Response of a methane-driven interaction network to stressor intensification

Area of Science:

• Microbiology
• Environmental Science
• Ecology

Background:

• Microbial communities form interdependent networks influencing ecosystem functions.
• Methanotrophic interaction networks are hypothesized to enhance methane oxidation and provide benefits to methanotrophs.
• The role of these networks under stress and their response to stressors require empirical validation.

Purpose of the Study:

• To investigate the response of a methane-driven microbial interaction network to increasing ammonium chloride (NH4Cl) induced stress.
• To determine how community structure and function are altered by stress intensification.
• To elucidate the role of non-methanotrophs within the interaction network under stress.

Main Methods:

• Enrichment of a natural paddy soil microbial community in laboratory incubations.
• Stepwise increase of NH4Cl concentration to induce varying levels of stress.
• Analysis of microbial community structure using 16S rRNA and pmoA gene sequencing.
• Construction and analysis of microbial co-occurrence networks based on 16S rRNA data.

Main Results:

• Methanotrophic activity persisted at high ammonium levels, though significantly reduced.
• Community composition diverged significantly between stressed and unstressed incubations.
• Increased NH4Cl stress led to a less complex and modular co-occurrence network, indicating less stable interactions.
• Non-methanotrophs were identified as key nodes in the interaction network.

Conclusions:

• Microbial interaction networks are sensitive to ammonium-induced stress, with stress leading to network simplification.
• Non-methanotrophs play a critical role in the functioning of methane-driven microbial communities.
• Stressor intensification can unravel microbial interaction networks, negatively impacting overall community functioning.