1
|
Li H, Tang Y, Gao W, Pan W, Jiang C, Lee X, Cheng J. Response of soil N 2O production pathways to biochar amendment and its isotope discrimination methods. CHEMOSPHERE 2024; 350:141002. [PMID: 38145843 DOI: 10.1016/j.chemosphere.2023.141002] [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: 09/01/2023] [Revised: 11/30/2023] [Accepted: 12/19/2023] [Indexed: 12/27/2023]
Abstract
Reducing nitrous oxide (N2O) emission from farmland is crucial for alleviating global warming since agriculture is an important contributor of atmospheric N2O. Returning biochar to agricultural fields is an important measure to mitigate soil N2O emissions. Accurately quantifying the effect of biochar on the process of N2O production and its driving factors is critical for achieving N2O emission mitigation. Recently, stable isotope techniques such as isotope labeling, natural abundance, and site preference (SP) value, have been widely used to distinguish N2O production pathways. However, the different isotope methods have certain limitations in distinguishing N2O production in biochar-amended soils where it is difficult to identify the relative contribution of individual pathways for N2O production. This paper systematically reviews the pathways of soil N2O production (nitrification, nitrifier denitrification, bacterial denitrification, fungal denitrification, coupled nitrification-denitrification, dissimilatory nitrate reduction to ammonium and abiotic processes) and their response mechanism to the addition of biochar, as well as the development history and advantages of isotopes in differentiating N2O production pathways in biochar-amended soils. Moreover, the limitations of current research methods and future research directions are proposed. These results will help resolve how biochar affects different processes that lead to soil N2O generation and provide a scientific basis for sustainable agricultural carbon sequestration and the fulfilment of carbon neutrality goals.
Collapse
Affiliation(s)
- Huan Li
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, Guizhou Province, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yuan Tang
- School of Public Health, the Key Laboratory of Environmental Pollution Monitoring and Disease Control, Ministry of Education, Guizhou Medical University, Guiyang, 550025, Guizhou Province, China
| | - Weichang Gao
- Guizhou Academy of Tobacco Science, Guiyang, 550081, Guizhou Province, China
| | - Wenjie Pan
- Guizhou Academy of Tobacco Science, Guiyang, 550081, Guizhou Province, China
| | - Chaoying Jiang
- Guizhou Academy of Tobacco Science, Guiyang, 550081, Guizhou Province, China
| | - Xinqing Lee
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, Guizhou Province, China
| | - Jianzhong Cheng
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, Guizhou Province, China.
| |
Collapse
|
2
|
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.
Collapse
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
| |
Collapse
|
3
|
Chen X, Zhang S, Liu J, Wang J, Xin Y, Sun S, Xia X. Tracing Microbial Production and Consumption Sources of N 2O in Rivers on the Qinghai-Tibet Plateau via Isotopocule and Functional Microbe Analyses. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:7196-7205. [PMID: 37097256 DOI: 10.1021/acs.est.3c00950] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Nitrous oxide (N2O), a potent greenhouse gas, is produced in rivers through a series of microbial metabolic pathways. However, the microbial source of N2O production and the degree of N2O reduction in river systems are not well understood and quantified. This work investigated isotopic compositions (δ15N-N2O and δ18O-N2O) and N2O site preference as well as N2O-related microbial features, thereby differentiating the importance of nitrification, denitrification, and N2O reduction in controlling N2O emissions from five rivers on the eastern Qinghai-Tibet Plateau (EQTP). The average N2O concentration in overlying water (15.2 nmol L-1) was close to that in porewater (17.5 nmol L-1), suggesting that both overlying water and sediment are potentially important sources of N2O. Canonical and nitrifier denitrification dominated riverine N2O production, with contribution being approximately 90%. Nitrification is a non-negligible source of N2O production, and N2O concentration was positively correlated with nitrification genetic potential. The degree of N2O reduction ranged from 78.1 to 94.1% (averaging 90%), significantly exceeding the reported values (averaging 70%) in other freshwaters, which was attributed to the higher ratios of organic carbon to nitrogen and lower ratio of (nirS + nirK)/nosZ in EQTP rivers. This study indicates that a combination of isotopic and isotopocule values with functional microbe analysis is useful for quantifying the microbial sources of N2O in rivers, and the intense microbial reduction of N2O significantly accounts for the low N2O emissions observed in EQTP rivers, suggesting that both the production and consumption of N2O in rivers should be considered in the future.
Collapse
Affiliation(s)
- Xin Chen
- Key Laboratory of Water and Sediment Sciences of Ministry of Education, State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China
| | - Sibo Zhang
- Guangdong Provincial Key Laboratory of Water Quality Improvement and Ecological Restoration for Watersheds, Institute of Environmental and Ecological Engineering, Guangdong University of Technology, Guangzhou, Guangdong 510006, China
| | - Jiao Liu
- Key Laboratory of Water and Sediment Sciences of Ministry of Education, State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China
| | - Junfeng Wang
- Key Laboratory of Water and Sediment Sciences of Ministry of Education, State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China
| | - Yuan Xin
- Key Laboratory of Water and Sediment Sciences of Ministry of Education, State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China
| | - Siyue Sun
- Key Laboratory of Water and Sediment Sciences of Ministry of Education, State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China
| | - Xinghui Xia
- Key Laboratory of Water and Sediment Sciences of Ministry of Education, State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China
| |
Collapse
|
4
|
Li X, Qi M, Gao D, Liu M, Sardans J, Peñuelas J, Hou L. Nitrous oxide emissions from subtropical estuaries: Insights for environmental controls and implications. WATER RESEARCH 2022; 212:118110. [PMID: 35085843 DOI: 10.1016/j.watres.2022.118110] [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: 11/22/2021] [Revised: 01/05/2022] [Accepted: 01/18/2022] [Indexed: 06/14/2023]
Abstract
Estuaries are expected to contribute large nitrous oxide (N2O) emissions, however the environmental controls and implications of N2O emissions have not been well understood. Here we investigated water N2O concentrations, fluxes and sources in wet and dry seasons for 2019-2020 in five subtropical estuaries spanning hydrologic characteristics and nitrogen concentrations gradient. Water dissolved N2O concentrations and fluxes were in a range of 15.8-84.9 nmol L-1 and 0.66-22.2 µg m-2 h-1, respectively. These studied estuaries were oversaturated in N2O, with the saturations of 118-615%. Water dissolved N2O concentrations, saturations and fluxes increased significantly as nitrogen concentrations increase, whereas they did not differ significantly between the wet and dry seasons. Water N2O emissions, however, were also lower in the estuaries characterized by large discharge and water flow. N2O saturations and fluxes were determined directly by water nitrogen and oxygen concentrations and more indirectly by water temperature and velocity. The δ15N-N2O and site preference-N2O varied respectively from 2.86 to 11.31‰ and from 1.58 to 11.72‰, which overlapped the values between nitrification and denitrification. Nitrification and denitrification were responsible for 18.7-38.1% and 61.9-81.3% of N2O emissions, respectively. Indirect N2O emission factors were 0.08-0.14% and decreased with increasing total nitrogen concentrations. It is estimated that water N2O emissions in CO2 equiv could offset approximately 4.9% of average CO2 sink of China estuaries. Therefore, these results suggest that nitrogen concentrations and hydrologic characteristics together modify N2O emissions and that estuaries may be the important contributors to N2O emissions.
