Spatial And Temporal Distribution Of Bacteria In The Seawater And Sediment Of Liao He Estuary And The Community Structure Analysis

The aim of this study was to investigate the abundance of bacteria in seawater and sediment, the distribution and the correlation between them and environmental factors. In 2013, the indicator bacterium(including total coliforms, fecal coliforms, enterococcus, heterotrophic bacteria, petroleum hydrocarbon degrading bacteria, nitrifying bacteria and denitrifying bacteria) and environmental factors were identified both in spring, summer and autumn of Liaohe estuary. Based on this, we want to choose the proper indicator bacteria to present the fecal pollution and environmental factor investigation, sampling and analysis, grasp the abundance of bacteria in water and sediment changes, spacetime distribution characteristics and the correlation among environmental factors, on the basis of the proper instructions estuaries microbes to indicate the change of environmental pollution. At the same time, the use of high-throughput sequencing study of bacterial community structure under different salinity, with 16 S r RNA and r DNA represented the ratio of the bacterial activity(potential growth rate). Analysis the condition of the estuary and changeable environment factors change of bacterial community structure and activity.Bacteria abundance survey results show that the time scale, total coliforms, fecal coliform bacteria in water and sediment, enterococcus, heterotrophic bacteria and petroleum hydrocarbon degradation bacteria abundance: summer > autumn > spring. Nitrifying bacteria and denitrifying bacteria abundance: spring > autumn > summer.In the spatial scales, bacterial abundance is lower than the sediment in the water, Offshore is higher than the sea. Total coliforms and fecal coliforms and enterococcus abundance of change and the environment has a significant correlation between indicators, Fecal coliform, enterococcus and hydrochemical index Si O34 – Si, NH4 +-N, TP and COD, there were significant correlation between the fecal coliforms and Si O34-- Si and correlation coefficient of TP were greater than 0.714, the correlation coefficient of enterococcus and TP and COD were greater than 0.742. Fecal coliform and space-time distribution features of enterococcus and terrigenous pollutants especially closely related to the input of nitrogen and phosphorus. It was significantly positively related to relationship between them, fecal coliforms and enterococcus can reflect the fecal pollution. Salinity is the influence of petroleum hydrocarbon degradation bacterium and one of the major factors of time and space distribution of heterotrophic bacteria, petroleum hydrocarbon content in the water and water temperature also affect the abundance and distribution of reasons, these three constitute the main influence factors of time and space distribution of petroleum hydrocarbon degradation bacteria, And abundance of heterotrophic bacteria has significant positive correlation with phosphate, heterotrophic bacteria in the water to a certain extent, can reflect the phosphate pollution. Nitrifying bacteria, denitrifying bacteria, and the correlation between environmental chemistry index is more complex, temperature, concentration of nutrient substrates, dissolved oxygen content, p H, salinity and sediment of REDOX potential can affect the growth of nitrifying bacteria and denitrifying bacteria breeding metabolic factors, in the spring and autumn, nitrite has significant correlation with nitrifying and denitrifying bacteria.Bacteria community structure analysis results show that the liaohe river m OTUh edge bacteria categories including Proteobacteria, Cyanobacteria, Actinobacteria and Bacteroidetes, door deformation fungi from high to low proportion of phylum of Betaproteobacteria, Alphaproteobacteria, Gammaproteobacteria, in addition to bacillus genus of sheath Sphingobacteriia, Actinobacteria and Flavobacteriia also account for certain proportion. Similarity analysis showed that the whole samples in low salinity(freshwater area) and salinity(brackish water mixed zone) environmental bacteria is relatively close, the similarity and salinity area of bacteria in water and low salt and salinity in the bacterial community diversity differences, There are obvious effect on community structure similarity distance. Estuaries planktonic bacteria in the bacterial community occupies a larger proportion, the free-living bacteria community of planktonic bacteria in the community have important effects on the ecological environment. These Marinobacterium, Paucimonas, Candidatus Planktophila and Candidatus Aquirestis few abundance in seawater salinity areas may not even exist, And some species, such as Bacillus, Planomicrobium, Sphingomonas, Sediminibacterium and Paracoccus are able to adapt to the salinity environment, but it is difficult to survive in low salinity area, and there are some low salinity, bacteria of the genus of bacteria in fresh water salinity areas or the areas with higher salinity can survive and reproduce well, such as Litoricola, Pseudospirillum, Erythrobacter, Candidatus Puniceispirillum and Pseudoalteromonas, etc.Estuarine waters in different salinity gradient of bacterial community diversity index, evenness, community structure and activity were analyzed. Results show that in the whole bacterial community in the 16 S r RNA and abundance of r DNA correlation is low, which suggests that bacteria abundance not well reflect the potential growth rate or the activity of the bacterial community, For some bacteria, such as uncultivate bacteroidetes and addicted to methyl bacteria, etc., the 16 S r RNA and r DNA showed significant positive correlation, In these bacteria bacterial abundance and bacteria growth activities have a very good correlation. The experimental results show that salinity, p H, dissolved oxygen, temperature, nutrient such as physical and chemical environment factors have different degree of impact on the rate of bacterial growth, in the presence of many influence factors, bacteria abundance may not necessarily be the determining factor, estuary has adapted to different salinity and a variety of ecological community of bacteria environmental conditions, salinity is the main factor that affecting the bacterial community structure and activity.