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He T, Lin W, Yang S, Du J, Giri B, Feng C, Gilliam FS, Zhang F, Zhang X, Zhang X. Arbuscular mycorrhizal fungi reduce soil N 2O emissions by altering root traits and soil denitrifier community composition. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 933:173065. [PMID: 38723969 DOI: 10.1016/j.scitotenv.2024.173065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Revised: 04/23/2024] [Accepted: 05/06/2024] [Indexed: 05/20/2024]
Abstract
Arbuscular mycorrhizal fungi (AMF) increase the ability of plants to obtain nitrogen (N) from the soil, and thus can affect emissions of nitrous oxide (N2O), a long-lived potent greenhouse gas. However, the mechanisms underlying the effects of AMF on N2O emissions are still poorly understood, particularly in agroecosystems with different forms of N fertilizer inputs. Utilizing a mesocosm experiment in field, we examined the effects of AMF on N2O emissions via their influence on maize root traits and denitrifying microorganisms under ammonia and nitrate fertilizer input using 15N isotope tracer. Here we show that the presence of AMF alone or both maize roots and AMF increased maize biomass and their 15N uptake, root length, root surface area, and root volume, but led to a reduction in N2O emissions under both N input forms. Random forest model showed that root length and surface area were the most important predictors of N2O emissions. Additionally, the presence of AMF reduced the (nirK + nirS)/nosZ ratio by increasing the relative abundance of nirS-Bradyrhizobium and Rubrivivax with ammonia input, but reducing nosZ-Azospirillum, Cupriavidus and Rhodopseudomonas under both fertilizer input. Further, N2O emissions were significantly and positively correlated with the nosZ-type Azospirillum, Cupriavidus and Rhodopseudomonas, but negatively correlated with the nirS-type Bradyrhizobium and Rubrivivax. These results indicate that AMF reduce N2O emissions by increasing root length to explore N nutrients and altering the community composition of denitrifiers, suggesting that effective management of N fertilizer forms interacting with the rhizosphere microbiome may help mitigate N2O emissions under future N input scenarios.
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Affiliation(s)
- Tangqing He
- College of Agronomy, Henan Agricultural University, Co-construction State Key, Laboratory of Wheat and Maize Crop Science, Zhengzhou 450046, PR China
| | - Wei Lin
- College of Forestry, Fujian Agriculture and Forestry University, Fuzhou 350002, PR China
| | - Shuo Yang
- College of Agronomy, Henan Agricultural University, Co-construction State Key, Laboratory of Wheat and Maize Crop Science, Zhengzhou 450046, PR China
| | - Jiaqi Du
- College of Agronomy, Henan Agricultural University, Co-construction State Key, Laboratory of Wheat and Maize Crop Science, Zhengzhou 450046, PR China
| | - Bhoopander Giri
- Department of Botany, Swami Shraddhanand College, University of Delhi, Delhi, India
| | - Cheng Feng
- College of Agronomy, Henan Agricultural University, Co-construction State Key, Laboratory of Wheat and Maize Crop Science, Zhengzhou 450046, PR China
| | - Frank S Gilliam
- Department of Earth and Environmental Sciences, University of West Florida, Pensacola FL32514, USA
| | - Fuliang Zhang
- College of Agronomy, Henan Agricultural University, Co-construction State Key, Laboratory of Wheat and Maize Crop Science, Zhengzhou 450046, PR China
| | - Xiaoquan Zhang
- College of Tobacco Science, Henan Agricultural University, Zhengzhou 450046, PR China.
| | - Xuelin Zhang
- College of Agronomy, Henan Agricultural University, Co-construction State Key, Laboratory of Wheat and Maize Crop Science, Zhengzhou 450046, PR China.
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He R, Hu S, Li Q, Zhao D, Wu QL, Zeng J. Greater transmission capacities and small-world characteristics of bacterial communities in the above- than those in the below- ground niches of a typical submerged macrophyte, Vallisneria natans. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 903:166229. [PMID: 37586539 DOI: 10.1016/j.scitotenv.2023.166229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 08/06/2023] [Accepted: 08/09/2023] [Indexed: 08/18/2023]
Abstract
Leaves and roots of submerged macrophytes provide extended surfaces and stable internal tissues for distinct microorganisms to rest, but how these microorganisms interact with each other across different niches and ultimately drive the distribution through horizontal and vertical transmissions remains largely undetermined. Knowledge of the mechanisms of assemblage and transmission in aquatic macrophytes-associated microbial communities will help to better understanding their important roles in plant fitness and benefit ecological functions. Here, we conducted a microcosmic experiment based on in situ lake samples to investigate the bacterial community assemblage, transmission, and co-occurrence patterns in different niches of a typical submerged macrophyte, Vallisneria natans (V. natans), including seed endosphere, as well as environmental (water and bulk sediment), epiphytic (phyllosphere and rhizosphere), and endophytic (leaf and root endosphere) microhabitats of both leaves and roots representatives of the above- and below- ground niches (AGNs and BGNs), respectively. We found the bacterial communities colonized in epiphytic niches not only exhibited the highest diversity compared to adjacent environmental and endophytic niches, but also dominated the interactions between those bacterial members of neighboring niches in both AGNs and BGNs. The host plants promoted niche specificity at bacterial community-level, as confirmed by the proportion of bacterial specialists increased with plant proximity, especially in the BGNs. Furthermore, the bacterial taxa colonized in the AGNs exhibited higher horizontal and vertical transmission capacities than those in the BGNs, especially in the vertical transmission from seeds to leaves (41.38 %) than roots (0.42 %). Meanwhile, the bacterial co-occurrence network in AGNs was shown to have stronger small-world characteristics but weaker stability than those in the BGNs. Overall, this study cast new light on the plant microbiome in the aquatic environment, thus better promoting the potential development of strategies for breeding aquatic macrophyte holobiont with enhanced water purification and pollutant removal capabilities in the future.
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Affiliation(s)
- Rujia He
- State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Joint International Research Laboratory of Global Change and Water Cycle, Hohai University, Nanjing 210098, China; State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China
| | - Siwen Hu
- State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Joint International Research Laboratory of Global Change and Water Cycle, Hohai University, Nanjing 210098, China; State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China
| | - Qisheng Li
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China
| | - Dayong Zhao
- State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Joint International Research Laboratory of Global Change and Water Cycle, Hohai University, Nanjing 210098, China
| | - Qinglong L Wu
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China; Center for Evolution and Conservation Biology, Southern Marine Sciences and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511458, China; Sino-Danish Centre for Education and Research, University of Chinese Academy of Sciences, Beijing 100039, China
| | - Jin Zeng
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China; Sino-Danish Centre for Education and Research, University of Chinese Academy of Sciences, Beijing 100039, China.
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3
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Zhao X, Meng X, Dang B, Zhang T, Shi W, Hou N, Yan Q, Li C. Succession dynamics of microbial communities responding to the exogenous microalgae ZM-5 and analysis of the environmental sustainability of a constructed wetland system. BIORESOURCE TECHNOLOGY 2023; 371:128642. [PMID: 36681352 DOI: 10.1016/j.biortech.2023.128642] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 01/11/2023] [Accepted: 01/15/2023] [Indexed: 06/17/2023]
Abstract
Constructed wetlands (CWs) are economical and effective swine tailwater treatment systems. However, nitrogen removal in CWs is limited by the lack of carbon source for denitrification. In this study, we studied the feasibility of dosing the microalgae ZM-5 to improve the nitrogen removal ability in CWs. Compared to the control CW, a 20 % higher removal capacity of COD and TN was observed for the coupled system (EG). The microalgae ZM-5 could interact with denitrifying bacteria to compensate for the deficiency of denitrifying stage in CWs. HT-qPCR chip analysis also provided evidence that denitrification genes significantly increased (p < 0.05). According to the life cycle assessment (LCA), ultrasonic extraction had the best environmental sustainability among four lipid extraction processes. As an improvement strategy, clean energy could be utilized to optimize the electricity source to reduce environmental load (45 %-60 %). These findings offer new insights into the feasibility of EG for environmentally sustainable wastewater treatment.
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Affiliation(s)
- Xinyue Zhao
- College of Resource and Environment, Northeast Agricultural University, Harbin 150030, China
| | - Xiangwei Meng
- College of Resource and Environment, Northeast Agricultural University, Harbin 150030, China
| | - Bin Dang
- College of Resource and Environment, Northeast Agricultural University, Harbin 150030, China
| | - Tuoshi Zhang
- College of Resource and Environment, Northeast Agricultural University, Harbin 150030, China
| | - Wen Shi
- College of Animal Science and Technology, Northeast Agricultural University, Harbin 150030, China
| | - Ning Hou
- College of Resource and Environment, Northeast Agricultural University, Harbin 150030, China
| | - Qingsheng Yan
- Dana Farber Cancer Institute, Harvard Medical School, Boston, Ma 02215, USA
| | - Chunyan Li
- College of Resource and Environment, Northeast Agricultural University, Harbin 150030, China.
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Wang J, Guo X, Li Y, Song G, Zhao L. Understanding the Variation of Bacteria in Response to Summertime Oxygen Depletion in Water Column of Bohai Sea. Front Microbiol 2022; 13:890973. [PMID: 35756048 PMCID: PMC9221365 DOI: 10.3389/fmicb.2022.890973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Accepted: 05/05/2022] [Indexed: 11/14/2022] Open
Abstract
Aiming to reveal the variation in bacteria community under oxygen depletion formed every summer in water column of central Bohai Sea, a time-scenario sampling from June to August in 2018 at a 20-day interval along one inshore-offshore transect was settled. Water samples were collected at the surface, middle, and bottom layer and then analyzed by high-throughput sequencing targeting both 16S rRNA and nosZ genes. Compared to the surface and middle water, oxygen depletion occurred at bottom layer in August. In top two layers, Cyanobacteria dominated the bacterial community, whereas heterotrophic bacteria became dominant in bottom water of Bohai Sea. Based on the time scenario, distinct community separation was observed before (June and July) and after (August) oxygen depletion (p = 0.003). Vertically, strict stratification of nosZ gene was stably formed along 3 sampling layers. As a response to oxygen depletion, the diversity indices of both total bacteria (16S rRNA) and nosZ gene-encoded denitrification bacteria all increased, which indicated the intense potential of nitrogen lose when oxygen depleted. Dissolved oxygen (DO) was the key impacting factor on the community composition of total bacteria in June, whereas nutrients together with DO play the important roles in August for both total and denitrifying bacteria. The biotic impact was revealed further by strong correlations which showed between Cyanobacteria and heterotrophic bacteria in June from co-occurrence network analysis, which became weak in August when DO was depleted. This study discovered the variation in bacteria community in oxygen-depleted water with further effort to understand the potential role of denitrifying bacteria under oxygen depletion in Bohai Sea for the first time, which provided insights into the microbial response to the world-wide expanding oxygen depletion and their contributions in the ocean nitrogen cycling.
