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Zhang X, Mahmoud SH, Wang H, Gao L, Langford M, Zhang W. Predicting stormwater nitrogen loads from a cold-region urban catchment in year 2050 under the impacts of climate change and urban densification. WATER RESEARCH 2023; 245:120576. [PMID: 37713797 DOI: 10.1016/j.watres.2023.120576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 08/18/2023] [Accepted: 09/03/2023] [Indexed: 09/17/2023]
Abstract
Urban stormwater is a primary source of pollution for receiving water, but there is a shortage of studies on pollutant loads from urban catchments in cold regions. In this study, we coupled a build-up and wash-off model (in Mike Urban) with a climate change model to assess the impacts of climate change and urban densification on stormwater nitrogen loads (TN, TKN, NOx-N, and TAN) in an urban catchment in Canada. We calibrated and validated the Mike Urban model against observed event mean concentrations and nitrogen loads from 2010 to 2016. Results show that the nitrogen loads were mainly governed by rainfall intensity, rainfall duration, and antecedent dry days. Future precipitation data were downscaled using the Global Climate Models (GCMs), and three different Representative Concentration Pathways (RCP 2.5, RCP 4.5, and RCP 8.5) were used. Modeling results show that the TN, TKN, NOx-N, and TAN loads in 2050 will increase by 28.5 - 45.2% from May to September under RCP 2.5 compared to those from 2010 to 2016, by 34.6 - 49.9% under RCP 4.5, and by 39.4 - 53.5% under RCP 8.5. The increase of our projected TN load (from 1.33 to 2.93 kg·N/ha) is similar or slightly higher than the limited studies in other urban catchments. This study provides a reference for predicting stormwater nitrogen loads in urban catchments in cold regions.
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Affiliation(s)
- Xiaoyu Zhang
- Dept. of Civil and Environmental Engineering, University of Alberta, Edmonton, AB, Canada T6G 1H9
| | - Shereif H Mahmoud
- Dept. of Civil and Environmental Engineering, University of Alberta, Edmonton, AB, Canada T6G 1H9
| | - Hua Wang
- College of Environment, Hohai University, Nanjing 210098, China
| | - Li Gao
- Institute for Sustainable Industries and Liveable Cities, Victoria University, PO Box 14428, Melbourne, Victoria, 8001, Australia
| | - Mathew Langford
- Dept. of Civil and Environmental Engineering, University of Alberta, Edmonton, AB, Canada T6G 1H9
| | - Wenming Zhang
- Dept. of Civil and Environmental Engineering, University of Alberta, Edmonton, AB, Canada T6G 1H9.
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2
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Rempfert KR, Nothaft DB, Kraus EA, Asamoto CK, Evans RD, Spear JR, Matter JM, Kopf SH, Templeton AS. Subsurface biogeochemical cycling of nitrogen in the actively serpentinizing Samail Ophiolite, Oman. Front Microbiol 2023; 14:1139633. [PMID: 37152731 PMCID: PMC10160414 DOI: 10.3389/fmicb.2023.1139633] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2023] [Accepted: 03/15/2023] [Indexed: 05/09/2023] Open
Abstract
Nitrogen (N) is an essential element for life. N compounds such as ammonium ( NH 4 + ) may act as electron donors, while nitrate ( NO 3 - ) and nitrite ( NO 2 - ) may serve as electron acceptors to support energy metabolism. However, little is known regarding the availability and forms of N in subsurface ecosystems, particularly in serpentinite-hosted settings where hydrogen (H2) generated through water-rock reactions promotes habitable conditions for microbial life. Here, we analyzed N and oxygen (O) isotope composition to investigate the source, abundance, and cycling of N species within the Samail Ophiolite of Oman. The dominant dissolved N species was dependent on the fluid type, with Mg2+- HCO 3 - type fluids comprised mostly of NO 3 - , and Ca2+-OH- fluids comprised primarily of ammonia (NH3). We infer that fixed N is introduced to the serpentinite aquifer as NO 3 - . High concentrations of NO 3 - (>100 μM) with a relict meteoric oxygen isotopic composition (δ18O ~ 22‰, Δ17O ~ 6‰) were observed in shallow aquifer fluids, indicative of NO 3 - sourced from atmospheric deposition (rainwater NO 3 - : δ18O of 53.7‰, Δ17O of 16.8‰) mixed with NO 3 - produced in situ through nitrification (estimated endmember δ18O and Δ17O of ~0‰). Conversely, highly reacted hyperalkaline fluids had high concentrations of NH3 (>100 μM) with little NO 3 - detectable. We interpret that NH3 in hyperalkaline fluids is a product of NO 3 - reduction. The proportionality of the O and N isotope fractionation (18ε / 15ε) measured in Samail Ophiolite NO 3 - was close to unity (18ε / 15ε ~ 1), which is consistent with dissimilatory NO 3 - reduction with a membrane-bound reductase (NarG); however, abiotic reduction processes may also be occurring. The presence of genes commonly involved in N reduction processes (narG, napA, nrfA) in the metagenomes of biomass sourced from aquifer fluids supports potential biological involvement in the consumption of NO 3 - . Production of NH 4 + as the end-product of NO 3 - reduction via dissimilatory nitrate reduction to ammonium (DNRA) could retain N in the subsurface and fuel nitrification in the oxygenated near surface. Elevated bioavailable N in all sampled fluids indicates that N is not likely limiting as a nutrient in serpentinites of the Samail Ophiolite.
