) and the diffusive gradients in thin films (DGT) techniques allow in situ determination of pore water solute concentration profiles with one-dimensional profiles and/or two-dimensional distributions on the millimetre scale. Here we compare measurements of pore water iron(II) and sulfide using conventional core sampling (slicing and centrifugation) and colorimetric DET-DGT techniques. DET-DGT samplers were deployed within replicate sediment cores from three different sites, which were processed by slicing and centrifugation following retrieval of the samplers, so that the measurements were approximately co-located. Iron(II) concentrations were determined by DET at all three sites (0.3-262 μmol L-1), while dissolved sulfide was consistently measured by DGT at one site only (0.003-112 μmol L-1). Pore water concentrations of iron(II) and sulfide determined conventionally following pore water extraction (iron(II); 0.4-88 μmol L-1 and sulfide; 0.05-36 μmol L-1), were systematically lower than the colorimetric DET and DGT measurements in the same sample. This underestimation was most likely due to the mixing of sediment from different biogeochemical zones during pore water extraction, which resulted in the precipitation of iron(II) and sulfide. This study shows that conventional pore water extraction methods can be unreliable for the determination of redox-active solutes due to artefacts associated with pore water mixing.
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Affiliation(s)
| | - William W Bennett
- Environmental Futures Research Institute, Griffith University, Gold Coast Campus, QLD, 4215, Australia
| | - Peter R Teasdale
- Natural and Built Environments Research Centre, School of Natural and Built Environments, University of South Australia, South Australia, 5095, Australia; Future Industries Institute, University of South Australia, SA, 5095, Australia
| | - Jianyin Huang
- Natural and Built Environments Research Centre, School of Natural and Built Environments, University of South Australia, South Australia, 5095, Australia; Future Industries Institute, University of South Australia, SA, 5095, Australia
| | - David T Welsh
- Environmental Futures Research Institute, Griffith University, Gold Coast Campus, QLD, 4215, Australia.
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28
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Bone SE, Cahill MR, Jones ME, Fendorf S, Davis J, Williams KH, Bargar JR. Oxidative Uranium Release from Anoxic Sediments under Diffusion-Limited Conditions. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:11039-11047. [PMID: 28876920 DOI: 10.1021/acs.est.7b02241] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Uranium (U) contamination occurs as a result of mining and ore processing; often in alluvial aquifers that contain organic-rich, reduced sediments that accumulate tetravalent U, U(IV). Uranium(IV) is sparingly soluble, but may be mobilized upon exposure to nitrate (NO3-) and oxygen (O2), which become elevated in groundwater due to seasonal fluctuations in the water table. The extent to which oxidative U mobilization can occur depends upon the transport properties of the sediments, the rate of U(IV) oxidation, and the availability of inorganic reductants and organic electron donors that consume oxidants. We investigated the processes governing U release upon exposure of reduced sediments to artificial groundwater containing O2 or NO3- under diffusion-limited conditions. Little U was mobilized during the 85-day reaction, despite rapid diffusion of groundwater within the sediments and the presence of nonuraninite U(IV) species. The production of ferrous iron and sulfide in conjunction with rapid oxidant consumption suggested that the sediments harbored large concentrations of bioavailable organic carbon that fueled anaerobic microbial respiration and stabilized U(IV). Our results suggest that seasonal influxes of O2 and NO3- may cause only localized mobilization of U without leading to export of U from the reducing sediments when ample organic carbon is present.
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Affiliation(s)
- Sharon E Bone
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory , Menlo Park, California 94025, United States
| | | | - Morris E Jones
- Stanford University , Stanford, California 94305, United States
| | - Scott Fendorf
- Stanford University , Stanford, California 94305, United States
| | - James Davis
- U.S. Geological Survey, Menlo Park, California 94025, United States
| | - Kenneth H Williams
- Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
| | - John R Bargar
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory , Menlo Park, California 94025, United States
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29
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Castañeda AD, Brenes NJ, Kondajji A, Crooks RM. Detection of microRNA by Electrocatalytic Amplification: A General Approach for Single-Particle Biosensing. J Am Chem Soc 2017; 139:7657-7664. [DOI: 10.1021/jacs.7b03648] [Citation(s) in RCA: 100] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Alma D. Castañeda
- Department of Chemistry and
Center for Electrochemistry, The University of Texas at Austin, 105 E. 24th Street, Stop A5300, Austin, Texas 78712-1224, United States
| | - Nicholas J. Brenes
- Department of Chemistry and
Center for Electrochemistry, The University of Texas at Austin, 105 E. 24th Street, Stop A5300, Austin, Texas 78712-1224, United States
| | - Aditya Kondajji
- Department of Chemistry and
Center for Electrochemistry, The University of Texas at Austin, 105 E. 24th Street, Stop A5300, Austin, Texas 78712-1224, United States
| | - Richard M. Crooks
- Department of Chemistry and
Center for Electrochemistry, The University of Texas at Austin, 105 E. 24th Street, Stop A5300, Austin, Texas 78712-1224, United States
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30
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Yücel M, Sommer S, Dale AW, Pfannkuche O. Microbial Sulfide Filter along a Benthic Redox Gradient in the Eastern Gotland Basin, Baltic Sea. Front Microbiol 2017; 8:169. [PMID: 28232821 PMCID: PMC5299003 DOI: 10.3389/fmicb.2017.00169] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Accepted: 01/24/2017] [Indexed: 11/17/2022] Open
Abstract
The sediment-water interface is an important site for material exchange in marine systems and harbor unique microbial habitats. The flux of nutrients, metals, and greenhouse gases at this interface may be severely dampened by the activity of microorganisms and abiotic redox processes, leading to the “benthic filter” concept. In this study, we investigate the spatial variability, mechanisms and quantitative importance of a microbially-dominated benthic filter for dissolved sulfide in the Eastern Gotland Basin (Baltic Sea) that is located along a dynamic redox gradient between 65 and 173 m water depth. In August-September 2013, high resolution (0.25 mm minimum) vertical microprofiles of redox-sensitive species were measured in surface sediments with solid-state gold-amalgam voltammetric microelectrodes. The highest sulfide consumption (2.73–3.38 mmol m−2 day−1) occurred within the top 5 mm in sediments beneath a pelagic hypoxic transition zone (HTZ, 80–120 m water depth) covered by conspicuous white bacterial mats of genus Beggiatoa. A distinct voltammetric signal for polysulfides, a transient sulfur oxidation intermediate, was consistently observed within the mats. In sediments under anoxic waters (>140 m depth), signals for Fe(II) and aqueous FeS appeared below a subsurface maximum in dissolved sulfide, indicating a Fe(II) flux originating from older sediments presumably deposited during the freshwater Ancylus Lake that preceded the modern Baltic Sea. Our results point to a dynamic benthic sulfur cycling in Gotland Basin where benthic sulfide accumulation is moderated by microbial sulfide oxidation at the sediment surface and FeS precipitation in deeper sediment layers. Upscaling our fluxes to the Baltic Proper; we find that up to 70% of the sulfide flux (2281 kton yr−1) toward the sediment-seawater interface in the entire basin can be consumed at the microbial mats under the HTZ (80–120 m water depth) while only about 30% the sulfide flux effuses to the bottom waters (>120 m depth). This newly described benthic filter for the Gotland Basin must play a major role in limiting the accumulation of sulfide in and around the deep basins of the Baltic Sea.
