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Van Stan JT, Allen ST, Aubrey DP, Berry ZC, Biddick M, Coenders-Gerrits MAMJ, Giordani P, Gotsch SG, Gutmann ED, Kuzyakov Y, Magyar D, Mella VSA, Mueller KE, Ponette-González AG, Porada P, Rosenfeld CE, Simmons J, Sridhar KR, Stubbins A, Swanson T. Shower thoughts: why scientists should spend more time in the rain. Bioscience 2023; 73:441-452. [PMID: 37397836 PMCID: PMC10308363 DOI: 10.1093/biosci/biad044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Revised: 04/17/2023] [Accepted: 04/26/2023] [Indexed: 07/04/2023] Open
Abstract
Stormwater is a vital resource and dynamic driver of terrestrial ecosystem processes. However, processes controlling interactions during and shortly after storms are often poorly seen and poorly sensed when direct observations are substituted with technological ones. We discuss how human observations complement technological ones and the benefits of scientists spending more time in the storm. Human observation can reveal ephemeral storm-related phenomena such as biogeochemical hot moments, organismal responses, and sedimentary processes that can then be explored in greater resolution using sensors and virtual experiments. Storm-related phenomena trigger lasting, oversized impacts on hydrologic and biogeochemical processes, organismal traits or functions, and ecosystem services at all scales. We provide examples of phenomena in forests, across disciplines and scales, that have been overlooked in past research to inspire mindful, holistic observation of ecosystems during storms. We conclude that technological observations alone are insufficient to trace the process complexity and unpredictability of fleeting biogeochemical or ecological events without the shower thoughts produced by scientists' human sensory and cognitive systems during storms.
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Affiliation(s)
| | - Scott T Allen
- Department of Natural Resources and Environmental Science at the University of Nevada-Reno, Reno, Nevada, United States
| | - Douglas P Aubrey
- Savannah River Ecology Lab and with the Warnell School of Forestry at the University of Georgia, Athens, Georgia, United States
| | - Z Carter Berry
- Department of Biology at Wake Forest University, Winston-Salem, North Carolina, United States
| | - Matthew Biddick
- Terrestrial Ecology Research Group at the Technical University of Munich, Freising, Germany
| | | | - Paolo Giordani
- Dipartimento di Farmacia at the University of Genoa, Genoa, Italy
| | - Sybil G Gotsch
- Department of Forestry and Natural Resources at the University of Kentucky, Lexington, Kentucky, United States
| | - Ethan D Gutmann
- Research Applications Laboratory, at the National Center for Atmospheric Research, Boulder, Colorado, United States
| | - Yakov Kuzyakov
- Department of Soil Science of Temperate Systems, Agricultural Soil Science, at Georg-August-Universität, Göttingen, Germany
- Peoples Friendship University of Russia, Moscow, Russia
| | - Donát Magyar
- National Public Health Center, Budapest, Hungary
| | - Valentina S A Mella
- Sydney School of Veterinary Science, at the University of Sydney, Sydney, New South Wales, Australia
| | - Kevin E Mueller
- Department of Biological, Geological, and Environmental Sciences at Cleveland State University, Cleveland, Ohio, United States
| | - Alexandra G Ponette-González
- Department of City and Metropolitan Planning and with the Natural History Museum of Utah at the University of Utah, Salt Lake City, Utah, United States
