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Aeppli M, Thompson A, Dewey C, Fendorf S. Redox Properties of Solid Phase Electron Acceptors Affect Anaerobic Microbial Respiration under Oxygen-Limited Conditions in Floodplain Soils. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:17462-17470. [PMID: 36342198 DOI: 10.1021/acs.est.2c05797] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Mountain floodplain soils often show spatiotemporal variations in redox conditions that arise due to changing hydrology and resulting biogeochemistry. Under oxygen-depleted conditions, solid phase terminal electron acceptors (TEAs) can be used in anaerobic respiration. However, it remains unclear to what degree the redox properties of solid phases limit respiration rates and hence organic matter degradation. Here, we assess such limitations in soils collected across a gradient in native redox states from the Slate River floodplain (Colorado, U.S.A.). We incubated soils under anoxic conditions and quantified CO2 production and microbial Fe(III) reduction, the main microbial metabolic pathway, as well as the reactivity of whole-soil solid phase TEAs toward mediated electrochemical reduction. Fe(III) reduction occurred together with CO2 production in native oxic soils, while neither Fe(II) nor CO2 production was observed in native anoxic soils. Initial CO2 production rates increased with increasing TEA redox reactivity toward mediated electrochemical reduction across all soil depths. Low TEA redox reactivity appears to be caused by elevated Fe(II) concentrations rather than crystallinity of Fe(III) phases. Our findings illustrate that the buildup of Fe(II) in systems with long residence times limits the thermodynamic viability of dissimilatory Fe(III) reduction and thereby limits the mineralization of organic carbon.
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Affiliation(s)
- Meret Aeppli
- Department of Earth System Science, Stanford University, Stanford, California94305, United States
- School of Architecture, Civil and Environmental Engineering, EPFL, 1015Lausanne, Switzerland
| | - Aaron Thompson
- Department of Crop and Soil Science, University of Georgia, Athens, Georgia30602, United States
| | - Christian Dewey
- Department of Earth System Science, Stanford University, Stanford, California94305, United States
| | - Scott Fendorf
- Department of Earth System Science, Stanford University, Stanford, California94305, United States
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Wei L, Zhu Z, Razavi BS, Xiao M, Dorodnikov M, Fan L, Yuan H, Yurtaev A, Luo Y, Cheng W, Kuzyakov Y, Wu J, Ge T. Visualization and quantification of carbon "rusty sink" by rice root iron plaque: Mechanisms, functions, and global implications. GLOBAL CHANGE BIOLOGY 2022; 28:6711-6727. [PMID: 35986445 DOI: 10.1111/gcb.16372] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Revised: 07/15/2022] [Accepted: 07/25/2022] [Indexed: 06/15/2023]
Abstract
Paddies contain 78% higher organic carbon (C) stocks than adjacent upland soils, and iron (Fe) plaque formation on rice roots is one of the mechanisms that traps C. The process sequence, extent and global relevance of this C stabilization mechanism under oxic/anoxic conditions remains unclear. We quantified and localized the contribution of Fe plaque to organic matter stabilization in a microoxic area (rice rhizosphere) and evaluated roles of this C trap for global C sequestration in paddy soils. Visualization and localization of pH by imaging with planar optodes, enzyme activities by zymography, and root exudation by 14 C imaging, as well as upscale modeling enabled linkage of three groups of rhizosphere processes that are responsible for C stabilization from the micro- (root) to the macro- (ecosystem) levels. The 14 C activity in soil (reflecting stabilization of rhizodeposits) with Fe2+ addition was 1.4-1.5 times higher than that in the control and phosphate addition soils. Perfect co-localization of the hotspots of β-glucosidase activity (by zymography) with root exudation (14 C) showed that labile C and high enzyme activities were localized within Fe plaques. Fe2+ addition to soil and its microbial oxidation to Fe3+ by radial oxygen release from rice roots increased Fe plaque (Fe3+ ) formation by 1.7-2.5 times. The C amounts trapped by Fe plaque increased by 1.1 times after Fe2+ addition. Therefore, Fe plaque formed from amorphous and complex Fe (oxyhydr)oxides on the root surface act as a "rusty sink" for organic matter. Considering the area of coverage of paddy soils globally, upscaling by model revealed the radial oxygen loss from roots and bacterial Fe oxidation may trap up to 130 Mg C in Fe plaques per rice season. This represents an important annual surplus of new and stable C to the existing C pool under long-term rice cropping.