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Affiliation(s)
- Jing Wang
- Tianjin Key Laboratory of Animal and Plant Resistance, Tianjin Key Laboratory of Conservation and Utilization of Animal Diversity, Tianjin Normal University, Tianjin, China
| | - Xiaoxiao Guo
- Tianjin Key Laboratory of Animal and Plant Resistance, Tianjin Key Laboratory of Conservation and Utilization of Animal Diversity, Tianjin Normal University, Tianjin, China
| | - Yanying Li
- Tianjin Key Laboratory of Animal and Plant Resistance, Tianjin Key Laboratory of Conservation and Utilization of Animal Diversity, Tianjin Normal University, Tianjin, China
| | - Guisheng Song
- School of Marine Science and Technology, Tianjin University, Tianjin, China
| | - Liang Zhao
- College of Marine and Environmental Sciences, Tianjin University of Science and Technology, Tianjin, China
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5
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Yang D, Jiang C, Xu S, Gu L, Wang D, Zuo J, Wang H, Zhang S, Wang D, Zhang H, Zhuang X. Insight into nitrogen removal performance of anaerobic ammonia oxidation in two reactors: Comparison based on the aspects of extracellular polymeric substances and microbial community. Biochem Eng J 2022. [DOI: 10.1016/j.bej.2022.108526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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6
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Hall NC, Sikaroodi M, Hogan D, Jones RC, Gillevet PM. The Presence of Denitrifiers In Bacterial Communities of Urban Stormwater Best Management Practices (BMPs). ENVIRONMENTAL MANAGEMENT 2022; 69:89-110. [PMID: 34860281 PMCID: PMC8758610 DOI: 10.1007/s00267-021-01529-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Accepted: 08/05/2021] [Indexed: 06/13/2023]
Abstract
Stormwater best management practices (BMPs) are engineered structures that attempt to mitigate the impacts of stormwater, which can include nitrogen inputs from the surrounding drainage area. The goal of this study was to assess bacterial community composition in different types of stormwater BMP soils to establish whether a particular BMP type harbors more denitrification potential. Soil sampling took place over the summer of 2015 following precipitation events. Soils were sampled from four bioretention facilities, four dry ponds, four surface sand filters, and one dry swale. 16S rRNA gene analysis of extracted DNA and RNA amplicons indicated high bacterial diversity in the soils of all BMP types sampled. An abundance of denitrifiers was also indicated in the extracted DNA using presence/absence of nirS, nirK, and nosZ denitrification genes. BMP soil bacterial communities were impacted by the surrounding soil physiochemistry. Based on the identification of a metabolically-active community of denitrifiers, this study has indicated that denitrification could potentially occur under appropriate conditions in all types of BMP sampled, including surface sand filters that are often viewed as providing low potential for denitrification. The carbon content of incoming stormwater could be providing bacterial communities with denitrification conditions. The findings of this study are especially relevant for land managers in watersheds with legacy nitrogen from former agricultural land use.
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Affiliation(s)
- Natalie C Hall
- U.S. Geological Survey, Florence Bascom Geoscience Center, Reston, VA, USA.
| | - Masoumeh Sikaroodi
- Department of Biology, George Mason University, Manassas, VA, USA
- Microbiome Analysis Center (MBAC), Manassas, VA, USA
| | - Dianna Hogan
- U.S. Geological Survey, Deputy Regional Director for Science, Southeast Region, Reston, VA, USA
| | - R Christian Jones
- Department of Environmental Science and Policy, George Mason University, Fairfax, VA, USA
- Potomac Environmental Research and Education Center (PEREC), George Mason University, Woodbridge, VA, USA
| | - Patrick M Gillevet
- Department of Biology, George Mason University, Manassas, VA, USA
- Microbiome Analysis Center (MBAC), Manassas, VA, USA
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7
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Aalto SL, Suurnäkki S, von Ahnen M, Tiirola M, Pedersen PB. Microbial communities in full-scale woodchip bioreactors treating aquaculture effluents. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2022; 301:113852. [PMID: 34592671 DOI: 10.1016/j.jenvman.2021.113852] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Revised: 09/13/2021] [Accepted: 09/24/2021] [Indexed: 06/13/2023]
Abstract
Woodchip bioreactors are being successfully applied to remove nitrate from commercial land-based recirculating aquaculture system (RAS) effluents. In order to understand and optimize the overall function of these bioreactors, knowledge on the microbial communities, especially on the microbes with potential for production or mitigation of harmful substances (e.g. hydrogen sulfide; H2S) is needed. In this study, we quantified and characterized bacterial and fungal communities, including potential H2S producers and consumers, using qPCR and high throughput sequencing of 16S rRNA gene. We took water samples from bioreactors and their inlet and outlet, and sampled biofilms growing on woodchips and on the outlet of the three full-scale woodchip bioreactors treating effluents of three individual RAS. We found that bioreactors hosted a high biomass of both bacteria and fungi. Although the composition of microbial communities of the inlet varied between the bioreactors, the conditions in the bioreactors selected for the same core microbial taxa. The H2S producing sulfate reducing bacteria (SRB) were mainly found in the nitrate-limited outlets of the bioreactors, the main groups being deltaproteobacterial Desulfobulbus and Desulfovibrio. The abundance of H2S consuming sulfate oxidizing bacteria (SOB) was 5-10 times higher than that of SRB, and SOB communities were dominated by Arcobacter and other genera from phylum Epsilonbacteraeota, which are also capable of autotrophic denitrification. Indeed, the relative abundance of potential autotrophic denitrifiers of all denitrifier sequences was even 54% in outlet water samples and 56% in the outlet biofilm samples. Altogether, our results show that the highly abundant bacterial and fungal communities in woodchip bioreactors are shaped through the conditions prevailing within the bioreactor, indicating that the bioreactors with similar design and operational settings should provide similar function even when conditions in the preceding RAS would differ. Furthermore, autotrophic denitrifiers can have a significant role in woodchip biofilters, consuming potentially produced H2S and removing nitrate, lengthening the operational age and thus further improving the overall environmental benefit of these bioreactors.
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Affiliation(s)
- Sanni L Aalto
- Technical University of Denmark, DTU Aqua, Section for Aquaculture, The North Sea Research Centre, P.O. Box 101, DK-9850, Hirtshals, Denmark; Nanoscience Center, Department of Biological and Environmental Science, University of Jyväskylä, P.O. Box 35, 40014, Jyväskylä, Finland.
| | - Suvi Suurnäkki
- Nanoscience Center, Department of Biological and Environmental Science, University of Jyväskylä, P.O. Box 35, 40014, Jyväskylä, Finland
| | - Mathis von Ahnen
- Technical University of Denmark, DTU Aqua, Section for Aquaculture, The North Sea Research Centre, P.O. Box 101, DK-9850, Hirtshals, Denmark
| | - Marja Tiirola
- Nanoscience Center, Department of Biological and Environmental Science, University of Jyväskylä, P.O. Box 35, 40014, Jyväskylä, Finland
| | - Per Bovbjerg Pedersen
- Technical University of Denmark, DTU Aqua, Section for Aquaculture, The North Sea Research Centre, P.O. Box 101, DK-9850, Hirtshals, Denmark
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8
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Zhou Y, Xu X, Song K, Yeerken S, Deng M, Li L, Riya S, Wang Q, Terada A. Nonlinear pattern and algal dual-impact in N 2O emission with increasing trophic levels in shallow lakes. WATER RESEARCH 2021; 203:117489. [PMID: 34450464 DOI: 10.1016/j.watres.2021.117489] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Revised: 07/12/2021] [Accepted: 07/26/2021] [Indexed: 06/13/2023]
Abstract
Shallow lakes are considered important contributors to emissions of nitrous oxide (N2O), a powerful greenhouse gas, in aquatic ecosystems. There is a large degree of uncertainty regarding the relationship between N2O emissions and the progress of lake eutrophication, and the mechanisms underlying N2O emissions are poorly understood. Here, N2O emission fluxes and environmental variables in different lakes along a trophic state gradient in the Yangtze River basin were studied. N2O emission fluxes were -1.0-53.0 μg m-2 h-1 and 0.4-102.9 μg m-2 h-1 in summer and winter, respectively, indicating that there was marked variation in N2O emissions among lakes of different trophic state. The non-linear exponential model explained differences in N2O emission fluxes by the degree of eutrophication (p < 0.01). TN and chl-a both predicted 86% of the N2O emission fluxes in shallow lakes. The predicted N2O emission fluxes based on the IPCC EF5r overestimated the observed fluxes, particularly those in hyper-eutrophic lakes. These findings demonstrated that nutrient-rich conditions and algal accumulation are key factors determining N2O emission fluxes in shallow lakes. Furthermore, this study also revealed that temperature and algae accumulation-decomposition determine an N2O emission flux in an intricate manner. A low temperature, i.e., winter, limits algae growth and low oxygen consumption for algae decomposition. The environment leaves a high dissolved oxygen concentration, slowing down N2O consumption as the final step of denitrification. In summer, with the oxygen consumed by excess algal decomposition, the N2O production is limited by the complete denitrification as well as the limited substrate supply of nitrate by nitrification in hypoxic or anoxic conditions. Such cascading events explained the higher N2O emission fluxes from shallow lakes in winter compared with summer. This trend was amplified in hyper-eutrophic shallow lakes after algal disappearance. Collectively, algal accumulation played a dual role in stimulating and impeding N2O emissions, especially in hyper-eutrophic lakes. This study expands our knowledge of N2O emissions from shallow lakes in which eutrophication is underway.
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Affiliation(s)
- Yiwen Zhou
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; Department of Chemical Engineering, Tokyo University of Agriculture and Technology, Tokyo 184-8588, Japan
| | - Xiaoguang Xu
- School of Environment, Nanjing Normal University, Nanjing 210023, China
| | - Kang Song
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; University of Chinese Academy of Sciences, Beijing, China.
| | - Senbati Yeerken
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; University of Chinese Academy of Sciences, Beijing, China
| | - Min Deng
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Lu Li
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Shohei Riya
- Department of Chemical Engineering, Tokyo University of Agriculture and Technology, Tokyo 184-8588, Japan
| | - Qilin Wang
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, NSW 2007, Australia
| | - Akihiko Terada
- Department of Chemical Engineering, Tokyo University of Agriculture and Technology, Tokyo 184-8588, Japan
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Nyirabuhoro P, Gao X, Ndayishimiye JC, Xiao P, Mo Y, Ganjidoust H, Yang J. Responses of abundant and rare bacterioplankton to temporal change in a subtropical urban reservoir. FEMS Microbiol Ecol 2021; 97:6184044. [PMID: 33755730 DOI: 10.1093/femsec/fiab036] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Accepted: 03/04/2021] [Indexed: 11/13/2022] Open
Abstract
Investigation of bacterial community dynamics across different time scales is important for understanding how environmental conditions drive community change over time. Bacterioplankton from the surface waters of a subtropical urban reservoir in southeast China were analyzed through high-frequency sampling over 13 months to compare patterns and ecological processes between short (0‒8 weeks), medium (9‒24 weeks) and long (25‒53 weeks) time intervals. We classified the bacterial community into different subcommunities: abundant taxa (AT); conditionally rare taxa (CRT); rare taxa (RT). CRT contributed > 65% of the alpha-diversity, and temporal change of beta-diversities was more pronounced for AT and CRT than RT. The bacterial community exhibited a directional change in the short- and medium-time intervals and a convergent dynamic during the long-time interval due to a seasonal cycle. Cyanobacteria exhibited a strong succession pattern than other phyla. CRT accounted for > 76% of the network nodes in three stations. The bacteria-environment relationship and deterministic processes were stronger for large sample size at station G (n = 116) than small sample size at stations C (n = 12) and L (n = 22). These findings suggest that a high-frequency sampling approach can provide a better understanding on the time scales at which bacterioplankton can change fast between being abundant or rare, thus providing the facts about environmental factors driving microbial community dynamics. Patterns and processes in alpha- and beta-diversities and community assembly of bacterioplankton differ among different time intervals (short-, medium- and long-time intervals) and different subcommunities (abundant, conditionally rare and rare taxa) in a subtropical urban reservoir, demonstrating the importance of temporal scale and high-frequency sampling in microbial community ecology.
