Structural Analysis of Seawater Bacterial Community from Culture Pond of Apostichopus japonicus at Different Periods

This paper analyzed the bacteria community composition and variation of seawater from culture ponds of Apostichopus japonicus at Wafangdian,Dalian City,Liaoning Province. Seawater of different periods from culture ponds of Apostichopus japonicus was collected,and variable region fragments of 16 S r DNA V3 were amplified by specific primers of bacteria,and analyzed with deformation gradient gel electrophoresis( DGGE). The main bands were cut,recovered,and sequenced. The results showed that the diversity index of samples from different periods varied from 1. 994 5 to 2. 230 5,and there were not big differences in evenness. The sample richness was between 42 and 48. But there were differences between bacterial community compositions of those samples. In March and September seawater shared the highest similarity( 80%),and in June and other months,there was the biggest difference in cluster distance. Results of 39 main bands of sequences indicated that 12 bands of them were close to uncultured bacteria,1 band was close to Actinobacteridae,and 26 bands were identified as Flavobacteria,α-proteobacteria and γ-proteobacteria. Flavobacteria,α-proteobacteria and γ-proteobacteria appeared in seawater at all periods,and among them Flavobacteria was dominant with proportion of 23. 8% ~ 50. 0%. Seawater bacterial community compositions in cultured ponds at different periods were relatively stable,but there were differences in specific strains.