Studies on the Function of Wetland and Shallow Aquatic Ecosystems for Environmental Conservation

通过对湿地和浅水生态系统环境保护功能的研究，得出以下结论：(1)为评价降雨对城市浅水生态系统的影响，在名古屋大学收集了1995年的降雨样本并进行了分析，并与名古屋市近10年的降水数据进行了比较。结果表明，降雨组分中硫化物含量呈减少趋势，氮化物含量呈增加趋势，表明降雨可能是低营养生态系统的富营养剂。(2)为了阐明浅水生态系统在硫氮循环中的特点，在名古屋市郊的一个小池塘及其周边湿地进行了硫氮平衡、微生物对有机物降解的影响以及反硝化菌群的研究。结果表明，湿地对高浓度硫酸盐入流和降水供氮具有较大的缓冲作用。(3)为了评估降水养分供给对低营养湿地的影响，在对钏路湿地进行氮循环微生物区系野外研究的同时，进行了甲烷、氧化亚氮和氢气通量测量。结果表明，降水对营养型沼泽的硫供应至关重要，其中硫酸盐在夏季完全耗尽。在氮组分方面，沼泽（高沼地）中有大量的自由生活固氮细菌，而沼泽（低沼地）中没有发现固氮细菌，这说明了环境中氮的营养水平。(4)浅层水生生态系统对下游流域的养分负荷具有重要的缓解作用，可以抑制养分的最终流入或降水负荷。为全面保护环境，应妥善管理湿地或浅水系统。少

From 2 years' study to estimate the function of wetland and shallow water ecosystem for environmental conservation, the following results were obtained.(1) In order to estimate the effect of rainfall on a shallow aquatic ecosystem in the urban area, rain samples were collected and analyzed at Nagoya University during 1995, and the data were compared with those of Nagoya city during recent 10 years. The result showed recent trend in decreasing sulfur and increasing nitrogen compound in the rain component, which indicated that rain might be eutrophication agent on the oligotrophic ecosystem.(2) In order to elucidate the characteristics of shallow aquatic ecosystem in the sulfur and nitrogen cycling, filed studies concerning on the sulfur and nitrogen budget, microbial activities on the degradation of organic matter, and the denitrifying bacterial flora were carried out at a small pond and its surrounding wetland area in Nagoya city suburb. The result showed that wetland had large bufferi … More ng function against higher concentration of sulfate inflow and nitrogen supply through precipitation.(3) In order to estimate the effect of nutrient supply through precipitation on oligotrophic wetland, field studies on the nitrogen cycling microbial flora were carried out in parallel with flux measurement of methane, nitrous oxide and hydrogen at Kushiro wetland. The result showed that sulfur supply through precipitation was crucial for ombrotrophic bog, where sulfate was completely depleted in summer. As for the nitrogen component, the fact that free-living nitrogen fixing bacteria appeared abundant in bog (high moor) but not detected in fen (low moor) indicated the nutrient level of nitrogen in the environment.(4) The shallow aquatic ecosystem plays an important mitigating role for nutrient loading on the lower watershed agaist eventual inflow or loading of nutrients by precipitation. Wetland or shallow aquatic system should be managed properly for the total environmental conservation. Less