全球淡水湖中的蓝藻有害藻华(cyanoHAB)通常与其他压力源结合在一起。制药污染,尤其是水体中的抗生素,对水生生态系统构成潜在危害。然而,抗生素如何影响氰化HABs的风险尚不清楚.这里,我们研究了诺氟沙星(NOR)的作用,全球使用最广泛的抗生素之一,形成水华的蓝细菌(铜绿微囊藻)和普通的绿藻(Scenedesmusquadricauda),在单一和共培养条件下。在单一培养中评估了对NOR的分类单元特异性反应。此外,测定了暴露于NOR共培养时蓝藻与绿藻的生长速率和比例变化。在微囊藻的单种培养中,暴露于低浓度的NOR导致生物量减少,叶绿素a和可溶性蛋白质含量,而超氧阴离子含量和超氧化物歧化酶活性增加。然而,高浓度下的NOR仅对Scenedesmus产生轻微影响。在微囊藻和栅藻的共培养试验中,5μg·L-1NOR处理可使微囊藻与共培养栅藻的比例提高47.2%。同时,尽管在单一培养的NOR处理下,栅藻生长增加了4.2%,当与微囊藻共培养有和没有NOR时,它被抑制了63.4%和38.2%,分别。我们的结果表明,抗生素污染具有通过干扰蓝细菌和绿藻之间的种间相互作用来增强cyanoHAB的危害性的潜在风险。这些结果加强了科学家和管理人员在塑造水生生态系统中多种物种之间相互作用结果时考虑外源性物质的影响的必要性。
Cyanobacterial harmful algal blooms (cyanoHABs) in freshwater lakes across the globe are often combined with other stressors. Pharmaceutical pollution, especially antibiotics in water bodies, poses a potential hazard in aquatic ecosystems. However, how antibiotics influence the risk of cyanoHABs remains unclear. Here, we investigated the effects of norfloxacin (NOR), one of the most widely used antibiotics globally, to a bloom-forming cyanobacterium (Microcystis aeruginosa) and a common green alga (Scenedesmus quadricauda), under both mono- and coculture conditions. Taxon-specific responses to NOR were evaluated in monoculture. In addition, the growth rate and change in ratio of cyanobacteria to green algae when cocultured with exposure to NOR were determined. In monocultures of Microcystis, exposure to low concentrations of NOR resulted in decreases in biomass, chlorophyll a and soluble protein content, while superoxide anion content and superoxide dismutase activity increased. However, NOR at high concentration only slightly affected Scenedesmus. During the co-culture trials of Microcystis and Scenedesmus, the 5 μg · L-1 NOR treatment increased the ratio of Microcystis to co-cultured Scenedesmus by 47.2%. Meanwhile, although Scenedesmus growth was enhanced by 4.2% under NOR treatment in monoculture, it was conversely inhibited by 63.4% and 38.2% when co-cultured with Microcystis with and without NOR, respectively. Our results indicate that antibiotic pollution has a potential risk to enhance the perniciousness of cyanoHABs by disturbing interspecific interaction between cyanobacteria and green algae. These results reinforce the need for scientists and managers to consider the influence of xenobiotics in shaping the outcome of interactions among multiple species in aquatic ecosystems.