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Chen R, Shen W, Tong C, Guo J, Yang L, Ma X, Xin H, Yao Y, Wang L. Contrasting nitrogen transport patterns in subtropical basins revealed by combined multiple isotopic analyzes and hydrological simulations. WATER RESEARCH 2024; 262:122058. [PMID: 39013261 DOI: 10.1016/j.watres.2024.122058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2024] [Revised: 06/14/2024] [Accepted: 07/04/2024] [Indexed: 07/18/2024]
Abstract
Although enhancing the knowledge of nitrogen (N) dynamics in aquatic systems is crucial for basin N management, there is still a lack of theories on the patterns of basin N sources and transport because of the intricate influence of human activities, climatic conditions, landscape patterns, and topography on the trajectory of basin N. To shed new light on the patterns of basin N sources and transport in the Chinese subtropical monsoon region, this study provides a comprehensive approach combining multiple isotopes and hydrological model based on monthly records of hydro-chemistry and isotopes (18O-NO3- /15N-NO-3 and 18O-H2O /2H-H2O) for river water, groundwater and rainfall in three basins over multiple years. Our observations of hydro-chemistry showed that fluvial N levels in highly urbanized basins (3.05 ± 1.42 mg·L-1) were the highest and were characterized by higher levels in the dry season. In the agricultural basin, fluvial N levels in February and March were approximately 1.9 times higher than those in the other months. The fluvial N load was higher in agricultural basins (0.624-0.728 T N km -2 y -1) than in urban basins (0.558 T N km -2 y -1), primarily because of variations in sewage treatment rates and fertilizer application. In highly urbanized basin, manure and sewage (46.9 %) were the dominant sources of fluvial N, which were discharged into rivers after treatment. In the plain agricultural basin, a substantial portion of diffused residential sewage leaches into aquifers and is stored. In the hilly agro-forest mixed basin, the high baseflow coefficient (75.8 %) and the key role of groundwater N, mainly from soil N (27.3 %), chemical fertilizers (20.2 %), manure and sewage (46.6 %), to fluvial N (26.5 %) indicated that a high proportion of the N sources leached into the aquifer and were then transported to rivers. For the first time, this study integrated multiple methods to substantiate the proposed typical patterns of N sources and transport within the basins. These findings have significant implications for tailored basin-specific N management strategies.
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Affiliation(s)
- Ruidong Chen
- School of Geography and Ocean Science, Nanjing University, Nanjing, Jiangsu province, 210023, PR China
| | - Wanqi Shen
- School of Geography and Ocean Science, Nanjing University, Nanjing, Jiangsu province, 210023, PR China
| | - Chengwei Tong
- School of Geography and Ocean Science, Nanjing University, Nanjing, Jiangsu province, 210023, PR China
| | - Jiaxun Guo
- Center for Water and Ecology, State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, PR China
| | - Long Yang
- School of Geography and Ocean Science, Nanjing University, Nanjing, Jiangsu province, 210023, PR China
| | - Xiaoxue Ma
- College of Urban Resources and Environment, Jiangsu Second Normal University, Nanjing, 210013, PR China
| | - Huarong Xin
- Jiangsu Province Hydrology and Water Resources Investigation Bureau, Nanjing, Jiangsu province, 210029, PR China
| | - Yunlong Yao
- Jiangsu Province Hydrology and Water Resources Investigation Bureau, Nanjing, Jiangsu province, 210029, PR China
| | - Lachun Wang
- School of Geography and Ocean Science, Nanjing University, Nanjing, Jiangsu province, 210023, PR China.
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Xi S, Liu H, Zhang J, Hu L, Wang W. Key factors affecting NH 3-N in the Huaihe River Basin due to human activities. ENVIRONMENTAL GEOCHEMISTRY AND HEALTH 2024; 46:218. [PMID: 38849659 DOI: 10.1007/s10653-024-01967-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Accepted: 03/25/2024] [Indexed: 06/09/2024]
Abstract
Human activity factors have a significant impact on changes in ammonia nitrogen (NH3-N) content in rivers. Existing research mainly focuses on human activity factors as type factors, and lacks research on the key factors affecting river NH3-N among human activity factors. Therefore, this paper aims to study the key factors affecting human activities on NH3-N in the Huaihe River through various statistical analysis methods. The study found that changes in NH3-N content in the Huaihe River are mainly affected by land use patterns in the basin. There are two different ways in which land use affects NH3-N in rivers: direct effects and indirect effects. We also studied the main pathways through which changes in key factors in human activities affect NH3-N in the Huaihe River by constructing a structural equation model. The results showed that crop sowing area and afforestation area have a significant direct effect on NH3-N in the Huaihe River. In addition, crop sowing area and afforestation area can also affect river NH3-N by regulating the amount of nitrogen fertilizer and human excrement. This study is of great significance for understanding how human activities regulate NH3-N content in rivers.
