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Journal of Integrative Agriculture  2026, Vol. 25 Issue (6): 2580-2594    DOI: 10.1016/j.jia.2026.01.010
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Parallel denitrification and nitrite oxidation in the unsaturated zone: Isotopic constraints from nitrate δ15N and δ18O in Tianjin, China

Dongmei Xue1*, Jinglei Wang1*, Lanxin Xiang1, Xiaoxian Peng1, Ke Jin2#, Yunting Fang3#, Xiangzhen Li4, Yidong Wang1, Zhongliang Wang5

1 Tianjin Key Laboratory of Water Resources and Environment, Tianjin Normal University, Tianjin 300387, China

2 Institute of Grassland Research, Chinese Academy of Agricultural Sciences, Huhhot 010010, China

3 Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China

4 College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou 350002, China

5 Tianjin Key Laboratory of Aquatic Science and Technology, Tianjin Chengjian University, Tianjin 300384, China

 Highlights 

Nitrate reduction drives isotope trajectory variation.

Carbon properties regulate N functional gene expression. 

The Δδ18O:Δδ15N trajectory is effective for assessing denitrification performance.

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摘要  

反硝化作用缓解生态系统人为硝酸盐(NO3-)累积的关键过程,而NO3- 同位素组成(δ¹⁵N  δ¹⁸O)是识别氮来源与转化过程的有效示踪手段。反硝化过程常叠加亚硝酸盐(NO2-)氧化产生的同位素效应,导致δ15N-NO₃⁻δ18O-NO₃⁻同步富集,形成低于或高于1Δδ¹⁸O:Δδ¹⁵N轨迹。本研究以非饱和带为研究对象,比较了Δδ¹⁸O:Δδ¹⁵N轨迹低于或高于1两组条件下,反硝化过程中的Δδ¹⁸O:Δδ¹⁵N轨迹变化、功能基因(narGnapAnxrA)及代谢碳源特征。结果表明,NO3- 还原是导致Δδ¹⁸O:Δδ¹⁵N轨迹变异的主要因素,两组轨迹间NO3- 还原同位素效应(15εNO3 reduction15εNO3 reduction)差异显著,而NO2- 氧化过程的同位素效应(15εnxr 和 18εnxr)无显著差异。在Δδ¹⁸O:Δδ¹⁵N轨迹低于1的组别中,碳源因其低分子量与简单结构,有助于更高效的电子产率,从而促进NO3- 还原;相反,在轨迹高于1的组别中,碳源的高分子量与复杂结构导致电子产率降低,进而下调三个功能基因(narGnapAnxrA)的表达。轨迹低于1的组别在15εNO3 reduction15εNO3 reduction、亚硝酸盐氧化比例以及narGnapAnxrA基因拷贝数方面均显著高于另一组,表明该组在细胞水平的NO3- 还原活性更强。本研究系统阐明了同位素效应、NO3- 还原酶与NO2- 氧化还原酶活性以及代谢碳源对反硝化过程的综合影响。该发现对理解陆地生态系统氮循环中Δδ¹⁸O:Δδ¹⁵N轨迹的形成机制具有重要意义,并为通过优化碳源添加策略以强化反硝化、实现地下水保护提供了理论依据,同时证明Δδ¹⁸O:Δδ¹⁵N轨迹可作为评估陆地环境反硝化效能的有效示踪指标。



