[Elevational Pattern and Control Factors of Soil Microbial Carbon Use Efficiency in the Daiyun Mountain]

Microbial carbon use efficiency (CUE) refers to the C transformation to microbial biomass from C uptake. The study of soil microbial CUE is very important for understanding the soil C cycle. Here, CUE, C_growth, and C_respiration were measured using the ¹⁸O-H₂O-DNA labeling method at six elevational sites (980-1765 m) in Daiyun Mountain, a subtropical montane forest, to understand the variation characteristics and influencing mechanisms. The results showed that:CUE varied from 0.1 to 0.4 and increased linearly with elevation; CUE was positively correlated with C_growth, C_respiration, and q_growth but negatively correlated with qCO₂, indicating that CUE increased with elevation by increasing microbial growth and inhibiting respiration; and temperature was the first controlling factor for the elevation variation in microbial CUE in the subtropical forest ecosystem.