Study On The Growth Characteristics And Nitrogen And Phosphorus Utilization Of Chlorella Vulgaris And Ootheca Bojiensis

Water eutrophication has become a worldwide problem,seriously affecting people's production and life,and even endangering human health.In recent years,water blooms due to eutrophication have occurred frequently in China,and the Algae Toxins Secreted by some algae will cause problems to the drinking water of the residents near the waters.Many methods have been studied to control the eutrophication of water body.It has been reported that appropriate algae can absorb excessive nutrients in water body to improve water eutrophication.In this experiment,the growth characteristics of Chlorella vulgaris and oocysts in eutrophic water with different concentrations of nitrogen and phosphorus,such as algal density,specific growth rate,chlorophyll a content,and the absorption and utilization of nitrogen and phosphorus nutrients were studied respectively,and the absorption efficiency of nitrogen and phosphorus in water was evaluated,which is helpful to form the ecological concept of nitrogen and phosphorus removal by suspended algae,so as to provide reference for water quality control in eutrophic water restoration It can provide theoretical and practical reference for the sustainable development and utilization of fisheryIn this experiment,Chlorella vulgaris and Oocystis borgei were selected as the research object,and the initial density of inoculated algae was 1 × 105 cells / ml-1.The effects of different nitrogen and phosphorus contents on the growth and nitrogen and phosphorus uptake of Chlorella vulgaris vulgaris were studied.There were 15 groups with different nitrogen and phosphorus contents: 0.2:0.025,0.8:0.1,1.6:0.2,0.4:0.025,1.6:0.1,3.2:0.2,0.8:0.025,3.2:0.1,6.4:0.2,1.6:0.025,6.4:0.1,12.8:0.2,3.2:0.025,12.8:0.1,25.6:0.2.There were three replicates in each group,and the culture experiment lasted for 8 days in the incubator.The main results are as followsThe experiment results of Chlorella vulgaris showed that,under low phosphorus concentration,the average specific growth rate and chlorophyll a content of 0.8:0.025 group were the highest and significantly higher than other groups(P < 0.05);the average specific growth rate and chlorophyll-a content of group 3.2:0.1 were the highest and significantly higher than those of other groups(P < 0.05);the average specific growth rate and chlorophyll-a content of group 6.4:0.2 were the highest and significantly higher than those of other groups under high phosphorus concentration.Nitrogen and phosphorus absorption efficiency: under low phosphorus concentration,the absorption rate of phosphorus in 0.8:0.025 group was the highest and significantly higher than other groups(P < 0.05);in medium phosphorus concentration,the phosphorus absorption rate of 0.8:0.1 group and 3.2:0.1 group had no significant difference(P > 0.05),but it was significantly higher than other groups(P < 0.05);in high phosphorus concentration,the phosphorus absorption rate of 1.6:0.2 group and3.2:0.2 group had no significant difference(P > 0.05)But it was significantly higher than other groups(P < 0.05).Under the medium phosphorus concentration,the phosphorus absorption rate of 1.6:0.1 group and 3.2:0.1 group was the highest and significantly higher than other groups(P < 0.05);at high phosphorus concentration,the phosphorus absorption rate of 6.4:0.2 group was the highest and significantly higher than other groups(P < 0.05).The results showed that the growth performance of Chlorella vulgaris vulgaris was the best when the ratio of nitrogen to phosphorus was32:1,and the utilization rate of nitrogen and phosphorus was the highest.The experiment results of Oocystis borgei showed that,the average growth rate and chlorophyll-a content of 3.2:0.025 group were the highest and significantly higher than other groups(P < 0.05);the average growth rate and chlorophyll-a content of12.8:0.1 group were the highest and significantly higher than those of 0.8:0.1 group,1.6:0.1 group and 3.2:0.1 group(P < 0.05);the average growth rate and chlorophyll-a content of 12.8:0.2 group were the highest and significantly higher than those of the other groups under the high phosphorus concentration(P < 0.05)It was higher than other groups(P < 0.05).There was no significant difference in nitrogen absorption rate between 0.2:0.025 group and 0.4:0.025 group under low phosphorus concentration(P >0.05),but it was significantly higher than other groups(P < 0.05);the nitrogen absorption rate of 0.8:0.1 group and 1.6:0.1 group had no significant difference(P >0.05),but it was significantly higher than other groups(P < 0.05);in high phosphorus concentration,the nitrogen absorption rate of 1.6:0.2 group was significantly higher than that of other groups Other groups(P < 0.05).Under low phosphorus concentration,the phosphorus absorption rate of 0.8:0.025 group,1.6:0.025 group and 3.2:0.025 group were 100% and significantly higher than other groups(P < 0.05);the phosphorus absorption rate of 6.4:0.1 group and 12.8:0.1 group were 100% and significantly higher than other groups(P < 0.05);the phosphorus absorption rate of 12.8:0.2 group was100% and significantly higher than other groups(P < 0.05).