title: Long-Term Effects of Multiwalled Carbon Nanotubes and Graphene on Microbial Communities in Dry Soil.
abstract: Little is known about the long-term effects of engineered carbonaceous nanomaterials (ECNMs) on soil microbial communities, especially when compared to possible effects of natural or industrial carbonaceous materials. To address these issues, we exposed dry grassland soil for 1 year to 1 mg g(-1) of either natural nanostructured material (biochar), industrial carbon black, three types of multiwalled carbon nanotubes (MWCNTs), or graphene. Soil microbial biomass was assessed by substrate induced respiration and by extractable DNA. Bacterial and fungal communities were examined by terminal restriction fragment length polymorphism (T-RFLP). Microbial activity was assessed by soil basal respiration. At day 0, there was no treatment effect on soil DNA or T-RFLP profiles, indicating negligible interference between the amended materials and the methods for DNA extraction, quantification, and community analysis. After a 1-year exposure, compared to the no amendment control, some treatments reduced soil DNA (e.g., biochar, all three MWCNT types, and graphene; P < 0.05) and altered bacterial communities (e.g., biochar, carbon black, narrow MWCNTs, and graphene); however, there were no significant differences across the amended treatments. These findings suggest that ECNMs may moderately affect dry soil microbial communities but that the effects are similar to those from natural and industrial carbonaceous materials, even after 1-year exposure.
authors.affiliation: State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences , Beijing 100085, China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Ge
authors.forename: John H
authors.initials: JH
authors.lastname: Priester
authors.affiliation: Laboratory of Environmental Toxicity, National Institute of Chemical Physics and Biophysics , Akadeemia tee 23, 12618 Tallinn, Estonia.
authors.forename: Monika
authors.initials: M
authors.lastname: Mortimer
authors.forename: Chong Hyun
authors.initials: CH
authors.lastname: Chang
authors.forename: Zhaoxia
authors.initials: Z
authors.lastname: Ji
authors.forename: Joshua P
authors.initials: JP
authors.lastname: Schimel
authors.forename: Patricia A
authors.initials: PA
authors.lastname: Holden
mesh_terms: D000332:Aerobiosis / Q000187:drug effects; D001419:Bacteria / Q000187:drug effects* / Q000235:genetics; D018533:Biomass; D004269:DNA, Bacterial / Q000235:genetics; D003890:Desiccation; D005658:Fungi / Q000187:drug effects*; D006108:Graphite / Q000494:pharmacology*; D037742:Nanotubes, Carbon / Q000737:chemistry* / Q000648:ultrastructure; D012150:Polymorphism, Restriction Fragment Length; D012988:Soil Microbiology; D013997:Time Factors
chemical_list: D004269:DNA, Bacterial; D037742:Nanotubes, Carbon; D006108:Graphite