Department of Experimental Limnology, Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB) , 16775 Stechlin, Germany.
Department of Environmental Toxicology, Eawag: Swiss Federal Institute of Aquatic Science and Technology , 8600 Dübendorf, Switzerland.
Environ Sci Technol. 2017 Feb 21;51(4):2447-2455. doi: 10.1021/acs.est.6b05508. Epub 2017 Feb 2.
With the accelerated use of silver nanoparticles (AgNP) in commercial products, streams will increasingly serve as recipients of, and repositories for, AgNP. This raises concerns about the potential toxicity of these nanomaterials in the environment. Here we aimed to assess the impacts of chronic AgNP exposure on the metabolic activities and community structure of fungal and bacterial plant litter decomposers as central players in stream ecosystems. Minimal variation in the size and surface charge of AgNP indicated that nanoparticles were rather stable during the experiment. Five days of exposure to 0.05 and 0.5 μM AgNP in microcosms shifted bacterial community structure but had no effect on a suite of microbial metabolic activities, despite silver accumulation in the decomposing leaf litter. After 25 days, however, a broad range of microbial endpoints, as well as rates of litter decomposition, were strongly affected. Declines matched with the total silver concentration in the leaves and were accompanied by changes in fungal and bacterial community structure. These results highlight a distinct sensitivity of litter-associated microbial communities in streams to chronic AgNP exposure, with effects on both microbial functions and community structure resulting in notable ecosystem consequences through impacts on litter decomposition and further biogeochemical processes.
随着银纳米粒子（AgNP）在商业产品中的加速使用，溪流将越来越成为 AgNP 的接受者和储存库。这引发了人们对这些纳米材料在环境中潜在毒性的担忧。在这里，我们旨在评估慢性 AgNP 暴露对真菌和细菌植物凋落物分解者代谢活性和群落结构的影响，这些分解者是溪流生态系统中的核心参与者。AgNP 的大小和表面电荷变化很小，表明在实验过程中纳米颗粒相当稳定。在微宇宙中暴露于 0.05 和 0.5 μM AgNP 5 天，改变了细菌群落结构，但对一系列微生物代谢活性没有影响，尽管分解落叶中的银积累。然而，25 天后，广泛的微生物终点以及凋落物分解速率受到强烈影响。下降与叶片中的总银浓度相匹配，并伴随着真菌和细菌群落结构的变化。这些结果突出表明，溪流中与凋落物相关的微生物群落对慢性 AgNP 暴露具有明显的敏感性，对微生物功能和群落结构的影响通过对凋落物分解和进一步生物地球化学过程的影响导致显著的生态后果。