Collapse
Affiliation(s)
- Xiaofei Li
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200241, China; Key Laboratory for Humid Subtropical Eco-geographical Processes of the Ministry of Education, Fujian Normal University, Fuzhou 350007, China.
| | - Mengting Qi
- Key Laboratory for Humid Subtropical Eco-geographical Processes of the Ministry of Education, Fujian Normal University, Fuzhou 350007, China
| | - Dengzhou Gao
- State Key Laboratory of Estuarine and Coastal Research, 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
| | - Jordi Sardans
- CSIC, Global Ecology CREAF-CEAB-CSIC-UAB, Cerdanyola del Valles, Barcelona, Catalonia 08193, Spain; CREAF, Cerdanyola del Valles, Barcelona, Catalonia 08193, Spain
| | - Josep Peñuelas
- CSIC, Global Ecology CREAF-CEAB-CSIC-UAB, Cerdanyola del Valles, Barcelona, Catalonia 08193, Spain; CREAF, Cerdanyola del Valles, Barcelona, Catalonia 08193, Spain
| | - Lijun Hou
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200241, China.
| |
Collapse
|
5
|
Masuda S, Sato T, Mishima I, Maruo C, Yamazaki H, Nishimura O. Impact of nitrogen compound variability of sewage treated water on N 2O production in riverbeds. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2021; 290:112621. [PMID: 33901830 DOI: 10.1016/j.jenvman.2021.112621] [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: 12/28/2020] [Revised: 03/31/2021] [Accepted: 04/11/2021] [Indexed: 06/12/2023]
Abstract
Nitrous oxide (N2O), a strong greenhouse and ozone depleting gas, is known to be generated in the river environment. However, the impact of sewage treated water on the production mechanism has not been clarified. In this study, N2O production in the upper reach of a river was evaluated by field survey and activity test. The results demonstrated that the N2O production activity of the river pebbles increased with the inflow of the sewage treated water, which was supported by field survey results, such as the dissolved N2O concentrations and water quality. The emission factors of N2O were determined to be 0.02-0.05% in nitrification and 0.01-0.025% in denitrification. Our study shows that combining a field survey and an activity test improves the reliability of the results and leads to the appropriate quantitative evaluation. From a perspective of controlling the N2O emissions from the sewage treatment plant, N2O generation inside the plant is critical. However, appropriate nitrogen removal in the treatment plant is connected to the reduction of N2O generation in the river environment.
Collapse
Affiliation(s)
- Shuhei Masuda
- Department of Civil Engineering and Architecture, National Institute of Technology, Akita College, Bunkyo-cho 1-1, Iijima, Akita, Akita, Japan.
| | - Takemi Sato
- Department of Civil and Environmental Engineering, Tohoku University, Aoba 6-6-06, Aramaki, Aoba-ku, Sendai, Miyagi, Japan
| | - Iori Mishima
- Water Environment Group, Center for Environmental Science in Saitama, Kamitanadare 914, Kazo, Saitama, Japan; Graduate School of Science and Engineering, Saitama University, Shimo-Okubo 255, Sakura, Saitama, Saitama, Japan
| | - Chikako Maruo
- Technical Division, School of Engineering, Tohoku University, Aoba 6-6-06, Aramaki, Aoba-ku, Sendai, Miyagi, Japan
| | - Hiroshi Yamazaki
- Faculty of Science and Engineering, Toyo University, Kujirai, 2100, Saitama, Japan
| | - Osamu Nishimura
- Department of Civil and Environmental Engineering, Tohoku University, Aoba 6-6-06, Aramaki, Aoba-ku, Sendai, Miyagi, Japan
| |
Collapse
|
6
|
Chun Y, Kim D, Hattori S, Toyoda S, Yoshida N, Huh J, Lim JH, Park JH. Temperature control on wastewater and downstream nitrous oxide emissions in an urbanized river system. WATER RESEARCH 2020; 187:116417. [PMID: 32987292 DOI: 10.1016/j.watres.2020.116417] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 09/04/2020] [Accepted: 09/09/2020] [Indexed: 06/11/2023]
Abstract
Although eutrophic urban rivers receiving loads of wastewater represent an important anthropogenic source of N2O, little is known as to how temperature and other environmental factors affect temporal variations in N2O emissions from wastewater treatment plants (WWTPs) and downstream rivers. Two-year monitoring at a WWTP and five river sites was complemented with available water quality data, laboratory incubations, and stable isotopes in N2O and NO3- to explore how wastewater effluents interact with seasonal changes in environmental conditions to affect downstream metabolic processes and N2O emissions from the lower Han River traversing the megacity Seoul. Water quality data from four WWTPs revealed significant inverse relationships between water temperature and the concentrations or fluxes of total N (TN) in effluents. Increased TN fluxes at low temperatures concurred with N2O surges in WWTP effluents and downstream rivers, counteracting the long-term decline in TN fluxes resulting from enhanced wastewater treatments. Incubation experiments with river water and sediment, in isolation or combined, implied the hypoxic winter sediment as a large source of N2O, whereas the anoxic summer sediment produced a smaller amount of N2O only when it was added with oxic water. For both WWTP effluents and downstream rivers, bulk isotope ratios and intramolecular distribution of 15N in N2O distinctly differed between summer and winter, indicating incomplete denitrification in the hypoxic sediment at low temperatures as a primary downstream source adding to WWTP-derived N2O. Winter surges in wastewater TN and sediment N2O release highlight temperature variability as an underappreciated control over anthropogenic N2O emissions from increasingly urbanized river systems worldwide.
Collapse
Affiliation(s)
- Yewon Chun
- Department of Environmental Science and Engineering, Ewha Womans University, Seoul 03760, Republic of Korea
| | - Dohee Kim
- Department of Environmental Science and Engineering, Ewha Womans University, Seoul 03760, Republic of Korea
| | - Shohei Hattori
- Department of Chemical Science and Engineering, Tokyo Institute of Technology, Yokohama 226-8502, Japan
| | - Sakae Toyoda
- Department of Chemical Science and Engineering, Tokyo Institute of Technology, Yokohama 226-8502, Japan
| | - Naohiro Yoshida
- Department of Chemical Science and Engineering, Tokyo Institute of Technology, Yokohama 226-8502, Japan; Earth-Life Science Institute, Tokyo Institute of Technology, Tokyo 152-8550, Japan
| | - Jinhee Huh
- Department of Environmental Science and Engineering, Ewha Womans University, Seoul 03760, Republic of Korea
| | - Ju-Hee Lim
- Department of Environmental Science and Engineering, Ewha Womans University, Seoul 03760, Republic of Korea
| | - Ji-Hyung Park
- Department of Environmental Science and Engineering, Ewha Womans University, Seoul 03760, Republic of Korea.
| |
Collapse
|
7
|
Deng O, Li X, Xiao Y, Zhang S, Deng L, Lan T, Luo L, Gao X, Zhou W, Zhang J, Ling J. Emission of nitrous oxide from plain multi-ditch system and its impact factors. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2019; 26:16596-16605. [PMID: 30989602 DOI: 10.1007/s11356-019-04992-8] [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: 01/23/2019] [Accepted: 03/25/2019] [Indexed: 06/09/2023]
Abstract
Multi-level ditch area is a major component of the hydrographic net of plain area, China. Given the high concentration of nitrogen (N) in the surface water and vigorous biogeochemical interactions, ditch is likely to be the hot spots of N2O emission. However, N2O emission flux and emission factor (EF5r) of multi-level ditches have not been determined. To address this knowledge gap, a 1-year field work in three ditches with different levels in Chengdu Plain was conducted. It is found that the annual flux of N2O emission and EF5r was higher in the lateral (0.0020 and 83.94 μg m-2 h-1) and field ditches (0.0019 and 110.75 μg m-2 h-1) than in the branch ditch (0.0016 and 46.38 μg m-2 h-1, P < 0.05). It is found that parameters of groundwater level, discharge, precipitation, and NH4+ were the primary factors, and these parameters can model the N2O flux well. Furthermore, the content of NH4+ in the surface water of ditches presented better correlation with the emission of N2O than the content of NO3-. Therefore, controlling NH4+ emission and lessening fertilizer usage in summer may be key solutions for indirect reduction of N2O in Chengdu Plain.
