Effects Of The Dalian Oil Spill On Bacterial Community In Coastal Sediments

In July2010, an oil pipeline explosion occurred in Dalian. The spilled crude oil is very difficult to degrade in the environment, due to its poor volatile. Therefore, it is necessary to make a continuous evaluation on local biological damage and restoration.In this study, bacterial diversity and community structure in eight sediment samples collected from Dalian Bay and Inscriptions Beach before and after the oil spill (covered2years) were analyzed, using an improved double fluorescence labeling terminal fragment length polymorphism (T-RFLP) technique, for a preliminary evaluation on biological damage and restoration in this area.Results obtained in this thesis included:1. Jaccard’s index analysis of the two plots revealed that the similarities of community structure before and after the oil spill were quite low. But as time went on, relatively higher similarities were obtained.2. Comprehensive analysis on Shannon-Wiener diversity index, Evenness uniformity index, Simpson dominance index and Patrick rich index showed both bacterial diversity and the evenness of bacterial community were increased from10days to more than a year after the oil spill in Dalian Bay, indicating the self-restoration ability of this area is good. On the contrary, large but unstable microbial diversities were found in Inscriptions Beach samples after the oil spill. The evenness of bacterial community also decreased, which suggests the influence of oil spill still remains in Inscriptions Beach. These differences between Dalian Bay and Inscriptions Beach may due to their geographic position and environmental situation before the oil spill.3. Some oil-degradation related species, such as Flavobacterium in Dalian Bay, alpha proteobacterium, beta proteobacterium, gamma proteobacterium, delta proteobacteria and flavobacterium in Inscriptions Beach, appeared to be dominant bacterial communities after oil spill. Additionally, Bacteroidetes bacterium located in mammalian intestine became to be dominant bacterial community in Inscriptions Beach, indicating an increasing domestic pollution in this area.