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Affiliation(s)
- Pascaline Nyirabuhoro
- Aquatic EcoHealth Group, Fujian Key Laboratory of Watershed Ecology, Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, P.R. China.,University of Chinese Academy of Sciences, Beijing 100049, P.R. China
| | - Xiaofei Gao
- Aquatic EcoHealth Group, Fujian Key Laboratory of Watershed Ecology, Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, P.R. China.,University of Chinese Academy of Sciences, Beijing 100049, P.R. China
| | - Jean Claude Ndayishimiye
- Aquatic EcoHealth Group, Fujian Key Laboratory of Watershed Ecology, Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, P.R. China.,University of Chinese Academy of Sciences, Beijing 100049, P.R. China
| | - Peng Xiao
- Aquatic EcoHealth Group, Fujian Key Laboratory of Watershed Ecology, Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, P.R. China
| | - Yuanyuan Mo
- Aquatic EcoHealth Group, Fujian Key Laboratory of Watershed Ecology, Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, P.R. China.,University of Chinese Academy of Sciences, Beijing 100049, P.R. China
| | - Hossein Ganjidoust
- Faculty of Civil and Environmental Engineering, Environmental Engineering Division, Tarbiat Modares University, P.O. Box 14115-397, Tehran, Iran
| | - Jun Yang
- Aquatic EcoHealth Group, Fujian Key Laboratory of Watershed Ecology, Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, P.R. China
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10
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Wang Q, Han Y, Lan S, Hu C. Metagenomic Insight Into Patterns and Mechanism of Nitrogen Cycle During Biocrust Succession. Front Microbiol 2021; 12:633428. [PMID: 33815315 PMCID: PMC8009985 DOI: 10.3389/fmicb.2021.633428] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Accepted: 02/22/2021] [Indexed: 11/13/2022] Open
Abstract
The successional ecology of nitrogen cycling in biocrusts and the linkages to ecosystem processes remains unclear. To explore this, four successional stages of natural biocrust with five batches of repeated sampling and three developmental stages of simulated biocrust were studied using relative and absolute quantified multi-omics methods. A consistent pattern across all biocrust was found where ammonium assimilation, mineralization, dissimilatory nitrite to ammonium (DNiRA), and assimilatory nitrate to ammonium were abundant, while denitrification medium, N-fixation, and ammonia oxidation were low. Mathematic analysis showed that the nitrogen cycle in natural biocrust was driven by dissolved organic N and NO3–. pH and SO42– were the strongest variables affecting denitrification, while C:(N:P) was the strongest variable affecting N-fixation, DNiRA, nitrite oxidation, and dissimilatory nitrate to nitrite. Furthermore, N-fixation and DNiRA were closely related to elemental stoichiometry and redox balance, while assimilatory nitrite to ammonium (ANiRA) and mineralization were related to hydrological cycles. Together with the absolute quantification and network models, our results suggest that responsive ANiRA and mineralization decreased during biocrust succession; whereas central respiratory DNiRA, the final step of denitrification, and the complexity and interaction of the whole nitrogen cycle network increased. Therefore, our study stresses the changing environmental functions in the biocrust N-cycle, which are succession-dependent.
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Affiliation(s)
- Qiong Wang
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Yingchun Han
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Shubin Lan
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Chunxiang Hu
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
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11
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Hakim S, Naqqash T, Nawaz MS, Laraib I, Siddique MJ, Zia R, Mirza MS, Imran A. Rhizosphere Engineering With Plant Growth-Promoting Microorganisms for Agriculture and Ecological Sustainability. FRONTIERS IN SUSTAINABLE FOOD SYSTEMS 2021. [DOI: 10.3389/fsufs.2021.617157] [Citation(s) in RCA: 62] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The rhizosphere is undoubtedly the most complex microhabitat, comprised of an integrated network of plant roots, soil, and a diverse consortium of bacteria, fungi, eukaryotes, and archaea. The rhizosphere conditions have a direct impact on crop growth and yield. Nutrient-rich rhizosphere environments stimulate plant growth and yield and vice versa. Extensive cultivation exhaust most of the soils which need to be nurtured before or during the next crop. Chemical fertilizers are the major source of crop nutrients but their uncontrolled and widespread usage has posed a serious threat to the sustainability of agriculture and stability of an ecosystem. These chemicals are accumulated in the soil, drained in water, and emitted to the air where they persist for decades causing a serious threat to the overall ecosystem. Plant growth-promoting rhizobacteria (PGPR) present in the rhizosphere convert many plant-unavailable essential nutrients e.g., nitrogen, phosphorous, zinc, etc. into available forms. PGPR produces certain plant growth hormones (such as auxin, cytokinin, and gibberellin), cell lytic enzymes (chitinase, protease, hydrolases, etc.), secondary metabolites, and antibiotics, and stress alleviating compounds (e.g., 1-Aminocyclopropane-1- carboxylate deaminase), chelating agents (siderophores), and some signaling compounds (e.g., N-Acyl homoserine lactones) to interact with the beneficial or pathogenic counterparts in the rhizosphere. These multifarious activities of PGPR improve the soil structure, health, fertility, and functioning which directly or indirectly support plant growth under normal and stressed environments. Rhizosphere engineering with these PGPR has a wide-ranging application not only for crop fertilization but developing eco-friendly sustainable agriculture. Due to severe climate change effects on plants and rhizosphere biology, there is growing interest in stress-resilient PGPM and their subsequent application to induce stress (drought, salinity, and heat) tolerance mechanism in plants. This review describes the three components of rhizosphere engineering with an explicit focus on the broader perspective of PGPM that could facilitate rhizosphere engineering in selected hosts to serve as an efficient component for sustainable agriculture.
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12
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Wang J, Cui W, Che Z, Liang F, Wen Y, Zhan M, Dong X, Jin W, Dong Z, Song H. Effects of synthetic nitrogen fertilizer and manure on fungal and bacterial contributions to N 2O production along a soil acidity gradient. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 753:142011. [PMID: 32890881 DOI: 10.1016/j.scitotenv.2020.142011] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 08/23/2020] [Accepted: 08/25/2020] [Indexed: 06/11/2023]
Abstract
Reactive nitrogen (Nr) input often induces soil acidification, which may in turn affect bacterial and fungal nitrogen (N) transformations in soil and nitrous oxide (N2O) emissions. However, the interactive effects of soil acidity and Nr on the contributions of bacteria and fungi to N2O emissions remain unclear. We conducted a field experiment to assess the effects of anthropogenic Nr forms (i.e., synthetic N fertilizer and manure) on bacterial and fungal N2O emissions along a soil acidity gradient (soil pH = 6.8, 6.1, 5.2, and 4.2). The abundances and structure of bacterial and fungal communities were analyzed by real-time polymerase chain reaction and high-throughput sequencing techniques, respectively. Soil acidification reduced bacterial but increased fungal contributions to N2O production, corresponding respectively to changes in bacterial and fungal abundance. It also altered bacterial and fungal community structures and soil chemical properties, such as dissolved organic carbon and ammonia concentrations. Structural equation modeling (SEM) analyses showed that the soil properties and fungal community were the most important factors determining bacterial and fungal contributions to N2O emissions, respectively. The fertilizer form markedly affected N2O emissions from bacteria but not from fungi. Compared with synthetic N fertilizer, manure significantly lowered the bacterial contribution to N2O emissions in the soils with pH of 5.2 and 4.2. The manure application significantly increased soil pH but reduced nitrate concentration. The fertilizer form did not significantly alter the bacterial and fungal community structures. The SEM revealed that the fertilizer form affected the bacterial contribution to N2O production by changing the soil chemical properties. Together, these results indicated that soil acidification enhanced fungal dominance for N2O emission, and manure application has limited effects on fungal N2O emission, highlighting the challenges for mitigation of soil N2O emissions under future acid deposition and N enrichment scenarios.
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Affiliation(s)
- Jun Wang
- College of Agronomy, Anhui Agricultural University, Hefei 230036, China
| | - Wenli Cui
- College of Agronomy, Anhui Agricultural University, Hefei 230036, China
| | - Zhao Che
- College of Agronomy, Anhui Agricultural University, Hefei 230036, China
| | - Fei Liang
- College of Agronomy, Anhui Agricultural University, Hefei 230036, China
| | - Yongkang Wen
- College of Agronomy, Anhui Agricultural University, Hefei 230036, China
| | - Meimei Zhan
- College of Agronomy, Anhui Agricultural University, Hefei 230036, China
| | - Xiao Dong
- School of Engineering, Anhui Agricultural University, Hefei 230036, China
| | - Wenjun Jin
- College of Agronomy, Anhui Agricultural University, Hefei 230036, China
| | - Zhaorong Dong
- College of Agronomy, Anhui Agricultural University, Hefei 230036, China
| | - He Song
- College of Agronomy, Anhui Agricultural University, Hefei 230036, China.
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13
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Huang R, Zeng J, Zhao D, Yong B, Yu Z. Co-association of Two nir Denitrifiers Under the Influence of Emergent Macrophytes. MICROBIAL ECOLOGY 2020; 80:809-821. [PMID: 32577778 DOI: 10.1007/s00248-020-01545-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Accepted: 06/15/2020] [Indexed: 06/11/2023]
Abstract
Diverse microorganisms perform similar metabolic process in biogeochemical cycles, whereas they are found of highly genomic differentiation. Biotic interactions should be considered in any community survey of these functional groups, as they contribute to community assembly and ultimately alter ecosystem properties. Current knowledge has mainly been achieved based on functional community characterized by a single gene using co-occurrence network analysis. Biotic interactions between functionally equivalent microorganisms, however, have received much less attention. Herein, we propose the nirK- and nirS-type denitrifier communities represented by these two nitrite reductase (nir)-encoding genes, as model communities to investigate the potential interactions of two nir denitrifiers. We evaluated co-occurrence patterns and co-association network structures of nir denitrifier community from an emergent macrophyte-dominated riparian zone of highly active denitrification in Lake Taihu, China. We found a more segregated pattern in combined nir communities than in individual communities. Network analyses revealed a modularized structure of associating nir denitrifiers. An increased proportion of negative associations among combined communities relative to those of individual communities indicated potential interspecific competition between nirK and nirS denitrifiers. pH and NH4+-N were the most important factors driving co-occurrence and mutual exclusion between nirK and nirS denitrifiers. We also showed the topological importance of nirK denitrifiers acting as module hubs for constructing entire association networks. We revealed previously unexplored co-association relationships between nirK and nirS denitrifiers, which were previously neglected in network analyses of individual communities. Using nir denitrifier community as a model, these findings would be helpful for us to understand the biotic interactions and mechanisms underlying how functional groups co-exist in performing biogeochemical cycles.
