Phosphorus removal from water of eutrophic Lake Donghu by five submerged macrophytes

Five submerged macrophytes, Ceratophyllum demersum, Elodea canadensis, Potamogeton crispus, Myriophyllum spicatum and Vallisneria spiralis were selected and their relative growth rate (RGR) and the capacity of removing phosphorus in greenhouse were evaluated by hydrotropic experiments of two seasons (spring and autumn). The results showed that the RGR of C. demersum was the highest (1.29 for spring and 0.58 for autumn) among the five macrophytes, while that of P crispus was the lowest (0.039) in the spring experiment and M. spicatum was the lowest (0.022) in the autumn experiment. Also, total phosphorus (TP) removal rates of C. demersum (91.75% and 92.44%) during the spring and autumn were the highest in the five macrophytes. Among the five macrophytes, the order of phosphorus removal capacities was: C. demersum > E. canadensis > P. crispu during the spring. But for autumn, the order was C demersum > V spiralis > M. spicatum.