Effects of Human Activity on Water Enviroument of Mire

在北海道，我们仍然有许多沼泽地，那里生长着特定的植物。由于人类的活动，它们正在逐渐消失。在自然条件下，对Sarobetsu沼泽和Tsukiga-Umi沼泽的地下水水质进行了调查，并对维持沼泽的水耕系统进行了研究。结果表明：（1）上升沼泽地下水水质环境独特，以腐殖酸为主的有机质含量高，pH值低，平均为4.8。(2)隆起沼泽上层地下水中常见无机组分浓度较低，成分与雨水相似。利用雨水培植地下水以维持天然沼泽是完全必要的。(3)在隆起沼泽区（泥炭藓区），由于营养盐浓度低，有机营养盐占优势，分解活性极低。(4)而高水位区的Sarobetsu沼泽的营养状态是贫营养的，低地下水位区的富营养化，其中无机形式的氮占主导地位。(5)在竹草入侵区，有机质浓度与溶解态氮（尤其是无机氮）浓度呈正相关。在地下水位较低的情况下，营养物质处于易被细菌分解而溶解的状态。(6)在竹草侵入的地方，铁和硅酸盐的浓度增加。不应忽视地质特征的影响。

In Hokkaido, we still have many mire fields where specific plants grow. They aregradually disappearing by human activities. We resarched the quality of ground water in the mire and studied the water cultivation system that maintains the mire under the natural condition at Sarobetsu mire and Tsukiga-Umi Mire. The results are summerized as follows ;(1) The ground water quality of rised bog is in a unique circumstance, with high concentration of organic matters composed of humic-acid and with low pH,4.8 on the average.(2) In tne ground water of the upper layr of the raised bog, the concentration of the common inorganic components is low and the composition is similar to rain water. It is absolutely necessary to cultivate the ground water by rain water to maintein the natural mire.(3) In the region of raised bog (Sphgnum moss area), the decompositon activity is extremely low as the concentration of nutrients is low and the organic nutrients are dominant.(4) While nutrient state of the high water level region of the Sarobetsu Mire is oligotrophic, that of the low ground water level region is eutrophic where inorganic form of nitrogen is dominant.(5) In the region where bamboo grass invades, the concentration of organic matters and that of dissolved nitrogen (especially inorganic nitrogen) have a positive relationship. Nutrients are in a state liable to dissolve by the bacterial decopositon under the low level of ground water.(6) Where bamboo grass invades, the concentration of Iron and Silicate increases. Influences of geological features should not be disregarded.