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Affiliation(s)
- Rui Huang
- State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, School of Earth Sciences and Engineering, Hohai University, Nanjing, 210098, China
| | - Jin Zeng
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, China.
| | - Dayong Zhao
- State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, School of Earth Sciences and Engineering, Hohai University, Nanjing, 210098, China
| | - Bin Yong
- State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, School of Earth Sciences and Engineering, Hohai University, Nanjing, 210098, China
| | - Zhongbo Yu
- State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, School of Earth Sciences and Engineering, Hohai University, Nanjing, 210098, China
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14
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Podlesnaya GV, Potapov SA, Krasnopeev AY, Shtykova YR, Tomberg IV, Timoshkin OA, Belykh OI. Diversity of Denitrifying Bacteria in Biofilms Formed on Stony Substrates of the Lake Baikal Littoral Zone. Microbiology (Reading) 2020. [DOI: 10.1134/s0026261720030133] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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15
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Garcia-Lemos AM, Gobbi A, Nicolaisen MH, Hansen LH, Roitsch T, Veierskov B, Nybroe O. Under the Christmas Tree: Belowground Bacterial Associations With Abies nordmanniana Across Production Systems and Plant Development. Front Microbiol 2020; 11:198. [PMID: 32194515 PMCID: PMC7064441 DOI: 10.3389/fmicb.2020.00198] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Accepted: 01/28/2020] [Indexed: 01/01/2023] Open
Abstract
Abies nordmanniana is an economically important tree crop widely used for Christmas tree production. After initial growth in nurseries, seedlings are transplanted to the field. Rhizosphere bacterial communities generally impact the growth and health of the host plant. However, the dynamics of these communities during A. nordmanniana growth in nurseries, and during transplanting, has not previously been addressed. By a 16S rRNA gene amplicon sequencing approach, we characterized the composition and dynamics of bacterial communities in the rhizosphere during early plant growth in field and greenhouse nurseries and for plants transplanted from the greenhouse to the field. Moreover, the N-cycling potential of rhizosphere bacteria across plant age was addressed in both nurseries. Overall, a rhizosphere core microbiome of A. nordmanniana, comprising 19.9% of the taxa at genus level, was maintained across plant age, nursery production systems, and even during the transplantation of plants from the greenhouse to the field. The core microbiome included the bacterial genera Bradyrhizobium, Burkholderia, Flavobacterium, Pseudomonas, Rhizobium, Rhodanobacter, and Sphingomonas, which harbor several N-fixing and plant growth–promoting taxa. Nevertheless, both plant age and production system caused significant changes in the rhizosphere bacterial communities. Concerning community composition, the relative abundance of Rhizobiales (genera Rhizobium, Bradyrhizobium, and Devosia) was higher in the rhizosphere of field-grown A. nordmanniana, whereas the relative abundance of Enterobacteriales and Pseudomonadales (genus Pseudomonas) was higher in the greenhouse. Analysis of community dynamics across plant age showed that in the field nursery, the most abundant bacterial orders showed more dynamic changes in their relative abundance in the rhizosphere than in the bulk soil. In the greenhouse, age-dependent dynamics even occurred but affected different taxa than for the field-grown plants. The N-cycling potential of rhizosphere bacterial communities showed an increase of the relative abundance of genes involved in nitrogen fixation and denitrification by plant age. Similarly, the relative abundance of reported nitrogen-fixing or denitrifying bacteria increased by plant age. However, different community structures seemed to lead to an increased potential for nitrogen fixation and denitrification in the field versus greenhouse nurseries.
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Affiliation(s)
- Adriana M Garcia-Lemos
- Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, Frederiksberg, Denmark
| | - Alex Gobbi
- Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, Frederiksberg, Denmark
| | - Mette Haubjerg Nicolaisen
- Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, Frederiksberg, Denmark
| | - Lars H Hansen
- Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, Frederiksberg, Denmark
| | - Thomas Roitsch
- Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, Frederiksberg, Denmark.,Department of Adaptive Biotechnologies, Global Change Research Institute, CAS, Brno, Czechia
| | - Bjarke Veierskov
- Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, Frederiksberg, Denmark
| | - Ole Nybroe
- Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, Frederiksberg, Denmark
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16
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Avşar C, Aras ES. Quantification of denitrifier genes population size and its relationship with environmental factors. Arch Microbiol 2020; 202:1181-1192. [PMID: 32076734 DOI: 10.1007/s00203-020-01826-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Revised: 01/28/2020] [Accepted: 01/30/2020] [Indexed: 10/25/2022]
Abstract
The objectives of this study were to use real-time PCR for culture-independent quantification of the copy numbers of 16S rRNA and denitrification functional genes, and also the relationships between gene copy numbers and soil physicochemical properties. In this study, qPCR analysis of the soil samples showed 16S rRNA, nirS, nirK, nosZI and nosZII average densities of 3.0 × 108, 2.25 × 107, 2.9 × 105, 4.0 × 106 and 1.75 × 107 copies per gram of dry soil, respectively. In addition, the abundances of (nirS + nirK), nosZI and nosZII relative to 16S rRNA genes were 1.4-34.1%, 0.06-3.95% and 1.3-39%, respectively, confirming the low proportion of denitrifiers to total bacteria in soil. This showed that the non-denitrifying nosZII-type bacteria may contribute significantly to N2O consumption in the soil. Furthermore, the shifts in abundance and diversity of the total bacteria and denitrification functional gene copy numbers correlated significantly with the various soil factors. It is the first study in Turkey about the population size of denitrification functional genes in different soil samples. It also aims to draw attention to nitrous oxide-associated global warming.
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Affiliation(s)
- Cumhur Avşar
- Department of Biology, Faculty of Arts and Sciences, Sinop University, Sinop, Turkey.
| | - E Sümer Aras
- Department of Biology, Faculty of Science, Ankara University, Ankara, Turkey
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17
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Denitrification characterization of dissolved oxygen microprofiles in lake surface sediment through analyzing abundance, expression, community composition and enzymatic activities of denitrifier functional genes. AMB Express 2019; 9:129. [PMID: 31428884 PMCID: PMC6702497 DOI: 10.1186/s13568-019-0855-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Accepted: 08/08/2019] [Indexed: 12/12/2022] Open
Abstract
The responses of denitrifiers and denitrification ability to dissolved oxygen (DO) concent in different layers of surface lake sediments are still poorly understood. Here, the optimal denitrification condition was constructed based on response surface methodology (RSM) to analyze the denitrification characteristics of surface sediments. The aerobic zone (AEZ), hypoxic zone (HYZ), up-anoxic zone (ANZ-1) and sub-anoxic zone (ANZ-2) were partitioned based on the oxygen contents, and sediments were collected using a customized-designed sub-millimeter scale sampling device. Integrated real-time quantitative PCR, Illumina Miseq-based sequencing and denitrifying enzyme activities analysis revealed that denitrification characteristics varied among different DO layers. Among the four layers, the DNA abundance and RNA expression levels of norB, nirS and nosZ were the highest at the aerobic layer, hypoxic layer and up-axoic layer, respectively. The hypoxia and up-anaerobic layer were the active nitrogen removal layers, since these two layers displayed the highest DNA abundance, RNA expression level and enzyme activities of denitrification functional genes. The abundance of major denitrifying bacteria showed significant differences among layers, with Azoarcus, Pseudogulbenkiania and Rhizobium identified as the main nirS, nirK and nosZ-based denitrifiers. Pearson’s correlation revealed that the response of denitrifiers to environmental factors differed greatly among DO layers. Furthermore, napA showed higher DNA abundance and RNA expression level in the aerobic and hypoxic layers than anaerobic layers, indicating that aerobic denitrifiers might play important roles at these layers.
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18
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Deng Z, Wang Z, Zhang P, Xia P, Ma K, Zhang D, Wang L, Yang Y, Wang Y, Chen S, Deng S. Effects of divalent copper on microbial community, enzymatic activity and functional genes associated with nitrification and denitrification at tetracycline stress. Enzyme Microb Technol 2019; 126:62-68. [DOI: 10.1016/j.enzmictec.2019.03.007] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Revised: 03/17/2019] [Accepted: 03/23/2019] [Indexed: 02/06/2023]
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19
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Palacin-Lizarbe C, Camarero L, Hallin S, Jones CM, Cáliz J, Casamayor EO, Catalan J. The DNRA-Denitrification Dichotomy Differentiates Nitrogen Transformation Pathways in Mountain Lake Benthic Habitats. Front Microbiol 2019; 10:1229. [PMID: 31214153 PMCID: PMC6558203 DOI: 10.3389/fmicb.2019.01229] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Accepted: 05/16/2019] [Indexed: 01/04/2023] Open
Abstract
Effects of nitrogen (N) deposition on microbially-driven processes in oligotrophic freshwater ecosystems are poorly understood. We quantified guilds in the main N-transformation pathways in benthic habitats of 11 mountain lakes along a dissolved inorganic nitrogen gradient. The genes involved in denitrification (nirS, nirK, nosZ), nitrification (archaeal and bacterial amoA), dissimilatory nitrate reduction to ammonium (DNRA, nrfA) and anaerobic ammonium oxidation (anammox, hdh) were quantified, and the bacterial 16S rRNA gene was sequenced. The dominant pathways and associated bacterial communities defined four main N-transforming clusters that differed across habitat types. DNRA dominated in the sediments, except in the upper layers of more productive lakes where nirS denitrifiers prevailed with potential N2O release. Loss as N2 was more likely in lithic biofilms, as indicated by the higher hdh and nosZ abundances. Archaeal ammonia oxidisers predominated in the isoetid rhizosphere and rocky littoral sediments, suggesting nitrifying hotspots. Overall, we observed a change in potential for reactive N recycling via DNRA to N losses via denitrification as lake productivity increases in oligotrophic mountain lakes. Thus, N deposition results in a shift in genetic potential from an internal N accumulation to an atmospheric release in the respective lake systems, with increased risk for N2O emissions from productive lakes.