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Affiliation(s)
- Kaitlin R. Rempfert
- Department of Geological Sciences, University of Colorado, Boulder, CO, United States
- *Correspondence: Kaitlin R. Rempfert
| | - Daniel B. Nothaft
- Department of Geological Sciences, University of Colorado, Boulder, CO, United States
| | - Emily A. Kraus
- Department of Civil and Environmental Engineering, Colorado School of Mines, Golden, CO, United States
| | - Ciara K. Asamoto
- Department of Geological Sciences, University of Colorado, Boulder, CO, United States
| | - R. Dave Evans
- School of Biological Sciences, Washington State University, Pullman, WA, United States
| | - John R. Spear
- Department of Civil and Environmental Engineering, Colorado School of Mines, Golden, CO, United States
- Quantitative Biosciences and Engineering, Colorado School of Mines, Golden, CO, United States
| | - Juerg M. Matter
- National Oceanography Centre, University of Southampton, Southampton, United Kingdom
| | - Sebastian H. Kopf
- Department of Geological Sciences, University of Colorado, Boulder, CO, United States
| | - Alexis S. Templeton
- Department of Geological Sciences, University of Colorado, Boulder, CO, United States
- Alexis S. Templeton
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3
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Hu Q, Zhu S, Jin Z, Wu A, Chen X, Li F. Using multiple isotopes to identify sources and transport of nitrate in urban residential stormwater runoff. ENVIRONMENTAL MONITORING AND ASSESSMENT 2022; 194:238. [PMID: 35235063 DOI: 10.1007/s10661-022-09763-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2021] [Accepted: 01/07/2022] [Indexed: 06/14/2023]
Abstract
Increased nitrogen (N) from urban stormwater runoff aggravates the deterioration of aquatic ecosystems as urbanisation develops. The sources and transport of nitrate (NO3-) in urban stormwater runoff were investigated by analysing different forms of N, water isotopes (δD-H2O and δ18O-H2O), and NO3- isotopes (δ15N-NO3- and δ18O-NO3-) in urban stormwater runoff in a residential area in Hangzhou, China. The results showed that the concentrations of total N and nitrate N in road runoff were higher than those in roof runoff. Moreover, high concentrations of dissolved organic N and particulate N led to high total nitrogen (TN) concentrations in road runoff (mean: 3.76 mg/L). The high δ18O-NO3- values (mean: + 60 ± 13.1‰) indicated that atmospheric deposition was the predominant NO3- source in roof runoff, as confirmed by the Bayesian isotope mixing model (SIAR model), contributing 84-98% to NO3-. Atmospheric deposition (34-92%) and chemical fertilisers (6.2-54%) were the main NO3- sources for the road runoff. The proportional contributions from soil and organic N were small in the road runoff and roof runoff. For the initial period, the NO3- contributions from atmospheric deposition and chemical fertilisers were higher and lower, respectively, than those in the middle and late periods in road runoff during storm events 3 and 4, while an opposite trend of road runoff in storm event 7 highlighted the influence of short antecedent dry weather period. Reducing impervious areas and more effective management of fertiliser application in urban green land areas were essential to minimize the presence of N in urban aquatic ecosystems.
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Affiliation(s)
- Qiyue Hu
- College of Environment, Zhejiang University of Technology, Hangzhou, 310032, China
| | - Song Zhu
- Zhejiang Construction Investment Environment Engineering Co., Ltd, Hangzhou, 31000, China
| | - Zanfang Jin
- College of Environment, Zhejiang University of Technology, Hangzhou, 310032, China.
| | - Aijing Wu
- College of Environment, Zhejiang University of Technology, Hangzhou, 310032, China
| | - Xiaoyu Chen
- College of Environment, Zhejiang University of Technology, Hangzhou, 310032, China
| | - Feili Li
- College of Environment, Zhejiang University of Technology, Hangzhou, 310032, China
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4
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Zhang P, Chen L, Yan T, Liu J, Shen Z. Sources of nitrate‑nitrogen in urban runoff over and during rainfall events with different grades. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 808:152069. [PMID: 34863734 DOI: 10.1016/j.scitotenv.2021.152069] [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: 09/28/2021] [Revised: 11/12/2021] [Accepted: 11/26/2021] [Indexed: 06/13/2023]
Abstract
Nitrogen discharged from urban areas greatly deteriorates the water quality of downstream surface water. In this study, sub-hourly high-frequency samples of urban runoff during six rainfall events were collected at the outfall of the stormwater network in an urban watershed in Beijing to explore nitrate export and transportation. Isotopic values of local road dust, soil, and network sediment were measured and used as the sources of nitrate to better elucidate the sources of the urban watershed. The contributions of various sources over and during three rainfall events with different grades were quantified and compared. The results showed that the contribution of sources changed dramatically over and during rainfall events. Along with the increase in the total rainfall amount and the going on of rainfall events, the wash-off effect in the atmosphere and on land surfaces played a more important role in nitrate output. Atmospheric deposition was the dominant contributor of nitrate in heavy and storm events (mean 59.3% and 64.8%, respectively). Network sediment contributed large proportions of nitrate in moderate and heavy events (mean 35.6% and 15.9%, respectively). The contribution of soil increased substantially in the storm event (mean 26.1%). Road dust and network sediment contributed greatly in the early stage of the heavy event. The contribution of fertilizer in heavy events was mainly because of the wash-off of road dust. The changing pattern of sources from atmospheric deposition to inorganic N fertilizer existed during the process of the storm event. The contribution of NO3- fertilizer from soil surfaces increased substantially in the later stage of the storm event. These results provide valuable references for urban nutrient management and mitigation measures implementation.
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Affiliation(s)
- Pu Zhang
- State Key Laboratory of Water Environment, School of Environment, Beijing Normal University, Beijing 100875, PR China; College of Energy and Environmental Engineering, Hebei University of Engineering, Handan 056038, PR China
| | - Lei Chen
- State Key Laboratory of Water Environment, School of Environment, Beijing Normal University, Beijing 100875, PR China
| | - Tiezhu Yan
- Key Laboratory of Nonpoint Source Pollution Control, Ministry of Agriculture and Rural Affairs, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, PR China
| | - Jin Liu
- Hebei Key Laboratory of Environmental Change and Ecological Construction, Hebei Technology Innovation Center for Remote Sensing Identification of Environmental Change, College of Geographical Sciences, Hebei Normal University, Shijiazhuang 050024, PR China
| | - Zhenyao Shen
- State Key Laboratory of Water Environment, School of Environment, Beijing Normal University, Beijing 100875, PR China.
