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Ma J, Zhou M, Peng Y, Tuo Y, Zhou C, Liu K, Huang Y, He F, Lai Q, Zhang Z, Kinouchi T, Li S, Xu X, Wu X, Lin X, Li W, Wang G. Instability in a carbon pool driven by multiple dissolved organic matter sources in a eutrophic lake basin: Potential factors for increased greenhouse gas emissions. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2024; 350:119697. [PMID: 38035504 DOI: 10.1016/j.jenvman.2023.119697] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Revised: 11/06/2023] [Accepted: 11/21/2023] [Indexed: 12/02/2023]
Abstract
Lakes serve as vital reservoirs of dissolved organic matter (DOM) and play pivotal roles in biogeochemical carbon cycles. However, the sources and compositions of DOM in freshwater lakes and their potential effects on lake sediment carbon pools remain unclear. In this study, seven inflowing rivers in the Lake Taihu basin were selected to explore the potential effects of multi-source DOM inputs on the stability of the lake sediment carbon pool. The results showed the high concentrations of dissolved organic carbon in the Lake Taihu basin, accompanied by a high complexity level. Lignins constituted the majority of DOM compounds, surpassing 40% of the total, while the organic carbon content was predominantly composed of humic acids (1.02-3.01 g kg-1). The high amounts of lignin oxidative cleavage led to CHO being the main molecular structure in the DOM of the seven rivers. The carbon constituents within the sediment carbon reservoir exhibited a positive correlation with dissolved CH4 and CO2, with a notable emphasis on humic acid and dissolved CH4 (R2 = 0.86). The elevated concentration of DOM, coupled with its intricate composition, contributed to the increases in dissolved greenhouse gases (GHGs). Experiments showed that the mixing of multi-source DOM can accelerate the organic carbon mineralization processes. The unit carbon emission efficiency was highest in the mixed group, reaching reached 160.9 μmol∙Cg-1, which also exhibited a significantly different carbon pool. The mixed decomposition of DOM from different sources influenced the roles of the lake carbon pool as source and sink, indicating that the multi-source DOM of this lake basin was a potential driving factor for increased carbon emissions. These findings have improved our understanding of the sources and compositions of DOM in lake basins and revealed their impacts on carbon emissions, thereby providing a theoretical basis for improving assessments of lake carbon emissions.
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Affiliation(s)
- Jie Ma
- Ministry of Ecology and Environment, Nanjing Institute of Environment Sciences, Nanjing, 210042, China
| | - Muchun Zhou
- Department of Applied Physics and Chemical Engineering, Tokyo University of Agriculture and Technology, Tokyo, 184-8588, Japan
| | - Yu Peng
- Department of Transdisciplinary Science and Engineering, Tokyo Institute of Technology, Tokyo, 152-8550, Japan
| | - Ya Tuo
- Environmental Development Center of the Ministry of Ecology and Environment, Beijing, 100029, China
| | - Chuanqiao Zhou
- Department of Transdisciplinary Science and Engineering, Tokyo Institute of Technology, Tokyo, 152-8550, Japan.
| | - Kexin Liu
- Department of Transdisciplinary Science and Engineering, Tokyo Institute of Technology, Tokyo, 152-8550, Japan
| | - Yilin Huang
- Department of Transdisciplinary Science and Engineering, Tokyo Institute of Technology, Tokyo, 152-8550, Japan
| | - Fei He
- Ministry of Ecology and Environment, Nanjing Institute of Environment Sciences, Nanjing, 210042, China.
| | - Qiuying Lai
- Ministry of Ecology and Environment, Nanjing Institute of Environment Sciences, Nanjing, 210042, China
| | - Zhihui Zhang
- School of Environment, Nanjing Normal University, Nanjing, 210023, China
| | - Tsuyoshi Kinouchi
- Department of Transdisciplinary Science and Engineering, Tokyo Institute of Technology, Tokyo, 152-8550, Japan
| | - Shuyin Li
- Department of Transdisciplinary Science and Engineering, Tokyo Institute of Technology, Tokyo, 152-8550, Japan; Yangtze River Basin Ecological Environment Monitoring and Scientific Research Center, Yangtze River Basin Ecological Environment Supervision and Administration Bureau, Ministry of Ecological Environment, Wuhan, 430010, China
| | - Xiaoguang Xu
- School of Environment, Nanjing Normal University, Nanjing, 210023, China
| | - Xiaodong Wu
- College of Urban and Environmental Sciences, Hubei Normal University, Huangshi, 435002, China
| | - Xiaowen Lin
- College of Urban and Environmental Sciences, Hubei Normal University, Huangshi, 435002, China
| | - Weixin Li
- Ministry of Ecology and Environment, Nanjing Institute of Environment Sciences, Nanjing, 210042, China
| | - Guoxiang Wang
- School of Environment, Nanjing Normal University, Nanjing, 210023, China
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Hu D, Zeng Q, Zhu J, He C, Shi Q, Dong H. Promotion of Humic Acid Transformation by Abiotic and Biotic Fe Redox Cycling in Nontronite. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:19760-19771. [PMID: 37972299 DOI: 10.1021/acs.est.3c05646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2023]
Abstract
The redox activity of Fe-bearing minerals is coupled with the transformation of organic matter (OM) in redox dynamic environments, but the underlying mechanism remains unclear. In this work, a Fe redox cycling experiment of nontronite (NAu-2), an Fe-rich smectite, was performed via combined abiotic and biotic methods, and the accompanying transformation of humic acid (HA) as a representative OM was investigated. Chemical reduction and subsequent abiotic reoxidation of NAu-2 produced abundant hydroxyl radicals (thereafter termed as ·OH) that effectively transformed the chemical and molecular composition of HA. More importantly, transformed HA served as a more premium electron donor/carbon source to couple with subsequent biological reduction of Fe(III) in reoxidized NAu-2 by Geobacter sulfurreducens, a model Fe-reducing bacterium. Destruction of aromatic structures and formation of carboxylates were mechanisms responsible for transforming HA into an energetically more bioavailable substrate. Relative to unaltered HA, transformed HA increased the extent of the bioreduction by 105%, and Fe(III) reduction was coupled with oxidation and even mineralization of transformed HA, resulting in bleached HA and formation of microbial products and cell debris. ·OH transformation slightly decreased the electron shuttling capacity of HA in bioreduction. Our results provide a mechanistic explanation for rapid OM mineralization driven by Fe redox cycling in redox-fluctuating environments.
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Affiliation(s)
- Dafu Hu
- Center for Geomicrobiology and Biogeochemistry Research, State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing 100083, China
- School of Earth Sciences and Resources, China University of Geosciences, Beijing 100083, China
| | - Qiang Zeng
- Center for Geomicrobiology and Biogeochemistry Research, State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing 100083, China
- School of Earth Sciences and Resources, China University of Geosciences, Beijing 100083, China
- Frontiers Science Center for Deep-time Digital Earth, China University of Geosciences (Beijing), Beijing 100083, China
| | - Jin Zhu
- Zhejiang Institute of Metrology, Hangzhou, Zhejiang 310018, China
| | - Chen He
- State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Beijing 102249, China
| | - Quan Shi
- State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Beijing 102249, China
| | - Hailiang Dong
- Center for Geomicrobiology and Biogeochemistry Research, State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing 100083, China
- School of Earth Sciences and Resources, China University of Geosciences, Beijing 100083, China
- Frontiers Science Center for Deep-time Digital Earth, China University of Geosciences (Beijing), Beijing 100083, China
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3
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Niu C, Weng L, Lian W, Zhang R, Ma J, Chen Y. Carbon sequestration in paddy soils: Contribution and mechanisms of mineral-associated SOC formation. CHEMOSPHERE 2023; 333:138927. [PMID: 37187382 DOI: 10.1016/j.chemosphere.2023.138927] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Revised: 05/09/2023] [Accepted: 05/11/2023] [Indexed: 05/17/2023]
Abstract
In this work, comparative study of paddy and upland soils were carried out to unravel mechanisms of enhanced soil organic carbon (SOC) sequestration in paddy soils using fractionation methods, 13C NMR and Nano-SIMS analysis, as well as organic layer thickness calculations (Core-Shell model). The results showed that although there is a strong increase in particulate SOC in paddy soils compared to that in the upland soils, the increase in mineral-associated SOC is more important, explaining 60-75% of SOC increase in the paddy soils. In the wet and dry alternate cycles of paddy soil, iron (hydr)oxides adsorb relatively small and soluble organic molecules (fulvic acid-like), promote catalytic oxidation and polymerization, thus accelerating formation of larger organic molecules. Upon reductive iron dissolution, these molecules are released and incorporated into existing less soluble organic compounds (humic acid or humin-like), which are coagulated and associated with clay minerals, becoming part of the mineral-associated SOC. The functioning of this "iron wheel" process stimulates accumulation of relatively young SOC into mineral-associated organic carbon pool, and reduces the difference in chemical structure between oxides-bound and clay-bound SOC. Further, the faster turnover of oxides and soil aggregates in paddy soil also facilities interaction between SOC and minerals. The formation of mineral-associated SOC may delay degradation of organic matter during both wet and dry period in the paddy field, therefore enhancing carbon sequestration in paddy soils.
