Soil fauna-microbial interactions shifts fungal and bacterial communities under a contamination disturbance

The aim of this study was to determine whether the soil faunal-microbial interaction complexity (SFMIC) is a significant factor influencing the soil microbial communities and the willow growth in the context of PAH contamination. The SFMIC treatment had eight levels: just the microbial community, or the microbial community with nematodes, springtails, earthworms and all the possible combinations. SFMIC affected the height and biomass of willows after eight weeks or growth. SFMIC affected the structure and the composition of the bacterial, archaeal and fungal communities, with significant effects of SFMIC on the relative abundance of fungal genera such as Sphaerosporella, a known willow symbiont during phytoremediation, and bacterial phyla such as Actinobacteriota, containing many polycyclic aromatic hydrocarbons (PAH) degraders. These SFMIC effects on microbial communities were not clearly reflected in the community structure and abundance of PAH degraders, even though some degraders related to Actinobacteriota and the diversity of Gram-negative degraders were affected by the SFMIC treatments. Over 95% of PAH was degraded in all pots at the end of the experiment. Overall, our results suggest that, under our experimental conditions, SFMIC changes willow phytoremediation outcomes.

Automated summary

This study aimed to investigate the impact of soil faunal-microbial interaction complexity (SFMIC) on soil microbial communities and willow growth, particularly in the context of PAH contamination. The results showed that SFMIC had significant effects on the height and biomass of willows, as well as the structure and composition of bacterial, archaeal, and fungal communities. Certain fungal genera known to be willow symbionts during phytoremediation, such as Sphaerosporella, and bacterial phyla containing PAH degraders, such as Actinobacteriota, were significantly affected by SFMIC. However, the abundance and structure of PAH degraders were not clearly influenced by SFMIC treatments. Overall, the findings suggest that SFMIC can alter the outcomes of willow phytoremediation under the experimental conditions.