The impact of iron oxide magnetic nanoparticles on the soil bacterial community
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- Cite this article as:
- He, S., Feng, Y., Ren, H. et al. J Soils Sediments (2011) 11: 1408. doi:10.1007/s11368-011-0415-7
Iron oxide magnetic nanoparticles (IOMNPs) have numerous exciting applications due to their unique chemical and physical properties. With increased applications of engineered nanostructures, releases of such materials to soil are undoubtedly inevitable. Their potential environmental risks have attracted increasing concern. One area of concern is their effect on microorganisms, which are important components of ecosystems.
Materials and methods
In this work, the effect of IOMNPs (Fe3O4 and γ-Fe2O3) on the soil bacterial community has been studied with molecular approaches and enzyme analyses. The community structure and population size were analysed using molecular-based methods, including PCR-denaturing gradient gel electrophoresis and real-time quantitative PCR based on the universal bacterial biomarker, the 16S rRNA gene sequence fragment for the bacterial variable V3 region. In addition, plate counting was conducted to validate the results of molecular methods. Four enzyme activities (dehydrogenase, urease, invertase and phosphatase) involved in cycling the main biologically important nutrients (C, N and P) were measured.
Results and discussion
Our analysis revealed that the addition of IOMNPs could potentially stimulate some bacterial growth and change the soil bacterial community structure, although bacterial abundance does not change. Based on molecular fingerprinting and sequencing analysis, several potential IOMNPs-stimulated bacteria were related to Actinobacteria, such as Duganella, Streptomycetaceae or Nocardioides. Meanwhile, soil urease and invertase activities significantly increased under IOMNPs amendment, which could be a consequence of the changes in the bacterial community.
Molecular evidence suggests that IOMNP addition may facilitate C and N cycling in soil by influencing soil bacterial community. These findings are of great help towards building a comprehensive understanding of the potential impact of nanoparticles on the environment.