Photodegradation of intracellular DOM from Microcystis aeruginosa and its effect on the binding of pyrene
YANG Cheng-hu1, LIU Yang-zhi1, ZHU Ya-xian2, ZHANG Yong1,3
1. State Key Laboratory of Marine Environmental Science of China, Xiamen University, College of the Environment and Ecology, Xiamen University, Xiamen 361102, China;
2. College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
UV-visible spectroscopy and fluorescence spectroscopy were applied to study the photodegradation of intracellular dissolved organic matter (IDOM) from Microcystis aeruginosa (M. aeruginosa-IDOM)upon ultraviolet A (UV-A) irradiation under oxic and anoxic conditions. Furthermore, the binding affinity of pyrene with the M. aeruginosa- IDOM was investigated by fluorescence quenching method throughout the process of photodegradation. After 6 d irradiation, the reduction of dissolved organic carbon (DOC) and absorption coefficient a355 under oxic condition were larger than those under anoxic condition. The variations of absorbance ratio E2/E3 (250nm/365nm) for oxic and anoxic photodegradation were similar. However, the variations of specific ultraviolet absorbance at 254nm (SUVA254) were strikingly different. Fluorescence excitation-emission matrix spectroscopy (EEMs) combined with parallel factor (PARAFAC) analysis showed that the changes in protein-like component, long-wavelength-excited humic-like component and short-wavelength-excited humic-like component were different for the two cases. The half-lives of photodegradation kinetics parameters of the M. aeruginosa-IDOM under oxic condition, which could be described using the first-order kinetics equation, were shorter than those parameters of anoxic condition. In addition, the affinity of the M. aeruginosa-IDOM for binding pyrene decreased under oxic condition, while first decreasing and later increasing trend was observed for pyrene binding affinity under anoxic condition.
杨承虎, 刘洋之, 朱亚先, 张勇. 铜绿微囊藻胞内DOM光降解及其对芘结合能力的影响[J]. 中国环境科学, 2016, 36(6): 1850-1858.
YANG Cheng-hu, LIU Yang-zhi, ZHU Ya-xian, ZHANG Yong. Photodegradation of intracellular DOM from Microcystis aeruginosa and its effect on the binding of pyrene. CHINA ENVIRONMENTAL SCIENCECE, 2016, 36(6): 1850-1858.
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