| Penaeus Vannamei has become one of the main cultured aquaculture species in China due to its characteristics of fast growth,strong disease-resistant ability and low nutrition requirement.Macrobrachium rosenbergii is a worldrenowned freshwater prawn species which has the advantages of large size,short growth cycle,wide feeding habits,easy-breeding,delicious meat and relatively high economic value,so it becomes one of the special aquatic products with good development prospect.From April to June in 2016,the ponds' water were sampled every 5 days and sediment sampled once at the end of experiment in 7 Penaeus Vannamei cultivation ponds of a cooperativein Shanghai Fengxian district.Water quality in ponds were analyzed and also microbial communities of pond water and sediment.The change regulation of water quality and microbial communities were described and the relevance between environment factors and microbial communities were analyzed.From December 2014 to March 2015,a biological filter was set up to constitute a recirculation system of the Macrobrachium Rosenbergii OverWintering pond in an aquatic company which is located in Shanghai Jinshan district.The water in the pond was pumped out and transferred to the top of recirculation system,then flowed down through the suspended nano fiber membrane to the bottom of the filter and finally the bottom outlet re-entered the Over-Wintering pond.High throughput Miseq sequencing technology was used to investigate microbial community divers ity of pond water,surface membrane on artificial aquatic plants in ponds and nano fiber membrane in external biofilter.Water quality was monitored periodically with conventional water quality detection methods.The results of water quality in Penaeus Vannamei cultivation ponds were as follow:The average of p H,DO and T was(8.00±0.30),(6.76 ±1.41)mg·L-1 and(25.9±2.91)?,respectively,which fit the growth requirements of Penaeus Vannamei.Significance difference analysis between groups showed that COD,TAN and TN had no significant difference among cultivation ponds during culture period(p>0.05).NO2--N,NO3--N,TP and AP had highly significant difference among ponds during culture period(p<0.01).The average value of TAN in ponds NO.4,5,6,7,8,12 and 13 was(0.88±0.55),(0.84±1.00),(1.07±0.87),(0.87±0.69),(0.74±0.48),(0.65±0.50)and(0.76±0.56)mg·L-1,respectively.The average of NO2--N in ponds NO.4,5,6,7,8,12 and 13 was(0.24±0.16),(0.32±0.22),(0.44±0.17),(0.17±0.26),(0.28±0.24),(0.20±0.19)and(0.18±0.21)mg·L-1.The experiment also found that TP and AP was low in each cultivation pond.The concentration of TP and AP in ponds NO.4,5,6,7,8,12 and 13 was(0.06±0.04),(0.17±0.10),(0.17±0.12),(0.12±0.07),(0.13±0.05),(0.09±0.06),(0.09±0.05)mg·L-1 and(0.01±0.001),(0.07±0.10),(0.09±0.11),(0.02±0.01),(0.03±0.02),(0.02±0.01)and(0.02±0.01)mg·L-1 in turn.The pond water quality met the growth requirement of Penaeus Vannamei.p H and DO was 7.64±0.31 and 6.01±0.31 mg·L-1 in Macrobrachium rosenbergii over-wintering cultivation pond.The average values of COD,TAN and NO2--N were(4.17±2.06)mg·L-1,(0.25±0.15)mg·L-1 and(0.16±0.07)mg·L-1.Water quality of over-wintering cultivation pond was maintained at a good state and reached a relative steady state after operating recirculation aquaculture system for 40 days.The Macrobrachium rosenbergii over-wintering cultivation pond water quality maintained at a good state due to the recirculation system composed of suspended artificial aquatic plants and the external biofilter.High throughput Miseq sequencing technology was used to investigate microbial community divers ity of water and sediment in Penaeus Vannamei cultivation ponds,and diversity of the pond water,biomembrane samples on fiber of the artificial plants and nano fiber of the external biofilter.The results were as follow:In Penaeus Vannamei cultivation pond water and on the level of genus,812 species were identified which belonged to 39 phylum.Un-identified species accounted for 29% of the total microbial community.On the level of genus,taking the abundance of >0.1% as standard,85 genus were obtained which accounted for 65% of the total microbial community.On the level of phylum,taking the abundance of >0.1% as standard,9 phylum were obtained including Proteobacteria,Actinobacteria,Cyanobacteria,Bacteroidetes,Firmicutes,Chlorobi,Acidobacteria,Chloroflexi,Gemmatimonadetes.Proteobacteria,Actinobacteria,Cyanobacteria and Bacteroidetes were the absolutely dominant microbial communities which accounted for 60%,16%,10% and 9%,respectively.Firmicutes and Chlorobi were the relatively dominant which accounted for 3% and 1%.Proteobacteria,Actinobacteria,Bacteroidetes,Firmicutes and Cyanobacteria were the common dominant microbial community in each cultivation pond.Tenericutes,Elusimicrobia and Spirochaetes was unique microbial community in pond No.4,5 and 8,respectively.In Penaeus Vannamei cultivation ponds,on the level of genus,819 species were identified in sediments which belonged to 50 phylum.Un-identified species accounted for 31% of the total microbial community.On the level of genus,taking the abundance of >0.1% as standard,131 genus were obtained which accounted for 59% of the total microbial community.On the level of phylum,taking the abundance of >0.1% as standard,16 phylum were obtained including Proteobacteria,Bacteroidetes,Firmicutes,Acidobacteria,Gemmatimonadetes,Actinobacteria,Chlorobi,Tenericutes,Nitrospirae,Fibrobacteres,Spirochaetes,Verrucomicrobia,Cyanobacteria,Elus imicrobia,Chloroflexi and Fusobacteria.Proteobacteria,Bacteroidetes,Firmicutes were the absolutely dominant and accounted for 46%,17% and 16%,respectively.Acidobacteria,Gemmatimonadetes,Actinobacteria and Chlorobi were relative ly dominant and accounted for 3.8%,3.1%,3% and 1%.Proteobacteria,Bacteroidetes,Firmicutes,Acidobacteria,Actinobacteria and Gemmatimonadetes were the common dominant microbial community in each cultivation pond.Heat map and bar chart of species composition indicated that Proteobacteria,Actinobacteria and Bacteroidetes were absolute ly dominant during the cultivation process.Cyanobacteria had a dominant position in the middle of the cultivation process.On the level of genus,the dominant genus varied as time and cultivation condition changed.As a whole,the absolute dominant microbial community had a great contribution to the composition of microbial communities,while the microbial community which had a tiny richness could not be neglected either.CCA was used to analyze the correlation between water quality and microbial communities in pond water,water quality and microbial communities in pond sediment.The results showed that DO,p H,COD,TN had a relatively great effect on microbial communities in pond water,and p H showed a greater effect.Temperature,ALK,AP,NO3--N had a relatively great effect on microbial communities in pond sediment,and among which temperature showed a greater effect.High throughput Miseq sequencing technology was used to investigate microbial community divers ity of pond water,artificial aquatic plants which were composed of normal fiber membrane and nano fiber membrane in external biofilter.Water quality was monitored periodically with conventional water quality detection.Bacteria composition and community divers ity varied in three substrates and 64 species were identified which belonged to 64 genus and 9 phylum including Proteobacteria,Actinobacteria,Bacteroidetes,Chloroflexi,Firmicutes,Planctomycetes,Nitrospirae,Acidobacteria and Chlorobi.On the level of genus,Comamonadaceae_unclassified was the most dominant genus in pond water which both appeared in the other two substrates.Inhella dominated in surface of normal fiber while Fusibacter was predominant in nano fiber membrane surface.Nano fiber membrane had the highest bacteria community divers ity,followed by normal fiber membrane and pond water. |
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