Linking heat and matter turnover over microbial successional stages in the soil to substrate quality and quantity

One of the major research foci of modern environmental sciences is the mechanism of carbon sequestration in the course of microbial decomposition of organic compounds in soil. Microorganisms decompose soil organic matter as a source of carbon, energy, and nutrients for their metabolism. The transformation process of various organic compounds in the soil is driven by competition between diverse microorganisms during several successional stages. The number, duration, and amplitude of which are dependent on substrate quality and quantity by regulating the tradeoff between fast but less efficient and slow but more efficient microbial taxa. In the frame of the Priority Program “Soil Systems”, funded by the German Research Foundation (DFG), we aim to study the relationships between substrate turnover rate, CO₂ release, heat production, and efficiency of microbial metabolism at various stages of microbial succession in the course of cellulose decomposition in a fertilized Haplic Cambisol soil. To link metabolism efficiency with microbial functional traits, the kinetic parameter of microbial enzymes and growth parameters are determined at different stages of microbial succession. This research will thus contribute to the elucidation of regulatory mechanisms of energy and matter turnover in soil.