Collapse
Affiliation(s)
- Ouping Deng
- College of Resources, Sichuan Agricultural University, Chengdu, 611130, People's Republic of China
| | - Xi Li
- College of Resources, Sichuan Agricultural University, Chengdu, 611130, People's Republic of China
| | - Yinlong Xiao
- College of Environmental Science, Sichuan Agricultural University, Chengdu, 611130, People's Republic of China
| | - Shirong Zhang
- College of Environmental Science, Sichuan Agricultural University, Chengdu, 611130, People's Republic of China
| | - Liangji Deng
- College of Resources, Sichuan Agricultural University, Chengdu, 611130, People's Republic of China
| | - Ting Lan
- College of Resources, Sichuan Agricultural University, Chengdu, 611130, People's Republic of China
| | - Ling Luo
- College of Environmental Science, Sichuan Agricultural University, Chengdu, 611130, People's Republic of China
| | - Xuesong Gao
- College of Resources, Sichuan Agricultural University, Chengdu, 611130, People's Republic of China
| | - Wei Zhou
- College of Resources, Sichuan Agricultural University, Chengdu, 611130, People's Republic of China
| | - Jing Zhang
- College of Environmental Science, Sichuan Agricultural University, Chengdu, 611130, People's Republic of China
| | - Jing Ling
- College of Resources, Sichuan Agricultural University, Chengdu, 611130, People's Republic of China.
| |
Collapse
|
8
|
Tumendelger A, Alshboul Z, Lorke A. Methane and nitrous oxide emission from different treatment units of municipal wastewater treatment plants in Southwest Germany. PLoS One 2019; 14:e0209763. [PMID: 30608974 PMCID: PMC6319721 DOI: 10.1371/journal.pone.0209763] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Accepted: 12/11/2018] [Indexed: 11/27/2022] Open
Abstract
We measured the atmospheric emission rates of methane (CH4) and nitrous oxide (N2O) in two wastewater treatment plants in Southwest Germany, which apply different treatment technologies. Dissolved gas concentrations and fluxes were measured during all processing steps as well as in the discharge receiving streams. N2O isotopocule analysis revealed that NH2OH oxidation during nitrification contributed 86–96% of the N2O production in the nitrification tank, whereas microbial denitrification was the main production pathway in the denitrification tank in a conventional activated sludge (CAS) system. During wastewater treatment using a modified Ludzack-Ettinger system (MLE) with energy recovery, N2O was predominantly produced by the NO2- reduction by nitrifier-denitrification process. For both systems, N2O emissions were low, with emission factors of 0.008% and 0.001% for the MLE and the CAS system, respectively. In the effluent-receiving streams, bacterial denitrification and nitrification contributed nearly equally to N2O production. The CH4 emission from the MLE system was estimated as 118.1 g-C d-1, which corresponds to an emission factor of 0.004%, and was three times lower than the emission from the CAS system with 0.01%.
Collapse
Affiliation(s)
- Azzaya Tumendelger
- Institute of Chemistry and Chemical Technology, Mongolian Academy of Sciences, Bayanzurkh district, Ulaanbaatar, Mongolia
- Institute for Environmental Sciences, University of Koblenz-Landau, Landau, Germany
- * E-mail:
| | - Zeyad Alshboul
- Institute for Environmental Sciences, University of Koblenz-Landau, Landau, Germany
- Civil Engineering Department, Faculty of Engineering, Applied Science University, Amman, Jordan
| | - Andreas Lorke
- Institute for Environmental Sciences, University of Koblenz-Landau, Landau, Germany
| |
Collapse
|
9
|
Wang G, Wang J, Xia X, Zhang L, Zhang S, McDowell WH, Hou L. Nitrogen removal rates in a frigid high-altitude river estimated by measuring dissolved N 2 and N 2O. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 645:318-328. [PMID: 30025239 DOI: 10.1016/j.scitotenv.2018.07.090] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Revised: 07/06/2018] [Accepted: 07/07/2018] [Indexed: 06/08/2023]
Abstract
Rivers are important sites of both nitrogen removal and emission of nitrous oxide (N2O), a powerful greenhouse gas. Previous measurements have focused on nitrogen-rich temperate rivers, with cold, low-nitrogen river systems at high-altitude receiving less attention. Here, nitrogen removal rates were estimated by directly measuring dissolved N2 and N2O of the Yellow River in its source region of the Tibetan Plateau, a frigid high-altitude environment. We measured the dissolved N2 and N2O using N2:Ar ratio method and headspace equilibrium technique, respectively. Dissolved N2 in the river water ranged from 337 to 513 μmol N2 L-1, and dissolved N2O ranged from 10.4 to 15.4 nmol N2O L-1. Excess dissolved N2 (△N2) ranged from -8.6 to 10.5 μmol N2 L-1, while excess dissolved N2O (△N2O) ranged from 2.1 to 8.3 nmol N2O L-1; they were relatively low compared with most other rivers in the world. However, N2 removal fraction (△N2/DIN, average 21.6%) and EF5r values (N2O - N/NO3 - N, range 1.6 × 10-4-5.0 × 10-2) were comparable with many other rivers despite the high altitude for the Yellow River source region. Furthermore, the EF5r values increased with altitude. Estimated fluxes of N2 and N2O to the atmosphere from the river surface ranged from -67.5 to 93.5 mmol N m-2 d-1 and from 4.8 to 93.8 μmol N m-2 d-1, respectively, and the nitrogen removal from rivers was estimated to be 1.87 × 107 kg N yr-1 for the Yellow River source region. This is the first report of nitrogen removal for a frigid high-altitude river; the results suggest that N removal and N2O emission from cold high-altitude rivers should be considered in the global nitrogen budget.
Collapse
Affiliation(s)
- Gongqin Wang
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China
| | - Junfeng Wang
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China
| | - Xinghui Xia
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China.
| | - Liwei Zhang
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China
| | - Sibo Zhang
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China
| | - William H McDowell
- Department of Natural Resources and the Environment, University of New Hampshire, Durham, NH 03824, USA
| | - Lijun Hou
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200062, China
| |
Collapse
|
10
|
Masuda S, Otomo S, Maruo C, Nishimura O. Contribution of dissolved N 2O in total N 2O emission from sewage treatment plant. CHEMOSPHERE 2018; 212:821-827. [PMID: 30193230 DOI: 10.1016/j.chemosphere.2018.08.089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Revised: 07/20/2018] [Accepted: 08/18/2018] [Indexed: 06/08/2023]
Abstract
The characteristics of nitrous oxide, N2O, from a sewage treatment plant, which conducts nitrogen removal, and the river that receives its effluent water, were investigated by intensive daily surveys in summer and winter. N2O production in the sewage treatment plant was promoted in winter when nitrite accumulated in the reaction tank. The dissolved N2O concentration in the effluent water was also high in winter, which caused the dissolved N2O concentration to increase in the river downstream. In contrast, the N2O production inside the plant and the dissolved N2O emission through the effluent water, the dissolved N2O discharge, was controlled in summer when the nitrogen removal was more complete and there was no-nitrite accumulation. The dissolved N2O in the effluent water was rapidly lost after leaving the plant by as much as 26% in summer and 59% in winter. Additionally, the amount of the dissolved N2O discharge in winter was almost equal to that of the indirect N2O emission. When the nitrogen removal proceeded successfully, the amount of dissolved N2O discharge was small. In contrast, when the nitrogen removal was insufficient, the dissolved N2O discharge became an important N2O source.
