Study On Characteristics Of Bacterial Community Structure Of The Interfacial Water-sediment

Phosphorus is the key factor for water eutrophication. Microorganisms in the sediment play important roles in the phosphorus cycling between water and its sediment which eutrophicated.In this study, the interfacial sediment in different regions of Lake Taihu, were sampled on March, June and September2011, and the spatial and temporal distribution of the physical and chemical properties in each sampling sites were studied. Bacterial communities of sediments in different region were analysed by PCR-DGGE technology and that of3.16#sediment was analysed by16S rDNA clone library. The results showed that,(1) The spatial differences among lake areas were significant and seasonally varied with the TP、SAP、pH and alkaline phosphatase activity in overlying water and the sediment interstitial water. Contents of PW-TP and PW-SAP were higher than W-TP and W-SAP; value of W-pH were higher than PW-pH; PW-ALP activity were higher than W-ALP. In March, June and September, the content of TP, SAP, pH and ALP activity were the highest at16#site. Correlation analysis showed that W-TP was significantly correlated with W-SAP and W-pH; W-SAP was significantly correlated with PW-TP, PW-SAP, W-ALP and PW-ALP; PW-TP was significantly correlated with PW-pH, PW-SAP was significantly correlated with PW-ALP.(2) The bacterial community structure in the interfacial sediment of Lake Taihu were studied by molecular ecology methods.16S rRNA PCR-DGGE analysis showed that affected by levels of nutrition and seasonal variations, the diversity and dominant populations of bacterial community structure had a dynamically changes. Dominant DGGE band were recovered and sequencing analysed, the results show that, dominant species of the bacteria in the sediment of Lake Taihu mainly including Achromobacter, Lysobacter, Serratia, Peredibacter, Lactobacillus, Flavobacterium, Escherichia, Polaribacter and Xanthomonas et al.16S rDNA clone library was constructed using sample of sediment from3.16#site.48genotypes were identifed out of194positive clones by amplified sequence restrictive analysis. Based on sequencing data of the16S rDNA which represent for the genotypic clones, the mian species of the bacteria in the sediment including Arenimonas, Streptococcus agalactiae, Proteobacteria, Pseudoxanthomonas, Achromobacter and Brevundimonas.(3) Bacterial strains in the sediment of7#、16#and21#site of March fromTaihu Lake were isolated, the results show that aboundant bacteria present in the sediments. One strain3-wff-81was identified by polyphasic taxonomy method, and as a new species in the genus of Geodermatophilus, it was named as Geodermatophilus taihuense.