Photochemical degradation of chromophoric-dissolved organic matter exposed to simulated UV-B and natural solar radiation

被引：134

作者：

Zhang, Yunlin ^{[1
,2
]}

Liu, Mingliang ^{[1
]}

Qin, Boqiang ^{[1
]}

Feng, Sheng ^{[3
]}

机构：

[1] Chinese Acad Sci, Taihu Lake Lab Ecosystem Res Stn, State Key Lab Lake Sci & Environm, Nanjing Inst Geog & Limnol, Nanjing 210008, Peoples R China

[2] Netherlands Inst Ecol NIOO KNAW, Ctr Limnol, NL-3631 AC Nieuwersluis, Maarssen, Netherlands

[3] Chinese Acad Sci, Inst Urban Environm, Xiamen 361003, Peoples R China

来源：

HYDROBIOLOGIA | 2009年 / 627卷 / 01期

基金：

中国国家自然科学基金;

关键词：

Absorption coefficient; Fluorescence; Photobleaching; Spectral slope; ULTRAVIOLET-RADIATION; OPTICAL-PROPERTIES; ESTUARINE SYSTEM; MOLECULAR-WEIGHT; COASTAL; ABSORPTION; CARBON; CDOM; PHOTOREACTIONS; ATTENUATION;

D O I：

10.1007/s10750-009-9722-z

中图分类号：

Q17 [水生生物学];

学科分类号：

071004 ;

摘要：

Photochemical degradation of chromophoric-dissolved organic matter (CDOM) by UV-B radiation decreases CDOM absorption in the UV region and fluorescence intensity, and alters CDOM composition. CDOM absorption, fluorescence, and the spectral slope indicating the CDOM composition were studied using 0.22-mu m-filtered samples of Meiliang Bay water from Lake Taihu that were exposed to short-term (0-12 h) simulated UV-B radiation and long-term (0-12 days) natural solar radiation in summer. CDOM absorption coefficient and fluorescence decreased with increasing exposure time, which relates to the amounts of absorbed light energy. The decreases of CDOM absorption and normalized fluorescence corresponded to first order kinetics reactions. Different decreases of CDOM absorption and fluorescence at different wavelengths suggested that the composition of CDOM changed when it absorbed ultraviolet radiation. Photochemical degradation increased the spectral slope during 275-295 nm region (S275-295) but decreased the spectral slope during 275-295 nm region (S350-400). The slope ratio S-R (S275-295: S350-400) increased in the photochemical process, which could be used as an indicator of photobleaching and composition change of CDOM. Our results show that photochemical degradation is important in the cycling of CDOM, which indicated change in the composition of CDOM.

引用

页码：159 / 168

页数：10

共 45 条

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