Collapse
Affiliation(s)
- Shuhei Masuda
- Department of Civil Engineering and Architecture, National Institute of Technology, Akita College, Bunkyo-cho 1-1, Iijima, Akita, Akita, Japan.
| | - Shohei Otomo
- Technology Education Support Center, National Institute of Technology, Akita College, Bunkyo-cho 1-1, Iijima, Akita, Akita, Japan
| | - Chikako Maruo
- Technical Division, School of Engineering, Tohoku University, Aoba 6-6-06, Aobayama, Aoba-ku, Sendai, Miyagi, Japan
| | - Osamu Nishimura
- Department of Civil and Environmental Engineering, Tohoku University, Aoba 6-6-06, Aobayama, Aoba-ku, Sendai, Miyagi, Japan
| |
Collapse
|
11
|
Duan H, Ye L, Erler D, Ni BJ, Yuan Z. Quantifying nitrous oxide production pathways in wastewater treatment systems using isotope technology - A critical review. WATER RESEARCH 2017; 122:96-113. [PMID: 28595125 DOI: 10.1016/j.watres.2017.05.054] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Revised: 05/01/2017] [Accepted: 05/25/2017] [Indexed: 06/07/2023]
Abstract
Nitrous oxide (N2O) is an important greenhouse gas and an ozone-depleting substance which can be emitted from wastewater treatment systems (WWTS) causing significant environmental impacts. Understanding the N2O production pathways and their contribution to total emissions is the key to effective mitigation. Isotope technology is a promising method that has been applied to WWTS for quantifying the N2O production pathways. Within the scope of WWTS, this article reviews the current status of different isotope approaches, including both natural abundance and labelled isotope approaches, to N2O production pathways quantification. It identifies the limitations and potential problems with these approaches, as well as improvement opportunities. We conclude that, while the capabilities of isotope technology have been largely recognized, the quantification of N2O production pathways with isotope technology in WWTS require further improvement, particularly in relation to its accuracy and reliability.
Collapse
Affiliation(s)
- Haoran Duan
- Advanced Water Management Centre, The University of Queensland, St. Lucia, Brisbane, QLD 4072, Australia
| | - Liu Ye
- School of Chemical Engineering, The University of Queensland, St. Lucia, Brisbane, QLD 4072, Australia
| | - Dirk Erler
- Centre for Coastal Biogeochemistry, School of Environmental Science and Engineering, Southern Cross University, Lismore, NSW 2480 Australia
| | - Bing-Jie Ni
- Advanced Water Management Centre, The University of Queensland, St. Lucia, Brisbane, QLD 4072, Australia
| | - Zhiguo Yuan
- Advanced Water Management Centre, The University of Queensland, St. Lucia, Brisbane, QLD 4072, Australia.
| |
Collapse
|
12
|
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.
Collapse
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
| |
Collapse
|
13
|
Hu M, Chen D, Dahlgren RA. Modeling nitrous oxide emission from rivers: a global assessment. GLOBAL CHANGE BIOLOGY 2016; 22:3566-3582. [PMID: 27170579 DOI: 10.1111/gcb.13351] [Citation(s) in RCA: 76] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Revised: 04/10/2016] [Accepted: 05/01/2016] [Indexed: 06/05/2023]
Abstract
Estimates of global riverine nitrous oxide (N2 O) emissions contain great uncertainty. We conducted a meta-analysis incorporating 169 observations from published literature to estimate global riverine N2 O emission rates and emission factors. Riverine N2 O flux was significantly correlated with NH4 , NO3 and DIN (NH4 + NO3 ) concentrations, loads and yields. The emission factors EF(a) (i.e., the ratio of N2 O emission rate and DIN load) and EF(b) (i.e., the ratio of N2 O and DIN concentrations) values were comparable and showed negative correlations with nitrogen concentration, load and yield and water discharge, but positive correlations with the dissolved organic carbon : DIN ratio. After individually evaluating 82 potential regression models based on EF(a) or EF(b) for global, temperate zone and subtropical zone datasets, a power function of DIN yield multiplied by watershed area was determined to provide the best fit between modeled and observed riverine N2 O emission rates (EF(a): R2 = 0.92 for both global and climatic zone models, n = 70; EF(b): R2 = 0.91 for global model and R2 = 0.90 for climatic zone models, n = 70). Using recent estimates of DIN loads for 6400 rivers, models estimated global riverine N2 O emission rates of 29.6-35.3 (mean = 32.2) Gg N2 O-N yr-1 and emission factors of 0.16-0.19% (mean = 0.17%). Global riverine N2 O emission rates are forecasted to increase by 35%, 25%, 18% and 3% in 2050 compared to the 2000s under the Millennium Ecosystem Assessment's Global Orchestration, Order from Strength, Technogarden, and Adapting Mosaic scenarios, respectively. Previous studies may overestimate global riverine N2 O emission rates (300-2100 Gg N2 O-N yr-1 ) because they ignore declining emission factor values with increasing nitrogen levels and channel size, as well as neglect differences in emission factors corresponding to different nitrogen forms. Riverine N2 O emission estimates will be further enhanced through refining emission factor estimates, extending measurements longitudinally along entire river networks and improving estimates of global riverine nitrogen loads.
Collapse
Affiliation(s)
- Minpeng Hu
- College of Environmental & Resource Sciences, Zhejiang University, Hangzhou, 310058, China
- Zhejiang Provincial Key Laboratory of Subtropical Soil and Plant Nutrition, Zhejiang University, Hangzhou, 310058, China
| | - Dingjiang Chen
- College of Environmental & Resource Sciences, Zhejiang University, Hangzhou, 310058, China.
- Ministry of Education Key Laboratory of Environment Remediation and Ecological Health, Zhejiang University, Hangzhou, 310058, China.
| | - Randy A Dahlgren
- Department of Land, Air, and Water Resources, University of California, Davis, CA, 95616, USA
| |
Collapse
|
14
|
Snider DM, Venkiteswaran JJ, Schiff SL, Spoelstra J. From the ground up: global nitrous oxide sources are constrained by stable isotope values. PLoS One 2015; 10:e0118954. [PMID: 25811179 PMCID: PMC4374930 DOI: 10.1371/journal.pone.0118954] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Accepted: 01/08/2015] [Indexed: 11/18/2022] Open
Abstract
Rising concentrations of nitrous oxide (N2O) in the atmosphere are causing widespread concern because this trace gas plays a key role in the destruction of stratospheric ozone and it is a strong greenhouse gas. The successful mitigation of N2O emissions requires a solid understanding of the relative importance of all N2O sources and sinks. Stable isotope ratio measurements (δ15N-N2O and δ18O-N2O), including the intramolecular distribution of 15N (site preference), are one way to track different sources if they are isotopically distinct. ‘Top-down’ isotope mass-balance studies have had limited success balancing the global N2O budget thus far because the isotopic signatures of soil, freshwater, and marine sources are poorly constrained and a comprehensive analysis of global N2O stable isotope measurements has not been done. Here we used a robust analysis of all available in situ measurements to define key global N2O sources. We showed that the marine source is isotopically distinct from soil and freshwater N2O (the continental source). Further, the global average source (sum of all natural and anthropogenic sources) is largely controlled by soils and freshwaters. These findings substantiate past modelling studies that relied on several assumptions about the global N2O cycle. Finally, a two-box-model and a Bayesian isotope mixing model revealed marine and continental N2O sources have relative contributions of 24–26% and 74–76% to the total, respectively. Further, the Bayesian modeling exercise indicated the N2O flux from freshwaters may be much larger than currently thought.