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Affiliation(s)
- Liang Wei
- Key Laboratory of Agro-ecological Processes in Subtropical Region & Changsha Research Station for Agricultural and Environmental Monitoring, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Hunan, China
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Institute of Plant Virology, Ningbo University, Ningbo, China
| | - Zhenke Zhu
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Institute of Plant Virology, Ningbo University, Ningbo, China
| | - Bahar S Razavi
- Department of Soil and Plant Microbiome, Institute of Phytopathology, Christian-Albrechts-University of Kiel, Kiel, Germany
| | - Mouliang Xiao
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Institute of Plant Virology, Ningbo University, Ningbo, China
| | - Maxim Dorodnikov
- Department of Soil Science of Temperate Ecosystems, Department of Agricultural Soil Science, University of Goettingen, Goettingen, Germany
- Research Institute of Ecology and Natural Resources Management, Tyumen State University, Tyumen, Russia
| | - Lichao Fan
- Department of Soil Science of Temperate Ecosystems, Department of Agricultural Soil Science, University of Goettingen, Goettingen, Germany
- College of Natural Resources and Environment, Northwest A&F University, Yangling, China
| | - Hongzhao Yuan
- Key Laboratory of Agro-ecological Processes in Subtropical Region & Changsha Research Station for Agricultural and Environmental Monitoring, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Hunan, China
| | - Andrey Yurtaev
- Research Institute of Ecology and Natural Resources Management, Tyumen State University, Tyumen, Russia
| | - Yu Luo
- Institute of Soil and Water Resources and Environmental Science, Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, Zhejiang University, Hangzhou, China
| | - Weiguo Cheng
- Faculty of Agriculture, Yamagata University, Tsuruoka, Japan
| | - Yakov Kuzyakov
- Key Laboratory of Agro-ecological Processes in Subtropical Region & Changsha Research Station for Agricultural and Environmental Monitoring, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Hunan, China
- Department of Soil Science of Temperate Ecosystems, Department of Agricultural Soil Science, University of Goettingen, Goettingen, Germany
- Peoples Friendship University of Russia (RUDN University), Moscow, Russia
| | - Jinshui Wu
- Key Laboratory of Agro-ecological Processes in Subtropical Region & Changsha Research Station for Agricultural and Environmental Monitoring, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Hunan, China
| | - Tida Ge
- Key Laboratory of Agro-ecological Processes in Subtropical Region & Changsha Research Station for Agricultural and Environmental Monitoring, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Hunan, China
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Institute of Plant Virology, Ningbo University, Ningbo, China
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Hall SJ, Huang W, Napieralski SA, Roden E. Shared Microbial Taxa Respond Predictably to Cyclic Time-Varying Oxygen Limitation in Two Disparate Soils. Front Microbiol 2022; 13:866828. [PMID: 35722278 PMCID: PMC9203030 DOI: 10.3389/fmicb.2022.866828] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 05/16/2022] [Indexed: 11/27/2022] Open
Abstract
