Biodiversity has received great attention over the past several decades, but the dimension of biodiversity has been poorly studied, especially in groundwater ecosystems. Here, we used 12 wells at the Oak Ridge Field Research Challenge site (Oak Ridge, TN, USA) to understand the phylogenetic, taxonomic, and functional diversity (PD, TD, and FD, respectively) of groundwater microbial communities and their relationships with environmental factors and ecosystem functions. Twelve wells with different concentrations of uranium (0~16 mg/L) and nitrate (0~9068 mg/L) along a pH gradient (3.43~7.28) were selected for 16S rRNA gene amplicons sequencing, aiming to characterize the groundwater community taxonomic and phylogenetic diversity, as well as investigating the community functional diversity using shot-gun metagenome sequencing and GeoChip DNA microarray.
Results/Conclusions
Preliminary analysis shows taxonomic and phylogenetic alpha diversity decrease in the contaminated wells compared with uncontaminated wells from 16S data. While no difference in functional alpha diversity is observed between contaminated wells and uncontaminated wells from GeoChip and shotgun sequencing data. NMDS ordination of taxonomic and phylogenetic beta diversity from 16S data shows microbial communities in contaminated wells are clustered, whereas communities in uncontaminated wells are separated. However, microbial communities in contaminated wells are separated from NMDS ordination of functional beta diversity of GeoChip data. Moreover, functional beta diversity in GeoChip data shows greater dispersion in contaminated wells, but taxonomic and phylogenetic beta diversity in 16S data show greater dispersion in uncontaminated wells. Preliminary results seem to indicate that groundwater microbial taxonomic and phylogenetic diversity decreases along the gradient of increasing contaminants based on the 16S data, but functional diversity does not show similar pattern from GeoChip data and shot-gun metagenome sequencing data. Several functional genes involved in heavy metal resistance and denitrification significantly increase in contaminated wells from GeoChip data. Further analysis of the relationships between microbial communities and environmental factors is underway.