| 基于紫外-可见光吸收光谱和三维荧光光谱的腐殖酸光降解组分特征分析 |
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| 引用本文： | 赵紫凡,孙欢,苏雅玲.基于紫外-可见光吸收光谱和三维荧光光谱的腐殖酸光降解组分特征分析[J].湖泊科学,2019,31(4):1088-1098. |
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| 作者姓名： | 赵紫凡 孙欢 苏雅玲 |
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| 作者单位： | 中国科学院南京地理与湖泊研究所湖泊与环境国家重点实验室,南京210008;中国科学院大学,北京100049;中国科学院南京地理与湖泊研究所湖泊与环境国家重点实验室,南京,210008 |
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| 基金项目： | 国家自然科学基金项目（31670461）和国家水体污染控制与治理科技重大专项（2017ZX07203-005）联合资助. |
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| 摘 要： | 湖泊生态系统作为自然界重要的碳库，光照强度的变化对于湖泊的碳循环过程可能产生重要的影响.以云南老君山高山湖泊天才湖周边土壤中的腐殖酸作为外源溶解性有机物（DOM）的代表物，通过腐殖酸模拟光降解实验，考察光照强度对外源DOM光降解过程的影响.研究结果表明：腐殖酸光吸收系数a440、465 nm和665 nm波长处吸光度比值E4/E6的下降幅度均为：对照组 < 20 W光照组 < 40 W光照组，a440、E4/E6和光谱斜率SR显著相关，表明紫外辐射使得腐殖酸溶液浓度降低、相对分子量下降，且光照强度越强，腐殖酸的光降解程度越大.通过EEM-PARAFAC模型识别出光降解过程中腐殖酸溶液中含有5种荧光组分：UV类腐殖质（C1）、UVA类腐殖质（C2）、类色氨酸（C3）、UVC类腐殖质（C4）和类络氨酸（C5）.40 W光照组中4种荧光组分的降解程度与降解速率均大于20 W光照组，降解程度均为：C4 > C3 > C2 > C1，降解速率为C2 > C4 > C3 > C1，说明不同的荧光组分对光照强度的响应不同.该研究有助于阐明外源DOM的光降解途径与归趋.
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| 关 键 词： | 腐殖酸 光降解 吸收光谱 荧光光谱 天才湖 |
| 收稿时间： | 2018/9/11 0:00:00 |
| 修稿时间： | 2019/1/16 0:00:00 |
Photodegradation response of humic acid using UV-Visible absorption and Excitation-Emission Matrix Spectra |
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| ZHAO Zifan,SUN Huan and SU Yaling.Photodegradation response of humic acid using UV-Visible absorption and Excitation-Emission Matrix Spectra[J].Journal of Lake Science,2019,31(4):1088-1098. |
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| Authors: | ZHAO Zifan SUN Huan and SU Yaling |
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| Institution: | State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, P. R. China;University of Chinese Academy of Sciences, Beijing 100049, P. R. China,State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, P. R. China;University of Chinese Academy of Sciences, Beijing 100049, P. R. China and State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, P. R. China |
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| Abstract: | UV irradiation intensity changes have great influence on carbon cycle in lake, which is one of the most important carbon pools in nature. To understand the effects of UV irradiation on allochthonous dissolved organic matter(DOM)in lakes, simulated photodegradation experiments were conducted. We extracted humic acid from soil surrounding an alpine Lake Tiancai as allochthonous DOM. During the photo-irradiation process, the order of decreasing level of a440 and E4/E6 was 40 W group, followed by 20 W group and control group. Moreover, SR, a440 and E4/E6 were significantly correlated, suggesting that the concentration and relative molecular weight of humic acid decreased with increasing UV irradiation intensity. Five fluorescent components were identified through using EEM-PARAFAC models, included UV humic-like component (C1), UVA humic-like component (C2), tryptophan-like component (C3), UVC humic-like component (C4), tyrosine-like component (C5). The photodegradation rate and degree of four fluorescent components in 40 W group were greater than 20 W group, the order of photodegradation rate was C4 > C3 > C2 > C1 and the order of photodegradation degree was C2 > C4 > C3 > C1, indicating that fluorescent components response diversely to different UV irradiation intensities. |
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| Keywords: | Humic acid photodegradation absorption spectra Excitation-Emission Matrix Spectra Lake Tiancai |
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