Our knowledge of fundamental drivers of the temperature sensitivity (Q10) of soil carbon dioxide (CO2) release is crucial for improving the predictability of soil carbon dynamics in Earth System Models. However, patterns and determinants of Q10 over a broad geographic scale are not fully understood, especially in alpine ecosystems. Here we addressed this issue by incubating surface soils (0–10 cm) obtained from 156 sites across Tibetan alpine grasslands. Q10 was estimated from the dynamics of the soil CO2 release rate under varying temperatures of 5–25�C. Structure equation modeling was performed to evaluate the relative importance of substrate, environmental, and microbial properties in regulating the soil CO2 release rate and Q10. Our results indicated that steppe soils had significantly lower CO2 release rates but higher Q10 than meadow soils. The combination of substrate properties and environmental variables could predict 52% of the variation in soil CO2 release rate across all grassland sites and explained 37% and 58% of the variation in Q10 across the steppe and meadow sites, respectively. Of these, precipitation was the best predictor of soil CO2 release rate. Basal microbial respiration rate (B) was the most important predictor of Q10 in steppe soils, whereas soil pH outweighed B as the major regulator in meadow soils. These results demonstrate that carbon quality and environmental variables coregulate Q10 across alpine ecosystems, implying that modelers can rely on the “carbon-quality temperature” hypothesis for estimating apparent temperature sensitivities, but relevant environmental factors, especially soil pH, should be considered in higher-productivity alpine regions. �2016. American Geophysical Union. All Rights Reserved.
State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, Beijing, China; College of Energy and Power Engineering, Inner Mongolia University of Technology, Hohhot, China; Department of Ecology and Key Laboratory for Earth Surface Processes of the Ministry of Education, Peking University, Beijing, China; Department of Botany and Microbiology, University of Oklahoma, Norman, OK, United States
Recommended Citation:
Ding J,, Chen L,, Zhang B,et al. Linking temperature sensitivity of soil CO2 release to substrate, environmental, and microbial properties across alpine ecosystems[J]. Global Biogeochemical Cycles,2016-01-01,30(9)