title: Chronic Exposure Effects of Silver Nanoparticles on Stream Microbial Decomposer Communities and Ecosystem Functions.
abstract: 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.
authors.affiliation: 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.
authors.forename: Ahmed
authors.identifier: 0000-0003-1645-0711
authors.initials: A
authors.lastname: Tlili
authors.affiliation: Department of Experimental Limnology, Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB) , 16775 Stechlin, Germany.
authors.forename: Jérémy
authors.initials: J
authors.lastname: Jabiol
authors.affiliation: Department of Environmental Toxicology, Eawag: Swiss Federal Institute of Aquatic Science and Technology , 8600 Dübendorf, Switzerland.
authors.forename: Renata
authors.initials: R
authors.lastname: Behra
authors.affiliation: Department of Environmental Toxicology, Eawag: Swiss Federal Institute of Aquatic Science and Technology , 8600 Dübendorf, Switzerland.
authors.forename: Carmen
authors.initials: C
authors.lastname: Gil-Allué
authors.affiliation: Department of Experimental Limnology, Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB) , 16775 Stechlin, Germany.|Department of Ecology, Berlin Institute of Technology (TU Berlin) , 10623 Berlin, Germany.
authors.forename: Mark O
authors.initials: MO
authors.lastname: Gessner
mesh_terms: D017753:Ecosystem; D005658:Fungi / Q000187:drug effects; D053758:Nanoparticles; D018515:Plant Leaves / Q000737:chemistry; D045483:Rivers / Q000382:microbiology*; D012834:Silver / Q000633:toxicity*
chemical_list: D012834:Silver