Preliminary Study On The Impact Of Microbial Agents On Aquaculture Water Quality And Microbial Community Structure

Aquaculture is under the control of human breeding, cultivation and harvest of aquatic animals and plants production. While the world fresh water and marine aquaculture still has such huge potential for development, but has encountered very serious water pollution problem and began to restrict its own development.We build a model of aquaculture water; four strains of bacteria on the water quality of aquaculture water purification mechanism were studied by chemical indicators of water quality monitoring and 16S rDNA-PCR technology. Specific studies are as follows:(1) The impacts of the four strains----photosynthetic bacteria, Bacillus subtilis, Lactobacillus casei and Bacillus pumilus microbial agents on the aquaculture water quality have been studied separately.Results show that the impact of four agents can affect nitrogen significantly. Bacillus subtilis and Lactobacillus casei will make the TN increased in the whole experiment; four strains in the varying degrees decreased NO2-, were relatively consistent 45% or more; after adding these four strains, the NO3- of water were all first increased then decreased, and photosynthetic bacteria NO3- maximum decline was about 90%; Bacillus subtilis and Lactobacillus casei in the investment increased water NH4+ shortly after dosing then immediately reduced and eventually reached the relative decline of 83.8% and 73% separately.To the water phosphorus, in addition to the Bacillus subtilis experiment TP and SOP will be increased water content, the other 3 strains could reduce the phosphorus content, and their relative decline of TP were 55% less. Bacillus pumilus can effectively reduce the SOP, can reach 93.1%.Photosynthetic bacteria and Lactobacillus casei enhanced the pH value fluctuation in a short time, and the range under 3%. In addition, with the exception of Bacillus subtilis had no effect on the COD, the other 3 strains could reduce the COD content of different degree, in which photosynthetic bacteria and Bacillus pumilus strongest reduction of COD.(2) Got the optimal dosing concentration of photosynthetic bacteria and Bacillus subtilis.Photosynthetic bacteria's, optimal dosing concentration is 104 bacteria/mL; when dosing concentration of Bacillus subtilis is 10 bacteria/mL were best for removal of nitrogen, but if the primary purpose is reducing COD it should be 105 bacteria/mL.(3) The impact after dosing 104 bacteria/mL photosynthetic bacteria on the microbial population has been studied.DGGE electrophoresis analysis showed that photosynthetic bacteria increased the types of microorganisms in water; and species richness curve also showed that adding photosynthetic bacteria can significantly increase the microbial diversity of water. Thereby, adding agents can enhance the water resistance and its ability to repair itself.