Microbiome assembly in thawing permafrost and its feedbacks to climate

Area of Science:

• Microbial ecology
• Environmental microbiology
• Climate science

Background:

• Permafrost thaw causes physical and chemical changes, influencing microbial communities and organic matter decomposition.
• Uncertainty exists regarding microbial responses to thaw and their role in permafrost-climate feedbacks.
• Current understanding of post-thaw microbial assembly patterns across global permafrost soils is limited.

Purpose of the Study:

• To propose Assembly Theory as a framework for understanding thaw-mediated microbiome changes.
• To predict microbial community function and climate feedbacks.
• To investigate the roles of deterministic and stochastic processes in post-thaw microbiome assembly.

Main Methods:

• Literature review of Arctic microbiome, permafrost microbiology, and community ecology.
• Application of Assembly Theory principles to permafrost thaw scenarios.
• Hypothesizing the influence of thaw disturbance characteristics and microbial community traits on assembly processes.

Main Results:

• Assembly Theory can elucidate microbiome shifts and functional implications following permafrost thaw.
• Short-term, high-disturbance thaw (e.g., thermokarst) is predicted to be dominated by stochastic processes.
• Long-term, low-intensity disturbance (e.g., active layer deepening) is predicted to be dominated by deterministic processes.

Conclusions:

• The balance of stochastic and deterministic processes in post-thaw assembly depends on thaw disturbance and microbial community characteristics.
• Microbial community traits like functional redundancy and biotic interactions influence assembly.
• Understanding these processes is crucial for predicting microbial contributions to greenhouse gas feedbacks and climate change.