| At present,polyculture is the one of the main ways in freshwater aquaculture in China,but the density and feeding rate in the breeding is high,resulting in increasing the content of nitrogen and phosphorus in aquaculture ponds,causing frequent deterioration of water quality,disease,seriously restricts the sustainable development of aquaculture.As a kind of friendly treatment method,biofilm is widely used in domestic sewage and industrial sewage treatment,and the treatment of aquaculture wastewater is mostly carried out in the laboratory simulation experiment,research in pond ecosystems is not deep.So the running mechanism of biofilm polyculture pond ecosystem and biofilm microbial characteristics of understanding is not clear,so to carry out farming pond biofilm microbial species,community structure and function study on metabolic characteristics,and the dominant bacteria potential and possible to strengthen measures to improve the efficiency of nitrogen removal and biological membrane method the important significance of strengthening technology.This study used Biolog-ECO and high-throughput sequencing analysis in the process of biofilm formation(0~9w)attachment of microorganisms,biofilm community structure and function changes of metabolic characteristics in the Southern China area of high-yield polyculture pond,and study the change of water quality and microbial community,the main results are as follows:The change of water quality index was studied and the community succession of microbial community attached to biofilm carrier was studied by high-throughput sequencing.The results showed that:Providing artifcial substrata effectively reduced the concentrations of total nitrogen and total phosphorus in the pond.Relatively stable microbiota was formed after approximately 1 week.The dominant phyla in the mature bioflm were Proteobacteria,Bacteroidetes,Firmicutes and Actinobacteria.The relative abundances of denitrifers and phosphorus-removing bacteria,such as those in Comamonadaceae and Neisseriaceae,were signifcantly increased.The use of avermectin B1 changed the community structure of the microbiota;the microbiota were more similar to those at Week 0 than to those at Week 3.However,the microbial community structure recovered after approximately 1 week.Using the Biolog-ECO technique to analyze the microbial carbon metabolism in theprocess of biofilm formation(0w~9w),the results show that: During the test,the concentration of TN and TP were respectively decreased from 7.45 mg/L and 1.69 mg/L to0.66 mg/L and 0.25 mg/L,but the removal rate respectively rised to 91.14% and 91.14%;For different sampling time point,the metabolic activity of ulitizing carbon source exists obvious difference: 3,5,7,8 w biofilm metabolic activity at high levels;In the biofilm formation process,the trend of the biofilm microbial metabolic activity appears the rise and then reduced;Richness index,Shannon index,Simpson index,and Mc Intosh index performance for 3,4,5,7,8 w is significantly higher than other weeks;the source utilization of six kinds of carbon carbohydrates and polymer class has the highest utilization rate;Along with the formation of the biofilm,adherent microbes of glycogen are increased obviously,N-Acetyl-D-Glucosamine,?-Methyl-D-Glucoside,?-D-Glucose-1-Phosphate utilization of carbon sources,such as;(4)biofilm microbial metabolic characteristics of principal component analysis(PCA)shows that the different sampling time point of samples gathered in three different areas,including 3,4,6,8,9w microbial metabolic difference is small,0w and 1w as a whole,5w and 7w as a whole,but there were significant differences between the three concentrated areas. |
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