不同磷水平下铜绿微囊藻对砷酸盐的吸收和净化

通过室内培养实验,研究了富磷(+P)和缺磷(–P)环境下,铜绿微囊藻对砷酸盐(As(Ⅴ))的累积和净化动力学特征,探讨了净化过程中培养介质砷形态的变化.结果表明:缺磷环境下虽然可显著提升铜绿微囊藻对砷酸盐的吸收,但该环境下的高砷藻体又具较高的砷释放风险.+P和–P环境下,藻体中分别有41.5%和46.3%的胞内砷可在快速清除阶段(2h)被迅速排出.+P环境下经10μmol/L As(Ⅴ)暴露后的含砷藻体,经13d净化培养后,+P培养介质中藻体以砷酸盐释放为主,-P培养介质中则存在砷的还原和甲基化现象,这表明不同磷水平下藻体对砷的净化机理可能存在明显差异.

Uptake and depuration kinetics of arsenatein Microcystis aeruginosaunder different phosphate regimes

The uptake and depuration kinetics of arsenate inMicrocystis aeruginosa (M. aeruginosa) were investigatedunder phosphate-enriched (+P) and depleted (–P) culture conditions. Similarly, M. aeruginosa, pre-exposed to 10μmol/L arsenate for 24 hours under +P conditions, were used to examine arsenic efflux and species changes in culture media during 13 days depurations under +P and–P conditions. Results showed that P-depletion was found to significantly improve the accumulation of arsenate in Microcystis aeruginosa, in which the algae with high accumulated amounts of arsenic had high risks due to arsenic rapid efflux. Additionally, ca. 41.5% and 46.3%intracellular arseniccould be rapidly excreted in rapidclearance phase (2h) under +P and –P conditions, respectively. During the depuration period, arsenate efflux was the crucial process from algae cells in +P media, but arsenate reduction and methylation were observed in –Pmedia. This indicates significant differences inM. aeruginosa depuration mechanism under different phosphorus conditions.