Effect of macrobenthos on nitrogen transformation in mud-water system
In order to explore the effects of macrobenthos on nitrogen content and occurrence forms in the mud-water system,a simulated ecosystem was constructed with the help of Cipangopaludina chinensis and Misgurnus anguillicaudatu to analyze the change characteristics of environmental factors such as DO,COD,TOC and organic matter in the mud-water system,and to explore the transformation of nitrogen content and nitrogen occurrence forms.Pearson correlation analysis was used to identify the key environmental factors affecting nitrogen conversion.The experimental results showed that DO decreased by 51.56%~54.10%and COD increased by 50.41%~81.32%in the reactor with macrobenthos compared with the control group.The life activities of macrobenthos increased the content of TN and NH3—N in overlying water by 2.92~6.50 times and 12.93~18.98 times,respectively,while NH3—N in bottom mud only increased by 0.61~0.87 times.Macrobenthos decompose organic nitrogen through life activities such as feeding,digestion and respiration,promote the conversion of OSF—N to other forms of nitrogen,and reduce the proportion of OSF—N in TN.According to Pearson correlation analysis,TOC and DO were the key environmental factors affecting nitrogen conversion.