| In order to understand the balance of methane in soils from the typical area across China and its response to temperature,we studied methane oxidation of typical frozen soil and farmland soil（from eastern China）with high concentration of methane at normal temperature（25℃）and at different temperature（5℃,15℃,25℃,35℃）.Beside,we studied the anaerobic production of methane from the main methane production soil（rice paddy soil and wetlands）at different temperature as set above.Meanwhile the organic geochemistry methods PLFA and GDGTs analysis were applied to elucidate the mechanism of soil methane oxidation and soil methane production respectively in this study.At normal temperature,65%of the total farm soil samples could oxidize the high concentrations of methane,while only 29%of the frozen soil samples could significantly oxidize the high content of methane.Soil methane oxidation was different between samples.The study of methane oxidation at different temperature showed that only alpine steppe soil from Qinghai didn’t have the potential for methane oxidation at the four temperatures.While Heilongjiang coniferous forest soil（DZS1）,Jilin dark brown soil（HYB09）,Hebei fluvo-aquic soil（HYC01）,Anhui rice soil（HYE19）and Jiangxi rice soil（HYF01）had the ability to oxidize methane with the optimum temperature at 25℃,25-35℃,35℃,25-35℃ and 35 respectively.The maximum potential of oxidation of methane from the four temperatures of these samples was Jiangxi rice soil>Hebei fluvo-aquic soil>Anhui rice soil>Jilin dark brown soil>Heilongjiang coniferous forest soil.From PLFA analysis,type I of methane oxidizing bacteria（MOB）were dominant in the surface soil samples.with rising temperature,the community of MOB from alpine grassland soil from Qinghai changed with a little bit,while the density of type Ⅰ MOB from Jiangxi and Anhui decreased and type Ⅱ MOB increased,the remaining samples appeared the reverse phenomena with type Ⅰ MOB increased and type Ⅱ MOB decreased.We conclude that rising temperatures,as predicted for the future,seem to increase the importance of type Ⅱmethanotrophs,which may affect methane cycling in Heilongjiang coniferous forest soil,Anhui rice soil and Jiangxi rice soil.From the anaerobic production of methane at different temperatures,the production of methane showed a positive relation to temperature,rice paddy soil and wetlands soil had the maximum methane production at 35℃ and 25℃ respectively.The potential of methane production of these samples was Heilongjiang wetlands peat soil（DZZ1）>Jiangxi rice paddy soil（JXSDT）>Qinghai meadows swamp land（XZTTH01）>Anhui rice paddy soil（AHSDT）>Heilongjiang swamp wetland soil（ZZT）.The GDGTs analysis for these samples showed that the abundance of methanogen archaea from GDGTs analysis is positive to the production of methane.Overall,rising concentration of methanogen result in increasing of methane production with rising temperature. |
