Effects Of Oxide Nanoparticles On Microbial Community Structure And Function In Two Different Soil Types

Oxide nanoparticles have widespread applications due to their unique chemical and physical properties.With widely applications of nanostructures,of which releases to soil are undoubtedly inevitable.Because soil microbial communities play vital roles in many of the biogeochemical processes on Earth,it is critical to study the effects of ENP exposure on soil microbial communities.To indicate the effects,we simulated the soil environmental conditions exposed by oxide nanomaterials,and used three typical oxide nanomaterials（Cu O,SiO₂ and Al₂O₃ nanomaterials）as the research object to determine the response of soil enzyme activity through 15-day and 30-day incubation in two soil types（black soil and and saline-alkali soil）treated with different concentrations of oxide nanoparticles(0.5,1.0 or 2.0 mg·g-1.,and to determine the response of soil bacterial community structure through 15-day and 30-day incubation in two soil types（black soil and and saline-alkali soil）treated with the highest concentrations of nCuO（2.0 mg·g-1）,to reveal the relationship between the oxide nanomaterials and the soil microbial community at different scales,scientifically assess the soil environmental ecological and health risks of the oxide nanomaterials,and provide a theoretical basis for the soil ecological risk management for the leakage of nanomaterials,further promote the healthy and sustainable development of nanotechnology.The main findings are as follows:（1）Soil enzyme activity is different for different nanomaterials.CuO nanomaterials have the greatest toxicity to soil enzyme activity.followed by.SiO₂ nanomaterials,and Al₂O₃ nanomaterials have the least inhibitory effect on soil enzyme activity.（2）The effect of nanomaterials on soil enzyme activity showed a dose-dependent effect,and enhanced with the increase of the concentration.（3）The inhibitory effect of Al₂O₃ nanomaterials on the urease inhibition in black soil is short,indicating that the soil microbial community may produce a tolerance mechanism for the treatment of nanomaterials during the culture process.（4）The promotion of SiO₂ nanomaterials on the phosphatase activity and its inhibition on catalase activity in black soil was only observed in the presence of nanomaterials for a long time（30 day）,which indicated that lattice may have an effect on the activity of nanomaterials（5）Compared with black soil,soil enzyme activity in saline soil is more susceptible to nanomaterials.（6）In saline-alkali soil,CuO nanomaterials reduced the size and diversity of soil bacterial communities,but had no significant effect on soil bacterial community size and diversity.（7）CuO nanomaterials changed the composition of soil microbial communities in the two soil types,but the species composition varied with each other.In saline-alkali soil,the effect of copper oxide nanomaterials on soil bacterial community was dominated by inhibition,nevertheless in the black soil,the copper oxide nanomaterials showed a tolerance effect and a promoting effect on the vast majority of bacterial communities.