کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5751680 | 1619703 | 2017 | 8 صفحه PDF | دانلود رایگان |
- The nitrogen concentrations showed significant spatio-temporal variations.
- Terrigenous inputs by rain runoff led to peaked values of δ15N in nitrate and SPN.
- Nitrate and SPN in water derived from atmospheric deposition, fertilizers and sewage
There are increasing concerns in nitrogen (N) pollution worldwide, especially in aquatic ecosystems, and thus quantifying its sources in waterways is critical for pollution prevention and control. In this study, we investigated the spatio-temporal variabilities of inorganic N concentration (i.e., NO3â, NH4+) and total dissolved N (TDN) and identified their sources in waters and suspended matters using an isotopical approach in the Jinshui River, a river with a length of 87 km in the monsoon-climate region of China. The spatio-temporal inorganic N concentrations differed significantly along the longitudinal gradient in the river network. The NO3â, NH4+ and TDN concentrations ranged from 0.02 to 1.12 mg lâ 1, 0.03 to 4.28 mg lâ 1, and 0.33 to 2.78 mg lâ 1, respectively. The 15N tracing studies demonstrated that N in suspended organic matter was in the form of suspended particulate nitrogen (SPN) and was primarily from atmospheric deposition and agricultural fertilizer. In contrast, N in stream waters was mainly in the form of nitrate and was from atmospheric deposition, fertilizers, soil, and sewage. Meanwhile, both δ15N-SPN and δ15N-NO3â peaked in the rainy season (i.e., July) because of higher terrigenous sources via rain runoff, demonstrating the dominant diffusive N sources in the catchment. Thus, our results could provide critical information on N pollution control and sustainable watershed management of the riverine ecosystem in monsoon-climate region.
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Journal: Science of The Total Environment - Volume 592, 15 August 2017, Pages 608-615