中文摘要：

冻融作用通过破坏土壤结构、影响土壤水分有效性和土壤团聚体稳定性,影响土壤中微生物的活性和有机质分解二氧化碳的排放。采用室内培养试验,在两个温度梯度（10℃和20℃）下,分析在不同冻融作用处理下大兴安岭多年冻土湿地泥炭分解排放二氧化碳的特征。总的泥炭分解二氧化碳的排放量变化范围为27.27～85.50 mg g^-1。结果表明,虽然温度仍是决定泥炭分解二氧化碳排放的关键因子,但随着冻融循环处理次数的增加,泥炭分解排放的二氧化碳量降低,冻融作用对泥炭分解二氧化碳的排放有一定的抑制作用。并且冻融作用存在着＂激发效应＂,可刺激冻融处理第一天的泥炭分解二氧化碳的排放。通过回归方程很好地反映了泥炭分解二氧化碳排放的动态变化（P〈0.001）,经过冻融作用处理的泥炭与未经过冻融作用处理的泥炭分解二氧化碳的排放率变化趋势一致,在短期内,冻融作用不会加快泥炭的分解和二氧化碳的排放。

英文摘要：

Freezing and thawing significantly affected soil structure,the availability of soil water,stability of aggregates,the activity of the microbe and soil carbon decomposition.This study was aimed to understand the characteristics in the CO2 emission of peat C decomposition by freezing and thawing cycles on the permafrost wetland in the Great Hing＇an mountains,which was incubated under different freezing and thawing cycle regimes.The total carbon mineralization ranged from 27.27 to 85.50 mg g^-1.Although temperature plays a crucial role in determining the carbon mineralization,the results showed that the peat C decomposition was decreasing with the freezing and thawing cycles increasing during the incubation time.There was ＂Priming Effects＂ on the first day of the incubation time and it led to increased CO2 emission.We successfully predicted the carbon decomposition as a regression function of icubation time（P0.001）.There were similarly trend of the peat carbon mineralization rates between peat under the treatments and peat without freezing-thaw cycles treatments.In short phases,the freezing-thawing cycles would not accelerate the peat carbon decomposition.