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Affiliation(s)
- Cuiyun Niu
- Key Laboratory for Environmental Factors Control of Agro-Product Quality Safety, Ministry of Agriculture and Rural Affairs, Tianjin, 300191, China; Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs, Tianjin, 300191, China; Cangzhou Academy of Agriculture and Forestry Sciences, Cangzhou, 061000, China
| | - Liping Weng
- Key Laboratory for Environmental Factors Control of Agro-Product Quality Safety, Ministry of Agriculture and Rural Affairs, Tianjin, 300191, China; Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs, Tianjin, 300191, China; Department of Soil Quality, Wageningen University, P.O. Box 47, 6700 AA, Wageningen, the Netherlands.
| | - Wanli Lian
- Key Laboratory for Environmental Factors Control of Agro-Product Quality Safety, Ministry of Agriculture and Rural Affairs, Tianjin, 300191, China; Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs, Tianjin, 300191, China
| | - Ran Zhang
- Key Laboratory for Environmental Factors Control of Agro-Product Quality Safety, Ministry of Agriculture and Rural Affairs, Tianjin, 300191, China; Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs, Tianjin, 300191, China
| | - Jie Ma
- Key Laboratory for Environmental Factors Control of Agro-Product Quality Safety, Ministry of Agriculture and Rural Affairs, Tianjin, 300191, China; Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs, Tianjin, 300191, China
| | - Yali Chen
- Key Laboratory for Environmental Factors Control of Agro-Product Quality Safety, Ministry of Agriculture and Rural Affairs, Tianjin, 300191, China; Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs, Tianjin, 300191, China
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LaFond-Hudson S, Sulman B. Modeling strategies and data needs for representing coastal wetland vegetation in land surface models. THE NEW PHYTOLOGIST 2023; 238:938-951. [PMID: 36683447 DOI: 10.1111/nph.18760] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Accepted: 01/10/2023] [Indexed: 06/17/2023]
Abstract
Vegetated coastal ecosystems sequester carbon rapidly relative to terrestrial ecosystems. Coastal wetlands are poorly represented in land surface models, but work is underway to improve process-based, predictive modeling of these ecosystems. Here, we identify guiding questions, potential simulations, and data needs to make progress in improving representation of vegetation in terrestrial-aquatic interfaces, with a focus on coastal and estuarine ecosystems. We synthesize relevant plant traits and environmental controls on vegetation that influence carbon cycling in coastal ecosystems. We propose that models include separate plant functional types (PFTs) for mangroves, graminoid salt marshes, and succulent salt marshes to adequately represent the variation in aboveground and belowground productivity between common coastal wetland vegetation types. We also discuss the drivers and carbon storage consequences of shifts in dominant PFTs. We suggest several potential approaches to represent the diversity in vegetation tolerance and adaptations to fluctuations in salinity and water level, which drive key gradients in coastal wetland ecosystems. Finally, we discuss data needs for parameterizing and evaluating model implementations of coastal wetland vegetation types and function.
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Affiliation(s)
- Sophia LaFond-Hudson
- Environmental Sciences Division, Oak Ridge National Laboratory, 1 Bethel Valley Rd, Oak Ridge, TN, 37917, USA
| | - Benjamin Sulman
- Environmental Sciences Division, Oak Ridge National Laboratory, 1 Bethel Valley Rd, Oak Ridge, TN, 37917, USA
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5
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Biogeochemistry of Iron Enrichment in Groundwater: An Indicator of Environmental Pollution and Its Management. SUSTAINABILITY 2022. [DOI: 10.3390/su14127059] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Iron (Fe) is one of the most biochemically active and widely distributed elements and one of the most important elements for biota and human activities. Fe plays important roles in biological and chemical processes. Fe redox reactions in groundwater have been attracting increasing attention in the geochemistry and biogeochemistry fields. This study reviews recent research into Fe redox reactions and biogeochemical Fe enrichment processes, including reduction, biotic and abiotic oxidation, adsorption, and precipitation in groundwater. Fe biogeochemistry in groundwater and the water-bearing medium (aquifer) often involves transformation between Fe(II) and Fe(III) caused by the biochemical conditions of the groundwater system. Human activities and anthropogenic pollutants strongly affect these conditions. Generally speaking, acidification, anoxia and warming of groundwater environments, as well as the inputs of reducing pollutants, are beneficial to the migration of Fe into groundwater (Fe(III)→Fe(II)); conversely, it is beneficial to the migration of it into the media (Fe(II)→Fe(III)). This study describes recent progress and breakthroughs and assesses the biogeochemistry of Fe enrichment in groundwater, factors controlling Fe reactivity, and Fe biogeochemistry effects on the environment. This study also describes the implications of Fe biogeochemistry for managing Fe in groundwater, including the importance of Fe in groundwater monitoring and evaluation, and early groundwater pollution warnings.
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Affiliation(s)
| | | | - Erland Bååth
- Section of Microbial Ecology Department of Biology Lund University 22362 Lund Sweden
| | - Patrick Meir
- School of Geosciences University of Edinburgh Crew Building, Kings Buildings Edinburgh UK
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7
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Huang W, Wang K, Ye C, Hockaday WC, Wang G, Hall SJ. High carbon losses from oxygen-limited soils challenge biogeochemical theory and model assumptions. GLOBAL CHANGE BIOLOGY 2021; 27:6166-6180. [PMID: 34464997 DOI: 10.1111/gcb.15867] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 07/28/2021] [Accepted: 08/24/2021] [Indexed: 06/13/2023]
Abstract
Oxygen (O2 ) limitation contributes to persistence of large carbon (C) stocks in saturated soils. However, many soils experience spatiotemporal O2 fluctuations impacted by climate and land-use change, and O2 -mediated climate feedbacks from soil greenhouse gas emissions remain poorly constrained. Current theory and models posit that anoxia uniformly suppresses carbon (C) decomposition. Here we show that periodic anoxia may sustain or even stimulate decomposition over weeks to months in two disparate soils by increasing turnover and/or size of fast-cycling C pools relative to static oxic conditions, and by sustaining decomposition of reduced organic molecules. Cumulative C losses did not decrease consistently as cumulative O2 exposure decreased. After >1 year, soils anoxic for 75% of the time had similar C losses as the oxic control but nearly threefold greater climate impact on a CO2 -equivalent basis (20-year timescale) due to high methane (CH4 ) emission. A mechanistic model incorporating current theory closely reproduced oxic control results but systematically underestimated C losses under O2 fluctuations. Using a model-experiment integration (ModEx) approach, we found that models were improved by varying microbial maintenance respiration and the fraction of CH4 production in total C mineralization as a function of O2 availability. Consistent with thermodynamic expectations, the calibrated models predicted lower microbial C-use efficiency with increasing anoxic duration in one soil; in the other soil, dynamic organo-mineral interactions implied by our empirical data but not represented in the model may have obscured this relationship. In both soils, the updated model was better able to capture transient spikes in C mineralization that occurred following anoxic-oxic transitions, where decomposition from the fluctuating-O2 treatments greatly exceeded the control. Overall, our data-model comparison indicates that incorporating emergent biogeochemical properties of soil O2 variability will be critical for effectively modeling C-climate feedbacks in humid ecosystems.
