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Li Q, Yu H, Yuan P, Liu R, Jing Z, Wei Y, Tu S, Gao H, Song Y. Mitigated N 2O emissions from submerged-plant-covered aquatic ecosystems on the Changjiang River Delta. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 928:172592. [PMID: 38642768 DOI: 10.1016/j.scitotenv.2024.172592] [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: 01/10/2024] [Revised: 04/14/2024] [Accepted: 04/17/2024] [Indexed: 04/22/2024]
Abstract
Submerged plants affect nitrogen cycling in aquatic ecosystems. However, whether and how submerged plants change nitrous oxide (N2O) production mechanism and emissions flux remains controversial. Current research primarily focuses on the feedback from N2O release to variation of substrate level and microbial communities. It is deficient in connecting the relative contribution of individual N2O production processes (i.e., the N2O partition). Here, we attempted to offer a comprehensive understanding of the N2O mitigation mechanism in aquatic ecosystems on the Changjiang River Delta according to stable isotopic techniques, metagenome-assembly genome analysis, and statistical analysis. We found that the submerged plant reduced 45 % of N2O emissions by slowing down the dissolved inorganic nitrogen conversion velocity to N2O in sediment (Vf-[DIN]sed). It was attributed to changing the N2O partition and suppressing the potential capacity of net N2O production (i.e., nor/nosZ). The dominated production processes showed a shift with increasing excess N2O. Meanwhile, distinct shift thresholds of planted and unplanted habitats reflected different mechanisms of stimulated N2O production. The hotspot zone of N2O production corresponded to high nor/nosZ and unsaturated oxygen (O2) in unplanted habitat. In contrast, planted habitat hotspot has lower nor/nosZ and supersaturated O2. O2 from photosynthesis critically impacted the activities of N2O producers and consumers. In summary, the presence of submerged plants is beneficial to mitigate N2O emissions from aquatic ecosystems.
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Affiliation(s)
- Qingqian Li
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Science, Beijing 100012, China; State Environmental Protection Key Laboratory of Estuarine and Coastal Environment, Chinese Research Academy of Environmental Science, Beijing 100012, China
| | - Huibin Yu
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Science, Beijing 100012, China
| | - Peng Yuan
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Science, Beijing 100012, China
| | - Ruixia Liu
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Science, Beijing 100012, China
| | - Zhangmu Jing
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Science, Beijing 100012, China; State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
| | - Yanjie Wei
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Science, Beijing 100012, China; College of Municipal and Environmental Engineering, Shenyang Jianzhu University, 110168, China
| | - Shengqiang Tu
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Science, Beijing 100012, China
| | - Hongjie Gao
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Science, Beijing 100012, China; State Environmental Protection Key Laboratory of Estuarine and Coastal Environment, Chinese Research Academy of Environmental Science, Beijing 100012, China.
| | - Yonghui Song
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Science, Beijing 100012, China
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Hu M, Yu Z, Griffis TJ, Yang WH, Mohn J, Millet DB, Baker JM, Wang D. Hydrologic Connectivity Regulates Riverine N 2O Sources and Dynamics. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:9701-9713. [PMID: 38780660 DOI: 10.1021/acs.est.4c01285] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2024]
Abstract
Indirect nitrous oxide (N2O) emissions from streams and rivers are a poorly constrained term in the global N2O budget. Current models of riverine N2O emissions place a strong focus on denitrification in groundwater and riverine environments as a dominant source of riverine N2O, but do not explicitly consider direct N2O input from terrestrial ecosystems. Here, we combine N2O isotope measurements and spatial stream network modeling to show that terrestrial-aquatic interactions, driven by changing hydrologic connectivity, control the sources and dynamics of riverine N2O in a mesoscale river network within the U.S. Corn Belt. We find that N2O produced from nitrification constituted a substantial fraction (i.e., >30%) of riverine N2O across the entire river network. The delivery of soil-produced N2O to streams was identified as a key mechanism for the high nitrification contribution and potentially accounted for more than 40% of the total riverine emission. This revealed large terrestrial N2O input implies an important climate-N2O feedback mechanism that may enhance riverine N2O emissions under a wetter and warmer climate. Inadequate representation of hydrologic connectivity in observations and modeling of riverine N2O emissions may result in significant underestimations.
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Affiliation(s)
- Minpeng Hu
- Department of Natural Resources and Environmental Sciences, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
- College of Environmental & Resource Sciences, Zhejiang University, Hangzhou 310058, People's Republic of China
| | - Zhongjie Yu
- Department of Natural Resources and Environmental Sciences, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Timothy J Griffis
- Department of Soil, Water, and Climate, University of Minnesota─Twin Cities, St. Paul, Minnesota 55108, United States
| | - Wendy H Yang
- Department of Plant Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
- Department of Earth Science and Environmental Change, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Joachim Mohn
- Laboratory for Air Pollution & Environmental Technology, Empa, Dübendorf CH-8600, Switzerland
| | - Dylan B Millet
- Department of Soil, Water, and Climate, University of Minnesota─Twin Cities, St. Paul, Minnesota 55108, United States
| | - John M Baker
- Department of Soil, Water, and Climate, University of Minnesota─Twin Cities, St. Paul, Minnesota 55108, United States
- Agricultural Research Service, United States Department of Agriculture, St. Paul, Minnesota 55108, United States
| | - Dongqi Wang
- School of Geographical Sciences, Key Laboratory of Geographic Information Science (Ministry of Education), East China Normal University, Shanghai 200241, People's Republic of China
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Deb S, Lewicka-Szczebak D, Rohe L. Microbial nitrogen transformations tracked by natural abundance isotope studies and microbiological methods: A review. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 926:172073. [PMID: 38554959 DOI: 10.1016/j.scitotenv.2024.172073] [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: 01/03/2024] [Revised: 03/07/2024] [Accepted: 03/27/2024] [Indexed: 04/02/2024]
Abstract
Nitrogen is an essential nutrient in the environment that exists in multiple oxidation states in nature. Numerous microbial processes are involved in its transformation. Knowledge about very complex N cycling has been growing rapidly in recent years, with new information about associated isotope effects and about the microbes involved in particular processes. Furthermore, molecular methods that are able to detect and quantify particular processes are being developed, applied and combined with other analytical approaches, which opens up new opportunities to enhance understanding of nitrogen transformation pathways. This review presents a summary of the microbial nitrogen transformation, including the respective isotope effects of nitrogen and oxygen on different nitrogen-bearing compounds (including nitrates, nitrites, ammonia and nitrous oxide), and the microbiological characteristics of these processes. It is supplemented by an overview of molecular methods applied for detecting and quantifying the activity of particular enzymes involved in N transformation pathways. This summary should help in the planning and interpretation of complex research studies applying isotope analyses of different N compounds and combining microbiological and isotopic methods in tracking complex N cycling, and in the integration of these results in modelling approaches.
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Affiliation(s)
- Sushmita Deb
- Institute of Geological Sciences, University of Wrocław, pl. M. Borna 9, 50-204 Wrocław, Poland
| | | | - Lena Rohe
- Thünen Institute of Climate-Smart Agriculture, Bundesallee 65, 38116 Braunschweig, Germany
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4
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Chen W, Zhang X, Wu N, Yuan C, Liu Y, Yang Y, Chen Z, Dahlgren RA, Zhang M, Ji X. Sources and transformations of riverine nitrogen across a coastal-plain river network of eastern China: New insights from multiple stable isotopes. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 924:171671. [PMID: 38479520 DOI: 10.1016/j.scitotenv.2024.171671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Revised: 03/10/2024] [Accepted: 03/10/2024] [Indexed: 03/18/2024]
Abstract
Riverine nitrogen pollution is ubiquitous and attracts considerable global attention. Nitrate is commonly the dominant total nitrogen (TN) constituent in surface and ground waters; thus, stable isotopes of nitrate (δ15N/δ18O-NO3-) are widely used to differentiate nitrate sources. However, δ15N/δ18O-NO3- approach fails to present a holistic perspective of nitrogen pollution for many coastal-plain river networks because diverse nitrogen species contribute to high TN loads. In this study, multiple isotopes, namely, δ15N/δ18O-NO3-, δ18O-H2O, δ15N-NH4+, δ15N-PN, and δ15Nbulk/δ18O/SP-N2O in the Wen-Rui Tang River, a typical coastal-plain river network of Eastern China, were investigated to identify transformation processes and sources of nitrogen. Then, a stable isotope analysis in R (SIAR) model-TN source apportionment method was developed to quantify the contributions of different nitrogen sources to riverine TN loads. Results showed that nitrogen pollution in the river network was serious with TN concentrations ranging from 1.71 to 8.09 mg/L (mean ± SD: 3.77 ± 1.39 mg/L). Ammonium, nitrate, and suspended particulate nitrogen were the most prominent nitrogen components during the study period, constituting 45.4 %, 28.9 %, and 19.9 % of TN, respectively. Multiple hydrochemical and isotopic analysis identified nitrification as the dominant N cycling process. Biological assimilation and denitrification were minor N cycling processes, whereas ammonia volatilization was deemed negligible. Isotopic evidence and SIAR modeling revealed municipal sewage was the dominant contributor to nitrogen pollution. Based on quantitative estimates from the SIAR model, nitrogen source contributions to the Wen-Rui Tang River watershed followed: municipal sewage (40.6 %) ≈ soil nitrogen (39.5 %) > nitrogen fertilizer (9.7 %) > atmospheric deposition (2.8 %) during wet season; and municipal sewage (59.1 %) > soil nitrogen (30.4 %) > nitrogen fertilizer (4.1 %) > atmospheric deposition (1.0 %) during dry season. This study provides a deeper understanding of nitrogen dynamics in eutrophic coastal-plain river networks, which informs strategies for efficient control and remediation of riverine nitrogen pollution.
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Affiliation(s)
- Wenli Chen
- Key Laboratory of Watershed Science and Health of Zhejiang Province, School of Public Health and Management, Wenzhou Medical University, Wenzhou 325035, China
| | - Xiaohan Zhang
- Zhejiang Provincial Key Laboratory for Water Environment and Marine Biological Resources Protection, College of Life and Environmental Science, Wenzhou University, Wenzhou 325035, China
| | - Nianting Wu
- Zhejiang Provincial Key Laboratory for Water Environment and Marine Biological Resources Protection, College of Life and Environmental Science, Wenzhou University, Wenzhou 325035, China
| | - Can Yuan
- Zhejiang Provincial Key Laboratory for Water Environment and Marine Biological Resources Protection, College of Life and Environmental Science, Wenzhou University, Wenzhou 325035, China
| | - Yinli Liu
- Key Laboratory of Watershed Science and Health of Zhejiang Province, School of Public Health and Management, Wenzhou Medical University, Wenzhou 325035, China
| | - Yue Yang
- Zhejiang Provincial Key Laboratory for Water Environment and Marine Biological Resources Protection, College of Life and Environmental Science, Wenzhou University, Wenzhou 325035, China; Southern Zhejiang Water Research Institute, Wenzhou 325035, China
| | - Zheng Chen
- Key Laboratory of Watershed Science and Health of Zhejiang Province, School of Public Health and Management, Wenzhou Medical University, Wenzhou 325035, China
| | - Randy A Dahlgren
- Department of Land, Air and Water Resources, University of California, Davis, California 95616, USA
| | - Minghua Zhang
- Key Laboratory of Watershed Science and Health of Zhejiang Province, School of Public Health and Management, Wenzhou Medical University, Wenzhou 325035, China; Southern Zhejiang Water Research Institute, Wenzhou 325035, China; Department of Land, Air and Water Resources, University of California, Davis, California 95616, USA
| | - Xiaoliang Ji
- Key Laboratory of Watershed Science and Health of Zhejiang Province, School of Public Health and Management, Wenzhou Medical University, Wenzhou 325035, China.