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Affiliation(s)
- Mustafa Yücel
- GEOMAR Helmholtz Centre for Ocean Research KielKiel, Germany; Middle East Technical University, Institute of Marine SciencesErdemli, Turkey
| | - Stefan Sommer
- GEOMAR Helmholtz Centre for Ocean Research Kiel Kiel, Germany
| | - Andrew W Dale
- GEOMAR Helmholtz Centre for Ocean Research Kiel Kiel, Germany
| | - Olaf Pfannkuche
- GEOMAR Helmholtz Centre for Ocean Research Kiel Kiel, Germany
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31
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Silwana B, Van Der Horst C, Iwuoha E, Somerset V. A brief review on recent developments of electrochemical sensors in environmental application for PGMs. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART A, TOXIC/HAZARDOUS SUBSTANCES & ENVIRONMENTAL ENGINEERING 2016; 51:1233-1247. [PMID: 27715654 DOI: 10.1080/10934529.2016.1212562] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
This study offers a brief review of the latest developments and applications of electrochemical sensors for the detection of Platinum Group Metals (PGMs) using electrochemical sensors. In particular, significant advances in electrochemical sensors made over the past decade and sensing methodologies associated with the introduction of nanostructures are highlighted. Amongst a variety of detection methods that have been developed for PGMs, nanoparticles offer the unrivaled merits of high sensitivity. Rapid detection of PGMs is a key step to promote improvement of the public health and individual quality of life. Conventional methods to detect PGMs rely on time-consuming and labor intensive procedures such as extraction, isolation, enrichment, counting, etc., prior to measurement. This results in laborious sample preparation and testing over several days. This study reviewed the state-of-the-art application of nanoparticles (NPs) in electrochemical analysis of environmental pollutants. This review is intended to provide environmental scientists and engineers an overview of current rapid detection methods, a close look at the nanoparticles based electrodes and identification of knowledge gaps and future research needs. We summarize electrodes that have been used in the past for detection of PGMs. We describe several examples of applications in environmental electrochemical sensors and performance in terms of sensitivity and selectivity for all the sensors utilized for PGMs detection. NPs have promising potential to increase competitiveness of electrochemical sensors in environmental monitoring, though this review has focused mainly on sensors used in the past decade for PGMs detection. This review therefore provides a synthesis of outstanding performances in recent advances in the nanosensor application for PGMs determination.
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Affiliation(s)
- Bongiwe Silwana
- a Natural Resources and the Environment (NRE), Council for Scientific and Industrial Research (CSIR) , Stellenbosch , South Africa
- b SensorLab , Department of Chemistry , University of the Western Cape , Bellville , South Africa
| | - Charlton Van Der Horst
- a Natural Resources and the Environment (NRE), Council for Scientific and Industrial Research (CSIR) , Stellenbosch , South Africa
- b SensorLab , Department of Chemistry , University of the Western Cape , Bellville , South Africa
| | - Emmanuel Iwuoha
- b SensorLab , Department of Chemistry , University of the Western Cape , Bellville , South Africa
| | - Vernon Somerset
- a Natural Resources and the Environment (NRE), Council for Scientific and Industrial Research (CSIR) , Stellenbosch , South Africa
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32
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Lefèvre CT, Howse PA, Schmidt ML, Sabaty M, Menguy N, Luther GW, Bazylinski DA. Growth of magnetotactic sulfate-reducing bacteria in oxygen concentration gradient medium. ENVIRONMENTAL MICROBIOLOGY REPORTS 2016; 8:1003-1015. [PMID: 27701830 DOI: 10.1111/1758-2229.12479] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Although dissimilatory sulfate-reducing bacteria (SRB) are generally described as strictly anaerobic organisms with regard to growth, several reports have shown that some SRB, particularly Desulfovibrio species, are quite resistant to O2 . For example, SRB remain viable in many aerobic environments while some even reduce O2 to H2 O. However, reproducible aerobic growth of SRB has not been unequivocally documented. Desulfovibrio magneticus is a SRB that is also a magnetotactic bacterium (MTB). MTB biomineralize magnetosomes which are intracellular, membrane-bounded, magnetic iron mineral crystals. The ability of D. magneticus to grow aerobically in several different media under air where an O2 concentration gradient formed, or under O2 -free N2 gas was tested. Under air, cells grew as a microaerophilic band of cells at the oxic-anoxic interface in media lacking sulfate. These results show that D. magneticus is capable of aerobic growth with O2 as a terminal electron acceptor. This is the first report of consistent, reproducible aerobic growth of SRB. This finding is critical in determining important ecological roles SRB play in the environment. Interestingly, the crystal structure of the magnetite crystals of D. magneticus grown under microaerobic conditions showed significant differences compared with those produced anaerobically providing more evidence that environmental parameters influence magnetosome formation.
