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Robinson T, Latta DE, Leddy J, Scherer MM. Redox Potentials of Magnetite Suspensions under Reducing Conditions. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:17454-17461. [PMID: 36394877 PMCID: PMC9730839 DOI: 10.1021/acs.est.2c05196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Predicting the redox behavior of magnetite in reducing soils and sediments is challenging because there is neither agreement among measured potentials nor consensus on which Fe(III) | Fe(II) equilibria are most relevant. Here, we measured open-circuit potentials of stoichiometric magnetite equilibrated over a range of solution conditions. Notably, electron transfer mediators were not necessary to reach equilibrium. For conditions where ferrous hydroxide precipitation was limited, Nernstian behavior was observed with an EH vs pH slope of -179 ± 4 mV and an EH vs Fe(II)aq slope of -54 ± 4 mV. Our estimated EHo of 857 ± 8 mV closely matches a maghemite|aqueous Fe(II) EHo of 855 mV, suggesting that it plays a dominant role in poising the solution potential and that it's theoretical Nernst equation of EH[mV] = 855 - 177 pH - 59 log [Fe2+] may be useful in predicting magnetite redox behavior under these conditions. At higher pH values and without added Fe(II), a distinct shift in potentials was observed, indicating that the dominant Fe(III)|Fe(II) couple(s) poising the potential changed. Our findings, coupled with previous Mössbauer spectroscopy and kinetic data, provide compelling evidence that the maghemite/Fe(II)aq couple accurately predicts the redox behavior of stoichiometric magnetite suspensions in the presence of aqueous Fe(II) between pH values of 6.5 and 8.5.
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Affiliation(s)
- Thomas
C. Robinson
- Department
of Civil and Environmental Engineering, University of Iowa, Iowa City, Iowa52242, United States
| | - Drew E. Latta
- Department
of Civil and Environmental Engineering, University of Iowa, Iowa City, Iowa52242, United States
| | - Johna Leddy
- Department
of Chemistry, University of Iowa, Iowa City, Iowa52242, United States
| | - Michelle M. Scherer
- Department
of Civil and Environmental Engineering, University of Iowa, Iowa City, Iowa52242, United States
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2
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Electromagnetic Properties Monitoring to Detect Different Biodegradation Kinetics in Hydrocarbon-Contaminated Soil. SOIL SYSTEMS 2022. [DOI: 10.3390/soilsystems6020048] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The electromagnetic properties (electrical permittivity and electrical conductivity) of three different soil mesocosms polluted with diesel oil were monitored using a time-domain reflectometry probe for 8 months. The main target of the research was to establish a relationship between the development of biological activity within the mesocosms and the temporal behaviour of electromagnetic properties. The trend of the electromagnetic properties exhibited different responses that could be related to the composition of the mesocosms and their variation with time during the runs. We considered three different mesocosms with similar soil conditions and the same diesel oil concentration: porosity of 45%, volumetric diesel oil content of 9%, and volumetric water content of 15%. The first one was subjected to a natural attenuation (NA), the second one was biostimulated without inoculation (BS), and the third one was biostimulated with inoculation (BS + IN). The biostimulated mesocosms showed a marked decrease in electrical permittivity and electrical conductivity, whereas the naturally attenuated mesocosm did not show these variations. Between the biostimulated mesocosms, the inoculated one showed the fastest variations in the electromagnetic properties. The microbial activity and the pollutant degradation were evidenced by the analyses performed at the end of the experiment. As demonstrated by the results for the fluorescein diacetate analysis, the microbial activity was a bit higher for the inoculated microcosm, which also showed faster variations of the electromagnetic properties. In the biostimulated mesocosms, the removal of diesel oil was 66% and 72%, respectively. With natural attenuation, there was a limited removal efficiency, in the order of 2%. Even if the electromagnetic properties evidenced different kinetics of bioremediation in BS and BS + IN, both were able to successfully degrade similar percentages of the contaminant after 8 months. The long monitoring revealed that a substantial decrease in the electromagnetic properties happened only in the first month after contamination. Additionally, an increasing trend of the permittivity was detected in the following months, before reaching a steady-state condition. This study revealed that biodegradation processes with acceptable overall removal efficiency can be monitored successfully by observing the variations in the electromagnetic properties.
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3
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Gradient Self-Potential Logging in the Rio Grande to Identify Gaining and Losing Reaches across the Mesilla Valley. WATER 2021. [DOI: 10.3390/w13101331] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The Rio Grande/Río Bravo del Norte (hereinafter referred to as the “Rio Grande”) is the primary source of recharge to the Mesilla Basin/Conejos-Médanos aquifer system in the Mesilla Valley of New Mexico and Texas. The Mesilla Basin aquifer system is the U.S. part of the Mesilla Basin/Conejos-Médanos aquifer system and is the primary source of water supply to several communities along the United States–Mexico border in and near the Mesilla Valley. Identifying the gaining and losing reaches of the Rio Grande in the Mesilla Valley is therefore critical for managing the quality and quantity of surface and groundwater resources available to stakeholders in the Mesilla Valley and downstream. A gradient self-potential (SP) logging survey was completed in the Rio Grande across the Mesilla Valley between 26 June and 2 July 2020, to identify reaches where surface-water gains and losses were occurring by interpreting an estimate of the streaming-potential component of the electrostatic field in the river, measured during bankfull flow. The survey, completed as part of the Transboundary Aquifer Assessment Program, began at Leasburg Dam in New Mexico near the northern terminus of the Mesilla Valley and ended ~72 kilometers (km) downstream at Canutillo, Texas. Electric potential data indicated a net losing condition for ~32 km between the Leasburg Dam and Mesilla Diversion Dam in New Mexico, with one ~200-m long reach showing an isolated saline-groundwater gaining condition. Downstream from the Mesilla Diversion Dam, electric-potential data indicated a neutral-to-mild gaining condition for 12 km that transitioned to a mild-to-moderate gaining condition between 12 and ~22 km downstream from the dam, before transitioning back to a losing condition along the remaining 18 km of the survey reach. The interpreted gaining and losing reaches are substantiated by potentiometric surface mapping completed in hydrostratigraphic units of the Mesilla Basin aquifer system between 2010 and 2011, and corroborated by surface-water temperature and conductivity logging and relative median streamflow gains and losses, quantified from streamflow measurements made annually at 16 seepage-measurement stations along the survey reach between 1988 and 1998 and between 2004 and 2013. The gaining and losing reaches of the Rio Grande in the Mesilla Valley, interpreted from electric potential data, compare well with relative median streamflow gains and losses along the 72-km long survey reach.