| | - Philipp Porada
- Department of Biology at Universität Hamburg, Hamburg, Germany
| | - Carla E Rosenfeld
- Department of Minerals and Earth Sciences at the Carnegie Museum of Natural History, Pittsburgh, Pennsylvania, United States
| | - Jack Simmons
- Department of Philosophy and Religious Studies at Georgia Southern University, Statesboro, Georgia, United States
| | - Kandikere R Sridhar
- Department of Biosciences at Mangalore University, Konaje, Mangaluru, Karnataka, India
| | - Aron Stubbins
- Departments of Marine and Environmental Science, Civil and Environmental Engineering, and Chemistry and Chemical Biology at Northeastern University, Boston, Massachusetts, United States
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Xu T, Roepke EW, Flynn ED, Rosenfeld CE, Balgooyen S, Ginder-Vogel M, Schuler CJ, Santelli CM. Aqueous Co removal by mycogenic Mn oxides from simulated mining wastewaters. Chemosphere 2023; 327:138467. [PMID: 36966934 DOI: 10.1016/j.chemosphere.2023.138467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 03/05/2023] [Accepted: 03/19/2023] [Indexed: 06/18/2023]
Abstract
Naturally occurring manganese (Mn) oxide minerals often form by microbial Mn(II) oxidation, resulting in nanocrystalline Mn(III/IV) oxide phases with high reactivity that can influence the uptake and release of many metals (e.g., Ni, Cu, Co, and Zn). During formation, the structure and composition of biogenic Mn oxides can be altered in the presence of other metals, which in turn affects the minerals' ability to bind these metals. These processes are further influenced by the chemistry of the aqueous environment and the type and physiology of microorganisms involved. Conditions extending to environments that typify mining and industrial wastewaters (e.g., increased salt content, low nutrient, and high metal concentrations) have not been well investigated thus limiting the understanding of metal interactions with biogenic Mn oxides. By integrating geochemistry, microscopic, and spectroscopic techniques, we examined the capacity of Mn oxides produced by the Mn(II)-oxidizing Ascomycete fungus Periconia sp. SMF1 isolated from the Minnesota Soudan Mine to remove the metal co-contaminant Co(II) from synthetic waters that are representative of mining wastewaters currently undergoing remediation efforts. We compared two different applied remediation strategies under the same conditions: coprecipitation of Co with mycogenic Mn oxides versus adsorption of Co with pre-formed fungal Mn oxides. Co(II) was effectively removed from solution by fungal Mn oxides through two different mechanisms: incorporation into, and adsorption onto, Mn oxides. These mechanisms were similar for both remediation strategies, indicating the general effectiveness of Co(II) removal by these oxides. The mycogenic Mn oxides were primarily a nanoparticulate, poorly-crystalline birnessite-like phases with slight differences depending on the chemical conditions during formation. The relatively fast and complete removal of aqueous Co(II) during biomineralization as well as the subsequent structural incorporation of Co into the Mn oxide structure illustrated a sustainable cycle capable of continuously remediating Co(II) from metal-polluted environments.
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Affiliation(s)
- Tingying Xu
- Department of Earth and Environmental Sciences, University of Minnesota - Twin Cities, Minneapolis, MN, 55455, USA; BioTechnology Institute, University of Minnesota - Twin Cities, Saint Paul, MN, 55108, USA.
