DOI: 10.1016/j.watres.2018.06.004
Scopus记录号: 2-s2.0-85048525458
论文题名: Nitrogen sources and cycling revealed by dual isotopes of nitrate in a complex urbanized environment
作者: Archana A. ; Thibodeau B. ; Geeraert N. ; Xu M.N. ; Kao S.-J. ; Baker D.M.
刊名: Water Research
ISSN: 431354
出版年: 2018
卷: 142 起始页码: 459
结束页码: 470
语种: 英语
英文关键词: Anthropogenic
; Eutrophication
; Fractionation
; Isotopes
; Mixing
; Nitrate
Scopus关键词: Ecosystems
; Effluents
; Eutrophication
; Fractionation
; Groundwater
; Isotopes
; Meteorological problems
; Mixing
; Nitrates
; Nitrogen
; Nutrients
; Quality management
; River pollution
; Sewage
; Water conservation
; Water management
; Water quality
; Anthropogenic
; Atmospheric depositions
; Coastal marine ecosystems
; Groundwater nitrates
; Nutrient concentrations
; Relative contribution
; Transformation process
; Water quality monitoring
; Nitrogen fixation
; fresh water
; ground water
; isotope
; nitrate
; nitrogen
; nitrogen 15
; oxygen 18
; river water
; sea water
; anthropogenic source
; atmospheric deposition
; denitrification
; eutrophication
; marine environment
; nitrate
; nitrification
; nitrogen isotope
; nutrient dynamics
; stable isotope
; transformation
; water quality
; Article
; atmospheric deposition
; China
; denitrification
; effluent
; estuary
; eutrophication
; Hong Kong
; marine environment
; nitrification
; nitrogen cycling
; nutrient concentration
; priority journal
; river
; salinity
; sea
; sewage
; urban area
; China
; Guangdong
; Pacific Ocean
; South China Sea
; Zhujiang Estuary
英文摘要: Elevated nutrient inputs have led to increased eutrophication in coastal marine ecosystems worldwide. An understanding of the relative contribution of different nutrient sources is imperative for effective water quality management. Stable isotope values of nitrate (δ15NNO3-, δ18ONO3-) can complement conventional water quality monitoring programs to help differentiate natural sources of NO3− from anthropogenic inputs and estimate the processes involved in N cycling within an ecosystem. We measured nutrient concentrations, δ15NNO3-, and δ18ONO3- in 76 locations along a salinity gradient from the lower end of the Pearl River Estuary, one of China's largest rivers discharging into the South China Sea, towards the open ocean. NO3− concentrations decreased with increasing salinity, indicative of conservative mixing of eutrophic freshwater and oligotrophic seawater. However, our data did not follow conservative mixing patterns. At salinities <20 psu, samples exhibited decreasing NO3−concentrations with almost unchanged NO3− isotope values, indicating simple dilution. At salinities >20 psu, NO3− concentrations decreased, while dual NO3− isotopes increased, suggesting mixing and/or other transformation processes. Our analysis yielded mean estimates for isotope enrichment factors (15ε = −2.02‰ and 18ε = −3.37‰), Δ(15,18) = -5.5‰ and δ15NNO3- - δ15NNO2- = 12.3‰. After consideration of potential alternative sources (sewage, atmospheric deposition and groundwater) we concluded that there are three plausible interpretations for deviations from conservative mixing behaviour (1) NO3− uptake by assimilation (2) in situ NO3− production (from fixation-derived nitrogen and nitrification of sewage-derived effluents) and (3) input of groundwater nitrate carrying a denitrification signal. Through this study, we propose a simple workflow that incorporates a synthesis of numerous isotope-based studies to constrain sources and behaviour of NO3− in urbanized marine environments. © 2018 Elsevier Ltd Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/112644
Appears in Collections: 气候减缓与适应
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作者单位: School of Biological Sciences, University of Hong Kong, Pok Fu Lam, Hong Kong; Swire Institute of Marine Science, University of Hong Kong, Cape D'Aguilar, Hong Kong; Department of Earth Sciences, University of Hong Kong, Pok Fu Lam, Hong Kong; State Key Laboratory of Marine Environmental Science, Xiamen University, China
Recommended Citation:
Archana A.,Thibodeau B.,Geeraert N.,et al. Nitrogen sources and cycling revealed by dual isotopes of nitrate in a complex urbanized environment[J]. Water Research,2018-01-01,142