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5
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Terrestrial Nitrogen Inputs Affect the Export of Unprocessed Atmospheric Nitrate to Surface Waters: Insights from Triple Oxygen Isotopes of Nitrate. Ecosystems 2021. [DOI: 10.1007/s10021-021-00722-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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6
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Kaushal SS, Wood KL, Galella JG, Gion AM, Haq S, Goodling PJ, Haviland KA, Reimer JE, Morel CJ, Wessel B, Nguyen W, Hollingsworth JW, Mei K, Leal J, Widmer J, Sharif R, Mayer PM, Johnson TAN, Newcomb KD, Smith E, Belt KT. Making 'Chemical Cocktails' - Evolution of Urban Geochemical Processes across the Periodic Table of Elements. APPLIED GEOCHEMISTRY : JOURNAL OF THE INTERNATIONAL ASSOCIATION OF GEOCHEMISTRY AND COSMOCHEMISTRY 2020; 119:1-104632. [PMID: 33746355 PMCID: PMC7970522 DOI: 10.1016/j.apgeochem.2020.104632] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Urbanization contributes to the formation of novel elemental combinations and signatures in terrestrial and aquatic watersheds, also known as 'chemical cocktails.' The composition of chemical cocktails evolves across space and time due to: (1) elevated concentrations from anthropogenic sources, (2) accelerated weathering and corrosion of the built environment, (3) increased drainage density and intensification of urban water conveyance systems, and (4) enhanced rates of geochemical transformations due to changes in temperature, ionic strength, pH, and redox potentials. Characterizing chemical cocktails and underlying geochemical processes is necessary for: (1) tracking pollution sources using complex chemical mixtures instead of individual elements or compounds; (2) developing new strategies for co-managing groups of contaminants; (3) identifying proxies for predicting transport of chemical mixtures using continuous sensor data; and (4) determining whether interactive effects of chemical cocktails produce ecosystem-scale impacts greater than the sum of individual chemical stressors. First, we discuss some unique urban geochemical processes which form chemical cocktails, such as urban soil formation, human-accelerated weathering, urban acidification-alkalinization, and freshwater salinization syndrome. Second, we review and synthesize global patterns in concentrations of major ions, carbon and nutrients, and trace elements in urban streams across different world regions and make comparisons with reference conditions. In addition to our global analysis, we highlight examples from some watersheds in the Baltimore-Washington DC region, which show increased transport of major ions, trace metals, and nutrients across streams draining a well-defined land-use gradient. Urbanization increased the concentrations of multiple major and trace elements in streams draining human-dominated watersheds compared to reference conditions. Chemical cocktails of major and trace elements were formed over diurnal cycles coinciding with changes in streamflow, dissolved oxygen, pH, and other variables measured by high-frequency sensors. Some chemical cocktails of major and trace elements were also significantly related to specific conductance (p<0.05), which can be measured by sensors. Concentrations of major and trace elements increased, peaked, or decreased longitudinally along streams as watershed urbanization increased, which is consistent with distinct shifts in chemical mixtures upstream and downstream of other major cities in the world. Our global analysis of urban streams shows that concentrations of multiple elements along the Periodic Table significantly increase when compared with reference conditions. Furthermore, similar biogeochemical patterns and processes can be grouped among distinct mixtures of elements of major ions, dissolved organic matter, nutrients, and trace elements as chemical cocktails. Chemical cocktails form in urban waters over diurnal cycles, decades, and throughout drainage basins. We conclude our global review and synthesis by proposing strategies for monitoring and managing chemical cocktails using source control, ecosystem restoration, and green infrastructure. We discuss future research directions applying the watershed chemical cocktail approach to diagnose and manage environmental problems. Ultimately, a chemical cocktail approach targeting sources, transport, and transformations of different and distinct elemental combinations is necessary to more holistically monitor and manage the emerging impacts of chemical mixtures in the world's fresh waters.
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Affiliation(s)
- Sujay S Kaushal
- Department of Geology, University of Maryland, College Park, Maryland 20740, USA
- Earth System Science Interdisciplinary Center, University of Maryland, College Park, Maryland 20740, USA
| | - Kelsey L Wood
- Department of Geology, University of Maryland, College Park, Maryland 20740, USA
- Earth System Science Interdisciplinary Center, University of Maryland, College Park, Maryland 20740, USA
| | - Joseph G Galella
- Department of Geology, University of Maryland, College Park, Maryland 20740, USA
- Earth System Science Interdisciplinary Center, University of Maryland, College Park, Maryland 20740, USA
| | - Austin M Gion
- Department of Geology, University of Maryland, College Park, Maryland 20740, USA
| | - Shahan Haq
- Department of Geology, University of Maryland, College Park, Maryland 20740, USA
- Earth System Science Interdisciplinary Center, University of Maryland, College Park, Maryland 20740, USA
| | - Phillip J Goodling
- MD-DE-DC US Geological Survey Water Science Center, 5522 Research Park Drive, Catonsville, Maryland 21228, USA
| | | | - Jenna E Reimer
- Department of Geology, University of Maryland, College Park, Maryland 20740, USA
- Earth System Science Interdisciplinary Center, University of Maryland, College Park, Maryland 20740, USA
| | - Carol J Morel
- Department of Geology, University of Maryland, College Park, Maryland 20740, USA
- Earth System Science Interdisciplinary Center, University of Maryland, College Park, Maryland 20740, USA
| | - Barret Wessel
- Department of Environmental Science and Technology, University of Maryland, College Park, Maryland 20740, USA
| | - William Nguyen
- Department of Geology, University of Maryland, College Park, Maryland 20740, USA
- Earth System Science Interdisciplinary Center, University of Maryland, College Park, Maryland 20740, USA
| | - John W Hollingsworth
- Department of Geology, University of Maryland, College Park, Maryland 20740, USA
| | - Kevin Mei
- Department of Geology, University of Maryland, College Park, Maryland 20740, USA
| | - Julian Leal
- Department of Geology, University of Maryland, College Park, Maryland 20740, USA
| | - Jacob Widmer
- Department of Geology, University of Maryland, College Park, Maryland 20740, USA
| | - Rahat Sharif
- Department of Environmental Science and Technology, University of Maryland, College Park, Maryland 20740, USA
| | - Paul M Mayer
- US Environmental Protection Agency, Center for Public Health and Environmental Assessment, Pacific Ecological Systems Division, Western Ecology Division, 200 SW 35 Street, Corvallis, Oregon 97333, USA
| | - Tamara A Newcomer Johnson
- US Environmental Protection Agency, Center for Environmental Measurement and Modeling, Watershed and Ecosystem Characterization Division, 26 W. Martin Luther King Drive, Cincinnati, Ohio 45268, USA
| | | | - Evan Smith
- Department of Geology, University of Maryland, College Park, Maryland 20740, USA
- Earth System Science Interdisciplinary Center, University of Maryland, College Park, Maryland 20740, USA
| | - Kenneth T Belt
- Department of Geography and Environmental Systems, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, Maryland 21250
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Huang S, Wang F, Elliott EM, Zhu F, Zhu W, Koba K, Yu Z, Hobbie EA, Michalski G, Kang R, Wang A, Zhu J, Fu S, Fang Y. Multiyear Measurements on Δ 17O of Stream Nitrate Indicate High Nitrate Production in a Temperate Forest. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:4231-4239. [PMID: 32157884 DOI: 10.1021/acs.est.9b07839] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Nitrification is a crucial step in ecosystem nitrogen (N) cycling, but scaling up from plot-based measurements of gross nitrification to catchments is difficult. Here, we employed a newly developed method in which the oxygen isotope anomaly (Δ17O) of nitrate (NO3-) is used as a natural tracer to quantify in situ catchment-scale gross nitrification rate (GNR) for a temperate forest from 2014 to 2017 in northeastern China. The annual GNR ranged from 71 to 120 kg N ha-1 yr-1 (average 94 ± 10 kg N ha-1 yr-1) over the 4 years in this forest. This result and high stream NO3- loss (4.2-8.9 kg N ha-1 yr-1) suggest that the forested catchment may have been N-saturated. At the catchment scale, the total N output of 10.7 kg N ha-1 yr-1, via leaching and gaseous losses, accounts for 56% of the N input from bulk precipitation (19.2 kg N ha-1 yr-1). This result indicates that the forested catchment is still retaining a large fraction of N from atmospheric deposition. Our study suggests that estimating in situ catchment-scale GNR over several years when combined with other conventional flux estimates can facilitate the understanding of N biogeochemical cycling and changes in the ecosystem N status.