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Affiliation(s)
- Christopher T Lefèvre
- CNRS/CEA/Aix-Marseille Université UMR7265 Institut de biosciences et biotechnologies Laboratoire de Bioénergétique Cellulaire, Saint Paul lez Durance, 13108, France
| | - Paul A Howse
- School of Life Sciences, University of Nevada at Las Vegas, Las Vegas, NV, 89154-4004, USA
| | - Marian L Schmidt
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI, USA
| | - Monique Sabaty
- CNRS/CEA/Aix-Marseille Université UMR7265 Institut de biosciences et biotechnologies Laboratoire de Bioénergétique Cellulaire, Saint Paul lez Durance, 13108, France
| | - Nicolas Menguy
- Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, Sorbonne Universités, Université Pierre et Marie Curie, UMR 7590 CNRS, Institut de Recherche pour le Développement UMR 206, Museum National d'Histoire Naturelle, Paris Cedex 05, 75252, France
| | - George W Luther
- School of Marine Science and Policy, University of Delaware, 700 Pilottown Rd. Lewes, DE, 19958, USA
| | - Dennis A Bazylinski
- School of Life Sciences, University of Nevada at Las Vegas, Las Vegas, NV, 89154-4004, USA
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33
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Walczak AB, Kafantaris FCA, Druschel GK, Yee N, Young LY. Transformation of galena to pyromorphite produces bioavailable sulfur for neutrophilic chemoautotrophy. GEOBIOLOGY 2016; 14:599-606. [PMID: 27418402 DOI: 10.1111/gbi.12199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Accepted: 05/22/2016] [Indexed: 06/06/2023]
Abstract
The aqueous concentration of lead [Pb(II)] in geochemical environments is controlled by the solubility of Pb-bearing minerals and their weathering products. In contaminated soils, a common method for in situ stabilization of Pb(II) is the addition of phosphate to convert more redox sensitive sulfide minerals into sparingly soluble pyromorphite [Pb5 (PO4 )3 X]. In this study, we conducted experimental studies to investigate the fate of reduced sulfur during the conversion of galena [PbS] to chloropyromorphite [Pb5 (PO4 )3 Cl]. Powder X-ray diffraction analysis indicated that the reaction of phosphate with galena under oxic conditions resulted in the oxidation of sulfide and formation of elemental sulfur [S8 ]. Under oxic abiotic conditions, the S8 was retained in the solid phase, and negligible concentrations of sulfur as sulfide and thiosulfate were detected in the aqueous phase and only a small amount of sulfate. When PbS reacted in the presence of the chemoautotrophic organism Bosea sp. WAO, the S8 in the secondary mineral was oxidized to sulfate. Strain WAO produced significantly more sulfate from the secondary S8 than from the primary galena. Microscopic analysis of mineral-microbe aggregates on mineral-embedded slide cultures showed that the organism was colocalized and increased in biomass over time on the secondary mineral surface supporting a microbial role. The results of this study indicate that stimulation of sulfur-oxidizing activity may be a direct consequence of phosphate amendments to Pb(II)-contaminated soils.
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Affiliation(s)
- A B Walczak
- Department of Environmental Sciences, Rutgers University, New Brunswick, NJ, USA
| | - F-C A Kafantaris
- Department of Earth Sciences, Indiana University-Purdue University, Indianapolis, IN, USA
| | - G K Druschel
- Department of Earth Sciences, Indiana University-Purdue University, Indianapolis, IN, USA
| | - N Yee
- Department of Environmental Sciences, Rutgers University, New Brunswick, NJ, USA
| | - L Y Young
- Department of Environmental Sciences, Rutgers University, New Brunswick, NJ, USA.
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Afzali F, Arbab Zavar MH, Rounaghi G, Ashraf N. Gold digital versatile disc platform modified with nano-porous mercury/gold amalgam as a solid-state disposable electrochemical sensor for detection of para -nitrophenol. Electrochim Acta 2016. [DOI: 10.1016/j.electacta.2016.05.125] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Chan CS, McAllister SM, Leavitt AH, Glazer BT, Krepski ST, Emerson D. The Architecture of Iron Microbial Mats Reflects the Adaptation of Chemolithotrophic Iron Oxidation in Freshwater and Marine Environments. Front Microbiol 2016; 7:796. [PMID: 27313567 PMCID: PMC4888753 DOI: 10.3389/fmicb.2016.00796] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Accepted: 05/11/2016] [Indexed: 11/13/2022] Open
Abstract
Microbes form mats with architectures that promote efficient metabolism within a particular physicochemical environment, thus studying mat structure helps us understand ecophysiology. Despite much research on chemolithotrophic Fe-oxidizing bacteria, Fe mat architecture has not been visualized because these delicate structures are easily disrupted. There are striking similarities between the biominerals that comprise freshwater and marine Fe mats, made by Beta- and Zetaproteobacteria, respectively. If these biominerals are assembled into mat structures with similar functional morphology, this would suggest that mat architecture is adapted to serve roles specific to Fe oxidation. To evaluate this, we combined light, confocal, and scanning electron microscopy of intact Fe microbial mats with experiments on sheath formation in culture, in order to understand mat developmental history and subsequently evaluate the connection between Fe oxidation and mat morphology. We sampled a freshwater sheath mat from Maine and marine stalk and sheath mats from Loihi Seamount hydrothermal vents, Hawaii. Mat morphology correlated to niche: stalks formed in steeper O2 gradients while sheaths were associated with low to undetectable O2 gradients. Fe-biomineralized filaments, twisted stalks or hollow sheaths, formed the highly porous framework of each mat. The mat-formers are keystone species, with nascent marine stalk-rich mats comprised of novel and uncommon Zetaproteobacteria. For all mats, filaments were locally highly parallel with similar morphologies, indicating that cells were synchronously tracking a chemical or physical cue. In the freshwater mat, cells inhabited sheath ends at the growing edge of the mat. Correspondingly, time lapse culture imaging showed that sheaths are made like stalks, with cells rapidly leaving behind an Fe oxide filament. The distinctive architecture common to all observed Fe mats appears to serve specific functions related to chemolithotrophic Fe oxidation, including (1) removing Fe oxyhydroxide waste without entombing cells or clogging flow paths through the mat and (2) colonizing niches where Fe(II) and O2 overlap. This work improves our understanding of Fe mat developmental history and how mat morphology links to metabolism. We can use these results to interpret biogenicity, metabolism, and paleoenvironmental conditions of Fe microfossil mats, which would give us insight into Earth's Fe and O2 history.