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Li X, Qi M, Li Q, Wu B, Fu Y, Liang X, Yin G, Zheng Y, Dong H, Liu M, Hou L. Acidification Offset Warming-Induced Increase in N 2O Production in Estuarine and Coastal Sediments. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:4989-5002. [PMID: 38442002 DOI: 10.1021/acs.est.3c10691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/07/2024]
Abstract
Global warming and acidification, induced by a substantial increase in anthropogenic CO2 emissions, are expected to have profound impacts on biogeochemical cycles. However, underlying mechanisms of nitrous oxide (N2O) production in estuarine and coastal sediments remain rarely constrained under warming and acidification. Here, the responses of sediment N2O production pathways to warming and acidification were examined using a series of anoxic incubation experiments. Denitrification and N2O production were largely stimulated by the warming, while N2O production decreased under the acidification as well as the denitrification rate and electron transfer efficiency. Compared to warming alone, the combination of warming and acidification decreased N2O production by 26 ± 4%, which was mainly attributed to the decline of the N2O yield by fungal denitrification. Fungal denitrification was mainly responsible for N2O production under the warming condition, while bacterial denitrification predominated N2O production under the acidification condition. The reduced site preference of N2O under acidification reflects that the dominant pathways of N2O production were likely shifted from fungal to bacterial denitrification. In addition, acidification decreased the diversity and abundance of nirS-type denitrifiers, which were the keystone taxa mediating the low N2O production. Collectively, acidification can decrease sediment N2O yield through shifting the responsible production pathways, partly counteracting the warming-induced increase in N2O emissions, further reducing the positive climate warming feedback loop.
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Affiliation(s)
- Xiaofei Li
- State Key Laboratory of Estuarine and Coastal Research, Yangtze Delta Estuarine Wetland Ecosystem Observation and Research Station, Ministry of Education & Shanghai, East China Normal University, Shanghai 200241, China
- Key Laboratory of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai 200241, China
| | - Mengting Qi
- Key Laboratory of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai 200241, China
| | - Qiuxuan Li
- Key Laboratory of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai 200241, China
| | - Boshuang Wu
- State Key Laboratory of Estuarine and Coastal Research, Yangtze Delta Estuarine Wetland Ecosystem Observation and Research Station, Ministry of Education & Shanghai, East China Normal University, Shanghai 200241, China
| | - Yuxuan Fu
- State Key Laboratory of Estuarine and Coastal Research, Yangtze Delta Estuarine Wetland Ecosystem Observation and Research Station, Ministry of Education & Shanghai, East China Normal University, Shanghai 200241, China
| | - Xia Liang
- State Key Laboratory of Estuarine and Coastal Research, Yangtze Delta Estuarine Wetland Ecosystem Observation and Research Station, Ministry of Education & Shanghai, East China Normal University, Shanghai 200241, China
| | - Guoyu Yin
- Key Laboratory of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai 200241, China
| | - Yanling Zheng
- Key Laboratory of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai 200241, China
| | - Hongpo Dong
- State Key Laboratory of Estuarine and Coastal Research, Yangtze Delta Estuarine Wetland Ecosystem Observation and Research Station, Ministry of Education & Shanghai, East China Normal University, Shanghai 200241, China
| | - Min Liu
- Key Laboratory of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai 200241, China
| | - Lijun Hou
- State Key Laboratory of Estuarine and Coastal Research, Yangtze Delta Estuarine Wetland Ecosystem Observation and Research Station, Ministry of Education & Shanghai, East China Normal University, Shanghai 200241, China
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6
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Nishina K, Melling L, Toyoda S, Itoh M, Terajima K, Waili JWB, Wong GX, Kiew F, Aeries EB, Hirata R, Takahashi Y, Onodera T. Dissolved N 2O concentrations in oil palm plantation drainage in a peat swamp of Malaysia. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 872:162062. [PMID: 36804973 DOI: 10.1016/j.scitotenv.2023.162062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2022] [Revised: 01/30/2023] [Accepted: 02/02/2023] [Indexed: 06/18/2023]
Abstract
Oil palm plantations in Southeast Asia are the largest supplier of palm oil products and have been rapidly expanding in the last three decades even in peat-swamp areas. Oil palm plantations on peat ecosystems have a unique water management system that lowers the water table and, thus, may yield indirect N2O emissions from the peat drainage system. We conducted two seasons of spatial monitoring for the dissolved N2O concentrations in the drainage and adjacent rivers of palm oil plantations on peat swamps in Sarawak, Malaysia, to evaluate the magnitude of indirect N2O emissions from this ecosystem. In both the dry and wet seasons, the mean and median dissolved N2O concentrations exhibited over-saturation in the drainage water, i.e., the oil palm plantation drainage may be a source of N2O to the atmosphere. In the wet season, the spatial distribution of dissolved N2O showed bimodal peaks in both the unsaturated and over-saturated concentrations. The bulk δ15N of dissolved N2O was higher than the source of inorganic N in the oil palm plantation (i.e., N fertilizer and soil organic nitrogen) during both seasons. An isotopocule analysis of the dissolved N2O suggested that denitrification was a major source of N2O, followed by N2O reduction processes that occurred in the drainage water. The δ15N and site preference mapping analysis in dissolved N2O revealed that a significant proportion of the N2O produced in peat and drainage is reduced to N2 before being released into the atmosphere.
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Affiliation(s)
- Kazuya Nishina
- Earth System Division, National Institute for Environmental Studies, 16-2, Onogawa, Tsukuba, Ibaraki 305-8506, Japan.
| | - Lulie Melling
- Sarawak Tropical Peat Research Institute, Lot 6035, Kota Samarahan Expressway, Kuching, Sarawak 94300, Malaysia
| | - Sakae Toyoda
- Department of Chemical Science and Engineering, School of Materials and Chemical Technology, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama, Kanagawa 226-8502, Japan
| | - Masayuki Itoh
- School of Human Science and Environment, University of Hyogo, 1-1-12, Shinzaike-honcho, Himeji, Hyogo 670-0092, Japan
| | - Kotaro Terajima
- Department of Chemical Science and Engineering, School of Materials and Chemical Technology, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama, Kanagawa 226-8502, Japan
| | - Joseph W B Waili
- Sarawak Tropical Peat Research Institute, Lot 6035, Kota Samarahan Expressway, Kuching, Sarawak 94300, Malaysia
| | - Guan X Wong
- Sarawak Tropical Peat Research Institute, Lot 6035, Kota Samarahan Expressway, Kuching, Sarawak 94300, Malaysia
| | - Frankie Kiew
- Sarawak Tropical Peat Research Institute, Lot 6035, Kota Samarahan Expressway, Kuching, Sarawak 94300, Malaysia
| | - Edward B Aeries
- Sarawak Tropical Peat Research Institute, Lot 6035, Kota Samarahan Expressway, Kuching, Sarawak 94300, Malaysia
| | - Ryuichi Hirata
- Earth System Division, National Institute for Environmental Studies, 16-2, Onogawa, Tsukuba, Ibaraki 305-8506, Japan
| | - Yoshiyuki Takahashi
- Earth System Division, National Institute for Environmental Studies, 16-2, Onogawa, Tsukuba, Ibaraki 305-8506, Japan
| | - Takashi Onodera
- Earth System Division, National Institute for Environmental Studies, 16-2, Onogawa, Tsukuba, Ibaraki 305-8506, Japan
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Li X, Gao D, Li Y, Zheng Y, Dong H, Liang X, Liu M, Hou L. Increased Nitrogen Loading Facilitates Nitrous Oxide Production through Fungal and Chemodenitrification in Estuarine and Coastal Sediments. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:2660-2671. [PMID: 36734984 DOI: 10.1021/acs.est.2c06602] [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] [Indexed: 06/18/2023]
Abstract
Estuarine and coastal environments are assumed to contribute to nitrous oxide (N2O) emissions under increasing nitrogen loading. However, isotopic and molecular mechanisms underlying N2O production pathways under elevated nitrogen concentration remain poorly understood. Here we used microbial inhibition, isotope mass balance, and molecular approaches to investigate N2O production mechanisms in estuarine and coastal sediments through a series of anoxic incubations. Site preference of the N2O molecule increased due to increasing nitrate concentration, suggesting the changes in N2O production pathways. Enhanced N2O production under high nitrate concentration was not mediated by bacterial denitrification, but instead was mainly regulated by fungal denitrification. Elevated nitrate concentration increased the contribution of fungal denitrification to N2O production by 11-25%, whereas it decreased bacterial N2O production by 16-33%. Chemodenitrification was also enhanced by high nitrate concentration, contributing to 13-28% of N2O production. Elevated nitrate concentration significantly mediated nirK-type denitrifiers structure and abundance, which are the keystone taxa driving N2O production. Collectively, these results suggest that increasing nitrate concentration can shift N2O production pathways from bacterial to fungal and chemodenitrification, which are mainly responsible for the enhanced N2O production and have widespread implications for N2O projections under ongoing nitrogen pollution in estuarine and coastal ecosystems.
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Affiliation(s)
- Xiaofei Li
- State Key Laboratory of Estuarine and Coastal Research, Yangtze Delta Estuarine Wetland Ecosystem Observation and Research Station, Ministry of Education & Shanghai, East China Normal University, Shanghai200241, China
- Key Laboratory of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai200241, China
| | - Dengzhou Gao
- State Key Laboratory of Estuarine and Coastal Research, Yangtze Delta Estuarine Wetland Ecosystem Observation and Research Station, Ministry of Education & Shanghai, East China Normal University, Shanghai200241, China
| | - Ye Li
- Key Laboratory of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai200241, China
| | - Yanling Zheng
- Key Laboratory of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai200241, China
| | - Hongpo Dong
- State Key Laboratory of Estuarine and Coastal Research, Yangtze Delta Estuarine Wetland Ecosystem Observation and Research Station, Ministry of Education & Shanghai, East China Normal University, Shanghai200241, China
| | - Xia Liang
- State Key Laboratory of Estuarine and Coastal Research, Yangtze Delta Estuarine Wetland Ecosystem Observation and Research Station, Ministry of Education & Shanghai, East China Normal University, Shanghai200241, China
| | - Min Liu
- Key Laboratory of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai200241, China
| | - Lijun Hou
- State Key Laboratory of Estuarine and Coastal Research, Yangtze Delta Estuarine Wetland Ecosystem Observation and Research Station, Ministry of Education & Shanghai, East China Normal University, Shanghai200241, China
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Karlowsky S, Buchen-Tschiskale C, Odasso L, Schwarz D, Well R. Sources of nitrous oxide emissions from hydroponic tomato cultivation: Evidence from stable isotope analyses. Front Microbiol 2023; 13:1080847. [PMID: 36687587 PMCID: PMC9845576 DOI: 10.3389/fmicb.2022.1080847] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Accepted: 12/06/2022] [Indexed: 01/06/2023] Open
Abstract
Introduction Hydroponic vegetable cultivation is characterized by high intensity and frequent nitrogen fertilizer application, which is related to greenhouse gas emissions, especially in the form of nitrous oxide (N2O). So far, there is little knowledge about the sources of N2O emissions from hydroponic systems, with the few studies indicating that denitrification could play a major role. Methods Here, we use evidence from an experiment with tomato plants (Solanum lycopersicum) grown in a hydroponic greenhouse setup to further shed light into the process of N2O production based on the N2O isotopocule method and the 15N tracing approach. Gas samples from the headspace of rock wool substrate were collected prior to and after 15N labeling at two occasions using the closed chamber method and analyzed by gas chromatography and stable isotope ratio mass spectrometry. Results The isotopocule analyses revealed that either heterotrophic bacterial denitrification (bD) or nitrifier denitrification (nD) was the major source of N2O emissions, when a typical nutrient solution with a low ammonium concentration (1-6 mg L-1) was applied. Furthermore, the isotopic shift in 15N site preference and in δ18O values indicated that approximately 80-90% of the N2O produced were already reduced to N2 by denitrifiers inside the rock wool substrate. Despite higher concentrations of ammonium present during the 15N labeling (30-60 mg L-1), results from the 15N tracing approach showed that N2O mainly originated from bD. Both, 15N label supplied in the form of ammonium and 15N label supplied in the form of nitrate, increased the 15N enrichment of N2O. This pointed to the contribution of other processes than bD. Nitrification activity was indicated by the conversion of small amounts of 15N-labeled ammonium into nitrate. Discussion/Conclusion Comparing the results from N2O isotopocule analyses and the 15N tracing approach, likely a combination of bD, nD, and coupled nitrification and denitrification (cND) was responsible for the vast part of N2O emissions observed in this study. Overall, our findings help to better understand the processes underlying N2O and N2 emissions from hydroponic tomato cultivation, and thereby facilitate the development of targeted N2O mitigation measures.
