Corbicula Fluminea Improve Eutrophic Water Quality And Ecological Significance

Based on the collection and sorting of data, analysis and simulation of field controlled ex periment in Taihu Lake, effects of filter-feeding by C.fluminea on improvement of eutrophic water quality, controlling of exogenous nutrient and adjustment between water- sediment cou pling relationship were studied in my paper. At the same time, this paper aimed at revealing re sponses of submerged plant growth to the filter-feeding of C.fluminea and to provide theoretic al basis for the ecological restoration of shallow lakes. The results were as follows:A controlled experiment was conducted to assess the effects of C.fluminea on water quali ty improvement with four treatments. The results showed that C.fluminea can decrease chlor ophyll a concentrations significantly in low, medium and high density treatments by 23.29 %, 48.32 % and 71.17 % respectively. Meanwhile, TN and TP concentrations of water also reduc ed significantly with C.fluminea treatments.Effect of C.fluminea on exogenous nutrient control The results showed that external nutri ent promoted the growth of algae and chlorophyll a concentration significantly. However, the filter-feeding of C.fluminea and biological sedimentation may decrease nutrients and the chlor ophyll a concentration, which may reduce the pressure on the lake eutrophication.Effect of C.fluminea on water-sediment coupling relations The experimental results sho wed that filter-feeding pressure of C.fluminea would lead to lower nitrogen and phosphorus c oncentrations in different level. At the early stage of the experiment, TN and TP concentration with C.fluminea group were obviously lower than the control group, and there were no signifi cant differences between treatment groups. At the late stage of experiment, the TN and TP co ncentration of control were still higher than the treatment groups, but the TN and TP concentr ation of none C.fluminea removed group were high than other treatment groups.Effect of filter-feeding by C.fluminea on the growth of submerged plant Results showed that relative growth rate increased along with the C.fluminea density, where the growth rate a nd C.fluminea density were positively correlated. Filter-feeding phytoplankton by C.fluminea made water physical and chemical environment conducive to submerged plants, which may b e influenced by the underwater light conditions.