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Affiliation(s)
- Shaonan Huang
- CAS Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110164, China
- Key Laboratory of Geospatial Technology for the Middle and Lower Yellow River Regions, Ministry of Education, College of Environment and Planning, Henan University, Kaifeng 475004, China
| | - Fan Wang
- School of Atmospheric Sciences, Guangdong Province Key Laboratory for Climate Change and Natural Disaster Studies, Sun Yat-sen University, Zhuhai, Guangdong Province 519082, China
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, Guangdong Province 519082, China
| | - Emily M Elliott
- Department of Geology & Environmental Science, University of Pittsburgh, 4107 O' Hara Street, Pittsburgh, Pennsylvania 15260, United States
| | - Feifei Zhu
- CAS Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110164, China
- Key Laboratory of Stable Isotope Techniques and Applications, Shenyang, Liaoning Province 110016, China
- Qingyuan Forest CERN, Chinese Academy of Sciences, Shenyang, Liaoning 110014, China
| | - Weixing Zhu
- Department of Biological Sciences, Binghamton University, The State University of New York, Binghamton, New York 13902, United States
| | - Keisuke Koba
- Center for Ecological Research, Kyoto University, Shiga 520-2113, Japan
| | - Zhongjie Yu
- Department of Soil, Water, and Climate, University of Minnesota, St. Paul, Minnesota 55108, United States
| | - Erik A Hobbie
- Earth Systems Research Center, University of New Hampshire, Durham, New Hampshire 03824, United States
| | - Greg Michalski
- Department of Chemistry, Department of Earth, Atmospheric, and Planetary Sciences, Purdue University, 560 Oval Drive, West Lafayette, Indiana 47907, United States
| | - Ronghua Kang
- CAS Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110164, China
- Qingyuan Forest CERN, Chinese Academy of Sciences, Shenyang, Liaoning 110014, China
| | - Anzhi Wang
- CAS Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110164, China
| | - Jiaojun Zhu
- CAS Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110164, China
- Qingyuan Forest CERN, Chinese Academy of Sciences, Shenyang, Liaoning 110014, China
| | - Shenglei Fu
- Key Laboratory of Geospatial Technology for the Middle and Lower Yellow River Regions, Ministry of Education, College of Environment and Planning, Henan University, Kaifeng 475004, China
| | - Yunting Fang
- CAS Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110164, China
- Key Laboratory of Stable Isotope Techniques and Applications, Shenyang, Liaoning Province 110016, China
- Qingyuan Forest CERN, Chinese Academy of Sciences, Shenyang, Liaoning 110014, China
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8
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Hattori S, Nuñez Palma Y, Itoh Y, Kawasaki M, Fujihara Y, Takase K, Yoshida N. Isotopic evidence for seasonality of microbial internal nitrogen cycles in a temperate forested catchment with heavy snowfall. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 690:290-299. [PMID: 31291607 DOI: 10.1016/j.scitotenv.2019.06.507] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Revised: 06/28/2019] [Accepted: 06/29/2019] [Indexed: 06/09/2023]
Abstract
The Hokuriku district of central Japan receives high levels of precipitation during winter, largely in the form of snow. This study aimed to elucidate the internal nitrogen dynamics in this temperate forested region with heavy snowfall using the triple oxygen and nitrogen isotopic compositions of NO3-. The isotopic compositions of NO3- in atmospheric depositions (P and Tf), with terrestrial components of the soil layer (A0, S25, S55, and S90), ground water (G), and output (St) were measured from 2015 to 2016 in a forested catchment located in the southern area of the Ishikawa Prefecture, Japan. Seasonal distributions of Δ17O(NO3-) showed a decreasing trend from the inputs to outputs of the ecosystem. We found relatively constant Δ17O(NO3-) values in the output components (G and St), but found highly fluctuating Δ17O(NO3-) values resulting from the seasonal variations in the nitrification activity within soil waters. Specifically, we observed a lower nitrifying activity in the top soil layer throughout cold periods, presumably due to the input of cold melted snow water. The general trend of increasing δ15N(NO3-) value from the input to output components, with the changes in denitrification hotspots from shallow to deeper soil layer, can be observed between warm and cold periods. Thus, the seasonal changes of hotspots related to microbial nitrification and denitrification could be noted due to the seasonal changes in the isotopic compositions of nitrate. The estimated ecosystem-scale gross nitrification and denitrification rates are low; however, the output components are relatively stable with low concentrations of nitrate, indicating that the plant uptake of nitrogen most probably occurs at greater rates and scales in this forested ecosystem. Future nitrogen deposition and the vulnerable dynamics of snow melting are likely to have impactful consequences on such localities.
