Microecological thresholds regulation by biochar boosts aged hydrocarbon degradation

Area of Science:

• Environmental Science
• Soil Science
• Microbiology

Background:

• Aged petroleum hydrocarbon (A-PHC) contamination poses environmental challenges.
• Remediation is limited by pollutant recalcitrance and soil microbial network disruption.
• Biochar amendments offer potential but require balancing contaminant adsorption and microbial biostimulation.

Purpose of the Study:

• To establish a microecological threshold framework for optimizing biochar application in A-PHC contaminated soils.
• To investigate the impact of varying biochar rates on microbial communities and A-PHC degradation.
• To understand the mechanisms driving enhanced biodegradation versus abiotic adsorption.

Main Methods:

• Investigated biochar application rates from 0% to 5.5%.
• Analyzed microbial community diversity, network architecture, and assembly processes.
• Utilized spectroscopic methods to differentiate biodegradation and adsorption.

Main Results:

• A critical biochar threshold of approximately 1% was identified.
• Optimal biochar rates (around 1%) enhanced A-PHC degradation by 50.86%-83.60% through microbial activation.
• Higher biochar rates led to microbial community collapse and stalled degradation.

Conclusions:

• The microecological threshold framework is crucial for precision bioremediation of A-PHC.
• Optimizing biochar application reconstructs functional soil microbial networks for effective degradation.
• This approach shifts focus from pollutant reduction to ecosystem network restoration.