Bioremediation Of Sediment And Water In White Prawn Ponds By Rotation Of White Prawn Culture And Vegetable Cultivation

In this paper,the changes of nutrient elements such as nitrogen and phosphorus in sediment and physical and chemical indexes in water were detected and analyzed during the rotation of Litopenaeus vannamei culture and vegetable cultivation.The effects of sediment on water quality were explored by indoor simulation experiments.To provide data for improving the aquaculture environment and improving the utilization rate of ponds.The main results are as follows:1.During white prawn culture,the pH DO、TP、NH3-N、TN、NO3--N、NO2--N index of rotation pond is relatively stable compared with that of Traditional white prawn culture pond,and the number of Vibrio in rotation pond is also lower than that of Traditional white prawn culture pond.2.The removal rates of TP,TN,TC and TS by vegetable tillage were 80.4%,81.3%,73.7% and 53.3% respectively,which were significantly higher than those in the dew and flooded areas of the two ponds,and the number of Vibrio in the tillage area remained at a very low level throughout the whole tillage process.The redox potential in the tillage area of the rotation pond increased rapidly from-201 mV to 200 mV two months after white prawn harvest.3.High-throughput sequencing of sediments in different regions revealed that there were small differences in diversity and abundance among dominant groups of bacteria at phylum classification level and class classification level,and significant differences in diversity and abundance at genus classification level,with the most bacterial species associated with N,P and S element cycling found in tillage areas.4.The simulation experiment found that the microbial community in sediment could directly affect the microbial community structure of water body,and the most obvious difference was the number of vibrio.The number of vibrio in the flooded area of white pond was more than 6 times higher than that in the tillage area of rotation pond in 20 days,and other water quality indicators except TN showed significant differences(p >0.05).Through high-throughput sequencing,it was found that there were 7 dominant bacterial taxa in the four groups of soil samples in the simulation experiment.The dominant species among the four groups were similar,but the abundance of eachbacteria was different.Proteobacteria was the absolute dominant group in all samples,and its abundance ranged from 33% to 84%.There are 9 dominant classes of common bacteria.Gamma Proteobacteria is the absolute dominant group.Its abundance ranges from 22.9% to 77.2%.The number of dominant classes in water decreases with the increase of test time.There are 5 dominant classes of common bacteria,and the difference between groups at the genus level is more obvious.