Seasonal variations in the nitrogen isotopic composition of dissolved nitrate in the Changjiang River estuary, China

CORC > 海洋研究所 > 中国科学院海洋研究所 > 海洋生态与环境科学重点实验室

	Seasonal variations in the nitrogen isotopic composition of dissolved nitrate in the Changjiang River estuary, China
	Yu, Haiyan; Yu, Zhiming; Song, Xiuxian; Cao, Xihua; Yuan, Yongquan; Lu, Guangyuan
刊名	ESTUARINE COASTAL AND SHELF SCIENCE
	2015-03-20
卷号	155 页码:148-155
关键词	nitrogen isotopes nitrification mineralization assimilation eutrophication
英文摘要	The Changjiang River estuary is the most eutrophic estuary in China. Although anthropogenic input from the Changjiang River (the third-largest river in the world) is considered the main source of nitrogen, the contributions of newly regenerated nitrogen from deep waters may be underestimated, in part due to the lack of information on the nitrogen biogeochemical processes that are occurring. The nitrogen stable isotope ratio is widely used as an indicator of the source of nitrogen and nitrogen transformation processes including assimilation, nitrification, nitrogen fixation and mineralization. To study the biogeochemical processes in the Changjiang River estuary, seasonal variations in the nitrogen stable isotope ratio of nitrate (delta(NO3)-N-15), salinity, temperature, dissolved oxygen concentration, chlorophyll a (Chl a) concentration, and the composition of dissolved inorganic nitrogen were investigated along two transects in the estuary in 2010. In the surface waters, assimilation between May and November was suggested by high Chl a and delta(NO3)-N-15 and supported by the mixing behavior of the nitrate and delta(NO3)-N-15. From February to November, the mean nitrate content in the deep waters gradually increased (from similar to 8 to similar to 15 mu mol l(-1)), whereas the mean delta(NO3)-N-15 decreased (from similar to 2 parts per thousand to similar to-2 parts per thousand). Particularly in November, most of the delta(NO3)-N-15 values in the deep waters were negative (similar to-5 parts per thousand -0 parts per thousand, which is much lower than the similar to 3 parts per thousand riverine input from delta(NO3)-N-15), indicating that most of the nitrates in the deep water were newly regenerated from nitrification rather than originating from riverine input Additionally, the mean ammonium abruptly increased (from similar to 2 to similar to 20 mu mol l(-1)) in the deep waters during November when the delta(NO3)-N-15 values were negative, whereas in August, high Chl a values were observed in the deep waters. These results indicate that remineralization and nitrification occurred in the deep waters of the Changjiang River estuary, implying that regenerated nitrogen may also be an important nitrogen source for uptake by phytoplankton. (C) 2015 Elsevier Ltd. All rights reserved.
收录类别	SCI
语种	英语
WOS记录号	WOS:000352675600016
公开日期	2015-06-16
内容类型	期刊论文
源URL	[http://ir.qdio.ac.cn/handle/337002/25450]
专题	海洋研究所_海洋生态与环境科学重点实验室
作者单位	Chinese Acad Sci, Inst Oceanol, Key Lab Marine Ecol & Environm Sci, Qingdao 266071, Peoples R China
推荐引用方式 GB/T 7714	Yu, Haiyan,Yu, Zhiming,Song, Xiuxian,et al. Seasonal variations in the nitrogen isotopic composition of dissolved nitrate in the Changjiang River estuary, China[J]. ESTUARINE COASTAL AND SHELF SCIENCE,2015,155:148-155.
APA	Yu, Haiyan,Yu, Zhiming,Song, Xiuxian,Cao, Xihua,Yuan, Yongquan,&Lu, Guangyuan.(2015).Seasonal variations in the nitrogen isotopic composition of dissolved nitrate in the Changjiang River estuary, China.ESTUARINE COASTAL AND SHELF SCIENCE,155,148-155.
MLA	Yu, Haiyan,et al."Seasonal variations in the nitrogen isotopic composition of dissolved nitrate in the Changjiang River estuary, China".ESTUARINE COASTAL AND SHELF SCIENCE 155(2015):148-155.