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选择甘肃西峰和陕西段家坡两个黄土剖面，采取磁化率变化显著的Ｌ_６－Ｓ_５－Ｌ_５层段，在８～１８℃室温、２５，２６和３０℃左右等多种条件下富集培养趋磁细菌（ＭＢ），通过透射电子显微镜（ＴＥＭ）观察各样品中ＭＢ，的多少、大小、形态，以及其中磁小体（ＭＳ）的特征．总的来说，ＭＢ广泛存在于黄土－古土壤序列之中，古土壤中ＭＢ及其细胞内的ＭＳ相对较多，菌体形态亦较多，有杆状菌、弧形菌等；其中的ＭＳ基本呈链状沿细胞长轴排列．其次，黄土剖面中趋磁细菌的分布与古气候环境存在一定的关系．从黄土剖面中ＭＢ和ＭＳ的分布可推测：在整个黄土－古土壤序列形成时期，黄土高原地区古气候一直处于频繁波动状态，由西北而东南，气候呈逐渐变暖趋势，波动也更趋频繁
The two loess sections, Xifeng, Gansu and Duanjiapo, Shaanxi, were selected and the L_6-S_5-L_5 layer with significant changes of magnetic susceptibility was selected to enrich the culture trend under the conditions of 8-18 ℃ room temperature, 25, 26 and 30 ℃, Magnetobacteria (MB) were used to observe the number, size, morphology, and the characteristics of magnetosomes (MS) in each sample by transmission electron microscopy (TEM). In general, MB is widely found in the loess-paleosol sequence, and there are relatively more MBs and intracellular MSs in ancient soils, with more cell morphology, such as bacilli and arc bacteria MS basically arranged along the long axis of the cell chain. Second, the distribution of magnetotactic bacteria in the loess profile has a certain relationship with paleoclimate environment. From the distribution of MB and MS in the loess section, it can be inferred that the palaeoclimate of the Loess Plateau has been in a state of frequent fluctuations throughout the formation of the Loess-Paleosol sequence, with a gradual warming trend and a more frequent fluctuation from northwest to southeast