Soil bacterial communities of loess-paleosol

A typical Luochuan section with an internationally recognized chronology was taken as the research object, and microbial communities of loess-paleosol were applied to investigate the evolutionary characteristics and indicative role of microorganisms in paleoclimate variations. Interglacial paleosols may reverse the trend of significantly declining soil nutrients and alpha diversity with increasing soil-forming time. Significant differences in bacterial community composition in loess and paleosol are mainly related to paleoclimate, especially precipitation and the winter monsoon. Additionally, glacial loess is mainly characterized by Actinobacteria and Firmicutes, while interglacial paleosol contains more Proteobacteria and Bacteroidetes, but this may also be affected by climate variety at millennia or smaller timescales. Besides, with the increase in soil formation time, bacterial interactome networks become simpler and tighter.