Collapse
Affiliation(s)
- David M. Snider
- National Water Research Institute, Canada Centre for Inland Waters, Environment Canada, Burlington, ON, L7R 4A6, Canada
- * E-mail: (DMS); (JJV)
| | - Jason J. Venkiteswaran
- Department of Geography and Environmental Studies, Wilfrid Laurier University, Waterloo, ON, N2L 3C5, Canada
- Department of Earth and Environmental Sciences, University of Waterloo, Waterloo, ON, N2L 3G1, Canada
- * E-mail: (DMS); (JJV)
| | - Sherry L. Schiff
- Department of Earth and Environmental Sciences, University of Waterloo, Waterloo, ON, N2L 3G1, Canada
| | - John Spoelstra
- National Water Research Institute, Canada Centre for Inland Waters, Environment Canada, Burlington, ON, L7R 4A6, Canada
- Department of Earth and Environmental Sciences, University of Waterloo, Waterloo, ON, N2L 3G1, Canada
| |
Collapse
|
15
|
Musenze RS, Werner U, Grinham A, Udy J, Yuan Z. Methane and nitrous oxide emissions from a subtropical coastal embayment (Moreton Bay, Australia). J Environ Sci (China) 2015; 29:82-96. [PMID: 25766016 DOI: 10.1016/j.jes.2014.06.049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Revised: 05/18/2014] [Accepted: 06/14/2014] [Indexed: 06/04/2023]
Abstract
Surface water methane (CH4) and nitrous oxide (N2O) concentrations and fluxes were investigated in two subtropical coastal embayments (Bramble Bay and Deception Bay, which are part of the greater Moreton Bay, Australia). Measurements were done at 23 stations in seven campaigns covering different seasons during 2010-2012. Water-air fluxes were estimated using the Thin Boundary Layer approach with a combination of wind and currents-based models for the estimation of the gas transfer velocities. The two bays were strong sources of both CH4 and N2O with no significant differences in the degree of saturation of both gases between them during all measurement campaigns. Both CH4 and N2O concentrations had strong temporal but minimal spatial variability in both bays. During the seven seasons, CH4 varied between 500% and 4000% saturation while N2O varied between 128 and 255% in the two bays. Average seasonal CH4 fluxes for the two bays varied between 0.5±0.2 and 6.0±1.5 mg CH4/(m2·day) while N2O varied between 0.4±0.1 and 1.6±0.6 mg N2O/(m2·day). Weighted emissions (t CO2-e) were 63%-90% N2O dominated implying that a reduction in N2O inputs and/or nitrogen availability in the bays may significantly reduce the bays' greenhouse gas (GHG) budget. Emissions data for tropical and subtropical systems is still scarce. This work found subtropical bays to be significant aquatic sources of both CH4 and N2O and puts the estimated fluxes into the global context with measurements done from other climatic regions.
Collapse
Affiliation(s)
- Ronald S Musenze
- Advanced Water Management Centre (AWMC), The University of Queensland, Brisbane, Qld 4072, Australia.
| | - Ursula Werner
- Advanced Water Management Centre (AWMC), The University of Queensland, Brisbane, Qld 4072, Australia
| | - Alistair Grinham
- Advanced Water Management Centre (AWMC), The University of Queensland, Brisbane, Qld 4072, Australia; School of Civil Engineering, The University of Queensland, Brisbane, Qld 4072, Australia
| | - James Udy
- Healthy Waterways Ltd., Brisbane, Qld 4003, Australia
| | - Zhiguo Yuan
- Advanced Water Management Centre (AWMC), The University of Queensland, Brisbane, Qld 4072, Australia.
| |
Collapse
|
16
|
Tumendelger A, Toyoda S, Yoshida N. Isotopic analysis of N2O produced in a conventional wastewater treatment system operated under different aeration conditions. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2014; 28:1883-1892. [PMID: 25088132 DOI: 10.1002/rcm.6973] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Revised: 05/21/2014] [Accepted: 06/23/2014] [Indexed: 06/03/2023]
Abstract
RATIONALE Dissolved oxygen (DO) concentration is a key parameter of nitrous oxide (N2O), a greenhouse gas, emitted from wastewater treatment systems. No study of stable isotopes has described N2O production during conventional activated sludge (CAS) treatment under different DO concentrations. METHODS Concentrations and isotope ratios, including intramolecular site preference of (15)N in NNO (SP), of N2O were measured using gas chromatography/isotope ratio mass spectrometry (GC/IRMS) for samples from seven points in a wastewater treatment plant (WWTP) operated with three aeration conditions. The δ(15)N values of NH4(+) and the δ(15)N and δ(18)O values of NO3(-) were measured using IRMS. RESULTS Aeration tank water was supersaturated with N2O. The highest value, 3700 nmol kg(-1), was observed at the aeration tank end and in settled sludge under the lowest aeration condition. About 0.03% of the influent NH4(+) was emitted as gaseous N2O at the lowest aeration condition. The conversion rate was 0.14% under the highest aeration condition. The SP values were significantly higher at the middle and end of the aeration tanks under the highest aeration condition, but were nearly zero or slightly negative under lower aeration conditions. CONCLUSIONS Under the highest aeration condition, NH2OH oxidation (nitrification) was the main contributor to N2O production at about 90% and 57%, respectively, at the aeration tank middle and end. At other sampling points, 55-63% of the N2O was produced by bacterial NO2(-) reduction (nitrifier-denitrification) with a lower nitrification contribution. For all sampling points in the lower aeration experiments, NO2(-) reduction was a major N2O production pathway.
Collapse
Affiliation(s)
- Azzaya Tumendelger
- Department of Environmental Chemistry and Engineering, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama, 226-8502, Japan
| | | | | |
Collapse
|
17
|
Thuss SJ, Venkiteswaran JJ, Schiff SL. Proper interpretation of dissolved nitrous oxide isotopes, production pathways, and emissions requires a modelling approach. PLoS One 2014; 9:e90641. [PMID: 24608915 PMCID: PMC3946536 DOI: 10.1371/journal.pone.0090641] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Accepted: 02/03/2014] [Indexed: 11/18/2022] Open
Abstract
Stable isotopes ([Formula: see text]15N and [Formula: see text]18O) of the greenhouse gas N2O provide information about the sources and processes leading to N2O production and emission from aquatic ecosystems to the atmosphere. In turn, this describes the fate of nitrogen in the aquatic environment since N2O is an obligate intermediate of denitrification and can be a by-product of nitrification. However, due to exchange with the atmosphere, the [Formula: see text] values at typical concentrations in aquatic ecosystems differ significantly from both the source of N2O and the N2O emitted to the atmosphere. A dynamic model, SIDNO, was developed to explore the relationship between the isotopic ratios of N2O, N2O source, and the emitted N2O. If the N2O production rate or isotopic ratios vary, then the N2O concentration and isotopic ratios may vary or be constant, not necessarily concomitantly, depending on the synchronicity of production rate and source isotopic ratios. Thus prima facie interpretation of patterns in dissolved N2O concentrations and isotopic ratios is difficult. The dynamic model may be used to correctly interpret diel field data and allows for the estimation of the gas exchange coefficient, N2O production rate, and the production-weighted [Formula: see text] values of the N2O source in aquatic ecosystems. Combining field data with these modelling efforts allows this critical piece of nitrogen cycling and N2O flux to the atmosphere to be assessed.
Collapse
Affiliation(s)
- Simon J. Thuss
- Department of Earth and Environmental Sciences, University of Waterloo, Waterloo, Ontario, Canada
| | - Jason J. Venkiteswaran
- Department of Earth and Environmental Sciences, University of Waterloo, Waterloo, Ontario, Canada
- * E-mail:
| | - Sherry L. Schiff
- Department of Earth and Environmental Sciences, University of Waterloo, Waterloo, Ontario, Canada
| |
Collapse
|
18
|
Musenze RS, Werner U, Grinham A, Udy J, Yuan Z. Methane and nitrous oxide emissions from a subtropical estuary (the Brisbane River estuary, Australia). THE SCIENCE OF THE TOTAL ENVIRONMENT 2014; 472:719-729. [PMID: 24333994 DOI: 10.1016/j.scitotenv.2013.11.085] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2013] [Revised: 10/21/2013] [Accepted: 11/17/2013] [Indexed: 06/03/2023]
Abstract
Methane (CH4) and nitrous oxide (N2O) are two key greenhouse gases. Their global atmospheric budgeting is, however, flout with challenges partly due to lack of adequate field studies determining the source strengths. Knowledge and data limitations exist for subtropical and tropical regions especially in the southern latitudes. Surface water methane and nitrous oxide concentrations were measured in a subtropical estuarine system in the southern latitudes in an extensive field study from 2010 to 2012 and water-air fluxes estimated using models considering the effects of both wind and flow induced turbulence. The estuary was found to be a strong net source of both CH4 and N2O all-year-round. Dissolved N2O concentrations ranged between 9.1 ± 0.4 to 45.3 ± 1.3 nM or 135 to 435% of atmospheric saturation level, while CH4 concentrations varied between 31.1 ± 3.7 to 578.4 ± 58.8 nM or 1210 to 26,430% of atmospheric saturation level. These results compare well with measurements from tropical estuarine systems. There was strong spatial variability with both CH4 and N2O concentrations increasing upstream the estuary. Strong temporal variability was also observed but there were no clear seasonal patterns. The degree of N2O saturation significantly increased with NOx concentrations (r(2)=0.55). The estimated water-air fluxes varied between 0.1 and 3.4 mg N2O m(-2)d(-1) and 0.3 to 27.9 mg CH4 m(-2)d(-1). Total emissions (CO2-e) were N2O (64%) dominated, highlighting the need for reduced nitrogen inputs into the estuary. Choice of the model(s) for estimation of the gas transfer velocity had a big bearing on the estimated total emissions.
