Empirical evidence for glomalin-related soil protein regulation of temperature sensitivity of soil organic carbon decomposition in alpine forests

Glomalin-related soil protein (GRSP) appears to control in temperature sensitivity (Q 10 ) of soil organic carbon (SOC) decomposition. However, empirical evidence for GRSP regulation of Q 10 is still lacking, especially in subalpine forests. Here, we conducted an experiment to explore GRSP regulation of Q 10 along elevational gradients in the Qilian Mountains of China. Our results indicated that GRSP was significantly affected by elevation. In particular, extractable GRSP (EE-GRSP) and total GRSP (T-GRSP) significantly decreased as altitude increased, and their contributions to soil organic carbon (SOC) also declined. Soil pH was the most critical variable in predicting GRSP in subalpine forest ecosystems, followed by SOC. Q 10 was also significantly impacted by elevation, and soil carbon decomposed more easily at high elevations. A partial least squares path model demonstrated that the inclusion of GRSP improved the accuracy of Q 10 and suggested that a crucial reason for the increase in Q 10 with altitude was the decline in GRSP content. These results provide strong evidence for GRSP regulation of temperature sensitivity of soil organic carbon decomposition in alpine forests.