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Affiliation(s)
- Stefan Karlowsky
- Leibniz Institute of Vegetable and Ornamental Crops (IGZ) e.V., Großbeeren, Germany,*Correspondence: Stefan Karlowsky, ✉
| | - Caroline Buchen-Tschiskale
- Thünen Institute of Climate-Smart Agriculture, Federal Research Institute for Rural Areas, Forestry and Fisheries, Braunschweig, Germany
| | - Luca Odasso
- Leibniz Institute of Vegetable and Ornamental Crops (IGZ) e.V., Großbeeren, Germany
| | - Dietmar Schwarz
- Leibniz Institute of Vegetable and Ornamental Crops (IGZ) e.V., Großbeeren, Germany,Operation Mercy, Amman, Jordan
| | - Reinhard Well
- Thünen Institute of Climate-Smart Agriculture, Federal Research Institute for Rural Areas, Forestry and Fisheries, Braunschweig, Germany
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9
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Li S, Wang S, Ji G. Influences of carbon sources on N 2O production during denitrification in freshwaters: Activity, isotopes and functional microbes. WATER RESEARCH 2022; 226:119315. [PMID: 36369690 DOI: 10.1016/j.watres.2022.119315] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2022] [Revised: 08/15/2022] [Accepted: 10/29/2022] [Indexed: 06/16/2023]
Abstract
Denitrification is one of the major sources of N2O in freshwaters. Diverse forms of organic compounds act as the electron donors for microbial denitrification. However, the influences of carbon sources on N2O production, N2O reduction, isotope fractionation and functional microbes during denitrification were largely unknown. In this study, five forms of carbon sources (i.e. acetate, citrate, glucose, cellobiose and leucine) were used to enrich denitrifiers in freshwater sediments. N2O conversion in the enrichments was investigated by a combination of inhibition technique, natural stable isotope method and metagenomics. Acetylene was effective in inhibiting N2O reduction without influencing the isotopic characteristics during N2O production. Glucose led to the least N2O production and reduction, in accordance with the lowest abundance of both NO and N2O reductases in this enrichment. δ18O and site preference value (SP, =δ15Nα-δ15Nβ) of N2O were sensitive to discriminate the five carbon sources, except when comparing acetate and leucine. Isotopic values of N2O were not significantly different in these two enrichments due to the similarity of NO reductases - Pseudomonas-type cNorB. Specifically, the enrichment with cellobiose produced N2O with the lowest δ18O values (39.4‰±1.1‰), due to Alicycliphilus with both cNorB and qNorB. The enrichment with glucose led to the highest SP values (8.9‰±8.6‰), caused by Thiobacillus-type cNorB. Our results demonstrated the link between carbon sources, N2O production and reduction, isotopic signatures, microbial populations and enzymes during denitrification in freshwaters.
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Affiliation(s)
- Shengjie Li
- Key Laboratory of Water and Sediment Sciences, Ministry of Education, Department of Environmental Engineering, Peking University, Beijing 100871, China
| | - Shuo Wang
- Key Laboratory of Water and Sediment Sciences, Ministry of Education, Department of Environmental Engineering, Peking University, Beijing 100871, China
| | - Guodong Ji
- Key Laboratory of Water and Sediment Sciences, Ministry of Education, Department of Environmental Engineering, Peking University, Beijing 100871, China.
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10
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Su X, Cui L, Tang Y, Wen T, Yang K, Wang Y, Zhang J, Zhu G, Yang X, Hou L, Zhu YG. Denitrification and N 2O Emission in Estuarine Sediments in Response to Ocean Acidification: From Process to Mechanism. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:14828-14839. [PMID: 36194569 DOI: 10.1021/acs.est.2c03550] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Global estuarine ecosystems are experiencing severe nitrogen pollution and ocean acidification (OA) simultaneously. Sedimentary denitrification is an important way of reactive nitrogen removal but at the same time leads to the emission of large amounts of nitrous oxide (N2O), a potent greenhouse gas. It is known that OA in estuarine regions could impact denitrification and N2O production; however, the underlying mechanism is still underexplored. Here, sediment incubation and pure culture experiments were conducted to explore the OA impacts on microbial denitrification and the associated N2O emissions in estuarine sediments. Under neutral (in situ) conditions, fungal N2O emission dominated in the sediment, while the bacterial and fungal sources had a similar role under acidification. This indicated that acidification decreased the sedimentary fungal denitrification and likely inhibited the activity of fungal denitrifiers. To explore molecular mechanisms, a denitrifying fungal strain of Penicillium janthinellum was isolated from the sediments. By using deuterium-labeled single-cell Raman spectroscopy and isobaric tags for relative and absolute quantitation proteomics, we found that acidification inhibited electron transfers in P. janthinellum and downregulated expressions of the proteins related to energy production and conservation. Two collaborative pathways of energy generation in the P. janthinellum were further revealed, that is, aerobic oxidative phosphorylation and TCA cycle and anoxic pyruvate fermentation. This indicated a distinct energy supply strategy from bacterial denitrification. Our study provides insights into fungi-mediated nitrogen cycle in acidifying aquatic ecosystems.
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Affiliation(s)
- Xiaoxuan Su
- Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen361021, China
- Interdisciplinary Research Center for Agriculture Green Development in Yangtze River Basin, College of Resources and Environment; Key Laboratory of Low-Carbon Green Agriculture in Southwestern China, Ministry of Agriculture and Rural Affairs, Southwest University, Chongqing400715, China
| | - Li Cui
- Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen361021, China
| | - Yijia Tang
- School of Life and Environmental Sciences, The University of Sydney, Biomedical Building (C81), Sydney, New South Wales2015, Australia
| | - Teng Wen
- School of Geography, Nanjing Normal University, Nanjing210023, China
- Key Laboratory of Virtual Geographic Environment, Ministry of Education, Nanjing Normal University, Nanjing210023, China
| | - Kai Yang
- Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen361021, China
| | - Yingmu Wang
- College of Civil Engineering, Fuzhou University, Fuzhou350116, China
| | - Jinbo Zhang
- School of Geography, Nanjing Normal University, Nanjing210023, China
- Key Laboratory of Virtual Geographic Environment, Ministry of Education, Nanjing Normal University, Nanjing210023, China
| | - Guibing Zhu
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing100085, China
| | - Xiaoru Yang
- Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen361021, China
| | - Lijun Hou
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai200062, China
| | - Yong-Guan Zhu
- Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen361021, China
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing100085, China
- University of the Chinese Academy of Sciences, Beijing100049, China
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11
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Su X, Yang L, Yang K, Tang Y, Wen T, Wang Y, Rillig MC, Rohe L, Pan J, Li H, Zhu YG. Estuarine plastisphere as an overlooked source of N2O production. Nat Commun 2022; 13:3884. [PMID: 35794126 PMCID: PMC9259610 DOI: 10.1038/s41467-022-31584-x] [Citation(s) in RCA: 62] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Accepted: 06/22/2022] [Indexed: 12/13/2022] Open
Abstract
“Plastisphere”, microbial communities colonizing plastic debris, has sparked global concern for marine ecosystems. Microbiome inhabiting this novel human-made niche has been increasingly characterized; however, whether the plastisphere holds crucial roles in biogeochemical cycling remains largely unknown. Here we evaluate the potential of plastisphere in biotic and abiotic denitrification and nitrous oxide (N2O) production in estuaries. Biofilm formation provides anoxic conditions favoring denitrifiers. Comparing with surrounding bulk water, plastisphere exhibits a higher denitrifying activity and N2O production, suggesting an overlooked N2O source. Regardless of plastisphere and bulk water, bacterial and fungal denitrifications are the main regulators for N2O production instead of chemodenitrification. However, the contributions of bacteria and fungi in the plastisphere are different from those in bulk water, indicating a distinct N2O production pattern in the plastisphere. These findings pinpoint plastisphere as a N2O source, and provide insights into roles of the new biotope in biogeochemical cycling in the Anthropocene. The roles of marine plastisphere in global nitrogen cycling are largely unknown. Here, the authors indicate that the plastisphere could act as a potential source of N2O production, which is mainly regulated by the biotic denitrification
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12
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Liu H, Zeng W, Li J, Zhan M, Fan Z, Peng Y. Effect of S 2O 32--S addition on Anammox coupling sulfur autotrophic denitrification and mechanism analysis using N and O dual isotope effects. WATER RESEARCH 2022; 218:118404. [PMID: 35462259 DOI: 10.1016/j.watres.2022.118404] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Revised: 04/01/2022] [Accepted: 04/02/2022] [Indexed: 06/14/2023]
Abstract
Anaerobic ammonia oxidation (Anammox) coupling sulfur autotrophic denitrification is an effective method for the advanced nitrogen removal from the wastewater with limited carbon source. The influence of S2O32--S addition on Anammox coupling sulfur autotrophic denitrification was investigated by adding different concentrations of S2O32--S (0, 39, 78, 156 and 312 mg/L) to the Anammox system. The contribution of sulfur autotrophic denitrification and Anammox to nitrogen removal at S2O32--S concentrations of 156 mg/L was 75% ∼83% and 17%∼25%, respectively, and the mixed system achieved completely nitrogen removal. However, Anammox bioactivity was completely inhibited at S2O32--S concentrations up to 312 mg/L, and only sulfur autotrophic denitrification occurred. The isotopic effects of NO2--N (δ15NNO2 and δ18ONO2) and NO3--N (δ15NNO3 and δ18ONO3) during Anammox coupling sulfur autotrophic denitrification showed a gradual decrease trend with the increase of S2O32--S addition. The ratios of δ15NNO2:δ18ONO2 and δ15NNO3:δ18ONO3 was maintained at 1.30-2.41 and 1.36-2.52, respectively, which revealed that Anammox was dominant nitrogen removal pathway at S2O32--S concentrations less than 156 mg/L. Microbial diversity gradually decreased with the increase of S2O32--S. The S2O32--S addition enhanced the S2O32--driven autotrophic denitrification and weakened the Anammox, leading to a gradually decreasing trend of the proportion of Candidatus Brocadia as Anammox bacteria from the initial 27% to 4% (S2O32--S of 156 mg/L). Yet Norank-f-Hydrogenophilaceae (more than 50%) and Thiobacillus (54%) as functional bacteria of autotrophic denitrification obviously increased. The appropriate amount of S2O32--S addition promoted the performance of Anammox coupling sulfur autotrophic denitrification achieved completely nitrogen removal.