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Affiliation(s)
- Wenjuan Huang
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, Iowa, USA
| | - Kefeng Wang
- College of Life Science, Northwest University, Xi'an, China
| | - Chenglong Ye
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, Iowa, USA
- Ecosystem Ecology Lab, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, China
| | | | - Gangsheng Wang
- Institute for Water-Carbon Cycles and Carbon Neutrality, and State Key Laboratory of Water Resources and Hydropower Engineering Sciences, Wuhan University, Wuhan, China
| | - Steven J Hall
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, Iowa, USA
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8
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Chen N, Fu Q, Wu T, Cui P, Fang G, Liu C, Chen C, Liu G, Wang W, Wang D, Wang P, Zhou D. Active Iron Phases Regulate the Abiotic Transformation of Organic Carbon during Redox Fluctuation Cycles of Paddy Soil. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:14281-14293. [PMID: 34623154 DOI: 10.1021/acs.est.1c04073] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Iron (Fe) phases are tightly linked to the preservation rather than the loss of organic carbon (OC) in soil; however, during redox fluctuations, OC may be lost due to Fe phase-mediated abiotic processes. This study examined the role of Fe phases in driving hydroxyl radical (•OH) formation and OC transformation during redox cycles in paddy soils. Chemical probes, sequential extraction, and Mössbauer analyses showed that the active Fe species, such as exchangeable and surface-bound Fe and Fe in low-crystalline minerals (e.g., green rust-like Fe phases), predominantly regulated •OH formation during redox cycles. The •OH oxidation strongly induced the oxidative transformation of OC, which accounted for 15.1-30.8% of CO2 production during oxygenation. Microbial processes contributed 7.3-12.1% of CO2 production, as estimated by chemical quenching and γ-irradiation experiments. After five redox cycles, 30.1-71.9% of the OC associated with active Fe species was released, whereas 5.2-7.1% was stabilized by high-crystalline Fe phases due to the irreversible transformation of these active Fe species during redox cycles. Collectively, our findings might unveil the under-appreciated role of active Fe phases in driving more loss than conservation of OC in soil redox fluctuation events.
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Affiliation(s)
- Ning Chen
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, P.R. China
| | - Qinglong Fu
- School of Environmental Studies, China University of Geosciences (Wuhan), Wuhan 430078, P.R. China
| | - Tongliang Wu
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, P.R. China
| | - Peixin Cui
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, P.R. China
| | - Guodong Fang
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, P.R. China
| | - Cun Liu
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, P.R. China
| | - Chunmei Chen
- Institute of Surface-Earth System Science, Tianjin University, Tianjin 300072, P.R. China
| | - Guangxia Liu
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, P.R. China
| | - Wenchao Wang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, P.R. China
| | - Dixiang Wang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, P.R. China
| | - Peng Wang
- College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, P.R. China
| | - Dongmei Zhou
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, P.R. China
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Huang J, Jones A, Waite TD, Chen Y, Huang X, Rosso KM, Kappler A, Mansor M, Tratnyek PG, Zhang H. Fe(II) Redox Chemistry in the Environment. Chem Rev 2021; 121:8161-8233. [PMID: 34143612 DOI: 10.1021/acs.chemrev.0c01286] [Citation(s) in RCA: 147] [Impact Index Per Article: 49.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Iron (Fe) is the fourth most abundant element in the earth's crust and plays important roles in both biological and chemical processes. The redox reactivity of various Fe(II) forms has gained increasing attention over recent decades in the areas of (bio) geochemistry, environmental chemistry and engineering, and material sciences. The goal of this paper is to review these recent advances and the current state of knowledge of Fe(II) redox chemistry in the environment. Specifically, this comprehensive review focuses on the redox reactivity of four types of Fe(II) species including aqueous Fe(II), Fe(II) complexed with ligands, minerals bearing structural Fe(II), and sorbed Fe(II) on mineral oxide surfaces. The formation pathways, factors governing the reactivity, insights into potential mechanisms, reactivity comparison, and characterization techniques are discussed with reference to the most recent breakthroughs in this field where possible. We also cover the roles of these Fe(II) species in environmental applications of zerovalent iron, microbial processes, biogeochemical cycling of carbon and nutrients, and their abiotic oxidation related processes in natural and engineered systems.
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Affiliation(s)
- Jianzhi Huang
- Department of Civil and Environmental Engineering, Case Western Reserve University, 2104 Adelbert Road, Cleveland, Ohio 44106, United States
| | - Adele Jones
- UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, New South Wales 2052, Australia
| | - T David Waite
- UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Yiling Chen
- Institute of Environmental and Ecological Engineering, Guangdong University of Technology, Guangzhou 510006, China
| | - Xiaopeng Huang
- Physical Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Kevin M Rosso
- Physical Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Andreas Kappler
- Geomicrobiology, Center for Applied Geosciences, University of Tuebingen, 72076 Tuebingen, Germany
| | - Muammar Mansor
- Geomicrobiology, Center for Applied Geosciences, University of Tuebingen, 72076 Tuebingen, Germany
| | - Paul G Tratnyek
- School of Public Health, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, Oregon 97239, United States
| | - Huichun Zhang
- Department of Civil and Environmental Engineering, Case Western Reserve University, 2104 Adelbert Road, Cleveland, Ohio 44106, United States
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Wang Y, Zhu Z, Xia Y, Zhong M, Ma R, Zhao Y, Yan Q, Miao Q, Wang B, Ma Y, Yin X, Zhou Y. Accessing the position-specific 18O/ 16O ratios of lignin monomeric units from higher plants with highly selective hydrogenolysis followed by GC/Py/IRMS analysis. Anal Chim Acta 2021; 1171:338667. [PMID: 34112441 DOI: 10.1016/j.aca.2021.338667] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 04/30/2021] [Accepted: 05/19/2021] [Indexed: 11/26/2022]
Abstract
The 18O/16O of lignin at bulk, molecular and positional levels can be used to extract valuable information about climate, plant growth environment, plant physiology, and plant metabolism. Access to the individual oxygen isotope compositions (δ18O) in the lignin monomeric units is, however, challenging as depolymerization of lignin to release the monomeric units may cause isotope fractionation. We have developed a novel method to measure the δ18O of the three oxygens (O-3, O-4 and O-5) attached to the aromatic ring of the monomeric units (bearing no oxygen in their side chains) releasable by highly selective W2C/AC (tungsten carbide supported by activated carbon)-catalyzed hydrogenolysis of lignin. O-4 is obtained by measuring the δ18O of H-type monomeric unit, while O-3 and O-5 can be calculated following isotope mass balance between H, G and S-type monomeric units measurable simultaneously with GC/Py/IRMS (gas chromatography-pyrolysis-isotope ratio mass spectrometry). The measurement precisions are better than 1.15 mUr and 4.15 mUr at molecular and positional levels, respectively. It was shown that there were a δ18OH > δ18OG > δ18OS isotopic order in the herbaceous plant lignin and an (inclusive) opposite order in woody plant lignin. Such differences in isotopic order is likely to be caused by the fact that both L-tyrosine, which carries an 18O-enriched leaf water signal, and L-phenylalanine, which carries mainly a molecular O2 isotopic signal, serve as the precursors for lignin biosynthesis in herbaceous plants while only the latter serves as precursor for lignin biosynthesis in woody plants. We have highlighted the potential application of such molecular and positional levels isotopic signals in plant physiological, metabolic, lignin biosynthetic and climate studies.
