State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, No.73 East Beijing Road, 210008, Nanjing, Jiangsu Province, People's Republic of China.
University of Chinese Academy of Sciences, Beijing, 100049, China.
Environ Sci Pollut Res Int. 2021 May;28(17):21779-21788. doi: 10.1007/s11356-020-12045-8. Epub 2021 Jan 7.
Lanthanum-modified bentonite (LMB) is widely used for eutrophication control and has demonstrated good efficiency in some eutrophic lakes. However, the efficiency of LMB on eutrophication control in some eutrophic lakes, where the structure of food webs is mainly dominated by omni-benthivorous fish, remains ambiguous. Omni-benthivorous fish usually disturbs sediment and promotes the release of internal nutrients, the effect of which on the efficacy of LMB remains to be studied. Thus, a 30-day mesocosm experiment was conducted to determine whether omni-benthivorous fish disturbance and LMB would cause antagonistic responses. LMB significantly reduced dissolved P concentration in overlying water, converting mobile P to bound P in the surface layer of sediment in the absence of crucian carp (Carassius carassius). However, there were significantly negative interaction effects between LMB and crucian carp. Although LMB still effectively reduced the total dissolved phosphorus (TDP) and soluble reactive phosphorus (SRP) concentrations of overlying water in the presence of crucian carp, it had limited efficacy on inhibiting the increased concentrations of suspended solids, particulate nutrients, and chlorophyll a (Chl a) due to crucian carp disturbance. Furthermore, the crucian carp disturbance also increased the risk of mobile P releasing from surface sediment, whether with or without LMB application. The results indicated that the efficacy of LMB was insufficient to offset the negative effect of omni-benthivorous fish disturbance on eutrophication control. Hence, the omni-benthivorous fish also need to be considered for eutrophication control in shallow eutrophic lakes. Some measures need to be taken to control the biomass of omni-benthivorous fish.
镧改性膨润土（LMB）被广泛用于富营养化控制，并且在一些富营养化湖泊中已证明具有良好的效果。然而，在一些富营养化湖泊中，LMB 对富营养化控制的效果仍不明确，这些湖泊中食物网的结构主要由杂食性鱼类主导。杂食性鱼类通常会干扰底泥并促进内部营养物质的释放，其对 LMB 效果的影响仍有待研究。因此，进行了为期 30 天的中宇宙实验，以确定杂食性鱼类的干扰和 LMB 是否会产生拮抗反应。在没有鲫鱼（Carassius carassius）的情况下，LMB 显著降低了上覆水中的溶解磷浓度，将可移动的磷转化为沉积物表面层中的结合磷。然而，LMB 和鲫鱼之间存在显著的负相互作用效应。尽管 LMB 仍然有效地降低了鲫鱼存在时上覆水中的总溶解磷（TDP）和可溶反应性磷（SRP）浓度，但由于鲫鱼的干扰，它对抑制悬浮固体、颗粒养分和叶绿素 a（Chl a）浓度的增加效果有限。此外，鲫鱼的干扰也增加了表层沉积物中可移动磷释放的风险，无论是否应用 LMB。结果表明，LMB 的效果不足以抵消杂食性鱼类干扰对富营养化控制的负面影响。因此，在浅水富营养化湖泊中进行富营养化控制时也需要考虑杂食性鱼类。需要采取一些措施来控制杂食性鱼类的生物量。