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Affiliation(s)
- Carlos Palacin-Lizarbe
- Centro de Investigación Ecológica y Aplicaciones Forestales, Cerdanyola del Vallès, Spain
| | - Lluís Camarero
- Center for Advanced Studies of Blanes, (CEAB-CSIC), Girona, Spain
| | - Sara Hallin
- Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Christopher M Jones
- Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Joan Cáliz
- Center for Advanced Studies of Blanes, (CEAB-CSIC), Girona, Spain
| | | | - Jordi Catalan
- Centro de Investigación Ecológica y Aplicaciones Forestales, Cerdanyola del Vallès, Spain.,Consejo Superior de Investigaciones Científicas, Cerdanyola del Vallès, Spain
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20
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Achouak W, Abrouk D, Guyonnet J, Barakat M, Ortet P, Simon L, Lerondelle C, Heulin T, Haichar FEZ. Plant hosts control microbial denitrification activity. FEMS Microbiol Ecol 2019; 95:5307930. [DOI: 10.1093/femsec/fiz021] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2018] [Accepted: 02/05/2019] [Indexed: 11/13/2022] Open
Affiliation(s)
- Wafa Achouak
- Aix Marseille Univ, CEA, CNRS, Laboratory for Microbial Ecology and Extreme Environment (LEMiRE), UMR7265 BVME, F-13108 Saint-Paul-lez-Durance, France
- Aix Marseille Univ, CNRS, FR 3098 ECCOREV, F-13545 Aix-en-Provence, France
| | - Danis Abrouk
- Université de Lyon, Université Lyon1, CNRS, UMR5557, INRA 1418, Ecologie Microbienne, Villeurbanne F-69622, France
| | - Julien Guyonnet
- Université de Lyon, Université Lyon1, CNRS, UMR5557, INRA 1418, Ecologie Microbienne, Villeurbanne F-69622, France
| | - Mohamed Barakat
- Aix Marseille Univ, CEA, CNRS, Laboratory for Microbial Ecology and Extreme Environment (LEMiRE), UMR7265 BVME, F-13108 Saint-Paul-lez-Durance, France
- Aix Marseille Univ, CNRS, FR 3098 ECCOREV, F-13545 Aix-en-Provence, France
| | - Philippe Ortet
- Aix Marseille Univ, CEA, CNRS, Laboratory for Microbial Ecology and Extreme Environment (LEMiRE), UMR7265 BVME, F-13108 Saint-Paul-lez-Durance, France
- Aix Marseille Univ, CNRS, FR 3098 ECCOREV, F-13545 Aix-en-Provence, France
| | - Laurent Simon
- Université de Lyon, Université Lyon 1, UMR5023 LEHNA, CNRS, ENTPE, F‐69622 Villeurbanne Cedex, France
| | - Catherine Lerondelle
- Université de Lyon, Université Lyon1, CNRS, UMR5557, INRA 1418, Ecologie Microbienne, Villeurbanne F-69622, France
| | - Thierry Heulin
- Aix Marseille Univ, CEA, CNRS, Laboratory for Microbial Ecology and Extreme Environment (LEMiRE), UMR7265 BVME, F-13108 Saint-Paul-lez-Durance, France
- Aix Marseille Univ, CNRS, FR 3098 ECCOREV, F-13545 Aix-en-Provence, France
| | - Feth el Zahar Haichar
- Université de Lyon, Université Lyon1, CNRS, UMR5557, INRA 1418, Ecologie Microbienne, Villeurbanne F-69622, France
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21
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Igielski S, Kjellerup BV, Davis AP. Understanding urban stormwater denitrification in bioretention internal water storage zones. WATER ENVIRONMENT RESEARCH : A RESEARCH PUBLICATION OF THE WATER ENVIRONMENT FEDERATION 2019; 91:32-44. [PMID: 30682230 DOI: 10.2175/106143017x15131012188024] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Accepted: 07/10/2018] [Indexed: 06/09/2023]
Abstract
Conventional free-draining bioretention systems promote nitrate production and continual leaching to receiving waters. In this study, laboratory tests demonstrated the efficacy of an internal water storage zone (IWSZ) to target nitrate removal via denitrification. Experimental results confirmed that the carbon substrate characteristics (Willow Oak woodchip media) and the hydraulic retention time of nitrified stormwater affected nitrate removal performance. A 2.6-day batch treatment time reduced 3.0 mg-N/L to <0.01 mg/L, corresponding to a first-order denitrification rate constant of 0.0011 min-1 . Under various flow conditions, the associated hydraulic retention time may be used as a predictive measurement of nitrate removal performance. Scanning electron microscopy and 16S rRNA analysis of the woodchips showed that biofilms were present that could be responsible for anaerobic lignocellulose degradation and denitrification. This knowledge, along with evaluation of the biofilm community composition, reinforced the notion of a heterogeneous structure due to nutrient availability and hydrodynamic conditions. PRACTITIONER POINTS: Denitrification can occur using woodchips in a bioretention internal water storage zone. The denitrification rate is slow and may be limited during field-scale applications. A woodchip pretreatment did not provide long-term enhancement to the denitrification rate. Denitrification bacteria were found in the internal water storage zone.
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Affiliation(s)
- Sara Igielski
- Department of Civil and Environmental Engineering, University of Maryland, College Park, MD, USA
| | - Birthe V Kjellerup
- Department of Civil and Environmental Engineering, University of Maryland, College Park, MD, USA
| | - Allen P Davis
- Department of Civil and Environmental Engineering, University of Maryland, College Park, MD, USA
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22
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Suleiman AKA, Lourenço KS, Pitombo LM, Mendes LW, Roesch LFW, Pijl A, Carmo JB, Cantarella H, Kuramae EE. Recycling organic residues in agriculture impacts soil-borne microbial community structure, function and N 2O emissions. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 631-632:1089-1099. [PMID: 29727935 DOI: 10.1016/j.scitotenv.2018.03.116] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Revised: 03/10/2018] [Accepted: 03/10/2018] [Indexed: 06/08/2023]
Abstract
Recycling residues is a sustainable alternative to improve soil structure and increase the stock of nutrients. However, information about the magnitude and duration of disturbances caused by crop and industrial wastes on soil microbial community structure and function is still scarce. The objective of this study was to investigate how added residues from industry and crops together with nitrogen (N) fertiliser affect the microbial community structure and function, and nitrous oxide (N2O) emissions. The experimental sugarcane field had the following treatments: (I) control with nitrogen, phosphorus, and potassium (NPK), (II) sugarcane straw with NPK, (III) vinasse (by-product of ethanol industry) with NP, and (IV) vinasse plus sugarcane straw with NP. Soil samples were collected on days 1, 3, 6, 11, 24 and 46 of the experiment for DNA extraction and metagenome sequencing. N2O emissions were also measured. Treatments with straw and vinasse residues induced changes in soil microbial composition and potential functions. The change in the microbial community was highest in the treatments with straw addition with functions related to decomposition of different ranges of C-compounds overrepresented while in vinasse treatment, the functions related to spore-producing microorganisms were overrepresented. Furthermore, all additional residues increased microorganisms related to the nitrogen metabolism and vinasse with straw had a synergetic effect on the highest N2O emissions. The results highlight the importance of residues and fertiliser management in sustainable agriculture.
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Affiliation(s)
- Afnan Khalil Ahmad Suleiman
- Microbial Ecology Department, Netherlands Institute of Ecology (NIOO), Droevendaalsesteeg 10, 6708 PB Wageningen, The Netherlands
| | - Késia Silva Lourenço
- Microbial Ecology Department, Netherlands Institute of Ecology (NIOO), Droevendaalsesteeg 10, 6708 PB Wageningen, The Netherlands; Soils and Environmental Resources Center, Agronomic Institute of Campinas (IAC), Av. Barão de Itapura 1481, 13020-902 Campinas, SP, Brazil; Institute of Biology Leiden, Leiden University, Netherlands
| | - Leonardo Machado Pitombo
- Department of Environmental Sciences, Federal University of São Carlos (UFSCar), Rod. João Leme dos Santos Km 110, 18052-780 Sorocaba, SP, Brazil
| | - Lucas William Mendes
- Microbial Ecology Department, Netherlands Institute of Ecology (NIOO), Droevendaalsesteeg 10, 6708 PB Wageningen, The Netherlands
| | - Luiz Fernando Wurdig Roesch
- Centro Interdisciplinar de Pesquisas em Biotecnologia, Universidade Federal do Pampa (UNIPAMPA), Avenida Antônio Trilha 1847, 97300-000 São Gabriel, Brazil
| | - Agata Pijl
- Microbial Ecology Department, Netherlands Institute of Ecology (NIOO), Droevendaalsesteeg 10, 6708 PB Wageningen, The Netherlands
| | - Janaína Braga Carmo
- Department of Environmental Sciences, Federal University of São Carlos (UFSCar), Rod. João Leme dos Santos Km 110, 18052-780 Sorocaba, SP, Brazil
| | - Heitor Cantarella
- Soils and Environmental Resources Center, Agronomic Institute of Campinas (IAC), Av. Barão de Itapura 1481, 13020-902 Campinas, SP, Brazil
| | - Eiko Eurya Kuramae
- Microbial Ecology Department, Netherlands Institute of Ecology (NIOO), Droevendaalsesteeg 10, 6708 PB Wageningen, The Netherlands.
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23
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Xing W, Li J, Li D, Hu J, Deng S, Cui Y, Yao H. Stable-Isotope Probing Reveals the Activity and Function of Autotrophic and Heterotrophic Denitrifiers in Nitrate Removal from Organic-Limited Wastewater. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:7867-7875. [PMID: 29902378 DOI: 10.1021/acs.est.8b01993] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Combined heterotrophic and autotrophic denitrification (HAD) is a sustainable and practical method for removing nitrate from organic-limited wastewater. However, the active microorganisms responsible for denitrification in wastewater treatment have not been clearly identified. In this study, a combined microelectrolysis, heterotrophic, and autotrophic denitrification (CEHAD) process was established. DNA-based stable isotope probing was employed to identify the active denitrifiers in reactors fed with either 13C-labeled inorganic or organic carbon sources. The total nitrogen removal efficiencies reached 87.2-92.8% at a low organic carbon concentration (20 mg/L COD). Real-time polymerase chain reaction of the nirS gene as a function of the DNA buoyant density following the ultracentrifugation of the total DNA indicated marked 13C-labeling of active denitrifiers. High-throughput sequencing of the fractionated DNA in H13CO3-/12CH312COO--fed and H12CO3-/13CH313COO--fed reactors revealed that Thermomonas-like phylotypes were labeled by 13C-bicarbonate, while Thauera-like and Comamonas-like phylotypes were labeled by 13C-acetate. Meanwhile, Arenimonas-like and Rubellimicrobium-like phylotypes were recovered in the "heavy" DNA fractions from both reactors. These results suggest that nitrate removal in CEHAD is catalyzed by various active microorganisms, including autotrophs, heterotrophs, and mixotrophs. Our findings provide a better understanding of the mechanism of nitrogen removal from organic-limited water and wastewater and can be applied to further optimize such processes.