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Affiliation(s)
- Ying Wang
- Isotopomics in Chemical Biology (ICB) & Key Laboratory of Chemical Additives for China National Light Industry, School of Chemistry & Chemical Engineering, Shaanxi University of Science & Technology, Weiyang, University Park, Xi'an, 710021, China
| | - Zhenyu Zhu
- Isotopomics in Chemical Biology (ICB) & Key Laboratory of Chemical Additives for China National Light Industry, School of Chemistry & Chemical Engineering, Shaanxi University of Science & Technology, Weiyang, University Park, Xi'an, 710021, China
| | - Yu Xia
- Isotopomics in Chemical Biology (ICB) & Key Laboratory of Chemical Additives for China National Light Industry, School of Chemistry & Chemical Engineering, Shaanxi University of Science & Technology, Weiyang, University Park, Xi'an, 710021, China
| | - Muyang Zhong
- Isotopomics in Chemical Biology (ICB) & Key Laboratory of Chemical Additives for China National Light Industry, School of Chemistry & Chemical Engineering, Shaanxi University of Science & Technology, Weiyang, University Park, Xi'an, 710021, China
| | - Ran Ma
- Isotopomics in Chemical Biology (ICB) & Key Laboratory of Chemical Additives for China National Light Industry, School of Chemistry & Chemical Engineering, Shaanxi University of Science & Technology, Weiyang, University Park, Xi'an, 710021, China
| | - Yu Zhao
- Isotopomics in Chemical Biology (ICB) & Key Laboratory of Chemical Additives for China National Light Industry, School of Chemistry & Chemical Engineering, Shaanxi University of Science & Technology, Weiyang, University Park, Xi'an, 710021, China
| | - Qiulin Yan
- Isotopomics in Chemical Biology (ICB) & Key Laboratory of Chemical Additives for China National Light Industry, School of Chemistry & Chemical Engineering, Shaanxi University of Science & Technology, Weiyang, University Park, Xi'an, 710021, China
| | - Qing Miao
- Isotopomics in Chemical Biology (ICB) & Key Laboratory of Chemical Additives for China National Light Industry, School of Chemistry & Chemical Engineering, Shaanxi University of Science & Technology, Weiyang, University Park, Xi'an, 710021, China
| | - Bo Wang
- Isotopomics in Chemical Biology (ICB) & Key Laboratory of Chemical Additives for China National Light Industry, School of Chemistry & Chemical Engineering, Shaanxi University of Science & Technology, Weiyang, University Park, Xi'an, 710021, China
| | - Yi Ma
- Isotopomics in Chemical Biology (ICB) & Key Laboratory of Chemical Additives for China National Light Industry, School of Chemistry & Chemical Engineering, Shaanxi University of Science & Technology, Weiyang, University Park, Xi'an, 710021, China
| | - Xijie Yin
- MNR Third Institute of Oceanology, Daxue Rd, Xiamen, 361005, China
| | - Youping Zhou
- Isotopomics in Chemical Biology (ICB) & Key Laboratory of Chemical Additives for China National Light Industry, School of Chemistry & Chemical Engineering, Shaanxi University of Science & Technology, Weiyang, University Park, Xi'an, 710021, China; Southern Marine Science and Engineering Guangdong Laboratory, Zhuhai, 51900, China; International Center for Isotope Effects Research (ICIER), Nanjing University, Nanjing, 210023, China.
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Merino C, Kuzyakov Y, Godoy K, Jofré I, Nájera F, Matus F. Iron-reducing bacteria decompose lignin by electron transfer from soil organic matter. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 761:143194. [PMID: 33183799 DOI: 10.1016/j.scitotenv.2020.143194] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 10/11/2020] [Accepted: 10/17/2020] [Indexed: 06/11/2023]
Abstract
Iron-reducing bacteria (IRB) are crucial for electron transfer in anaerobic soil microsites. The utilization of the energy gathered by this mechanism by decomposers of organic matter is a challenging and fascinating issue. We hypothesized that bacteria reducing Fe(III) (oxyhydr)oxides to soluble Fe(II) obtain electrons from reduced soil organic matter (SOMr) involving lignin oxidation. Iron-reducing bacteria were isolated from topsoils of various climates (humid temperate, cold temperate, subpolar), vegetation types (mostly grasslands and forests), and derived from various parent materials treatments assigned as Granitic, Volcanic-allophanic, Fluvio-glacial, Basaltic-Antarctic and Metamorphic. After the screening of IRB by phospholipid fatty acid (PLFA) analysis and PCR identification (full-length 16S rDNA), the IRB were inoculated to 20 samples (five soils and 4 replicates) and a broad range of parallel processes were traced. Geobacter metallireducens and Geobacter lovleyi were the main Geobacteraceae-strains present in all soils and strongly increased the activity of ligninolytic enzymes: lignin peroxidase and manganese peroxidase. Carbon dioxide (CO2) released from IRB-inoculated soils was 140% higher than that produced by Fenton reactions (induced by H2O2 and Fe(II) addition) but 40% lower than in non-sterile soils. CO2 release was closely correlated with the produced Fe (II) and H2O2 consumption. The highest CO2 was released from Basaltic-Antarctic soils with the highest Fe content and was closely correlated with lignin depolymerization (detection by fluorescence images). All IRB oxidized the lignin contained in the SOM within a wide pH range and in soils from all parent materials. We present a conceptual model showing electron shuttling from SOM containing lignin (as a C and energy source) to IRB to produce energy and promote Fe(III) (oxyhydr)oxides reduction was proposed and discussed.
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Affiliation(s)
- Carolina Merino
- Center of Plant, Soil Interaction and Natural Resources Biotechnology Scientific and Technological Bioresource Nucleus (BIOREN), Temuco, Chile; Laboratory of Conservation and Dynamics of Volcanic Soils, Department of Chemical Sciences and Natural Resources, Universidad de La Frontera, Temuco, Chile; Network for Extreme Environmental Research, Universidad de la Frontera, Temuco, Chile
| | - Yakov Kuzyakov
- Network for Extreme Environmental Research, Universidad de la Frontera, Temuco, Chile; Soil Science of Temperate Ecosystems, Büsgen Institute, Georg-August-Universität Göttingen, Germany; Institute of Environmental Sciences, Kazan Federal University, Kazan, Russia; RUDN, Moscow, Russia
| | - Karina Godoy
- Center of Plant, Soil Interaction and Natural Resources Biotechnology Scientific and Technological Bioresource Nucleus (BIOREN), Temuco, Chile
| | - Ignacio Jofré
- Laboratory of Conservation and Dynamics of Volcanic Soils, Department of Chemical Sciences and Natural Resources, Universidad de La Frontera, Temuco, Chile
| | - Francisco Nájera
- PhD Program in Science of Natural Resource Sciences, Universidad de La Frontera, Chile
| | - Francisco Matus
- Laboratory of Conservation and Dynamics of Volcanic Soils, Department of Chemical Sciences and Natural Resources, Universidad de La Frontera, Temuco, Chile; Network for Extreme Environmental Research, Universidad de la Frontera, Temuco, Chile.
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12
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Merino C, Matus F, Kuzyakov Y, Dyckmans J, Stock S, Dippold MA. Contribution of the Fenton reaction and ligninolytic enzymes to soil organic matter mineralisation under anoxic conditions. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 760:143397. [PMID: 33199010 DOI: 10.1016/j.scitotenv.2020.143397] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 10/26/2020] [Accepted: 10/28/2020] [Indexed: 06/11/2023]
Abstract
Mechanisms of carbon dioxide (CO2) release from soil in the absence of oxygen were studied considering the Fenton process, which encompasses the reaction of H2O2 with Fe(II) yielding a hydroxyl radical (OH), in combination with manganese peroxidase (MnP) and lignin peroxidase (LiP). This study aimed to explain the high rate of soil organic matter (SOM) mineralisation and CO2 release from humid temperate rainforest soils under oxygen-limited conditions. The investigated mechanisms challenge the traditional view that SOM mineralisation in rainforest is slow due to anaerobic (micro)environments under high precipitation and explain intensive CO2 release even under oxygen limitation. We hypothesised that the Fenton reaction (FR) greatly contributes to the CO2 released from SOM mineralised under anaerobic conditions especially in the presence of ligninolytic enzymes. We used a novel technique that combines labelled H218O2 and Fe(II) to induce the FR and measured CO18O, Fe(II) solubilisation, and peroxide consumption in a closed gas circulation system for 6 h. Maximal CO2 amount was released when the FR was induced in combination with LiP addition. The CO2 efflux with LiP was 10-fold that of abiotic FR reactions without enzymes, or in soils amended with MnP. This was consistent with i) the contribution of 18O from peroxide to CO2 release, ii) peroxide consumption, and iii) Fe(II) solubilisation by FR. The amount of consumed peroxide was closely correlated with the CO18O derived from soil without enzyme addition or with LiP addition. Concluding, abiotic Fenton Reaction coupled with oxidative enzymes, such as LiP, are crucial for SOM oxidation under anaerobic conditions, e.g. in temperate rainforest soils.