Abstract  

Denitrification plays a critical role in mitigating anthropogenic nitrate (NO3) accumulation in ecosystems.  The isotopic composition of NO3 (δ15N and δ18O) serves as a powerful tracer for identifying N sources and transformation processes.  Denitrification often superimposed on the isotope effects of NO2 oxidation, resulting in parallel enrichment of δ15N- and δ18O-NO3(Δδ18O:Δδ15N trajectory) that causes them to be either below or above 1.  This study compared the Δδ18O:Δδ15N trajectory during denitrification, functional genes (narG, napA, and nxrA), and carbon sources from metabolites in the Δδ18O:Δδ15N trajectories below or above 1 in unsaturated zones.  The results revealed that NO3 reduction was more important for variation in the Δδ18O:Δδ15N trajectory because the difference in isotope effects (15εNO3 reduction and 18εNO3 reduction) between the two Δδ18O:Δδ15N trajectory groups was significant, whereas the difference in isotope effects (15εnxr and 18εnxr) upon NO2 oxidation was not.  Carbon sources in the group with Δδ18O:Δδ15N trajectories below 1 facilitated more efficient electron production to promote NO3 reduction because of their low molecular weight and simple structure.  Conversely, the lower electron production efficiency due to the high molecular weight and complex structures of carbon sources in the group with Δδ18O:Δδ15N trajectories above 1 downregulated the expression of the three functional genes (narG, napA, and nxrA).  The group with Δδ18O:Δδ15N trajectories below 1 showed significantly higher levels of 15εNO3 reduction, 18εNO3 reduction, NO2 oxidation ratio, and copy numbers of narG, napA, and nxrA genes compared to the other group, revealing that NO3reduction at the cellular level was more active in the former group.  This study elucidated the integrated influence of isotope effects, NO3 reductase and NO2oxidoreductase activities, and carbon sources from metabolites.  These findings are significant for understanding the Δδ18O:Δδ15N trajectories of N cycling in terrestrial ecosystems and support groundwater conservation by improving carbon supplementation approaches that stimulate denitrification, with Δδ18O:Δδ15N trajectories serving as effective tracers for assessing denitrification performance in terrestrial environments.

Keywords:  denitrification       NO2 oxidation       Δδ18O:Δδ15N trajectory       NO3 reductase       NO2 oxidoreductase       carbon sources  
Received: 05 May 2025   Accepted: 27 October 2025 Online: 13 January 2026  
Fund: 

This work was financially supported by the National Natural Science Foundation of China (42361144860, 41973017 and 32071861).

About author:  Dongmei Xue, E-mail: xuedongmei@tjnu.edu.cn; Jinglei Wang, E-mail: 17861007620@163.com; #Correspondence Ke Jin, E-mail: jinke@caas.cn; Yunting Fang, E-mail: fangyt@iae.ac.cn * These authors contributed equally to this study.

Cite this article: 

Dongmei Xue, Jinglei Wang, Lanxin Xiang, Xiaoxian Peng, Ke Jin, Yunting Fang, Xiangzhen Li, Yidong Wang, Zhongliang Wang. 2026. Parallel denitrification and nitrite oxidation in the unsaturated zone: Isotopic constraints from nitrate δ15N and δ18O in Tianjin, China. Journal of Integrative Agriculture, 25(6): 2580-2594.

Arshad A, Speth D R, De Graaf R M, Op den Camp H J, Jetten M S, Welte C U. 2015. A metagenomics-based metabolic model of nitrate-dependent anaerobic oxidation of methane by Methanoperedens-like archaea. Frontiers in Microbiology6, 1423.

Asamoto C K, Rempfert K R, Luu V H, Younkin A D, Kopf S H. 2021. Enzyme-specific coupling of oxygen and nitrogen isotope fractionation of the Nap and Nar nitrate reductases. Environmental Science & Technology55, 5537–5546.

Bao Y F, Sun M, Wang Y C, Hu M M, Hu P, Wu L X, Huang W, Li S Z, Wen J, Wang Z J. 2024. Nitrate transformation and source tracking of Yarlung Tsangpo River using a multi-tracer approach combined with Bayesian stable isotope mixing model. Environmental Research252, 118925.

Bollag J M, Kaiser J P. 1991. The transformation of heterocyclic aromatic compounds and their derivatives under anaerobic conditions. Critical Reviews in Environmental Science Technology21, 297–329.

