中文摘要：

运用HPLC-APCI-MS详细分析了青藏高原东部红原现代泥炭（32°46′N，102°31′E）和越西现代泥炭（28°46′N，102°34′E）中甘油二烷基甘油四醚类脂物（glycerol dialkyl glycerol tetraethers，简称GDGTs）的组成及分布特征，检测出了丰富的GDGTs化合物，显示研究区分布着产甲烷菌、氨氧化古菌、细菌等多种微生物。其中，细菌支链GDGTs（branchedGDGTs，简称bGDGTs）丰度明显高于占菌类异戊二烯GDGTs（isoprenoidGDGTs，简称iGDGTs）。无环的GDGT-0和archaeol是古菌iGDGTs的主要组分，说明古菌以产甲烷菌为主。bGDGTs中Ia与IIa中度最高，由CBT（环化指数）参数得到的pH值与泥炭实测pH值相近，但基于MBT（甲基化指数）-CBT指标得到的年平均大气温度（MAT）与两研究区现代年平均温度有一定差别。通过该项工作发现今后进行区域细菌bGDGTs相关环境参数的校正是十分必要的。

英文摘要：

In our study, the samples were collected from 2 modern peat sediments, namely Hongyuan region （32°46′N, 102°31′E; 3508m a.s.l.） and Yuexi region （28°46′N, 102°34′E; 1981m a.s.l.） in the eastern Tibetan Plateau. The glycerol dialkyl glycerol tetraethers （GDGTs） in all samples were analyzed by high performance liquid chromatography-atmospheric pressure chemical ionization-mass spectrometry （HPLC-APCI-MS）. Our results have shown that microbial assemblages are abundant in the Tibetan peats, including methanogens, ammonia-oxidising Thaumarchaeota and likely anaerobic bacteria based on distributions of branched and isoprenoidal GDGTs. Branched GDGTs （bGDGTs） are much more abundant than the isoprenoid GDGTs （iGDGTs）. GDGT-0 and archaeol are predominant in all peat samples, indicating that methanogens are the major archaea. The branched GDGTs are dominated by bGDGT Ia and IIa. The cyclization of bGDGTs （ CBT）-derived pH values are closed to the measured peat pH in the study regions. However, the mean annual air temperature （MAT） estimates derived from the methylation of bGDGTs and cyelization of bGDGTs （MBT＇-CBT） are different from the present mean annual temperature of the study regions. MBT＇-CBT-derived MAT values are higher than present mean annual temperature in Hongyuan region and lower than that in Yuexi region. Taken together, the global soil calibration of （Peterse et al., 2012）[31] appears not to be applicable to MAT estimates in Tibetan peats. Therefore, we suggest that it is necessary to calibrate the MBT＇-CBT index of bGDGTs in peat settings.