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Affiliation(s)
- Carolina Merino
- Center of Plant, Soil Interaction and Natural Resources Biotechnology Scientific and Technological Bioresource Nucleus (BIOREN), Temuco, Chile; Laboratory of Conservation and Dynamic of Volcanic Soils, Department of Chemical Sciences and Natural Resources, Universidad de La Frontera, Temuco, Chile; Network for Extreme Environmental Research (NEXER), Universidad de La Frontera, Temuco, Chile.
| | - Francisco Matus
- Laboratory of Conservation and Dynamic of Volcanic Soils, Department of Chemical Sciences and Natural Resources, Universidad de La Frontera, Temuco, Chile; Network for Extreme Environmental Research (NEXER), Universidad de La Frontera, Temuco, Chile
| | - Yakov Kuzyakov
- Division of Agricultural Soil Science, University of Gottingen, Gottingen, Germany; Institute of Environmental Sciences, Kazan Federal University, 420049 Kazan, Russia; Agro-Technology Institute, RUDN University, 117198 Moscow, Russia
| | - Jens Dyckmans
- Centre for Stable Isotope Research and Analysis, University of Gottingen, Gottingen, Germany
| | - Svenja Stock
- Biogeochemistry of Agroecosystems, University of Gottingen, Gottingen, Germany
| | - Michaela A Dippold
- Biogeochemistry of Agroecosystems, University of Gottingen, Gottingen, Germany
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13
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Gutiérrez del Arroyo O, Wood TE. Large seasonal variation of soil respiration in a secondary tropical moist forest in Puerto Rico. Ecol Evol 2021; 11:263-272. [PMID: 33437428 PMCID: PMC7790624 DOI: 10.1002/ece3.7021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Accepted: 10/16/2020] [Indexed: 11/08/2022] Open
Abstract
Tropical forests are the largest contributors to global emissions of carbon dioxide (CO2) to the atmosphere via soil respiration (R s). As such, identifying the main controls on R s in tropical forests is essential for accurately projecting the consequences of ongoing and future global environmental changes to the global C cycle. We measured hourly R s in a secondary tropical moist forest in Puerto Rico over a 3-year period to (a) quantify the magnitude of R s and (b) identify the role of climatic, substrate, and nutrient controls on the seasonality of R s. Across 3 years of measurements, mean R s was 7.16 ± 0.02 μmol CO2 m-2 s-1 (or 2,710 g C m-2 year-1) and showed significant seasonal variation. Despite small month-to-month variation in temperature (~4°C), we found significant positive relationships between daily and monthly R s with both air and soil temperature, highlighting the importance of temperature as a driver of R s even in warm ecosystems, such as tropical forests. We also found a significant parabolic relationship between mean daily volumetric soil moisture and mean daily R s, with an optimal moisture value of 0.34 m3 m-3. Given the relatively consistent climate at this site, the large range in mean monthly R s (~7 μmol CO2 m-2 s-1) was surprising and suggests that even small changes in climate can have large implications for ecosystem respiration. The strong positive relationship of R s with temperature at monthly timescales particularly stands out, as moisture is usually considered a stronger control of R s in tropical forests that already experience warm temperatures year-round. Moreover, our results revealed the strong seasonality of R s in tropical moist forests, which given its high magnitude, can represent a significant contribution to the seasonal patterns of atmospheric (CO2) globally.
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Affiliation(s)
- Omar Gutiérrez del Arroyo
- Department of BiologyUniversity of Puerto RicoRío PiedrasPuerto Rico
- USDA Forest Service International Institute of Tropical ForestryRio PiedrasPuerto Rico
- Department of Environmental Science, Policy, and ManagementUniversity of CaliforniaBerkeleyCalifornia
| | - Tana E. Wood
- USDA Forest Service International Institute of Tropical ForestryRio PiedrasPuerto Rico
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14
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Zeng Q, Wang X, Liu X, Huang L, Hu J, Chu R, Tolic N, Dong H. Mutual Interactions between Reduced Fe-Bearing Clay Minerals and Humic Acids under Dark, Oxygenated Conditions: Hydroxyl Radical Generation and Humic Acid Transformation. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:15013-15023. [PMID: 32991154 DOI: 10.1021/acs.est.0c04463] [Citation(s) in RCA: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Hydroxyl radicals (·OH) exert a strong impact on the carbon cycle due to their nonselective and highly oxidizing nature. Reduced iron-containing clay minerals (RIC) are one of the major contributors to the formation of ·OH in dark environments, but their interactions with humic acids (HA) are poorly known. Here, we investigate the mutual interactions between RIC and HA under dark and oxygenated conditions. HA decreased the oxidation rate of structural Fe(II) in RIC but significantly promoted the ·OH yield. HA dissolved a fraction of Fe(II) from RIC to form an aqueous Fe(II)-HA complex. ·OH were generated through both heterogeneous (through oxidation of structural Fe(II)) and homogeneous pathways (through oxidation of aqueous Fe(II)-HA species). RIC-mediated ·OH production by providing H2O2 to react with Fe(II)-HA and electrons to regenerate Fe(II)-HA. This highly efficient homogeneous pathway was responsible for increased ·OH yield. Abundant ·OH significantly decreased the molecular size, bleached chromophores, and increased the oxygen-containing functional groups of HA. These molecular changes of HA resembled photochemical transformation of HA. The mutual interaction between RIC and HA in dark and redox-fluctuating environments provides a new pathway for fast turnover of recalcitrant organic matters in clay- and HA-rich ecosystems such as tropical forest soils and tidal marsh sediments.
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Affiliation(s)
- Qiang Zeng
- Center for Geomicrobiology and Biogeochemistry Research, State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing 100083, China
- School of Earth Sciences and Resources, China University of Geosciences, Beijing 100083, China
| | - Xi Wang
- Center for Geomicrobiology and Biogeochemistry Research, State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing 100083, China
- School of Earth Sciences and Resources, China University of Geosciences, Beijing 100083, China
| | - Xiaolei Liu
- Center for Geomicrobiology and Biogeochemistry Research, State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing 100083, China
- School of Water Resources and Environment, China University of Geosciences, Beijing 100083, China
| | - Liuqin Huang
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan 430074, China
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Jinglong Hu
- Center for Geomicrobiology and Biogeochemistry Research, State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing 100083, China
- School of Earth Sciences and Resources, China University of Geosciences, Beijing 100083, China
| | - Rosalie Chu
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Nikola Tolic
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Hailiang Dong
- Center for Geomicrobiology and Biogeochemistry Research, State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing 100083, China
- School of Earth Sciences and Resources, China University of Geosciences, Beijing 100083, China
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15
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Yu G, Zhao H, Chen J, Zhang T, Cai Z, Zhou G, Li Z, Qiu Z, Wu Z. Soil microbial community dynamics mediate the priming effects caused by in situ decomposition of fresh plant residues. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 737:139708. [PMID: 32474301 DOI: 10.1016/j.scitotenv.2020.139708] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 05/19/2020] [Accepted: 05/23/2020] [Indexed: 06/11/2023]
Abstract
Extreme climate events always leave numerous fresh plant materials (FOM) in forests, thus increasing the input of carbon (C) resources to soil system. The input of exogenous C may accelerate or inhibit the decomposition of soil organic carbon (SOC), which is defined as the positive or negative priming effect (PE), respectively. However, the characteristics and microbial mechanisms of PE caused by FOM remain unknown. A 110-day in situ soil incubation experiment was conducted in a subtropical forest, with 13C-labeled fresh leaves from four native species (Castanopsis fissa, CF; Pinus massoniana, PM; Machilus chekiangensis, MC; and Castanopsis chinensis, CC) serving as the FOM respectively. We measured the CO2 effluxes derived from 13C-labeled FOM and soil, and the composition and diversity of soil bacterial and fungal communities throughout the incubation to explore the correlations between PE and microbial attributes. As a result, the PE caused by FOM inputs were negative initially but became positive after 61 d. The FOM decomposition rate was positively related to PE intensity, and there was a significant difference between coniferous and broadleaved species in the middle period of the study. More than 77% of the total C lost from FOM was emitted as CO2, indicating that FOM-C serves as an energy resource for soil microbes. The α-diversity of the bacterial community at genus-level showed significantly positive correlation with PE at 24 d, and the composition of bacterial community at OTU-level had a marked relationship with the PE between 24-110 d. The relationship between fungal community diversity and composition with PE was only observed at 7 and 110 d, respectively. This study firstly investigated the patterns of PE resulted from numerous FOM input, and the results suggested that soil bacterial community, in particular the Actinobacteria phyla, played a more important role in triggering such PEs than fungal community.
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Affiliation(s)
- Guangcan Yu
- Research Institute of Tropical Forestry, Chinese Academy of Forestry, Longdong, Guangzhou 510520, PR China
| | - Houben Zhao
- Research Institute of Tropical Forestry, Chinese Academy of Forestry, Longdong, Guangzhou 510520, PR China
| | - Jie Chen
- Research Institute of Tropical Forestry, Chinese Academy of Forestry, Longdong, Guangzhou 510520, PR China
| | - Tianlin Zhang
- Research Institute of Tropical Forestry, Chinese Academy of Forestry, Longdong, Guangzhou 510520, PR China
| | - Zhanglin Cai
- Research Institute of Tropical Forestry, Chinese Academy of Forestry, Longdong, Guangzhou 510520, PR China
| | - Guangyi Zhou
- Research Institute of Tropical Forestry, Chinese Academy of Forestry, Longdong, Guangzhou 510520, PR China
| | - Zhaojia Li
- Research Institute of Tropical Forestry, Chinese Academy of Forestry, Longdong, Guangzhou 510520, PR China
| | - Zhijun Qiu
- Research Institute of Tropical Forestry, Chinese Academy of Forestry, Longdong, Guangzhou 510520, PR China
| | - Zhongmin Wu
- Research Institute of Tropical Forestry, Chinese Academy of Forestry, Longdong, Guangzhou 510520, PR China.
