Abstract：
Aquatic ecosystems and their communities are exposed to numerous stressors of various natures (chemical and physical), whose impacts are often poorly documented. In urban areas, the use of biocides such as dodecyldimethylbenzylammonium chloride (DDBAC) and their subsequent release in wastewater result in their transfer to urban aquatic ecosystems. DDBAC is known to be toxic to most aquatic organisms. Artificial light at night (ALAN) is another stressor that is increasing globally, especially in urban areas. ALAN may have a negative impact on photosynthetic cycles of periphytic biofilms, which in turn may result in changes in their metabolic functioning. Moreover, studies suggest that exposure to artificial light could increase the biocidal effect of DDBAC on biofilms. The present study investigates the individual and combined effects of DDBAC and/or ALAN on the functioning and structure of photosynthetic biofilms. We exposed biofilms in artificial channels to a nominal concentration of 30 mg.L-1 of DDBAC and/or ALAN for 10 days. ALAN modified DDBAC exposure, decreasing concentrations in the water but not accumulation in biofilms. DDBAC had negative impacts on biofilm functioning and structure. Photosynthetic activity was inhibited by > 90% after 2 days of exposure, compared to the controls, and did not recover over the duration of the experiment. Biofilm composition was also impacted, with a marked decrease in green algae and the disappearance of microfauna under DDBAC exposure. The integrity of algal cells was compromised where DDBAC exposure altered the chloroplasts and chlorophyll content. Impacts on autotrophs were also observed through a shift in lipid profiles, in particular a strong decrease in glycolipid content was noted. We found no significant interactive effect of ALAN and DDBAC on the studied endpoints.
摘要：
水生生态系统及其群落暴露于各种性质（化学和物理）的众多压力源，其影响通常记录不佳。在城市地区,诸如十二烷基二甲基苄基氯化铵（DDBAC）之类的杀生物剂的使用以及它们随后在废水中的释放导致它们转移到城市水生生态系统。已知DDBAC对大多数水生生物是有毒的。夜间人造光（ALAN）是另一个在全球范围内增加的压力源，尤其是在城市地区。ALAN可能对外周生物膜的光合周期产生负面影响，这反过来又可能导致其代谢功能的变化。此外，研究表明，暴露于人造光可以增加DDBAC对生物膜的杀生物作用。本研究调查了DDBAC和/或ALAN对光合生物膜的功能和结构的单独和组合影响。我们将人工通道中的生物膜暴露于标称浓度为30mg。DDBAC和/或ALAN的L-1持续10天。ALAN修改的DDBAC曝光，降低水中的浓度，但不在生物膜中积累。DDBAC对生物膜功能和结构有负面影响。2天后，光合活性被抑制>90%，与对照组相比，并且在实验期间没有恢复。生物膜成分也受到影响，在DDBAC暴露下，绿藻明显减少，微动物消失。在DDBAC暴露改变叶绿体和叶绿素含量的情况下，藻类细胞的完整性受到损害。对自养生物的影响也通过脂质分布的变化观察到，特别是注意到糖脂含量的强烈降低。我们发现ALAN和DDBAC对研究的终点没有显著的交互作用。
