Diversity and succession of chemolithoautotrophic microbial community along a recently deglaciation chronosequence on the Tibetan Plateau

Abstract

Chemolithoautotrophic microbes colonize deglaciated soils quickly and follow a clear successional pattern across recently deglaciated chronosequences. Glaciers in high-altitude mountain regions are retreating rapidly due to global warming, exposing deglaciated soils to extreme environmental conditions, and microbial colonization. However, knowledge about chemolithoautotrophic microbes, which play important roles in the development of oligotrophic deglaciated soils prior to plant colonization, remains elusive in deglaciated soils. Using real-time quantitative PCR and clone library methods, the diversity and succession of the chemolithoautotrophic microbial community harboring the cbbM gene across a 14-year deglaciation chronosequence on the Tibetan Plateau were determined. The abundance of the cbbM gene remained stable for the first 8 years after deglaciation and then increased significantly, ranging from 10(5) to 10(7) gene copies g(-1) soil (P < 0.001). Soil total carbon increased gradually to 5-year deglaciation and then decreased. While total nitrogen and total sulfur levels were low throughout the chronosequence. Chemolithoautotrophs were related to Gammaproteobacteria and Betaproteobacteria, with the former dominating early deglaciated soils and the latter dominating older deglaciated soils. The diversity of chemolithoautotrophs was high in mid-age deglaciated soils (6-year-old) and was low in early (3-year-old) and older deglaciated soils (12-year-old). Our findings revealed that chemolithoautotrophic microbes colonize deglaciated soils quickly and follow a clear successional pattern across recently deglaciated chronosequences.