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| Study on the Reduction Effect of Typical Meadow and Canopytype Submerged Plants on Endogenous Pollutants |
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| DOI：10.16768/j.issn.1004-874X.2023.05.009 |
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| Abstract: |
| 【Objective】This study is to explore the reduction effect of different growth patterns of submerged plants in controlling endogenous pollutants. 【Method】A selection of typical meadow and canopy-type submerged plants, Sagittaria pygmaea Miq and Hydrilla verticillate, experimental simulation system using sediment from a heavily polluted water body and two types of submerged plants respectively. The study analysed the growth and expansion of S. pygmaea Miq and Hydrilla verticillate in the contaminated sediment, and investigated the changes in the concentrations of major pollutants in the sediment and overlying water of each system, as well as the characteristics of the microbial community structure in the surface sediment. 【Result】Both submerged plants tolerated and expanded in the contaminated sediment in this study, with both the stem and root biomass of S. pygmaea Miq expanding 10-fold, but mainly within the upper and lower 10 cm of the sediment interface, The stem and leaf biomass of H. verticillate also expanded 10-fold throughout the overlying water space, but the root biomass remained unchanged. The removal of acid volatile sulphide (AVS), ferrous iron and ammonia nitrogen from the surface sediment (0-10 cm) of the S. pygmaea Miq system reached 80.57%, 67.43% and 72.48% , respectively, while the removal rates of ferrous iron and ammonia nitrogen in the H. verticillate system were only 24.75% and 61.41%, the removal rate of acid volatile sulphide (AVS) increased by 13.6%. The mean chlorophyll a concentrations in the overlying water were 9.61 μg/L and 9.39 μg/L for the H. pygmaea Miq and H. verticillate systems, respectively. The results of 16S rRNA high-throughput sequencing showed that there were significant differences in the composition of genera in the microbial communities of the surface sediments of the two systems, with the dominant genera in the S. pygmaea Miq system being Sulfurifustis and Nitrospira, while the dominant genera in the H. verticillate system being Cyanobium_PCC-6307,Spirochaeta_2, Sphingomonas and Geothermobacter with much higher relative abundance. 【Conclusion】The S. pygmaea Miq were more effective in removing the reducing pollutants AVS, ferrous iron and ammonia nitrogen from the surface sediment, while. verticillate was more effective in controlling the growth of algae in the overlying water. The well-developed root system of S. pygmaea Miq promotes the development of microbial taxa for sulphur and ammonia nitrogen metabolism. |
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