The Impacts Of Oil Pollution On Community Structure Of Plants Rhizosphere Microorganisms In Coastal Wetland

Oil, reputed as "black gold", plays an important role in the global economicdevelopment, and becomes the competing tar get of national resources for many countries.However, it could not be ignored that, the exploration, production, and transportation ofoil and oil products cause a series of environmental problems. Large quantities of oil entersoil, destroying the structure, function and fertility of the soil, and leading to seriouseffects on colonies in the soil and the surrounding ecosystem. Microbial community, theimportant part of the coastal wetland ecosystems, plays an important role to guaranteethe environment functions of wetland be implemented, especially in the purificationfunction. However, microbial community of coastal wetland has a different compositionand community characteristics from Continental and Marine, easily be displaced undernatural disturbances and anthropogenic interference. The result of the displacement isbreak the original balance, destroying the inherent function of the system, reducing theecosystem stability and purification capacity. Therefore, it is extremely necessary toexhibit the impacts of exogenous oil pollution on rhizosphere microbial communitystructure of coastal wetland to the people to arouse the vigilance.The study took Shuangtaizi river reed wetland of Liaodong Bay as the object and oilpollutants as the main exogenous contaminants. A simulation device of reed wetland wasused to carry out the experiment outdoor for six month. Distribution characteristics ofn-alkanes and polycyclic aromatic hydrocarbons（PAHs）in rhizosphere soil of reeds wereanalyzed by GC-MS technology and combined use of PCR-DGGE technology, discussedthe correlations among contents of n-alkanes and polycyclic aromatic hydrocarbons, soilenzyme activities, and the change of microbial community structure, to clarify theinfluence of exogenous oil pollution on community structure of reeds rhizospheremicroorganisms in coastal wetlands. The major findings are summarized as follow：Soil dehydrogenase activities and Catalase activities showed different responses to oilpollution. Soil dehydrogenase activities were positively correlated with the concentrationof oil pollutants, increasing with the increase of the concentration of oil pollutants, while soil catalase activities had no significant correlation with the concentration of oil and wereinhibited by oil contaminants in a certain extent.At the same time, oil contaminants reduced the population of bacteria, fun gi andactinomycetes in the soil of reed root zone, promoted the growth and reproduction of oilde gradation bacteria. The distribution of bacteria, actinomycetes, fun gi population incontrol and experimental group basically in line with-20cm>-10cm>-30cm>-40cm,and petroleum degrading bacteria comply with-10cm>-20cm>-30cm>-40cm. Trends ofthe micro population change have no difference with the time, but the number of threemain soil microbial population in experiment group was lower than that of the controlsignificantly, while the number of oil degradation bacteria was higher than control group.The maximum population of bacteria and actinomycetes both appeared in June, fun gi andpetroleum degrading bacteria both appeared in September in control group. However, inexperimental group, the maximum population bacteria and petroleum degrading bacteriaappeared in June and October respectively, actinomycetes and fun gi both appeared inNovember. PCR-DGGE technology was used to analysis the community structure ofbacterial. Oil pollutants reduced the diversity, and changed the dominant flora of microbialcommunity. An aerobic or facultative anaerobic heterotrophic bacteria was found in theexperiment group. The floras belong to the Proteobacteria phylum, Flavobacteriumclass.