Recent changes of sediment flux to the western Pacific Ocean from major rivers in East and Southeast Asia
Recent changes of sediment flux to the western Pacific Ocean from major rivers in East and Southeast Asia
复制标题
东亚和东南亚主要河流向西太平洋沉积物通量的近期变化
DOI：
10.1016/j.earscirev.2011.06.003
复制
发表时间：
2011-09-01
影响因子：
12.1
通讯作者：
Yang, Zuosheng
中科院分区：
文献类型：
--
作者：
Wang, Houjie;Saito, Yoshiki;Yang, Zuosheng
东亚和东南亚最大的五条河流(黄河、长江、珍珠、红河和湄公河)是西太平洋陆源沉积物的重要贡献者。尽管自1000年以来，它们每年向海洋输送的沉积物约为2000×10(9)公斤，但目前它们对海洋的贡献仅为600×10(9)公斤/年，这正在恢复到东亚和东南亚人类活动在2000年BP上升之前相对未受干扰的流域的典型水平。近几十年来，水坝的调流和水库的泥沙截留，以及人为影响的流域土壤侵蚀，大大减少了从大流域向海洋输送的泥沙。我们构建了1950-2008年期间从这些大河到西太平洋的年排水量和泥沙通量的时间序列。这些数据表明，泥沙通量的短期(年际)变化是由厄尔尼诺/拉尼娜循环等自然气候振荡所主导的，而涉及大坝和土地利用的人为原因控制了进入海洋的泥沙通量的长期(十年尺度)减少。与2000年至1000a BP期间沉积物通量历史上相对缓慢的增长相反，现代沉积物通量在百年尺度上以加速的速度减少。由于自然和人为的强迫，这些大型水系的改变给沿海海洋带来了严峻的环境挑战，包括三角洲的下沉和沿海湿地地区由于沉积物供应的减少而下降。因此，我们的工作提供了一个关于千年和十年尺度上大量河流来源的沉积物向海洋输送的区域视角，这对于在全球变化的背景下理解和管理目前和未来陆源沉积物向海洋输送的趋势将是重要的。(C)2011爱思唯尔B.V.保留所有权利。
The five largest rivers in East and Southeast Asia (Yellow, Yangtze, Pearl, Red and Mekong) are important contributors of terrigenous sediment to the western Pacific Ocean. Although they have annually delivered similar to 2000 x 10(9) kg of sediment to the ocean since 1000 yr BP, they presently contribute only similar to 600 x 10(9) kg/yr, which is reverting to a level typical of the relatively undisturbed watersheds before the rise in human activities in East and Southeast Asia at 2000 yr BP. During the most recent decades flow regulation by dams and sediment entrapment by reservoirs, as well as human-influenced soil erosion in the river basins, have sharply reduced the sediment delivered from the large river basins to the ocean. We constructed a time series of data on annual water discharges and sediment fluxes from these large rivers to the western Pacific Ocean covering the period 1950-2008. These data indicate that the short-term (interannual scale) variation of sediment flux is dominated by natural climatic oscillations such as the El Nino/La Nina cycle and that anthropogenic causes involving dams and land use control the long-term (decadal scale) decrease in sediment flux to the ocean. In contrast to the relatively slow historical increase in sediment flux during the period 2000-1000 yr BP, the recent sediment flux has been decreased at an accelerating rate over centennial scales. The alterations of these large river systems by both natural and anthropogenic forcing present severe environmental challenges in the coastal ocean, including the sinking of deltas and declines in coastal wetland areas due to the decreasing sediment supply. Our work thus provides a regional perspective on the large river-derived sediment flux to the ocean over millennial and decadal scales, which will be important for understanding and managing the present and future trends of delivery of terrigenous sediment to the ocean in the context of global change. (C) 2011 Elsevier B.V. All rights reserved.