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Material Dispersion Mechanism Maintaining Tropical Mangrove Ecosystems

维持热带红树林生态系统的物质分散机制

基本信息

批准号：
08680559
负责人：
MAZDA Yoshihiro
金额：
$ 1.6万
依托单位：
Tokai University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1996
资助国家：
日本
起止时间：
1996 至 1997
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08680559/
关键词：
mangrove material dispersion coefficient of dispersion drag force numerical experiment particle trajectry coastal environment ecosystem 塩分回復感潮河川

项目摘要

Mangrove ecosystems in tropical/sub-tropical coastal areas play much inportant roles for preservation of natural environment, food resources and coastal protection in grobal scale. However, their quantitative mechanisms are few accumulated, especially from the view of the study of water area. Mangroves colonize in the intertidal area. Their ecosystems are strongly affected by the movement of water due to tide and waves.In this study, we aim mainly to quantify the processes of physical dispersion of water-mass and particles moving with water, and to accumulate the physical information connecting the mangrove ecosystems, according to two methods, the field investigation and the numerical model experiment with computer.The results are as follows ;(1) Field investigation1) For the riverine forest type mangroves (R-type), the flooding over the mangrove swamp from the creek makes the unique material dispersion, ie. "tidal trapping".2) The oxygen budget in the mangrove swamps is strongly controlled by the offshore water flowing into the swamp with tidal motion, the production by photosynthesis and the aeration through the water surface and the consumption at the bottom mud inside the swamps.3) For the fringing type mangroves (F-type), the offshore waves are considerably damped by the drag force of mangrove vegetation. The wave reduction depends on the water depth which varies with tide, because the mangrove trees have manny drag bodies (prop roots and pneumatophore) near the bottom. Accordingly, the magnitude of the material dispersion depends on the conditions of not only waves in offshore but also tide, the density of vegetation and its vertical distribution.(2) Numerical experiment1) For the R-type, the process of particle dispersion is very different from the usual river which has not mangrove swamp (ie.flooding area).2) The magnitude of the dispersion coefficient in the R-type varies depending on the density of mangrove vegetation.

热带/亚热带沿海地区红树林生态系统在全球范围内对自然环境、粮食资源和海岸保护具有重要作用。然而，对其定量机制的研究却很少，特别是从水域研究的角度来看。红树林生长在潮间带。它们的生态系统受到潮汐和波浪引起的水运动的强烈影响。本研究主要通过野外调查和计算机数值模式试验两种方法，对红树林生态系统的水质量和水粒子的物理扩散过程进行量化，积累红树林生态系统之间的物理信息。研究结果如下：(1)对于河流林型红树林（r型），来自小溪的洪水淹没了红树林沼泽，造成了独特的物质弥散。“潮汐陷阱”。2)红树林沼泽的氧收支受潮汐运动流入沼泽的近海水、光合作用的产生和水面的通气性以及沼泽内部底部泥浆的消耗等因素的强烈控制。3)对于边缘型红树林（f型），近海波浪受到红树林植被拖曳力的显著抑制。波浪的减少取决于随潮汐变化的水深，因为红树林在底部附近有许多拖体（支柱根和气团）。因此，物质扩散的大小不仅与近海波浪条件有关，还与潮汐条件、植被密度及其垂直分布有关。(2)数值实验1)对于r型河流，颗粒弥散过程与通常没有红树林沼泽（即红树林沼泽）的河流有很大不同。洪水区域)。(2) r型的分散系数大小随红树林植被密度的变化而变化。