| 摘要: |
| 根据1985 - 1991年对长江三角洲和苏北潮滩-潮沼系统中潮流和波浪观察、滩面高程量算、沉积物分析和人工海草试验，研究植物对潮滩动力和沉积的影响。结果表明，（1）植物可使底层流速降低20％ - 60％，使波浪能量大部分被吸收。（2）沼泽前缘存在侵蚀机制，而沼泽的主体则有明显的促淤现象；沼泽中的沉积速率可达光滩的9倍以上。（3）沼泽前缘沉积物有粗化现象，沼泽主体则是细化环境；沼泽是孢粉相对富集的场所；沼泽中各种物理沉积构造不易形成和保存。 |
| 关键词: 潮沼植物 动力 沉积 潮滩演变 |
| DOI： |
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| THE ROLE OF VEGETATION IN MUD COAST PROCESSES |
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Yang Shilun, Chen Jiyu
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Institute of Estuarine and Coastal Research, East China Normal Univercity, Shanghai 200062
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| Abstract: |
| The role of vegetation in dynamic and sedimentary processes was revealed in 1985 - 1991 based on current, wave, and flat height surveys and analyses of sediments and seaweed culture area in the tidal flat and salt marsh system of the Changjiang Delta and North Jiangsu coasts. The study showed: (l) The current velocity in the vegetative area was always smaller than (average and maximum velocity coefficients were respectively 0.71 and 0.73) that of the bare flat area having the same altitude. In the seaweed culture region near the middle tidal line, the average and maximum velocity coefficients were respectively 0.39 and 0.61 (for neap tide) and 0.78 and 0.81 (for spring tide) of that outside the region. (2) Before (after) total submersion of the vegetation, most (little) of the wave energy could be absorbed by the marsh. (3) Erosion occurred at the marsh lowest vegetative boundary, while accumulation was enhanced and could be 9 times that in the bare flat. (4) The marsh boundary sediments were usually coarser than those in the bare flat or in the main marsh area, where sediments were much finer and had high content of filmy minerals, and spores and pollens. (5) Sixty sedimentary box samples were obtained from the Changjiang Delta tidal flat and salt marsh system. Sedimentary stratification was obvious in 90% of the bare flat samples, but was obscure, and observed in only 15% of the marsh samples.
This study suggests that vegetation changes the water energy, the erosion-accumulation process, and distribution of sediments, and that the seasonal variation of vegetation controls the annual evolution of the marsh bottom surface. |
| Key words: Tidal marsh vegetation, Dynamics, Sedimentation, Tidal flat evolution |