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Affiliation(s)
- Shohei Hattori
- Department of Chemical Science and Engineering, School of Materials and Chemical Technology, Tokyo Institute of Technology, 4529 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8502, Japan.
| | - Yoshio Nuñez Palma
- Department of Environmental Chemistry and Engineering, Interdisciplinary Graduate School of Science and Engineering and Engineering, Tokyo Institute of Technology, 4529 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8502, Japan
| | - Yuko Itoh
- Forestry and Forest Products Research Institute (FFPRI), 1 Matsunosato, Tsukuba, Ibaraki 305-8687, Japan
| | - Moeko Kawasaki
- Nakanoto General Agriculture and Forestry Office, Ishikawa Prefecture, 33 Ni-bu, Kojima-machi, Nanao, Ishikawa 926-0852, Japan
| | - Yoichi Fujihara
- Faculty of Bioresources and Environmental Sciences, Ishikawa Prefectural University, 1-308, Suematsu, Nonoichi, Ishikawa 921-8836, Japan
| | - Keiji Takase
- Faculty of Bioresources and Environmental Sciences, Ishikawa Prefectural University, 1-308, Suematsu, Nonoichi, Ishikawa 921-8836, Japan
| | - Naohiro Yoshida
- Department of Chemical Science and Engineering, School of Materials and Chemical Technology, Tokyo Institute of Technology, 4529 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8502, Japan; Earth-Life Science Institute (ELSI), Tokyo Institute of Technology, Meguro-ku, Tokyo 152-8550, Japan
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9
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Sugimoto R, Tsuboi T, Fujita MS. Comprehensive and quantitative assessment of nitrate dynamics in two contrasting forested basins along the Sea of Japan using dual isotopes of nitrate. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 687:667-678. [PMID: 31220720 DOI: 10.1016/j.scitotenv.2019.06.090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 06/05/2019] [Accepted: 06/06/2019] [Indexed: 06/09/2023]
Abstract
The recent deposition rates of atmospheric nitrate derived from east Asia to the Japanese forested watershed facing the Sea of Japan are of serious concern. However, export ratios and the seasonality of atmospheric nitrate versus microbial nitrate from forest soils to upstreams have not yet been quantified. Furthermore, the influence of local nitrogen sources and internal biogeochemical processes are still unclear. To determine the influence of watershed properties and atmospheric nitrogen deposition on nitrate dynamics in two adjacent basins (the Kita and Minami Rivers) located in central Japan, we conducted seasonal synoptic surveys using the dual isotopes of nitrate. It was found that nitrate regenerated through nitrification in the forest soil was likely the dominant nitrogen source in both basins from the upstream to downstream waters. However, nitrate concentrations and the direct leaching ratio of atmospheric nitrate were considerably higher in the Kita River Basin than in the Minami River Basin, possibly due to the difference in forest environments. In the Kita River Basin, geographic trait such as altitude may be one factor regulating the sensitivity of forest ecosystem to nitrogen deposition. Quantitative assessments of nitrate outflows from the sub-basins revealed that nitrogen leached from the forest soil was a major source (61-81%) of nitrate loading to the coastal sea.
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Affiliation(s)
- R Sugimoto
- Research Center for Marine Bioresources, Fukui Prefectural University, Obama, Fukui 917-0116, Japan.
| | - T Tsuboi
- Research Center for Marine Bioresources, Fukui Prefectural University, Obama, Fukui 917-0116, Japan
| | - M S Fujita
- Center for Southeast Asian Studies, Kyoto University, Kyoto 606-8501, Japan
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10
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Bourgeois I, Clément JC, Caillon N, Savarino J. Foliar uptake of atmospheric nitrate by two dominant subalpine plants: insights from in situ triple-isotope analysis. THE NEW PHYTOLOGIST 2019; 223:1784-1794. [PMID: 30802966 DOI: 10.1111/nph.15761] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Accepted: 02/19/2019] [Indexed: 06/09/2023]
Abstract
The significance of foliar uptake of nitrogen (N) compounds in natural conditions is not well understood, despite growing evidence of its importance to plant nutrition. In subalpine meadows, N-limitation fosters the dominance of specific subalpine plant species, which in turn ensures the provision of essential ecosystems services. Understanding how these plants absorb N and from which sources is important in predicting ecological consequences of increasing N deposition. Here, we investigate the sources of N to plants from subalpine meadows with distinct land-use history in the French Alps, using the triple isotopes (Δ17 O, δ18 O, and δ15 N) of plant tissue nitrate (NO3- ). We use this approach to evaluate the significance of foliar uptake of atmospheric NO3- (NO3-atm ). The foliar uptake of NO3-atm accounted for 4-16% of the leaf NO3- content, and contributed more to the leaf NO3- pool after peak biomass. Additionally, the gradual 15 N enrichment of NO3- from the soil to the leaves reflected the contribution of NO3-atm assimilation to plants' metabolism. The present study confirms that foliar uptake is a potentially important pathway for NO3-atm into subalpine plants. This is of major significance as N emissions (and deposition) are predicted to increase globally in the future.
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Affiliation(s)
- Ilann Bourgeois
- CNRS, IRD, Grenoble INP, IGE, University of Grenoble Alpes, F-38000, Grenoble, France
- CNRS, LECA, University of Grenoble Alpes, F-38000, Grenoble, France
| | - Jean-Christophe Clément
- CNRS, LECA, University of Grenoble Alpes, F-38000, Grenoble, France
- INRA, CARRTEL, University of Savoie Mont Blanc, F-74200, Thonon-Les Bains, France
| | - Nicolas Caillon
- CNRS, IRD, Grenoble INP, IGE, University of Grenoble Alpes, F-38000, Grenoble, France
| | - Joël Savarino
- CNRS, IRD, Grenoble INP, IGE, University of Grenoble Alpes, F-38000, Grenoble, France
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11
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Elliott EM, Yu Z, Cole AS, Coughlin JG. Isotopic advances in understanding reactive nitrogen deposition and atmospheric processing. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 662:393-403. [PMID: 30690373 PMCID: PMC7092373 DOI: 10.1016/j.scitotenv.2018.12.177] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2018] [Revised: 12/09/2018] [Accepted: 12/11/2018] [Indexed: 05/04/2023]
Abstract
Recent advances in stable isotope measurements now allow for detailed investigations of the sources, transformations, and deposition of reactive nitrogen (N) species. Stable isotopes show promise as a complementary tool for apportioning emissions sources that contribute to deposition and also for developing a more robust understanding of the transformations that can influence these isotope ratios. Methodological advances have facilitated the unprecedented examination of the isotopic composition of reactive N species in the atmosphere and in precipitation including nitrogen oxides (NOx = nitric oxide (NO) + nitrogen dioxide (NO2)), atmospheric nitrate (NO3-), nitric acid (HNO3), ammonia (NH3), and ammonium (NH4+). This isotopic information provides new insight into the mechanisms of transformation and cycling of reactive N in the atmosphere and moreover helps resolve the contribution of multiple NOx and NH3 emission sources to deposition across landscapes, regions, and continents. Here, we highlight the current state of knowledge regarding the isotopic ratios of NOx and NH3 emission sources and chemical alterations of isotopic ratios during atmospheric transformations. We also highlight illustrative examples where isotopic approaches are used and review recent methodological advances. While these highlights are not an exhaustive review of the literature, we hope they provide a glimpse of the potential for these methods to help resolve knowledge gaps regarding total N deposition to Earth surfaces. We conclude with promising opportunities for future research in the short-, medium-, and long-term.
