Temperature and Soil Moisture Interactively Affect Soil Carbon Mineralization in Zoige Alpine Wetlands

Key words: 
• alpine wetlands /
• carbon mineralization /
• marsh /
• peatland /
• soil moisture /
• temperature

Abstract: Wetlands store substantial amount of carbon and may contribute greatly to climate change. However, few studies have investigated the effects of global climate change on carbon mineralization in Zoige wetlands. By measuring CO2 and CH4 production rate from incubated, undisturbed soils, we studied the effects of temperature and soil moisture on carbon mineralization in two types of alpine wetlands (peatland and marsh) on Tibetan plateau. CO2 production rate increased about 3.3~3.7 times with temperatures from 5 oC to 35 oC in marsh soils and 2.4~2.6 times in peat soils, but decreased 5%~45% in marsh soils and 20%~50% in peat soils with soil moistures increasing from non-inundation to inundation. The responses of CO2 production rate to temperatures were more sensitive in marsh soils than in peat soils, but the responses of CH4 production rate were similar. Temperatures played a more important role in CO2 production rate than soil moistures did, while soil moistures played a more important role in CH4 production rate. The Q10 values for CO2 production rate were higher at 5~25℃ than at 25~35℃, implying that carbon mineralization is more sensitive at low temperatures in Tibetan alpine wetlands.