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16
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Synergy effect of peroxidase enzymes and Fenton reactions greatly increase the anaerobic oxidation of soil organic matter. Sci Rep 2020; 10:11289. [PMID: 32647197 PMCID: PMC7347925 DOI: 10.1038/s41598-020-67953-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Accepted: 06/15/2020] [Indexed: 11/22/2022] Open
Abstract
In temperate rainforest soils of southern Chile (38 °S), there are high rates of soil organic carbon (SOC) mineralization under oxygen (O2) limitation. We study the combined effects of Fenton reactions and the activity of two enzymes manganese peroxidase (MnP) and lignin peroxidase (LiP), which was hypothesised potentiate SOC mineralization under anoxic conditions leading to carbon dioxide (CO2) release. Both mechanisms produce free radicals when competing for SOC oxidation in the absence of microorganisms. We quantify the CO2 release by induced Fenton reactions in combination with MnP and LiP under aerobic and anaerobic conditions (20 °C, 36 h) in temperate rainforest soils. CO2 levels released by Fenton reactions and enzyme activity were eight times higher than those released by Fenton reaction and peroxidase enzymes in individual treatment. Approximately 31% of the CO2 released under aerobic soil incubation was found to be abiotic (sterilized), while 69% was biotic (non-sterilized soils), and respective values of 17% and 83% were recorded under anaerobic conditions. The relative fluorescence intensity clearly shows ·OH radicals production from Fenton reactions. In conclusion, levels of MnP and LiP coupled with Fenton reactions strongly increase SOC mineralization under long periods of O2 limitation in temperate rainforest soils.
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17
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Hall SJ, Huang W, Timokhin VI, Hammel KE. Lignin lags, leads, or limits the decomposition of litter and soil organic carbon. Ecology 2020; 101:e03113. [PMID: 32506475 DOI: 10.1002/ecy.3113] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Revised: 05/11/2020] [Accepted: 05/22/2020] [Indexed: 11/07/2022]
Abstract
Lignin's role in litter and soil organic carbon (SOC) decomposition remains contentious. Lignin decomposition was traditionally thought to increase during midstage litter decomposition, when cellulose occlusion by lignin began to limit mass loss. Alternatively, lignin decomposition could be greatest in fresh litter as a consequence of co-metabolism, and lignin might decompose faster than bulk SOC. To test these competing hypotheses, we incubated 10 forest soils with C4 grass litter (amended with 13 C-labeled or unlabeled lignin) over 2 yr and measured soil respiration and its isotope composition. Early lignin decomposition was greatest in 5 of 10 soils, consistent with the co-metabolism hypothesis. However, lignin decomposition peaked 6-24 months later in the other five soils, consistent with the substrate-limitation hypothesis; these soils were highly acidic. Rates of lignin, litter, and SOC decomposition tended to converge over time. Cumulative lignin decomposition was never greater than SOC decomposition; lignin decomposition was significantly lower than SOC decomposition in six soils. Net nitrogen mineralization predicted lignin decomposition ratios relative to litter and SOC. Although the onset of lignin decomposition can indeed be rapid, lignin still presents a likely bottleneck in litter and SOC decomposition, meriting a reconsideration of lignin's role in modern decomposition paradigms.
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Affiliation(s)
- Steven J Hall
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, Iowa, 50011, USA
| | - Wenjuan Huang
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, Iowa, 50011, USA
| | - Vitaliy I Timokhin
- Department of Energy Great Lakes Bioenergy Research Center, Wisconsin Energy Institute, University of Wisconsin, Madison, Wisconsin, 53706, USA
| | - Kenneth E Hammel
- U.S. Forest Products Laboratory, Madison, Wisconsin, 53726, USA.,Department of Bacteriology, University of Wisconsin, Madison, Wisconsin, 53706, USA
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18
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Chang Z, Tian L, Li F, Wu M, Steinberg CEW, Pan B, Xing B. Organo-mineral complexes protect condensed organic matter as revealed by benzene-polycarboxylic acids. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2020; 260:113977. [PMID: 31991352 DOI: 10.1016/j.envpol.2020.113977] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 12/18/2019] [Accepted: 01/11/2020] [Indexed: 06/10/2023]
Abstract
Condensed organic matters (COM) with black carbon-like structures are considered as long-term carbon sinks because of their high stability. It is difficult to distinguish COM from general organic matter by conventional chemical analysis, thus the contribution by and interaction mechanisms of organo-mineral complexes in COM stabilization are unclear and generally neglected. Molecular markers related to black carbon-like structures, such as benzene polycarboxylic acids (BPCAs), are promising tools for the qualitative and quantitative analysis of COM. In this study, one natural soil and two cultivated soils with 25 y- or 55 y-tillage activities were collected and the distribution characteristics of BPCAs were detected. All the investigated soils showed similar BPCA distribution pattern, and over 60% of BPCAs were detected in clay fraction. The extractable BPCA contents were substantially increased after mineral removal. The ratios of BPCA contents before and after mineral removal indicate the extent of COM-mineral particle interactions, and our results suggested that up to 73% COM were protected by mineral particles, and more stronger interactions were noted on clay than on silt. The initial cultivation dramatically decreased COM-clay interactions, and this interaction was recovered only slowly after 55-y cultivation. Kaolinite and muscovite are important for COM protection. But a possible negative correlation between BPCAs and reactive iron oxides of the cultivated soils suggested that iron may promote COM degradation when disturbed by tillage activities. This study provided a new angle to study the stabilization of COM and emphasized the importance of organo-mineral complexes for COM stabilization.
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Affiliation(s)
- Zhaofeng Chang
- Faculty of Environmental Science & Engineering, Kunming University of Science & Technology, Kunming, 650500, China; Yunnan Provincial Key Laboratory of Soil Carbon Sequestration and Pollution Control, Kunming, Yunnan, 650500, China; Stockbridge School of Agriculture, University of Massachusetts, Amherst, MA, 01003, United States
| | - Luping Tian
- Faculty of Environmental Science & Engineering, Kunming University of Science & Technology, Kunming, 650500, China; Yunnan Institute of Environmental Science, Kunming, 650500, China
| | - Fangfang Li
- Faculty of Environmental Science & Engineering, Kunming University of Science & Technology, Kunming, 650500, China; Yunnan Provincial Key Laboratory of Soil Carbon Sequestration and Pollution Control, Kunming, Yunnan, 650500, China
| | - Min Wu
- Faculty of Environmental Science & Engineering, Kunming University of Science & Technology, Kunming, 650500, China; Yunnan Provincial Key Laboratory of Soil Carbon Sequestration and Pollution Control, Kunming, Yunnan, 650500, China
| | - Christian E W Steinberg
- Humboldt-Universität zu Berlin, Laboratory of Freshwater & Stress Ecology, Arboretum, Späthstr. 80/81, 12437, Berlin, Germany
| | - Bo Pan
- Faculty of Environmental Science & Engineering, Kunming University of Science & Technology, Kunming, 650500, China; Yunnan Provincial Key Laboratory of Soil Carbon Sequestration and Pollution Control, Kunming, Yunnan, 650500, China.
