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	Temporal controls on dissolved organic carbon biodegradation in subtropical rivers: Initial chemical composition versus stoichiometry
	Mao, Rong1,2; Li, Siyue1
	2019-02-15
摘要	Dissolved organic carbon (DOC) plays an indispensable role in biogeochemical cycles and ecosystem services in rivers. However, little is known about the seasonal variations of DOC biodegradation in subtropical rivers. Here, we investigated the concentrations of DOC, dissolved total nitrogen ( DIN), and dissolved total phosphorus (DTP), humikation index (HIX), fluorescence index (FI), and DOC biodegradation in 57 rivers in the dry and wet seasons in the Three Gorges Reservoir area, China, and the aims were to clarify the temporal changes in DOC biodegradation and its driving factors in these subtropical rivers. Compared with dry season, DIN and DTP concentrations, and HIX value were greater, and Fl value was lower in the wet season. However, DOC biodegradation remained unchanged across the two sampling seasons. Further, DOC biodegradation negatively correlated with DOC:DTP ratio, DTN:DTP ratio, and Fl in the dry season, but only with HIX in the wet season. These findings emphasis that, despite unchanged DOC biodegradation, the key factors driving DOC biodegradation shift from C:N:P stoichiometry in the dry season to initial chemical composition in the wet season in subtropical rivers. Our results regarding the temporal patterns of DOC biodegradation and the underlying mechanisms bear important implications for a better understanding of C dynamics in subtropical river ecosystems. (C) 2018 Elsevier B.V. All rights reserved.
关键词	Biodegradability Carbon dioxide production Nutrient availability Riverine C cycle The Three Gorges Reservoir area
DOI	10.1016/j.scitotenv.2018.10.220
发表期刊	SCIENCE OF THE TOTAL ENVIRONMENT
ISSN	0048-9697
卷号	651页码:3064-3069
收录类别	SCI
WOS记录号	WOS:000450551600131
语种	英语