Collapse
Affiliation(s)
- Ronald S Musenze
- Advanced Water Management Centre (AWMC), the University of Queensland, Brisbane, Qld 4072, Australia
| | - Ursula Werner
- Advanced Water Management Centre (AWMC), the University of Queensland, Brisbane, Qld 4072, Australia
| | - Alistair Grinham
- Advanced Water Management Centre (AWMC), the University of Queensland, Brisbane, Qld 4072, Australia; School of Civil Engineering, the University of Queensland, Brisbane, Qld 4072, Australia
| | - James Udy
- Healthy Waterways Ltd, P.O. Box 13086, George Street, Brisbane, Qld 4003, Australia
| | - Zhiguo Yuan
- Advanced Water Management Centre (AWMC), the University of Queensland, Brisbane, Qld 4072, Australia.
| |
Collapse
|
19
|
Rathnayake RMLD, Song Y, Tumendelger A, Oshiki M, Ishii S, Satoh H, Toyoda S, Yoshida N, Okabe S. Source identification of nitrous oxide on autotrophic partial nitrification in a granular sludge reactor. WATER RESEARCH 2013; 47:7078-7086. [PMID: 24200002 DOI: 10.1016/j.watres.2013.07.055] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2013] [Revised: 06/19/2013] [Accepted: 07/04/2013] [Indexed: 06/02/2023]
Abstract
Emission of nitrous oxide (N2O) during biological wastewater treatment is of growing concern since N2O is a major stratospheric ozone-depleting substance and an important greenhouse gas. The emission of N2O from a lab-scale granular sequencing batch reactor (SBR) for partial nitrification (PN) treating synthetic wastewater without organic carbon was therefore determined in this study, because PN process is known to produce more N2O than conventional nitrification processes. The average N2O emission rate from the SBR was 0.32 ± 0.17 mg-N L(-1) h(-1), corresponding to the average emission of N2O of 0.8 ± 0.4% of the incoming nitrogen load (1.5 ± 0.8% of the converted NH4(+)). Analysis of dynamic concentration profiles during one cycle of the SBR operation demonstrated that N2O concentration in off-gas was the highest just after starting aeration whereas N2O concentration in effluent was gradually increased in the initial 40 min of the aeration period and was decreased thereafter. Isotopomer analysis was conducted to identify the main N2O production pathway in the reactor during one cycle. The hydroxylamine (NH2OH) oxidation pathway accounted for 65% of the total N2O production in the initial phase during one cycle, whereas contribution of the NO2(-) reduction pathway to N2O production was comparable with that of the NH2OH oxidation pathway in the latter phase. In addition, spatial distributions of bacteria and their activities in single microbial granules taken from the reactor were determined with microsensors and by in situ hybridization. Partial nitrification occurred mainly in the oxic surface layer of the granules and ammonia-oxidizing bacteria were abundant in this layer. N2O production was also found mainly in the oxic surface layer. Based on these results, although N2O was produced mainly via NH2OH oxidation pathway in the autotrophic partial nitrification reactor, N2O production mechanisms were complex and could involve multiple N2O production pathways.
Collapse
Affiliation(s)
- R M L D Rathnayake
- Division of Environmental Engineering, Faculty of Engineering, Hokkaido University, North-13, West-8, Sapporo 060-8628, Japan.
| | | | | | | | | | | | | | | | | |
Collapse
|
20
|
Yu Z, Deng H, Wang D, Ye M, Tan Y, Li Y, Chen Z, Xu S. Nitrous oxide emissions in the Shanghai river network: implications for the effects of urban sewage and IPCC methodology. GLOBAL CHANGE BIOLOGY 2013; 19:2999-3010. [PMID: 23907853 DOI: 10.1111/gcb.12290] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Accepted: 05/26/2013] [Indexed: 06/02/2023]
Abstract
Global nitrogen (N) enrichment has resulted in increased nitrous oxide (N(2)O) emission that greatly contributes to climate change and stratospheric ozone destruction, but little is known about the N(2)O emissions from urban river networks receiving anthropogenic N inputs. We examined N(2)O saturation and emission in the Shanghai city river network, covering 6300 km(2), over 27 months. The overall mean saturation and emission from 87 locations was 770% and 1.91 mg N(2)O-N m(-2) d(-1), respectively. Nitrous oxide (N(2)O) saturation did not exhibit a clear seasonality, but the temporal pattern was co-regulated by both water temperature and N loadings. Rivers draining through urban and suburban areas receiving more sewage N inputs had higher N(2)O saturation and emission than those in rural areas. Regression analysis indicated that water ammonium (NH(4)(+)) and dissolved oxygen (DO) level had great control on N(2)O production and were better predictors of N(2)O emission in urban watershed. About 0.29 Gg N(2)O-N yr(-1) N(2)O was emitted from the Shanghai river network annually, which was about 131% of IPCC's prediction using default emission values. Given the rapid progress of global urbanization, more study efforts, particularly on nitrification and its N(2)O yielding, are needed to better quantify the role of urban rivers in global riverine N(2)O emission.
Collapse
Affiliation(s)
- Zhongjie Yu
- Department of Geography, School of Resources and Environment Science, East China Normal University, Shanghai, 200062, China
| | | | | | | | | | | | | | | |
Collapse
|
21
|
Potter KE, Ono S, Prinn RG. Fully automated, high-precision instrumentation for the isotopic analysis of tropospheric N2O using continuous flow isotope ratio mass spectrometry. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2013; 27:1723-1738. [PMID: 23821566 DOI: 10.1002/rcm.6623] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2013] [Revised: 05/06/2013] [Accepted: 05/07/2013] [Indexed: 06/02/2023]
Abstract
RATIONALE Measurements of the isotopic composition of nitrous oxide in the troposphere have the potential to bring new information about the uncertain N2O budget, which mole fraction data alone have not been able to resolve. Characterizing the expected subtle variations in tropospheric N2O isotopic composition demands high-precision and high-frequency measurements. To enable useful observations of N2O isotopic composition in tropospheric air to reduce N2O source and sink uncertainty, it was necessary to develop a high-precision measurement system with fully automated capabilities for autonomous deployment at remote research stations. METHODS A fully automated pre-concentration system for high-precision measurements of N2O isotopic composition (δ(15)N(β) , δ(15)N(α), δ(18)O) in tropospheric air has been developed which combines a custom liquid-cryogen-free cryo-trapping system and gas chromatograph interfaced to a continuous flow isotope ratio mass spectrometry (IRMS) system. A quadrupole mass spectrometer was coupled in parallel to the IRMS system during development to evaluate peak interference. Multi-port inlet and fully-automated capabilities allow streamlined analyses between in situ air inlet, air standards, flask air sample, or other gas source in exactly replicated analysis sequences. RESULTS The system has the highest precision to date for (15)N site-specific composition results (δ(15) N(α) ±0.11‰, δ(15)N(β) ±0.14‰ (1σ)), attributed mostly to uniformity of analytical cycles and particular attention to fluorocarbon interference noted for (15)N site-specific measurements by IRMS. Air measurements demonstrated the fully automated capacity and performance. CONCLUSIONS The system makes substantial headway in measurement precision, possibly defining the limits of IRMS measurement capabilities in low concentration N2O air samples, with fully automated capabilities to enable high-frequency in situ measurements.