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Affiliation(s)
- Emily M Elliott
- Department of Geology & Environmental Science, University of Pittsburgh, United States of America.
| | - Zhongjie Yu
- Department of Geology & Environmental Science, University of Pittsburgh, United States of America
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12
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Bourgeois I, Savarino J, Némery J, Caillon N, Albertin S, Delbart F, Voisin D, Clément JC. Atmospheric nitrate export in streams along a montane to urban gradient. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 633:329-340. [PMID: 29574377 DOI: 10.1016/j.scitotenv.2018.03.141] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Revised: 03/11/2018] [Accepted: 03/13/2018] [Indexed: 06/08/2023]
Abstract
Nitrogen (N) emissions associated with urbanization exacerbate the atmospheric N influx to remote ecosystems - like mountains -, leading to well-documented detrimental effects on ecosystems (e.g., soil acidification, pollution of freshwaters). Here, the importance and fate of N deposition in a watershed was evaluated along a montane to urban gradient, using a multi-isotopic tracers approach (Δ17O, δ15N, δ18O of nitrate, δ2H and δ18O of water). In this setting, the montane streams had higher proportions of atmospheric nitrate compared to urban streams, and exported more atmospheric nitrate on a yearly basis (0.35 vs 0.10 kg-Nha-1yr-1). In urban areas, nitrate exports were driven by groundwater, whereas in the catchment head nitrate exports were dominated by surface runoff. The main sources of nitrate to the montane streams were microbial nitrification and atmospheric deposition, whereas microbial nitrification and sewage leakage contributed most to urban streams. Based on the measurement of δ15N and δ18O-NO3-, biological processes such as denitrification or N assimilation were not predominant in any streams in this study. The observed low δ15N and δ18O range of terrestrial nitrate (i.e., nitrate not coming from atmospheric deposition) in surface water compared to literature suggests that atmospheric deposition may be underestimated as a direct source of N.
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Affiliation(s)
- Ilann Bourgeois
- Université Grenoble Alpes, CNRS, IRD, Grenoble INP(1), IGE, F-38000 Grenoble, France; Université Grenoble Alpes, CNRS, LECA, F-38000 Grenoble, France.
| | - Joel Savarino
- Université Grenoble Alpes, CNRS, IRD, Grenoble INP(1), IGE, F-38000 Grenoble, France
| | - Julien Némery
- Université Grenoble Alpes, CNRS, IRD, Grenoble INP(1), IGE, F-38000 Grenoble, France
| | - Nicolas Caillon
- Université Grenoble Alpes, CNRS, IRD, Grenoble INP(1), IGE, F-38000 Grenoble, France
| | - Sarah Albertin
- Université Grenoble Alpes, CNRS, IRD, Grenoble INP(1), IGE, F-38000 Grenoble, France
| | - Franck Delbart
- Université Grenoble Alpes, CNRS, SAJF, F-38000 Grenoble, France
| | - Didier Voisin
- Université Grenoble Alpes, CNRS, IRD, Grenoble INP(1), IGE, F-38000 Grenoble, France
| | - Jean-Christophe Clément
- Université Grenoble Alpes, CNRS, LECA, F-38000 Grenoble, France; Université Savoie Mont Blanc, INRA, CARRTEL, F-74200 Thonon-Les Bains, France
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13
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Yang YY, Toor GS. Stormwater runoff driven phosphorus transport in an urban residential catchment: Implications for protecting water quality in urban watersheds. Sci Rep 2018; 8:11681. [PMID: 30076338 PMCID: PMC6076301 DOI: 10.1038/s41598-018-29857-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Accepted: 07/20/2018] [Indexed: 11/18/2022] Open
Abstract
Increased stormwater runoff in urban watersheds is a leading cause of nonpoint phosphorus (P) pollution. We investigated the concentrations, forms, and temporal trends of P in stormwater runoff from a residential catchment (31 low-density residential homes; 0.11 km2 drainage area) in Florida. Unfiltered runoff samples were collected at 5 min intervals over 29 storm events with an autosampler installed at the stormwater outflow pipe. Mean concentrations of orthophosphate (PO4–P) were 0.18 ± 0.065 mg/L and total P (TP) were 0.28 ± 0.062 mg/L in all runoff samples. The PO4–P was the dominant form in >90% of storm events and other–P (combination of organic P and particulate P) was dominant after a longer antecedent dry period. We hypothesize that in the stormwater runoff, PO4–P likely originated from soluble and desorbed pool of eroded soil and other–P likely originated from decomposing plant materials i.e. leaves and grass clippings and eroded soil. We found that the runoff was co-limited with nitrogen (N) and P in 34% of storm events and only N limited in 66% of storm events, implicating that management strategies focusing on curtailing both P and N transport would be more effective than focussing on only N or P in protecting water quality in residential catchments.
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Affiliation(s)
- Yun-Ya Yang
- Department of Environmental Science and Technology, University of Maryland, College Park, MD, 20742, USA
| | - Gurpal S Toor
- Department of Environmental Science and Technology, University of Maryland, College Park, MD, 20742, USA.
