| 近30年长江口北支演变及其对物种多样性的影响 |
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| 引用本文： | 吴逢润,童春富.近30年长江口北支演变及其对物种多样性的影响[J].海洋学报,2017,39(2):72-85. |
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| 作者姓名： | 吴逢润 童春富 |
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| 作者单位： | 华东师范大学 河口海岸学国家重点实验室, 上海 200062 |
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| 基金项目： | 上海市科委自然科学基金（15ZR1411200）；教育部留学回国人员科研启动基金。 |
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| 摘 要： | 分汊河口演变特征及其生态效应是当前河口海岸研究的重要热点问题。长江口北支是长江口第一级分汊的重要水道，其演变会对区域生态与环境条件产生深远的影响。本文在已有研究结果基础上，结合遥感影像分析与水域生态现状调研，阐述了近30年来长江口北支河道的演变特征和生态现状，并对河道演变对物种多样性的影响进行了深入的探讨。结果表明，近30年来北支演变的突出特点在于北支中上段束窄明显，而下段河道虽然有一定程度的束窄，但口门仍呈喇叭口形态；大量的圈围工程是导致北支中上段河道束窄的最重要因素；随着河势变化，北支分流比下降，分沙比上升，河道水深、河槽容积的下降，使北支盐水入侵加剧，水、沙、盐倒灌南支的风险增加。北支演变导致水体盐度条件的改变，使得区域生物类群以适应高盐、咸淡水环境的种类为主；而河道水深、水动力条件、水体含沙量等的变化均会对生物类群的组成产生影响。北支目前仍然是大型底栖动物、鱼类等生物类群的重要栖息地和育幼场，且具有较高的生物多样性。因此，北支治理仍需考虑维持北支水域生态系统的结构与功能不被破坏，确保区域的可持续发展。未来北支的演变趋势及其生态效应，需要在有效监测的基础上进行综合分析。
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| 关 键 词： | 长江口 北支演变 物种多样性 |
| 收稿时间： | 2016/6/20 0:00:00 |
| 修稿时间： | 2016/10/9 0:00:00 |
Evolution of the North Branch of Yangtze Estuary in last 30 years and corresponding effects on species diversity |
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| Wu Fengrun and Tong Chunfu.Evolution of the North Branch of Yangtze Estuary in last 30 years and corresponding effects on species diversity[J].Acta Oceanologica Sinica (in Chinese),2017,39(2):72-85. |
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| Authors: | Wu Fengrun and Tong Chunfu |
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| Institution: | State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200062, China |
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| Abstract: | The evolution characteristics of the anabranched estuary and their ecological effects are important issues of current estuarine and coastal research. The North Branch is one of the first order bifurcations of Yangtze Estuary. Its evolution would have profound effects on regional ecological and environmental conditions. In this study, we expounded the evolution characteristics of the North Branch of Yangtze Estuary in last 30 years, based on the pre-existing results and also the remote sensing image analysis. Together with the recent ecological investigation in the water area, their corresponding effects on species diversity were discussed thoroughly. The results proved that the prominent feature of the evolution was that the middle and upper segments of the North Branch got narrowed significantly, while the lower segment was less narrowed and still had a funnel shape. A large number of reclamations taken place in the middle and upper areas were responsible for this. With the changes of river regime, the water depth, channel volume and the split ratio of water of the North Branch decreased, while the split ratio of sediment went up. These had contributed to the intensive saltwater intrusions into the North Branch, and also the increased risks of the sediment and saltwater spilling into the South Branch. The North Branch evolution altered the salinity conditions of the water, which led to the dominant biomes appeared to be those adapted to the high salinity and brackish water. Furthermore, the variations of the water depth, hydrodynamic and sediment concentration of the water could also have effects on the biomes. However, at present, the North Branch was still an important habitat and nursery area for many biomes, such as the benthic macroinvertebrates, the fishes and so on, and still had higher biodiversity. As a consequence, we need to sustain the ecosystem structure and functions of the area to ensure the sustainable development of the region. We also need a comprehensive analysis on the basis of effective monitoring in the future to reveal the evolution trends of the North Branch and their corresponding effects. |
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| Keywords: | Yangtze Estuary North Branch evolution species diversity |
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