Peer Review #2 of "Drought-induced reduction in methane fluxes and its hydrothermal sensitivity in alpine peatland (v0.1)"

Abstract

Accurate estimation of CH 4 fluxes in alpine peatland of the Qinghai-Tibetan Plateau under extreme drought is vital for understanding the global carbon cycle and predicting future climate change. However, studies on the impacts of extreme drought on peatland CH 4 fluxes are limited. To study the effects of extreme drought on CH 4 fluxes of the Zoige alpine peatland ecosystem, the CH 4 fluxes during both extreme drought treatment (D) and control treatment (CK) were monitored using a static enclosed chamber in a control platform of extreme drought. The results showed that extreme drought significantly decreased CH 4 fluxes in the Zoige alpine peatland by 31.54% (P<0.05). Extreme drought significantly reduced the soil water content (SWC) (P<0.05), but had no significant effect on soil temperature (Ts). Under extreme drought and control treatments, there was a significant negative correlation between CH 4 fluxes and environmental factors (Ts and SWC), except Ts, at a depth of 5cm (P<0.05). Extreme drought reduced the correlation between CH 4 fluxes and environmental factors and significantly weakened the sensitivity of CH 4 fluxes to SWC (P<0.01). Moreover, it was found that the correlation between subsoil (20 cm) environmental factors and CH 4 fluxes was higher than with the topsoil (5, 10 cm) environmental factors under the control and extreme drought treatments. These results provide a better understanding of the extreme drought effects on CH 4 fluxes of alpine peatland, and their hydrothermal impact factors, which provides a reliable reference for peatland protection and management.