Keystone Microorganisms Regulate the Methanogenic Potential in Coals with Different Coal Ranks

Area of Science:

• Microbial ecology
• Biogeochemistry
• Geomicrobiology

Background:

• Microorganisms drive coal biogeochemistry and coalbed methane formation.
• The microbial network structure and stability in coals of varying ranks are poorly understood.

Purpose of the Study:

• To investigate microbial co-occurrence networks and their stability across different coal ranks (anthracite, medium-volatile bituminous, high-volatile bituminous).
• To identify keystone taxa and their role in microbial community stability and methanogenic potential.

Main Methods:

• High-throughput sequencing data analysis.
• Microbial co-occurrence network construction and topological analysis.
• Identification of keystone taxa within network modules.
• Partial least-squares path modeling to assess relationships between keystone taxa, community stability, diversity, and methanogenic potential.

Main Results:

• Microbial networks exhibited similar topological properties but distinct microbial compositions across coal ranks.
• Forty-six keystone taxa were identified, varying by coal rank, with bacteria (Actinobacteria, Bacteroidetes, Firmicutes, Proteobacteria) dominating.
• Removal of keystone taxa reduced community stability in bituminous coals.
• Keystone taxa indirectly influenced methanogenic potential by enhancing community stability and bacterial diversity.

Conclusions:

• Keystone taxa are vital for microbial community diversity and stability in coal seams.
• These keystone taxa play a significant role in controlling coalbed methane production.
• Findings advance understanding of microbial ecology and geochemical cycles within coal seams.