The continent-scale variations in soil microbial respiration in
forest ecosystems: diverged pattern and mechanism
Peng Tian 1,2, Xuechao Zhao 2,3,
Shengen Liu 2, Zhaolin Sun 2,3,
Yanli Jing2, Qingkui Wang 1,2
1 School of Forestry & Landscape Architecture, Anhui
Agricultural University, Hefei 230036 China
2 Huitong Experimental Station of Forest Ecology, CAS
Key Laboratory of Forest Ecology and Management, Institute of Applied
Ecology, Shenyang 110016 China
3 University of Chinese Academy of Sciences, Beijing
100049 China
Running title : Spatial variation in Rm at different scales
Abstract :
Globally rising soil microbial respiration (Rm) is a key process
controlling the soil-to-atmosphere CO2 flux, yet its
spatial variation and underlying mechanism at different scales is still
poorly understood. A novel experiment based on the annual mean
temperature of soil origin sites along a 4,200 km north–south transect
of China forests revealed a hump-shaped relationship between Rm and
latitude with a latitudinal threshold of 32.5°N. Microbial variables
were more important in shaping Rm’ spatial variation at the continental
scale than at the regional scales, but soil physicochemical property had
comparably unique importance at different scales. Labile organic C was
the most important factor in regulating the Rm’s variation at the
continent and in the latitude > 32.5°N region, but fungi
biomass was the most important factor in the latitude < 32.5°N
region. Overall, our findings suggest different controlling factors of
Rm’s variations on either side of the latitudinal threshold.
Keywords: heterotrophic respiration, soil organic carbon
decomposition, spatial pattern, latitudinal threshold, labile organic
carbon, soil microbial community