| | - Baoshan Xing
- Stockbridge School of Agriculture, University of Massachusetts, Amherst, MA, 01003, United States
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19
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Sarker TC, Maisto G, De Marco A, Memoli V, Panico SC, Motti R, Idbella M, Incerti G, Mazzoleni S, Bonanomi G. Species‐specific root proliferation of tree seedlings in tropical litter: do nutrients matter? OIKOS 2020. [DOI: 10.1111/oik.06786] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- Tushar C. Sarker
- Dept of Agricultural Science, Univ. of Naples Federico II via Università 100 IT‐80055 Portici (NA) Italy
- School of Environmental and Resource Sciences, Zhejiang A&F Univ. Lin'an PR China
| | - Giulia Maisto
- Dept of Biology, Univ. of Naples Federico II Napoli Italy
| | - Anna De Marco
- Dept of Biology, Univ. of Naples Federico II Napoli Italy
| | - Valeria Memoli
- Dept of Biology, Univ. of Naples Federico II Napoli Italy
| | | | - Riccardo Motti
- Dept of Agricultural Science, Univ. of Naples Federico II via Università 100 IT‐80055 Portici (NA) Italy
| | - Mohamed Idbella
- Dept of Agricultural Science, Univ. of Naples Federico II via Università 100 IT‐80055 Portici (NA) Italy
| | - Guido Incerti
- Di4A, Dept of Agri‐Food, Animal and Environmental Sciences, Univ. of Udine Udine Italy
| | - Stefano Mazzoleni
- Dept of Agricultural Science, Univ. of Naples Federico II via Università 100 IT‐80055 Portici (NA) Italy
| | - Giuliano Bonanomi
- Dept of Agricultural Science, Univ. of Naples Federico II via Università 100 IT‐80055 Portici (NA) Italy
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20
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Gross A, Lin Y, Weber PK, Pett‐Ridge J, Silver WL. The role of soil redox conditions in microbial phosphorus cycling in humid tropical forests. Ecology 2019; 101:e02928. [DOI: 10.1002/ecy.2928] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Revised: 07/16/2019] [Accepted: 09/25/2019] [Indexed: 11/10/2022]
Affiliation(s)
- Avner Gross
- Department of Environmental Science, Policy, & Management University of California Berkeley Berkeley California 94720 USA
- Department of Geography and Environmental Development Ben Gurion University of the Negev Beer Sheva Israel
| | - Yang Lin
- Department of Environmental Science, Policy, & Management University of California Berkeley Berkeley California 94720 USA
| | - Peter K. Weber
- Lawrence Livermore National Laboratory Physical and Life Science Directorate Livermore California 94550 USA
| | - Jennifer Pett‐Ridge
- Lawrence Livermore National Laboratory Physical and Life Science Directorate Livermore California 94550 USA
| | - Whendee L. Silver
- Department of Environmental Science, Policy, & Management University of California Berkeley Berkeley California 94720 USA
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21
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Huang W, Hammel KE, Hao J, Thompson A, Timokhin VI, Hall SJ. Enrichment of Lignin-Derived Carbon in Mineral-Associated Soil Organic Matter. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:7522-7531. [PMID: 31177774 DOI: 10.1021/acs.est.9b01834] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
A modern paradigm of soil organic matter proposes that persistent carbon (C) derives primarily from microbial residues interacting with minerals, challenging older ideas that lignin moieties contribute to soil C because of inherent recalcitrance. We proposed that aspects of these old and new paradigms can be partially reconciled by considering interactions between lignin decomposition products and redox-sensitive iron (Fe) minerals. An Fe-rich tropical soil (with C4 litter and either 13C-labeled or unlabeled lignin) was pretreated with different durations of anaerobiosis (0-12 days) and incubated aerobically for 317 days. Only 5.7 ± 0.2% of lignin 13C was mineralized to CO2 versus 51.2 ± 0.4% of litter C. More added lignin-derived C (48.2 ± 0.9%) than bulk litter-derived C (30.6 ± 0.7%) was retained in mineral-associated organic matter (MAOM; density >1.8 g cm-3), and 12.2 ± 0.3% of lignin-derived C vs 6.4 ± 0.1% of litter C accrued in clay-sized (<2 μm) MAOM. Longer anaerobic pretreatments increased added lignin-derived C associated with Fe, according to extractions and nanoscale secondary ion mass spectrometry (NanoSIMS). Microbial residues are important, but lignin-derived C may also contribute disproportionately to MAOM relative to bulk litter-derived C, especially following redox-sensitive biogeochemical interactions.
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Affiliation(s)
- Wenjuan Huang
- Department of Ecology, Evolution, and Organismal Biology , Iowa State University , Ames , Iowa 50011 , United States
- Key laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden , Chinese Academy of Sciences , Guangzhou 510650 , China
| | - Kenneth E Hammel
- US Forest Products Laboratory , Madison , Wisconsin 53726 , United States
- Department of Bacteriology , University of Wisconsin , Madison , Wisconsin 53706 , United States
| | - Jialong Hao
- Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics , Chinese Academy of Sciences , Beijing 100029 , China
| | - Aaron Thompson
- Department of Crop and Soil Sciences , The University of Georgia , Athens , Georgia 30602 , United States
| | - Vitaliy I Timokhin
- University of Wisconsin , Wisconsin Energy Institute, DOE Great Lakes Bioenergy Research Center , Madison , Wisconsin 53706 , United States
| | - Steven J Hall
- Department of Ecology, Evolution, and Organismal Biology , Iowa State University , Ames , Iowa 50011 , United States
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22
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Chao L, Liu Y, Freschet GT, Zhang W, Yu X, Zheng W, Guan X, Yang Q, Chen L, Dijkstra FA, Wang S. Litter carbon and nutrient chemistry control the magnitude of soil priming effect. Funct Ecol 2019. [DOI: 10.1111/1365-2435.13278] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Lin Chao
- Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology Chinese Academy of Sciences Shenyang China
- University of Chinese Academy of Sciences Beijing China
| | - Yanyan Liu
- Key Laboratory of Environment Change and Resources Use in Beibu Gulf, Ministry of Education Guangxi Teachers Education University Nanning China
| | - Grégoire T. Freschet
- Centre d’Ecologie Fonctionnelle et Evolutive (CNRS—Université de Montpellier—Université Paul Valéry Montpellier—EPHE—IRD) Montpellier France
| | - Weidong Zhang
- Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology Chinese Academy of Sciences Shenyang China
- Huitong Experimental Station of Forest Ecology Chinese Academy of Sciences Huitong China
| | - Xin Yu
- Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology Chinese Academy of Sciences Shenyang China
- University of Chinese Academy of Sciences Beijing China
| | - Wenhui Zheng
- Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology Chinese Academy of Sciences Shenyang China
- University of Chinese Academy of Sciences Beijing China
| | - Xin Guan
- Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology Chinese Academy of Sciences Shenyang China
- Huitong Experimental Station of Forest Ecology Chinese Academy of Sciences Huitong China
| | - Qingpeng Yang
- Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology Chinese Academy of Sciences Shenyang China
- Huitong Experimental Station of Forest Ecology Chinese Academy of Sciences Huitong China
| | - Longchi Chen
- Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology Chinese Academy of Sciences Shenyang China
- Huitong Experimental Station of Forest Ecology Chinese Academy of Sciences Huitong China
| | - Feike A. Dijkstra
- Sydney Institute of Agriculture, School of Life and Environmental Sciences The University of Sydney Camden New South Wales Australia
| | - Silong Wang
- Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology Chinese Academy of Sciences Shenyang China
- Huitong Experimental Station of Forest Ecology Chinese Academy of Sciences Huitong China
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23
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Bhattacharyya A, Campbell AN, Tfaily MM, Lin Y, Kukkadapu RK, Silver WL, Nico PS, Pett-Ridge J. Redox Fluctuations Control the Coupled Cycling of Iron and Carbon in Tropical Forest Soils. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:14129-14139. [PMID: 30451506 DOI: 10.1021/acs.est.8b03408] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Oscillating redox conditions are a common feature of humid tropical forest soils, driven by an ample supply and dynamics of reductants, high moisture, microbial oxygen consumption, and finely textured clays that limit diffusion. However, the net result of variable soil redox regimes on iron (Fe) mineral dynamics and associated carbon (C) forms and fluxes is poorly understood in tropical soils. Using a 44-day redox incubation experiment with humid tropical forest soils from Puerto Rico, we examined patterns in Fe and C transformations under four redox regimes: static anoxic, "flux 4-day" (4d oxic, 4d anoxic), "flux 8-day" (8d oxic, 4d anoxic) and static oxic. Prolonged anoxia promoted reductive dissolution of Fe-oxides, and led to an increase in soluble Fe(II) and amorphous Fe oxide pools. Preferential dissolution of the less-crystalline Fe pool was evident immediately following a shift in bulk redox status (oxic to anoxic), and coincided with increased dissolved organic C, presumably due to acidification or direct release of organic matter (OM) from dissolving Fe(III) mineral phases. The average nominal oxidation state of water-soluble C was lowest under persistent anoxic conditions, suggesting that more reduced organic compounds were metabolically unavailable for microbial consumption under reducing conditions. Anoxic soil compounds had high H/C values (and were similar to lignin-like compounds) whereas oxic soil compounds had higher O/C values, akin to tannin- and cellulose-like components. Cumulative respiration derived from native soil organic C was highest in static oxic soils. These results show how Fe minerals and Fe-OM interactions in tropical soils are highly sensitive to variable redox effects. Shifting soil oxygen availability rapidly impacted exchanges between mineral-sorbed and aqueous C pools, increased the dissolved organic C pool under anoxic conditions implying that the periodicity of low-redox events may control the fate of C in wet tropical soils.
