title: Regional variation in the temperature sensitivity of soil organic matter decomposition in China's forests and grasslands.
abstract: How to assess the temperature sensitivity (Q10) of soil organic matter (SOM) decomposition and its regional variation with high accuracy is one of the largest uncertainties in determining the intensity and direction of the global carbon (C) cycle in response to climate change. In this study, we collected a series of soils from 22 forest sites and 30 grassland sites across China to explore regional variation in Q10and its underlying mechanisms. We conducted a novel incubation experiment with periodically changing temperature (5-30 °C), while continuously measuring soil microbial respiration rates. The results showed that Q10varied significantly across different ecosystems, ranging from 1.16 to 3.19 (mean 1.63). Q10was ordered as follows: alpine grasslands (2.01) > temperate grasslands (1.81) > tropical forests (1.59) > temperate forests (1.55) > subtropical forests (1.52). The Q10of grasslands (1.90) was significantly higher than that of forests (1.54). Furthermore, Q10significantly increased with increasing altitude and decreased with increasing longitude. Environmental variables and substrate properties together explained 52% of total variation in Q10across all sites. Overall, pH and soil electrical conductivity primarily explained spatial variation in Q10. The general negative relationships between Q10and substrate quality among all ecosystem types supported the C quality temperature (CQT) hypothesis at a large scale, which indicated that soils with low quality should have higher temperature sensitivity. Furthermore, alpine grasslands, which had the highest Q10, were predicted to be more sensitive to climate change under the scenario of global warming.
authors.affiliation: Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, China.|College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, 100190, China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, China.|College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, 100190, China.
authors.forename: Nianpeng
authors.identifier: 0000-0002-0458-5953
authors.initials: N
authors.lastname: He
authors.affiliation: Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, China.|College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, 100190, China.
authors.forename: Jianxing
authors.initials: J
authors.lastname: Zhu
authors.affiliation: Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, China.|College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, 100190, China.
authors.forename: Li
authors.initials: L
authors.lastname: Xu
authors.affiliation: Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, China.
authors.forename: Guirui
authors.initials: G
authors.lastname: Yu
authors.affiliation: Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, China.
authors.forename: Shuli
authors.initials: S
authors.lastname: Niu
authors.affiliation: Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, China.
authors.forename: Xiaomin
authors.initials: X
authors.lastname: Sun
authors.affiliation: Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, China.|College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, 100190, China.
authors.forename: Xuefa
authors.initials: X
authors.lastname: Wen
mesh_terms: D002244:Carbon; D057486:Carbon Cycle; D002681:China; D057231:Climate Change; D065928:Forests; D065948:Grassland; D012987:Soil / Q000737:chemistry*; D013696:Temperature
chemical_list: D012987:Soil; D002244:Carbon
keywords: decomposition; forest; grassland; regional variation; soil organic matter; temperature sensitivity