Dynamics of bacterial community during the bloom caused by Skeletonema costatum and Akashiwo sanguinea in Xiamen sea area

Abstract:

Abstract:［Objective］To investigate the dynamics of bacterial community in Xiamen sea during the bloom mainly caused by Skeletonema costatum and Akashiwo sanguine in August 2011． ［Methods］Bacterial community structures of samples from two bloom sites and one non-bloom site were evaluated by PCR-DGGE ( Denaturing gradient gel electrophoresis，DGGE)．The genetic diversity of bacterial community was analyzed based on the DGGE fingerprint． The correlation between bacterial community and environmental parameters was studied by Canoco． ［Results］The bacterial community was largely related to pH and N /P during the start-up stage of the bloom; while in the demise stage，it was mostly correlated to salinity and temperature． According to the results of sequence analysis of DGGE dominant bands，Gammaproteobacteria accounted for 47. 7% during the bloom and Pseudoalteromonas，Pseudomonas，Alteromonas，Hydrogenophaga，Actibacter and Oleibacter were dominant genus in bacterial community． The Shannon-Weaver diversity index showed that the diversity of bacterial community in bloom site increased firstly and then decreased during this bloom．Hydrogenophaga was dominant in the start-up stage of bloom，while Pseudomonas and Pseudoalteromonas were dominant in the demise stage of bloom． The diversity of attached bacteria and free-living bacteria in bloom sites reached maximum in the same day ( the concentration of algae was high)，both of them changed greatly during the bloom while the environment factors which correlated with the two communities were different． ［Conclusion］It is the first report about dynamics of bacterial community during the bloom caused by several algae together． This work is helpful to understand the dynamics of bacterial community during the bloom，and provides a theoretical basis for bloom's control in the future．