Böttcher J, Strebel O, Voerkelius S, Schmidt H L. 1990. Using isotope fractionation of nitrate-nitrogen and nitrate-oxygen for evaluation of microbial denitrification in a sandy aquifer. Journal of Hydrology114, 413–424.

Brandes J A, Devol A H. 1997. Isotopic fractionation of oxygen and nitrogen in coastal marine sediments. Geochimica et Cosmochimica Acta61, 1793–1801.

Brozinčević A, Grgas D, Štefanac T, Habuda-Stanić M, Zelić B, Landeka Dragičević T. 2024. Cost reduction in the process of biological denitrification by choosing traditional or alternative carbon sources. Energies17, 3660.

Brunner B, Contreras S, Lehmann M F, Matantseva O, Rollog M, Kalvelage T, Klockgether G, Lavik G, Jetten M S, Kartal B, Kuypers M M M. 2013. Nitrogen isotope effects induced by anammox bacteria. Proceedings of the National Academy of Sciences of the United States of America110, 18994–18999.

Buchwald C, Casciotti K L. 2010. Oxygen isotopic fractionation and exchange during bacterial nitrite oxidation. Limnology and Oceanography55, 1064–1074.

Buchwald C, Casciotti K L. 2013. Isotopic ratios of nitrite as tracers of the sources and age of oceanic nitrite. Nature Geoscience6, 308–313.

Buchwald C, Santoro A E, Stanley R H R, Casciotti K L. 2015. Nitrogen cycling in the secondary nitrite maximum of the eastern tropical North Pacific off Costa Rica. Global Biogeochemical Cycles29, 2061–2081.

Buchwald C, Wankel S D. 2022. Enzyme-catalyzed isotope equilibrium: A hypothesis to explain apparent N cycling phenomena in low oxygen environments. Marine Chemistry244, 104–140.

Casciotti K L. 2009. Inverse kinetic isotope fractionation during bacterial nitrite oxidation. Geochimica et Cosmochimica Acta73, 2061–2076.

Casciotti K L. 2016. Nitrogen and oxygen isotopic studies of the marine nitrogen cycle. Annual Review of Marine Science8, 379–407.

Casciotti K L, Buchwald C, Mcilvin M. 2013. Implications of nitrate and nitrite isotopic measurements for the mechanisms of nitrogen cycling in the Peru oxygen deficient zone. Deep Sea Research
(Part I: Oceanographic Research Papers), 80, 78–93.

Casciotti K L, Sigman D M, Hastings M G, Böhlke J K, Hilkert A. 2002. Measurement of the oxygen isotopic composition of nitrate in seawater and freshwater using the denitrifier method. Analytical Chemistry74, 4905–4912.

Cech J S, Hartman P, Slosárek M, Chudoba J. 1988. Isolation and identification of a morpholine-degrading bacterium. Applied & Environmental Microbiology54, 619–621.

Chayabutra C, Wu J, Ju L K. 2001. Rhamnolipid production by Pseudomonas aeruginosa under denitrification: Effects of limiting nutrients and carbon substrates. Biotechnology and Bioengineering72, 25–33.

Chen X T, Zhao B H, Zhang J, Li Y Q, Yang H S, Zhang Y Q. 2023. Rapid start-up of partial nitrification reactor by exogenous AHLs and Vanillin combined with intermittent aeration. Science of the Total Environment859, 160191.

Chicano T M, Dietrich L, Almeida N M D, Akram M, Barends T R M. 2021. Structural and functional characterization of the intracellular filament-forming nitrite oxidoreductase multiprotein complex. Nature Microbiology6, 1129–1139.

Coelho C, Romao M J. 2015. Structural and mechanistic insights on nitrate reductases. Protein Science24, 1901–1911.

Daims H, Lebedeva E V, Pjevac P, Han P, Herbold C, Albertsen M, Jehmlich N, Palatinszky M, Vierheilig J, Bulaev A. 2015. Complete nitrification by Nitrospira bacteria. Nature528, 504–509.

