Study On The Spatial And Temporal Distribution And Community Structure Of Microorganism In The Sediment Of Hun River And Correlation With Its Environmental Factors

With the acceleration of industrialization and urbanization, rivers and other natural water environment in China are being seriously polluted. Large amounts of pollutants have deposited into the sediment, thus sediment are one of the most abundant holders of microbes. On one hand, microorganism can affect the distribution and transformation of pollutants in the sediment of river through its biochemical activities.Therefore, it has an important significance on maintaining the stability of the water ecological system; On the other hand, the changes of the environmental conditions also can affect the microbial community structure in the sediments directly or indirectly.Therefore, it is of great significance to know the microbial community distribution in sediments for understanding the history of pollution, revealing the migration and transformation of pollutants, and carrying out bioremediation of the pollution system.However, the current researches on the microorganisms in river sediment were just one time study, meanwhile river is greatly influenced by the seasonal changes, such as temperature, runoff, rainfall so on, so that the microbial community structure of the sediment in the river will also have seasonal differences.Therefore, Hun River, which is a typical river in the northeast of China, was detected as the research object in this study. The experiment analyzed the differences of overlying water quality, pore water quality and microbial community structure in the sediments between normal season, dry season and wet season. Correlation analysis was carried out to study the relationship between water quality and microbial diversity. Thus,we can have a deep understanding of the diversity and distribution of microorganisms inthe river sediment of different seasons, can explore the potential impact of water quality pollution on its sediment and provide a scientific basis for the protection and management of river ecological system. The main conclusions are as follows.(1) Cluster analysis results showed that all the samples were classified into two main groups according to the pollution degrees of overlying water and pore water. One was the regions in the upstream of Shenyang city, the other was the regions in the downstream.(2) DGGE results showed that both the Shannon-Wiener Index and the abundance of bacteria and archaea increased at the upstream and then decreased gradually at the downstream. Additionally, the Shannon-Wiener Index and abundance of bacteria were greater than those of archaea along the whole river. Compared with the archaea in the sediments, the bacterial community displayed significant regional differences.(3)The diversity of N-DAMO’s 16 S rRNA genes and its pmo A genes changed with different seasons samely, the amount of diversity was in the order: normal season>wet season>dry season; The abundance of its 16 S rRNA genes also had obvious seasonal differences, the amount of abundance was in the order: normal season> dry season> wet season; Correlation analysis of diversity of N-DAMO and water index indicated that the Shannon index of N-DAMO’s 16 S rRNA genes was only related to the concentration of total phosphorus in pore water.