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Affiliation(s)
- Clara S Chan
- School of Marine Science and Policy, University of DelawareNewark, DE, USA; Geological Sciences, University of DelawareNewark, DE, USA
| | - Sean M McAllister
- School of Marine Science and Policy, University of DelawareNewark, DE, USA; Geological Sciences, University of DelawareNewark, DE, USA
| | - Anna H Leavitt
- Bigelow Laboratory for Ocean Sciences East Boothbay, ME, USA
| | - Brian T Glazer
- Department of Oceanography, University of Hawaii Honolulu, HI, USA
| | - Sean T Krepski
- Geological Sciences, University of Delaware Newark, DE, USA
| | - David Emerson
- Bigelow Laboratory for Ocean Sciences East Boothbay, ME, USA
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Wang C, Zhai W, Shan B. Oxygen microprofile in the prepared sediments and its implication for the sediment oxygen consuming process in a heavily polluted river of China. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2016; 23:8634-8643. [PMID: 26797955 DOI: 10.1007/s11356-016-6087-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Accepted: 01/11/2016] [Indexed: 06/05/2023]
Abstract
Dissolved oxygen (DO) microprofiles of prepared sediments from 24 sampling sites in the Fuyang River were measured using a gold amalgam microelectrode in this study. The measured microprofiles can be divided into four types. In type I profiles, DO kept constant in the overlying water and decreased smoothly in the pore water; in type II profile, DO showed fluctuation in the pore water; in type III profiles, DO showed peak in the SWI; in type IV profiles, DO decreased obviously in the overlying water. Type I profiles indicated the absence of benthic organisms and thus the degradation of the sediment habitat. Type II and III profiles indicated the activity of benthic animal and epipelic algae, which is common in the healthy aquatic sediment. Type IV profiles indicated that the excessive accumulation of pollutants in the sediment and thus the serious sediment pollution. There are nine sites showing type I profile, three sites showing type II profile, nine sites showing type III profile, and three sites showing type IV profile in the Fuyang River. The dominance of type I and appearance of type IV indicated that sediment oxygen consumption processes in the Fuyang River were strongly influenced by the sediment pollutants release and the vanish of benthic organisms. The pharmacy, metallurgy, and curriery industries may contribute to the sediment deterioration and thus to the occurrence of type I and type IV oxygen profiles in the Fuyang River.
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Affiliation(s)
- Chao Wang
- Changjiang Water Resource Protection Institution, Wuhan, 430051, China.
| | - Wanying Zhai
- Yangtze Valley Water Environment Monitoring Center, Wuhan, 430010, China
| | - Baoqing Shan
- State Key Laboratory on Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China
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Beinart RA, Gartman A, Sanders JG, Luther GW, Girguis PR. The uptake and excretion of partially oxidized sulfur expands the repertoire of energy resources metabolized by hydrothermal vent symbioses. Proc Biol Sci 2016; 282:20142811. [PMID: 25876848 PMCID: PMC4426611 DOI: 10.1098/rspb.2014.2811] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Symbiotic associations between animals and chemoautotrophic bacteria crowd around hydrothermal vents. In these associations, symbiotic bacteria use chemical reductants from venting fluid for the energy to support autotrophy, providing primary nutrition for the host. At vents along the Eastern Lau Spreading Center, the partially oxidized sulfur compounds (POSCs) thiosulfate and polysulfide have been detected in and around animal communities but away from venting fluid. The use of POSCs for autotrophy, as an alternative to the chemical substrates in venting fluid, could mitigate competition in these communities. To determine whether ESLC symbioses could use thiosulfate to support carbon fixation or produce POSCs during sulfide oxidation, we used high-pressure, flow-through incubations to assess the productivity of three symbiotic mollusc genera—the snails Alviniconcha spp. and Ifremeria nautilei, and the mussel Bathymodiolus brevior—when oxidizing sulfide and thiosulfate. Via the incorporation of isotopically labelled inorganic carbon, we found that the symbionts of all three genera supported autotrophy while oxidizing both sulfide and thiosulfate, though at different rates. Additionally, by concurrently measuring their effect on sulfur compounds in the aquaria with voltammetric microelectrodes, we showed that these symbioses excreted POSCs under highly sulfidic conditions, illustrating that these symbioses could represent a source for POSCs in their habitat. Furthermore, we revealed spatial disparity in the rates of carbon fixation among the animals in our incubations, which might have implications for the variability of productivity in situ. Together, these results re-shape our thinking about sulfur cycling and productivity by vent symbioses, demonstrating that thiosulfate may be an ecologically important energy source for vent symbioses and that they also likely impact the local geochemical regime through the excretion of POSCs.
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Affiliation(s)
- R A Beinart
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02136, USA
| | - A Gartman
- School of Marine Science and Policy, College of Earth, Ocean and Environment, University of Delaware, Lewes, MD, USA
| | - J G Sanders
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02136, USA
| | - G W Luther
- School of Marine Science and Policy, College of Earth, Ocean and Environment, University of Delaware, Lewes, MD, USA
| | - P R Girguis
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02136, USA
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Wang C, Zhai W, Yin W, Shan B. The limiting role of oxygen penetration in sediment nitrification. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2015; 22:10910-10918. [PMID: 25772879 DOI: 10.1007/s11356-015-4300-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Accepted: 03/02/2015] [Indexed: 06/04/2023]
Abstract
Oxygen penetration is a key determinant of sediment nitrification rates. In this study, we analyzed the effect of oxygen penetration on the sediment nitrification rate based on sediment oxygen profiles. Six sediments were designed to produce different oxygen profiles by adding different amounts of silica gel to the collected river mud. The oxygen profiles in the sediment were detected using a voltammetric microelectrode. With increased mud content, the sediment oxygen penetration depth decreased from 8.3 to 2.6 mm, and the oxygen concentration in the overlying water and at the sediment-water interface also showed a decreasing trend. The measured nitrification rate displayed a quadratic pattern that changed with the increase in mud content. Based on the detected oxygen profiles, the nitrification rate at each depth was calculated and summed to obtain the bulk sediment nitrification rate. The bulk sediment nitrification rate showed a consistently changing pattern with the measured rate. Oxygen profiles used to calculate nitrification rates could be approximated by the penetration depth (δ). The resulting nitrification model based on δ could explain the limiting role of oxygen penetration in sediment nitrification.
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Affiliation(s)
- Chao Wang
- Changjiang Water Resource Protection Institution, Wuhan, 430051, China,
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Simultaneous Voltammetric/Amperometric Determination of Sulfide and Nitrite in Water at BDD Electrode. SENSORS 2015; 15:14526-38. [PMID: 26102487 PMCID: PMC4507588 DOI: 10.3390/s150614526] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Accepted: 05/22/2015] [Indexed: 11/17/2022]
Abstract
This work reported new voltammetric/amperometric-based protocols using a commercial boron-doped diamond (BDD) electrode for simple and fast simultaneous detection of sulfide and nitrite from water. Square-wave voltammetry operated under the optimized working conditions of 0.01 V step potential, 0.5 V modulation amplitude and 10 Hz frequency allowed achieving the best electroanalytical parameters for the simultaneous detection of nitrite and sulfide. For practical in-field detection applications, the multiple-pulsed amperometry technique was operated under optimized conditions, i.e., −0.5 V/SCE for a duration of 0.3 s as conditioning step, +0.85 V/SCE for a duration of 3 s that assure the sulfide oxidation and +1.25 V/SCE for a duration of 0.3 s, where the nitrite oxidation occurred, which allowed the simultaneously detection of sulfide and nitrite without interference between them. Good accuracy was found for this protocol in comparison with standardized methods for each anion. Also, no interference effect was found for the cation and anion species, which are common in the water matrix.