Denk T R, Mohn J, Decock C, Lewicka-Szczebak D, Harris E, Butterbach-Bahl K, Kiese R, Wolf B. 2017. The nitrogen cycle: A review of isotope effects and isotope modeling approaches. Soil Biology and Biochemistry105, 121–137.

Elefsiniotis P, Wareham D G, Smith M O. 2004. Use of volatile fatty acids from an acid-phase digester for denitrification. Journal of Biotechnology114, 289–297.

Fang Y T, Koba K, Makabe A, Takahashi C, Zhu W X, Hayashi T, Hokari A A, Urakawa R, Bai E, Houlton B Z, Xi D, Zhang S S, Matsushita K, Tu Y, Liu D W, Zhu F F, Wang Z Y, Zhou G Y, Chen D X, Makita T, et al. 2015. Microbial denitrification dominates nitrate losses from forest ecosystems. Proceedings of the National Academy of Sciences of the United States of America112, 1470–1474.

Frey C, Hietanen S, Jürgens K, Labrenz M, Voss M. 2014. N and O isotope fractionation in nitrate during chemolithoautotrophic denitrification by Sulfurimonas gotlandicaEnvironmental Science & Technology48, 13229–13237.

Füssel J, Lam P, Lavik G, Jensen M M, Holtappels M, Günter M, Kuypers M M M. 2012. Nitrite oxidation in the Namibian oxygen minimum zone. ISME Journal6, 1200–1209.

Gao S H, Fan L, Peng L, Guo J H, Agulló-Barceló M, Yuan Z G, Bond P L. 2016. Determining multiple responses of Pseudomonas aeruginosa PAO1 to an antimicrobial agent, free nitrous acid. Environmental Science & Technology50, 5305–5312.

Ge S J, Peng Y Z, Wang S Y, Lu C C, Cao X, Zhu Y P. 2012. Nitrite accumulation under constant temperature in anoxic denitrification process: The effects of carbon sources and COD/NO3-N. Bioresource Technology114, 137–143.

González P J, Correia C, Moura I, Brondino C D, Moura J J G. 2006. Bacterial nitrate reductases: Molecular and biological aspects of nitrate reduction. Journal of Inorganic Biochemistry100, 1015–1023.

Van de Graaf A A, Mulder A, De Bruijn P, Jetten M, Robertson L A, Kuenen J G. 1995. Anaerobic oxidation of ammonium is a biologically mediated process. Applied and Environmental Microbiology61, 1246–1251.

Granger J, Sigman D M. 2009. Removal of nitrite with sulfamic acid for nitrate N and O isotope analysis with the denitrifier method. Rapid Communications in Mass Spectrometry23, 3753–3762.

Granger J, Sigman D M, Lehmann M F, Tortell P D. 2008. Nitrogen and oxygen isotope fractionation during dissimilatory nitrate reduction by denitrifying bacteria. Limnology and Oceanography53, 2533–2545.

Granger J, Sigman D M, Rohde M M, Maldonado M T, Tortell P D. 2010. N and O isotope effects during nitrate assimilation by unicellular prokaryotic and eukaryotic plankton cultures. Geochimica et Cosmochimica Acta74, 1030–1040.

Granger J, Wankel S D. 2016. Isotopic overprinting of nitrification on denitrification as a ubiquitous and unifying feature of environmental nitrogen cycling. Proceedings of the National Academy of Sciences of the United States of America113, E6391–E6400.

Gregory G, Boyd E F. 2021. Stressed out: Bacterial response to high salinity using compatible solute biosynthesis and uptake systems, lessons from VibrionaceaeComputational and Structural Biotechnology Journal19, 1014–1027.

Gruber N, Galloway J N. 2008. An Earth-system perspective of the global nitrogen cycle. Nature451, 293–296.

