论文部分内容阅读
利用三维荧光光谱分析手段,结合吸收光谱测定,分析了2007年10月中国珠江口及北部湾水体中4个典型有色溶解有机物(CDOM)样在太阳光辐照下的光降解特性.结果表明,珠江口及广西沿海CDOM样受陆源输入影响较大,而北部湾中部的HX样具有典型海洋CDOM特征,80m水深的HN样则受到北部湾环流的主要影响.这些CDOM样品中均观测到类腐殖质荧光峰A、C、M以及类色氨酸荧光峰R、T,它们的荧光峰强度及吸收系数a(280)在秋季短期日光辐照下发生了较明显的光化学降解,受陆源输入影响较大的珠江口及广西沿海样品的光降解程度高于北部湾的远岸样品,反映出它们含有更多的发色团.光降解未引起CDOM荧光峰位置的显著变化,类腐殖质荧光峰M和A、类蛋白质荧光峰R和T的强度变化趋势一致,表明这两对峰具有相似的性质.A峰区存在的双峰现象表明其为多个荧光组分的叠加.CDOM吸收光谱的光谱斜率S(270～350)随光辐射而逐渐增加,可用于指示光降解引起的CDOM分子量的减小趋势.研究表明,光降解在南海生源要素的生物地球化学循环中起重要作用.
The photodegradation characteristics of four typical colored dissolved organic matter (CDOM) samples from the Pearl River Mouth and Beibu Bay waters in China in October 2007 under solar irradiation were analyzed by three-dimensional fluorescence spectroscopy and absorption spectroscopy. The results showed that, The CDOM samples in the Pearl River Estuary and the coastal areas of Guangxi Province are greatly affected by terrestrial input, while the HX samples in the central northern Gulf have typical marine CDOM features, while the HN samples at 80 m depth are mainly affected by the Beibu Gulf circulation. Fluorescent peaks A, C, M and tryptophan-like fluorescence peaks R, T, their fluorescence peak intensity and absorption coefficient a (280) under photoperiod of autumn short-term light irradiation were more obvious photochemical degradation, Photodegradation of the larger Pearl River Estuary and Guangxi coastal samples was higher than that of the northern Gulf, reflecting that they contained more chromophores. Photodegradation did not cause any significant change in the fluorescence peak position of CDOM. The fluorescence peak of humic type M and A, the fluorescence intensity of R and T showed the same trend, indicating that the two pairs of peaks have similar properties.The bimodal phenomenon existing in the peak area of A shows that it is the superposition of multiple fluorescence components.CDOM absorption spectrum Spectral slope S (270 ~ 350) is gradually increased with the light radiation, may be used to reduce the tendency of the molecular weight due to indicate CDOM photodegradation. Studies have shown that photodegradation play an important role in biogeochemical cycling of biogenic elements in the South China Sea.