Polycyclic Aromatic Hydrocarbon Pollution Stress Impairs Soil Enzyme Activity and Microbial Community

Area of Science:

• Environmental Science
• Soil Microbiology
• Ecotoxicology

Background:

• Polycyclic aromatic hydrocarbons (PAHs) are pervasive organic pollutants with detrimental environmental effects.
• Soil microbial communities are crucial for ecosystem health and function, influencing nutrient cycling and soil quality.
• Understanding the impact of PAHs on soil microbial ecosystems is vital for assessing environmental risks and developing remediation strategies.

Purpose of the Study:

• To investigate the effects of polycyclic aromatic hydrocarbon (PAH) contamination on soil enzymatic activities and microbial community structure.
• To evaluate changes in microbial biomass, community composition, and assembly processes under PAH stress.
• To identify specific microbial taxa and metabolic functions affected by PAH contamination.

Main Methods:

• Soil samples were analyzed 90 days after PAH contamination.
• Enzymatic activities (dehydrogenase, catalase, protease, urease) were measured.
• Microbial community structure and assembly were assessed using 16S and ITS amplicon sequencing, Beta Nearest Taxon Index, and co-occurrence network analysis.

Main Results:

• PAH stress significantly inhibited soil microbial activities, including urease, catalase, and protease.
• Bacterial and fungal biomass decreased, with an inhibition of taxa involved in carbon and nitrogen cycling.
• PAH-degrading microorganisms (e.g., Pseudomonas, Mycobacterium) were enriched, while niche breadth and microbial diversity were reduced.

Conclusions:

• PAH contamination adversely affects soil microbial communities, reducing enzymatic activities and biomass.
• PAH stress alters microbial community structure, favoring PAH degraders and reducing functional diversity.
• The findings indicate that PAH contamination profoundly impacts soil quality by restricting microbial survival and altering ecological processes.