Harms N C, Lahajnar N, Gaye B, Rixen T, Dähnke K, Ankele M, Schwarz-Schampera U, Emeis K C. 2019. Nutrient distribution and nitrogen and oxygen isotopic composition of nitrate in water masses of the subtropical southern Indian Ocean. Biogeosciences16, 2715–2732.

Hu X J, Gu H D, Liu J J, Wei D, Zhu P, Cui X A, Zhou B K, Chen X L, Jin J, Liu X B, Wang G H. 2022. Metagenomics reveals divergent functional profiles of soil carbon and nitrogen cycling under long-term addition of chemical and organic fertilizers in the black soil region. Geoderma418, 115846.

Jetten M S, Niftrik Lv, Strous M, Kartal B, Keltjens J T, Op den Camp H J. 2009. Biochemistry and molecular biology of anammox bacteria. Critical Reviews in Biochemistry and Molecular Biology44, 65–84.

Jiang L, Tang Y X, Sun W H, Yi N, Zhang Y M, Shi H C, Rittmann B E. 2017. Simultaneous di-oxygenation and denitrification in an internal circulation baffled bioreactor. Biodegradation28, 195–203.

Karsh K L, Granger J, Kritee K, Sigman D M. 2012. Eukaryotic assimilatory nitrate reductase fractionates N and O isotopes with a ratio near unity. Environmental Science & Technology46, 5727–5735.

Kemeny P C, Weigand M, Zhang R, Carter B, Karsh K, Fawcett S, Sigman D M. 2016. Enzyme-level interconversion of nitrate and nitrite in the fall mixed layer of the Antarctic Ocean. Global Biogeochemical Cycles30, 1069–1085.

Kobayashi K, Makabe A, Yano M, Oshiki M, Kindaichi T, Casciotti K L, Okabe S. 2019. Dual nitrogen and oxygen isotope fractionation during anaerobic ammonium oxidation by anammox bacteria. ISME Journal13, 2426–2436.

Kraft B, Strous M, Tegetmeyer H E. 2011. Microbial nitrate respiration - Genes, enzymes and environmental distribution. Journal of Biotechnology155, 104–117.

Kritee K, Sigman D M, Granger J, Ward B B, Jayakumar A, Deutsch C. 2012. Reduced isotope fractionation by denitrification under conditions relevant to the ocean. Geochimica et Cosmochimica Acta92, 243–259.

Lam P, Kuypers M M. 2011. Microbial nitrogen cycling processes in oxygen minimum zones. Annual Review of Marine Science3, 317–345.

Lehman M F, Sigman D M, Berelson W M. 2004. Coupling the 15N/14N and 18O/16O of nitrate as a constraint on benthic nitrogen cycling. Marine Chemistry88, 1–20.

Leng X Y, Xue D M, Wang Y D, Wang Z L. 2023. Spatial difference of organic composition in farmland soil profile between sea immersion area and non-sea immersion area in Tianjin. Journal of Tianjin Normal Unierisity (Natural Science Edition), 43, 30–37. (in Chinese)

Lipschultz F, Wofsy S C, Ward B B, Codispoti L A, Friedrich G, Elkins J W. 1990. Bacterial transformations of inorganic nitrogen in the oxygen-deficient waters of the Eastern Tropical South Pacific Ocean. Deep Sea Research (Part A: Oceanographic Research Papers), 37, 1513–1541.

Liu W, Huo R, Xu J X, Liang S X, Li J J, Zhao T K, Wang S T. 2017. Effects of biochar on nitrogen transformation and heavy metals in sludge composting. Bioresource Technology235, 43–49.

Lu Y C, Li D X, Li C Q, Sun M Y, Wu Z J, Sun Z M. 2022. The effects of 3, 5-dimethylpyrazole on soil nitrification and related enzyme activities in brown soil. Agronomy Journal12, 1425.

Lycus P, Einsle O, Zhang L. 2023. Structural biology of proteins involved in nitrogen cycling. Current Opinion in Chemical Biology74, 102278.