Collapse
Affiliation(s)
- Katherine E Potter
- Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139, USA.
| | | | | |
Collapse
|
22
|
Wunderlin P, Lehmann MF, Siegrist H, Tuzson B, Joss A, Emmenegger L, Mohn J. Isotope signatures of N₂O in a mixed microbial population system: constraints on N₂O producing pathways in wastewater treatment. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2013; 47:1339-48. [PMID: 23249174 DOI: 10.1021/es303174x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
We present measurements of site preference (SP) and bulk (15)N/(14)N ratios (δ(15)N(bulk)(N2O)) of nitrous oxide (N(2)O) by quantum cascade laser absorption spectroscopy (QCLAS) as a powerful tool to investigate N(2)O production pathways in biological wastewater treatment. QCLAS enables high-precision N(2)O isotopomer analysis in real time. This allowed us to trace short-term fluctuations in SP and δ(15)N(bulk)(N2O) and, hence, microbial transformation pathways during individual batch experiments with activated sludge from a pilot-scale facility treating municipal wastewater. On the basis of previous work with microbial pure cultures, we demonstrate that N(2)O emitted during ammonia (NH(4)(+)) oxidation with a SP of -5.8 to 5.6 ‰ derives mostly from nitrite (NO(2)(-)) reduction (e.g., nitrifier denitrification), with a minor contribution from hydroxylamine (NH(2)OH) oxidation at the beginning of the experiments. SP of N(2)O produced under anoxic conditions was always positive (1.2 to 26.1 ‰), and SP values at the high end of this spectrum (24.9 to 26.1 ‰) are indicative of N(2)O reductase activity. The measured δ(15)N(bulk)(N2O) at the initiation of the NH(4)(+) oxidation experiments ranged between -42.3 and -57.6 ‰ (corresponding to a nitrogen isotope effect Δδ(15)N = δ(15)N(substrate) - δ(15)N(bulk)(N2O) of 43.5 to 58.8 ‰), which is considerably higher than under denitrifying conditions (δ(15)N(bulk)(N2O) 2.4 to -17 ‰; Δδ(15)N = 0.1 to 19.5 ‰). During the course of all NH(4)(+) oxidation and nitrate (NO(3)(-)) reduction experiments, δ(15)N(bulk)(N2O) increased significantly, indicating net (15)N enrichment in the dissolved inorganic nitrogen substrates (NH(4)(+), NO(3)(-)) and transfer into the N(2)O pool. The decrease in δ(15)N(bulk)(N2O) during NO(2)(-) and NH(2)OH oxidation experiments is best explained by inverse fractionation during the oxidation of NO(2)(-) to NO(3)(-).
Collapse
Affiliation(s)
- Pascal Wunderlin
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Ueberlandstrasse 133, P.O. Box 611, 8600 Duebendorf, Switzerland.
| | | | | | | | | | | | | |
Collapse
|
23
|
Hinshaw SE, Dahlgren RA. Dissolved nitrous oxide concentrations and fluxes from the eutrophic San Joaquin River, California. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2013; 47:1313-1322. [PMID: 23259867 DOI: 10.1021/es301373h] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Agriculturally impacted ecosystems can be a source of the greenhouse gas, nitrous oxide (N(2)O); yet in situ measurements of N(2)O fluxes are sparse, particularly in streams and rivers. Dissolved N(2)O was measured from 9 sites over a 13-month period and a gas exchange model was used to predict N(2)O fluxes. N(2)O fluxes were measured at 4 sites on 7 sampling dates using floating chambers. In addition, dissolved N(2)O in porewaters was measured at 4 sites at various depths from 2 to 30 cm. Dissolved N(2)O-N concentrations in surface waters (0.31-1.60 μg L(-1)) varied seasonally with highest concentrations in late fall and early summer and lowest in winter. Estimated N(2)O-N fluxes (26.2-207 μg m(-2) hr(-1)) were in relative agreement with measured N(2)O fluxes using floating chambers (9.5-372 μg m(-2) hr(-1)) and correlated strongly with temperature and nitrate concentrations (R(2) = 0.86). Maximum dissolved N(2)O-N:NO(3)(-)-N ratios were higher in sediment-porewaters at 0.16, compared to surface waters (0.010). The calculated EF5-r value (mean = 0.0028; range = 0.0012-0.0069) was up to 3 times greater than the current IPCC EF5-r emissions factor (0.0025 kg N(2)O-N emitted per kg of NO(3)(-)-N leached). The highest EF5-r values were found in the high-flow sampling events when dissolved N(2)O and NO(3)(-) concentrations were low, highlighting potential constraints in the IPCC methodology for large rivers.
Collapse
Affiliation(s)
- Sarra E Hinshaw
- Land, Air and Water Resources, University of California, Davis, One Shields Avenue, Davis, California 95616, United States.
| | | |
Collapse
|
24
|
Schreiber F, Wunderlin P, Udert KM, Wells GF. Nitric oxide and nitrous oxide turnover in natural and engineered microbial communities: biological pathways, chemical reactions, and novel technologies. Front Microbiol 2012; 3:372. [PMID: 23109930 PMCID: PMC3478589 DOI: 10.3389/fmicb.2012.00372] [Citation(s) in RCA: 144] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Accepted: 09/28/2012] [Indexed: 12/20/2022] Open
Abstract
Nitrous oxide (N(2)O) is an environmentally important atmospheric trace gas because it is an effective greenhouse gas and it leads to ozone depletion through photo-chemical nitric oxide (NO) production in the stratosphere. Mitigating its steady increase in atmospheric concentration requires an understanding of the mechanisms that lead to its formation in natural and engineered microbial communities. N(2)O is formed biologically from the oxidation of hydroxylamine (NH(2)OH) or the reduction of nitrite (NO(-) (2)) to NO and further to N(2)O. Our review of the biological pathways for N(2)O production shows that apparently all organisms and pathways known to be involved in the catabolic branch of microbial N-cycle have the potential to catalyze the reduction of NO(-) (2) to NO and the further reduction of NO to N(2)O, while N(2)O formation from NH(2)OH is only performed by ammonia oxidizing bacteria (AOB). In addition to biological pathways, we review important chemical reactions that can lead to NO and N(2)O formation due to the reactivity of NO(-) (2), NH(2)OH, and nitroxyl (HNO). Moreover, biological N(2)O formation is highly dynamic in response to N-imbalance imposed on a system. Thus, understanding NO formation and capturing the dynamics of NO and N(2)O build-up are key to understand mechanisms of N(2)O release. Here, we discuss novel technologies that allow experiments on NO and N(2)O formation at high temporal resolution, namely NO and N(2)O microelectrodes and the dynamic analysis of the isotopic signature of N(2)O with quantum cascade laser absorption spectroscopy (QCLAS). In addition, we introduce other techniques that use the isotopic composition of N(2)O to distinguish production pathways and findings that were made with emerging molecular techniques in complex environments. Finally, we discuss how a combination of the presented tools might help to address important open questions on pathways and controls of nitrogen flow through complex microbial communities that eventually lead to N(2)O build-up.
