Soil microbial trait-based strategies drive metabolic efficiency along an altitude gradient

Area of Science:

• Soil Ecology
• Microbial Ecology
• Biogeochemistry

Background:

• Trait-based approaches link microbial communities to ecosystem functions.
• Understanding microbial trait trade-offs in regulating metabolic efficiency is crucial but remains unclear.

Purpose of the Study:

• To investigate how microbial traits influence soil metabolic efficiency along an altitudinal gradient.
• To identify microbial attributes and assemblies associated with changes in metabolic efficiency.

Main Methods:

• Assessed soil microbial metabolic efficiency (metabolic quotient, qCO2; carbon use efficiency, CUE) along an altitude gradient.
• Correlated metabolic efficiency with microbial physiological and taxonomic traits, and environmental factors (pH, substrate).
• Identified microbial assemblies prevalent in harsh environments.

Main Results:

• Soil microbial metabolic efficiency decreased with increasing altitude (higher qCO2, lower CUE).
• Microbial physiological traits, particularly investment in nutrient acquisition enzymes (e.g., phosphorus), predicted metabolic efficiency.
• Harsh environmental conditions selected for microbial assemblies adapted to nutrient limitation and low temperatures, but with reduced metabolic efficiency.

Conclusions:

• Altitude-driven environmental changes alter soil microbial community structure and function.
• Reduced metabolic efficiency at higher altitudes is linked to microbial adaptations for nutrient acquisition in resource-limited, cold environments.
• Findings elucidate mechanisms of microbial metabolic efficiency and its implications for carbon cycling under climate change.