| | - Elizabeth W Roepke
- Department of Earth and Environmental Sciences, University of Minnesota - Twin Cities, Minneapolis, MN, 55455, USA; BioTechnology Institute, University of Minnesota - Twin Cities, Saint Paul, MN, 55108, USA
| | - Elaine D Flynn
- Department of Earth and Planetary Sciences, Washington University, One Brookings Drive, Saint Louis, MO, 63130, USA
| | - Carla E Rosenfeld
- Section of Minerals and Earth Sciences, Carnegie Museum of Natural History, Pittsburgh, PA, 15213, USA
| | - Sarah Balgooyen
- Department of Civil and Environmental Engineering, University of Wisconsin-Madison, 660 N. Park St., Madison, WI, 53706, USA
| | - Matthew Ginder-Vogel
- Department of Civil and Environmental Engineering, University of Wisconsin-Madison, 660 N. Park St., Madison, WI, 53706, USA
| | - Christopher J Schuler
- Department of Earth and Environmental Sciences, University of Minnesota - Twin Cities, Minneapolis, MN, 55455, USA; BioTechnology Institute, University of Minnesota - Twin Cities, Saint Paul, MN, 55108, USA
| | - Cara M Santelli
- Department of Earth and Environmental Sciences, University of Minnesota - Twin Cities, Minneapolis, MN, 55455, USA; BioTechnology Institute, University of Minnesota - Twin Cities, Saint Paul, MN, 55108, USA
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Santelli CM, Sabuda MC, Rosenfeld CE. Time-Resolved Examination of Fungal Selenium Redox Transformations. ACS Earth Space Chem 2023; 7:960-971. [PMID: 37228623 PMCID: PMC10204728 DOI: 10.1021/acsearthspacechem.2c00288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2022] [Revised: 04/21/2023] [Accepted: 04/24/2023] [Indexed: 05/27/2023]
Abstract
Selenium (Se) is both a micronutrient required for most life and an element of environmental concern due to its toxicity at high concentrations, and both bioavailability and toxicity are largely influenced by the Se oxidation state. Environmentally relevant fungi have been shown to aerobically reduce Se(IV) and Se(VI), the generally more toxic and bioavailable Se forms. The goal of this study was to shed light on fungal Se(IV) reduction pathways and biotransformation products over time and fungal growth stages. Two Ascomycete fungi were grown with moderate (0.1 mM) and high (0.5 mM) Se(IV) concentrations in batch culture over 1 month. Fungal growth was measured throughout the experiments, and aqueous and biomass-associated Se was quantified and speciated using analytical geochemistry, transmission electron microscopy (TEM), and synchrotron-based X-ray absorption spectroscopy (XAS) approaches. The results show that Se transformation products were largely Se(0) nanoparticles, with a smaller proportion of volatile, methylated Se compounds and Se-containing amino acids. Interestingly, the relative proportions of these products were consistent throughout all fungal growth stages, and the products appeared stable over time even as growth and Se(IV) concentration declined. This time-series experiment showing different biotransformation products throughout the different growth phases suggests that multiple mechanisms are responsible for Se detoxification, but some of these mechanisms might be independent of Se presence and serve other cellular functions. Knowing and predicting fungal Se transformation products has important implications for environmental and biological health as well as for biotechnology applications such as bioremediation, nanobiosensors, and chemotherapeutic agents.
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Affiliation(s)
- Cara M Santelli
- Department of Earth and Environmental Sciences, Minneapolis, Minnesota 55455, United States
- BioTechnology Institute, University of Minnesota, Saint Paul, Minnesota 55108, United States
| | - Mary C Sabuda
- Department of Earth and Environmental Sciences, Minneapolis, Minnesota 55455, United States
- BioTechnology Institute, University of Minnesota, Saint Paul, Minnesota 55108, United States
| | - Carla E Rosenfeld
- Section of Minerals and Earth Sciences, Carnegie Museum of Natural History, Pittsburgh, Pennsylvania 15213, United States
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Torgeson JM, Rosenfeld CE, Dunshee AJ, Duhn K, Schmitter R, O'Hara PA, Ng GHC, Santelli CM. Hydrobiogechemical interactions in the hyporheic zone of a sulfate-impacted, freshwater stream and riparian wetland ecosystem. Environ Sci Process Impacts 2022; 24:1360-1382. [PMID: 35661843 DOI: 10.1039/d2em00024e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Coupled abiotic and biotic processes in the hyporheic zone, where surface water and groundwater mix, play a critical role in the biogeochemical cycling of carbon, nutrients, and trace elements in streams and wetlands. Dynamic hydrologic conditions and anthropogenic pollution can impact redox gradients and biogeochemical response, although few studies examine the resulting hydrobiogeochemical interactions generated within the hyporheic zone. This study examines the effect of hyporheic flux dynamics and anthropogenic sulfate loading on the biogeochemistry of a riparian wetland and stream system. The hydrologic gradient as well as sediment, surface water, and porewater geochemistry chemistry was characterized at multiple points throughout the 2017 spring-summer-fall season at a sulfate-impacted stream flanked by wetlands in northern Minnesota. Results show that organic-rich sediments largely buffer the geochemical responses to brief or low magnitude changes in hydrologic gradient, but sustained or higher magnitude fluxes may variably alter the redox regime and, ultimately, the environmental geochemistry. This has implications for a changing climate that is expected to dramatically alter the hydrological cycle. Further, increased sulfate loading and dissolved or adsorbed ferric iron complexes in the hyporheic zone may induce a cryptic sulfur cycle linked to iron and carbon cycling, as indicated by the abundance of intermediate valence sulfur compounds (e.g., polysulfide, elemental sulfur, thiosulfate) throughout the anoxic wetland and stream-channel sediment column. The observed deviation from a classical redox tower coupled with potential changes in hydraulic gradient in these organic-rich wetland and stream hyporheic zones has implications for nutrient, trace element, and greenhouse gas fluxes into surface water and groundwater, ultimately influencing water quality and global climate.