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4
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Mapping the Pollution Plume Using the Self-Potential Geophysical Method: Case of Oum Azza Landfill, Rabat, Morocco. WATER 2021. [DOI: 10.3390/w13070961] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The main landfill in the city of Rabat (Morocco) is based on sandy material containing the shallow Mio-Pliocene aquifer. The presence of a pollution plume is likely, but its extent is not known. Measurements of spontaneous potential (SP) from the soil surface were cross-referenced with direct measurements of the water table and leachates (pH, redox potential, electrical conductivity) according to the available accesses, as well as with an analysis of the landscape and the water table flows. With a few precautions during data acquisition on this resistive terrain, the results made it possible to separate the electrokinetic (~30%) and electrochemical (~70%) components responsible for the range of potentials observed (70 mV). The plume is detected in the hydrogeological downstream of the discharge, but is captured by the natural drainage network and does not extend further under the hills.
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5
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Sun Y, Liu Y, Pan J, Wang F, Li M. Perspectives on Cultivation Strategies of Archaea. MICROBIAL ECOLOGY 2020; 79:770-784. [PMID: 31432245 DOI: 10.1007/s00248-019-01422-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Accepted: 08/01/2019] [Indexed: 06/10/2023]
Abstract
Archaea have been recognized as a major domain of life since the 1970s and occupy a key position in the tree of life. Recent advances in culture-independent approaches have greatly accelerated the research son Archaea. However, many hypotheses concerning the diversity, physiology, and evolution of archaea are waiting to be confirmed by culture-base experiments. Consequently, archaeal isolates are in great demand. On the other hand, traditional approaches of archaeal cultivation are rarely successful and require urgent improvement. Here, we review the current practices and applicable microbial cultivation techniques, to inform on potential strategies that could improve archaeal cultivation in the future. We first summarize the current knowledge on archaeal diversity, with an emphasis on cultivated and uncultivated lineages pertinent to future research. Possible causes for the low success rate of the current cultivation practices are then discussed to propose future improvements. Finally, innovative insights for archaeal cultivation are described, including (1) medium refinement for selective cultivation based on the genetic and transcriptional information; (2) consideration of the up-to-date archaeal culturing skills; and (3) application of multiple cultivation techniques, such as co-culture, direct interspecies electron transfer (DIET), single-cell isolation, high-throughput culturing (HTC), and simulation of the natural habitat. Improved cultivation efforts should allow successful isolation of as yet uncultured archaea, contributing to the much-needed physiological investigation of archaea.
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Affiliation(s)
- Yihua Sun
- Institute for Advanced Study, Shenzhen University, Shenzhen, Guangdong, People's Republic of China
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen, Guangdong, People's Republic of China
| | - Yang Liu
- Institute for Advanced Study, Shenzhen University, Shenzhen, Guangdong, People's Republic of China
| | - Jie Pan
- Institute for Advanced Study, Shenzhen University, Shenzhen, Guangdong, People's Republic of China
| | - Fengping Wang
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, People's Republic of China
- State Key Laboratory of Ocean Engineering, Shanghai Jiao Tong University, Shanghai, People's Republic of China
| | - Meng Li
- Institute for Advanced Study, Shenzhen University, Shenzhen, Guangdong, People's Republic of China.
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6
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Time-Domain Reflectometry (TDR) Monitoring at a Lab Scale of Aerobic Biological Processes in a Soil Contaminated by Diesel Oil. APPLIED SCIENCES-BASEL 2019. [DOI: 10.3390/app9245487] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
This study aims to monitor the biological processes ongoing in a hydrocarbon polluted soil. The experiments were carried out at a laboratory scale by measuring the evolution of its geophysical electromagnetic parameters. Time-domain reflectometry (TDR) probes were used to measure dielectric permittivity and electrical conductivity in columns of sandy soil artificially contaminated with diesel oil (Voil/Vtot = 0.19). To provide aerobic conditions suitable for the growth of microorganisms, they were hydrated with Mineral Salt Medium for Bacteria. One mesocosm was aerated by injecting air from the bottom of the column, while the other had only natural aeration due to diffusion of air through the soil itself. The monitoring lasted 105 days. Geophysical measurements were supported by microbiological, gas chromatographic analyses, and scanning electron microscope (SEM) images. Air injection heavily influenced the TDR monitoring, probably due to the generation of air bubbles around the probe that interfered with the probe–soil coupling. Therefore, the measurement accuracy of geophysical properties was dramatically reduced in the aerated system, although biological analyses showed that aeration strongly supports microbial activity. In the non-aerated system, a slight (2%) linear decrease of dielectric permittivity was observed over time. Meanwhile, the electrical conductivity initially decreased, then increased from day 20 to day 45, then decreased again by about 30%. We compared these results with other researches in recent literature to explain the complex biological phenomena that can induce variations in electrical parameters in a contaminated soil matrix, from salt depletion to pore clogging.
