Environmental context determines pollution impacts on ecosystem functioning

Global change assessments have typically ignored synthetic chemical pollution, despite the rapid increase of pharmaceuticals, pesticides, and industrial chemicals in the environment. Part of the problem reflects the multifarious origins of these micropollutants, which can derive from urban and agricultural sources. Understanding how micropollutants harm ecosystems is a major scientific challenge due to asymmetries of stress across trophic levels and ecological surprises generated by multiple drivers interacting in human-impacted landscapes. We used field assays above and below municipal wastewater treatment plants (WWTPs) in 60 sampling locations across 20 Swiss streams to test how micropollutants and nutrients originating from WWTPs affect two trophic levels (microbes and detritivores) and their role in leaf litter processing. Wastewater impacts were asymmetric across trophic levels, with the detritivore contribution declining relative to microbial-driven decomposition. The strength of...尽管环境中药物、农药与工业化学品的含量正快速攀升，但全球变化评估通常未将合成化学污染纳入考量范畴。造成这一疏漏的部分原因在于，这类微污染物（micropollutants）来源繁杂多样，可源自城市与农业活动排放。由于不同营养级（trophic levels）间的胁迫不对称性，以及多驱动因子在受人类活动干扰的景观中交互作用所引发的非预期生态响应，阐明微污染物如何损害生态系统是一项重大科学难题。本研究于瑞士20条溪流的60个采样点位，在城市污水处理厂（municipal wastewater treatment plants, WWTPs）上下游开展野外实验（field assays），以探究污水处理厂排放的微污染物与营养盐如何影响两个营养级：微生物与食碎屑生物（detritivores），及其在凋落叶分解过程（leaf litter processing）中的作用。研究结果显示，污水处理厂的排放影响在不同营养级间呈现不对称性：相较于微生物驱动的分解过程，食碎屑生物的贡献显著下降。其影响强度的……