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Yang YY, Toor GS. Sources and mechanisms of nitrate and orthophosphate transport in urban stormwater runoff from residential catchments. WATER RESEARCH 2017; 112:176-184. [PMID: 28160697 DOI: 10.1016/j.watres.2017.01.039] [Citation(s) in RCA: 82] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Revised: 01/19/2017] [Accepted: 01/20/2017] [Indexed: 06/06/2023]
Abstract
Nutrients export from residential catchments contributes to water quality impairment in urban water bodies. We investigated the concentrations, transport mechanisms, and sources of nitrate-nitrogen (NO3-N) and orthophosphate-phosphorus (PO4-P) in urban stormwater runoff generated in residential catchments in Tampa Bay, Florida, United States. Street runoff samples, collected over 21 storm events, were supplemented with rainfall and roof runoff samples from six representative residential catchments. Samples were analyzed for N and P forms, N and oxygen (O) isotopes of nitrate (δ18O-NO3- and δ15N-NO3-), and δ18O and hydrogen (δD) isotopes of water (H2O). We found that the main NO3-N source in street runoff was atmospheric deposition (range: 35-64%), followed by chemical N fertilizers (range: 1-39%), and soil and organic N (range: 7-33%), whereas PO4-P in the street runoff likely originated from erosion of soil particles and mineralization from organic materials (leaves, grass clippings). The variability in the sources and concentrations of NO3-N and PO4-P across catchments is attributed to different development designs and patterns, use of various fill materials during land development, and landscaping practices. This data can be useful to develop strategies to offset the impacts of urban development (e.g., designs and patterns resulting in variable impervious areas) and management (e.g., fertilizer use, landscaping practices) on NO3-N and PO4-P transport in urban residential catchments.
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Affiliation(s)
- Yun-Ya Yang
- Soil and Water Quality Laboratory, Gulf Coast Research and Education Center, University of Florida, Institute of Food and Agricultural Sciences, 14625 CR 672, Wimauma, FL 33598, USA
| | - Gurpal S Toor
- Soil and Water Quality Laboratory, Gulf Coast Research and Education Center, University of Florida, Institute of Food and Agricultural Sciences, 14625 CR 672, Wimauma, FL 33598, USA.
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15
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Mautner A, Kobkeatthawin T, Bismarck A. Efficient continuous removal of nitrates from water with cationic cellulose nanopaper membranes. RESOURCE-EFFICIENT TECHNOLOGIES 2017. [DOI: 10.1016/j.reffit.2017.01.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/07/2022]
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Yu L, Zhu J, Mulder J, Dörsch P. Multiyear dual nitrate isotope signatures suggest that N-saturated subtropical forested catchments can act as robust N sinks. GLOBAL CHANGE BIOLOGY 2016; 22:3662-3674. [PMID: 27124387 DOI: 10.1111/gcb.13333] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Accepted: 04/02/2016] [Indexed: 06/05/2023]
Abstract
In forests of the humid subtropics of China, chronically elevated nitrogen (N) deposition, predominantly as ammonium (NH4+ ), causes significant nitrate (NO3- ) leaching from well-drained acid forest soils on hill slopes (HS), whereas significant retention of NO3- occurs in near-stream environments (groundwater discharge zones, GDZ). To aid our understanding of N transformations on the catchment level, we studied spatial and temporal variabilities of concentration and natural abundance (δ15 N and δ18 O) of nitrate (NO3- ) in soil pore water along a hydrological continuum in the N-saturated Tieshanping (TSP) catchment, southwest China. Our data show that effective removal of atmogenic NH4+ and production of NO3- in soils on HS were associated with a significant decrease in δ15 N-NO3- , suggesting efficient nitrification despite low soil pH. The concentration of NO3- declined sharply along the hydrological flow path in the GDZ. This decline was associated with a significant increase in both δ15 N and δ18 O of residual NO3- , providing evidence that the GDZ acts as an N sink due to denitrification. The observed apparent 15 N enrichment factor (ε) of NO3- of about -5‰ in the GDZ is similar to values previously reported for efficient denitrification in riparian and groundwater systems. Episode studies in the summers of 2009, 2010 and 2013 revealed that the spatial pattern of δ15 N and δ18 O-NO3- in soil water was remarkably similar from year to year. The importance of denitrification as a major N sink was also seen at the catchment scale, as largest δ15 N-NO3- values in stream water were observed at lowest discharge, confirming the importance of the relatively small GDZ for N removal under base flow conditions. This study, explicitly recognizing hydrologically connected landscape elements, reveals an overlooked but robust N sink in N-saturated, subtropical forests with important implications for regional N budgets.
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Affiliation(s)
- Longfei Yu
- Department of Environmental Sciences, Norwegian University of Life Sciences, Postbox 5003, N-1432, Aas, Norway
| | - Jing Zhu
- Department of Environmental Sciences, Norwegian University of Life Sciences, Postbox 5003, N-1432, Aas, Norway
- Department of Environment and Resources, Guangxi Normal University, 541004, Guilin, China
| | - Jan Mulder
- Department of Environmental Sciences, Norwegian University of Life Sciences, Postbox 5003, N-1432, Aas, Norway
| | - Peter Dörsch
- Department of Environmental Sciences, Norwegian University of Life Sciences, Postbox 5003, N-1432, Aas, Norway.
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17
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Scale-dependent linkages between nitrate isotopes and denitrification in surface soils: implications for isotope measurements and models. Oecologia 2016; 181:1221-31. [DOI: 10.1007/s00442-016-3626-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2015] [Accepted: 04/01/2016] [Indexed: 10/21/2022]
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18
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Hall SJ, Weintraub SR, Eiriksson D, Brooks PD, Baker MA, Bowen GJ, Bowling DR. Stream Nitrogen Inputs Reflect Groundwater Across a Snowmelt-Dominated Montane to Urban Watershed. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:1137-1146. [PMID: 26744921 DOI: 10.1021/acs.est.5b04805] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Snowmelt dominates the hydrograph of many temperate montane streams, yet little work has characterized how streamwater sources and nitrogen (N) dynamics vary across wildland to urban land use gradients in these watersheds. Across a third-order catchment in Salt Lake City, Utah, we asked where and when groundwater vs shallow surface water inputs controlled stream discharge and N dynamics. Stream water isotopes (δ(2)H and δ(18)O) reflected a consistent snowmelt water source during baseflow. Near-chemostatic relationships between conservative ions and discharge implied that groundwater dominated discharge year-round across the montane and urban sites, challenging the conceptual emphasis on direct stormwater inputs to urban streams. Stream and groundwater NO3(-) concentrations remained consistently low during snowmelt and baseflow in most montane and urban stream reaches, indicating effective subsurface N retention or denitrification and minimal impact of fertilizer or deposition N sources. Rather, NO3(-) concentrations increased 50-fold following urban groundwater inputs, showing that subsurface flow paths potentially impact nutrient loading more than surficial land use. Isotopic composition of H2O and NO3(-) suggested that snowmelt-derived urban groundwater intercepted NO3(-) from leaking sewers. Sewer maintenance could potentially mitigate hotspots of stream N inputs at mountain/valley transitions, which have been largely overlooked in semiarid urban ecosystems.
