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Influence of Sediment Nitrogen and Phosphorus on Growth of Nymphoides peltatum and Water Quality |
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KeyWord:eutrophication; Nymphoides peltatum; nitrogen and phosphorus; biomass; morphological responses |
Author Name | Affiliation | YANG Xin | State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China | ZHANG Qi-chao | State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China | SUN Shu-yun | State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China | SHI Xian | State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China | CHEN Kai-ning | State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China |
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Abstract: |
Sediments can release nutrients into the water and thus impact the growth of floating plants. An experiment was carried out to investigate the influence of sediment nitrogen and phosphorus on the growth of floating-leafy macrophyte Nymphodies peltatum and water quality. Sediments were collected between Dongshan and Xishan of East Taihu Lake. Five levels of total nitrogen(TN) and total phosphorus(TP) were obtained by adding KNO3, K2HPO4 and sand. They were (A):TN 627.47 mg·kg-1 and TP 237.38 mg·kg-1; (B):TN 1 094.23 mg·kg-1 and TP 317.72 mg·kg-1;(C):TN:1 520.12 mg·kg-1 and TP:544.27 mg·kg-1(in situ sediment);(D):TN 2 047.83 mg·kg-1 and TP 738.37 mg·kg-1; and(E):TN 2 537.20 mg·kg-1 and TP 942.37 mg·kg-1. The results showed that aboveground biomass, leaf number and leaf area of N. peltatum were significantly higher in the sediment C than in other four sediments(P<0.05). However, the growth of N. peltatum was inhibited in the sediment E. Water quality of sediment E was worst with dissolved oxygen(DO), chlorophyll a(Chl. a) content and turbidity significantly different from the others(P<0.05). Removal rates of TN and TP from water by N. peltatum were greater at the early growth stage, less at later stage, and even negative at final stage. Our results indicate that sediments with lower or higher TN and TP would be unfavorable for the growth of N. peltatum. Best growth of N. peltatum in the situ sediments from Taihu Lake is the reason that caused its expansion in East Taihu Lake. Therefore, attention should be paid to the resultant ecological problems. |
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