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Affiliation(s)
- Hong Liu
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Department of Environmental Engineering, Beijing University of Technology, No. 100 Pingleyuan, Chaoyang District, Beijing 100124, China
| | - Wei Zeng
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Department of Environmental Engineering, Beijing University of Technology, No. 100 Pingleyuan, Chaoyang District, Beijing 100124, China.
| | - Jianmin Li
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Department of Environmental Engineering, Beijing University of Technology, No. 100 Pingleyuan, Chaoyang District, Beijing 100124, China
| | - Mengjia Zhan
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Department of Environmental Engineering, Beijing University of Technology, No. 100 Pingleyuan, Chaoyang District, Beijing 100124, China
| | - Zhiwei Fan
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Department of Environmental Engineering, Beijing University of Technology, No. 100 Pingleyuan, Chaoyang District, Beijing 100124, China
| | - Yongzhen Peng
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Department of Environmental Engineering, Beijing University of Technology, No. 100 Pingleyuan, Chaoyang District, Beijing 100124, China
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13
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Kaushal R, Hsueh YH, Chen CL, Lan YP, Wu PY, Chen YC, Liang MC. Isotopic assessment of soil N 2O emission from a sub-tropical agricultural soil under varying N-inputs. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 827:154311. [PMID: 35257756 DOI: 10.1016/j.scitotenv.2022.154311] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2021] [Revised: 02/12/2022] [Accepted: 03/01/2022] [Indexed: 06/14/2023]
Abstract
Nitrogen fertilizers result in high crop productivity but also enhance the emission of N2O, an environmentally harmful greenhouse gas. Only approximately a half of the applied nitrogen is utilized by crops and the rest is either vaporized, leached, or lost as NO, N2O and N2 via soil microbial activity. Thus, improving the nitrogen use efficiency of cropping systems has become a global concern. Factors such as types and rates of fertilizer application, soil texture, moisture level, pH, and microbial activity/diversity play important roles in N2O production. Here, we report the results of N2O production from a set of chamber experiments on an acidic sandy-loam agricultural soil under varying levels of an inorganic N-fertilizer, urea. Stable isotope technique was employed to determine the effect of increasing N-fertilizer levels on N2O emissions and identify the microbial processes involved in fertilizer N-transformation that give rise to N2O. We monitored the isotopic changes in both substrate (ammonium and nitrate) and the product N2O during the entire course of the incubation experiments. Peak N2O emissions of 122 ± 98 μg N2O-N m-2 h-1, 338 ± 49 μg N2O-N m-2 h-1 and 739 ± 296 μg N2O-N m-2 h-1 were observed for urea application rate of 40, 80, and 120 μg N g-1. The duration of emissions also increased with urea levels. The concentration and isotopic compositions of the substrates and product showed time-bound variation. Combining the observations of isotopic effects in δ15N, δ18O, and 15N site preference, we inferred co-occurrence of several microbial N2O production pathways with nitrification and/or fungal denitrification as the dominant processes responsible for N2O emissions. Besides this, dominant signatures of bacterial denitrification were observed in a second N2O emission pulse in intermediate urea-N levels. Signature of N2O consumption by reduction could be traced during declining emissions in treatment with high urea level.
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Affiliation(s)
- Ritika Kaushal
- Institute of Earth Sciences, Academia Sinica, Taipei, Taiwan
| | - Yu-Hsin Hsueh
- Institute of Earth Sciences, Academia Sinica, Taipei, Taiwan; Taiwan International Graduate Program-Earth Systems Science, Academia Sinica, Taipei, Taiwan
| | - Chi-Ling Chen
- Agricultural Chemistry Division, Taiwan Agricultural Research Institute, Taichung, Taiwan
| | - Yi-Ping Lan
- Institute of Earth Sciences, Academia Sinica, Taipei, Taiwan
| | - Ping-Yu Wu
- Agricultural Chemistry Division, Taiwan Agricultural Research Institute, Taichung, Taiwan
| | - Yi-Chun Chen
- Agricultural Chemistry Division, Taiwan Agricultural Research Institute, Taichung, Taiwan
| | - Mao-Chang Liang
- Institute of Earth Sciences, Academia Sinica, Taipei, Taiwan.
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14
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Fang F, Li Y, Yuan D, Zheng Q, Ding J, Xu C, Lin W, Li Y. Distinguishing N 2O and N 2 ratio and their microbial source in soil fertilized for vegetable production using a stable isotope method. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 801:149694. [PMID: 34428661 DOI: 10.1016/j.scitotenv.2021.149694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 08/10/2021] [Accepted: 08/11/2021] [Indexed: 06/13/2023]
Abstract
Vegetable production systems with excessive nitrogen fertilizer result in severe N2O emission. It is pivotal to identify the source of N2O for reducing N2O emission, but estimating microbial pathways of N2O production is very difficult due to the existence of N2O reduction. A promising tool can address this problem by using δ18O and δ15NSP of N2O to construct a dual isotopocule plot. For ascertaining the microbial pathways of N2O production and consumption in soil fertilized for vegetable production, four treatments were set up: urea (U), half urea and half organic fertilizer (UO), organic fertilizer (O) and no fertilizer (NF), and the experiment was carried out continuously for two years. The δ18O vs. δ15NSP plot method indicated that the nitrification/fungal denitrification was a dominant in N2O emission, and the U treatment was the highest, followed by OU, O and NF in the both years. Among the different treatments, furthermore, the N2O flux had the same trend, whereas the extent of N2O reduction showed an opposite trend. Overall, inorganic fertilizer enhances nitrification/fungal denitrification and hinders reduction of N2O to N2, resulting in a larger amount of N2O emission. However, organic fertilizer increases the contribution of denitrification and greatly improves the extent of N2O reduction, which helps to reduce N2O emission. Therefore, organic fertilizer is crucial to reducing N2O emission by enhancing N2O reduction and should be properly applied in production practice.
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Affiliation(s)
- Fuli Fang
- Key Laboratory of Dryland Agriculture, Ministry of Agriculture and Rural Affairs of the People's Republic of China, Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Yujia Li
- Institute of Urban Agriculture, Chinese Academy of Agricultural Sciences, Chengdu 610213, China
| | - Dapeng Yuan
- Agriculture and Animal Husbandry Bureau, Songshan District, Chifeng 024000, China
| | - Qian Zheng
- Key Laboratory of Dryland Agriculture, Ministry of Agriculture and Rural Affairs of the People's Republic of China, Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Junjun Ding
- Key Laboratory of Dryland Agriculture, Ministry of Agriculture and Rural Affairs of the People's Republic of China, Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Chunying Xu
- Key Laboratory of Dryland Agriculture, Ministry of Agriculture and Rural Affairs of the People's Republic of China, Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Wei Lin
- Institute of Urban Agriculture, Chinese Academy of Agricultural Sciences, Chengdu 610213, China; Environmental Stable Isotope Lab., Chinese Academy of Agricultural Sciences, Beijing 100081, China.
| | - Yuzhong Li
- Key Laboratory of Dryland Agriculture, Ministry of Agriculture and Rural Affairs of the People's Republic of China, Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing 100081, China; Environmental Stable Isotope Lab., Chinese Academy of Agricultural Sciences, Beijing 100081, China.
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15
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Lewicka-Szczebak D, Jansen-Willems A, Müller C, Dyckmans J, Well R. Nitrite isotope characteristics and associated soil N transformations. Sci Rep 2021; 11:5008. [PMID: 33658538 PMCID: PMC7930258 DOI: 10.1038/s41598-021-83786-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Accepted: 02/05/2021] [Indexed: 12/02/2022] Open
Abstract
Nitrite (NO2−) is a crucial compound in the N soil cycle. As an intermediate of nearly all N transformations, its isotopic signature may provide precious information on the active pathways and processes. NO2− analyses have already been applied in 15N tracing studies, increasing their interpretation perspectives. Natural abundance NO2− isotope studies in soils were so far not applied and this study aims at testing if such analyses are useful in tracing the soil N cycle. We conducted laboratory soil incubations with parallel natural abundance and 15N treatments, accompanied by isotopic analyses of soil N compounds (NO3−, NO2−, NH4+). The double 15N tracing method was used as a reference method for estimations of N transformation processes based on natural abundance nitrite dynamics. We obtained a very good agreement between the results from nitrite isotope model proposed here and the 15N tracing approach. Natural abundance nitrite isotope studies are a promising tool to our understanding of soil N cycling.
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Affiliation(s)
- Dominika Lewicka-Szczebak
- Centre for Stable Isotope Research and Analysis, University of Göttingen, Göttingen, Germany. .,Laboratory of Isotope Geology and Geoecology, Institute of Geological Sciences, University of Wrocław, Wrocław, Poland.
| | | | - Christoph Müller
- Institute of Plant Ecology, Justus Liebig University, Giessen, Germany.,School of Biology and Environmental Science and Earth Institute, University College Dublin, Belfield, Dublin, Ireland
| | - Jens Dyckmans
- Centre for Stable Isotope Research and Analysis, University of Göttingen, Göttingen, Germany
| | - Reinhard Well
- Thünen-Institut of Climate-Smart Agriculture, Braunschweig, Germany
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16
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Aldossari N, Ishii S. Isolation of cold-adapted nitrate-reducing fungi that have potential to increase nitrate removal in woodchip bioreactors. J Appl Microbiol 2020; 131:197-207. [PMID: 33222401 DOI: 10.1111/jam.14939] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 11/12/2020] [Accepted: 11/17/2020] [Indexed: 11/27/2022]
Abstract
AIMS The aim of this study was to obtain cold-adapted denitrifying fungi that could be used for bioaugmentation in woodchip bioreactors to remove nitrate from agricultural subsurface drainage water. METHODS AND RESULTS We isolated a total of 91 nitrate-reducing fungal strains belonging to Ascomycota and Mucoromycota from agricultural soil and a woodchip bioreactor under relatively cold conditions (5 and 15°C). When these strains were incubated with 15 N-labelled nitrate, 29 N2 was frequently produced, suggesting the occurrence of co-denitrification (microbially mediated nitrosation). Two strains also produced 30 N2 , indicating their ability to reduce N2 O. Of the 91 nitrate-reducing fungal strains, fungal nitrite reductase gene (nirK) and cytochrome P450 nitric oxide reductase gene (p450nor) were detected by PCR in 34 (37%) and 11 (12%) strains, respectively. Eight strains possessed both nirK and p450nor, further verifying their denitrification capability. In addition, most strains degraded cellulose under denitrification condition. CONCLUSIONS Diverse nitrate-reducing fungi were isolated from soil and a woodchip bioreactor. These fungi reduced nitrate to gaseous N forms at relatively low temperatures. These cold-adapted, cellulose-degrading and nitrate-reducing fungi could support themselves and other denitrifiers in woodchip bioreactors. SIGNIFICANCE AND IMPACT OF THE STUDY The cold-adapted, cellulose-degrading and nitrate-reducing fungi isolated in this study could be useful to enhance nitrate removal in woodchip bioreactors under low-temperature conditions.
