DRP003634
Evidence  of  bacterioplankton community adaption in responses to  long-term mariculture disturbance
Mariculture activity acts as a disturbance to bacterioplankton community because it results in coastal eutrophication known to alter the bacterial composition. However, to what extent that such disturbance affects turnover of bacterioplankton community composition (BCC) and network interactions among bacterial assemblages are largely unknown. To this end, using 454  pyrosequencing of bacterial 16S rRNA gene, we evaluated the effects of mariculture disturbance on the temporal dynamics of BCC in Xiangshan Bay, the East China Sea. Clearly seasonal succession and sites (fish farm and control sites) separation of BCC were observed, which follow the time-decay for similarity  relationship.  Sampling  time  and mariculture  disturbance  respectively contributed 19.3% (P = 0.001) and 4.3% (P = 0.008) variations of the BCC. However, seasonal dynamics of bacterial alpha-diversity had no obvious trend, but were tightly associated with the relative abundances of potential bacterial predators. The temporal succession of the  BCC was significantly correlated with seawater temperature, chemical oxygen demand, N/P  ratio, dissolved inorganic nitrogen and chlorophyll a. We observed over the three seasons the  same change pattern for a few dominant bacterial families under mariculture disturbance. Additionally, mariculture disturbance considerably decelerated the temporal turnover rate, but  intensified the network interactions of bacterial community. These results demonstrate that BCC is sensitive to mariculture disturbance in this study region, while the consistency with which sensitive bacterial assemblages could characterize such disturbance. Low temporal turnover rate and complex network interactions, thus enabling bacterial communities were adaptive to long-term mariculture disturbance.