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Affiliation(s)
- Shanshan Xi
- School of Environmental and Energy Engineering, Anhui Jianzhu University, 292, Ziyun Rd., Shushan District, Hefei City, 230601, Anhui Province, People's Republic of China
- Anhui Provincial Institute of Ecological Civilization, Hefei, Anhui, People's Republic of China
- Anhui Province Tongyuan Environmental Environment Co. Ltd, Hefei, Anhui, People's Republic of China
| | - Hao Liu
- School of Environmental and Energy Engineering, Anhui Jianzhu University, 292, Ziyun Rd., Shushan District, Hefei City, 230601, Anhui Province, People's Republic of China.
- Anhui Provincial Institute of Ecological Civilization, Hefei, Anhui, People's Republic of China.
| | - Jiamei Zhang
- School of Environmental and Energy Engineering, Anhui Jianzhu University, 292, Ziyun Rd., Shushan District, Hefei City, 230601, Anhui Province, People's Republic of China
- Anhui Provincial Institute of Ecological Civilization, Hefei, Anhui, People's Republic of China
| | - Lechang Hu
- School of Environmental and Energy Engineering, Anhui Jianzhu University, 292, Ziyun Rd., Shushan District, Hefei City, 230601, Anhui Province, People's Republic of China
- Anhui Provincial Institute of Ecological Civilization, Hefei, Anhui, People's Republic of China
| | - Wei Wang
- School of Environmental and Energy Engineering, Anhui Jianzhu University, 292, Ziyun Rd., Shushan District, Hefei City, 230601, Anhui Province, People's Republic of China
- Anhui Provincial Institute of Ecological Civilization, Hefei, Anhui, People's Republic of China
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Kang L, Zhu M, Zhu G, Xu H, Zou W, Xiao M, Guo C, Zhang Y, Qin B. Decreasing denitrification rates poses a challenge to further decline of nitrogen concentration in Lake Taihu, China. WATER RESEARCH 2024; 256:121565. [PMID: 38581985 DOI: 10.1016/j.watres.2024.121565] [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: 01/02/2024] [Revised: 02/29/2024] [Accepted: 04/01/2024] [Indexed: 04/08/2024]
Abstract
Nitrogen (N) concentrations in many lakes have decreased substantially in recent years due to external load reduction to mitigate harmful algal blooms. However, little attention has been paid to the linkage between the lakes' nitrogen removal efficiency and improved water quality in lakes, especially the variation of denitrification rate (DNR) under decreasing N concentrations. To understand the efficiency of N removal under improving water quality and its influence on the N control targets in Lake Taihu, a denitrification model based on in situ experimental results was developed and long-term (from 2007 to 2022) water quality and meteorological observations were used to estimate DNR and relate it to the amount of N removal (ANR) from the lake. The concentration of total nitrogen (TN) in Lake Taihu decreased from 3.28 mg L-1 to 1.41 mg L-1 from 2007 to 2022 but the reduction showed spatial heterogeneity. The annual mean DNR decreased from 45.6 μmol m-2 h-1 to 4.2 μmol m-2 h-1, and ANR decreased from 11.85×103 t yr-1 to 1.17×103 t yr-1 during the study years. N budget analysis suggested that the amount of N removed by denitrification accounted for 23.3 % of the external load in 2007, but decreased to only 4.0 % in 2022. Thus, the contribution of N removal by internal N cycling decreased significantly as water quality improved. Notably, the proportion of ANR in winter to total ANR increased from 14 % in 2007 to 23 % in 2022 due to warming. This could potentially lead to N deficiencies in spring and summer, thus limiting the availability of N to phytoplankton. A TN concentration of less than 1.0 mg L-1 in the lake and 1.5 mg L-1 in the inflowing lake zones in spring contribute to local N-limitation in Lake Taihu for cyanobacteria control. Our study revealed a general pattern that N removal efficiency decreases with improved water quality, which is instructive for eutrophic lakes in nitrogen management.