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Yasadi K, Pinheiro JP, Zielińska K, Town RM, van Leeuwen HP. Partitioning of humic acids between aqueous solution and hydrogel. 3. Microelectrodic dynamic speciation analysis of free and bound humic metal complexes in the gel phase. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:1737-1745. [PMID: 25580682 DOI: 10.1021/la504885v] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The hydrogel/water partitioning of the various species in the cadmium(II)/soil humic acid (HA) system is studied for two types of gel, using in situ microelectrodic voltammetry. Under the conditions of this work, with HA particles of ca. 25 and 125 nm radius, the CdHA complex is shown to be close to nonlabile toward a 12.5 μm radius microelectrode. This implies that its kinetic contribution to Cd(2+) reduction at the medium/microelectrode interface is practically negligible. The polyacrylamide (PAAm) gels equilibrate with the aqueous medium under significant sorption of HA at the gel backbone/gel medium interface, which in turn leads to induced sorption of Cd(II) in the form of immobilized gel-bound CdHA. The rather high total Cd content of the PAAm gel suggests that the binding of Cd(2+) by the hydrophobically gel-bound HA is stronger than that for dispersed HA particles. Still, the intraparticulate speciation of Cd(II) over Cd(2+) and CdHA corresponds to an intrinsic stability constant similar to that for simple monocarboxylate ligands such as acetate. Alginate gels are negatively charged, and their free [Cd(aq)(2+)] is higher than that in the medium by the corresponding Donnan coefficient. On top of that, Cd(2+) is specifically sorbed by the gel backbone/gel medium interface to reach accumulation factors as high as a few tens. HA and CdHA accumulate in the outer 20 μm film of gel at the gel/water interface of both gels, but they do not penetrate into the bulk of the alginate gel. Overall, the gel/water interface dictates drastic changes in the speciation of Cd/HA as compared to the aqueous medium, with distinct features for each individual type of gel. The results have broad significance, for example, for predictions of reactivity and bioavailability of metal species which inherently involve partitioning and diffusion into diverse gel layers such as biointerfacial cell walls, biofilm matrices, and mucous membranes.
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Affiliation(s)
- Kamuran Yasadi
- Laboratory of Physical Chemistry and Colloid Science, Wageningen University , Dreijenplein 6, 6703 HB Wageningen, The Netherlands
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41
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Wilbanks EG, Jaekel U, Salman V, Humphrey PT, Eisen JA, Facciotti MT, Buckley DH, Zinder SH, Druschel GK, Fike DA, Orphan VJ. Microscale sulfur cycling in the phototrophic pink berry consortia of the Sippewissett Salt Marsh. Environ Microbiol 2014; 16:3398-415. [PMID: 24428801 PMCID: PMC4262008 DOI: 10.1111/1462-2920.12388] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2013] [Revised: 12/30/2013] [Accepted: 01/05/2014] [Indexed: 11/27/2022]
Abstract
Microbial metabolism is the engine that drives global biogeochemical cycles, yet many key transformations are carried out by microbial consortia over short spatiotemporal scales that elude detection by traditional analytical approaches. We investigate syntrophic sulfur cycling in the 'pink berry' consortia of the Sippewissett Salt Marsh through an integrative study at the microbial scale. The pink berries are macroscopic, photosynthetic microbial aggregates composed primarily of two closely associated species: sulfide-oxidizing purple sulfur bacteria (PB-PSB1) and sulfate-reducing bacteria (PB-SRB1). Using metagenomic sequencing and (34) S-enriched sulfate stable isotope probing coupled with nanoSIMS, we demonstrate interspecies transfer of reduced sulfur metabolites from PB-SRB1 to PB-PSB1. The pink berries catalyse net sulfide oxidation and maintain internal sulfide concentrations of 0-500 μm. Sulfide within the berries, captured on silver wires and analysed using secondary ion mass spectrometer, increased in abundance towards the berry interior, while δ(34) S-sulfide decreased from 6‰ to -31‰ from the exterior to interior of the berry. These values correspond to sulfate-sulfide isotopic fractionations (15-53‰) consistent with either sulfate reduction or a mixture of reductive and oxidative metabolisms. Together this combined metagenomic and high-resolution isotopic analysis demonstrates active sulfur cycling at the microscale within well-structured macroscopic consortia consisting of sulfide-oxidizing anoxygenic phototrophs and sulfate-reducing bacteria.
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Affiliation(s)
- Elizabeth G Wilbanks
- Department of Department of Microbiology Graduate Group, University of CaliforniaDavis, CA, 95616, USA
| | - Ulrike Jaekel
- Department of Evolution and Ecology, University of CaliforniaDavis, CA, 95616, USA
- Department of Microbiology and Immunology, University of CaliforniaDavis, CA, 95616, USA
| | - Verena Salman
- Department of Biomedical Engineering, University of CaliforniaDavis, CA, 95616, USA
| | - Parris T Humphrey
- UC Davis Genome Center, University of CaliforniaDavis, CA, 95616, USA
| | - Jonathan A Eisen
- Arctic Technology, Shell Technology NorwayOslo, N-0277, Norway
- Department of Organismic and Evolutionary Biology, Harvard UniversityCambridge, MA, 02138, USA
- Department of Marine Sciences, University of North Carolina at Chapel HillChapel Hill, NC, 27599, USA
| | - Marc T Facciotti
- Department of Marine Sciences, University of North Carolina at Chapel HillChapel Hill, NC, 27599, USA
- Ecology and Evolutionary Biology, University of ArizonaTucson, AZ, 85721, USA
| | - Daniel H Buckley
- Crop and Soil Sciences, Cornell UniversityIthaca, NY, 14853, USA
| | - Stephen H Zinder
- Department of Microbiology, Cornell UniversityIthaca, NY, 14853, USA
| | - Gregory K Druschel
- Department of Earth Sciences, Indiana University-Purdue UniversityIndianapolis, IN, 46202, USA
| | - David A Fike
- Department of Earth and Planetary Sciences, Washington UniversitySt. Louis, MO, 63130, USA
| | - Victoria J Orphan
- Division of Geological and Planetary Sciences, California Institute of TechnologyPasadena, CA, 91125, USA
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Houghton J, Fike D, Druschel G, Orphan V, Hoehler TM, Des Marais DJ. Spatial variability in photosynthetic and heterotrophic activity drives localized δ13C org fluctuations and carbonate precipitation in hypersaline microbial mats. GEOBIOLOGY 2014; 12:557-574. [PMID: 25312537 DOI: 10.1111/gbi.12113] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Accepted: 08/30/2014] [Indexed: 06/04/2023]
Abstract
