Urban ecosystems are subjected to multiple anthropogenic stresses, which impact aquatic communities. Artificial light at night (ALAN) for instance can significantly alter the composition of algal communities as well as the photosynthetic cycles of autotrophic organisms, possibly leading to cellular oxidative stress. The combined effects of ALAN and chemical contamination could increase oxidative impacts in aquatic primary producers, although such combined effects remain insufficiently explored. To address this knowledge gap, a one-month experimental approach was implemented under controlled conditions to elucidate effects of ALAN and dodecylbenzyldimethylammonium chloride (DDBAC) on aquatic biofilms. DDBAC is a biocide commonly used in virucidal products, and is found in urban aquatic ecosystems. The bioaccumulation of DDBAC in biofilms exposed or not to ALAN was analyzed. The responses of taxonomic composition, photosynthetic activity, and fatty acid composition of biofilms were examined. The results indicate that ALAN negatively affects photosynthetic yield and chlorophyll production of biofilms. Additionally, exposure to DDBAC at environmental concentrations induces lipid peroxidation, with an increase of oxylipins. This experimental study provides first insights on the consequences of ALAN and DDBAC for aquatic ecosystems. It also opens avenues for the identification of new biomarkers that could be used to monitor urban pollution impacts in natural environments.

中文翻译：

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城市污染对淡水生物膜的影响：氧化应激、光合作用和脂质反应


城市生态系统受到多种人为压力的影响，从而影响水生群落。例如，夜间人造光（ALAN）可以显着改变藻类群落的组成以及自养生物的光合作用周期，可能导致细胞氧化应激。 ALAN 和化学污染的综合影响可能会增加水产初级生产者的氧化影响，尽管这种综合影响尚未得到充分探索。为了弥补这一知识差距，在受控条件下实施了为期一个月的实验方法，以阐明 ALAN 和十二烷基苄基二甲基氯化铵 (DDBAC) 对水生生物膜的影响。 DDBAC 是一种常用于杀病毒产品的杀菌剂，存在于城市水生生态系统中。分析了暴露或未暴露于 ALAN 的生物膜中 DDBAC 的生物累积情况。检查了生物膜的分类组成、光合活性和脂肪酸组成的响应。结果表明，ALAN 对生物膜的光合产量和叶绿素产生产生负面影响。此外，在环境浓度下暴露于 DDBAC 会诱导脂质过氧化，并导致氧脂质增加。这项实验研究首次揭示了 ALAN 和 DDBAC 对水生生态系统的影响。它还为识别新的生物标志物开辟了途径，这些生物标志物可用于监测城市污染对自然环境的影响。