Ecological function and functional diversity of aquatic plant vegetation

为了评价水生植物群落对沿岸的带反硝化作用的影响，在自制的1180 mm，φ 320 mm的丙烯酸盐箱中建立了现场实验系统，探讨了霞浦湖反硝化作用的季节变化。该室具有pH、氧化还原电位（ORP）、溶解氧（DO）和空气温度的测量传感器。一个空气乐趣和泵也解决了。在实验地点的700 mm深度处设置室。反硝化评估方法采用乙炔抑制技术（Yoshinari et al.，1977年）。建立了两个实验地点：有和没有植被（芦苇maces，香蒲），以及有和没有添加乙炔气体的腔室。添加的乙炔气体为10%v的空气+腔室的液相。以NaNO_3溶液作为反硝化菌的基质，使其浓度达到1 mg/L（<-1>以NO_3 ~- - N计） ...更多信息 在每个室的液相中。实验结果表明，乙炔抑制法适用于本实验系统，因为加入乙炔气体后，反应室中N_2O浓度明显高于不加入乙炔气体的反应室。与裸地相比，植被地的N_2O浓度较高（5月份，植被地为6.0mgN m·<-2>d ~（-1<-1>），裸地为1.8mgN m·<-2>d ~（-1）<-1>）。因此，可以确定植被样地的反硝化活性高于裸地。反硝化活性随季节的变化规律为：11月&gt; 7月&gt; 5月。反硝化作用对NO_3 ~-的去除率与反硝化活性的变化趋势一致。反硝化活性与液相氧化还原条件有很高的相关性，说明枯落物对反硝化活性起着重要作用，秋冬季节枯落物的增加为细菌提供了可利用的有机质和栖息地。因此，沿岸的水生植物群落对湖泊和沼泽的氮去除具有重要作用。少

In order to evaluate an influence that aquatic plant communities contribute to denitrification activities in littoral zone, in-situ experiment system was developed and seasonal changes of denitrification activities were discussed in Lake Kasumigaura.An acrylic chamber (1180 mm, 320 mm φ) for the experiment was manufactured. This chamber has measuring sensors for pH, oxidation-reduction potential (ORP), dissolved oxygen (DO) and air temperature. An air fun and a pump were also settled. The chambers were set at the depth of 700mm of the experiment site.A denitrification estimating method adopted acetylene inhibition technique (Yoshinari et al., 1977). Two experiment sites were established : the chambers with and without vegetation (reed maces, Typha latifolia), and the chamber with and without addition of acetylene gas. Added acetylene gas was 10%v of air + liquid phase of the chamber. As a matrix for denitrification bacteria, NaNO_3 solution was added to become 1 mg L^<-1> as NO_3^- - N … More in the liquid phase of each chamber. The denitrification activities were measured for 24 or 48 hours.The use of acetylene inhibition technique was applicable to this experiment system, since higher N_2O concentration was found in the chamber with acetylene gas addition than without. Compared with bare site, high N_2O concentration was detected in vegetation site (In May ; vegetation site : 6.0 mg N m^<-2> day^<-1>, bare site : 1.8 mg N m^<-2> day^<-1>). Therefore, it was confirmed that the denitrification activities in vegetation site was higher than in bare site. The denitrification activities varied with season, with the order : Nov. > Jul. > May. >Apr. Furthermore, NO_3^- removal ratio caused by the denitrification showed in the same change with the denitrification activities. There was high correlation between the denitrification activities and oxidative-reduced conditions in liquid phase.These results suggested that withered plants played an important role for the denitrification activity : withered plants increased in autumn and winter provided available organic matter and habitats for the bacteria. It was concluded that aquatic plant communities in littoral zone were very important for nitrogen elimination in lakes and marshes. Less