Selenite(IV) and selenate(VI) are the major species of Se in the seleniferous aquatic ecosystem. The redistribution of Se in the water/sediment microcosm by bioturbation remains largely unknown. In this study, the redistribution of Se in the water/sediment microcosm by the benthic oligochaete Limnodrilus hoffmeisteri was assessed. The worms were exposed to 2–40 μg/g dry weight of Se(IV) or Se(VI) in the sediment (diet) for 2 months. The changes in the Se levels in different compartments of the microcosm (sediment, overlying water, and worms) were quantified after 2 weeks and 2 months. The subcellular distribution of Se in the worms were also evaluated. Finally, the volatilization of Se from the two Se sources was estimated. The results showed that Se concentration in the overlying water and Se bioaccumulation in the worms were increased with Se levels in the sediments. Approximately 1.6–9.8% of Se was volatilized in the absence of the worms and was intensified in the presence of the worms (2.1–25.7%). The subcellular distribution witnessed high levels of Se in the cell debris (>60%). Se(IV) and Se(VI) differ in their bioaccumulation, redistribution and the effects on the growth of the worms. Our results suggest that the bioturbation by benthos play an essential role in the redistribution of Se in the water/sediment microcosm.

亚硒酸盐（IV）和硒酸盐（VI）是硒状水生生态系统中硒的主要物种。通过生物扰动在水/沉积物微观世界中Se的重新分布仍然是未知的。在这项研究中，底栖低聚鱼类Limnodrilus hoffmeisteri在水/沉积物缩影中Se的重新分布被评估。将蠕虫暴露于沉积物（饮食）中干重为2–40μg/ g的Se（IV）或Se（VI）中2个月。在2周和2个月后，对微观世界不同区域（沉积物，上覆水和蠕虫）中Se含量的变化进行了定量。还评估了蠕虫中硒的亚细胞分布。最后，估计了来自两种硒源的硒的挥发。结果表明，随着沉积物中硒含量的增加，上覆水中硒的浓度和蠕虫中硒的生物积累量均增加。在没有蠕虫的情况下，约有1.6–9.8％的Se挥发，而在蠕虫的存在下，硒的含量则升高（2.1–25.7％）。亚细胞分布见证了细胞碎片中硒含量高（> 60％）。Se（IV）和Se（VI）的生物蓄积能力不同，重新分布及其对蠕虫生长的影响。我们的结果表明，底栖生物的生物扰动在水/沉积物微观世界中硒的重新分布中起着至关重要的作用。