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Affiliation(s)
- Wei Xing
- School of Civil Engineering , Beijing Jiaotong University , Beijing 100044 , China
- Beijing Key Laboratory of Aqueous Typical Pollutants Control and Water Quality Safeguard , Beijing 100044 , China
| | - Jinlong Li
- School of Civil Engineering , Beijing Jiaotong University , Beijing 100044 , China
| | - Desheng Li
- School of Civil Engineering , Beijing Jiaotong University , Beijing 100044 , China
- Beijing Key Laboratory of Aqueous Typical Pollutants Control and Water Quality Safeguard , Beijing 100044 , China
| | - Jincui Hu
- School of Civil Engineering , Beijing Jiaotong University , Beijing 100044 , China
| | - Shihai Deng
- School of Civil Engineering , Beijing Jiaotong University , Beijing 100044 , China
| | - Yuwei Cui
- School of Civil Engineering , Beijing Jiaotong University , Beijing 100044 , China
| | - Hong Yao
- School of Civil Engineering , Beijing Jiaotong University , Beijing 100044 , China
- Beijing Key Laboratory of Aqueous Typical Pollutants Control and Water Quality Safeguard , Beijing 100044 , China
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24
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Liu J, Li C, Jing J, Zhao P, Luo Z, Cao M, Ma Z, Jia T, Chai B. Ecological patterns and adaptability of bacterial communities in alkaline copper mine drainage. WATER RESEARCH 2018; 133:99-109. [PMID: 29367051 DOI: 10.1016/j.watres.2018.01.014] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Revised: 12/31/2017] [Accepted: 01/05/2018] [Indexed: 06/07/2023]
Abstract
Environmental gradient have strong effects on community assembly processes. In order to reveal the effects of alkaline mine drainage (AlkMD) on bacterial and denitrifying bacterial community compositions and diversity in tailings reservoir, here we conducted an experiment to examine all and core bacterial taxa and denitrifying functional genes's (nirS, nirK, nosZΙ) abundance along a chemical gradient in tailings water in Shibahe copper tailings in Zhongtiaoshan, China. Differences in bacterial and denitrifying bacterial community compositions in different habitats and their relationships with environmental parameters were analyzed. The results showed that the richness and diversity of bacterial community in downstream seeping water (SDSW) were the largest, while that in upstream tailings water (STW1) were the lowest. The diversity and abundance of bacterial communities tended to increase from STW1 to SDSW. The variation of bacterial community diversity was significantly related to electroconductibility (EC), nitrate (NO3-), nitrite (NO2-), total carbon (TC), inorganic carbon (IC) and sulfate (SO42-), but was not correlated with geographic distance in local scale. Core taxa from class to genus were all significantly related to NO3- and NO2-. Core taxa Rhodobacteraceae, Rhodobacter, Acinetobacter and Hydrogenophaga were typical denitrifying bacteria. The variation trends of these groups were consistent with the copy number of nirS, nirK and nosZΙ, demonstrating their importance in the process of nitrogen reduction. The copy number of nirK, nosZΙ and nirS/16S rDNA, nirK/16Sr DNA correlated strongly with NO3-, NO2- and IC, but nirS and nosZI/16SrDNA had no significant correlation with NO3- and NO2-. The copy numbers of denitrifying functional genes (nirS, nirK and nosZΙ) were negatively correlated with heavy metal plumbum (Pb) and zinc (Zn). It showed that heavy metal contamination was an important factor affecting the structure of denitrifying bacterial community in AlkMD. In this study we have identified the distribution pattern of bacterial community along physiochemical gradients in alkaline tailings reservoir and displayed the driving force of shaping the structure of bacterial community. The influence of NO3-, NO2-, IC and heavy metal Pb and Zn on bacterial community might via their influence on the functional groups involving nitrogen, carbon and metal metabolisms.
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Affiliation(s)
- Jinxian Liu
- Institute of Loess Plateau, Shanxi University, Taiyuan, 030006, China
| | - Cui Li
- Faculty of Environment Economics, Shanxi University of Finance and Economics, Taiyuan, 030006, China
| | - Juhui Jing
- Institute of Biotechnology, Shanxi University, Taiyuan, 030006, China
| | - Pengyu Zhao
- Institute of Loess Plateau, Shanxi University, Taiyuan, 030006, China
| | - Zhengming Luo
- Institute of Loess Plateau, Shanxi University, Taiyuan, 030006, China
| | - Miaowen Cao
- Institute of Loess Plateau, Shanxi University, Taiyuan, 030006, China
| | - Zhuanzhuan Ma
- Institute of Biotechnology, Shanxi University, Taiyuan, 030006, China
| | - Tong Jia
- Institute of Loess Plateau, Shanxi University, Taiyuan, 030006, China
| | - Baofeng Chai
- Institute of Loess Plateau, Shanxi University, Taiyuan, 030006, China.
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25
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Zhang Y, Wang X, Zhen Y, Mi T, He H, Yu Z. Microbial Diversity and Community Structure of Sulfate-Reducing and Sulfur-Oxidizing Bacteria in Sediment Cores from the East China Sea. Front Microbiol 2017; 8:2133. [PMID: 29163420 PMCID: PMC5682103 DOI: 10.3389/fmicb.2017.02133] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2017] [Accepted: 10/18/2017] [Indexed: 02/03/2023] Open
Abstract
Sulfate-reducing bacteria (SRB) and sulfur-oxidizing bacteria (SOB) have been studied extensively in marine sediments because of their vital roles in both sulfur and carbon cycles, but the available information regarding the highly diverse SRB and SOB communities is not comprehensive. High-throughput sequencing of functional gene amplicons provides tremendous insight into the structure and functional potential of complex microbial communities. Here, we explored the community structure, diversity, and abundance of SRB and SOB simultaneously through 16S rRNA, dsrB and soxB gene high-throughput sequencing and quantitative PCR analyses of core samples from the East China Sea. Overall, high-throughput sequencing of the dsrB and soxB genes achieved almost complete coverage (>99%) and revealed the high diversity, richness, and operational taxonomic unit (OTU) numbers of the SRB and SOB communities, which suggest the existence of an active sulfur cycle in the study area. Further analysis demonstrated that rare species make vital contributions to the high richness, diversity, and OTU numbers obtained. Depth-based distributions of the dsrB, soxB, and 16S rRNA gene abundances indicated that the SRB abundance might be more sensitive to the sedimentary dynamic environment than those of total bacteria and SOB. In addition, the results of unweighted pair group method with arithmetic mean (UPGMA) clustering analysis and redundancy analysis revealed that environmental parameters, such as depth and dissolved inorganic nitrogen concentrations, and the sedimentary dynamic environment, which differed between the two sampling stations, can significantly influence the community structures of total bacteria, SRB, and SOB. This study provided further comprehensive information regarding the characteristics of SRB and SOB communities.
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Affiliation(s)
- Yu Zhang
- College of Environmental Science and Engineering, Ocean University of China, Qingdao, China.,Key Laboratory of Marine Environment and Ecology, Ministry of Education, Qingdao, China.,Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Xungong Wang
- College of Environmental Science and Engineering, Ocean University of China, Qingdao, China.,Key Laboratory of Marine Environment and Ecology, Ministry of Education, Qingdao, China.,Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Yu Zhen
- College of Environmental Science and Engineering, Ocean University of China, Qingdao, China.,Key Laboratory of Marine Environment and Ecology, Ministry of Education, Qingdao, China.,Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Tiezhu Mi
- College of Environmental Science and Engineering, Ocean University of China, Qingdao, China.,Key Laboratory of Marine Environment and Ecology, Ministry of Education, Qingdao, China.,Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Hui He
- Key Laboratory of Marine Environment and Ecology, Ministry of Education, Qingdao, China.,Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China.,College of Marine Life Science, Ocean University of China, Qingdao, China
| | - Zhigang Yu
- Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China.,Key Laboratory of Marine Chemical Theory and Technology, Ministry of Education, Qingdao, China
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26
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Castellano-Hinojosa A, Correa-Galeote D, Carrillo P, Bedmar EJ, Medina-Sánchez JM. Denitrification and Biodiversity of Denitrifiers in a High-Mountain Mediterranean Lake. Front Microbiol 2017; 8:1911. [PMID: 29056928 PMCID: PMC5635049 DOI: 10.3389/fmicb.2017.01911] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Accepted: 09/19/2017] [Indexed: 11/13/2022] Open
Abstract
Wet deposition of reactive nitrogen (Nr) species is considered a main factor contributing to N inputs, of which nitrate ([Formula: see text]) is usually the major component in high-mountain lakes. The microbial group of denitrifiers are largely responsible for reduction of nitrate to molecular dinitrogen (N2) in terrestrial and aquatic ecosystems, but the role of denitrification in removal of contaminant nitrates in high-mountain lakes is not well understood. We have used the oligotrophic, high-altitude La Caldera lake in the Sierra Nevada range (Spain) as a model to study the role of denitrification in nitrate removal. Dissolved inorganic Nr concentration in the water column of la Caldera, mainly nitrate, decreased over the ice-free season which was not associated with growth of microbial plankton or variations in the ultraviolet radiation. Denitrification activity, estimated as nitrous oxide (N2O) production, was measured in the water column and in sediments of the lake, and had maximal values in the month of August. Relative abundance of denitrifying bacteria in sediments was studied by quantitative polymerase chain reaction of the 16S rRNA and the two phylogenetically distinct clades nosZI and nosZII genes encoding nitrous oxide reductases. Diversity of denitrifiers in sediments was assessed using a culture-dependent approach and after the construction of clone libraries employing the nosZI gene as a molecular marker. In addition to genera Polymorphum, Paracoccus, Azospirillum, Pseudomonas, Hyphomicrobium, Thauera, and Methylophaga, which were present in the clone libraries, Arthrobacter, Burkholderia, and Rhizobium were also detected in culture media that were not found in the clone libraries. Analysis of biological activities involved in the C, N, P, and S cycles from sediments revealed that nitrate was not a limiting nutrient in the lake, allowed N2O production and determined denitrifiers' community structure. All these results indicate that denitrification could be a major biochemical process responsible for the N losses that occur in La Caldera lake.
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Affiliation(s)
- Antonio Castellano-Hinojosa
- Departamento de Microbiología del Suelo y Sistemas Simbióticos, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Granada, Spain.,Instituto Universitario de Investigación del Agua, Universidad de Granada, Granada, Spain
| | - David Correa-Galeote
- Departamento de Microbiología del Suelo y Sistemas Simbióticos, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Granada, Spain
| | - Presentación Carrillo
- Instituto Universitario de Investigación del Agua, Universidad de Granada, Granada, Spain.,Departamento de Ecología, Facultad de Ciencias, Universidad de Granada, Granada, Spain
| | - Eulogio J Bedmar
- Departamento de Microbiología del Suelo y Sistemas Simbióticos, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Granada, Spain
| | - Juan M Medina-Sánchez
- Instituto Universitario de Investigación del Agua, Universidad de Granada, Granada, Spain.,Departamento de Ecología, Facultad de Ciencias, Universidad de Granada, Granada, Spain
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27
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Lee JA, Francis CA. Deep nirS amplicon sequencing of San Francisco Bay sediments enables prediction of geography and environmental conditions from denitrifying community composition. Environ Microbiol 2017; 19:4897-4912. [PMID: 28892301 DOI: 10.1111/1462-2920.13920] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2017] [Accepted: 08/26/2017] [Indexed: 12/21/2022]
Abstract
Denitrification is a dominant nitrogen loss process in the sediments of San Francisco Bay. In this study, we sought to understand the ecology of denitrifying bacteria by using next-generation sequencing (NGS) to survey the diversity of a denitrification functional gene, nirS (encoding cytchrome-cd1 nitrite reductase), along the salinity gradient of San Francisco Bay over the course of a year. We compared our dataset to a library of nirS sequences obtained previously from the same samples by standard PCR cloning and Sanger sequencing, and showed that both methods similarly demonstrated geography, salinity and, to a lesser extent, nitrogen, to be strong determinants of community composition. Furthermore, the depth afforded by NGS enabled novel techniques for measuring the association between environment and community composition. We used Random Forests modelling to demonstrate that the site and salinity of a sample could be predicted from its nirS sequences, and to identify indicator taxa associated with those environmental characteristics. This work contributes significantly to our understanding of the distribution and dynamics of denitrifying communities in San Francisco Bay, and provides valuable tools for the further study of this key N-cycling guild in all estuarine systems.