Modern laminated photosynthetic microbial mats are ideal environments to study how microbial activity creates and modifies carbon and sulfur isotopic signatures prior to lithification. Laminated microbial mats from a hypersaline lagoon (Guerrero Negro, Baja California, Mexico) maintained in a flume in a greenhouse at NASA Ames Research Center were sampled for δ(13) C of organic material and carbonate to assess the impact of carbon fixation (e.g., photosynthesis) and decomposition (e.g., bacterial respiration) on δ(13) C signatures. In the photic zone, the δ(13) C org signature records a complex relationship between the activities of cyanobacteria under variable conditions of CO2 limitation with a significant contribution from green sulfur bacteria using the reductive TCA cycle for carbon fixation. Carbonate is present in some layers of the mat, associated with high concentrations of bacteriochlorophyll e (characteristic of green sulfur bacteria) and exhibits δ(13) C signatures similar to DIC in the overlying water column (-2.0‰), with small but variable decreases consistent with localized heterotrophic activity from sulfate-reducing bacteria (SRB). Model results indicate respiration rates in the upper 12 mm of the mat alter in situ pH and HCO3- concentrations to create both phototrophic CO2 limitation and carbonate supersaturation, leading to local precipitation of carbonate minerals. The measured activity of SRB with depth suggests they variably contribute to decomposition in the mat dependent on organic substrate concentrations. Millimeter-scale variability in the δ(13) C org signature beneath the photic zone in the mat is a result of shifting dominance between cyanobacteria and green sulfur bacteria with the aggregate signature overprinted by heterotrophic reworking by SRB and methanogens. These observations highlight the impact of sedimentary microbial processes on δ(13) C org signatures; these processes need to be considered when attempting to relate observed isotopic signatures in ancient sedimentary strata to conditions in the overlying water column at the time of deposition and associated inferences about carbon cycling.
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Affiliation(s)
- J Houghton
- Department of Earth and Planetary Sciences, Washington University, St. Louis, MO, USA
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Jiang C, Hsu-Kim H. Direct in situ measurement of dissolved zinc in the presence of zinc oxide nanoparticles using anodic stripping voltammetry. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2014; 16:2536-2544. [PMID: 25220562 DOI: 10.1039/c4em00278d] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The wide use of metal-based nanomaterials such as zinc oxide (ZnO) nanoparticles (NPs) has generated concerns regarding their environmental and health risks. For ZnO NPs, their toxicity in aquatic systems often depends on the release of dissolved zinc species, and the rate of dissolution is influenced by water chemistry, including the presence of zinc-chelating ligands. A challenge, however, remains in quantifying the dissolution of ZnO NPs, particularly for time scales that are short enough to determine rates. This paper reports the application of anodic stripping voltammetry (ASV) with a hanging mercury drop electrode to directly measure the concentration of dissolved zinc in ZnO NP suspensions, without separation of the ZnO NPs from the aqueous phase. The effects of the deposition time and the electrochemical potential scan rate on the ASV measurement were consistent with expectations for dissolved phase measurements. The dissolved zinc concentration measured by ASV ([Zn]ASV) was compared with that measured by inductively coupled plasma mass spectrometry (ICP-MS) after ultracentrifugation ([Zn]ICP-MS), for four types of ZnO NPs with different coatings and primary particle diameters. For small ZnO NPs (4-5 nm), [Zn]ASV was 20% higher than [Zn]ICP-MS, suggesting that these small NPs contributed to the voltammetric measurement. For larger ZnO NPs (approximately 20 nm), [Zn]ASV was (79 ± 19)% of [Zn]ICP-MS, despite the high concentrations of ZnO NPs in suspension. Using ASV, the dissolution of ZnO NPs was studied, with or without Suwannee River Fulvic Acid (SRFA). Although SRFA diminished the ASV stripping current, dissolution of 20 nm ZnO NPs was significantly promoted at high fulvic acid to ZnO NP ratios. The ASV method described in this paper provides a useful tool for studying the dissolution kinetics of ZnO NPs in complex environmental matrices.
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Affiliation(s)
- Chuanjia Jiang
- Department of Civil and Environmental Engineering, Duke University, Box 90287, NC 27708, USA.
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MacDonald DJ, Findlay AJ, McAllister SM, Barnett JM, Hredzak-Showalter P, Krepski ST, Cone SG, Scott J, Bennett SK, Chan CS, Emerson D, Luther Iii GW. Using in situ voltammetry as a tool to identify and characterize habitats of iron-oxidizing bacteria: from fresh water wetlands to hydrothermal vent sites. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2014; 16:2117-2126. [PMID: 24924809 DOI: 10.1039/c4em00073k] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Iron-oxidizing bacteria (FeOB) likely play a large role in the biogeochemistry of iron, making the detection and understanding of the biogeochemical processes FeOB are involved in of critical importance. By deploying our in situ voltammetry system, we are able to measure a variety of redox species, specifically Fe(ii) and O2, simultaneously. This technique provides significant advantages in both characterizing the environments in which microaerophilic FeOB are found, and finding diverse conditions in which FeOB could potentially thrive. Described here are four environments with different salinities [one fresh groundwater seep site, one beach-groundwater mixing site, one hydrothermal vent site (Mid-Atlantic Ridge), and one estuary (Chesapeake Bay)] where in situ voltammetry was deployed, and where the presence of FeOB were confirmed by either culturing methods or molecular data. The sites varied in both O2 and Fe(ii) content with O2 ranging from below the 3 μM detection limit of the electrodes at the Chesapeake Bay suboxic zone, to as high 150 μM O2 at the vent site. In addition, a range of Fe(ii) concentrations supported FeOB communities, from 3 μM Fe(ii) in the Chesapeake Bay to 300 μM in the beach aquifer. In situ electrochemistry provides the means to quickly measure these redox gradients at appropriate resolution, making it possible in real time to detect niches likely inhabited by microaerophilic FeOB, then accurately sample for proof of FeOB presence and activity. This study demonstrates the utility of this approach while also greatly expanding our knowledge of FeOB habitats.
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Affiliation(s)
- Daniel J MacDonald
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware, USA.
