Development of aquatic plant model and analyses of carbon & nutrition dynamics in lake/river environment

水生植物在湖泊和河流水质中起着重要的作用。但是，由于评价效率的困难，很难将工厂制度引入到实际经营中。在这种情况下，从野外观测中获得必要的数据集，然后进行子模块的设计，最终开发出管理中可用的数学工具。在野外观测中，对芦苇（Phragmites australis）、柞树（Typha augustifolia）和紫荆（Zizania latifolia）等重要的应急树种进行了物质转运系统的测定。它也适用于夏季切割的种群，通常用于从水中获取营养。在此基础上，建立了这些物种的生长模型。然后应用该模型获得了不同条件下的生长特性、养分收获效率、植物体养分循环等重要特征。结果表明：1)奥地利Nieseidlarsee芦苇林分的碳、氮、磷循环。2)在一定的季节气象模式下，Typha属植物的地上、地下生物量处于纬度平衡阶段。具体地说，次枝形成的作用是纬度。3)利用该模型对两个新兴物种的竞争进行了评价。4)利用该模型对刈割收获养分量进行评价，得出刈割去除养分的最佳时间。除上述结果外，还得到了潜生物种、潜生植物和附生植物之间的竞争关系，以及潜生植物对流动水体中有机物的积累速率。

Aquatic plants have an important role in water quality in lakes and rivers. Difficulties to evaluate efficiency, however, have made it hard to introduce the plants system into practical managements. Under such circumstances, necessary datasets were obtained from the field observation and then sub-modules were made, aiming to finally develop the mathematical tool available in management. In the field observation, material translocation system was measured for some of important emergent species such as Phragmites australis, Typha augustifolia and Zizania latifolia, by sampling shoots and rhizomes monthly. It was also obtained for the population cut in summer time, often conducted to harvest nutrient from water. Based on these results, the growth model was developed for these species. Then the model was applied to obtain important characteristics regarding the growth characteristics under various conditions, efficiency in nutrient harvesting, nutrient cycle through the plant body, etc. The following results were obtained : 1)Carbon, nitrogen and phosphorus cycles was obtained in the Phragmites australis stand in Nieseidlarsee in Austria. 2)Latitudinal effects were obtained for above and belowground biomass of Typha spp. in the equilibrium, stage under a fixed seasonal meteorological patterns with respect to latitude. The function of secondary shoot formation was elucidated as latitude specifically. 3)The competition of two emergent species was evaluated by the model. 4)The amount of harvested nutrients by cutting was evaluated by the model and the best cutting time to remove nutrients was obtained. Other than these results regarding emergent species, the competition between the submerges species, Potamogeton perfoliatus and epiphyton, and the accumulation rate of organic materials in the flowing water by Potamogeton spp. were obtained.