| Aquatic ecosystem rehabilitation and restablishment have received more and more attention nationally in water environment field of China. Prevenient research shows the revegetation of submerged macrophytes is the base for water ecosystem rehabilitation. Photoinhibition is the major stress to submerged macrophytes because of its complete submarine feature. At present, no effective technical measure to settle this problem is found. In this condition, as a new plant technique for overcoming impacts on submerged aquatic plants of illumination distribution underwater, the gradual-submerging bed technique(GSB) is first presented in this article, which considers adjust as plants' living zone to settle this problem.The main work in the thesis is summarized as follows:1 The selective principles of submerged aquatic species for GSB technique were presented in this article. According to these principles, the author selected Hydrilia verticillata and Elodea nuttll as suitable pioneer submerged macrophytes for Suzhou 863 Project.2 In this article, intercomparsion of several different vegetate materials was discussed from contaminations release, growth potential, biotic province and improvement effects of water environment. The result shows that coconut fiber is a suitable vegetate material of Hydrilia verticillata and Elodea nuttll for GSB technique.3, Interrelation of light compensation depth, hanging depth of GSB and submerged macrophytes revegetation were discussed in this article. Submerged macrophytes can only revegetate in light compensation zone as a conclusion was presented.4 GSB technique was tested in the Miaojiahe River in order to study its feasibility and practice effects based on experiment and analysis results.The result shows that GSB technique has primary feasibility to overcome low light compensation depth, improve water body's surrounding environments, and promote of submerged macrophytes revegetation. |
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