Visual data exploration of soil bacteria susceptible to engineered nanomaterials

The impact of ZnO and TiO₂ nanoparticles (NPs) on soil bacterial communities for different exposure times and NP doses was explored via data visualization techniques. Interrelationships between NP and responses of bacterial taxa were illustrated by bipartite graphs, allowing fast identification of important soil bacterial taxa that are susceptible to NPs. Hierarchical clustering and nonmetric multi-dimensional scaling (NMDS) of the dataset demonstrated that, high dose of ZnO and TiO₂ NPs caused significant compositional changes in soil bacterial communities. The suitability of family level for NP impact assessment was demonstrated by the simplified NMDSs and the distance correlation between NP impacts summarized at different taxonomic levels. The present study demonstrates that visual exploration could potentially assist in knowledge discovery and interpretation of data on soil bacterial communities exposed to NPs and thus evaluate potential environmental impacts.