Understanding and prediction of soil microbial community dynamics under global change

The review deals with quantitative descriptions of soil microbial processes in northern terrestrial ecosystems and predictions of their possible modifications under anticipated global changes. The main focus is the dependence of population dynamics of soil microorganisms on environmental factors. To simulate microbial dynamics, mechanistic mathematical models are suggested which summarize the contemporary information on physiology and molecular biology of organisms representing different life strategies. The major independent environmental factors were clustered into three main groups: (i) soil mineral resources (available and deposited biogenic elements); (ii) factors related to solar radiation (sunlight, clouds, temperature, active layer, UVB); and (iii) factors affecting gas and liquid mass transfer (soil texture and porosity, vascular transfer, water regime). The quality and amount of organic matter which provide the sources of C and energy for most soil microorganisms are considered as dependent variables and can be generated by simulation models as a product of biosynthetic activity of plants and microorganisms. A strong interaction between different factors has been demonstrated, e.g. temperature and amount of available C nutrients which can be explained in physiological terms. The simulation of the tundra microbial community revealed its relatively high stability to global warming. Elevated temperatures and input of dead organic matter relieved the pressure of L-selection and accelerated an aerobic decomposition of dead organic matter (plant litter, soil humus). (C) 1999 Elsevier Science B.V.