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Affiliation(s)
- Amrita Bhattacharyya
- Earth and Environmental Sciences Area, Lawrence Berkeley National Laboratory , 1 Cyclotron Road , Berkeley , California 94720 , United States
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory , 7000 East Avenue , Livermore , California 94550 , United States
| | - Ashley N Campbell
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory , 7000 East Avenue , Livermore , California 94550 , United States
| | - Malak M Tfaily
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory , Richland , Washington 99354 , United States
| | - Yang Lin
- Department of Environmental Science, Policy, and Management , University of California, Berkeley , Berkeley , California 94720 , United States
| | - Ravi K Kukkadapu
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory , Richland , Washington 99354 , United States
| | - Whendee L Silver
- Department of Environmental Science, Policy, and Management , University of California, Berkeley , Berkeley , California 94720 , United States
| | - Peter S Nico
- Earth and Environmental Sciences Area, Lawrence Berkeley National Laboratory , 1 Cyclotron Road , Berkeley , California 94720 , United States
| | - Jennifer Pett-Ridge
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory , 7000 East Avenue , Livermore , California 94550 , United States
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24
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Soil Oxygen Limits Microbial Phosphorus Utilization in Humid Tropical Forest Soils. SOIL SYSTEMS 2018. [DOI: 10.3390/soilsystems2040065] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Soil phosphorus (P) availability is of special interest in many humid tropical forests, especially those on highly weathered, iron (Fe)- and aluminum (Al)-rich soils where P often limits net primary productivity. Phosphorus cycling is partly dependent on the ability of microbes to compete for P with Fe and Al minerals, which strongly bind P. Soil P availability is also indirectly affected by soil redox conditions due to its effects on microbial activity and reductive dissolution of Fe oxides that may weaken Fe-O-P sorption strength. Here, we explored P sorption, soil Fe (II) concentrations, soil CO2 production, organic and inorganic P pools, and microbial biomass P in tropical soils that typically experience frequent low redox (valley soils), or fluctuating redox conditions (slope soils). Soils from both topographic positions were pre-incubated under oxic or anoxic headspaces and then amended with a mixture of P (as orthophosphate) and carbon (C, as acetate, to maintain microbial activity) and incubated in the dark for 24 h. Phosphorus sorption to the mineral phase occurred on a time scale of seconds to minutes in valley and slope soils, reflecting strong abiotic P sorption capacity. Valley soils were characterized by inherently higher Fe(II) concentrations and lower respiration rates. Under anoxic headspaces, Fe(II) concentrations increased 3-to 5-fold in the both soils. Soil respiration and microbial P utilization declined significantly in both soils under anoxic conditions, regardless of Fe(II) concentrations. Microbial P concentrations were highest when slope soils were incubated under an oxic headspace, despite the high P sorption under these conditions. Our results suggest that microbial P utilization is indirectly limited by low O2 availability and that microbes are able to effectively compete with minerals for P under Fe-oxidizing conditions. These results emphasize the central role of soil microorganisms in regulating P availability, even in the presence of strong abiotic sorption capacity.
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25
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Wilhelm RC, Singh R, Eltis LD, Mohn WW. Bacterial contributions to delignification and lignocellulose degradation in forest soils with metagenomic and quantitative stable isotope probing. ISME JOURNAL 2018; 13:413-429. [PMID: 30258172 PMCID: PMC6331573 DOI: 10.1038/s41396-018-0279-6] [Citation(s) in RCA: 153] [Impact Index Per Article: 25.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Revised: 05/20/2018] [Accepted: 08/11/2018] [Indexed: 11/19/2022]
Abstract
Delignification, or lignin-modification, facilitates the decomposition of lignocellulose in woody plant biomass. The extant diversity of lignin-degrading bacteria and fungi is underestimated by culture-dependent methods, limiting our understanding of the functional and ecological traits of decomposers populations. Here, we describe the use of stable isotope probing (SIP) coupled with amplicon and shotgun metagenomics to identify and characterize the functional attributes of lignin, cellulose and hemicellulose-degrading fungi and bacteria in coniferous forest soils from across North America. We tested the extent to which catabolic genes partitioned among different decomposer taxa; the relative roles of bacteria and fungi, and whether taxa or catabolic genes correlated with variation in lignocellulolytic activity, measured as the total assimilation of 13C-label into DNA and phospholipid fatty acids. We found high overall bacterial degradation of our model lignin substrate, particularly by gram-negative bacteria (Comamonadaceae and Caulobacteraceae), while fungi were more prominent in cellulose-degradation. Very few taxa incorporated 13C-label from more than one lignocellulosic polymer, suggesting specialization among decomposers. Collectively, members of Caulobacteraceae could degrade all three lignocellulosic polymers, providing new evidence for their importance in lignocellulose degradation. Variation in lignin-degrading activity was better explained by microbial community properties, such as catabolic gene content and community structure, than cellulose-degrading activity. SIP significantly improved shotgun metagenome assembly resulting in the recovery of several high-quality draft metagenome-assembled genomes and over 7500 contigs containing unique clusters of carbohydrate-active genes. These results improve understanding of which organisms, conditions and corresponding functional genes contribute to lignocellulose decomposition.
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Affiliation(s)
- Roland C Wilhelm
- Department of Microbiology & Immunology, Life Sciences Institute, University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - Rahul Singh
- Department of Microbiology & Immunology, Life Sciences Institute, University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - Lindsay D Eltis
- Department of Microbiology & Immunology, Life Sciences Institute, University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - William W Mohn
- Department of Microbiology & Immunology, Life Sciences Institute, University of British Columbia, Vancouver, BC, V6T 1Z3, Canada.
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26
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Hall SJ, Huang W, Hammel KE. An optical method for carbon dioxide isotopes and mole fractions in small gas samples: Tracing microbial respiration from soil, litter, and lignin. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2017; 31:1938-1946. [PMID: 28851092 DOI: 10.1002/rcm.7973] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Revised: 08/21/2017] [Accepted: 08/23/2017] [Indexed: 06/07/2023]
Abstract
RATIONALE Carbon dioxide isotope (δ13 C value) measurements enable quantification of the sources of soil microbial respiration, thus informing ecosystem C dynamics. Tunable diode lasers (TDLs) can precisely measure CO2 isotopes at low cost and high throughput, but are seldom used for small samples (≤5 mL). We developed a TDL method for CO2 mole fraction ([CO2 ]) and δ13 C analysis of soil microcosms. METHODS Peaks in infrared absorbance following constant volume sample injection to a carrier were used to independently measure [12 CO2 ] and [13 CO2 ] for subsequent calculation of δ13 C values. Using parallel soil incubations receiving differing C substrates, we partitioned respiration from three sources using mixing models: native soil organic matter (SOM), added litter, and synthetic lignin containing a 13 C label at Cβ of the propyl side chain. RESULTS Once-daily TDL calibration enabled accurate quantification of δ13 C values and [CO2 ] compared with isotope ratio mass spectrometry (IRMS), with long-term external precision of 0.17 and 0.31‰ for 5 and 1 mL samples, respectively, and linear response between 400 and 5000 μmol mol-1 CO2 . Production of CO2 from native soil C, added litter, and lignin Cβ varied over four orders of magnitude. Multiple-pool first-order decay models fitted to data (R2 > 0.98) indicated substantially slower turnover for lignin Cβ (17 years) than for the dominant pool of litter (1.3 years) and primed soil C (3.9 years). CONCLUSIONS Our TDL method provides a flexible, precise, and high-throughput (60 samples h-1 ) alternative to IRMS for small samples. This enables the use of C isotopes in increasingly sophisticated experiments to test biogeochemical controversies, such as the fate of lignins in soil.
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Affiliation(s)
- Steven J Hall
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, 251 Bessey Hall, Ames, IA, 50011, USA
| | - Wenjuan Huang
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, 251 Bessey Hall, Ames, IA, 50011, USA
| | - Kenneth E Hammel
- US Forest Products Laboratory, Madison, WI, 53726, USA
- Department of Bacteriology, University of Wisconsin, Madison, WI, 53706, USA
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