Spatio-Temporal Differences in Nitrogen Reduction Rates under Biotic and Abiotic Processes in River Water of the Taihu Basin, China

Jiaxun Guo, Lachun Wang, Xiya Guo, Gengmao Zhao, Jiancai Deng and Chunfen Zeng
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Jiaxun Guo: School of Geographic and Oceanographic Sciences, Nanjing University, Nanjing 210023, China
Lachun Wang: School of Geographic and Oceanographic Sciences, Nanjing University, Nanjing 210023, China
Xiya Guo: Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China
Gengmao Zhao: College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China
Jiancai Deng: Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China
Chunfen Zeng: School of Geographic and Oceanographic Sciences, Nanjing University, Nanjing 210023, China

IJERPH, 2018, vol. 15, issue 11, 1-17

Abstract: Understanding spatio-temporal differences in nitrogen (N) transformation, transport and reduction rates in water bodies is critical to achieve effective mitigation of river eutrophication. We performed culture experiments in six rivers in the Taihu Basin using a custom made in-situ experimental apparatus. We investigated spatio-temporal differences in reduce processes and rates of different N forms and assessed the contribution of biological processes to dissolved inorganic N (DIN) reduce. Results showed that biological processes played a major role in N reduction in summer, while non-microbial processes were dominant in winter. We observed significant spatial and temporal differences in the studied mechanisms, with reduction rates of different N compounds being significantly higher in summer and autumn than spring and winter. Reduction rates ranged from 105.4 ± 25.3 to 1458.8 ± 98.4 mg·(m 3 ·d) −1 for total N, 33.1 ± 12.3 to 440.9 ± 33.1 mg·(m 3 ·d) −1 for ammonium, 56.3 ± 22.7 to 332.1 ± 61.9 mg·(m 3 ·d) −1 for nitrate and 0.4 ± 0.3 to 31.8 ± 9.0 mg·(m 3 ·d) −1 for nitrite across four seasons. Mean DIN reduction rates with and without microbial activity were 96.0 ± 46.4 mg·(m 3 ·d) −1 and 288.1 ± 67.8 mg·(m 3 ·d) −1 , respectively, with microbial activity rates accounting for 29.7% of the DIN load and 2.2% of the N load. Results of correlation and principal component analysis showed that the main factors influencing N processing were the concentrations of different N forms and multiple environmental factors in spring, N concentrations, DO and pH in summer, N concentrations and water velocity in autumn and N concentrations in winter.

Keywords: nitrogen reduce; spatio-temporal differences; biotic and abiotic; in-situ; Taihu Basin (search for similar items in EconPapers)
JEL-codes: I I1 I3 Q Q5 (search for similar items in EconPapers)
Date: 2018
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (1)

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