Soil： An Extreme Habitat for Microorganisms？
摘要
The question is asked whether soils can be regarded as extreme environments with respect to microorganisms. After defining some extreme environments in a general sense, special properties of extreme environments are compared to soil habitats, with special emphasis laid on time frame and localities. In relation to water availability, nutrients and other properties, such places as aggregates can show properties of extreme habitats. These features, which can act at different levels of the system from the community level down to the cellular level, are summarized as stress factors. The latter,where many switches are located leading to different strategies of survival, is described as the most important one. This raises the question of how organisms have adapted to such conditions. The soil system demands a broad spectrum of adaptations and/or adjustments for a highly variable environment.The soil microorganisms'adaptation can thus be seen as the highest kind of flexibility and is more useful than any other special adaptation.