Studies on methods for management of tropical lake ecosystems under human impact

人类影响下热带湖泊生态系统管理方法研究

• 批准号: 03041109
• 负责人: ARUGA Yusho
• 金额: --
• 依托单位: Tokyo University of Fisheries, Faculty of Fisheries
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Overseas Scientific Survey.
• 财政年份: 1991
• 资助国家: 日本
• 起止时间: 1991 至 无数据
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-03041109/
• 关键词: wetland ecosystem; lakes; human activity; soil; tropical; water quality; benthos; plankton; productivity

In Songkhla Lake (Thale Sap Songkhla), Secchi disc depth, water temperature, salinity, pH, nutrients, organic matter, heavy metals, DO, SS, chlorophylls, plankton, benthos and photosynthesis of phytoplankton were investigated at 7 stations.Turbidity of lake water was very high, which resulted from very high concentration of suspended solid and disturbed accurate analyses of water quality. Water temperature was 28-31ﾟC, DO 6-8 ppm, pH 7-9, salinity 0-33 % C, and phytoplankton chlorophyll a mostly 2-18 mg/m^3 (18-45 mg/m^3 in December). Photosynthetic capacity of phytoplankton was comparatively high, 25-30 mgO_2/chl. a mg/hr with photo-inhibition in some cases.As for benthic animals, 31 species were found all through the stations, 5-15 species at a station. Indivisual density was 120-1170/m^2. The number of species and individual density were low as compared with the normal levels found in inland seas and coastal areas, especially the density being 1/10 to 1/100 of the level in those areas. Polychastes, molluscs and crustaceans were found almost in the same number of species, and from biogeographical viewpoint most of them are tropical and subtripical species found in the Indo-Pacific areas. They are mostly filter-feeders, and only a few species are oninivorous and carnivorous. Benthos biomass was high in the central and western part of the lake and low in the eastern part and the channel connecting the lake with open ocean, suggesting the environmental stress due to salinity changes and water flow in the latter areas.Suspended solid was 44-127 mg/l and the ignition loss was 12-19%, suggesting prominent resuspension of bottom sediment in lake water. Among heavy metals Mg (49.6 ppm), Ca (19.8 ppm), Si (5.10 ppm)and AI (1.30 ppm)were abundant in lake water.

在宋卡湖（Thale Sap Songkhla），7个站对塞奇盘深度、水温、盐度、pH、养分、有机物、重金属、DO、SS、叶绿素、浮游生物、底栖生物和浮游植物的光合作用进行了调查。湖水的浊度非常高，这是由于悬浮固体浓度非常高，干扰了水的准确分析 质量。水温28-31°C，DO 6-8 ppm，pH 7-9，盐度0-33 % C，浮游植物叶绿素a大部分为2-18 mg/m^3（12月为18-45 mg/m^3）。浮游植物光合能力较高，为25～30mgO_2/chl。毫克/小时，在某些情况下具有光抑制作用。至于底栖动物，整个站发现了31种，一个站发现了5-15种。个体密度为120-1170个/m^2。与内海和沿海地区的正常水平相比，物种数量和个体密度较低，尤其是密度为该地区水平的1/10至1/100。多贞节类、软体动物和甲壳类动物的种类数量几乎相同，从生物地理学的角度来看，它们大多数是在印度洋-太平洋地区发现的热带和亚热带物种。它们大多是滤食性动物，只有少数种类是肉食性和肉食性的。湖泊中部和西部底栖生物生物量较高，东部及连接湖泊与公海的水道较低，表明后者受到盐度变化和水流的环境胁迫。悬浮固体为44-127 mg/l，灼烧损失为12-19%，表明湖水中底部沉积物的再悬浮现象突出。湖水中重金属含量丰富，其中镁（49.6 ppm）、钙（19.8 ppm）、硅（5.10 ppm）和铝（1.30 ppm）。