Periodic oxygen (O2) limitation in humid terrestrial soils likely influences microbial composition, but whether communities share similar responses in disparate environments remains unclear. To test if specific microbial taxa share consistent responses to anoxia in radically different soils, we incubated a rainforest Oxisol and cropland Mollisol under cyclic, time-varying anoxic/oxic cycles in the laboratory. Both soils are known to experience anoxic periods of days to weeks under field conditions; our incubation treatments consisted of anoxic periods of 0, 2, 4, 8, or 12 d followed by 4 d of oxic conditions, repeated for a total of 384 d. Taxa measured by 16S rRNA gene sequences after 48 d and 384 d of experimental treatments varied strongly with increasing anoxic period duration, and responses to anoxia often differed between soils at multiple taxonomic levels. Only 19% of the 30,356 operational taxonomic units (OTUs) occurred in both soils, and most OTUs did not respond consistently to O2 treatments. However, the OTUs present in both soils were disproportionally abundant, comprising 50% of sequences, and they often had a similar response to anoxic period duration in both soils (p < 0.0001). Overall, 67 OTUs, 36 families, 15 orders, 10 classes, and two phyla had significant and directionally consistent (positive or negative) responses to anoxic period duration in both soils. Prominent OTUs and taxonomic groups increasing with anoxic period duration in both soils included actinomycetes (Micromonosporaceae), numerous Ruminococcaceae, possible metal reducers (Anaeromyxobacter) or oxidizers (Candidatus Koribacter), methanogens (Methanomicrobia), and methanotrophs (Methylocystaceae). OTUs decreasing with anoxic duration in both soils included nitrifiers (Nitrospira) and ubiquitous unidentified Bradyrhizobiaceae and Micromonosporaceae. Even within the same genus, different OTUs occasionally showed strong positive or negative responses to anoxic duration (e.g., Dactylosporangium in the Actinobacteria), highlighting a potential for adaptation or niche partitioning in variable-O2 environments. Overall, brief anoxic periods impacted the abundance of certain microbial taxa in predictable ways, suggesting that microbial community data may partially reflect and integrate spatiotemporal differences in O2 availability within and among soils.
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Affiliation(s)
- Steven J. Hall
- Department of Ecology, Evolution and Organismal Biology, Iowa State University, Ames, IA, United States
- *Correspondence: Steven J. Hall,
| | - Wenjuan Huang
- Department of Ecology, Evolution and Organismal Biology, Iowa State University, Ames, IA, United States
| | | | - Eric Roden
- Department of Geoscience, University of Wisconsin-Madison, Madison, WI, United States
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Wang W, Tang W, Wang X, Liu W, Zhu F. Genes from Carboxypeptidase A, glutathione S-transferase, and cytochrome b families were found involved in lead transport in insect Musca domestica. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2022; 230:113113. [PMID: 34968798 DOI: 10.1016/j.ecoenv.2021.113113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 12/10/2021] [Accepted: 12/20/2021] [Indexed: 06/14/2023]
Abstract
Lead (Pb) is a typical toxic contamination source all over the world. In this research, larvae of the housefly (Musca domestica) were fed a Pb-contaminated diet at different Pb doses of 0, 20 and 5000 mg/kg. RNA sequencing was used to identify genes that were differentially expressed in relation to lead transport or detoxification. RNA interference (RNAi) was carried on 12 candidate genes. The results showed that three luminal pH regions of mid-gut were at pH values of 6.33, 3.10, and 7.80. With increasing Pb concentration, the pH of the middle mid-gut decreased by one unit. The expression levels of carboxypeptidase A (CPA1), glutathione S-transferase (GST), and cytochrome b (Cyt b) were linked to Pb treatments, particularly high Pb concentration of 5000 mg/kg. RNAi-mediated down expression of CPA1, GST2, and CYTb-c1 resulted in low Pb accumulation in the larvae of 5000 mg/kg Pb group. These proteins played key roles in Pb transport and detoxification in M. domestica larvae.