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Affiliation(s)
- N Aldossari
- Department of Soil, Water, and Climate, University of Minnesota, Saint Paul, MN, USA
| | - S Ishii
- Department of Soil, Water, and Climate, University of Minnesota, Saint Paul, MN, USA.,BioTechnology Institute, University of Minnesota, Saint Paul, MN, USA
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17
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Lourenço KS, Suleiman AKA, Pijl A, Cantarella H, Kuramae EE. Dynamics and resilience of soil mycobiome under multiple organic and inorganic pulse disturbances. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 733:139173. [PMID: 32454291 DOI: 10.1016/j.scitotenv.2020.139173] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Revised: 04/30/2020] [Accepted: 04/30/2020] [Indexed: 06/11/2023]
Abstract
Disturbances in soil can cause short-term soil changes, consequently changes in microbial community what may result in long-lasting ecological effects. Here, we evaluate how multiple pulse disturbances effect the dynamics and resilience of fungal community, and the co-occurrence of fungal and bacterial communities in a 389 days field experiment. We used soil under sugarcane cultivation as soil ecosystem model, and organic residue (vinasse - by-product of sugarcane ethanol production) combined or not with inorganic (organic residue applied 30 days before or together with mineral N fertilizer) amendments as disturbances. Application of organic residue alone as a single disturbance or 30 days prior to a second disturbance with mineral N resulted in similar changes in the fungal community. The simultaneous application of organic and mineral N as a single pulse disturbance had the greatest impact on the fungal community. Organic amendment increased the abundance of saprotrophs, fungal species capable of denitrification, and fungi described to have copiotrophic and oligotrophic lifestyles. Furthermore, the changes in the fungal community were not correlated with the changes in the bacterial community. The fungal community was neither resistant nor resilient to organic and inorganic disturbances over the one-year sampling period. Our findings provide insights on the immediate and delayed responses of the fungal community over one year to disturbance by organic and inorganic amendments.
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Affiliation(s)
- 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
| | - Afnan Khalil Ahmad Suleiman
- Microbial Ecology Department, Netherlands Institute of Ecology (NIOO), Droevendaalsesteeg 10, 6708, PB, Wageningen, the Netherlands; KWR Watercycle Research Institute, Groningenhaven 7, 3433, PE, Nieuwegein, The Netherlands
| | - Agata Pijl
- Microbial Ecology Department, Netherlands Institute of Ecology (NIOO), Droevendaalsesteeg 10, 6708, PB, Wageningen, the Netherlands
| | - 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; Ecology and Biodiversity, Institute of Environmental Biology, Utrecht University, Utrecht, The Netherlands.
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18
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Kong X, Ying S, Yang L, Xin Y, Cai Z, Zhu S, Liu D. Microbial and isotopomer analysis of N 2O generation pathways in ammonia removal biofilters. CHEMOSPHERE 2020; 251:126357. [PMID: 32146187 DOI: 10.1016/j.chemosphere.2020.126357] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Revised: 01/18/2020] [Accepted: 02/25/2020] [Indexed: 06/10/2023]
Abstract
Ammonia removal biofilters can be a potential source of nitrous oxide (N2O) production as a result of microbial nitrification and denitrification. In this study, these two N2O generation pathways was quantified using isotopic site preference values (SP, 33‰ for nitrification and 0‰ for denitrification) in a 204-d operation. Tests with two moisture conditions (45% and 55%) and three inlet NH3 concentrations (35, 18 and 0 ppmv) were performed. A 55+% NH3 removal efficiency was achieved in biofilters with 35 and 18 ppmv ammonia supply, but no significant difference (p > 0.05) was found between the moisture treatments. Results showed that biofilters were clearly net sources of N2O, and biofilters with higher moisture content generated significantly (p < 0.05) higher N2O concentration. The N2O generation did not stop even after the biofilters were terminated. The percentage of inlet NH3-N converted into N2O-N were 5.2%, 8.5% for biofilters with 45% moisture content, and 14.8%, 10.8% for those with 55% moisture content. Gene abundance of amoA and nosZ in packing materials (taken on days 64, 107, 140, 180 and 204) increased due to NH3 input reaching the highest on day 140 and then decreased in response to reduced NH3 supply on day 180 and 204. The changes of SP values suggested a shift between nitrification and denitrification with regard to N2O generation. Overall, the nitrification was the dominant pathway for N2O generation, but uncertainty exits as well. This study confirmed that NH3-loaded biofilters were net sources of N2O, and use of SP-N2O may be helpful in better understanding the processes responsible for such emissions.
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Affiliation(s)
- Xianwang Kong
- College of Biosystems Engineering and Food Science, Zhejiang University, China
| | - Shihao Ying
- College of Biosystems Engineering and Food Science, Zhejiang University, China
| | - Liangcheng Yang
- Department of Health Sciences Environmental Health Program, Illinois State University, USA.
| | - Yicong Xin
- College of Biosystems Engineering and Food Science, Zhejiang University, China
| | - Zhen Cai
- College of Biosystems Engineering and Food Science, Zhejiang University, China
| | - Songming Zhu
- College of Biosystems Engineering and Food Science, Zhejiang University, China
| | - Dezhao Liu
- College of Biosystems Engineering and Food Science, Zhejiang University, China.
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19
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Wu D, Well R, Cárdenas LM, Fuß R, Lewicka-Szczebak D, Köster JR, Brüggemann N, Bol R. Quantifying N 2O reduction to N 2 during denitrification in soils via isotopic mapping approach: Model evaluation and uncertainty analysis. ENVIRONMENTAL RESEARCH 2019; 179:108806. [PMID: 31627026 DOI: 10.1016/j.envres.2019.108806] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Revised: 10/05/2019] [Accepted: 10/06/2019] [Indexed: 06/10/2023]
Abstract
The last step of denitrification, i.e. the reduction of N2O to N2, has been intensively studied in the laboratory to understand the denitrification process, predict nitrogen fertiliser losses, and to establish mitigation strategies for N2O. However, assessing N2 production via denitrification at large spatial scales is still not possible due to lack of reliable quantitative approaches. Here, we present a novel numerical "mapping approach" model using the δ15Nsp/δ18O slope that has been proposed to potentially be used to indirectly quantify N2O reduction to N2 at field or larger spatial scales. We evaluate the model using data obtained from seven independent soil incubation studies conducted under a He-O2 atmosphere. Furthermore, we analyse the contribution of different parameters to the uncertainty of the model. The model performance strongly differed between studies and incubation conditions. Re-evaluation of the previous data set demonstrated that using soils-specific instead of default endmember values could largely improve model performance. Since the uncertainty of modelled N2O reduction was relatively high, further improvements to estimate model parameters to obtain more precise estimations remain an on-going matter, e.g. by determination of soil-specific isotope fractionation factors and isotopocule endmember values of N2O production processes using controlled laboratory incubations. The applicability of the mapping approach model is promising with an increasing availability of real-time and field based analysis of N2O isotope signatures.
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Affiliation(s)
- Di Wu
- Beijing Key Laboratory of Biodiversity and Organic Farming, College of Resources and Environmental Sciences, China Agricultural University, Beijing, China; Institute of Bio- and Geosciences, Agrosphere (IBG-3), Forschungszentrum Jülich GmbH, 52425, Jülich, Germany.
| | - Reinhard Well
- Thünen Institute of Climate-Smart Agriculture, Bundesallee 65, 38116, Braunschweig, Germany
| | | | - Roland Fuß
- Thünen Institute of Climate-Smart Agriculture, Bundesallee 65, 38116, Braunschweig, Germany
| | | | - Jan Reent Köster
- Thünen Institute of Climate-Smart Agriculture, Bundesallee 65, 38116, Braunschweig, Germany
| | - Nicolas Brüggemann
- Institute of Bio- and Geosciences, Agrosphere (IBG-3), Forschungszentrum Jülich GmbH, 52425, Jülich, Germany
| | - Roland Bol
- Institute of Bio- and Geosciences, Agrosphere (IBG-3), Forschungszentrum Jülich GmbH, 52425, Jülich, Germany
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Lenhart K, Behrendt T, Greiner S, Steinkamp J, Well R, Giesemann A, Keppler F. Nitrous oxide effluxes from plants as a potentially important source to the atmosphere. THE NEW PHYTOLOGIST 2019; 221:1398-1408. [PMID: 30303249 DOI: 10.1111/nph.15455] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Accepted: 08/19/2018] [Indexed: 05/12/2023]
Abstract
The global budget for nitrous oxide (N2 O), an important greenhouse gas and probably dominant ozone-depleting substance emitted in the 21st century, is far from being fully understood. Cycling of N2 O in terrestrial ecosystems has traditionally exclusively focused on gas exchange between the soil surface (nitrification-denitrification processes) and the atmosphere. Terrestrial vegetation has not been considered in the global budget so far, even though plants are known to release N2 O. Here, we report the N2 O emission rates of 32 plant species from 22 different families measured under controlled laboratory conditions. Furthermore, the first isotopocule values (δ15 N, δ18 O and δ15 Nsp ) of N2 O emitted from plants were determined. A robust relationship established between N2 O emission and CO2 respiration rates, which did not alter significantly over a broad range of changing environmental conditions, was used to quantify plant-derived emissions on an ecosystem scale. Stable isotope measurements (δ15 N, δ18 O and δ15 Nsp ) of N2 O emitted by plants clearly show that the dual isotopocule fingerprint of plant-derived N2 O differs from that of currently known microbial or chemical processes. Our work suggests that vegetation is a natural source of N2 O in the environment with a large fraction released by a hitherto unrecognized process.
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Affiliation(s)
- Katharina Lenhart
- Bingen University of Applied Sciences, Berlinstr. 109, Bingen, 55411, Germany
- Center for Organismal Studies, Im Neuenheimer Feld 360, Heidelberg, 69120, Germany
- Institute of Earth Sciences, Heidelberg University, Im Neuenheimer Feld 234-236, Heidelberg, D-69120, Germany
| | - Thomas Behrendt
- Max-Planck-Institute for Biogeochemistry, Hans Knöll Str. 10, Jena, 07745, Germany
| | - Steffen Greiner
- Center for Organismal Studies, Im Neuenheimer Feld 360, Heidelberg, 69120, Germany
| | - Jörg Steinkamp
- Biodiversity and Climate Research Centre, Senckenberg Gesellschaft für Naturforschung, Senckenberganlage 25, Frankfurt am Main, 60325, Germany
- Johannes Gutenberg-Universität, Anselm-Franz-von-Bentzel-Weg 12, D-55128 Mainz, Germany
| | - Reinhard Well
- Thünen-Institute of Climate-Smart Agriculture, Bundesallee 50, Braunschweig, D-38116, Germany
| | - Anette Giesemann
- Thünen-Institute of Climate-Smart Agriculture, Bundesallee 50, Braunschweig, D-38116, Germany
| | - Frank Keppler
- Institute of Earth Sciences, Heidelberg University, Im Neuenheimer Feld 234-236, Heidelberg, D-69120, Germany
- Heidelberg Center for the Environment (HCE), Heidelberg University, Heidelberg, D-69120, Germany
- Max-Planck-Institute for Chemistry, Hahn-Meitner-Weg 1, Mainz, D-55128, Germany
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21
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Hyodo A, Malghani S, Zhou Y, Mushinski RM, Toyoda S, Yoshida N, Boutton TW, West JB. Biochar amendment suppresses N 2 O emissions but has no impact on 15 N site preference in an anaerobic soil. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2019; 33:165-175. [PMID: 30304571 DOI: 10.1002/rcm.8305] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Revised: 10/03/2018] [Accepted: 10/04/2018] [Indexed: 06/08/2023]
Abstract
RATIONALE Biochar amendments often decrease N2 O gas production from soil, but the mechanisms and magnitudes are still not well characterized since N2 O can be produced via several different microbial pathways. We evaluated the influence of biochar amendment on N2 O emissions and N2 O isotopic composition, including 15 N site preference (SP) under anaerobic conditions. METHODS An agricultural soil was incubated with differing levels of biochar. Incubations were conducted under anaerobic conditions for 10 days with and without acetylene, which inhibits N2 O reduction to N2 . The N2 O concentrations were measured every 2 days, the SPs were determined after 5 days of incubation, and the inorganic nitrogen concentrations were measured after the incubation. RESULTS The SP values with acetylene were consistent with N2 O production by bacterial denitrification and those without acetylene were consistent with bacterial denitrification that included N2 O reduction to N2 . There was no effect of biochar on N2 O production in the presence of acetylene between day 3 and day 10. However, in the absence of acetylene, soils incubated with 4% biochar produced less N2 O than soils with no biochar addition. Different amounts of biochar amendment did not change the SP values. CONCLUSIONS Our study used N2 O emission rates and SP values to understand biochar amendment mechanisms and demonstrated that biochar amendment reduces N2 O emissions by stimulating the last step of denitrification. It also suggested a possible shift in N2 O-reducing microbial taxa in 4% biochar samples.
