中文摘要：

在全球变暖的背景下,内蒙古草地吸收甲烷的功能也会随之发生变化,而甲烷氧化菌的氧化能力是影响吸收甲烷的重要因素.选择内蒙古锡林河流域附近的典型草地,研究不同围封年限甲烷氧化菌的氧化能力及对不同温度梯度的响应.3个样地分别为从1979年开始围封的草地（79E）、从1999年开始围封的草地（99E）和自由放牧草地（G）.通过不同温度条件下室内培养获得3个样地甲烷氧化菌的氧化活性并且计算出3个样地甲烷氧化菌活性对温度的敏感性（Q10）.结果显示：18℃时3个样地甲烷氧化菌的活性分别是0.032、0.012、0.024μg g^-1 h^-1;28℃时3个样地甲烷氧化菌的活性分别是0.042、0.031、0.055μg g^-1 h^-1.79E的Q10值最低,99E的Q_（10）值最低.在3个样地中,温度越高,甲烷氧化菌的氧化活性越强.通过对甲烷氧化菌氧化潜能的计算以及和原位通量数据的比较可以看出,甲烷氧化菌的氧化潜能显著高于原位通量数据,说明在未来全球变暖的情况下,草地作为大气甲烷汇的功能也会增强.

英文摘要：

This study aimed to investigate the methanotrophic activity and its response to global warming with different enclosure time.We chose typical grasslands in Xilin River Basin of Inner Mongolia,China to investigate the methanotrophic activity at 18 ℃ and 28 ℃ under different enclosure treatments：79E（grassland enclosed since 1979）,99E（grassland enclosed since 1999） and G（freely-grazed grassland）.The main methods included laboratory incubation experiment and the collection of CH4 flux data.The results showed that at 18 ℃,the methanotrophic activity was 0.032 μg g^-1 h^-1 for 79 E,0.012 μg g^-1 h^-1 for99 E,and 0.024 μg g^-1 h^-1 for G.At 28℃,the methanotrophic activity was 0.042 μg g^-1h^-1,0.031 μg g^-1 h^-1 and 0.055 μg g^-1 h^-1,respectively.The methanotrophic activity of 79 E was found to have the lowest sensitivity to temperature change,while 99 E had the highest one.The methanotrophic activity in all three treatments increased along with the temperature.Taking into account the methanotrophs potential and comparing the in situ CH4 fluxes,we concluded that grassland can remove more CH4 under the future global warming trend.