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7
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Fernandez PM, Bloem E, Binley A, Philippe RSBA, French HK. Monitoring redox sensitive conditions at the groundwater interface using electrical resistivity and self-potential. JOURNAL OF CONTAMINANT HYDROLOGY 2019; 226:103517. [PMID: 31280034 DOI: 10.1016/j.jconhyd.2019.103517] [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: 05/29/2018] [Revised: 05/23/2019] [Accepted: 06/20/2019] [Indexed: 06/09/2023]
Abstract
Assessing redox conditions in soil and groundwater is challenging because redox reactions are oxygen sensitive, hence, destructive sampling methods may provide contact with air and influence the redox state. Furthermore, commonly used redox potential sensors provide only point measurements and are prone to error. This paper assesses whether combining electrical resistivity (ER) and self-potential (SP) measurements can allow the mapping of zones affected by anaerobic degradation. We use ER imaging because anaerobic degradation can release iron and manganese ions, which decreases pore water resistivity, and produces gas, which increases resistivity. Also, electrochemical differences between anaerobic and aerobic zones may create an electron flow, forming a self-potential anomaly. In this laboratory study, with four sand tanks with constant water table heights, time-lapse ER and SP mapped changes in electrical/electron flow properties due to organic contaminant (propylene glycol) degradation. Sampled pore water mapped degradation and water chemistry. When iron and manganese oxides were available, degradation reduced resistivity, because of cation release in pore water. When iron and manganese oxides were unavailable, resistivity increased, plausibly from methane production, which reduced water saturation. To bypass the reactions producing methane and release of metallic cations, a metal pipe was installed in the sand tanks between anaerobic and aerobic zones. The degradation creates an electron surplus at the anaerobic degradation site. The metal pipe allowed electron flow from the anaerobic degradation site to the oxygen-rich near surface. The electrical current sent through the metal pipe formed an SP anomaly observable on the surface of the sand tank. Time-lapse ER demonstrates potential for mapping degradation zones under anaerobic conditions. When an electrical conductor bridges the anaerobic zone with the near surface, the electron flow causes an SP anomaly on the surface. However, electrochemical differences between anaerobic and aerobic zones alone produced no SP signal. Despite their limitations, ER and SP are promising tools for monitoring redox sensitive conditions in unsaturated sandy soils but should not be used in isolation.
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Affiliation(s)
- Perrine M Fernandez
- Norwegian University of Life Sciences (NMBU), Universitetstunet 3, 1430 Ås, Norway.
| | - Esther Bloem
- Norwegian Institute of Bioeconomy Research (NIBIO), Høgskoleveien 7, 1430 Ås, Norway.
| | - Andrew Binley
- Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, United Kingdom.
| | | | - Helen K French
- Norwegian University of Life Sciences (NMBU), Universitetstunet 3, 1430 Ås, Norway; Norwegian Institute of Bioeconomy Research (NIBIO), Høgskoleveien 7, 1430 Ås, Norway.
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8
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Bioelectrochemical Systems for Groundwater Remediation: The Development Trend and Research Front Revealed by Bibliometric Analysis. WATER 2019. [DOI: 10.3390/w11081532] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
: Due to the deficiency of fresh water resources and the deterioration of groundwater quality worldwide, groundwater remedial technologies are especially crucial for preventing groundwater pollution and protecting the precious groundwater resource. Among the remedial alternatives, bioelectrochemical systems have unique advantages on both economic and technological aspects. However, it is rare to see a deep study focused on the information mining and visualization of the publications in this field, and research that can reveal and visualize the development trajectory and trends is scarce. Therefore, this study summarizes the published information in this field from the Web of Science Core Collection of the last two decades (1999–2018) and uses Citespace to quantitatively visualize the relationship of authors, published countries, organizations, funding sources, and journals and detect the research front by analyzing keywords and burst terms. The results indicate that the studies focused on bioelectrochemical systems for groundwater remediation have had a significant increase during the last two decades, especially in China, Germany and Italy. The national research institutes and universities of the USA and the countries mentioned above dominate the research. Environmental Science & Technology, Applied and Environmental Microbiology, and Water Research are the most published journals in this field. The network maps of the keywords and burst terms suggest that reductive microbial diversity, electron transfer, microbial fuel cell, etc., are the research hotspots in recent years, and studies focused on microbial enrichment culture, energy supply/recovery, combined pollution remediation, etc., should be enhanced in future.
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9
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Tang J, Li X, Zhao W, Wang Y, Cui P, Zeng RJ, Yu L, Zhou S. Electric field induces electron flow to simultaneously enhance the maturity of aerobic composting and mitigate greenhouse gas emissions. BIORESOURCE TECHNOLOGY 2019; 279:234-242. [PMID: 30735933 DOI: 10.1016/j.biortech.2019.01.140] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/25/2018] [Revised: 01/27/2019] [Accepted: 01/29/2019] [Indexed: 06/09/2023]
Abstract
The long maturation period and greenhouse gas (GHG) emission are two major problems that arise during aerobic composting, mainly due to the low efficiency of O2 transmission and utilization. In this study, a novel electric-field-assisted aerobic composting (EAC) process was tested by simply applying a direct-current voltage of 2 V to a conventional aerobic composting (CAC) process. Compared with the CAC process, the maturation time and the total GHG for the EAC process were reduced by 33% and 70%, respectively. Furthermore, the analyses of O2 consumption and microbial communities demonstrated that the electric field had enhanced O2 utilization by 30 ± 9% and increased the relative abundance of electroactive bacteria by about 3.4-fold compared to CAC. This work has represented a proof of principle for EAC and suggests that the electric field is an effective and environmentally friendly strategy for enhancing compost maturity and mitigating GHG emissions during aerobic composting.