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Affiliation(s)
- Ayumi Hyodo
- Department of Ecosystem Science and Management, Texas A&M University, College Station, TX, 77843, USA
| | - Saadatullah Malghani
- Department of Ecosystem Science and Management, Texas A&M University, College Station, TX, 77843, USA
- School of Civil and Environmental Engineering, Yonsei University, Yonsei-ro 50 Saedaemun-gu, Seoul, 03722, South Korea
| | - Yong Zhou
- Department of Ecosystem Science and Management, Texas A&M University, College Station, TX, 77843, USA
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT, 06511, USA
| | - Ryan M Mushinski
- Department of Ecosystem Science and Management, Texas A&M University, College Station, TX, 77843, USA
- School of Public and Environmental Affairs, Indiana University, Bloomington, IN, 47405, USA
| | - Sakae Toyoda
- Department of Chemical Science and Engineering, School of Materials and Chemical Technology, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama, 226-8503, Japan
| | - Naohiro Yoshida
- Department of Chemical Science and Engineering, School of Materials and Chemical Technology, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama, 226-8503, Japan
- Earth-Life Science Institute, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo, 152-8550, Japan
| | - Thomas W Boutton
- Department of Ecosystem Science and Management, Texas A&M University, College Station, TX, 77843, USA
| | - Jason B West
- Department of Ecosystem Science and Management, Texas A&M University, College Station, TX, 77843, USA
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22
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Higgins SA, Schadt CW, Matheny PB, Löffler FE. Phylogenomics Reveal the Dynamic Evolution of Fungal Nitric Oxide Reductases and Their Relationship to Secondary Metabolism. Genome Biol Evol 2018; 10:2474-2489. [PMID: 30165640 PMCID: PMC6161760 DOI: 10.1093/gbe/evy187] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/23/2018] [Indexed: 12/16/2022] Open
Abstract
Fungi expressing P450nor, an unconventional nitric oxide (NO) reducing cytochrome P450, are considered significant contributors to environmental nitrous oxide (N2O) emissions. Despite extensive efforts, fungal contributions to N2O emissions remain uncertain. For example, the majority of N2O emitted from antibiotic-amended soil microcosms is attributed to fungal activity, yet axenic fungal cultures do not couple N-oxyanion respiration to growth and these fungi produce only minor quantities of N2O. To assist in reconciling these conflicting observations and produce a benchmark genomic analysis of fungal denitrifiers, genes underlying denitrification were examined in >700 fungal genomes. Of 167 p450nor—containing genomes identified, 0, 30, and 48 also harbored the denitrification genes narG, napA, or nirK, respectively. Compared with napA and nirK, p450nor was twice as abundant and exhibited 2–5-fold more gene duplications, losses, and transfers, indicating a disconnect between p450nor presence and denitrification potential. Furthermore, cooccurrence of p450nor with genes encoding NO-detoxifying flavohemoglobins (Spearman r = 0.87, p = 1.6e−10) confounds hypotheses regarding P450nor’s primary role in NO detoxification. Instead, ancestral state reconstruction united P450nor with actinobacterial cytochrome P450s (CYP105) involved in secondary metabolism (SM) and 19 (11%) p450nor-containing genomic regions were predicted to be SM clusters. Another 40 (24%) genomes harbored genes nearby p450nor predicted to encode hallmark SM functions, providing additional contextual evidence linking p450nor to SM. These findings underscore the potential physiological implications of widespread p450nor gene transfer, support the undiscovered affiliation of p450nor with fungal SM, and challenge the hypothesis of p450nor’s primary role in denitrification.
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Affiliation(s)
- Steven A Higgins
- Department of Microbiology, University of Tennessee, Knoxville.,Biosciences Division, Oak Ridge National Laboratory, Oak Ridge
| | - Christopher W Schadt
- Department of Microbiology, University of Tennessee, Knoxville.,Biosciences Division, Oak Ridge National Laboratory, Oak Ridge.,University of Tennessee and Oak Ridge National Laboratory (UT-ORNL), Joint Institute for Biological Sciences (JIBS), Oak Ridge
| | - Patrick B Matheny
- Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville
| | - Frank E Löffler
- Department of Microbiology, University of Tennessee, Knoxville.,Biosciences Division, Oak Ridge National Laboratory, Oak Ridge.,University of Tennessee and Oak Ridge National Laboratory (UT-ORNL), Joint Institute for Biological Sciences (JIBS), Oak Ridge.,Department of Civil and Environmental Engineering, University of Tennessee, Knoxville.,Department of Biosystems Engineering and Soil Science, University of Tennessee, Knoxville.,Center for Environmental Biotechnology, University of Tennessee, Knoxville
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23
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Buchen C, Lewicka-Szczebak D, Flessa H, Well R. Estimating N 2 O processes during grassland renewal and grassland conversion to maize cropping using N 2 O isotopocules. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2018; 32:1053-1067. [PMID: 29603803 DOI: 10.1002/rcm.8132] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Revised: 03/21/2018] [Accepted: 03/21/2018] [Indexed: 05/27/2023]
Abstract
RATIONALE Enhanced nitrous oxide (N2 O) emissions can occur following grassland break-up for renewal or conversion to maize cropping, but knowledge about N2 O production pathways and N2 O reduction to N2 is very limited. A promising tool to address this is the combination of mass spectrometric analysis of N2 O isotopocules and an enhanced approach for data interpretation. METHODS The isotopocule mapping approach was applied to field data using a δ15 NspN2O and δ18 ON2O map to simultaneously determine N2 O production pathways contribution and N2 O reduction for the first time. Based on the isotopic composition of N2 O produced and literature values for specific N2 O pathways, it was possible to distinguish: (i) heterotrophic bacterial denitrification and/or nitrifier denitrification and (ii) nitrification and/or fungal denitrification and the contribution of N2 O reduction. RESULTS The isotopic composition of soil-emitted N2 O largely resembled the known end-member values for bacterial denitrification. The isotopocule mapping approach indicated different effects of N2 O reduction on the isotopic composition of soil-emitted N2 O for the two soils under study. Differing N2 O production pathways in different seasons were not observed, but management events and soil conditions had a significant impact on pathway contribution and N2 O reduction. N2 O reduction data were compared with a parallel 15 N-labelling experiment. CONCLUSIONS The field application of the isotopocule mapping approach opens up new prospects for studying N2 O production and consumption of N2 O in soil simultaneously based on mass spectrometric analysis of natural abundance N2 O. However, further studies are needed in order to properly validate the isotopocule mapping approach.
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Affiliation(s)
- Caroline Buchen
- Thünen-Institute of Climate-Smart Agriculture, Bundesallee 50, 38116, Braunschweig, Germany
- Leibniz Centre for Agricultural Landscape Research (ZALF), Eberswalder Str. 84, 15374, Muencheberg, Germany
| | | | - Heinz Flessa
- Thünen-Institute of Climate-Smart Agriculture, Bundesallee 50, 38116, Braunschweig, Germany
| | - Reinhard Well
- Thünen-Institute of Climate-Smart Agriculture, Bundesallee 50, 38116, Braunschweig, Germany
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Maeda K, Toyoda S, Philippot L, Hattori S, Nakajima K, Ito Y, Yoshida N. Relative Contribution of nirK- and nirS- Bacterial Denitrifiers as Well as Fungal Denitrifiers to Nitrous Oxide Production from Dairy Manure Compost. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:14083-14091. [PMID: 29182319 DOI: 10.1021/acs.est.7b04017] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The relative contribution of fungi, bacteria, and nirS and nirK denirifiers to nitrous oxide (N2O) emission with unknown isotopic signature from dairy manure compost was examined by selective inhibition techniques. Chloramphenicol (CHP), cycloheximide (CYH), and diethyl dithiocarbamate (DDTC) were used to suppress the activity of bacteria, fungi, and nirK-possessing denitrifiers, respectively. Produced N2O were surveyed to isotopocule analysis, and its 15N site preference (SP) and δ18O values were compared. Bacteria, fungi, nirS, and nirK gene abundances were compared by qPCR. The results showed that N2O production was strongly inhibited by CHP addition in surface pile samples (82.2%) as well as in nitrite-amended core samples (98.4%), while CYH addition did not inhibit the N2O production. N2O with unknown isotopic signature (SP = 15.3-16.2‰), accompanied by δ18O (19.0-26.8‰) values which were close to bacterial denitrification, was also suppressed by CHP and DDTC addition (95.3%) indicating that nirK denitrifiers were responsible for this N2O production despite being less abundant than nirS denitrifiers. Altogether, our results suggest that bacteria are important for N2O production with different SP values both from compost surface and pile core. However, further work is required to decipher whether N2O with unknown isotopic signature is mostly due to nirK denitrifiers that are taxonomically different from the SP-characterized strains and therefore have different SP values rather than also being interwoven with the contribution of the NO-detoxifying pathway and/or of co-denitrification.
