张晨玥　韩超南　胡美嘉　杨伟　陈天力

摘 要：為研究藻体消亡分解过程对水环境铁循环的影响，本研究以浓缩绿藻和太湖沉积物样品为试材进行室内柱培养实验。结果表明，室内柱培养环境中藻体在0～15 d内基本消亡至尽，且厌氧培养条件下上覆水的溶解氧（DO）含量、pH明显下降，主要因藻体消亡分解过程中不断耗氧、释放小分子有机酸所引起;培养后期（10～20 d），“空白-厌氧”组上覆水总铁（T-Fe）、可过滤铁（TD-Fe）和亚铁（Fe2+）含量相比其他组较高，原因是厌氧或缺氧环境下沉积物铁氧化物/氢氧化物还原为溶解态Fe2+释放入水体;然而，培养后期“加藻-好氧”和“加藻-厌氧”组Fe2+、T-Fe含量却波动下降，这可能由藻体分解释放的硫化物（S2-）与上覆水Fe2+反应生成硫化铁沉淀所致。研究表明，藻体分解过程通过改变上覆水pH、DO环境，释放S2-而影响铁氧化物的氧化还原作用、硫化固定作用，从而驱动Fe元素在上覆水与沉积物间的迁移转化。

关键词：藻体消亡;上覆水;溶解氧;铁形态

中图分类号：X143    文献标识码：A   文章编号：1006-8023（2021）02-0074-05

Dynamic Changes of Iron Species Concentrations in Water During

Algal Decomposition Process

ZHANG Chenyue， HAN Chaonan*， HU Meijia， YANG Wei， CHEN Tianli

（School of Civil Engineering， Nanjing Forestry University， Nanjing 210037， China）

Abstract：This study aimed to unravel the impact of algae extinction and decomposition on iron cycle in water environment. Sediments sampled from Taihu Lake and concentrated green algae were used as experimental materials for indoor column culture. The results showed that all the algae in the indoor column system died completely within 15 days. The dying algae gradually consumed oxygen and can even release small molecular organic acids， which caused DO contents and pH values in overlying water of the anaerobic culture environment decreased significantly. In the later stage of column culture （in the 10～20 days）， the concentrations of total iron （T-Fe）， filterable iron （TD-Fe） and ferrous iron （Fe2+） in overlying water of the "blank anaerobic" group were obviously higher than that in the other groups. This phenomenon was mainly related to the reduction of iron oxides or hydroxides in sediments and the release of dissolved Fe2+ for overlying water under anaerobic or anoxic conditions. However， the concentrations of Fe2+ and T-Fe in overlying water of the "algal aerobic" and "algal anaerobic" groups presented decline characteristics in the later stage. These were probably resulted from the precipitation formations of iron sulfide by Fe2+ and sulfide （S2-） which was released from algae decomposition. The findings of this study indicated that algae decomposition influenced iron hydroxide reduction， iron sulfide precipitation by reducing pH and DO values and releasing S2-， thus driving the migration and transformation of iron between overlying water and sediment.

Keywords：Algal decomposition; overlying water; dissolved oxygen; iron species

收稿日期：2020-11-13

基金项目：江苏省自然科学基金青年项目（BK20190763）;南京林业大学大学生实践创新计划项目（201910298044Z）;南京林业大学水杉师资人才科研启动项目（163050123）

通信作者：韩超南，博士，讲师。研究方向为水环境地球化学。E-mail： hcn_125@163.com

引文格式：张晨玥，韩超南，胡美嘉，等. 藻体消亡过程中水体铁形态含量的动态变化[J]. 森林工程，2021，37（2）：74-78.

ZHANG C Y， HAN C N， HU M J， et al. Dynamic changes of iron species concentrations in water during algal decomposition process[J]. Forest Engineering，2021，37（2）：74-78.

0 引言

湖泊水华现象暴发后，伴随大量藻体死亡分解过程，湖泊水体有时会出现发黑发臭的 “湖泛”现象，严重威胁着湖泊水质和水生态安全[1-3]。……