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Wang C, Shan B, Zhang H, Rong N. Analyzing sediment dissolved oxygen based on microprofile modeling. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2014; 21:10320-10328. [PMID: 24764008 DOI: 10.1007/s11356-014-2875-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2014] [Accepted: 04/02/2014] [Indexed: 06/03/2023]
Abstract
Sediment plays a key role in controlling the oxygen demand of aquatic systems. The reaction rate, penetration depth, and flux across the sediment-water interface (SWI) are important factors in sediment oxygen consumption. However, there were few methods to collect these data until recently. In this study, methods were developed to simulate the oxygen microprofile and calculate the sediment oxygen consumption rate, oxygen penetration depth, and oxygen flux across the SWI. We constructed a sediment oxygen measuring system using an oxygen microelectrode and a control device. The simulation equations were derived from both zero and first-order kinetic models, while the penetration depth and the oxygen flux were calculated from the simulation results. The method was tested on four prepared sediment samples. Decreases in dissolved oxygen in surface sediment were clearly detected by the microelectrode. The modeled data were a good fit for the observed data (R (2) > 0.95), and zero-order kinetics were more suitable than first-order kinetics. The values for penetration depth (1.3-3.9 mm) and oxygen fluxes (0.061-0.114 mg/cm(2)/day) calculated by our methods are comparable with those from other studies.
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Affiliation(s)
- Chao Wang
- State Key Laboratory on Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China
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Gilhooly WP, Fike DA, Druschel GK, Kafantaris FCA, Price RE, Amend JP. Sulfur and oxygen isotope insights into sulfur cycling in shallow-sea hydrothermal vents, Milos, Greece. GEOCHEMICAL TRANSACTIONS 2014; 15:12. [PMID: 25183951 PMCID: PMC4145251 DOI: 10.1186/s12932-014-0012-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Accepted: 07/22/2014] [Indexed: 05/29/2023]
Abstract
Shallow-sea (5 m depth) hydrothermal venting off Milos Island provides an ideal opportunity to target transitions between igneous abiogenic sulfide inputs and biogenic sulfide production during microbial sulfate reduction. Seafloor vent features include large (>1 m(2)) white patches containing hydrothermal minerals (elemental sulfur and orange/yellow patches of arsenic-sulfides) and cells of sulfur oxidizing and reducing microorganisms. Sulfide-sensitive film deployed in the vent and non-vent sediments captured strong geochemical spatial patterns that varied from advective to diffusive sulfide transport from the subsurface. Despite clear visual evidence for the close association of vent organisms and hydrothermalism, the sulfur and oxygen isotope composition of pore fluids did not permit delineation of a biotic signal separate from an abiotic signal. Hydrogen sulfide (H2S) in the free gas had uniform δ(34)S values (2.5 ± 0.28‰, n = 4) that were nearly identical to pore water H2S (2.7 ± 0.36‰, n = 21). In pore water sulfate, there were no paired increases in δ(34)SSO4 and δ(18)OSO4 as expected of microbial sulfate reduction. Instead, pore water δ(34)SSO4 values decreased (from approximately 21‰ to 17‰) as temperature increased (up to 97.4°C) across each hydrothermal feature. We interpret the inverse relationship between temperature and δ(34)SSO4 as a mixing process between oxic seawater and (34)S-depleted hydrothermal inputs that are oxidized during seawater entrainment. An isotope mass balance model suggests secondary sulfate from sulfide oxidation provides at least 15% of the bulk sulfate pool. Coincident with this trend in δ(34)SSO4, the oxygen isotope composition of sulfate tended to be (18)O-enriched in low pH (<5), high temperature (>75°C) pore waters. The shift toward high δ(18)OSO4 is consistent with equilibrium isotope exchange under acidic and high temperature conditions. The source of H2S contained in hydrothermal fluids could not be determined with the present dataset; however, the end-member δ(34)S value of H2S discharged to the seafloor is consistent with equilibrium isotope exchange with subsurface anhydrite veins at a temperature of ~300°C. Any biological sulfur cycling within these hydrothermal systems is masked by abiotic chemical reactions driven by mixing between low-sulfate, H2S-rich hydrothermal fluids and oxic, sulfate-rich seawater.
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Affiliation(s)
- William P Gilhooly
- Department of Earth Sciences, Indiana University-Purdue University Indianapolis, Indianapolis, IN, USA
- Department of Earth and Planetary Sciences, Washington University in St. Louis, St. Louis, MO, USA
| | - David A Fike
- Department of Earth and Planetary Sciences, Washington University in St. Louis, St. Louis, MO, USA
| | - Gregory K Druschel
- Department of Earth Sciences, Indiana University-Purdue University Indianapolis, Indianapolis, IN, USA
| | | | - Roy E Price
- Department of Earth Sciences, University of Southern California, Los Angeles, CA, USA
- SUNY Stony Brook, School of Marine and Atmospheric Sciences, Stony Brook, NY, USA
| | - Jan P Amend
- Department of Earth Sciences, University of Southern California, Los Angeles, CA, USA
- Department of Biological Sciences, University of Southern California, Los Angeles, USA
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47
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Crowe SA, Maresca JA, Jones C, Sturm A, Henny C, Fowle DA, Cox RP, Delong EF, Canfield DE. Deep-water anoxygenic photosythesis in a ferruginous chemocline. GEOBIOLOGY 2014; 12:322-339. [PMID: 24923179 DOI: 10.1111/gbi.12089] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Accepted: 04/08/2014] [Indexed: 06/03/2023]
Abstract
Ferruginous Lake Matano, Indonesia hosts one of the deepest anoxygenic photosynthetic communities on Earth. This community is dominated by low-light adapted, BChl e-synthesizing green sulfur bacteria (GSB), which comprise ~25% of the microbial community immediately below the oxic-anoxic boundary (OAB; 115-120 m in 2010). The size of this community is dependent on the mixing regime within the lake and the depth of the OAB-at ~117 m, the GSB live near their low-light limit. Slow growth and C-fixation rates suggest that the Lake Matano GSB can be supported by sulfide even though it only accumulates to scarcely detectable (low μm to nm) concentrations. A model laboratory strain (Chlorobaculum tepidum) is indeed able to access HS- for oxidation at nm concentrations. Furthermore, the GSB in Lake Matano possess a full complement of S-oxidizing genes. Together, this physiological and genetic information suggests that deep-water GSB can be supported by a S-cycle, even under ferruginous conditions. The constraints we place on the metabolic capacity and physiology of GSB have important geobiological implications. Biomarkers diagnostic of GSB would be a good proxy for anoxic conditions but could not discriminate between euxinic and ferruginous states, and though GSB biomarkers could indicate a substantial GSB community, such a community may exist with very little metabolic activity. The light requirements of GSB indicate that at light levels comparable to those in the OAB of Lake Matano or the Black Sea, GSB would have contributed little to global ocean primary production, nutrient cycling, and banded iron formation (BIF) deposition in the Precambrian. Before the proliferation of oxygenic photosynthesis, shallower OABs and lower light absorption in the ocean's surface waters would have permitted greater light availability to GSB, potentially leading to a greater role for GSB in global biogeochemical cycles.