Mekala L P, Mohammed M, Chinthalapati S, Chinthalapat V. R. 2019. Pyomelanin production: Insights into the incomplete aerobic l-phenylalanine catabolism of a photosynthetic bacterium, Rubrivivax benzoatilyticus JA2. International Journal of Biological Macromolecules126, 755–764.

Moran M A, Kujawinski E B, Schroer W F, Amin S A, Bates N R, Bertrand E M, Braakman R, Brown C T, Covert M W, Doney S C, Dyhrman S T, Edison A S, Eren A M, Levine N M, Li L, Ross A C, Saito M A, Santoro A E, Segrè D, Shade A, et al. 2022. Microbial metabolites in the marine carbon cycle. Nature Microbiology7, 508–523.

Pandey C B, Kumar U, Kaviraj M, Minick K J, Mishra A K, Singh J S. 2020. DNRA: A short-circuit in biological N-cycling to conserve nitrogen in terrestrial ecosystems. Science of the Total Environment738, 139710.

Pang Y M, Wang J L. 2021. Various electron donors for biological nitrate removal: A review. Science of the Total Environment794, 148699.

Paredes I, Otero N, Soler A, Green A J, Soto D X. 2020. Agricultural and urban delivered nitrate pollution input to Mediterranean temporary freshwaters. AgricultureEcosystems & Environment294, 106859.

Pinchbeck B J, Soriano-Laguna M J, Sullivan M J, Luque-Almagro V M, Rowley G, Ferguson S J, Roldan M D, Richardson D J, Gates A J. 2019. A dual functional redox enzyme maturation protein for respiratory and assimilatory nitrate reductases in bacteria. Molecular Microbiology111, 1592–1603.

Qi S S, Lin J B, Wang Y L, Yuan S J, Wang W, Xiao L W, Zhan X M, Hu Z H. 2021. Fermentation liquid production of food wastes as carbon source for denitrification: Laboratory and full-scale investigation. Chemosphere270, 129460.

Rho E, Evans W. 1975. The aerobic metabolism of cyclohexanecarboxylic acid by Acinetobacter anitratumBiochemical Journal148, 11–15.

Richardson D J, Berks B C, Russell D A, Spiro S, Taylor C J. 2001. Functional, biochemical and genetic diversity of prokaryotic nitrate reductases. Cellular and Molecular Life Sciences58, 165–178.

Ruan X Y, Yin J, Cui X Y, Li N, Shen D S. 2020. Bioaugmentation and quorum sensing disruption as solutions to increase nitrate removal in sequencing batch reactors treating nitrate-rich wastewater. Journal of Environmental Sciences98, 179–185.

Schneider S, Mohamed M E S, Fuchs G. 1997. Anaerobic metabolism of L-phenylalanine via benzoyl-CoA in the denitrifying bacterium Thauera aromaticaArchives of Microbiology168, 310–320.

Sigman D M, Casciotti K L, Andreani M, Barford C, Galanter M, Böhlke J. 2001. A bacterial method for the nitrogen isotopic analysis of nitrate in seawater and freshwater. Analytical Chemistry73, 4145–4153.

Sigman D M, Granger J, Difiore P J, Lehmann M M, Ho R, Cane G, Geen A V. 2006. Coupled nitrogen and oxygen isotope measurements of nitrate along the eastern North Pacific margin. Global Biogeochemical Cycles20, GB100.

Singh S, Anil A G, Kumar V, Kapoor D, Subramanian S, Singh J, Ramamurthy P C. 2022. Nitrates in the environment: A critical review of their distribution, sensing techniques, ecological effects and remediation. Chemosphere287, 131996.

Sparacino-Watkins C, Stolz J F, Basu P. 2014. Nitrate and periplasmic nitrate reductases. Chemical Society Reviews43, 676–706.

