Variations of temperature and photoperiod throughout different seasons can affect aquatic communities such as biofilms. Biofilms, generally present at the base of trophic chains in freshwaters, are also subject to organic contamination, and are especially affected by herbicides. Many studies have investigated the effect and interactions of herbicides and environmental factors on biofilms, but never with a toxicokinetic point of view. The objective of this study was to assess structural and functional changes in biofilms exposed to diuron, and to link them with contaminant accumulation, under the influence of temperature and light variations. To this aim, biofilms were exposed to all possible combinations of three concentrations (0, 5 and 50 µg L-1) of diuron, two temperatures (10 and 26 °C), and two light/dark photoperiods (16/8, 10/14), for durations of 0, 1 and 3 days. Diuron accumulation in biofilms was quantified and structural descriptors (protein and polysaccharide contents, dry weight) and functional endpoints (photosynthetic and enzymatic activities) were analyzed. The results obtained mainly highlighted the influence of temperature on diuron bioaccumulation and the associated toxic impact on biofilms. Bioaccumulation in biofilms exposed during three days at 10 °C, at the highest diuron concentration, was in average 1.4 times higher than bioaccumulation on biofilms exposed to 26 °C. Accordingly, the photosynthetic yield was more inhibited at lower than at higher temperatures. Temperature was also the highest impacting factor for metabolism regulation; for example, at 26 °C after three days of exposure, polysaccharide production was boosted under both photoperiods tested.

中文翻译：

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光照和温度会影响敌草隆的生物积累和生物膜的毒性。

整个季节的温度和光周期的变化都会影响水生生物群落，例如生物膜。通常存在于淡水中营养链底部的生物膜也容易受到有机污染，尤其受到除草剂的影响。许多研究已经研究了除草剂和环境因素对生物膜的影响和相互作用，但从未以毒物动力学的观点进行研究。这项研究的目的是评估在温度和光照变化的影响下，暴露于敌草隆的生物膜的结构和功能变化，并将其与污染物积累联系起来。为此，将生物膜暴露于三种浓度（0、5和50 µg L-1）的敌草隆，两种温度（10和26°C）和两种明/暗光周期（16 / 8、10）的所有可能组合下/ 14），持续时间为0、1和3天。定量生物膜中敌草隆的积累，并分析结构描述符（蛋白质和多糖含量，干重）和功能终点（光合和酶活性）。获得的结果主要强调温度对敌草隆生物积累的影响以及对生物膜的相关毒性影响。在最高杜伦浓度下，在10°C下三天暴露于生物膜中的生物累积量平均比暴露于26°C的生物膜上的生物累积量高1.4倍。因此，在较低的温度下比在较高的温度下光合产量受到更大的抑制。温度也是影响代谢调节的最高因素。例如，在暴露三天后在26°C下，两种测试的光周期都能提高多糖产量。