Effects Of Filter-feeding Mussel, Submerged Macrophyte And Their Coexistence On Eutrophication

Filter-feeding mussel and submerged macrophyte are important components of aquatic ecosystem, playing a key role in affecting the structure, function and process of shallow lakes. However, the effects of their coexistence on water environment in shallow lakes are still unclear. Mesocosm experiments(control, mussel treatment,submerged macrophyte treatment, and coexistence of mussel and submerged macrophyte treatment) were conducted to evaluate the effects of filter-feeding mussel Anodonta woodiana, submerged macrophyte Vallisneria natans, and their coexistence on water quality. Results showed that: A. woodiana decreased NO2--N concentration of water body, but it had no effect on other nitrogen and phosphorus concentrations in different forms. V. natans increased pH and decreased nutrient level of water column.TN, NO3--N, NO2--N, TP, TDP and SRP concentrations in overlying water were reduced significantly. The coexistence of the mussel and the submerged macrophtye reduced both nitrogen and phosphorus concentration in different forms. And pH of water body was increased significantly. All the treatments of mussel, plant and their coexistence decreased phytoplankton biomass, TSS concentration and loss of ignition of water column significantly. Light intensity over sediment surface in mussel treatment was higher than that of in control. So A. woodiana improved the light condition of the system and promoted growth of attached algae and benthic algae.Meanwhile, the mussel also promoted growth of V. natans. Dry biomass, root length and height of the macrophyte in mesocosm were higher with coexistence of the mussel and macrophyte than the macrophyte alone at the end of experiment.The study showed that A. woodiana, V. natans, and their coexistence can improve the eutrophication status. Their coexistence played a synergistic effect to purify water quality and was more effective in improving the status...