Strous M, Kuenen J G, Jetten M S. 1999. Key physiology of anaerobic ammonium oxidation. Applied and Environmental Microbiology65, 3248–3250.

Su X X, Wang Y Y, He Q, Hu X B, Chen Y. 2019. Biochar remediates denitrification process and N2O emission in pesticide chlorothalonil-polluted soil: role of electron transport chain. Chemical Engineering Journal370, 587–594.

Sun X, Ji Q X, Jayakumar A, Ward B B. 2017. Dependence of nitrite oxidation on nitrite and oxygen in low oxygen seawater. Geophysical Research Letters44, 7883–7891.

Tan Q Y, Zhang G Y, Ding A Z, Bian Z Y, Wang X, Xing Y Z, Zheng L. 2023. Anthropogenic land-use activities within watersheds reduce comammox activity and diversity in rivers. Journal of Environmental Management338, 117841.

Tomei M C, Annesini M C. 2005. 4-Nitrophenol biodegradation in a sequencing batch reactor operating with aerobic-anoxic cycles. Environmental Science & Technology39, 5059–5065.

Treibergs L A, Granger J. 2017. Enzyme level N and O isotope effects of assimilatory and dissimilatory nitrate reduction. Limnology and Oceanography62, 272–288.

Vadivelu V M, Yuan Z, Fux C, Keller J. 2006. The inhibitory effects of free nitrous acid on the energy generation and growth processes of an enriched Nitrobacter culture. Environmental Science & Technology40, 4442–4448.

Valiente N, Gil-Márquez J M, Gómez-Alday J J, Andreo B. 2020. Unraveling groundwater functioning and nitrate attenuation in evaporitic karst systems from southern Spain: An isotopic approach. Applied Geochemistry123, 104820.

Wang A, Fang Y T, Chen D X, Phillips O, Koba K, Zhu W X, Zhu J J. 2018. High nitrogen isotope fractionation of nitrate during denitrification in four forest soils and its implications for denitrification rate estimates. Science of the Total Environment633, 1078–1088.

Wang H, Zhang J Q, Zhang Y F, Li J F, Li F L, Strydonck M V, Hendrix V. 2000. Chronology of the Chenier I and shoreline changes since the last 1ka, on western coast of Bohai Bay. Marine Geology & Quat Ernary Geology20, 7–14. (in Chinese)

Wang L, Li Y M, Ma N, Gu G W. 2009. Effects of pyridine and methanol on the biodegradation of 2-methylpyridine by activated sludge under denitrifying conditions. In: International Conference on Energy and Environment Technology. IEEE, Guilin, China. pp. 618–621.

Wang Q, Garrity G M, Tiedje J M, Cole J R. 2007. Naive Bayesian classifier for rapid assignment of rRNA sequences into the new bacterial taxonomy. Applied and Environmental Microbiology73, 5261–5267.

Wang S Y, Radny D, Huang S B, Zhuang L J, Zhao S Y, Berg M, Jetten M S, Zhu G B. 2017. Nitrogen loss by anaerobic ammonium oxidation in unconfined aquifer soils. Scientific Reports7, 40173.

Wang Z F, Zhang Y J, Li X, Li J K, Zhao Z M, Hou X. 2023. Mixed culture of plants improved nutrient removal in constructed wetlands: Response of microbes and root exudates. Environmental Science and Pollution Research30, 5861–5872.

Wei Q, Zhang J S, Luo F Z, Shi D H, Liu Y C, Liu S, Zhang Q, Sun W Z, Yuan J L, Fan H T. 2022. Molecular mechanisms through which different carbon sources affect denitrification by Thauera linaloolentis: Electron generation, transfer, and competition. Environment International170, 107598.

Welte C U, Rasigraf O, Vaksmaa A, Versantvoort W, Arshad A, Op den Camp H J, Jetten M S, Lüke C, Reimann J. 2016. Nitrate- and nitrite-dependent anaerobic oxidation of methane. Environmental Microbiology Reports8, 941–955.

