Qunhe Wu1, Renduo Zhang, Shan Huang, Hengjun Zhang. 1. School of Environmental Science and Engineering, Sun Yat-Sen (Zhongshan) University, Guangzhou 510275, China. eeswqh@mail.sysu.edu.cn
Abstract
To better understand the mechanisms of eutrophication, we addressed the microbial processes that influence many key aspects of water-sediment systems. In this study, a large column experiment was conducted for 30 d. Along the column, solution samples were collected at different locations at different time. The samples were analyzed for physical, chemical, and biological properties of the sediment and overlying water. The results showed that the amount of nitrogen transforming bacteria was higher than that of phosphorous bacteria. The amount of nitrogen transforming bacteria was in the order: ammonifier > denitrifying bacteria > nitrobacteria and nitrosomonas. Principal component analysis indicated that the three main factors accounted for more than 90% overall contributions for bacterium growth, which represented nutrition, organics and oxygen, and pH and redox potential (Eh) of the environment. Corresponding to the bacteria, the concentrations of nitrogen in the system was in the order: ammonia (NH4(+)-N) > nitrate (NO3(-)-N) > nitrite (NO2(-)-N). The fluxes of N and P clearly showed a temporal release and adsorption processes in the water-sediment system. The large magnitude of N fluxes suggested that N might act as an important contamination source for the water quality. However, P exchange between the sediment and overlying water was less intensive during the experiment.
To better understand the mechanisms of eutrophication, we addressed the microbial processes that influence many key aspects of n class="Chemical">water-sediment systems. Inpan> this study, a large column experiment was conducted for 30 d. Along the column, solution samples were collected at different locations at different time. The samples were anpan>alyzed for physical, chemical, anpan>d biological properties of the sediment anpan>d overlying pan> class="Chemical">water. The results showed that the amount of nitrogen transforming bacteria was higher than that of phosphorous bacteria. The amount of nitrogen transforming bacteria was in the order: ammonifier > denitrifying bacteria > nitrobacteria and nitrosomonas. Principal component analysis indicated that the three main factors accounted for more than 90% overall contributions for bacterium growth, which represented nutrition, organics and oxygen, and pH and redox potential (Eh) of the environment. Corresponding to the bacteria, the concentrations of nitrogen in the system was in the order: ammonia (NH4(+)-N) > nitrate (NO3(-)-N) > nitrite (NO2(-)-N). The fluxes of N and P clearly showed a temporal release and adsorption processes in the water-sediment system. The large magnitude of N fluxes suggested that N might act as an important contamination source for the water quality. However, P exchange between the sediment and overlying water was less intensive during the experiment.