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Affiliation(s)
- Jessica A Lee
- Department of Earth System Science, Stanford University, Stanford, CA, USA
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28
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Jiang X, Yao L, Guo L, Liu G, Liu W. Multi-scale factors affecting composition, diversity, and abundance of sediment denitrifying microorganisms in Yangtze lakes. Appl Microbiol Biotechnol 2017; 101:8015-8027. [PMID: 28956101 DOI: 10.1007/s00253-017-8537-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Revised: 09/11/2017] [Accepted: 09/17/2017] [Indexed: 11/25/2022]
Abstract
Sediment denitrification is the dominant nitrogen removal pathway in many aquatic habitats and can be regulated by local-, landscape-, and regional-scale factors. However, the mechanisms for how these multiple scale factors and their interactions affect the sediment denitrifying communities remain poorly understood. In this study, we investigated the community composition, diversity, and abundance of nitrite reductase genes (nirK and nirS)-encoding denitrifiers in 74 sediment samples from 22 Yangtze lakes using clone library and quantitative PCR techniques. Information of location, climate, catchment land use, water quality, sediment properties, and plant communities at each sampling site was analyzed to elucidate the effects of regional, landscape, and local factors on the characteristics of sediment denitrifying communities. Results of canonical correspondence analysis indicated that local factors were the key determinants of denitrifying community composition, accounting for over 20% of the total variation. Additionally, certain regional and landscape factors, including elevation and catchment built-up land, were also significantly related to the composition of denitrifying communities. Variance partitioning analyses revealed that diversity and abundance in the nirK denitrifier community were largely influenced by local factors, while those in the nirS community were controlled by both local and regional factors. Our findings highlight the importance of using different scale factors to explain adequately the composition and structure of denitrifying communities in aquatic environments.
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Affiliation(s)
- Xiaoliang Jiang
- Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Lumo Road No.1, Wuchang District, Wuhan, 430074, China
| | - Lu Yao
- Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Lumo Road No.1, Wuchang District, Wuhan, 430074, China
| | - Laodong Guo
- School of Freshwater Sciences, University of Wisconsin-Milwaukee, Milwaukee, 53204, USA
| | - Guihua Liu
- Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Lumo Road No.1, Wuchang District, Wuhan, 430074, China
| | - Wenzhi Liu
- Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Lumo Road No.1, Wuchang District, Wuhan, 430074, China.
- School of Freshwater Sciences, University of Wisconsin-Milwaukee, Milwaukee, 53204, USA.
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29
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Chen R, Deng M, He X, Hou J. Enhancing Nitrate Removal from Freshwater Pond by Regulating Carbon/Nitrogen Ratio. Front Microbiol 2017; 8:1712. [PMID: 28943869 PMCID: PMC5596099 DOI: 10.3389/fmicb.2017.01712] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Accepted: 08/24/2017] [Indexed: 11/13/2022] Open
Abstract
Nitrogen accumulation is a serious environmental problem in freshwater ponds, which can lead to massive death of fish and shrimps as well as the eutrophication. The removal of nitrate by regulating the carbon to nitrogen (C/N) ratio and the underlying mechanisms were investigated. The nitrate removal system comprised 530-mL medium containing 5 mg/L NO3−-N and 0–66.6 mg/L COD (i.e., C/N ratio of 0–13.3) and 20 g ponds sediments. When the C/N ratio was higher than 8, the nitrate removal efficiency nearly reached 100% during the incubation period and the accumulation of nitrite was negligible. When the C/N ratio was below 8, the nitrate removal efficiency was lower and significant nitrite accumulation occurred. The nitrate removal rate increased with the C/N ratio increased, which was ascribed to the increase in the absolute abundance of denitrifiers (nirS, nirK, and nosZ). Although both nirS-type and nirK-type denitrifiers were found in the sediments of freshwater pond, nirS-type denitrifiers were predominant. Dechloromonas was the major nirS-type denitrifier for nitrate removal in nirS-type with the C/N ratios above 5.33, while the majority of the nirK-type denitrifiers were unclassified. Thus, this study implied that the appropriate C/N ratio played an important role on the removal of excess nitrate from freshwater ponds.
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Affiliation(s)
- Rong Chen
- College of Fisheries, Huazhong Agricultural UniversityWuhan, China.,School of Environmental Studies, China University of GeosciencesWuhan, China
| | - Min Deng
- College of Fisheries, Huazhong Agricultural UniversityWuhan, China
| | - Xugang He
- College of Fisheries, Huazhong Agricultural UniversityWuhan, China.,Freshwater Aquaculture Collaborative Innovation Center of Hubei ProvinceWuhan, China.,Hubei Provincial Engineering Laboratory for Pond AquacultureWuhan, China
| | - Jie Hou
- College of Fisheries, Huazhong Agricultural UniversityWuhan, China
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30
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Herrmann M, Opitz S, Harzer R, Totsche KU, Küsel K. Attached and Suspended Denitrifier Communities in Pristine Limestone Aquifers Harbor High Fractions of Potential Autotrophs Oxidizing Reduced Iron and Sulfur Compounds. MICROBIAL ECOLOGY 2017; 74:264-277. [PMID: 28214969 DOI: 10.1007/s00248-017-0950-x] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Accepted: 02/09/2017] [Indexed: 06/06/2023]
Abstract
Oxygen and nitrate availability as well as the presence of suitable organic or inorganic electron donors are strong drivers of denitrification; however, the factors influencing denitrifier abundance and community composition in pristine aquifers are not well understood. We explored the denitrifier community structure of suspended and attached groundwater microorganisms in two superimposed limestone aquifer assemblages with contrasting oxygen regime in the Hainich Critical Zone Exploratory (Germany). Attached communities were retrieved from freshly crushed parent rock material which had been exposed for colonization in two groundwater wells (12.7 and 48 m depth). Quantitative PCR and amplicon pyrosequencing of nirK and nirS genes encoding copper-containing or cytochrome cd1 heme-type nitrite reductase, respectively, and of bacterial 16S ribosomal RNA genes showed a numerical predominance of nirS-type denitrifiers in both attached and suspended groundwater communities and a dominance of nirS-type denitrifiers closely related to the autotrophic thiosulfate- and hydrogen-oxidizing Sulfuritalea hydrogenivorans and the iron- and sulfide-oxidizing Sideroxydans lithotrophicus ES-1. Potential rates of nitrate reduction in association with exposed crushed rock material were higher with an inorganic electron donor (thiosulfate) compared to an organic electron donor (fumarate/acetate) in the upper aquifer assemblage but similar in the lower, oxic aquifer. Our results have clearly demonstrated that groundwater from pristine limestone aquifers harbors diverse denitrifier communities which appear to selectively attach to rock surfaces and harbor a high potential for nitrate reduction. Our findings suggest that the availability of suitable inorganic versus organic electron donors rather than oxygen availability shapes denitrifier communities and their potential activity in these limestone aquifers.
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Affiliation(s)
- M Herrmann
- Aquatic Geomicrobiology, Institute of Ecology, Friedrich Schiller University Jena, Dornburger Strasse 159, 07743, Jena, Germany.
- German Center for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Deutscher Platz 5e, 04103, Leipzig, Germany.
| | - S Opitz
- Aquatic Geomicrobiology, Institute of Ecology, Friedrich Schiller University Jena, Dornburger Strasse 159, 07743, Jena, Germany
| | - R Harzer
- Aquatic Geomicrobiology, Institute of Ecology, Friedrich Schiller University Jena, Dornburger Strasse 159, 07743, Jena, Germany
| | - K U Totsche
- Institute of Geosciences, Friedrich Schiller University Jena, Burgweg 11, 07749, Jena, Germany
| | - K Küsel
- Aquatic Geomicrobiology, Institute of Ecology, Friedrich Schiller University Jena, Dornburger Strasse 159, 07743, Jena, Germany
- German Center for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Deutscher Platz 5e, 04103, Leipzig, Germany
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31
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Li J, Li D, Cui Y, Xing W, Deng S. Micro-electrolysis/retinervus luffae-based simultaneous autotrophic and heterotrophic denitrification for low C/N wastewater treatment. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2017; 24:16651-16658. [PMID: 28560622 DOI: 10.1007/s11356-017-9179-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Accepted: 05/01/2017] [Indexed: 06/07/2023]
Abstract
Nitrogen bioremediation in organic insufficient wastewater generally requires an extra carbon source. In this study, nitrate-contaminated wastewater was treated effectively through simultaneous autotrophic and heterotrophic denitrification based on micro-electrolysis carriers (MECs) and retinervus luffae fructus (RLF), respectively. The average nitrate and total nitrogen removal rates reached 96.3 and 94.0% in the MECs/RLF-based autotrophic and heterotrophic denitrification (MRAHD) system without ammonia and nitrite accumulation. The performance of MRAHD was better than that of MEC-based autotrophic denitrification for the wastewater treatment with low carbon nitrogen (COD/N) ratio. Real-time quantitative polymerase chain reaction (qPCR) revealed that the relative abundance of nirS-type denitrifiers attached to MECs (4.9%) and RLF (5.0%) was similar. Illumina sequencing suggested that the dominant genera were Thiobacillus (7.0%) and Denitratisoma (5.7%), which attached to MECs and RLF, respectively. Sulfuritalea was discovered as the dominant genus in the middle of the reactor. The synergistic interaction between autotrophic and heterotrophic denitrifiers played a vital role in the mixotrophic substrate environment.
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Affiliation(s)
- Jinlong Li
- School of Civil Engineering, Beijing Jiaotong University, Beijing, People's Republic of China
- Beijing Key Laboratory of Aqueous Typical Pollutants Control and Water Quality Safeguard, Beijing, People's Republic of China
| | - Desheng Li
- School of Civil Engineering, Beijing Jiaotong University, Beijing, People's Republic of China.
