Dynamic rules for some environmental factors in the simulative experiment of phosphorus exchange at sediment-water interface

Some environmental factors were dynamically monitored and their relationships among the factors in different layers were analyzed in the simulated experiment of phosphate transferring at sediment-water interface. The dynamics of dissolved oxygen (DO), conductivity (Cond.), pH and oxidation reduction potential (ORP) at the different layers of water column and sediment in the simulated system were detected continuously with a set of instruments such as rhizon soil moisture sampler. The relationships and interactions among the different parameters in the different layers were analyzed. The results indicated that DO concentration in bottom water column was lower than that in middle and upper layers; there were no significant differences among the conductivity of different layers in overlying water and conductivity increased linearly with time; pH dynamics had significant spatial variability in the system, the sediment-water interface was jump point, changes of pH in overlying water lagged behind in the sediment porewater; ORP in the sediment was lower than in overlying water and the sediment-water interface was the jump point. DO concentrations were positively correlated with ORP in upper sediment and every layer in overlying water, but not related to ORP in bottom porewater. The interactions among other parameters were not significant.