Spatio-temporal changes of bacterioplankton communities in Litopenaeus vannamei desalinated ponds and their responses to physicochemical factors

The regulation of bacterioplankton is the core content of the environmental control strategy in shrimp aquaculture. Exploring the general rules of the construction of bacterioplankton community can further promote the research on water quality regulation for shrimp ponds. Using 16s rRNA high-throughput sequencing technology, we conducted 12 weekly surveys in Litopenaeus vannamei desalinated ponds.The results indicate that a total of 2 854 OTUs (97% similarity) were obtained from 48 samples (Archaea belonged to 2 phyla, 1 class, 1 family and 1 genus; and bacteria belonged to 30 phyla, 59 classes, 98 orders, 199 families and 433 genera, among which 25 genera were dominant flora). The dominant flora had high similarity in the composition, but with great differences in the distribution and relative abundance in each pond. The total average phylogenetic diversity index was 77.57, ranging from 24.39 to 111.65; the total average Shannon diversity index was 3.96, ranging from 2.64 to 5.06; the total average species richness index was 716, ranging from 229 to 1 054. NMDS analysis shows that the community structure of bacterioplankton in each pond varied greatly at the early stage of aquaculture, but not so greatly at the middle and late stages. The results of redundancy analysis shows that the labile phosphorus, total alkalinity, dissolved oxygen and sulfide were the main environmental factors affecting the distribution characteristics of community structure of bacterioplankton.