Collapse
Affiliation(s)
- Frank Schreiber
- Department of Environmental Microbiology, Eawag - Swiss Federal Institute of Aquatic Science and Technology Dübendorf, Switzerland ; Department of Environmental Systems Sciences, Eidgenössische Technische Hochschule Zurich, Switzerland
| | | | | | | |
Collapse
|
25
|
Sasaki Y, Koba K, Yamamoto M, Makabe A, Ueno Y, Nakagawa M, Toyoda S, Yoshida N, Yoh M. Biogeochemistry of nitrous oxide in Lake Kizaki, Japan, elucidated by nitrous oxide isotopomer analysis. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2010jg001589] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
26
|
Townsend-Small A, Pataki DE, Tseng LY, Tsai CY, Rosso D. Nitrous oxide emissions from wastewater treatment and water reclamation plants in southern California. JOURNAL OF ENVIRONMENTAL QUALITY 2011; 40:1542-50. [PMID: 21869516 DOI: 10.2134/jeq2011.0059] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Nitrous oxide (N₂O) is a long-lived and potent greenhouse gas produced during microbial nitrification and denitrification. In developed countries, centralized water reclamation plants often use these processes for N removal before effluent is used for irrigation or discharged to surface water, thus making this treatment a potentially large source of N₂O in urban areas. In the arid but densely populated southwestern United States, water reclamation for irrigation is an important alternative to long-distance water importation. We measured N₂O concentrations and fluxes from several wastewater treatment processes in urban southern California. We found that N removal during water reclamation may lead to in situ N₂O emission rates that are three or more times greater than traditional treatment processes (C oxidation only). In the water reclamation plants tested, N₂O production was a greater percentage of total N removed (1.2%) than traditional treatment processes (C oxidation only) (0.4%). We also measured stable isotope ratios (δN and δO) of emitted N₂O and found distinct δN signatures of N₂O from denitrification (0.0 ± 4.0 ‰) and nitrification reactors (-24.5 ± 2.2 ‰), respectively. These isotope data confirm that both nitrification and denitrification contribute to N₂O emissions within the same treatment plant. Our estimates indicate that N₂O emissions from biological N removal for water reclamation may be several orders of magnitude greater than N₂O emissions from agricultural activities in highly urbanized southern California. Our results suggest that wastewater treatment that includes biological nitrogen removal can significantly increase urban N₂O emissions.
Collapse
|
27
|
Baulch HM, Schiff SL, Thuss SJ, Dillon PJ. Isotopic character of nitrous oxide emitted from streams. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2011; 45:4682-4688. [PMID: 21534582 DOI: 10.1021/es104116a] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Global models have indicated agriculturally impacted rivers and streams may be important sources of the greenhouse gas nitrous oxide (N(2)O). However, there is significant uncertainty in N(2)O budgets. Isotopic characterization can be used to help constrain N(2)O budgets. We present the first published measurements of the isotopic character of N(2)O emitted from low (2-4) order streams. Isotopic character of N(2)O varied seasonally, among streams, and over diel periods. On an annual basis, δ(18)O of emitted N(2)O (+47.4 to +51.4‰; relative to VSMOW) was higher than previously reported for larger rivers, but δ(15)N of emitted N(2)O (-16.2 to +2.4‰ among streams; relative to atmospheric N(2)) was similar to that of past studies. On an annual basis, all streams emitted N(2)O with lower δ(15)N than tropospheric N(2)O. Given these streams have elevated nitrate concentrations which are associated with enhanced N(2)O fluxes, this supports the hypothesis that streams are contributing to the accumulation of (15)N-depleted N(2)O in the troposphere.
Collapse
Affiliation(s)
- Helen M Baulch
- Environmental and Life Sciences Graduate Program, Trent University, 1600 West Bank Drive, Peterborough ON K9J 7B8 Canada.
| | | | | | | |
Collapse
|
28
|
Toyoda S, Suzuki Y, Hattori S, Yamada K, Fujii A, Yoshida N, Kouno R, Murayama K, Shiomi H. Isotopomer analysis of production and consumption mechanisms of N2O and CH4 in an advanced wastewater treatment system. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2011; 45:917-922. [PMID: 21171662 DOI: 10.1021/es102985u] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Wastewater treatment processes are believed to be anthropogenic sources of nitrous oxide (N(2)O) and methane (CH(4)). However, few studies have examined the mechanisms and controlling factors in production of these greenhouse gases in complex bacterial systems. To elucidate production and consumption mechanisms of N(2)O and CH(4) in microbial consortia during wastewater treatment and to characterize human waste sources, we measured their concentrations and isotopomer ratios (elemental isotope ratios and site-specific N isotope ratios in asymmetric molecules of NNO) in water and gas samples collected by an advanced treatment system in Tokyo. Although the estimated emissions of N(2)O and CH(4) from the system were found to be lower than those from the typical treatment systems reported before, water in biological reaction tanks was supersaturated with both gases. The concentration of N(2)O, produced mainly by nitrifier-denitrification as indicated by isotopomer ratios, was highest in the oxic tank (ca. 4000% saturation). The dissolved CH(4) concentration was highest in in-flow water (ca. 3000% saturation). It decreased gradually during treatment. Its carbon isotope ratio indicated that the decrease resulted from bacterial CH(4) oxidation and that microbial CH(4) production can occur in anaerobic and settling tanks.
Collapse
Affiliation(s)
- Sakae Toyoda
- Department of Environmental Chemistry and Engineering, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8502, Japan.
| | | | | | | | | | | | | | | | | |
Collapse
|
29
|
Beaulieu JJ, Shuster WD, Rebholz JA. Nitrous oxide emissions from a large, impounded river: the Ohio River. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2010; 44:7527-33. [PMID: 20804185 DOI: 10.1021/es1016735] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Models suggest that microbial activity in streams and rivers is a globally significant source of anthropogenic nitrous oxide (N(2)O), a potent greenhouse gas, and the leading cause of stratospheric ozone destruction. However, model estimates of N(2)O emissions are poorly constrained due to a lack of direct measurements of microbial N(2)O production and consequent emissions, particularly from large rivers. We report the first N(2)O budget for a large, nitrogen enriched river, based on direct measurements of N(2)O emissions from the water surface and N(2)O production in the sediments and water column. Maximum N(2)O emissions occurred downstream from Cincinnati, Ohio, a major urban center on the river, due to direct inputs of N(2)O from wastewater treatment plant effluent and higher rates of in situ production. Microbial activity in the water column and sediments was a source of N(2)O, and water column production rates were nearly double those of the sediments. Emissions exhibited strong seasonality with the highest rates observed during the summer and lowest during the winter. Our results indicate N(2)O dynamics in large temperate rivers may be characterized by strong seasonal cycles and production in the pelagic zone.
Collapse
Affiliation(s)
- J J Beaulieu
- National Risk Management Research Laboratory, Office of Research and Development, US Environmental Protection Agency, 26 West Martin Luther King Drive, Cincinnati, Ohio 45268, USA.
| | | | | |
Collapse
|
30
|
Tobari Y, Koba K, Fukushima K, Tokuchi N, Ohte N, Tateno R, Toyoda S, Yoshioka T, Yoshida N. Contribution of atmospheric nitrate to stream-water nitrate in Japanese coniferous forests revealed by the oxygen isotope ratio of nitrate. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2010; 24:1281-1286. [PMID: 20391599 DOI: 10.1002/rcm.4498] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Evaluation of the openness of the nitrogen (N) cycle in forest ecosystems is important in efforts to improve forest management because the N supply often limits primary production. The use of the oxygen isotope ratio (delta(18)O) of nitrate is a promising approach to determine how effectively atmospheric nitrate can be retained in a forest ecosystem. We investigated the delta(18)O of nitrate in stream water in order to estimate the contribution of atmospheric NO(3) (-) in stream-water NO(3) (-) (f(atm)) from 26 watersheds with different stand ages (1-87 years) in Japan. The stream-water nitrate concentrations were high in young forests whereas, in contrast, old forests discharged low-nitrate stream water. These results implied a low f(atm) and a closed N cycle in older forests. However, the delta(18)O values of nitrate in stream water revealed that f(atm) values were higher in older forests than in younger forests. These results indicated that even in old forests, where the discharged N loss was small, atmospheric nitrate was not retained effectively. The steep slopes of the studied watersheds (>40 degrees ) which hinder the capturing of atmospheric nitrate by plants and microbes might be responsible for the inefficient utilization of atmospheric nitrate. Moreover, the unprocessed fraction of atmospheric nitrate in the stream-water nitrate in the forest (f(unprocessed)) was high in the young forest (78%), although f(unprocessed) was stable and low for other forests (5-13%). This high f(unprocessed) of the young forest indicated that the young forest retained neither atmospheric NO(3) (-) nor soil NO(3) (-) effectively, engendering high stream-water NO(3) (-) concentrations.
Collapse
Affiliation(s)
- Y Tobari
- Department of Environmental Science and Technology, Tokyo Institute of Technology, 2268501, Yokohama, Japan
| | | | | | | | | | | | | | | | | |
Collapse
|