结合镧改性膨润土（LMB）和沉水植物可缓解在存在杂食性底栖鱼类的情况下水质恶化。
Combining lanthanum-modified bentonite (LMB) and submerged macrophytes alleviates water quality deterioration in the presence of omni-benthivorous fish.
作者信息
Han Yanqing, Jeppesen Erik, Lürling Miquel, Zhang You, Ma Tingting, Li Wei, Chen Kunquan, Li Kuanyi
机构信息
State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, China; University of Chinese Academy of Sciences, Beijing, 100049, China.
Sino-Danish Centre for Education and Research, Beijing, 100049, China; Department of Bioscience, Aarhus University, Vejlsøvej 25, 8600, Silkeborg, Denmark; Limnology Laboratory, Department of Biological Sciences and Centre for Ecosystem Research and Implementation, Middle East Technical University, Ankara, 06800, Turkey; Institute of Marine Sciences, Middle East Technical University, Erdemli-Mersin, 33731, Turkey.
出版信息
J Environ Manage. 2022 Jul 15;314:115036. doi: 10.1016/j.jenvman.2022.115036. Epub 2022 Apr 11.
Bioturbation by omni-benthivorous fish often causes sediment resuspension and internal nutrient loading, which boosts phytoplankton growth and may lead to a shift of clear water lakes to a turbid state. Removal of large-sized omni-benthivorous individuals is a lake restoration measure that may revert lakes from a turbid to a clear water state, yet the rapid reproduction of small omni-benthivorous fish in tropical and subtropical shallow lakes may impede such lake recovery. In lake restoration, also a combination of lanthanum-modified bentonite (LMB) and planting submerged macrophytes has been used that may synergistically improve lake water quality. How the combined effect works in the presence of small omni-benthivorous fish has not been studied, which is needed given the high abundances of small omni-benthivorous fish in (sub)tropical lakes. We conducted a two-by-two factorial mesocosm experiment with and without the submerged macrophytes Vallisneria natans and with and without LMB, all in the presence of small crucian carp. At the end of the experiment, turbidity in the V. natans, LMB and combined LMB + V. natans treatments had decreased by 0.8%, 30.3% and 30.9%, respectively, compared with the controls. In addition, the nitrogen (N) and phosphorus (P) release from the sediment in the combined LMB + V. natans treatments had decreased substantially, by 97.4% and 94.3%, respectively, compared with the control. These N and P fluxes were also significantly lower in the combined LMB + V. natans treatments than in the sole LMB treatment (88.1% and 82.3%) or the V. natans treatment (93.2% and 90.3%). Cyanobacteria in the overlying water in the combined LMB + V. natans treatments significantly decreased by 84.1%, 63.5% and 37.0%, respectively, compared with the control and the sole LMB and V. natans treatments. Our results show that LMB and submerged macrophytes complement each other in effectively improving the water quality, even in the presence of small omni-benthivorous fish.
杂食性底栖鱼类引起的生物扰动常常导致沉积物再悬浮和内部营养物质负荷增加，这会促进浮游植物生长，并可能导致清水湖泊向浊水状态转变。去除大型杂食性底栖个体是一种湖泊恢复措施，有望使湖泊从浊水状态恢复到清水状态，然而热带和亚热带浅水湖泊中小型杂食性鱼类的快速繁殖可能会阻碍这种湖泊恢复。在湖泊恢复中，也采用了镧改性膨润土（LMB）和种植沉水植物相结合的方法，这可能会协同改善湖泊水质。在小型杂食性鱼类存在的情况下，这种联合效应是如何起作用的尚未得到研究，鉴于（亚）热带湖泊中小型杂食性鱼类数量众多，这一研究很有必要。我们进行了一项二乘二析因中宇宙实验，设置有和没有沉水植物苦草、有和没有LMB这几种情况，且实验全程都有小鲫鱼存在。在实验结束时，与对照组相比，苦草、LMB以及LMB + 苦草联合处理组的水体浊度分别下降了0.8%、30.3%和30.9%。此外，与对照组相比，LMB + 苦草联合处理组沉积物中的氮（N）和磷（P）释放量大幅下降，分别下降了97.4%和94.3%。这些N和P通量在LMB + 苦草联合处理组中也显著低于单独的LMB处理组（分别为88.1%和82.3%）或苦草处理组（分别为93.2%和90.3%）。与对照组以及单独的LMB和苦草处理组相比，LMB + 苦草联合处理组上覆水中的蓝藻分别显著减少了84.1%、63.5%和37.0%。我们的结果表明，即使在存在小型杂食性底栖鱼类的情况下，LMB和沉水植物在有效改善水质方面也能相互补充。
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