The Correlation Analysis Between The Bacterial Communities Of Ecosystem And Environmental Factors In Typical Shore-based Sea Cucumber(apostichopus Japonicus) Aquaculture Pond In Northern China

In this study,the typical shore-based semi-opened sea cucumber culture ponds in northern China were used as the research object.With the 16S rRNA sequencing technology,the diversity characteristics and the abundance of water,sediment and intestinal flora of Apostichopus japonicus of Liaoning Changhai,Liaoning Yingkou,Hebei Laoting and Weihai Rushan are analyzed in different seasons.At the same time,RDA analysis was used to explore the main environmental factors affecting the ecological environment of the sea cucumber pond and the structure of the intestinal flora of Apostichopus japonicus.The aim of this study is to have a more comprehensive and in-depth understanding of the ecological structure of the sea cucumber pond and the structural characteristics of the intestinal flora of the Apostichopus japonicus,which can provide a theoretical basis for the healthy breeding and disease prevention and control of Apostichopus japonicus.The main research results are as follows:1.The correlation analysis between the structural characteristics of water flora and the environmental factors in typical shore-based sea cucumber aquaculture pond in northern China.The 16S rRNA sequencing technology was used to analyze the structural characteristics of water body flora of Apostichopus japonicus in different seasons and regions.The results showed that the diversity and abundance of the flora in the water was highest in summer and lowest in autumn.Among the water bodies of sea cucumber in different seasons and regions,Proteobacteria is the first dominant bacteria,and the relative abundance is above 49.48%.In addition,both the Bacteroides and Actinomycetes were detected as dominant bacteria in different seasons of aquaculture,and the relative abundance of the dominant bacteria changed significantly with seasonal changes.Planktotalea,Sulfitobacter,Candidatus Pelagibacter,Tateyamaria,Marivita,Celeribacter,Litoreibacter,Planktomarina,Roseibacillus,Cellulophaga,Psychrobacter,Pseudoalteromonas and Olleya are the main dominants bacterial genera in different seasons.The results of RDA analysis showed that there was a good correlation between environmental factors and water body structure of aquaculture pond.The environmental factors which influence the structure of water bodies are similar.The main are salinity,sulfide,TP and PO₃-P.2.The correlation analysis between the structural characteristics of sediments and environmental factors in typical shore-based sea cucumber aquaculture pond in northern China.The 16S rRNA sequencing technology was used to analyze the structural characteristics of sediments in the ponds of Apostichopus japonicus cultivation in different seasons and regions.The results showed that the diversity and abundance of the microbial communities in the sediments were highest in summer and lowest in autumn,which was consistent with the seasonal variation of water flora diversity.The dominant bacteria of sediments are Proteobacteria,Bacteroides,Verrucomicrobia,Actinobacteria,Planctomycetes and Chloroflexi.Among them,Proteobacteria is the first advantage in sediments in different seasons.The relative abundance of the bacteria is above 46.33%.In addition,Aminicenantes,Ignavibacteriae,Latescibacteria,Chlamydiae,and other rarely reported bacteria are also detected.From the view of genus level,Desulfopila,Exiguobacterium,Sulfurovum,Citrobacter,Acinetobacter,Thioprofundum,Burkholderia,Desulfosarcina,Lutimonas,Mesorhizobium,Salinimicrobium,Clostridium sensu stricto,Arcobacter,Pseudoalteromonas,Psychrobacter and Halolactibacillus are dominant bacterial genera,which have significant difference in different seasons.The results of RDA analysis showed that DO,COD,NH₄-N,pH,TOC and T were the main environmental factors affecting the structure of the sediment microbial communities in the sea cucumber culture ponds.3.The correlation analysis between the structure of the intestinal flora of Apostichopus japonicus and the environmental factors in typical shore-based sea cucumber aquaculture pond in northern China.The 16S rRNA sequencing technology was used to analyze the structural characteristics of the intestinal flora of Apostichopus japonicus cultivation in different seasons and regions.The results showed that the diversity and abundance of the intestinal flora was highest in winter and lowest in autumn.Proteobacteria is the first dominant bacterium in the different seasons,which is consistent with the results of water and sediment studies.With the change of season,the relative abundance of Proteobacteria increase from 55.11%-67.66%to 81.69%-98.99%.Additionally,the remaining dominant bacteria such as Verrucomicrobia,Bacteroidetes,Planctomycetes,and Firmicutes have significant seasonal changes.From the view of genus level,dominant bacterial genera include Desulfopila,Halioglobus,Enterococcus,Sulfurovum,Haliea,Acinetobacter,Lutibacter and Pseudomonas.RDA analysis showed that the structure of the intestinal flora in spring,summer and winter was similar.Sulfide,NH₄-N,TN and salinity were the main physical and chemical factors affecting the structure of the intestinal flora of Apostichopus japonicus.4.The correlation analysis of microbial communities of different environmental medium in typical shore-based sea cucumber aquaculture pond in northern China.From the result of correlation analysis of different environmental medium groups in sea cucumber culture ponds,it showed that from the three mediums of water,sediment and gut,the eight species of the top ten relative abundances bacteria were common bacteria,respectively Proteobacteria,Bacteroidetes,Actinobacteria,Verrucomicrobia,Firmicutes,Planctomycetes,Chloroflexi and Acidobacteria.LEfSe analysis showed that the water-specific flora mainly belongs to Proteobacteria and Bacteroidetes;The sediment-specific flora mainly belongs to Chloroflexi,Firmicutes,Acidobacteria,Aminicenantes,Deferribacteres,Fusobacteria and Thenmotogae;Intestinal-specific flora mainly belongs to Proteobacteria,Firmicutes,Planctomycetes and Chlamydiae.Through this study,it was found that there is a correlation between the flora structure of the Apostichopus japonicus culture environment and the intestinal flora of the Apostichopus japonicus,and it has certain relative independence.