Natural and human influences on dissolved silica export from watershed to coast in Southeast China

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	Natural and human influences on dissolved silica export from watershed to coast in Southeast China
	Chen, Nengwang ; Wu, Yinqi ; Wu, Jiezhong ; Yan, Xiuli ; Hong, Huasheng ; Chen NW(陈能汪) ; Hong HS(洪华生)
刊名	http://dx.doi.org/10.1002/2013JG002429
	2014
关键词	WEATHERING RATES HYDROLOGICAL ALTERATIONS BIOGENIC SILICA YANGTZE-RIVER EAST CHINA BALTIC SEA RETENTION CYCLE EUTROPHICATION RESERVOIRS
英文摘要	National Natural Science Foundation of China [41076042, 41376082]; Fundamental Research Funds for the Central Universities [2012121053]; Science Foundation of Fujian Province [2010Y0064]; Natural and human factors controlling dissolved silica (DSi) export from the watershed were investigated for the Jiulong River watershed in Southeast China, which is a subtropical region where tectonic activity and high runoff combine to create a global hot spot for DSi flux. Results showed that river DSi was fairly high (24676 mu mol L-1) due to granite lithology and increased human perturbation. The percentage of granite, paddy soil, arable land, and forest land each explain 47-69% of the spatial variation in DSi level at the subwatershed scale. Land use change (deforestation for agriculture) and soil erosion increased DSi transfer from terrestrial systems towards the river. Discharge explains over 95% of the variation in DSi fluxes, and a discrepancy of up to 16% of watershed DSi export was observed between low and high flow conditions. DSi retention is more significant in the dry season, likely due to biological uptake by diatoms in reservoirs under low flow conditions and higher residence time. However, this may be offset by high runoff flush in the wet season, which might cause unfavorable conditions for diatom growth and DSi depletion. There has been little overall change in DSi in estuarine water in recent decades. However, seasonal variation and occasionally fluctuation of DSi during extreme hydrological events (rainstorms) does exist, with important implications for the coastal ecosystem. This research confirmed that human activities and land use change have substantially altered Si delivery, cycling and riverine export to the coast in this region. Key Points Land use/cover change explain most of stream DSi variation 16% reduction of DSi fluxes due to damming but offset by high runoff Human have altered riverine DSi delivery, cycling and seaward export
语种	英语
出版者	AMER GEOPHYSICAL UNION
内容类型	期刊论文
源URL	[http://dspace.xmu.edu.cn/handle/2288/89944]
专题	环境生态－已发表论文
推荐引用方式 GB/T 7714	Chen, Nengwang,Wu, Yinqi,Wu, Jiezhong,et al. Natural and human influences on dissolved silica export from watershed to coast in Southeast China[J]. http://dx.doi.org/10.1002/2013JG002429,2014.
APA	Chen, Nengwang.,Wu, Yinqi.,Wu, Jiezhong.,Yan, Xiuli.,Hong, Huasheng.,...&洪华生.(2014).Natural and human influences on dissolved silica export from watershed to coast in Southeast China.http://dx.doi.org/10.1002/2013JG002429.
MLA	Chen, Nengwang,et al."Natural and human influences on dissolved silica export from watershed to coast in Southeast China".http://dx.doi.org/10.1002/2013JG002429 (2014).