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Affiliation(s)
- Koki Maeda
- NARO, Hokkaido Agricultural Research Center, Dairy Research Division , 1 Hitsujigaoka, Sapporo 062-8555, Japan
| | - Sakae Toyoda
- Department of Chemical Science and Engineering, School of Materials and Chemical Technology, Tokyo Instititute of Technology , 4259 Nagatsuta, Midori-ku, Yokohama 226-8502, Japan
| | - Laurent Philippot
- INRA, UMR 1229, Soil and Environmental Microbiology , 17 rue Sully BP 86510, Dijon 21065 Cedex, France
| | - Shohei Hattori
- Department of Chemical Science and Engineering, School of Materials and Chemical Technology, Tokyo Instititute of Technology , 4259 Nagatsuta, Midori-ku, Yokohama 226-8502, Japan
| | - Keiichi Nakajima
- NARO, Hokkaido Agricultural Research Center, Dairy Research Division , 1 Hitsujigaoka, Sapporo 062-8555, Japan
| | - Yumi Ito
- NARO, Hokkaido Agricultural Research Center, Dairy Research Division , 1 Hitsujigaoka, Sapporo 062-8555, Japan
| | - Naohiro Yoshida
- Department of Chemical Science and Engineering, School of Materials and Chemical Technology, Tokyo Instititute of Technology , 4259 Nagatsuta, Midori-ku, Yokohama 226-8502, Japan
- Earth-Life Science Institute, Tokyo Institute of Technology , 2-12-1 Ookayama, Meguro-ku Tokyo 152-8550, Japan
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25
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Rohe L, Well R, Lewicka-Szczebak D. Use of oxygen isotopes to differentiate between nitrous oxide produced by fungi or bacteria during denitrification. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2017; 31:1297-1312. [PMID: 28556299 DOI: 10.1002/rcm.7909] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Revised: 05/23/2017] [Accepted: 05/23/2017] [Indexed: 06/07/2023]
Abstract
RATIONALE Fungal denitrifiers can contribute substantially to N2 O emissions from arable soil and show a distinct site preference for N2 O (SP(N2 O)). This study sought to identify another process-specific isotopic tool to improve precise identification of N2 O of fungal origin by mass spectrometric analysis of the N2 O produced. METHODS Three pure bacterial and three fungal species were incubated under denitrifying conditions in treatments with natural abundance and stable isotope labelling to analyse the N2 O produced. Combining different applications of isotope ratio mass spectrometry enabled us to estimate the oxygen (O) exchange accelerated by denitrifying enzymes and the ongoing microbial pathway in parallel. This experimental set-up allowed the determination of δ18 O(N2 O) values and isotopic fractionation of O, as well as SP(N2 O) values, as a perspective to differentiate between microbial denitrifiers. RESULTS Oxygen exchange during N2 O production was lower for bacteria than for fungi, differed between species, and depended also on incubation time. Apparent O isotopic fractionation during denitrification was in a similar range for bacteria and fungi, but application of the fractionation model indicated that different enzymes in bacteria and fungi were responsible for O exchange. This difference was associated with different isotopic fractionation for bacteria and fungi. CONCLUSIONS δ18 O(N2 O) values depend on isotopic fractionation and isotopic fractionation may differ between processes and organism groups. By comparing SP(N2 O) values, O exchange and the isotopic signature of precursors, we propose here a novel tool for differentiating between different sources of N2 O.
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Affiliation(s)
- Lena Rohe
- Thünen Institute of Climate-Smart Agriculture, Braunschweig, Germany
| | - Reinhard Well
- Thünen Institute of Climate-Smart Agriculture, Braunschweig, Germany
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26
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Evidence for fungal and chemodenitrification based N 2O flux from nitrogen impacted coastal sediments. Nat Commun 2017; 8:15595. [PMID: 28580932 PMCID: PMC5465357 DOI: 10.1038/ncomms15595] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Accepted: 03/06/2017] [Indexed: 12/17/2022] Open
Abstract
Although increasing atmospheric nitrous oxide (N2O) has been linked to nitrogen loading, predicting emissions remains difficult, in part due to challenges in disentangling diverse N2O production pathways. As coastal ecosystems are especially impacted by elevated nitrogen, we investigated controls on N2O production mechanisms in intertidal sediments using novel isotopic approaches and microsensors in flow-through incubations. Here we show that during incubations with elevated nitrate, increased N2O fluxes are not mediated by direct bacterial activity, but instead are largely catalysed by fungal denitrification and/or abiotic reactions (e.g., chemodenitrification). Results of these incubations shed new light on nitrogen cycling complexity and possible factors underlying variability of N2O fluxes, driven in part by fungal respiration and/or iron redox cycling. As both processes exhibit N2O yields typically far greater than direct bacterial production, these results emphasize their possibly substantial, yet widely overlooked, role in N2O fluxes, especially in redox-dynamic sediments of coastal ecosystems.
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Toyoda S, Yoshida N, Koba K. Isotopocule analysis of biologically produced nitrous oxide in various environments. MASS SPECTROMETRY REVIEWS 2017; 36:135-160. [PMID: 25869149 DOI: 10.1002/mas.21459] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Revised: 01/13/2015] [Accepted: 01/13/2015] [Indexed: 06/04/2023]
Abstract
Natural abundance ratios of isotopocules, molecules that have the same chemical constitution and configuration, but that only differ in isotope substitution, retain a record of a compound's origin and reactions. A method to measure isotopocule ratios of nitrous oxide (N2 O) has been established by using mass analysis of molecular ions and fragment ions. The method has been applied widely to environmental samples from the atmosphere, ocean, fresh water, soils, and laboratory-simulation experiments. Results show that isotopocule ratios, particularly the 15 N-site preference (difference between isotopocule ratios 14 N15 N16 O/14 N14 N16 O and 15 N14 N16 O/14 N14 N16 O), have a wide range that depends on their production and consumption processes. Observational and laboratory studies of N2 O related to biological processes are reviewed and discussed to elucidate complex material cycles of this trace gas, which causes global warming and stratospheric ozone depletion. © 2015 Wiley Periodicals, Inc. Mass Spec Rev 36:135-160, 2017.
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Affiliation(s)
- Sakae Toyoda
- Department of Environmental Science and Technology, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8502, Japan
| | - Naohiro Yoshida
- Department of Environmental Science and Technology, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8502, Japan
- Department of Environmental Chemistry and Engineering, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8502, Japan
- Earth-Life Science Institute, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan
| | - Keisuke Koba
- Institute of Agriculture, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu-City, Tokyo 183-8509, Japan
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Phillips RL, Song B, McMillan AMS, Grelet G, Weir BS, Palmada T, Tobias C. Chemical formation of hybrid di-nitrogen calls fungal codenitrification into question. Sci Rep 2016; 6:39077. [PMID: 27976694 PMCID: PMC5157039 DOI: 10.1038/srep39077] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Accepted: 11/17/2016] [Indexed: 11/09/2022] Open
Abstract
Removal of excess nitrogen (N) can best be achieved through denitrification processes that transform N in water and terrestrial ecosystems to di-nitrogen (N2) gas. The greenhouse gas nitrous oxide (N2O) is considered an intermediate or end-product in denitrification pathways. Both abiotic and biotic denitrification processes use a single N source to form N2O. However, N2 can be formed from two distinct N sources (known as hybrid N2) through biologically mediated processes of anammox and codenitrification. We questioned if hybrid N2 produced during fungal incubation at neutral pH could be attributed to abiotic nitrosation and if N2O was consumed during N2 formation. Experiments with gas chromatography indicated N2 was formed in the presence of live and dead fungi and in the absence of fungi, while N2O steadily increased. We used isotope pairing techniques and confirmed abiotic production of hybrid N2 under both anoxic and 20% O2 atmosphere conditions. Our findings question the assumptions that (1) N2O is an intermediate required for N2 formation, (2) production of N2 and N2O requires anaerobiosis, and (3) hybrid N2 is evidence of codenitrification and/or anammox. The N cycle framework should include abiotic production of N2.
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Affiliation(s)
| | - Bongkeun Song
- Dept. of Biological Sciences, Virginia Institute of Marine Science, Gloucester Point, Virginia, USA
| | | | - Gwen Grelet
- Landcare Research, Gerald Street, Lincoln, New Zealand
| | - Bevan S Weir
- Landcare Research, Gerald Street, Lincoln, New Zealand
| | | | - Craig Tobias
- Dept. of Marine Sciences, University of Connecticut, Groton, Connecticut, USA
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Schorpp Q, Riggers C, Lewicka-Szczebak D, Giesemann A, Well R, Schrader S. Influence of Lumbricus terrestris and Folsomia candida on N 2 O formation pathways in two different soils - with particular focus on N 2 emissions. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2016; 30:2301-2314. [PMID: 27510404 DOI: 10.1002/rcm.7716] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Revised: 08/05/2016] [Accepted: 08/09/2016] [Indexed: 06/06/2023]
Abstract
RATIONALE The gaseous N losses mediated by soil denitrifiers are generally inferred by measuring N2 O fluxes, but should include associated N2 emissions, which may be affected by abiotic soil characteristics and biotic interactions. Soil fauna, particularly anecic earthworms and euedaphic collembola, alter the activity of denitrifiers, creating hotspots for denitrification. These soil fauna are abundant in perennial agroecosystems intended to contribute to more sustainable production of bioenergy. METHODS Two microcosm experiments were designed to evaluate gaseous N emissions from a silty loam and a sandy soil, both provided with litter from the bioenergy crop Silphium perfoliatum (cup-plant) and inoculated with an anecic earthworm (Lumbricus terrestris), which was added alone or together with an euedaphic collembola (Folsomia candida). In experiment 1, litter-derived N flux was determined by adding 15 N-labelled litter, followed by mass spectrometric analysis of N2 and N2 O isotopologues. In experiment 2, the δ18 O values and 15 N site preference of N2 O were determined by isotope ratio mass spectrometry to reveal underlying N2 O formation pathways. RESULTS Lumbricus terrestris significantly increased litter-derived N2 emissions in the loamy soil, from 174.5 to 1019.3 μg N2 -N kg-1 soil, but not in the sandy soil (non-significant change from 944.7 to 1054.7 μg N2 -N kg-1 soil). Earthworm feeding on plant litter resulted in elevated N2 O emissions in both soils, derived mainly from turnover of the soil mineral N pool during denitrification. Folsomia candida did not affect N losses but showed a tendency to redirect N2 O formation pathways from fungal to bacterial denitrification. The N2 O/(N2 + N2 O) product ratio was predominantly affected by abiotic soil characteristics (loamy soil: 0.14, sandy soil: 0.26). CONCLUSIONS When feeding on S. perfoliatum litter, the anecic L. terrestris, but not the euedaphic F. candida, has the potential to cause substantial N losses. Biotic interactions between the species are not influential, but abiotic soil characteristics have an effect. The coarse-textured sandy soil had lower gaseous N losses attributable to anecic earthworms. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
- Quentin Schorpp
- Johann Heinrich von Thünen-Institute (TI) - Federal Institute for Rural Areas, Forestry and Fisheries, Institute of Biodiversity, Bundesallee 50, D-38116, Braunschweig, Germany.
| | - Catharina Riggers
- Johann Heinrich von Thünen-Institute (TI) - Federal Institute for Rural Areas, Forestry and Fisheries, Institute of Biodiversity, Bundesallee 50, D-38116, Braunschweig, Germany
| | - Dominika Lewicka-Szczebak
- Johann Heinrich von Thünen-Institute (TI) - Federal Institute for Rural Areas, Forestry and Fisheries, Institute of Climate-Smart Agriculture, Bundesallee 50, D-38116, Braunschweig, Germany
| | - Anette Giesemann
- Johann Heinrich von Thünen-Institute (TI) - Federal Institute for Rural Areas, Forestry and Fisheries, Institute of Climate-Smart Agriculture, Bundesallee 50, D-38116, Braunschweig, Germany
| | - Reinhard Well
- Johann Heinrich von Thünen-Institute (TI) - Federal Institute for Rural Areas, Forestry and Fisheries, Institute of Climate-Smart Agriculture, Bundesallee 50, D-38116, Braunschweig, Germany
| | - Stefan Schrader
- Johann Heinrich von Thünen-Institute (TI) - Federal Institute for Rural Areas, Forestry and Fisheries, Institute of Biodiversity, Bundesallee 50, D-38116, Braunschweig, Germany
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Mosier AC, Miller CS, Frischkorn KR, Ohm RA, Li Z, LaButti K, Lapidus A, Lipzen A, Chen C, Johnson J, Lindquist EA, Pan C, Hettich RL, Grigoriev IV, Singer SW, Banfield JF. Fungi Contribute Critical but Spatially Varying Roles in Nitrogen and Carbon Cycling in Acid Mine Drainage. Front Microbiol 2016; 7:238. [PMID: 26973616 PMCID: PMC4776211 DOI: 10.3389/fmicb.2016.00238] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Accepted: 02/15/2016] [Indexed: 11/22/2022] Open
Abstract
The ecosystem roles of fungi have been extensively studied by targeting one organism and/or biological process at a time, but the full metabolic potential of fungi has rarely been captured in an environmental context. We hypothesized that fungal genome sequences could be assembled directly from the environment using metagenomics and that transcriptomics and proteomics could simultaneously reveal metabolic differentiation across habitats. We reconstructed the near-complete 27 Mbp genome of a filamentous fungus, Acidomyces richmondensis, and evaluated transcript and protein expression in floating and streamer biofilms from an acid mine drainage (AMD) system. A. richmondensis transcripts involved in denitrification and in the degradation of complex carbon sources (including cellulose) were up-regulated in floating biofilms, whereas central carbon metabolism and stress-related transcripts were significantly up-regulated in streamer biofilms. These findings suggest that the biofilm niches are distinguished by distinct carbon and nitrogen resource utilization, oxygen availability, and environmental challenges. An isolated A. richmondensis strain from this environment was used to validate the metagenomics-derived genome and confirm nitrous oxide production at pH 1. Overall, our analyses defined mechanisms of fungal adaptation and identified a functional shift related to different roles in carbon and nitrogen turnover for the same species of fungi growing in closely located but distinct biofilm niches.