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Affiliation(s)
- Joshua M Torgeson
- Department of Earth and Environmental Sciences, University of Minnesota, Minneapolis, MN 55455, USA.
| | - Carla E Rosenfeld
- Section of Minerals and Earth Sciences, Carnegie Museum of Natural History, USA.
| | - Aubrey J Dunshee
- Department of Earth and Environmental Sciences, University of Minnesota, Minneapolis, MN 55455, USA.
| | - Kelly Duhn
- BioTechnology Institute, University of Minnesota, St. Paul, MN 55108, USA.
| | - Riley Schmitter
- Department of Earth and Environmental Sciences, University of Minnesota, Minneapolis, MN 55455, USA.
| | - Patrick A O'Hara
- Department of Earth and Environmental Sciences, University of Minnesota, Minneapolis, MN 55455, USA.
| | - G H Crystal Ng
- Department of Earth and Environmental Sciences, University of Minnesota, Minneapolis, MN 55455, USA.
- St. Anthony Falls Laboratory, University of Minnesota, Minneapolis, MN 55455, USA
| | - Cara M Santelli
- Department of Earth and Environmental Sciences, University of Minnesota, Minneapolis, MN 55455, USA.
- BioTechnology Institute, University of Minnesota, St. Paul, MN 55108, USA.
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5
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Sabuda MC, Rosenfeld CE, DeJournett TD, Schroeder K, Wuolo-Journey K, Santelli CM. Fungal Bioremediation of Selenium-Contaminated Industrial and Municipal Wastewaters. Front Microbiol 2020; 11:2105. [PMID: 33013769 PMCID: PMC7507899 DOI: 10.3389/fmicb.2020.02105] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Accepted: 08/10/2020] [Indexed: 12/15/2022] Open
Abstract
Selenium (Se) is an essential element for most organisms yet can cause severe negative biological consequences at elevated levels. The oxidized forms of Se, selenate [Se(VI)] and selenite [Se(IV)], are more mobile, toxic, and bioavailable than the reduced forms of Se such as volatile or solid phases. Thus, selenate and selenite pose a greater threat to ecosystems and human health. As current Se remediation technologies have varying efficiencies and costs, novel strategies to remove elevated Se levels from environments impacted by anthropogenic activities are desirable. Some common soil fungi quickly remove Se (IV and VI) from solution by aerobic reduction to solid or volatile forms. Here, we perform bench-scale culture experiments of two Se-reducing Ascomycota to determine their Se removal capacity in growth media conditions containing either Se(IV) or Se(VI) as well as in Se-containing municipal (∼25 μg/L Se) and industrial (∼2000 μg/L Se) wastewaters. Dissolved Se was measured throughout the experiments to assess Se concentration and removal rates. Additionally, solid-associated Se was quantified at the end of each experiment to determine the amount of Se removed to solid phases (e.g., Se(0) nanoparticles, biomass-adsorbed Se, or internal organic selenoproteins). Results show that under optimal conditions, fungi more efficiently remove Se(IV) from solution compared to Se(VI). Additionally, both fungi remove a higher percentage of Se from the filtered municipal wastewater compared to the industrial wastewater, though cultures in industrial wastewater retained a greater amount of solid-associated Se. Additional wastewater experiments were conducted with supplemental carbohydrate- or glycerin-based carbon products and additional nitrogen- and phosphorous-containing nutrients in some cases to enhance fungal growth. Relative to unamended wastewater experiments, supplemental carbohydrates promote Se removal from municipal wastewater but minimally impact industrial wastewater removal. This demonstrates that carbon availability and source impacts fungal Se reduction and removal from solution. Calculations to assess the leaching potential of solid-associated Se from fungal biomass show that wastewater Se release will not exceed regulatory limits. This study highlights the considerable potential for the mycoremediation of Se-contaminated wastewaters.
