A THEORETICAL MODEL OF LITTER DECAY AND MICROBIAL INTERACTION

Abstract

Despite the central role of microorganisms in the decomposition of dead organic matter, few models have integrated the dynamics of litter chemistry with microbial interactions. Here we propose a functional resolution of the microbial community that parallels the commonly used chemical characterization of plant litter, i.e., a guild of opportunist microorganisms that grows quickly and has high affinity for soluble substrates, a guild of decomposer specialists that grows more slowly and has high affinity for holocellulose substrates, and a guild of miners that grows very slowly and is specialized for degrading lignin. This guild-based decomposition model (GDM) includes the interactions of holocellulose and lignin, manifest as mutual feedback controls on microbial-based activities. It also includes N limitations on early stages of litter decay resulting from nutritional demands of microorganisms and N inhibition on late stages of litter decay resulting from reduced lignin degradation. Competitive interaction...