Elevated tropospheric CO(2) and O(3) concentrations impair organic pollutant removal from grassland soil

The concentrations of tropospheric CO(2) and O(3) have been rising due to human activities. These rising concentrations may have strong impacts on soil functions as changes in plant physiology may lead to altered plant-soil interactions. Here, the effects of eCO(2) and eO(3) on the removal of polycyclic aromatic hydrocarbon (PAH) pollutants in grassland soil were studied. Both elevated CO(2) and O(3) concentrations decreased PAH removal with lowest removal rates at elevated CO(2) and elevated O(3) concentrations. This effect was linked to a shift in soil microbial community structure by structural equation modeling. Elevated CO(2) and O(3) concentrations reduced the abundance of gram-positive bacteria, which were tightly linked to soil enzyme production and PAH degradation. Although plant diversity did not buffer CO(2) and O(3) effects, certain soil microbial communities and functions were affected by plant communities, indicating the potential for longer-term phytoremediation approaches. Results of this study show that elevated CO(2) and O(3) concentrations may compromise the ability of soils to degrade organic pollutants. On the other hand, the present study also indicates that the targeted assembly of plant communities may be a promising tool to shape soil microbial communities for the degradation of organic pollutants in a changing world.