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Affiliation(s)
- Mary C Sabuda
- Department of Earth and Environmental Sciences, University of Minnesota, Minneapolis, MN, United States.,BioTechnology Institute, University of Minnesota, Saint Paul, MN, United States
| | - Carla E Rosenfeld
- Section of Minerals and Earth Sciences, Carnegie Museum of Natural History, Pittsburgh, PA, United States
| | | | - Katie Schroeder
- Department of Earth and Environmental Sciences, University of Minnesota, Minneapolis, MN, United States.,Department of Ecology, Evolution, and Behavior, University of Minnesota, Saint Paul, MN, United States
| | | | - Cara M Santelli
- Department of Earth and Environmental Sciences, University of Minnesota, Minneapolis, MN, United States.,BioTechnology Institute, University of Minnesota, Saint Paul, MN, United States
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Rosenfeld CE, Sabuda MC, Hinkle MAG, James BR, Santelli CM. A Fungal-Mediated Cryptic Selenium Cycle Linked to Manganese Biogeochemistry. Environ Sci Technol 2020; 54:3570-3580. [PMID: 32083848 DOI: 10.1021/acs.est.9b06022] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Selenium (Se) redox chemistry is a determining factor for its environmental toxicity and mobility. Currently, millions of people are impacted by Se deficiency or toxicity, and in geologic history, several mass extinctions have been linked to extreme Se deficiency. Importantly, microbial activity and interactions with other biogeochemically active elements can drastically alter Se oxidation state and form, impacting its bioavailability. Here, we use wet geochemistry, spectroscopy, and electron microscopy to identify a cryptic, or hidden, Se cycle involving the reoxidation of biogenic volatile Se compounds in the presence of biogenic manganese [Mn(III, IV)] oxides and oxyhydroxides (hereafter referred to as "Mn oxides"). Using two common environmental Ascomycete fungi, Paraconiothyrium sporulosum and Stagonospora sp., we observed that aerobic Se(IV and VI) bioreduction to Se(0) and Se(-II) occurs simultaneously alongside the opposite redox biomineralization process of mycogenic Mn(II) oxidation to Mn oxides. Selenium bioreduction produced stable Se(0) nanoparticles and organoselenium compounds. However, mycogenic Mn oxides rapidly oxidized volatile Se products, recycling these compounds back to soluble forms. Given their abundance in natural systems, biogenic Mn oxides likely play an important role mediating Se biogeochemistry. Elucidating this cryptic Se cycle is essential for understanding and predicting Se behavior in diverse environmental systems.