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Affiliation(s)
- Annika C. Mosier
- Department of Earth and Planetary Science, University of California, BerkeleyBerkeley, CA, USA
| | - Christopher S. Miller
- Department of Earth and Planetary Science, University of California, BerkeleyBerkeley, CA, USA
| | - Kyle R. Frischkorn
- Department of Earth and Planetary Science, University of California, BerkeleyBerkeley, CA, USA
| | - Robin A. Ohm
- US Department of Energy Joint Genome InstituteWalnut Creek, CA, USA
| | - Zhou Li
- Oak Ridge National LaboratoryOak Ridge, TN, USA
- Graduate School of Genome Science and Technology, University of Tennessee-Oak Ridge National LaboratoryKnoxville, TN, USA
| | - Kurt LaButti
- US Department of Energy Joint Genome InstituteWalnut Creek, CA, USA
| | - Alla Lapidus
- US Department of Energy Joint Genome InstituteWalnut Creek, CA, USA
| | - Anna Lipzen
- US Department of Energy Joint Genome InstituteWalnut Creek, CA, USA
| | - Cindy Chen
- US Department of Energy Joint Genome InstituteWalnut Creek, CA, USA
| | - Jenifer Johnson
- US Department of Energy Joint Genome InstituteWalnut Creek, CA, USA
| | | | - Chongle Pan
- Oak Ridge National LaboratoryOak Ridge, TN, USA
| | | | | | - Steven W. Singer
- Earth Sciences Division, Lawrence Berkeley National LaboratoryBerkeley, CA, USA
| | - Jillian F. Banfield
- Department of Earth and Planetary Science, University of California, BerkeleyBerkeley, CA, USA
- Department of Environmental Science, Policy, and Management, University of California, BerkeleyBerkeley, CA, USA
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31
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Phillips R, Grelet G, McMillan A, Song B, Weir B, Palmada T, Tobias C. Fungal denitrification: Bipolaris sorokiniana exclusively denitrifies inorganic nitrogen in the presence and absence of oxygen. FEMS Microbiol Lett 2016; 363:fnw007. [PMID: 26764425 DOI: 10.1093/femsle/fnw007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/08/2016] [Indexed: 11/12/2022] Open
Abstract
Fungi may play an important role in the production of the greenhouse gas nitrous oxide (N2O). Bipolaris sorokiniana is a ubiquitous saprobe found in soils worldwide, yet denitrification by this fungal strain has not previously been reported. We aimed to test if B. sorokiniana would produce N2O and CO2 in the presence of organic and inorganic forms of nitrogen (N) under microaerobic and anaerobic conditions. Nitrogen source (organic-N, inorganic-N, no-N control) significantly affected N2O and CO2 production both in the presence and absence of oxygen, which contrasts with bacterial denitrification. Inorganic N addition increased denitrification of N2O (from 0 to 0.3 μg N20-N h(-1) g(-1) biomass) and reduced respiration of CO2 (from 0.1 to 0.02 mg CO2 h(-1) g(-1) biomass). Isotope analyses indicated that nitrite, rather than ammonium or glutamine, was transformed to N2O. Results suggest the source of N may play a larger role in fungal N2O production than oxygen status.
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Affiliation(s)
- Rebecca Phillips
- Landcare Research, Gerald Street, Lincoln, Canterbury 7608, New Zealand
| | - Gwen Grelet
- Landcare Research, Gerald Street, Lincoln, Canterbury 7608, New Zealand
| | - Andrew McMillan
- Landcare Research, Gerald Street, Lincoln, Canterbury 7608, New Zealand
| | - Bongkeun Song
- Department of Biological Sciences, Virginia Institute of Marine Science, Gloucester Point, VA 23062, USA
| | - Bevan Weir
- Landcare Research, Gerald Street, Lincoln, Canterbury 7608, New Zealand
| | - Thilak Palmada
- Landcare Research, Gerald Street, Lincoln, Canterbury 7608, New Zealand
| | - Craig Tobias
- Department of Marine Sciences, University of Connecticut, Groton, CT 06269, USA
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Harris E, Joss A, Emmenegger L, Kipf M, Wolf B, Mohn J, Wunderlin P. Isotopic evidence for nitrous oxide production pathways in a partial nitritation-anammox reactor. WATER RESEARCH 2015; 83:258-270. [PMID: 26164660 DOI: 10.1016/j.watres.2015.06.040] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2014] [Revised: 03/25/2015] [Accepted: 06/25/2015] [Indexed: 06/04/2023]
Abstract
Nitrous oxide (N2O) production pathways in a single stage, continuously fed partial nitritation-anammox reactor were investigated using online isotopic analysis of offgas N2O with quantum cascade laser absorption spectroscopy (QCLAS). N2O emissions increased when reactor operating conditions were not optimal, for example, high dissolved oxygen concentration. SP measurements indicated that the increase in N2O was due to enhanced nitrifier denitrification, generally related to nitrite build-up in the reactor. The results of this study confirm that process control via online N2O monitoring is an ideal method to detect imbalances in reactor operation and regulate aeration, to ensure optimal reactor conditions and minimise N2O emissions. Under normal operating conditions, the N2O isotopic site preference (SP) was much higher than expected - up to 40‰ - which could not be explained within the current understanding of N2O production pathways. Various targeted experiments were conducted to investigate the characteristics of N2O formation in the reactor. The high SP measurements during both normal operating and experimental conditions could potentially be explained by a number of hypotheses: i) unexpectedly strong heterotrophic N2O reduction, ii) unknown inorganic or anammox-associated N2O production pathway, iii) previous underestimation of SP fractionation during N2O production from NH2OH, or strong variations in SP from this pathway depending on reactor conditions. The second hypothesis - an unknown or incompletely characterised production pathway - was most consistent with results, however the other possibilities cannot be discounted. Further experiments are needed to distinguish between these hypotheses and fully resolve N2O production pathways in PN-anammox systems.
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Affiliation(s)
- Eliza Harris
- Laboratory for Air Pollution and Environmental Technology, Empa, Überlandstrasse 129, 8600 Dübendorf, Switzerland.
| | - Adriano Joss
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Überlandstrasse 133, 8600 Dübendorf, Switzerland
| | - Lukas Emmenegger
- Laboratory for Air Pollution and Environmental Technology, Empa, Überlandstrasse 129, 8600 Dübendorf, Switzerland
| | - Marco Kipf
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Überlandstrasse 133, 8600 Dübendorf, Switzerland
| | - Benjamin Wolf
- Laboratory for Air Pollution and Environmental Technology, Empa, Überlandstrasse 129, 8600 Dübendorf, Switzerland; Institute of Meteorology and Climate Research (IMK-IFU), Karlsruhe Institute of Technology, Kreuzeckbahnstrasse 19, 82467 Garmisch-Partenkirchen, Germany
| | - Joachim Mohn
- Laboratory for Air Pollution and Environmental Technology, Empa, Überlandstrasse 129, 8600 Dübendorf, Switzerland
| | - Pascal Wunderlin
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Überlandstrasse 133, 8600 Dübendorf, Switzerland
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Lewicka-Szczebak D, Well R, Bol R, Gregory AS, Matthews GP, Misselbrook T, Whalley WR, Cardenas LM. Isotope fractionation factors controlling isotopocule signatures of soil-emitted N₂O produced by denitrification processes of various rates. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2015; 29:269-282. [PMID: 26411625 DOI: 10.1002/rcm.7102] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2014] [Revised: 11/14/2014] [Accepted: 11/17/2014] [Indexed: 06/05/2023]
Abstract
RATIONALE This study aimed (i) to determine the isotopic fractionation factors associated with N2O production and reduction during soil denitrification and (ii) to help specify the factors controlling the magnitude of the isotope effects. For the first time the isotope effects of denitrification were determined in an experiment under oxic atmosphere and using a novel approach where N2O production and reduction occurred simultaneously. METHODS Soil incubations were performed under a He/O2 atmosphere and the denitrification product ratio [N2O/(N2 + N2O)] was determined by direct measurement of N2 and N2O fluxes. N2O isotopocules were analyzed by mass spectrometry to determine δ(18)O, δ(15)N and (15)N site preference within the linear N2O molecule (SP). An isotopic model was applied for the simultaneous determination of net isotope effects (η) of both N2O production and reduction, taking into account emissions from two distinct soil pools. RESULTS A clear relationship was observed between (15)N and (18)O isotope effects during N2O production and denitrification rates. For N2O reduction, diverse isotope effects were observed for the two distinct soil pools characterized by different product ratios. For moderate product ratios (from 0.1 to 1.0) the range of isotope effects given by previous studies was confirmed and refined, whereas for very low product ratios (below 0.1) the net isotope effects were much smaller. CONCLUSIONS The fractionation factors associated with denitrification, determined under oxic incubation, are similar to the factors previously determined under anoxic conditions, hence potentially applicable for field studies. However, it was shown that the η(18)O/η(15)N ratios, previously accepted as typical for N2O reduction processes (i.e., higher than 2), are not valid for all conditions.
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Affiliation(s)
- Dominika Lewicka-Szczebak
- Thünen Institute of Climate-Smart Agriculture, Federal Research Institute for Rural Areas, Forestry and Fisheries, Bundesallee 50, D-38116, Braunschweig, Germany
- Institute of Geological Sciences, University of Wrocław, Cybulskiego 30, PL-50-205, Wroclaw, Poland
| | - Reinhard Well
- Thünen Institute of Climate-Smart Agriculture, Federal Research Institute for Rural Areas, Forestry and Fisheries, Bundesallee 50, D-38116, Braunschweig, Germany
| | - Roland Bol
- Forschungszentrum Jülich IBG-3, Wilhelm-Johnen-Straße, 52428, Jülich, Germany
| | | | - G Peter Matthews
- Faculty of Science & Environment, University of Plymouth, Plymouth, PL4 8AA, UK
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