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Affiliation(s)
- Jiahuan Tang
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Xiang Li
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Wenqi Zhao
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Yajun Wang
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Peng Cui
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Raymond Jianxiong Zeng
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Linpeng Yu
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Shungui Zhou
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
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10
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Hunting ER, Harrison RG, Bruder A, van Bodegom PM, van der Geest HG, Kampfraath AA, Vorenhout M, Admiraal W, Cusell C, Gessner MO. Atmospheric Electricity Influencing Biogeochemical Processes in Soils and Sediments. Front Physiol 2019; 10:378. [PMID: 31040789 PMCID: PMC6477044 DOI: 10.3389/fphys.2019.00378] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Accepted: 03/19/2019] [Indexed: 11/16/2022] Open
Abstract
The Earth’s subsurface represents a complex electrochemical environment that contains many electro-active chemical compounds that are relevant for a wide array of biologically driven ecosystem processes. Concentrations of many of these electro-active compounds within Earth’s subsurface environments fluctuate during the day and over seasons. This has been observed for surface waters, sediments and continental soils. This variability can affect particularly small, relatively immobile organisms living in these environments. While various drivers have been identified, a comprehensive understanding of the causes and consequences of spatio-temporal variability in subsurface electrochemistry is still lacking. Here we propose that variations in atmospheric electricity (AE) can influence the electrochemical environments of soils, water bodies and their sediments, with implications that are likely relevant for a wide range of organisms and ecosystem processes. We tested this hypothesis in field and laboratory case studies. Based on measurements of subsurface redox conditions in soils and sediment, we found evidence for both local and global variation in AE with corresponding patterns in subsurface redox conditions. In the laboratory, bacterial respiratory responses, electron transport activity and H2S production were observed to be causally linked to changes in atmospheric cation concentrations. We argue that such patterns are part of an overlooked phenomenon. This recognition widens our conceptual understanding of chemical and biological processes in the Earth’s subsurface and their interactions with the atmosphere and the physical environment.
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Affiliation(s)
- Ellard R Hunting
- School of Biological Sciences, University of Bristol, Bristol, United Kingdom.,Biology Department, Woods Hole Oceanographic Institution, Woods Hole, MA, United States.,Institute of Environmental Sciences, Leiden University, Leiden, Netherlands
| | - R Giles Harrison
- Department of Meteorology, University of Reading, Reading, United Kingdom
| | - Andreas Bruder
- Laboratory of Applied Microbiology, University of Applied Sciences and Arts of Southern Switzerland, Bellinzona, Switzerland
| | | | - Harm G van der Geest
- Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, Netherlands
| | - Andries A Kampfraath
- Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, Netherlands
| | | | - Wim Admiraal
- Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, Netherlands
| | - Casper Cusell
- Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, Netherlands
| | - Mark O Gessner
- Department of Experimental Limnology, Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Stechlin, Germany.,Department of Ecology, Berlin Institute of Technology, Berlin, Germany
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11
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Kirmizakis P, Doherty R, Mendonça CA, Costeira R, Allen CCR, Ofterdinger US, Kulakov L. Enhancement of gasworks groundwater remediation by coupling a bio-electrochemical and activated carbon system. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2019; 26:9981-9991. [PMID: 30739291 PMCID: PMC6469603 DOI: 10.1007/s11356-019-04297-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Accepted: 01/18/2019] [Indexed: 05/03/2023]
Abstract
Here, we show the electrical response, bacterial community, and remediation of hydrocarbon-contaminated groundwater from a gasworks site using a graphite-chambered bio-electrochemical system (BES) that utilizes granular activated carbon (GAC) as both sorption agent and high surface area anode. Our innovative concept is the design of a graphite electrode chamber system rather than a classic non-conductive BES chamber coupled with GAC as part of the BES. The GAC BES is a good candidate as a sustainable remediation technology that provides improved degradation over GAC, and near real-time observation of associated electrical output. The BES chambers were effectively colonized by the bacterial communities from the contaminated groundwater. Principal coordinate analysis (PCoA) of UniFrac Observed Taxonomic Units shows distinct grouping of microbial types that are associated with the presence of GAC, and grouping of microbial types associated with electroactivity. Bacterial community analysis showed that β-proteobacteria (particularly the PAH-degrading Pseudomonadaceae) dominate all the samples. Rhodocyclaceae- and Comamonadaceae-related OTU were observed to increase in BES cells. The GAC BES (99% removal) outperformed the control graphite GAC chamber, as well as a graphite BES and a control chamber both filled with glass beads.
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Affiliation(s)
- Panagiotis Kirmizakis
- School of the Natural and Built Environment, Queen's University Belfast, Stranmillis Road, Belfast, BT9 5AG, UK
| | - Rory Doherty
- School of the Natural and Built Environment, Queen's University Belfast, Stranmillis Road, Belfast, BT9 5AG, UK.
