Dissimilatory nitrate/nitrite reduction processes in river sediments across climatic gradient : influences of biogeochemical controls and climatic temperature regime
Li, Xiaofei (Fujian Normal University. Key Laboratory for Humid Subtropical Eco-geographical Processes of the Ministry of Education)
Sardans i Galobart, Jordi (Centre de Recerca Ecològica i d'Aplicacions Forestals)
Hou, Lijun (East China Normal University. State Key Laboratory of Estuarine and Costal Research)
Gao, Dengzhou (East China Normal University. School of Geographic Sciences)
Liu, Min (East China Normal University. School of Geographic Sciences)
Peñuelas, Josep (Centre de Recerca Ecològica i d'Aplicacions Forestals)

Date:	2019
Abstract:	Dissimilatory nitrate/nitrite reduction processes play an important role in controlling nitrogen loading in river environments. However, the relative importance of climatic temperature regime and biogeochemical controls to dissimilatory nitrate/nitrite reduction processes remains unclear. We used nitrogen isotope tracer approach to investigate geographical variabilities of denitrification, anaerobic ammonium oxidation (anammox), and dissimilatory nitrate reduction to ammonium (DNRA) in river sediments from temperate to tropical climates of China. Denitrification, anammox, and DNRA varied greatly across the climatic gradient, with potential rates of 1. 47-25. 7, 0. 54-3. 4, and 0. 15-7. 17 nmol N g⁻¹ h⁻¹, respectively. Mean measured rates throughout the sampling sites were 9. 73 nmol N g⁻¹1 h⁻¹ for denitrification, 1. 29 nmol N g⁻¹ h⁻¹ for anammox, and 1. 61 nmol N g⁻¹ h⁻¹ for DNRA. Denitrification and DNRA rates increased significantly from temperate to tropical climates, while no significantly spatial difference was observed for anammox rates along the climatic gradient. Mean annual temperature, total organic carbon, dissolved organic carbon, pH, NH₄+, NO₃-, C/N, Fe²+, and functional genes were the crucial factors affecting denitrification, anammox, and DNRA. High dissolved organic carbon and NO₃- availability determined nitrogen removal capacity in river sediments. Mean annual temperature was the most important factor explaining the geographical variances of denitrification and DNRA, while the critical predictor of anammox variance was sediment pH along the climatic gradient. Our results highlight that biogeochemical controls and climatic temperature regime are important coregulators affecting the geographical variabilities of dissimilatory nitrate/nitrite reduction processes in river sediments at the continental-scale variation.
Grants:	European Commission 610028 Ministerio de Economía y Competitividad CGL2016-79835 Agència de Gestió d'Ajuts Universitaris i de Recerca 2017/SGR-1005
Note:	imbalance-p paper contact with j.sardans@creaf.uab.cat
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Language:	Anglès
Document:	Article ; recerca ; Versió publicada
Subject:	Nitrate/nitrite reduction ; Biogeochemical controls ; Climatic gradient ; Geographical variability
Published in:	Journal of geophysical research. Biogeosciences, Vol. 124, issue 7 (July 2019) , p. 2305-2320, ISSN 2169-8961

DOI: 10.1029/2019JG005045

16 p, 1.8 MB

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