| Wetlands as transitional zone between land and water, not only have the characteristics of the terrestrial ecosystem, but also have the characteristics of aquatic ecosystems, they have many unique characteristics and function, they also can create a good living environment for many different kinds of plants, animals, and a variety of microorganisms ,meanwhile, the biodiversity of this ecosystem is very large and complicated. Wetlands ecosystem play an important role in the ecological environment, in addition to compensate for the local water, also showed a greater ecological function,such as flood control and water storage, regulating regional climate, protecting biodiversity, maintain the balance of ecological system, fixed carbon dioxide,et al, at the same time, they also have the obvious degradation of pollutants, the ability of purifying water quality. Wetlands not only reflects the good economic benefit, but also has certain social benefit and landscape value and the value of education. Wetlands in the finished water quality purification function mainly through the soil, plants, microorganisms in the process of the compound ecosystem, to the physical, chemical, and biological triple coordinating role to realize the high efficiency of sewage purification purposes. The microorganism in wetlands occupied an extremely important role in this process, they not only assume the role of maintaining the ecosystem balance, but also play a very important role in pollutant removal. When wetlands ecosystem play role in the process of water purification, the various microbial activity is the main channel to realize organic matter degradation and transformation, abundant quantity and variety of microorganism take enough disintegrator for the natural,complex and highly efficient sewage purification system. Through the review found that microbes in wetland research widely at home and abroad, but there is significant research shortage phenomenon lies in the western region.Ningxia plain due to its special natural geographical conditions, has created plenty of wetlands resources, and the wetlands have various types and widely distributed. Yinchuan Yellow River wetland in Ningxia was relatively rare with less affection by human activities in all of wetland resources, It plays an important ecological service function in climate, water, biodiversity, natural landscape, and many other aspects of Yinchuan plain, it also plays an important role in the ecological security of Yellow River and ecological construction of Yinchuan plain. This study used the method of the water quality detection and evaluation method to field survey,sampled and analysised the water quality situation and the bacteria number of 7 different areas in the Yinchuan Yellow River wetland, experiment on the preliminary understanding of the bacterial colonies and space-time distribution of all kinds of pollutants in Yinchuan Yellow River wetland section A zone, found that there exists a significant correlation between the bacteria and the organic pollutants removal rate, then used the current relatively mature molecular biology method determines the formation of the bacteria in Yinchuan Yellow River wetland, further simulated artificial wetland for A 60h sewage simulation experiment to determine the ability of six strains of bacteria were determined, ultimately selected two strains of bacteria with a good degradation efficiency on CODcr, NH3-N, and TP in water, used traditional identification method research the physiological and biochemical identification of two strains, constructed the bacteria phylogenetic tree of one strains of bacteria to determine its biological status. The experimental study not only can improve the depth of the wetland function bacteria research in Ningxia Yinchuan plain, improve the wetland water environment capacity, give full play to the ecological service function of wetland resources, provide technical support in the protection of the wetland resources and effective use, lay a theoretical basis for the water resources highly effective circulation use in the Yinchuan plain.The conclusion is as follows:(1)The water pollutants concentration distribution of the Yinchuan Yellow River wetland has certain change in different periods, and the difference is bigger. Spring comprehensive pollution index is relatively high, beyond the average annual comprehensive pollution index; Comprehensive pollution index is lower than the spring and summer, but also exceed average annual comprehensive pollution index, change is obvious;comprehensive pollution index is relatively low in Autumn, and the fluctuations exist between the various points; the wetland freezes phenomenon in Winter, so the change of the pollutants is not very significant, and the comprehensive pollution index is not very significant. Overall, the spring water quality is relatively poor, followed by summer. In addition, the sample point average total number of bacterial colonies in the presence of dynamic change of the four seasons, show a overall trends that summer> autumn>spring>winter.(2)There is no correlation between the bacteria and the removal rate of pollutants or pollutant concentration in spring and autumn;the concentration of the BOD5 and bacteria number has a negative correlation(P<0.05, r=0.844)in Summer;while in winter, the removal rate of organic matter and bacteria number appears a positive correlation (P<0.05, r=0.863).(3) After bacterial culture and purification,73 purified cultures of Yinchuan Yellow River wetland water were obtained,by 16 s rDNA sequencing and NCBI database, obtained 7 genera and 23 kinds of bacteria, including 9 strains of Bacillus,5 strains of Pseudomonas,3 strains of Acinetobacter,3 strains of Aeromonas,1 strain of Planomicrobium,1 strain of Shewanella, and 1 strain of Bacterium.(4) Through carries on the domesticated raise to 23 bacteria after bacterial culture, there are 6 strains of bacteria growth conditions are relatively good, pollutants degradation ability of 6 strains of bacteria to further research. Strains in the sewage for 60h, the pollutant concentration change basic different strains of pollutant degradation ability in different trends,and each are not identical, also the same strain on the ability of different pollutants is difference. Strain HG1, HG5, HG4 and HG2 have a best CODcr degradation effect, the removal rate were 49.06%,35.45%, 31.34% and 49.06% in sewage; Strain HG4, HG1, HG6 and HG3 have best degradation effect for NH3-N, removal rate were 49.53%, 47.1% ,33.64% and 49.53%; Strain HG1, HG4, HG2 and HG3 have best degradation effect for TP,removal rate of 35.82%,25.3%,22.23% and 25.3%.To sum up, there are 23 strains were isolated by purified bacteria strains from Yinchuan Yellow River water, through pollutants degradation ability research, strain HG1 has a degradation ability of CODcr, NH3-N and TP, so build phylogenetic tree for HG1 construct, the final judgment it belongs to the classification status of fluorescent pseudomonad. |
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