Microorganisms and Soil-Ecosystem Development: Do Soil Microbial Communities Show Patterns of Succesion?.

Stemming from its ability to provide order and predictability in very complex ecosystems, succession has survived nearly a century as a paradigm in ecosystem ecology. Soils and their microorganisms have long been considered key to ecosystem function, but the changing composition of microbial communities have not been adequately studied in the context of ecosystem development. To gain a better understanding of how bacterial communities change during soil ecosystem development, we studied their composition and diversity in soils that developed over ~77,000 years of intermittent eolian deposition.16S rRNA gene clone libraries were used to assess the diversity and composition of the communities. The bacterial community composition changed with soil age, and the overall diversity, richness and evenness of the communities increased as the soil habitat matured. Bray-Curtis ordination suggested an orderly pattern of change of the bacterial community associated with the depositional age of the soil. While the bacterial communities along the chronosequence were relatively rich, the plant diversity was low and changed in a pattern that appeared to be unrelated to changes in the bacterial communities. Microbial community change along the chronosequence, nevertheless, was reminiscent of successional processes often evoked to describe plant community change during the development of in terrestrial ecosystems.