Wenk C B, Zopfi J, Blees J, Veronesi M, Niemann H, Lehmann M F. 2014. Community N and O isotope fractionation by sulfide-dependent denitrification and anammox in a stratified lacustrine water column. Geochimica et Cosmochimica Acta125, 551–563.

Wunderlich A, Meckenstock R, Einsiedl F. 2012. Effect of different carbon substrates on nitrate stable isotope fractionation during microbial denitrification. Environmental Science & Technology46, 4861–4868.

Wunderlich A, Meckenstock R U, Einsiedl F. 2013. A mixture of nitrite-oxidizing and denitrifying microorganisms affects the δ18O of dissolved nitrate during anaerobic microbial denitrification depending on the δ18O of ambient water. Geochimica et Cosmochimica Acta119, 31–45.

Xue D M, Baets B D, Vermeulen J, Botte J, Cleemput O V, Boeckx P. 2010. Error assessment of nitrogen and oxygen isotope ratios of nitrate as determined via the bacterial denitrification method. Rapid Communications in Mass Spectrometry24, 1979–1984.

Xue D M, Botte J, Baets B D, Accoe F, Nestler A, Taylor P, Cleemput O V, Berglund M, Boeckx P. 2009. Present limitations and future prospects of stable isotope methods for nitrate source identification in surface- and groundwater. Water Research43, 1159–1170.

Xue D M, Yu H, Fang Y T, Shan J, Xi D, Wang Y D, Kuzyakov Y, Wang Z L. 2020. 15N-tracer approach to assess nitrogen cycling processes: Nitrate reduction, anammox and denitrification in different pH cropland soils. Catena193, 104611.

Yue F J, Liu X L, Li J, Zhu Z Z, Wang Z L. 2010. Using nitrogen isotopic approach to identify nitrate sources in waters of Tianjin, China. Bulletin of Environmental Contamination and Toxicology85, 562–567.

Zhan M J, Zeng W, Wu C C, Chen G X, Meng Q A, Hao X J, Peng Y Z. 2024. Impact of organic carbon on sulfide-driven autotrophic denitrification: Insights from isotope fractionation and functional genes. Water Research255, 121507.

Zhang D D, Li M Y, Yang Y C, Yu H, Xiao F S, Mao C Z, Huang J, Yu Y H, Wang Y F, Wu B, Wang C, Shu L F, He Z L, Yan Q Y. 2022. Nitrite and nitrate reduction drive sediment microbial nitrogen cycling in a eutrophic lake. Water Research220, 118637.

Zhao J F, Yang J Q, Xie H F, Qin X, Huang R X. 2024. Sustainable management strategies for balancing crop yield, water use efficiency and greenhouse gas emissions. Agricultural Systems217, 103944.

Zheng W B, Wang S Q, Tan K D, Lei Y P. 2020. Nitrate accumulation and leaching potential is controlled by land-use and extreme precipitation in a headwater catchment in the North China Plain. Science of the Total Environment707, 136168.

Zhou Y, Oehmen A, Lim M, Vadivelu V, Ng W J. 2011. The role of nitrite and free nitrous acid (FNA) in wastewater treatment plants. Water Research, 45, 4672–4682.

Zhu Q, Liang Y F, Zhang Q, Zhang Z Y, Wang C P, Zhai S, Li Y H, Sun H W. 2023. Biochar derived from hydrolysis of sewage sludge influences soil properties and heavy metals distributed in the soil. Journal of Hazardous Materials442, 130053.

Zhu Y S, Wang Y D, Guo C C, Xue D M, Li J, Chen Q, Song Z L, Lou Y L, Kuzyakov Y, Wang Z L. 2020. Conversion of coastal mars4hes to croplands decreases organic carbon but increases inorganic carbon in saline soils. Land Degradation & Development31, 1099–1109.

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