Response of bacterioplankton to gold and copper nanoparticle additions in wetland mesocosms and microcosms Raw sequence reads

From both mesocosms and microcosms experiments, we found that CuNPs and AuNPs both exert significant effects on microbial communities, but with different mechanisms. CuNPs might directly target several microbial taxa sensitive to Cu, while AuNPs, although has been perceived as inert and much less toxic to microbes, did exhibit a significant effect on microbial community in highly simplified microcosms. However, this effect can be easily diminished or complexed as ecosystem complexity increases: supported by both the minimal effect in wetland mesocosms as well as in microcosms with Egeria. We speculate this buffering effect by Egeria (and by all other organisms in a complex ecosystem), may be attributed to both their transformation and bio-accumulation of AuNP, and their influence on the concentration and composition of organic matters in water. Even though widespread environmental exposure of AuNP is unlikely, our study highlights the importance of considering multiple abiotic and biotic factors while analyzing microbial responses to emerging contaminants, and the limited power of using simplified experiments to predict ecological impacts in an environmental context.