| | - Carlos A Mendonça
- Department of Geophysics, University of São Paulo, Rua do Matão, São Paulo, 1226, Brazil
| | - Ricardo Costeira
- School of Biological Sciences, Queen's University Belfast, Lisburn Road, Belfast, BT9 7BL, UK
| | - Chris C R Allen
- School of Biological Sciences, Queen's University Belfast, Lisburn Road, Belfast, BT9 7BL, UK
- Institute for Global Food Security, Queen's University Belfast, Lisburn Road, Belfast, BT9 7BL, UK
| | - Ulrich S Ofterdinger
- School of the Natural and Built Environment, Queen's University Belfast, Stranmillis Road, Belfast, BT9 5AG, UK
| | - Leonid Kulakov
- School of Biological Sciences, Queen's University Belfast, Lisburn Road, Belfast, BT9 7BL, UK
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12
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Murugan M, Miran W, Masuda T, Lee DS, Okamoto A. Biosynthesized Iron Sulfide Nanocluster Enhanced Anodic Current Generation by Sulfate Reducing Bacteria in Microbial Fuel Cells. ChemElectroChem 2018. [DOI: 10.1002/celc.201801086] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Muralidharan Murugan
- Global Research Center for Environment and Energy based on Nanomaterials Science (GREEN)National Institute for Materials Science (NIMS) 1-1 Namiki, Tsukuba Ibaraki 305-0044 Japan
- Graduate School of Chemical Sciences and EngineeringHokkaido University Sapporo 060-8628 Japan
| | - Waheed Miran
- Department of Environmental EngineeringKyungpook National University 80 Daehak-ro, Buk-gu Daegu 41566 Republic of Korea
- International Center for Materials Nanoarchitectonics (WPI-MANA)National Institute for Materials Science (NIMS), Namiki, Tsukuba Ibaraki 305-0044 Japan
| | - Takuya Masuda
- Global Research Center for Environment and Energy based on Nanomaterials Science (GREEN)National Institute for Materials Science (NIMS) 1-1 Namiki, Tsukuba Ibaraki 305-0044 Japan
| | - Dae S. Lee
- Department of Environmental EngineeringKyungpook National University 80 Daehak-ro, Buk-gu Daegu 41566 Republic of Korea
| | - Akihiro Okamoto
- International Center for Materials Nanoarchitectonics (WPI-MANA)National Institute for Materials Science (NIMS), Namiki, Tsukuba Ibaraki 305-0044 Japan
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13
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Otte JM, Harter J, Laufer K, Blackwell N, Straub D, Kappler A, Kleindienst S. The distribution of active iron‐cycling bacteria in marine and freshwater sediments is decoupled from geochemical gradients. Environ Microbiol 2018; 20:2483-2499. [DOI: 10.1111/1462-2920.14260] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Revised: 04/26/2018] [Accepted: 04/26/2018] [Indexed: 11/30/2022]
Affiliation(s)
- Julia M. Otte
- Geomicrobiology, Center for Applied Geosciences, University of Tübingen Germany
| | - Johannes Harter
- Geomicrobiology, Center for Applied Geosciences, University of Tübingen Germany
| | - Katja Laufer
- Geomicrobiology, Center for Applied Geosciences, University of Tübingen Germany
- Center for Geomicrobiology, Department of BioscienceAarhus University Denmark
| | - Nia Blackwell
- Microbial Ecology, Center for Applied GeosciencesUniversity of Tübingen Germany
| | - Daniel Straub
- Microbial Ecology, Center for Applied GeosciencesUniversity of Tübingen Germany
| | - Andreas Kappler
- Geomicrobiology, Center for Applied Geosciences, University of Tübingen Germany
- Center for Geomicrobiology, Department of BioscienceAarhus University Denmark
| | - Sara Kleindienst
- Microbial Ecology, Center for Applied GeosciencesUniversity of Tübingen Germany
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14
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Chin KB, Chi I, Pasalic J, Huang CK, Barge LM. An introductory study using impedance spectroscopy technique with polarizable microelectrode for amino acids characterization. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2018; 89:045108. [PMID: 29716330 DOI: 10.1063/1.5020076] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Portable, low power, yet ultra-sensitive life detection instrumentations are vital to future astrobiology flight programs at NASA. In this study, initial attempts to characterize amino acids in an aqueous environment by electrochemical impedance spectroscopy (EIS) using polarizable (blocking) electrodes in order to establish a means of detection via their electrical properties. Seven amino acids were chosen due to their scientific importance in demonstrating sensitivity levels in the range of part per billion concentration. Albeit more challenging in real systems of analyst mixtures, we found individual amino acids in aqueous environment do exhibit some degree of chemical and physical uniqueness to warrant characterization by EIS. The polar amino acids (Asp, Glu, and His) exhibited higher electrochemical activity than the non-polar amino acids (Ala, Gly, Val, and Leu). The non-polar amino acids (Gly and Ala) also exhibited unique electrical properties which appeared to be more dependent on physical characteristics such as molecular weight and structure. At concentrations above 1 mM where the amino acids play a more dominant transport role within the water, the conductivity was found to be more sensitive to concentrations. At lower concentrations <1 mM, however, the polar amino acid solution conductivity remained constant, suggesting poor chemical activity with water. As revealed by equivalent circuit modeling, the relaxation times showed a 1-2 order of magnitude difference between polar and non-polar amino acids. The pseudo-capacitance from EIS measurements on sample mixtures containing salt water and individual amino acids revealed the possibility for improvement in amino acid selectivity using gold nanoporous surface enhanced electrodes. This work establishes important methodologies for characterizing amino acids using EIS combined with microscale electrodes, supporting the case for instrumentation development for life detection and origin of life programs.
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Affiliation(s)
- K B Chin
- NASA Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109, USA
| | - I Chi
- NASA Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109, USA
| | - J Pasalic
- NASA Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109, USA
| | - C-K Huang
- NASA Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109, USA
| | - Laura M Barge
- NASA Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109, USA
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15
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Kawada Y, Kasaya T. Marine self-potential survey for exploring seafloor hydrothermal ore deposits. Sci Rep 2017; 7:13552. [PMID: 29051572 PMCID: PMC5648760 DOI: 10.1038/s41598-017-13920-0] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Accepted: 10/02/2017] [Indexed: 11/09/2022] Open
Abstract
We conducted a self-potential survey at an active hydrothermal field, the Izena hole in the mid-Okinawa Trough, southern Japan. This field is known to contain Kuroko-type massive sulphide deposits. This survey measured the self-potential continuously in ambient seawater using a deep-tow array, which comprises an electrode array with a 30-m-long elastic rod and a stand-alone data acquisition unit. We observed negative self-potential signals not only above active hydrothermal vents and visible sulphide mounds but also above the flat seafloor without such structures. Some signals were detectable >50 m above the seafloor. Analysis of the acquired data revealed these signals’ source as below the seafloor, which suggests that the self-potential method can detect hydrothermal ore deposits effectively. The self-potential survey, an easily performed method for initial surveys, can identify individual sulphide deposits from a vast hydrothermal area.