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Affiliation(s)
- Lijuan Kang
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Mengyuan Zhu
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, PR China
| | - Guangwei Zhu
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China.
| | - Hai Xu
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, PR China
| | - Wei Zou
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, PR China
| | - Man Xiao
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, PR China
| | - Chaoxuan Guo
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, PR China
| | - Yunlin Zhang
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, PR China
| | - Boqiang Qin
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, PR China
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Zhang X, Zhao Y, Wang Y, Qian H, Xing J, Joseph A, Rene ER, Li J, Zhu N. The interplay of hematite and photic biofilm triggers the acceleration of biotic nitrate removal. CHEMOSPHERE 2024; 358:142136. [PMID: 38692363 DOI: 10.1016/j.chemosphere.2024.142136] [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: 02/05/2024] [Revised: 04/22/2024] [Accepted: 04/23/2024] [Indexed: 05/03/2024]
Abstract
The soil-water interface is replete with photic biofilm and iron minerals; however, the potential of how iron minerals promote biotic nitrate removal is still unknown. This study investigates the physiological and ecological responses of photic biofilm to hematite (Fe2O3), in order to explore a practically feasible approach for in-situ nitrate removal. The nitrate removal by photic biofilm was significantly higher in the presence of Fe2O3 (92.5%) compared to the control (82.8%). Results show that the presence of Fe2O3 changed the microbial community composition of the photic biofilm, facilitates the thriving of Magnetospirillum and Pseudomonas, and promotes the growth of photic biofilm represented by the extracellular polymeric substance (EPS) and the content of chlorophyll. The presence of Fe2O3 also induces oxidative stress (•O2-) in the photic biofilm, which was demonstrated by electron spin resonance spectrometry. However, the photic biofilm could improve the EPS productivity to prevent the entrance of Fe2O3 to cells in the biofilm matrix and mitigate oxidative stress. The Fe2O3 then promoted the relative abundance of Magnetospirillum and Pseudomonas and the activity of nitrate reductase, which accelerates nitrate reduction by the photic biofilm. This study provides an insight into the interaction between iron minerals and photic biofilm and demonstrates the possibility of combining biotic and abiotic methods to improve the in-situ nitrate removal rate.
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Affiliation(s)
- Xiguo Zhang
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lake of Ministry of Education, College of Environment, Hohai University, Nanjing, 210098, China
| | - Yanhui Zhao
- Changjiang Basin Ecology and Environment Monitoring and Scientific Research Center, Changjiang Basin Ecology and Environment Administration, Ministry of Ecology and Environment, Wuhan, 430010, China
| | - Yimin Wang
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lake of Ministry of Education, College of Environment, Hohai University, Nanjing, 210098, China
| | - Haoliang Qian
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lake of Ministry of Education, College of Environment, Hohai University, Nanjing, 210098, China
| | - Jun Xing
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lake of Ministry of Education, College of Environment, Hohai University, Nanjing, 210098, China
| | - Akaninyene Joseph
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lake of Ministry of Education, College of Environment, Hohai University, Nanjing, 210098, China
| | - Eldon R Rene
- Department of Water Supply, Sanitation and Environmental Engineering, IHE Delft Institute for Water Education, Westvest 7, 2611AX, Delft, the Netherlands
| | - Jizhou Li
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lake of Ministry of Education, College of Environment, Hohai University, Nanjing, 210098, China
| | - Ningyuan Zhu
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lake of Ministry of Education, College of Environment, Hohai University, Nanjing, 210098, China; Institute of Soil Sciences, Chinese Academy of Sciences, 71 East Beijing Road, 210008, China.
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Dong R, Peng K, Zhang Q, Heino J, Cai Y, Gong Z. Spatial and temporal variation in lake macroinvertebrate communities is decreased by eutrophication. ENVIRONMENTAL RESEARCH 2024; 243:117872. [PMID: 38086502 DOI: 10.1016/j.envres.2023.117872] [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: 10/13/2023] [Revised: 11/15/2023] [Accepted: 12/03/2023] [Indexed: 12/17/2023]
Abstract
Eutrophication impacts freshwater ecosystems and biodiversity across the world. While temporal monitoring has shown changes in the nutrient inputs in many areas, how spatial and temporal beta diversity change along the eutrophication gradient under a changing context remains unclear. In this regard, analyses based on time series spanning multiple years are particularly scarce. We sampled benthic macroinvertebrates in 32 sites across three lake habitat types (MACROPHYTE, OPEN WATER, PHYTOPLANKTON) along the eutrophication gradient of Lake Taihu in four seasons from 2007 to 2019. Our purpose was to identify the relative contributions of spatial and temporal dissimilarity (i.e., inter-annual dissimilarity and seasonal dissimilarity) to overall benthic biodiversity. We also examined spatio-temporal patterns in community assembly mechanisms and how associated variation in benthic macroinvertebrate communities responded to nutrient indicators. Results showed that eutrophication caused macroinvertebrate community homogenization both along spatial and temporal gradients. Though spatial variability dominated the variation of species richness, abundance and community dissimilarity, seasons within years dissimilarity, inter-annual dissimilarity and seasonal dissimilarity were much more sensitive to eutrophication. Moreover, eutrophication inhibited a strong environmental control in benthic macroinvertebrate community assembly, including a dominant role of deterministic process in the spatial variation of macroinvertebrate communities and transition from stochastic to deterministic process in the temporal assembly of macroinvertebrate communities along the eutrophication gradient. In addition, some sites in PHYTOPLANKTON habitats showed similar spatial dissimilarity and spatial SES as sites in MACROPHYTE habitats, and the decreased spatial dissimilarity of three habitats implying that lake ecosystem recovery projects have achieved their goal at least to a certain degree.
