Oil sands process affected water and sediments  - Raw sequence reads
Plants and microorganisms can break down many contaminants, including naphthenic acid fraction compounds (NAFCs) ; the primary toxic contaminants in oil sands process-affected water (OSPW). One way to take advantage of these processes is to use constructed wetland treatment systems (CWTSs), where aquatic plants work in coordination with microorganisms to contribute to remediation of OSPW. However, the dynamics of the microbial communities and the potential contribution of distinct bacteria, fungi and eukaryotes inhabiting sediments, rhizosphere and water that comprise these systems remain poorly understood. We planted water sedge (Carex aquatilis) in mesocosm-scale wetland systems and compared to unplanted controls. Naphthenic acid fraction compounds (NAFCs) concentrations and microbial community dynamics among various mesocosm compartments were monitored using mass spectrometry and high-throughput sequencing of the prokaryotic 16S rRNA gene, the fungal ITS2 region and eukaryotic 18S rRNA gene. Carex-planted mesocosms reduced NAFCs concentrations more rapidly than the unplanted controls, which coincided with shifts in abundance for both bacterial and fungal communities, especially in the Carex rhizosphere and sediment communities. The strongest relationships between microbial taxa and the decrease in NAFCs concentrations were for anaerobic bacteria, suggesting a prominent role for these bacteria in NAFCs degradation in CWTS. This study highlights potential microbial targets for improving CWTS efficiency for NAFCs detoxification during OSPW remediation.