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CONSERVATION OF TROPICAL SEAGRASS BEDS WITH SPECIAL REFERENCE TO THEIR ROLE ON FUNCTION OF COASTAL ECOSYSTEM

热带海草床的保护，特别是其对沿海生态系统功能的作用

基本信息

批准号：
12575032
负责人：
KOIKE Isao
金额：
$ 9.34万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2002
项目状态：
已结题

项目摘要

Field studies were conducted under the title "Conservation of tropical seagrass beds with special reference to their role on function of coastal ecosystem" to quantify the stress of terrestrial nutrients, sediment materials and human changes of coastal line on seagrass ecosystem including benthic populations facing to the Andaman Sea side of Thailand. Followings are major research outcomes of this project.1) We analyzed how the dominated species of seagrass adapts to external environmental change such as sediment supply and decrease of light intensity. And we indicated the importance of morphological adaptation of seagrasses including the fine roots of vertical rhizomes, as well as adjustment of photosynthetic products distribution among upper and below bottom.2) Stable isotope ratios of nitrogen, carbon and sulfur within the various parts of seagrasses could be used as a good indicator of small scale environmental stress. on seagrass metabolisms3) Comparison of species diversity and biomass distributing different environmental setting, from the location of big river mouth to that of no river inflow influence, indicated that both biomass and species diversity of seagrass decreased with the increase of river influences at least in this study area.4) Based on the field observations of physical forcing causing re-suspension of seagrass sediments, we identified three factors, i.e., tidal current, wind induced re-suspension and inflow or terrestrial solids. Even within the rather narrow area of seagrass beds, spatial and temporal variation of these three factors were observed, also effecting on metabolisms of benthic organisms associated with seagrass beds,5) Food preference of dugong for different types of seagrass species was examined and importance of Halophila beds for the diet of dugong of this area.

进行了题为“热带海草床的养护，特别是关于其对沿海生态系统功能的作用”的实地研究，以量化陆地营养物、沉积物和沿海线的人类变化对海草生态系统的压力，包括泰国安达曼海一侧的底栖生物种群。主要研究成果如下：1）分析了海草优势种对沉积物供给和光照强度降低等外部环境变化的适应性。海草的垂直根茎的细根以及光合产物在底层和上层之间分配的调节等形态适应的重要性。2）海草不同部位的氮、碳、硫稳定同位素比值可以作为小尺度环境胁迫的一个很好的指示因子。3）通过比较不同环境条件下（从大河口位置到无河流入流影响的位置）海草的物种多样性和生物量分布，表明至少在本研究区，海草的生物量和物种多样性都随着河流影响的增加而减少。4）根据引起海草沉积物再悬浮的物理强迫的现场观测，我们确定了三个因素，即，潮汐流、风引起的再悬浮和流入或陆地固体。即使在相当狭窄的海草床区域内，这三个因子的时空变化也被观察到，并影响着与海草床相关的底栖生物的代谢。5）研究了儒艮对不同类型海草的食物偏好，以及盐生菌床对该区域儒艮食物的重要性。