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Affiliation(s)
- Yoshifumi Kawada
- Project Team for Development of New-generation Research Protocol for Submarine Resources, Japan Agency for Marine-Earth Science and Technology, 2-15 Natsushima-cho, Yokosuka, 237-0061, Japan. .,International Research Institute of Disaster Science, Tohoku University, 468-1 Aoba, Aoba-ku, Sendai, 980-0845, Japan.
| | - Takafumi Kasaya
- Project Team for Development of New-generation Research Protocol for Submarine Resources, Japan Agency for Marine-Earth Science and Technology, 2-15 Natsushima-cho, Yokosuka, 237-0061, Japan.,Research and Development Center for Earthquake and Tsunami, Japan Agency for Marine-Earth Science and Technology, 2-15 Natsushima-cho, Yokosuka, 237-0061, Japan
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16
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Taran O. Electron Transfer between Electrically Conductive Minerals and Quinones. Front Chem 2017; 5:49. [PMID: 28752088 PMCID: PMC5508016 DOI: 10.3389/fchem.2017.00049] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Accepted: 06/21/2017] [Indexed: 01/04/2023] Open
Abstract
Long-distance electron transfer in marine environments couples physically separated redox half-reactions, impacting biogeochemical cycles of iron, sulfur and carbon. Bacterial bio-electrochemical systems that facilitate electron transfer via conductive filaments or across man-made electrodes are well-known, but the impact of abiotic currents across naturally occurring conductive and semiconductive minerals is poorly understood. In this paper I use cyclic voltammetry to explore electron transfer between electrodes made of common iron minerals (magnetite, hematite, pyrite, pyrrhotite, mackinawite, and greigite), and hydroquinones—a class of organic molecules found in carbon-rich sediments. Of all tested minerals, only pyrite and magnetite showed an increase in electric current in the presence of organic molecules, with pyrite showing excellent electrocatalytic performance. Pyrite electrodes performed better than commercially available glassy carbon electrodes and showed higher peak currents, lower overpotential values and a smaller separation between oxidation and reduction peaks for each tested quinone. Hydroquinone oxidation on pyrite surfaces was reversible, diffusion controlled, and stable over a large number of potential cycles. Given the ubiquity of both pyrite and quinones, abiotic electron transfer between minerals and organic molecules is likely widespread in Nature and may contribute to several different phenomena, including anaerobic respiration of a wide variety of microorganisms in temporally anoxic zones or in the proximity of hydrothermal vent chimneys, as well as quinone cycling and the propagation of anoxic zones in organic rich waters. Finally, interactions between pyrite and quinones make use of electrochemical gradients that have been suggested as an important source of energy for the origins of life on Earth. Ubiquinones and iron sulfide clusters are common redox cofactors found in electron transport chains across all domains of life and interactions between quinones and pyrite might have been an early analog of these ubiquitous systems.
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Affiliation(s)
- Olga Taran
- Department of Chemistry, Emory UniversityAtlanta, GA, United States
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17
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Long-distance electron transfer by cable bacteria in aquifer sediments. ISME JOURNAL 2016; 10:2010-9. [PMID: 27058505 PMCID: PMC4939269 DOI: 10.1038/ismej.2015.250] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Revised: 11/19/2015] [Accepted: 11/25/2015] [Indexed: 11/23/2022]
Abstract
The biodegradation of organic pollutants in aquifers is often restricted to the fringes of contaminant plumes where steep countergradients of electron donors and acceptors are separated by limited dispersive mixing. However, long-distance electron transfer (LDET) by filamentous ‘cable bacteria' has recently been discovered in marine sediments to couple spatially separated redox half reactions over centimeter scales. Here we provide primary evidence that such sulfur-oxidizing cable bacteria can also be found at oxic–anoxic interfaces in aquifer sediments, where they provide a means for the direct recycling of sulfate by electron transfer over 1–2-cm distance. Sediments were taken from a hydrocarbon-contaminated aquifer, amended with iron sulfide and saturated with water, leaving the sediment surface exposed to air. Steep geochemical gradients developed in the upper 3 cm, showing a spatial separation of oxygen and sulfide by 9 mm together with a pH profile characteristic for sulfur oxidation by LDET. Bacterial filaments, which were highly abundant in the suboxic zone, were identified by sequencing of 16S rRNA genes and fluorescence in situ hybridization (FISH) as cable bacteria belonging to the Desulfobulbaceae. The detection of similar Desulfobulbaceae at the oxic–anoxic interface of fresh sediment cores taken at a contaminated aquifer suggests that LDET may indeed be active at the capillary fringe in situ.
