Comparative Study on Purification Characteristics of Various Submerged Macrophyte Species in Different Seasons

Based on macrophyte-buffering improvement methods, this study compared the capability of water quality purification among seven submerged macrophytes through continuous tests. No significant difference in nitrogen and phosphorus removal for each submerged macrophyte species at the water temperature ranging from 15°C to 25°C, while slight reduction in removal capability was observed at the water temperature less than 15°C and more than 25°C. The results showed that the removal capabilities were stable in the constructed biological system (CBS) with Ceratophyllum demersum. At low water temperature, the removal capability remained within a certain level in the CBSs with Potamogeton malaianus, Ceratophyllum demersum, Myriophyllum spicatum, Potamogeton oxyphyllus. Among the seven macrophyte species, the strongest affinity with zooplankton was observed for Ceratophyllum demersum. Accrording to the eological insight, cultivation of Ceratophyllum demersum is of prime importance during initial macrophyte-planting in eutrophic waters, because of its strong purification capability and affinity with zooplankton.