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Affiliation(s)
- Wanqiang Wang
- Hubei International Scientific and Technological Cooperation Base of Waste Conversion by Insects, Huazhong Agricultural University, Wuhan 430070, China.
| | - Wenzheng Tang
- Hubei International Scientific and Technological Cooperation Base of Waste Conversion by Insects, Huazhong Agricultural University, Wuhan 430070, China.
| | - Xiaoping Wang
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, Huazhong Agricultural University, Wuhan 430070, China.
| | - Wen Liu
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, Huazhong Agricultural University, Wuhan 430070, China.
| | - Fen Zhu
- Hubei International Scientific and Technological Cooperation Base of Waste Conversion by Insects, Huazhong Agricultural University, Wuhan 430070, China.
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Kim H, Jeon J, Lee KK, Lee YH. Compositional Shift of Bacterial, Archaeal, and Fungal Communities Is Dependent on Trophic Lifestyles in Rice Paddy Soil. Front Microbiol 2021; 12:719486. [PMID: 34539610 PMCID: PMC8440912 DOI: 10.3389/fmicb.2021.719486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Accepted: 08/16/2021] [Indexed: 11/29/2022] Open
Abstract
The soil environment determines plants’ health and performance during their life cycle. Therefore, ecological understanding on variations in soil environments, including physical, chemical, and biological properties, is crucial for managing agricultural fields. Here, we present a comprehensive and extensive blueprint of the bacterial, archaeal, and fungal communities in rice paddy soils with differing soil types and chemical properties. We discovered that natural variations of soil nutrients are important factors shaping microbial diversity. The responses of microbial diversity to soil nutrients were related to the distribution of microbial trophic lifestyles (oligotrophy and copiotrophy) in each community. The compositional changes of bacterial and archaeal communities in response to soil nutrients were mainly governed by oligotrophs, whereas copiotrophs were mainly involved in fungal compositional changes. Compositional shift of microbial communities by fertilization is linked to switching of microbial trophic lifestyles. Random forest models demonstrated that depletion of prokaryotic oligotrophs and enrichment of fungal copiotrophs are the dominant responses to fertilization in low-nutrient conditions, whereas enrichment of putative copiotrophs was important in high-nutrient conditions. Network inference also revealed that trophic lifestyle switching appertains to decreases in intra- and inter-kingdom microbial associations, diminished network connectivity, and switching of hub nodes from oligotrophs to copiotrophs. Our work provides ecological insight into how soil nutrient-driven variations in microbial communities affect soil health in modern agricultural systems.
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Affiliation(s)
- Hyun Kim
- Department of Agricultural Biotechnology, Seoul National University, Seoul, South Korea
| | - Jongbum Jeon
- Interdisciplinary Program in Agricultural Genomics, Seoul National University, Seoul, South Korea
| | - Kiseok Keith Lee
- Department of Agricultural Biotechnology, Seoul National University, Seoul, South Korea
| | - Yong-Hwan Lee
- Department of Agricultural Biotechnology, Seoul National University, Seoul, South Korea.,Interdisciplinary Program in Agricultural Genomics, Seoul National University, Seoul, South Korea.,Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, South Korea.,Center for Fungal Genetic Resources, Seoul National University, Seoul, South Korea.,Plant Genomics and Breeding Institute, Seoul National University, Seoul, South Korea.,Plant Immunity Research Center, Seoul National University, Seoul, South Korea
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Abstract
Interactions between soils and climate impact wider environmental sustainability. Soil heterogeneity intricately regulates these interactions over short spatiotemporal scales and therefore needs to be more finely examined. This paper examines how redox heterogeneity at the level of minerals, microbial cells, organic matter, and the rhizosphere entangles biogeochemical cycles in soil with climate change. Redox heterogeneity is used to develop a conceptual framework that encompasses soil microsites (anaerobic and aerobic) and cryptic biogeochemical cycling, helping to explain poorly understood processes such as methanogenesis in oxygenated soils. This framework is further shown to disentangle global carbon (C) and nitrogen (N) pathways that include CO2, CH4, and N2O. Climate-driven redox perturbations are discussed using wetlands and tropical forests as model systems. Powerful analytical methods are proposed to be combined and used more extensively to study coupled abiotic and biotic reactions that are affected by redox heterogeneity. A core view is that emerging and future research will benefit substantially from developing multifaceted analyses of redox heterogeneity over short spatiotemporal scales in soil. Taking a leap in our understanding of soil and climate interactions and their evolving influence on environmental sustainability then depends on greater collaborative efforts to comprehensively investigate redox heterogeneity spanning the domain of microscopic soil interfaces.
