【目的】探究直接种间电子转移(direct interspecies electron transfer,DIET)机制在增温下青藏高原若尔盖泥炭地甲烷排放中的作用,探索全球变暖背景下基于DIET机制的甲烷减排措施。【方法】以若尔盖泥炭地3种优势植物根部土壤为研究对...【目的】探究直接种间电子转移(direct interspecies electron transfer,DIET)机制在增温下青藏高原若尔盖泥炭地甲烷排放中的作用,探索全球变暖背景下基于DIET机制的甲烷减排措施。【方法】以若尔盖泥炭地3种优势植物根部土壤为研究对象,构建室内土壤果胶和纤维素厌氧富集物(18℃),通过添加电子传输介质——生物炭及电化学实验,探究直接种间电子转移对植物有机碳来源产甲烷过程的作用及增温(28℃)对甲烷产生的效果。【结果】添加生物炭提高了18℃培养物从纤维素和果胶来源的甲烷产量1.1-9.8倍,提高了产甲烷速率1.4-12.3倍;添加生物炭后温度敏感性提高了2倍。计时电流法检测到电化学培养物中从细菌产生的胞外电子,其电流密度为33.7μA/cm^(2),及产甲烷古菌介导的电流消耗(21.2μA/cm^(2))。16S rRNA基因多样性分析发现,生物炭添加显著富集了已知的电活性细菌——地杆菌科(Geobacteraceae)和产甲烷古菌——甲烷八叠球菌科(Methanosarcinaceae)、嗜甲基甲烷菌科(Methanomethylophilaceae)及未培养的产甲烷古菌类群Rice ClusterⅡ。泥炭地中的Geobacteraceae和纤维素单胞菌科(Cellulomonadaceae)均与Rice ClusterⅡ具有显著共现性,推测它们可能通过直接种间电子转移介导植物有机碳产甲烷的过程。【结论】直接种间电子转移机制在若尔盖泥炭地植物有机碳产甲烷过程中发挥重要作用,尤其在增温下该作用更显著。因此抑制种间电子转移是泥炭地甲烷减排的措施之一。展开更多
In this study,the climate trend of the annual average air temperature and total annual rainfall in China in the present century has been examined.It is noted that in the Northwest,the Northeast and North China the cli...In this study,the climate trend of the annual average air temperature and total annual rainfall in China in the present century has been examined.It is noted that in the Northwest,the Northeast and North China the climate has become notably warmer this century but the rainfall trend has not been evident,mainly negative.In the 1980s China's rainfall and temperature showed noticeable regional features: warm and dry in North China,cold and dry in the Southwest,warm and wet in the Northeast,cold and wet in the middle-lower reaches of the Changjiang River.Besides,the four interdecadal climate change features and ranges of this century have been studied.It is found that on the scale of several decades there was considerably less rainfall in the most part of China in the warm background than in the cold background.The increase of temperature which started from the 1970s mainly happened in the Northwest and Northeast,while to the south of the Huanghe River the temperature increase did not even as great as in 1940s.The corresponding rainfall feature is that most areas experienced much less rainfall except the area to the south of the Huanghe River and over the Changjiang and Huaihe River basin.展开更多
基金This research was supported by the National Natural Science Foundation of China (No: 49475265).
文摘In this study,the climate trend of the annual average air temperature and total annual rainfall in China in the present century has been examined.It is noted that in the Northwest,the Northeast and North China the climate has become notably warmer this century but the rainfall trend has not been evident,mainly negative.In the 1980s China's rainfall and temperature showed noticeable regional features: warm and dry in North China,cold and dry in the Southwest,warm and wet in the Northeast,cold and wet in the middle-lower reaches of the Changjiang River.Besides,the four interdecadal climate change features and ranges of this century have been studied.It is found that on the scale of several decades there was considerably less rainfall in the most part of China in the warm background than in the cold background.The increase of temperature which started from the 1970s mainly happened in the Northwest and Northeast,while to the south of the Huanghe River the temperature increase did not even as great as in 1940s.The corresponding rainfall feature is that most areas experienced much less rainfall except the area to the south of the Huanghe River and over the Changjiang and Huaihe River basin.
