干旱区生态环境知识资源中心(Arid): Ecological Degradation of the Yangtze and Nile Delta-Estuaries in Response to Dam Construction with Special Reference to Monsoonal and Arid Climate Settings

Arid

DOI	10.3390/w13091145
	Ecological Degradation of the Yangtze and Nile Delta-Estuaries in Response to Dam Construction with Special Reference to Monsoonal and Arid Climate Settings
	Chen, Zhongyuan; Xu, Hao; Wang, Yanna
通讯作者	Chen, ZY (corresponding author), East China Normal Univ, State Key Lab Estuarine & Coastal Res, Shanghai 200062, Peoples R China.
来源期刊	WATER
EISSN	2073-4441
出版年	2021
卷号	13 期号:9
英文摘要	This study reviews the monsoonal Yangtze and the arid Nile deltas with the objective of understanding how the process-response between river-basin modifications and delta-estuary ecological degradation are interrelated under contrasting hydroclimate dynamics. Our analysis shows that the Yangtze River had a long-term stepwise reduction in sediment and silicate fluxes to estuary due to dam construction since the 1960s, especially after the Three Gorges Dam (TGD) closed in 2003. By contrast, the Nile had a drastic reduction of sediment, freshwater, and silicate fluxes immediately after the construction of the Aswan High Dam (AHD) in 1964. Seasonal rainfall in the mid-lower Yangtze basin (below TGD) complemented riverine materials to its estuary, but little was available to the Nile coast below the AHD in the hyper-arid climate setting. Nitrogen (N) and phosphate (P) fluxes in both river basins have increased because of the overuse of N- and P-fertilizer, land-use changes, urbanization, and industrialization. Nutrient ratios (N:P:Si) in both delta-estuaries was greatly altered, i.e., Yangtze case: 75:1:946 (1960s-1970s), 86:1:272 (1980s-1990s) and 102:1:75 (2000s-2010s); and Nile case: 6:1:32 (1960s-1970s), 8:1:9 (1980s-1990s), and 45:1:22 (2013), in the context of the optimum of Redfield ratio (N:P:Si = 16:1:16). This led to an ecological regime shift evidenced by a long-term change in phytoplankton communities in the Yangtze estuary, where silicious algae tended to lose dominance since the end of the 1990s, when more toxic dinoflagellates began to emerge. In the Nile estuary, such a regime shift was indicated by the post-dam dramatic reduction in zooplankton standing crop and fish landings until the early 2000s when biological recovery occurred due to nutrient inputs from anthropogenic sources. Although the Yangtze had higher human impacts than the Nile in terms of population, industrialization, and fertilizer application, N concentrations in the Nile estuarine waters surpassed the Yangtze in recent decades. However, eutrophication in the Yangtze estuary is much more intensive than in the Nile, leading to the likelihood of its estuarine water becoming more acidic than ever before. Therefore, ecological degradation in both delta-estuaries does not follow a linear trajectory, due not only to different climate dynamics but also to human forcings. The comparative insights of this study should be incorporated into future integrated coastal management of these two important systems.
英文关键词	altered nutrient ratio riverine flux bio-transformation river-basin-scale post-dam consequences
类型	Review
语种	英语
开放获取类型	gold
收录类别	SCI-E
WOS记录号	WOS:000650862900001
WOS关键词	3 GORGES DAM ; PHYTOPLANKTON COMMUNITY ; CHANGJIANG RIVER ; CHINA ; NITROGEN ; SEA ; EUTROPHICATION ; SEDIMENT ; IMPACTS ; FLUX
WOS类目	Environmental Sciences ; Water Resources
WOS研究方向	Environmental Sciences & Ecology ; Water Resources
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/368808
作者单位	[Chen, Zhongyuan; Wang, Yanna] East China Normal Univ, State Key Lab Estuarine & Coastal Res, Shanghai 200062, Peoples R China; [Xu, Hao] Ningbo Univ, Dept Geog & Spatial Informat Tech, Ningbo 315211, Peoples R China
推荐引用方式 GB/T 7714	Chen, Zhongyuan,Xu, Hao,Wang, Yanna. Ecological Degradation of the Yangtze and Nile Delta-Estuaries in Response to Dam Construction with Special Reference to Monsoonal and Arid Climate Settings[J],2021,13(9).
APA	Chen, Zhongyuan,Xu, Hao,&Wang, Yanna.(2021).Ecological Degradation of the Yangtze and Nile Delta-Estuaries in Response to Dam Construction with Special Reference to Monsoonal and Arid Climate Settings.WATER,13(9).
MLA	Chen, Zhongyuan,et al."Ecological Degradation of the Yangtze and Nile Delta-Estuaries in Response to Dam Construction with Special Reference to Monsoonal and Arid Climate Settings".WATER 13.9(2021).