Bacterial Community Composition In The Sea Studied By PCR-Denaturing Gradient Gel Electrophoresis

Bacterial community composition and predominant bacteria were analyzed by PCR-Denaturing Gradient Gel Electrophoresis(DGGE) in hypoxia of Changjiang estuary and in the Yellow Sea Cold Water Mass(YSCWM).In hypoxia of Changjiang estuary , 25 DGGE bands reflecting varying phylotypes were excised, cloned and sequenced. Phylogenetic analysis of cloned bands shows that bacterial phylotypes were maked up by four phylums bacteria, Proteobacteria,Bacteroides,Firmicutes and Cyanobacteria. Among these sequences, 16 were related toγ-Proteobacteria andδ-Proteobacteria. By spatio-temporal comparison, bacterial community composition was different from hypoxia and non-hypoxia. The predominant bacteria was Flavobacteria in hypoxia.In the Yellow Sea Cold Water Mass, phylogenetic analysis of 24 cloned bands shows that bacterial phylotypes were maked up by two phylums bacteria, Proteobacteria and Bacteroides. Among these sequences, 16 were related toγ-Proteobacteria andδ-Proteobacteria and 3 were related to Bacteroides. By spatio-temporal comparison, bacterial community of all stations in April (the temperature of seawater was low, among 7℃-12℃) was the same as the inter of YSCWM in October(≤10℃), different from the exterior of YSCWM(≥19℃). The predominant bacteria has the same characteristic, all stations′in April same as the inter of YSCWM in October. The predominant bacteria of the exterior of YSCWM vary among different station.