SUTDIESON THE METHANEFLUX ANDITS CONTROLLING IN NATURAL WETLANDS

对甲烷通量及其控制因素的研究是在长冈河的两个自然湿地、库希罗·梅尔和河的嘴巴区域进行的。“原始人被选择为最大、最自然的湿地，而较深的湿地则是代表性的湿地，受到了人类的巨大影响。”在1998年7月和8月期间的实地研究中，在低密度下的甲烷通量（14 - 17毫克/米D12-D1/小时）清除了低密度下的那些（9 - 10毫克/米D12-D1/小时），在以前的研究中通常发现的最高通量。1999年8月，甲基通量在5个不同的土壤部位进行了测量，通量范围为2.4 - 15毫克/米，D12-D1/小时，最高通量在一个Equisetum流体部位发现，有相同的空心支架作为芦苇茎。稳定的碳比率（δ D113 D1C）中收集的甲烷从两个芦苇茎和泡沫在低moor没有孵化的情况下进行了分析，每mil为-55.1±0.2，每mil为-59.8±0.8。这一结果表明，乙酸降解过程对芦苇干甲烷有更多的贡献，而H-D22-D2/CO-D22-D2过程对泡沫甲烷有更多的贡献。在另一方的手中，在Nagara河的下游延伸，甲烷通量在3公里，6公里的站测量了3公里（仅上游至河嘴宽度），1999年7月距河嘴23公里，在23公里和6公里站分别为0.6微克/米D12-D1/小时和1.7毫克/米D12-D1/小时和23公里和6公里站的流量，相应地。在3公里的火车站上发现了一个甲烷流体。这些结果表明，从裂缝到淡水生态系统的构造的河口屏障证实了从下游到达的河口屏障的增强的甲烷通量。

Studies on the methane flux and its controlling factor was conducted in two natural wetlands, Kushiro mire and river mouth area of the River Nagara. The former was chosen as the largest and highly natural wetland and the latter was a representative wetland received heavy human impact. In Kushiro mire during field studies in July and August, 1998, methane fluxes in alder moor (14〜17mg/mィイD12ィエD1/h) exceeded those in low moor (9〜10 mg/mィイD12ィエD1/h), where the highest fluxes were usually obtained in the former studies. In August 1999, methane flux were measured in 5 sites with different vegetation in alder moor, and flux range of 2.4 〜15 mg/mィイD12ィエD1/hr and the highest flux was obtained at a site of Equisetum fluviatile, which has the same hollow stalk as reed stem. Stable isotope ratio of carbon (δィイD113ィエD1C) in methane collected from both reed stem and bubble at low moor without vegetation were analyzed and -55.1±0.2 per mil for the former and -59.8±0.8 per mil for the latter were obtained. This result indicates that acetate degradation process was more contributed for reed stem methane, and that HィイD22ィエD2/COィイD22ィエD2 process was more responsible for bubble methane.On the other hand, in the lower reach of the River Nagara, methane fluxes were measured at stations of 3km, 6km (just upper reach of river mouth barrage) and 23km from the river mouth in July 1999, and fluxes of 0.6μg/mィイD12ィエD1/h and 1.7mg/mィイD12ィエD1/h were obtained at 23km and 6km station, respectively. No methane flux was obtained at 3km station. These results indicate that river flow stopping and environment change from brackish to freshwater ecosystem by the construction of river mouth barrage evidently enhanced methane fluxes from lower reach of the river.