Dynamic distribution characteristics and its relationship with water environment factors of dissolved organic matter in Lake Chaohu,China
To illuminate the properties and characteristics of dissolved organic matter(DOM)in Lake Chaohu,a typical eutrophic lake,a year-round survey was conducted from March 2021 to January 2022.Three-dimensional fluorescence spectroscopy combined with parallel factor analysis(PARAFAC)was conducted to investigate the composition,spatiotemporal distribution characteristics,sources of DOM,and its relationship with water environ-ment factors.The results showed that the DOM in Lake Chaohu water contains of three fluorescent components:protein-like C1(Ex/Em=280/320),humic-like C2(Ex/Em=285/380)and C3(Ex/Em=270(355)/450).The fluorescence intensities of these components showed distinct spatiotemporal distribution characteristics,with C1,C2,and C3 flu-orescence intensities being significantly higher in the summer than in other seasons and markedly higher in the West Lake area compared to the Central and East Lake areas.The results of Pearson correlation analysis and redundancy analysis(RDA)indicated that chlorophyll(Chl-a),total nitrgen(TN),total phosphorus(TP),and temperature(T)are influencing factors of the spatiotemporal changes of C1,C2,and C3 components.The fluorescence indices of DOM,including the fluorescence index(FI),biological source index(BIX),and humification index(HIX),ranged from 1.96 to 2.83,0.83 to 1.18,and 1.35 to 5.36,respectively,indicating that while autochthonous sources dominate the DOM in the lake water,terrestrial and endogenous sources also contribute significantly during the summer.The research findings demonstrated that by tracking the composition,sources,spatiotemporal distribution patterns,and response mechanisms of DOM in the water of Lake Chaohu,strong scientific and technological could be provided support for the control and integrated management of pollutants in eutrophic lakes.
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