Li Shun-Xing, Zheng Feng-Ying, Deng Nan-Sheng, Hong Hua-Sheng, Zhu Guo-Hui
Zhangzhou Teachers College, Zhangzhou 363000, China.
Huan Jing Ke Xue. 2005 Jul;26(4):45-50.
Seven marine phytoplankton, including five green algae (Tetraselmis levis, Chlorella autotrophica, Dunaliella salina, Nannochloropsis sp. and Tetraselmis subcordiformis), one diatom (Phaeodactylum tricornutum), one red alga (Porphyridium purpureum), and three usual transitional metals (Fe(III), Cu(II), Mn(II)) were used to make up marine phytoplankton-light or transitional metals-light or marine phytoplankton-transitional metals-light system. In such system, Se(VI) could be transformed into Se(IV) by photoreduction. The species transformation of selenium could be photo-induced by redox reaction of transitional metals. The photochemical activity of marine phytoplankton was confirmed for the first time, because marine phytoplankton could adsorb and concentrated of selenium, transitional metals and organic substances (including the exudation of algae, as reducing agent) which redox potentials were changed. The ratios of Se(VI) to Se(IV) were dominated by the species, the concentration of marine phytoplankton and transitional metals, and it could be enhanced through increasing the concentration of marine algae or the combined effect from marine algae and transitional metals. After photoreduction by ternary system, the ratio of Se(VI) to Se(IV) ranges from 1.17 to 2.85, which is close to the actual value in euphotic layer of seawater. The photochemical process that is induced by marine algae and transitional metals dominative the leading effects on the distribution of oxidation states of selenium.
七种海洋浮游植物，包括五种绿藻（纤细角毛藻、自养小球藻、盐生杜氏藻、微拟球藻和亚心形扁藻）、一种硅藻（三角褐指藻）、一种红藻（紫球藻），以及三种常见过渡金属（Fe(III)、Cu(II)、Mn(II)）被用于构建海洋浮游植物-光或过渡金属-光或海洋浮游植物-过渡金属-光体系。在该体系中，Se(VI)可通过光还原转化为Se(IV)。硒的物种转化可由过渡金属的氧化还原反应光诱导。首次证实了海洋浮游植物的光化学活性，因为海洋浮游植物能够吸附并浓缩硒、过渡金属和有机物质（包括藻类分泌物，作为还原剂），其氧化还原电位发生了变化。Se(VI)与Se(IV)的比例受物种、海洋浮游植物和过渡金属浓度的影响，并且可以通过增加海藻浓度或海藻与过渡金属的联合作用来提高。三元体系光还原后，Se(VI)与Se(IV)的比例在1.17至2.85之间，接近海水真光层中的实际值。由海藻和过渡金属诱导的光化学过程对硒氧化态的分布起主导作用。