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Yang Y, Zhao Z, Zhang Y. Anaerobic Ammonium Removal Pathway Driven by the Fe(II)/Fe(III) Cycle through Intermittent Aeration. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:7615-7623. [PMID: 34014661 DOI: 10.1021/acs.est.0c08624] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Feammox, that is, Fe(III) reduction coupled to anaerobic ammonium oxidation, has been reported to play an important role in the nitrogen cycle in natural environments. However, the application of Feammox in wastewater treatment is limited because continuous Fe(III) supplementation is required for achieving continuous nitrogen removal, which is not feasible in practice. In this study, air was aerated intermittently into the Feammox system containing iron and high-content ammonium for oxidizing Fe(II) generated from Feammox to Fe(III), then, the produced Fe(III) participated in the next round of Feammox, leading to continuous nitrogen removal through the Fe(II)/Fe(III) cycle. The results showed that after each 10 min of aeration (150 mL/min), every 6-7 days, dissolved oxygen (DO) increased from 0 to about 0.4 mg/L, accompanied by a decrease in Fe(II) and an increase in Fe(III). One day after the aeration, DO was undetectable, and then, Fe(II) content increased and Fe(III) content decreased. On day 90, NH4+-N content in the aerated reactor was only 10.2 mg/L, while it remained at around 288.3 mg/L in the aeration-free group. X-ray diffraction showed that the generated Fe(III) through air aeration was Fe(OH)3. Microbial analysis showed that anammox and nitrification/denitrification could be excluded in the system. This NH4+ removal process, driven by the Fe(II)/Fe(III) cycle with O2 as the terminal electron acceptor, might be used as an in situ remediation method for treating high-content NH4+.
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Affiliation(s)
- Yafei Yang
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education, China), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
- School of Ecology and Environment, Zhengzhou University, Zhengzhou 450001, China
| | - Zhiqiang Zhao
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education, China), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
| | - Yaobin Zhang
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education, China), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
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Hot Spots and Hot Moments of Soil Moisture Explain Fluctuations in Iron and Carbon Cycling in a Humid Tropical Forest Soil. SOIL SYSTEMS 2018. [DOI: 10.3390/soilsystems2040059] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Soils from humid forests undergo spatial and temporal variations in moisture and oxygen (O2) in response to rainfall, and induce changes in iron (Fe) and carbon (C) biogeochemistry. We hypothesized that high rainfall periods stimulate Fe and C cycling, with the greatest effects in areas of high soil moisture. To test this, we measured Fe and C cycling across three catenas at valley, slope, and ridge positions every two days for a two-month period in a rainforest in Puerto Rico. Over 12 days without rain, soil moisture, FeII, rapidly reducible Fe oxides (FeIIIRR), and dissolved organic C (DOC) declined, but Eh and O2 increased; conversely, during a 10-day period of intense rain (290 mm), we observed the opposite trends. Mixed-effects models suggest precipitation predicted soil moisture, soil redox potential (Eh), and O2, which in turn influenced Fe reduction/oxidation, C dissolution, and mineralization processes. The approximate turnover time for HCl-extractable FeII was four days for both production and consumption, and may be driven by fluctuations in FeIIIRR, which ranged from 42% to 100% of citrate–ascorbate-extractable FeIII (short-range order (SRO)-FeIII) at a given site. Our results demonstrated that periods of high precipitation (hot moments) influenced Fe and C-cycling within day-to-week timescales, and were more pronounced in humid valleys (hot spots).
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