Interpretation of the environmental change of Dongting Lake, middle reach of Yangtze River, China, by 210Pb measurement and satellite image analysis
Interpretation of the environmental change of Dongting Lake, middle reach of Yangtze River, China, by 210Pb measurement and satellite image analysis
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DOI：
10.1016/s0169-555x(01)00114-3
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发表时间：
2001-11-15
期刊：
影响因子：
3.9
通讯作者：
Zhao, Y
中科院分区：
文献类型：
--
作者：
Du, Y;Cai, SM;Zhao, Y
本文研究了位于长江中游地区、中国中部的洞庭湖的近代环境历史。沉积物由不同湖段的22个震源岩心回收，主要表现为水下三角洲和海湾亚相。铅-210测量表明，该湖不同亚相的沉积速率较高，为0.77~2.33 cm/年。这些速率相当于与长江洪水事件导致的活动河道有关的三角洲沉积。卫星图像证实，洞庭湖没有发生长江上最大的洪水。此外，对比水深测量证实，在过去的一个世纪里，洞庭湖失去了近三分之二的总面积，这主要是由于长江泥沙的淤积。19世纪末，一次大规模的洪水引发的河道撕裂导致四支支流次流域与洞庭湖的耦合，导致自那时以来对洞庭湖的泥沙供应大量增加。水文资料表明，该湖年来沙量的83%来自长江。此外，来自不断增长的人口和相关人类活动的压力，如开垦、堤防、水产养殖、坡度改良和砍伐森林，正在加剧湖泊表面积和相关储存能力的损失。(C)2001 Elsevier Science B.V.保留所有权利。
The present study examined the recent environmental history of the Dongting Lake, located in the middle Yangtze River region, central China. The sediment was recovered by 22 vibrocores in different lake sectors, primarily characterizing subaqueous delta and bay subfacies. High sedimentation rates, revealed by Pb-210 measurement in different subfacies of the lake, ranged from 0.77 to 2.33 cm/year. These rates equate to deltaic sedimentation associated with mobile channels resulting from Yangtze flood events. Satellite images confirm that the Dongting Lake does not contain the biggest Yangtze floods. Moreover, comparative bathymetric surveys verify that the Dongting Lake has lost almost two-thirds of its total area in the past century, due primarily to siltation by Yangtze sediment. In the late 19th century, a major flood-induced channel avulsion resulted in the coupling of the 'Four-Tributary' subbasin to the Dongting Lake, causing a massive increase in the sediment supply into the lake since then. Hydrological data demonstrate that about 83% of the lake's annual sediment influx are derived from the Yangtze. In addition, pressures from a growing population and associated human activities, such as reclamation, embanking, aquaculture, slope modification and deforestation, are compounding the loss of the lake surface area and associated storage capacity. (C) 2001 Elsevier Science B.V. All rights reserved.