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Affiliation(s)
- S A Crowe
- Nordic Center for Earth Evolution and Institute of Biology, University of Southern Denmark, Odense, Denmark; Departments of Microbiology & Immunology and Earth, Ocean, & Atmospheric Sciences, University of British Columbia, Vancouver, Canada
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48
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Peijnenburg WJGM, Teasdale PR, Reible D, Mondon J, Bennett WW, Campbell PGC. Passive sampling methods for contaminated sediments: state of the science for metals. INTEGRATED ENVIRONMENTAL ASSESSMENT AND MANAGEMENT 2014; 10:179-96. [PMID: 24470168 PMCID: PMC4238822 DOI: 10.1002/ieam.1502] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Revised: 08/23/2013] [Accepted: 11/01/2013] [Indexed: 05/19/2023]
Abstract
"Dissolved" concentrations of contaminants in sediment porewater (Cfree ) provide a more relevant exposure metric for risk assessment than do total concentrations. Passive sampling methods (PSMs) for estimating Cfree offer the potential for cost-efficient and accurate in situ characterization of Cfree for inorganic sediment contaminants. In contrast to the PSMs validated and applied for organic contaminants, the various passive sampling devices developed for metals, metalloids, and some nonmetals (collectively termed "metals") have been exploited to a limited extent, despite recognized advantages that include low detection limits, detection of time-averaged trends, high spatial resolution, information about dissolved metal speciation, and the ability to capture episodic events and cyclic changes that may be missed by occasional grab sampling. We summarize the PSM approaches for assessing metal toxicity to, and bioaccumulation by, sediment-dwelling biota, including the recognized advantages and limitations of each approach, the need for standardization, and further work needed to facilitate broader acceptance and application of PSM-derived information by decision makers.
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Affiliation(s)
- Willie JGM Peijnenburg
- National Institute for Public Health and the Environment, Center for Safety of Substances and ProductsBilthoven, The Netherlands
| | - Peter R Teasdale
- Environmental Futures Research Institute, School of Environment, Griffith UniversityGold Coast Campus, Southport, Australia
| | - Danny Reible
- Department of Civil and Environmental Engineering, Texas Tech UniversityLubbock, Texas, USA
| | - Julie Mondon
- Center for Integrated Ecology, Environmental Sustainability Research Cluster, Deakin UniversityWarrnambool Campus, Warrnambool, Victoria, Australia
| | - William W Bennett
- Environmental Futures Research Institute, School of Environment, Griffith UniversityGold Coast Campus, Southport, Australia
| | - Peter GC Campbell
- Université du Québec, Institut National de la Recherche Scientifique, Centre Eau, Terre et EnvironnementQuébec, Canada
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49
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Cesbron F, Metzger E, Launeau P, Deflandre B, Delgard ML, Thibault de Chanvalon A, Geslin E, Anschutz P, Jézéquel D. Simultaneous 2D imaging of dissolved iron and reactive phosphorus in sediment porewaters by thin-film and hyperspectral methods. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2014; 48:2816-2826. [PMID: 24502458 DOI: 10.1021/es404724r] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
This study presents a new approach combining diffusive equilibrium in thin-film (DET) and spectrophotometric methods to determine the spatial variability of dissolved iron and dissolved reactive phosphorus (DRP) with a single gel probe. Its originality is (1) to postpone up to three months the colorimetric reaction of DET by freezing and (2) to measure simultaneously dissolved iron and DRP by hyperspectral imaging at a submillimeter resolution. After a few minutes at room temperature, the thawed gel is sandwiched between two monospecific reagent DET gels, leading to magenta and blue coloration for iron and phosphate, respectively. Spatial distribution of the resulting colors is obtained using a hyperspectral camera. Reflectance spectra analysis enables deconvolution of specific colorations by the unmixing method applied to the logarithmic reflectance, leading to an accurate quantification of iron and DRP. This method was applied in the Arcachon lagoon (France) on muddy sediments colonized by eelgrass (Zostera noltei) meadows. The 2D gel probes highlighted microstructures in the spatial distribution of dissolved iron and phosphorus, which are most likely associated with the occurrence of benthic fauna burrows and seagrass roots.
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Affiliation(s)
- Florian Cesbron
- UMR CNRS 6112 LPGN-BIAF-Laboratoire des Bio-Indicateurs Actuels et Fossiles, Université d'Angers , 49045 Angers Cedex, France
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50
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Metzger E, Viollier E, Simonucci C, Prévot F, Langlet D, Jézéquel D. Millimeter-scale alkalinity measurement in marine sediment using DET probes and colorimetric determination. WATER RESEARCH 2013; 47:5575-5583. [PMID: 23870435 DOI: 10.1016/j.watres.2013.06.038] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Revised: 06/14/2013] [Accepted: 06/17/2013] [Indexed: 06/02/2023]
Abstract
Constrained DET (Diffusive Equilibration in Thin films) probes equipped with 75 sampling layers of agarose gel (DGT Research(©)) were used to sample bottom and pore waters in marine sediment with a 2 mm vertical resolution. After retrieval, each piece of hydrogel, corresponding to 25 μL, was introduced into 1 mL of colorimetric reagent (CR) solution consisting of formic acid and bromophenol blue. After the elution/reaction time, absorbance of the latter mixture was read at 590 nm and compared to a calibration curve obtained with the same protocol applied to mini DET probes soaked in sodium hydrogen carbonate standard solutions. This method allows rapid alkalinity determinations for the small volumes of anoxic pore water entrapped into the gel. The method was assessed on organic-rich coastal marine sediments from Thau lagoon (France). Alkalinity values in the overlying waters were in agreement with data obtained by classical sampling techniques. Pore water data showed a progressive increase of alkalinity in the sediment from 2 to 10 mmol kg(-1), corresponding to anaerobic respiration in organic-rich sediments. Moreover, replicates of high-resolution DET profiles showed important lateral heterogeneity at a decimeter scale. This underlines the importance of high-resolution spatial methods for alkalinity profiling in coastal marine systems.
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Affiliation(s)
- E Metzger
- UMR CNRS 6112 LPGN-BIAF, Laboratoire des Bio-Indicateurs Actuels et Fossiles, Université d'Angers, 2 Boulevard Lavoisier, 49045 Angers Cedex, France.
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