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Affiliation(s)
| | - Samantha R Weintraub
- Department of Geology and Geophysics, University of Utah , 115 South 1460 East, Salt Lake City, Utah 84112, United States
| | | | - Paul D Brooks
- Department of Geology and Geophysics, University of Utah , 115 South 1460 East, Salt Lake City, Utah 84112, United States
| | - Michelle A Baker
- Department of Biology and the Ecology Center, Utah State University , 5305 Old Main Hill, Logan, Utah 84322, United States
| | - Gabriel J Bowen
- Department of Geology and Geophysics, University of Utah , 115 South 1460 East, Salt Lake City, Utah 84112, United States
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19
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Guerrieri R, Vanguelova EI, Michalski G, Heaton THE, Mencuccini M. Isotopic evidence for the occurrence of biological nitrification and nitrogen deposition processing in forest canopies. GLOBAL CHANGE BIOLOGY 2015; 21:4613-4626. [PMID: 26146936 DOI: 10.1111/gcb.13018] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Revised: 06/11/2015] [Accepted: 06/16/2015] [Indexed: 05/28/2023]
Abstract
This study examines the role of tree canopies in processing atmospheric nitrogen (Ndep ) for four forests in the United Kingdom subjected to different Ndep : Scots pine and beech stands under high Ndep (HN, 13-19 kg N ha(-1) yr(-1) ), compared to Scots pine and beech stands under low Ndep (LN, 9 kg N ha(-1) yr(-1) ). Changes of NO3 -N and NH4 -N concentrations in rainfall (RF) and throughfall (TF) together with a quadruple isotope approach, which combines δ(18) O, Δ(17) O and δ(15) N in NO3 (-) and δ(15) N in NH4 (+) , were used to assess N transformations by the canopies. Generally, HN sites showed higher NH4 -N and NO3 -N concentrations in RF compared to the LN sites. Similar values of δ(15) N-NO3 (-) and δ(18) O in RF suggested similar source of atmospheric NO3 (-) (i.e. local traffic), while more positive values for δ(15) N-NH4 (+) at HN compared to LN likely reflected the contribution of dry NHx deposition from intensive local farming. The isotopic signatures of the N-forms changed after interacting with tree canopies. Indeed, (15) N-enriched NH4 (+) in TF compared to RF at all sites suggested that canopies played an important role in buffering dry Ndep also at the low Ndep site. Using two independent methods, based on δ(18) O and Δ(17) O, we quantified for the first time the proportion of NO3 (-) in TF, which derived from nitrification occurring in tree canopies at the HN site. Specifically, for Scots pine, all the considered isotope approaches detected biological nitrification. By contrast for the beech, only using the mixing model with Δ(17) O, we were able to depict the occurrence of nitrification within canopies. Our study suggests that tree canopies play an active role in the N cycling within forest ecosystems. Processing of Ndep within canopies should not be neglected and needs further exploration, with the combination of multiple isotope tracers, with particular reference to Δ(17) O.
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Affiliation(s)
- Rossella Guerrieri
- Earth Systems Research Center, University of New Hampshire, Morse Hall, 8 College Rd, Durham, NH, 03824, USA
- School of GeoSciences, University of Edinburgh, Crew Building, West Mains Road, Edinburgh, EH9 3JN, UK
| | - Elena I Vanguelova
- Centre of Ecosystem, Society and Biosecurity, Forest Research, Alice Holt Lodge, Farnham, Surrey, GU10 4LH, UK
| | - Greg Michalski
- Department of Earth, Atmospheric, and Planetary Sciences, Purdue University, 550 Stadium Mell Drive, West Lafayette, IN, 47907, USA
| | - Timothy H E Heaton
- NERC Isotope Geosciences Laboratory, British Geological Survey, Keyworth, Nottingham, NG12 5GG, UK
| | - Maurizio Mencuccini
- School of GeoSciences, University of Edinburgh, Crew Building, West Mains Road, Edinburgh, EH9 3JN, UK
- ICREA at CREAF, Cerdanyola del Valles, 08023, Barcelona, Spain
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Triple Nitrate Isotopes Indicate Differing Nitrate Source Contributions to Streams Across a Nitrogen Saturation Gradient. Ecosystems 2015. [DOI: 10.1007/s10021-015-9891-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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21
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Microbial denitrification dominates nitrate losses from forest ecosystems. Proc Natl Acad Sci U S A 2015; 112:1470-4. [PMID: 25605898 DOI: 10.1073/pnas.1416776112] [Citation(s) in RCA: 88] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Denitrification removes fixed nitrogen (N) from the biosphere, thereby restricting the availability of this key limiting nutrient for terrestrial plant productivity. This microbially driven process has been exceedingly difficult to measure, however, given the large background of nitrogen gas (N2) in the atmosphere and vexing scaling issues associated with heterogeneous soil systems. Here, we use natural abundance of N and oxygen isotopes in nitrate (NO3 (-)) to examine dentrification rates across six forest sites in southern China and central Japan, which span temperate to tropical climates, as well as various stand ages and N deposition regimes. Our multiple stable isotope approach across soil to watershed scales shows that traditional techniques underestimate terrestrial denitrification fluxes by up to 98%, with annual losses of 5.6-30.1 kg of N per hectare via this gaseous pathway. These N export fluxes are up to sixfold higher than NO3 (-) leaching, pointing to widespread dominance of denitrification in removing NO3 (-) from forest ecosystems across a range of conditions. Further, we report that the loss of NO3 (-) to denitrification decreased in comparison to leaching pathways in sites with the highest rates of anthropogenic N deposition.
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