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Affiliation(s)
- Carla E Rosenfeld
- Department of Earth and Environmental Sciences, University of Minnesota - Twin Cities, Minneapolis, Minnesota 55455, United States
- BioTechnology Institute, University of Minnesota - Twin Cities, St. Paul, Minnesota 55108, United States
| | - Mary C Sabuda
- Department of Earth and Environmental Sciences, University of Minnesota - Twin Cities, Minneapolis, Minnesota 55455, United States
- BioTechnology Institute, University of Minnesota - Twin Cities, St. Paul, Minnesota 55108, United States
| | - Margaret A G Hinkle
- Department of Geology, Washington & Lee University, Lexington, Virginia 24450, United States
| | - Bruce R James
- Department of Environmental Science & Technology, University of Maryland - College Park, College Park, Maryland 20742, United States
| | - Cara M Santelli
- Department of Earth and Environmental Sciences, University of Minnesota - Twin Cities, Minneapolis, Minnesota 55455, United States
- BioTechnology Institute, University of Minnesota - Twin Cities, St. Paul, Minnesota 55108, United States
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Rosenfeld CE, Chaney RL, Martínez CE. Soil geochemical factors regulate Cd accumulation by metal hyperaccumulating Noccaea caerulescens (J. Presl & C. Presl) F.K. Mey in field-contaminated soils. Sci Total Environ 2018; 616-617:279-287. [PMID: 29121576 DOI: 10.1016/j.scitotenv.2017.11.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Revised: 10/30/2017] [Accepted: 11/01/2017] [Indexed: 06/07/2023]
Abstract
Cadmium contamination in soil is a substantial global problem, and of significant concern due to high food-chain transfer. Cadmium hyperaccumulators are of particular interest because of their ability to tolerate and take up significant amounts of heavy metal pollution from soils. One particular plant, Noccaea caerulescens (formerly, Thlaspi caerulescens), has been extensively studied in terms of its capacity to accumulate heavy metals (specifically Zn and Cd), though these studies have primarily utilized hydroponic and metal-spiked model soil systems. We studied Cd and nutrient uptake by two N. caerulescens ecotypes, Prayon (Zn-only hyperaccumulator) and Ganges (Zn- and Cd-hyperaccumulator) in four long-term field-contaminated soils. Our data suggest that individual soil properties such as total soil Cd, Zn:Cd molar ratio, or soil pH do not accurately predict Cd uptake by hyperaccumulating plants. Additionally, total Cd uptake by the hyperaccumulating Ganges ecotype was substantially less than its physiological capacity, which is likely due to Cd-containing solid phases (primarily iron oxides) and pH that play an important role in regulating and limiting Cd solubility. Increased P accumulation in the Ganges leaves, and greater plant Fe accumulation from Cd-containing soils suggests that rhizosphere alterations via proton, and potentially organic acid, secretion may also play a role in nutrient and Cd acquisition by the plant roots. The current study highlights the role that soil geochemical factors play in influencing Cd uptake by hyperaccumulating plants. While these plants may have high physiological potential to accumulate metals from contaminated soils, individual soil geochemical factors and the plant-soil interactions in that soil will dictate the actual amount of phytoextractable metal. This underlines the need for site-specific understanding of metal-containing solid phases and geochemical properties of soils before undertaking phytoextraction efforts.
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Affiliation(s)
- Carla E Rosenfeld
- Department of Ecosystem Science and Management, The Pennsylvania State University, University Park, PA 16802, United States.
