Regional variation in the temperature sensitivity of soil organic matter decomposition in China's forests and grasslands
Citations Over TimeTop 10% of 2017 papers
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 Q10 and 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 Q10 varied significantly across different ecosystems, ranging from 1.16 to 3.19 (mean 1.63). Q10 was ordered as follows: alpine grasslands (2.01) > temperate grasslands (1.81) > tropical forests (1.59) > temperate forests (1.55) > subtropical forests (1.52). The Q10 of grasslands (1.90) was significantly higher than that of forests (1.54). Furthermore, Q10 significantly increased with increasing altitude and decreased with increasing longitude. Environmental variables and substrate properties together explained 52% of total variation in Q10 across all sites. Overall, pH and soil electrical conductivity primarily explained spatial variation in Q10 . The general negative relationships between Q10 and 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.
Related Papers
- → Research progress on the responses of soil respiration components to climatic warming.(2018)3 cited
- → Columbus's Method of Determining Longitude: An Analytical View(1996)7 cited
- → The accuracy of longitude determinations by the U.S. Coast And Geodetic Survey by wire signals and general Ferrié's proposed radio longitude net(1923)
- → Use of the gravity pendulum as a timepiece for longitude determinations(1926)
- → Longitude variations of solar magnetic fields of different intensity in cycle 23 as inferred from the SOHO/MDI data(2011)