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Affiliation(s)
- Rui Dong
- Key Laboratory of Watershed Geographic Sciences, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, PR China; University of Chinese Academy of Sciences, Beijing, PR China
| | - Kai Peng
- Key Laboratory of Watershed Geographic Sciences, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, PR China
| | - Qingji Zhang
- School of Geography and Ocean Science, Nanjing University, Nanjing, PR China
| | - Jani Heino
- Geography Research Unit, University of Oulu, P.O. Box 8000, FI-90014, Oulu, Finland
| | - Yongjiu Cai
- Key Laboratory of Watershed Geographic Sciences, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, PR China; University of Chinese Academy of Sciences, Beijing, PR China.
| | - Zhijun Gong
- Key Laboratory of Watershed Geographic Sciences, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, PR China; University of Chinese Academy of Sciences, Beijing, PR China.
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Zhang Q, Guo X, Zhao T, Jin C, Xiao C, He Y. Atmospheric organic nitrogen deposition around the Danjiangkou Reservoir: Fluxes, characteristics and evidence of agricultural source. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 341:122906. [PMID: 37952919 DOI: 10.1016/j.envpol.2023.122906] [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: 08/16/2023] [Revised: 10/19/2023] [Accepted: 11/08/2023] [Indexed: 11/14/2023]
Abstract
Dissolved organic nitrogen (DON) deposition was the substantial component of dissolved total nitrogen (DTN) deposition in the world's nitrogen deposition hot spots areas. However, the information on the importance for DON deposition and its sources was still scarce, which limited the comprehensive assessment of the ecological threat from nitrogen deposition. Six sampling sites around the Danjiangkou Reservoir were set up to collect the dry and wet deposition samples from October 2017 to September 2021. The results showed that dry and wet DTN deposition averaged 34.72 kg ha-1 yr-1 and 22.27 kg ha-1 yr-1, respectively. Dry NH4+-N, NO3--N and DON deposition averaged 14.28 kg ha-1 yr-1, 5.91 kg ha-1 yr-1 and 14.53 kg ha-1 yr-1, respectively. Wet NH4+-N, NO3--N and DON deposition averaged 11.14 kg ha-1 yr-1, 3.89 kg ha-1 yr-1and 7.24 kg ha-1 yr-1, respectively. The contributions of DON to DTN were 41.85% (in dry deposition) and 32.50% (in wet deposition), respectively. Dry DON deposition varied between 26.44 kg ha-1 yr-1 and 9.11 kg ha-1 yr-1, and significantly differed among six sampling sites (P < 0.05). The different intensity of agricultural activities disturbance at the sampling sites was the important reason for the spatial variations of DON deposition. DON deposition was significantly correlated with ammonium nitrogen (NH4+-N) deposition (P < 0.05). According to the results of positive matrix factorization (PMF) model, agriculture source contributed significantly to the DON deposition, the contributions at six sampling sites ranged from 45.8% to 73.7% in dry deposition, and from 56.8% to 81.6% in wet deposition. In summary, our findings found that agricultural activities were the important factors influencing the spatial patterns of DON deposition around Danjiangkou Reservoir and provided new evidence for the anthropogenic source of DON deposition in China.
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Affiliation(s)
- Qingmiao Zhang
- Institute of Resources & Environment, Henan Polytechnic University, Jiaozuo, 454003, China
| | - Xiaoming Guo
- Institute of Resources & Environment, Henan Polytechnic University, Jiaozuo, 454003, China.
| | - Tongqian Zhao
- Institute of Resources & Environment, Henan Polytechnic University, Jiaozuo, 454003, China
| | - Chao Jin
- Institute of Resources & Environment, Henan Polytechnic University, Jiaozuo, 454003, China
| | - Chunyan Xiao
- Institute of Resources & Environment, Henan Polytechnic University, Jiaozuo, 454003, China
| | - Yuxiao He
- Institute of Resources & Environment, Henan Polytechnic University, Jiaozuo, 454003, China
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