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Kondo K, Okamoto A, Hashimoto K, Nakamura R. Sulfur-Mediated Electron Shuttling Sustains Microbial Long-Distance Extracellular Electron Transfer with the Aid of Metallic Iron Sulfides. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:7427-7434. [PMID: 26070345 DOI: 10.1021/acs.langmuir.5b01033] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
In addition to serving as an energy source for microbial growth, iron sulfides are proposed to act as naturally occurring electrical wires that mediate long-distance extracellular electron transfer (EET) and bridge spatially discrete redox environments. These hypothetical EET reactions stand on the abilities of microbes to use the interfacial electrochemistry of metallic/semiconductive iron sulfides to maintain metabolisms; however, the mechanisms of these phenomena remain unexplored. To obtain insight into EET to iron sulfides, we monitored EET at the interface between Shewanella oneidensis MR-1 cells and biomineralized iron sulfides in an electrochemical cell. Respiratory current steeply increased with the concomitant formation of poorly crystalline mackinawite (FeS) minerals, indicating that S. oneidensis has the ability to exploit extracellularly formed metallic FeS for long-distance EET. Deletion of major proteins of the metal-reduction (Mtr) pathway (OmcA, MtrC, CymA, and PilD) caused only subtle effects on the EET efficiency, a finding that sharply contrasts the majority of studies that report that the Mtr pathway is indispensable for the reduction of metal oxides and electrodes. The gene expression analyses of polysulfide and thiosulfate reductase suggest the existence of a sulfur-mediated electron-shuttling mechanism by which HS(-) ions and water-soluble polysulfides (HS(n)(-), where n ≥ 2) generated in the periplasmic space deliver electrons from cellular metabolic processes to cell surface-associated FeS. The finding of this Mtr-independent pathway indicates that polysulfide reductases complement the function of outer-membrane cytochromes in EET reactions and, thus, significantly expand the number of microbial species potentially capable of long-distance EET in sulfur-rich anoxic environments.
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Affiliation(s)
- Katsuhito Kondo
- †Department of Applied Chemistry, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Akihiro Okamoto
- †Department of Applied Chemistry, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Kazuhito Hashimoto
- †Department of Applied Chemistry, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Ryuhei Nakamura
- ‡Biofunctional Catalyst Research Team, RIKEN Center for Sustainable Resource Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
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Cable Bacteria in Freshwater Sediments. Appl Environ Microbiol 2015; 81:6003-11. [PMID: 26116678 PMCID: PMC4551263 DOI: 10.1128/aem.01064-15] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Accepted: 06/19/2015] [Indexed: 11/20/2022] Open
Abstract
In marine sediments cathodic oxygen reduction at the sediment surface can be coupled to anodic sulfide oxidation in deeper anoxic layers through electrical currents mediated by filamentous, multicellular bacteria of the Desulfobulbaceae family, the so-called cable bacteria. Until now, cable bacteria have only been reported from marine environments. In this study, we demonstrate that cable bacteria also occur in freshwater sediments. In a first step, homogenized sediment collected from the freshwater stream Giber Å, Denmark, was incubated in the laboratory. After 2 weeks, pH signatures and electric fields indicated electron transfer between vertically separated anodic and cathodic half-reactions. Fluorescence in situ hybridization revealed the presence of Desulfobulbaceae filaments. In addition, in situ measurements of oxygen, pH, and electric potential distributions in the waterlogged banks of Giber Å demonstrated the presence of distant electric redox coupling in naturally occurring freshwater sediment. At the same site, filamentous Desulfobulbaceae with cable bacterium morphology were found to be present. Their 16S rRNA gene sequence placed them as a distinct sister group to the known marine cable bacteria, with the genus Desulfobulbus as the closest cultured lineage. The results of the present study indicate that electric currents mediated by cable bacteria could be important for the biogeochemistry in many more environments than anticipated thus far and suggest a common evolutionary origin of the cable phenotype within Desulfobulbaceae with subsequent diversification into a freshwater and a marine lineage.
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20
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Binley A, Hubbard SS, Huisman JA, Revil A, Robinson DA, Singha K, Slater LD. The emergence of hydrogeophysics for improved understanding of subsurface processes over multiple scales. WATER RESOURCES RESEARCH 2015; 51:3837-3866. [PMID: 26900183 PMCID: PMC4744786 DOI: 10.1002/2015wr017016] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Accepted: 05/09/2015] [Indexed: 05/24/2023]
Abstract
A review of the emergence and development of hydrogeophysicsOutline of emerging techniques in hydrogeophysicsPresentation of future opportunities in hydrogeophysics.
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Affiliation(s)
- Andrew Binley
- Lancaster Environment Centre Lancaster University Lancaster UK
| | - Susan S Hubbard
- Lawrence Berkeley National Laboratory Berkeley California USA
| | - Johan A Huisman
- Agrosphere Institute (IBG 3) Forschungszentrum Jülich GmbH Jülich Germany
| | - André Revil
- Department of Geophysics Colorado School of Mines Golden Colorado USA; ISTerre, CNRS, UMR CNRS 5275 Université de Savoie Le Bourget du Lac France
| | - David A Robinson
- Soils, Land and Ecohydrology Centre for Ecology and Hydrology Bangor UK
| | - Kamini Singha
- Department of Geology and Geological Engineering Colorado School of Mines Golden Colorado USA
| | - Lee D Slater
- Department of Earth and Environmental Sciences Rutgers-Newark New Jersey USA
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Kędzierski M, Uchman A, Sawlowicz Z, Briguglio A. Fossilized bioelectric wire - the trace fossil Trichichnus. ACTA ACUST UNITED AC 2015; 12:2301-2309. [PMID: 26290671 PMCID: PMC4538864 DOI: 10.5194/bg-12-2301-2015] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The trace fossil Trichichnus is proposed as an indicator of fossil bioelectric bacterial activity at the oxic–anoxic interface zone of marine sediments. This fulfils the idea that such processes, commonly found in the modern realm, should be also present in the geological past. Trichichnus is an exceptional trace fossil due to its very thin diameter (mostly less than 1 mm) and common pyritic filling. It is ubiquitous in some fine-grained sediments, where it has been interpreted as a burrow formed deeper than any other trace fossils, below the redox boundary. Trichichnus, formerly referred to as deeply burrowed invertebrates, has been found as remnant of a fossilized intrasediment bacterial mat that is pyritized. As visualized in 3-D by means of X-ray computed microtomography scanner, Trichichnus forms dense filamentous fabric, which reflects that it is produced by modern large, mat-forming, sulfide-oxidizing bacteria, belonging mostly to Thioploca-related taxa, which are able to house a complex bacterial consortium. Several stages of Trichichnus formation, including filamentous, bacterial mat and its pyritization, are proposed to explain an electron exchange between oxic and suboxic/anoxic layers in the sediment. Therefore, Trichichnus can be considered a fossilized “electric wire”.
