Abstract: Through monitoring the density of aquatic plants, surface coverage rate of the floating bed, water quality, characteristics of phytoplankton communities and growth of hydrobionts in a shrimp-rearing pond during September 2009 to February 2010, effects of combinations of submerged macrophytes with ecological floating beds on in-situ purification and regulation of water quality were studied. It was found that the combination of planting 4.0 kg Vallisneria natans and 3.0 kg Hydrilla verticillata with the floating bed of 312 hills of Iris hexagonus in Enclosure V was the most effective in controlling aquacultural pollution, with TN,TP and COD_Mn decreased in concentration from 3.41, 0.32 and 14.34 to 0.79, 0.02 and 11.96 mg·L^-1, respectively. In this enclosure, the Margalef index of phytoplankton was 4.00, the Shannon-Wiener diversity index 3.32, and the evenness index 0.76, which demonstrate that its water environment is quite stable and its water quality quite good. A new aquacultural water purification model of combining submerged macrophyte with ecological floating beds has been developed in this study.

Key words: submerged macrophyte, ecological floating bed, Land-based enclosure, aquacultural pollution, water purification