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Littoral ecosystems of tropical lowland lakes : their structure and response to water level change

热带低地湖泊沿岸生态系统：其结构和对水位变化的响应

基本信息

批准号：
15405001
负责人：
IWAKUMA Toshio
金额：
$ 3.78万
依托单位：
HOKKAIDO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2004
项目状态：
已结题

项目摘要

We studied the mechanisms of maintaining biodiversity and material cycling in response to water level change in lowland oxbow and floodplain lakes of Borneo (Kalimantan).1.Bathymetrical maps were drawn for eight lakes along the Kahayan River. These lakes were categorized according to their hydrological connectivity with the main river at high and low water levels.2.Water quality changes were monitored in interconnected lakes during a period from dry season to wet season and confirmed the occurrence of vertical mixing of lake water during the high water level. Lake water quality changed greatly affected by the surface and ground waters from the surrounding peatlands and by the water from the main river. Measurement of phytoplankton primary production and litter flux indicated the dependence of lake ecosystem on the allochthonous organic matter.3.Diversity and biomass of organisms in oxbow and floodplain lakes were controlled by the lake's hydrological connectivity to the main river. Flo … More ating macrophyte such as water hyacinth harbored many invertebrates at its root system and playd an important role in maintaining zooplankton biomass.4.Forest clearing in the watershed basin deteriorated pond water quality in lowering water level and pH and increasing SO_4 concentration, which in turn, decreased zooplankton density. Both photosynthetically active radiation and UV light reaching lake surface are expected to increase after forest clearing. UV radiation enhanced DOC decomposition and community respiration during the incubation experiment of lake water. Possibility of increase in rotiferan biomass under enhanced bacterial loop should be examined in the future.5.Land development and the subsequent decrease in water level may finally reduce fish production, the mechanism of which should be studied further. Feasibility studies are needed to test the applicability of traditional farming and fishing methods using aquatic macrophytes such as water hyacinth for improving water quality. Less

本文研究了婆罗洲（加里曼丹）低地牛轭湖和洪泛平原湖的生物多样性和物质循环对水位变化的响应机制。根据高、低水位时湖泊与主要河流的水文连通性，对这些湖泊进行了分类。2.通过对枯水期到丰水期的水质变化监测，证实了高水位时湖水垂直混合的发生。湖泊水质受周围泥炭地的地表水和地下沃茨以及主要河流来水的影响变化很大。浮游植物初级生产力和凋落物通量的测定表明湖泊生态系统对外来有机质的依赖性。3.牛轭湖和洪泛区湖泊生物多样性和生物量受湖泊与主河流的水文连通性控制。Flo ...更多信息水生植物如水葫芦的根系是无脊椎动物的栖息地，对维持浮游动物的生物量起着重要作用。4.流域内的森林砍伐使池塘水质恶化，水位下降，pH值降低，SO_4浓度升高，浮游动物密度降低。森林砍伐后，到达湖面的光合有效辐射和紫外线都将增加。在湖水培养实验中，紫外辐射促进了DOC分解和群落呼吸。加强细菌环对轮虫生物量增加的可能性有待进一步研究。5.土地开发和随之而来的水位下降最终可能会减少鱼类产量，其机制有待进一步研究。需要进行可行性研究，以测试利用水葫芦等水生大型植物的传统耕作和捕鱼方法是否适用于改善水质。少