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Affiliation(s)
- M Kędzierski
- Institute of Geological Sciences, Jagiellonian University, Oleandry 2a, 30-063 Kraków, Poland
| | - A Uchman
- Institute of Geological Sciences, Jagiellonian University, Oleandry 2a, 30-063 Kraków, Poland
| | - Z Sawlowicz
- Institute of Geological Sciences, Jagiellonian University, Oleandry 2a, 30-063 Kraków, Poland
| | - A Briguglio
- Institut für Paläontologie, Universität Wien, Geozentrum, Althanstrasse 14, 1090 Vienna, Austria ; Faculty of Science, Department of Petroleum Geoscience, Universiti Brunei Darussalam, Jalan Tungku Link, Gadong BE1410, Brunei
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Nielsen LP, Risgaard-Petersen N. Rethinking sediment biogeochemistry after the discovery of electric currents. ANNUAL REVIEW OF MARINE SCIENCE 2014; 7:425-442. [PMID: 25251266 DOI: 10.1146/annurev-marine-010814-015708] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The discovery of electric currents in marine sediments arose from a simple observation that conventional biogeochemistry could not explain: Sulfide oxidation in one place is closely coupled to oxygen reduction in another place, centimeters away. After experiments demonstrated that this resulted from electric coupling, the conductors were found to be long, multicellular, filamentous bacteria, now known as cable bacteria. The spatial separation of oxidation and reduction processes by these bacteria represents a shortcut in the conventional cascade of redox processes and may drive most of the oxygen consumption. In addition, it implies a separation of strong proton generators and consumers and the formation of measurable electric fields, which have several effects on mineral development and ion migration. This article reviews the work on electric currents and cable bacteria published through April 2014, with an emphasis on general trends, thought-provoking consequences, and new questions to address.
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Affiliation(s)
- Lars Peter Nielsen
- Section for Microbiology and Center for Geomicrobiology, Department of Bioscience, Aarhus University, 8000 Aarhus C, Denmark; ,
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Giampaolo V, Rizzo E, Titov K, Konosavsky P, Laletina D, Maineult A, Lapenna V. Self-potential monitoring of a crude oil-contaminated site (Trecate, Italy). ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2013; 21:8932-8947. [PMID: 24072642 DOI: 10.1007/s11356-013-2159-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Accepted: 09/10/2013] [Indexed: 06/02/2023]
Abstract
We present a multidisciplinary approach for characterization of a crude oil-contaminated site (Trecate, Italy), integrating geophysical data, such as subsoil electrical potential (in millivolts) and electrical resistivity (in ohm meters) distribution, with hydrogeological and bio-chemical data. Self-potential measurements have been evaluated together with active geoelectrical measurements and hydrological information, to provide spatial and temporal information about the self-potential sources and their possible correlations with the contamination state of the subsoil. Three self-potential surveys (March 2010, October 2010, and March 2011) were conducted at the site, both in the contaminated and uncontaminated regions. The obtained self-potential maps show large time-lapse differences in correspondence of the contaminated area, with positive electrical potential values (up to 50 mV) in spring surveys and an electrical potential dipolar distribution in October (2010) survey (amplitude from -15 to 25 mV). To understand the origin of the measured self-potential signals, a model using vertical dipolar electrical sources was built, taking into account the electrical resistivity distribution deduced from electrical resistivity tomography. The self-potential source identification allows the Trecate contamination state to be better delineated. In particular, two self-potential contributions are superimposed: the electrokinetic mechanism is predominant in spring, while the redox mechanism represents the most important contribution in autumn.
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Affiliation(s)
- V Giampaolo
- National Research Council - Institute of Methodologies for Environmental Analysis , Hydrogeosite Laboratory, Tito Scalo, Marsico Nuovo, Italy
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Hubbard CG, West LJ, Morris K, Kulessa B, Brookshaw D, Lloyd JR, Shaw S. In search of experimental evidence for the biogeobattery. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2011jg001713] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Abstract
Bacteria construct elaborate nanostructures, obtain nutrients and energy from diverse sources, synthesize complex molecules, and implement signal processing to react to their environment. These complex phenotypes require the coordinated action of multiple genes, which are often encoded in a contiguous region of the genome, referred to as a gene cluster. Gene clusters sometimes contain all of the genes necessary and sufficient for a particular function. As an evolutionary mechanism, gene clusters facilitate the horizontal transfer of the complete function between species. Here, we review recent work on a number of clusters whose functions are relevant to biotechnology. Engineering these clusters has been hindered by their regulatory complexity, the need to balance the expression of many genes, and a lack of tools to design and manipulate DNA at this scale. Advances in synthetic biology will enable the large-scale bottom-up engineering of the clusters to optimize their functions, wake up cryptic clusters, or to transfer them between organisms. Understanding and manipulating gene clusters will move towards an era of genome engineering, where multiple functions can be "mixed-and-matched" to create a designer organism.
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Affiliation(s)
- Michael Fischbach
- Department of Bioengineering and Therapeutic Sciences, University of California – San Francisco, MC 2530, Room 308C, 1700 4 Street, (415) 514-9435
| | - Christopher A. Voigt
- Department of Pharmaceutical Chemistry, University of California – San Francisco, MC 2540, Room 408C, 1700 4 Street, San Francisco, CA 94158, (415) 502-7050
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Bacteria buzzing in the seabed. Nature 2010. [DOI: 10.1038/news.2010.90] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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