- Beijing Key Laboratory of Aqueous Typical Pollutants Control and Water Quality Safeguard, Beijing, People's Republic of China.
| | - Yuwei Cui
- School of Civil Engineering, Beijing Jiaotong University, Beijing, People's Republic of China
| | - Wei Xing
- School of Civil Engineering, Beijing Jiaotong University, Beijing, People's Republic of China
- Beijing Key Laboratory of Aqueous Typical Pollutants Control and Water Quality Safeguard, Beijing, People's Republic of China
| | - Shihai Deng
- School of Civil Engineering, Beijing Jiaotong University, Beijing, People's Republic of China
- Beijing Key Laboratory of Aqueous Typical Pollutants Control and Water Quality Safeguard, Beijing, People's Republic of China
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32
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Liu Y, Liu C, Nelson WC, Shi L, Xu F, Liu Y, Yan A, Zhong L, Thompson C, Fredrickson JK, Zachara JM. Effect of Water Chemistry and Hydrodynamics on Nitrogen Transformation Activity and Microbial Community Functional Potential in Hyporheic Zone Sediment Columns. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:4877-4886. [PMID: 28391700 DOI: 10.1021/acs.est.6b05018] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Hyporheic zones (HZ) are active biogeochemical regions where groundwater and surface water mix. N transformations in HZ sediments were investigated in columns with a focus on understanding how the dynamic changes in groundwater and surface water mixing affect microbial community and its biogeochemical function with respect to N transformations. The results indicated that denitrification, DNRA, and nitrification rates and products changed quickly in response to changes in water and sediment chemistry, fluid residence time, and groundwater-surface water exchange. These changes were accompanied by the zonation of denitrification functional genes along a 30 cm advective flow path after a total of 6 days' elution of synthetic groundwater with fluid residence time >9.8 h. The shift of microbial functional potential toward denitrification was correlated with rapid NO3- reduction collectively affected by NO3- concentration and fluid residence time, and was resistant to short-term groundwater-surface water exchange on a daily basis. The results implied that variations in microbial functional potential and associated biogeochemical reactions in the HZ may occur at space scales where steep concentration gradients present along the flow path and the variations would respond to dynamic HZ water exchange over different time periods common to natural and managed riverine systems.
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Affiliation(s)
- Yuanyuan Liu
- Pacific Northwest National Laboratory , Richland, Washington 99354, United States
- School of Earth Sciences and Engineering, Nanjing University , Nanjing, Jiangsu 210023, China
| | - Chongxuan Liu
- Pacific Northwest National Laboratory , Richland, Washington 99354, United States
- School of Environmental Science and Engineering, Southern University of Science and Technology , Shenzhen, Guangzhou 518055, China
| | - William C Nelson
- Pacific Northwest National Laboratory , Richland, Washington 99354, United States
| | - Liang Shi
- Pacific Northwest National Laboratory , Richland, Washington 99354, United States
- School of Environmental Studies, China University of Geosciences , Wuhan, Hubei 430074, China
| | - Fen Xu
- Pacific Northwest National Laboratory , Richland, Washington 99354, United States
- School of Environmental Studies, China University of Geosciences , Wuhan, Hubei 430074, China
| | - Yunde Liu
- Pacific Northwest National Laboratory , Richland, Washington 99354, United States
- School of Environmental Studies, China University of Geosciences , Wuhan, Hubei 430074, China
| | - Ailan Yan
- Pacific Northwest National Laboratory , Richland, Washington 99354, United States
- Institute of Hydraulic and Environmental Engineering, Zhejiang University of Water Resources and Electric Power , Hangzhou, Zhejiang 310018, China
| | - Lirong Zhong
- Pacific Northwest National Laboratory , Richland, Washington 99354, United States
| | - Christopher Thompson
- Pacific Northwest National Laboratory , Richland, Washington 99354, United States
| | - James K Fredrickson
- Pacific Northwest National Laboratory , Richland, Washington 99354, United States
| | - John M Zachara
- Pacific Northwest National Laboratory , Richland, Washington 99354, United States
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Saarenheimo J, Aalto SL, Rissanen AJ, Tiirola M. Microbial Community Response on Wastewater Discharge in Boreal Lake Sediments. Front Microbiol 2017; 8:750. [PMID: 28487691 PMCID: PMC5403825 DOI: 10.3389/fmicb.2017.00750] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Accepted: 04/12/2017] [Indexed: 12/27/2022] Open
Abstract
Despite high performance, municipal wastewater treatment plants (WWTPs) still discharge significant amounts of organic material and nitrogen and even microbes into the receiving water bodies, altering physico-chemical conditions and microbial functions. In this study, we examined how nitrified wastewater affects the microbiology of boreal lake sediments. Microbial community compositions were assessed with next generation sequencing of the 16S rRNA gene, and a more detailed view on nitrogen transformation processes was gained with qPCR targeting on functional genes (nirS, nirK, nosZI, nosZII, amoAarchaea, and amoAbacteria). In both of the two studied lake sites, the microbial community composition differed significantly between control point and wastewater discharge point, and a gradual shift toward natural community composition was seen downstream following the wastewater gradient. SourceTracker analysis predicted that ∼2% of sediment microbes were of WWTP-origin on the study site where wastewater was freely mixed with the lake water, while when wastewater was specially discharged to the sediment surface, ∼6% of microbes originated from WWTP, but the wastewater-influenced area was more limited. In nitrogen transformation processes, the ratio between nitrifying archaea (AOA) and bacteria (AOB) was affected by wastewater effluent, as the AOA abundance decreased from the control point (AOA:AOB 28:1 in Keuruu, 11:1 in Petäjävesi) to the wastewater-influenced sampling points, where AOB dominated (AOA:AOB 1:2–1:15 in Keuruu, 1:3–1:19 in Petäjävesi). The study showed that wastewater can affect sediment microbial community through importing nutrients and organic material and altering habitat characteristics, but also through bringing wastewater-originated microbes to the sediment, and may thus have significant impact on the freshwater biogeochemistry, especially in the nutrient-poor boreal ecosystems.
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Affiliation(s)
- Jatta Saarenheimo
- Department of Biological and Environmental Science, University of JyväskyläJyväskylä, Finland
| | - Sanni L Aalto
- Department of Biological and Environmental Science, University of JyväskyläJyväskylä, Finland
| | - Antti J Rissanen
- Laboratory of Chemistry and Bioengineering, Tampere University of TechnologyTampere, Finland
| | - Marja Tiirola
- Department of Biological and Environmental Science, University of JyväskyläJyväskylä, Finland
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Highton MP, Roosa S, Crawshaw J, Schallenberg M, Morales SE. Physical Factors Correlate to Microbial Community Structure and Nitrogen Cycling Gene Abundance in a Nitrate Fed Eutrophic Lagoon. Front Microbiol 2016; 7:1691. [PMID: 27826296 PMCID: PMC5078687 DOI: 10.3389/fmicb.2016.01691] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Accepted: 10/10/2016] [Indexed: 12/04/2022] Open
Abstract
Nitrogenous run-off from farmed pastures contributes to the eutrophication of Lake Ellesmere, a large shallow lagoon/lake on the east coast of New Zealand. Tributaries periodically deliver high loads of nitrate to the lake which likely affect microbial communities therein. We hypothesized that a nutrient gradient would form from the potential sources (tributaries) creating a disturbance resulting in changes in microbial community structure. To test this we first determined the existence of such a gradient but found only a weak nitrogen (TN) and phosphorous gradient (DRP). Changes in microbial communities were determined by measuring functional potential (quantification of nitrogen cycling genes via nifH, nirS, nosZI, and nosZII using qPCR), potential activity (via denitrification enzyme activity), as well as using changes in total community (via 16S rRNA gene amplicon sequencing). Our results demonstrated that changes in microbial communities at a phylogenetic (relative abundance) and functional level (proportion of the microbial community carrying nifH and nosZI genes) were most strongly associated with physical gradients (e.g., lake depth, sediment grain size, sediment porosity) and not nutrient concentrations. Low nitrate influx at the time of sampling is proposed as a factor contributing to the observed patterns.
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Affiliation(s)
- Matthew P Highton
- Department of Microbiology and Immunology, Otago School of Medical Sciences, University of Otago Dunedin, New Zealand
| | - Stéphanie Roosa
- Department of Microbiology and Immunology, Otago School of Medical Sciences, University of Otago Dunedin, New Zealand
| | - Josie Crawshaw
- Department of Marine Science, University of Otago Dunedin, New Zealand
| | | | - Sergio E Morales
- Department of Microbiology and Immunology, Otago School of Medical Sciences, University of Otago Dunedin, New Zealand
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Palmer K, Köpp J, Gebauer G, Horn MA. Drying-Rewetting and Flooding Impact Denitrifier Activity Rather than Community Structure in a Moderately Acidic Fen. Front Microbiol 2016; 7:727. [PMID: 27313566 PMCID: PMC4887476 DOI: 10.3389/fmicb.2016.00727] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Accepted: 05/02/2016] [Indexed: 02/04/2023] Open
Abstract
Wetlands represent sources or sinks of the greenhouse gas nitrous oxide (N2O). The acidic fen Schlöppnerbrunnen emits denitrification derived N2O and is also capable of N2O consumption. Global warming is predicted to cause more extreme weather events in future years, including prolonged drought periods as well as heavy rainfall events, which may result in flooding. Thus, the effects of prolonged drought and flooding events on the abundance, community composition, and activity of fen denitrifiers were investigated in manipulation experiments. The water table in the fen was experimentally lowered for 8 weeks in 2008 and raised for 5.5 months in 2009 on three treatment plots, while three plots were left untreated and served as controls. In situ N2O fluxes were rather unaffected by the drought treatment and were marginally increased by the flooding treatment. Samples were taken before and after treatment in both years. The structural gene markers narG and nosZ were used to assess possible changes in the nitrate reducer and denitrifier community in response to water table manipulations. Detected copy numbers of narG and nosZ were essentially unaffected by the experimental drought and flooding. Terminal restriction fragment length polymorphism (TRFLP) patterns of narG and nosZ were similar before and after experimental drought or experimental flooding, indicating a stable nitrate reducer and denitrifier community in the fen. However, certain TRFs of narG and nosZ transcripts responded to experimental drought or flooding. Nitrate-dependent Michaelis-Menten kinetics were assessed in anoxic microcosms with peat samples taken before and 6 months after the onset of experimental flooding. Maximal reaction velocities vmax were higher after than before flooding in samples from treament but not in those from control plots taken at the same time. The ratio of N2O to N2O + N2 was lower in soil from treatment plots after flooding than in soil from control plots, suggesting mitigation of N2O emissions by increased N2O-reduction rates after flooding. N2O was consumed to subatmospheric levels in all microcosms after flooding. The collective data indicate that water table manipulations had only minor effects on in situ N2O fluxes, denitrifier abundance, and denitrifier community composition of the acidic fen, while active subpopulations of denitrifiers changed in response to water table manipulations, suggesting functionally redundant subpopulations occupying distinct ecological niches in the fen.
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Affiliation(s)
- Katharina Palmer
- Department of Ecological Microbiology, University of BayreuthBayreuth, Germany; Water Resources and Environmental Engineering Research Group, University of OuluOulu, Finland
| | - Julia Köpp
- BayCEER-Laboratory of Isotope Biogeochemistry, University of Bayreuth Bayreuth, Germany
| | - Gerhard Gebauer
- BayCEER-Laboratory of Isotope Biogeochemistry, University of Bayreuth Bayreuth, Germany
| | - Marcus A Horn
- Department of Ecological Microbiology, University of Bayreuth Bayreuth, Germany
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