n-Alkane Gradients Reshape Soil Microbial Networks and Functions at Petroleum Refinery Sites

Area of Science:

• Environmental Science
• Microbiology
• Soil Science

Background:

• Petroleum refining poses significant risks to soil ecosystems.
• Microbial responses to petroleum contamination are not fully understood.
• Soil microbial adaptations are crucial for ecosystem health.

Purpose of the Study:

• To investigate microbial adaptation mechanisms in petroleum-contaminated soils.
• To elucidate the impact of petroleum pollution on soil microbial communities and functions.
• To provide insights for developing effective bioremediation strategies.

Main Methods:

• Source apportionment to identify petroleum influence.
• High-throughput sequencing for microbial community analysis.
• Co-occurrence network analysis to study microbial interactions.
• Analysis of soil physicochemical properties and soil quality index (SQI).

Main Results:

• Petroleum pollution significantly increased hydrocarbon concentrations and altered soil physicochemical properties, including total organic carbon (TOC).
• Microbial functional diversity showed convergence under stress, with low exposure stimulating naphthalene degradation and high exposure inducing oxidative stress resistance.
• Microbial networks evolved from complex and sensitive to simplified and robust structures with increasing contamination.
• The soil quality index (SQI) showed a nonlinear trend, indicating complex environmental effects.

Conclusions:

• Soil microbial communities exhibit adaptive strategies to petroleum contamination, including functional convergence and network restructuring.
• Metabolic pathways shift from degradation to stress resistance with increasing pollution levels.
• These findings offer mechanistic insights into microbial adaptation and support the development of soil bioremediation approaches for petroleum-contaminated sites.