Titanium dioxide nanoparticles strongly impact soil microbial function by affecting archaeal nitrifiers

Marie Simonin (1, 2, 3, 4, 5) , Agnès Richaume-Jolion (1, 2, 3) , Julien P. Guyonnet (1, 2, 3) , Audrey Dubost (1, 2, 3) , Jean M. F. Martins (3, 6) , Thomas Pommier (1, 2, 3)

1 LEM - Laboratoire d'Ecologie Microbienne - UMR 5557
2 UCBL - Université Claude Bernard Lyon 1
3 CNRS - Centre National de la Recherche Scientifique
4 Center for the Environmental Implications of Nanotechnology
5 Department of Biology
6 OSUG - Observatoire des Sciences de l'Univers de Grenoble

Soils are facing new environmental stressors, such as titanium dioxide nanoparticles (TiO2-NPs). While these emerging pollutants are increasingly released into most ecosystems, including agricultural fields, their potential impacts on soil and its function remain to be investigated. Here we report the response of the microbial community of an agricultural soil exposed over 90 days to TiO2-NPs (1 and 500 mg kg(-1) dry soil). To assess their impact on soil function, we focused on the nitrogen cycle and measured nitrification and denitrification enzymatic activities and by quantifying specific representative genes (amoA for ammonia-oxidizers, nirK and nirS for denitrifiers). Additionally, diversity shifts were examined in bacteria, archaea, and the ammonia-oxidizing clades of each domain. With strong negative impacts on nitrification enzyme activities and the abundances of ammonia-oxidizing microorganism, TiO2-NPs triggered cascading negative effects on denitrification enzyme activity and a deep modification of the bacterial community structure after just 90 days of exposure to even the lowest, realistic concentration of NPs. These results appeal further research to assess how these emerging pollutants modify the soil health and broader ecosystem function.

Domaines: Sciences du Vivant [q-bio]

Marie Simonin, Agnès Richaume-Jolion, Julien P. Guyonnet, Audrey Dubost, Jean M. F. Martins, et al.. Titanium dioxide nanoparticles strongly impact soil microbial function by affecting archaeal nitrifiers. Scientific Reports, 2016, 6, pp.1-10. ⟨10.1038/srep33643⟩. ⟨hal-01602239⟩