| | - Rufus L Chaney
- Adaptive Cropping Systems Laboratory, U.S. Department of Agriculture, Agricultural Research Service, Beltsville, MD 20705, United States
| | - Carmen E Martínez
- Department of Ecosystem Science and Management, The Pennsylvania State University, University Park, PA 16802, United States
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Rosenfeld CE, Kenyon JA, James BR, Santelli CM. Selenium (IV,VI) reduction and tolerance by fungi in an oxic environment. Geobiology 2017; 15:441-452. [PMID: 28044397 DOI: 10.1111/gbi.12224] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Accepted: 12/07/2016] [Indexed: 05/27/2023]
Abstract
Microbial processes are known to mediate selenium (Se) oxidation-reduction reactions, strongly influencing Se speciation, bioavailability, and transport throughout the environment. While these processes have commonly been studied in anaerobic bacteria, the role that aerobic fungi play in Se redox reactions could be important for Se-rich soil systems, dominated by microbial activity. We quantified fungal growth, aerobic Se(IV, VI) reduction, and Se immobilization and volatilization in the presence of six, metal-tolerant Ascomycete fungi. We found that the removal of dissolved Se was dependent on the fungal species, Se form (i.e., selenite or selenate), and Se concentration. All six species grew and removed dissolved Se(IV) or Se(VI) from solution, with five species reducing both oxyanions to Se(0) biominerals, and all six species removing at least 15%-20% of the supplied Se via volatilization. Growth rates of all fungi, however, decreased with increasing Se(IV,VI) concentrations. All fungi removed 85%-93% of the dissolved Se(IV) within 10 d in the presence of 0.01 mm Se(IV), although only about 20%-30% Se(VI) was removed when grown with 0.01 mm Se(VI). Fungi-produced biominerals were typically 50- to 300-nm-diameter amorphous or paracrystalline spherical Se(0) nanoparticles. Our results demonstrate that activity of common soil fungi can influence Se form and distribution, and these organisms may therefore play a role in detoxifying Se-polluted environments.
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Affiliation(s)
- C E Rosenfeld
- Department of Mineral Sciences, Smithsonian Institution National Museum of Natural History, Washington, DC, USA
- Department of Earth Science and BioTechnology Institute, University of Minnesota - Twin Cities, Minneapolis, MN, USA
| | - J A Kenyon
- Department of Mineral Sciences, Smithsonian Institution National Museum of Natural History, Washington, DC, USA
- MIT/WHOI Joint Program in Oceanography, Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA, USA
| | - B R James
- Department of Environmental Science and Technology, University of Maryland, College Park, MD, USA
| | - C M Santelli
- Department of Mineral Sciences, Smithsonian Institution National Museum of Natural History, Washington, DC, USA
- Department of Earth Science and BioTechnology Institute, University of Minnesota - Twin Cities, Minneapolis, MN, USA
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Rosenfeld CE, Chaney RL, Tappero RV, Martínez CE. Microscale Investigations of Soil Heterogeneity: Impacts on Zinc Retention and Uptake in Zinc-Contaminated Soils. J Environ Qual 2017; 46:373-383. [PMID: 28380570 DOI: 10.2134/jeq2016.05.0184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Metal contaminants in soils can persist for millennia, causing lasting negative impacts on local ecosystems. Long-term contaminant bioavailability is related to soil pH and to the strength and stability of solid-phase associations. We combined physical density separation with synchrotron-based microspectroscopy to reduce solid-phase complexity and to study Zn speciation in field-contaminated soils. We also investigated Zn uptake in two Zn-hyperaccumulating ecotypes of (Ganges and Prayon). Soils were either moderately contaminated (500-800 mg Zn kg via contaminated biosolids application) or grossly enriched (26,000 mg Zn kg via geogenic enrichment). Soils were separated using sodium polytungstate into three fractions: light fraction (LF) (<1.6 g cm), medium fraction (MF) (1.6-2.8 g cm), and heavy fraction (HF) (>2.8 g cm). Approximately 45% of the total Zn was associated with MF in biosolids-contaminated soils. From these data, we infer redistribution to the MF after biosolids application because Zn in biosolids is principally associated with HF and LF. Our results suggest that increasing proportions of HF-associated Zn in soils may be related to greater relative Zn removal by Zn hyperaccumulating plants. Using density fractions enabled assessment of Zn speciation on a microscale despite incomplete fractionation. Analyzing both density fractions and whole soils revealed certain phases (e.g., ZnS, Zn coprecipitated with Fe oxides) that were not obvious in all analyses, indicating multiple views of the same soils enable a more complete understanding of Zn speciation.
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