Understanding the temperature sensitivity (Q_(10)) of soil carbon (C) decomposition and the driving forces is vital for projecting soil C dynamics under climate warming. However, it is unclear of the geographic patter...Understanding the temperature sensitivity (Q_(10)) of soil carbon (C) decomposition and the driving forces is vital for projecting soil C dynamics under climate warming. However, it is unclear of the geographic patterns in Q_(10) and its driving forces in water-limited regions. We measured Q_(10) of C decomposition and multiple facets of both C quality and microbial properties, including microbial diversity, abundance, composition, activity, and trophic strategy from two soil depths (0−10 cm, 30−50 cm) collected at 38 sites along a 2000-km transect in northern China’s deserts. Q_(10) ranged in 1.56−4.80 and was significantly higher in the top (3.21) than deep soil (2.61). The large variation in Q_(10) is directly determined by microorganisms, rather than C quality which is the ratio of microbial C decomposition rate over soil organic C content. Microbial diversity, the ratio of fungi to bacterial abundance (F:B), and mass-specific respiration (qCO_(2)) were driving forces for spatial variation in Q_(10). Microbial diversity negatively impacted Q_(10), while higher F:B and qCO_(2) stimulated Q_(10). Higher C quality indirectly inhibited Q_(10) by improving microbial diversity, and decreasing F:B and qCO_(2). Our study demonstrates that microorganisms drive the geographic variations in Q_(10).展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.32171643,U1703332,41671115,and 31570455).
文摘Understanding the temperature sensitivity (Q_(10)) of soil carbon (C) decomposition and the driving forces is vital for projecting soil C dynamics under climate warming. However, it is unclear of the geographic patterns in Q_(10) and its driving forces in water-limited regions. We measured Q_(10) of C decomposition and multiple facets of both C quality and microbial properties, including microbial diversity, abundance, composition, activity, and trophic strategy from two soil depths (0−10 cm, 30−50 cm) collected at 38 sites along a 2000-km transect in northern China’s deserts. Q_(10) ranged in 1.56−4.80 and was significantly higher in the top (3.21) than deep soil (2.61). The large variation in Q_(10) is directly determined by microorganisms, rather than C quality which is the ratio of microbial C decomposition rate over soil organic C content. Microbial diversity, the ratio of fungi to bacterial abundance (F:B), and mass-specific respiration (qCO_(2)) were driving forces for spatial variation in Q_(10). Microbial diversity negatively impacted Q_(10), while higher F:B and qCO_(2) stimulated Q_(10). Higher C quality indirectly inhibited Q_(10) by improving microbial diversity, and decreasing F:B and qCO_(2). Our study demonstrates that microorganisms drive the geographic variations in Q_(10).
