The application of ecological stoichiometry to plant–microbial–soil organic matter transformations

TLDR

Elemental stoichiometry links biogeochemistry to food‑web structure and processes, spanning from cellular metabolism to ecosystem‑scale nutrient cycling, and is central to ecosystem functioning, yet while plant, litter, and soil stoichiometry are well understood, heterotrophic microbial communities are increasingly recognized for their role in nutrient cycling. The authors review C:N:P ratios across terrestrial ecosystem components—from vegetation and litter to soil microbes and organic matter—to examine how resource stoichiometry shapes heterotrophic microbial community structure and decomposition. They synthesize literature to propose general patterns linking stoichiometry to microbial community dynamics and decomposition processes. The authors report that soil and litter stoichiometry gradients influence microbial community structure and function, that stoichiometric shifts alter microbial interactions and nutrient feedbacks, and that global change modifies primary producer C:N:P ratios, thereby affecting decomposer communities and soil fertility, illustrating that ecological stoichiometry can predict such global‑change effects.

Abstract

Elemental stoichiometry constitutes an inherent link between biogeochemistry and the structure and processes within food webs, and thus is at the core of ecosystem functioning. Stoichiometry allows for spanning different levels of biological organization, from cellular metabolism to ecosystem structure and nutrient cycling, and is therefore particularly useful for establishing links between different ecosystem compartments. We review elemental carbon : nitrogen : phosphorus (C:N:P) ratios in terrestrial ecosystems (from vegetation, leaf litter, woody debris, and dead roots, to soil microbes and organic matter). While the stoichiometry of the plant, litter, and soil compartments of ecosystems is well understood, heterotrophic microbial communities, which dominate the soil food web and drive nutrient cycling, have received increasing interest in recent years. This review highlights the effects of resource stoichiometry on soil microorganisms and decomposition, specifically on the structure and function of heterotrophic microbial communities and suggests several general patterns. First, latitudinal gradients of soil and litter stoichiometry are reflected in microbial community structure and function. Second, resource stoichiometry may cause changes in microbial interactions and community dynamics that lead to feedbacks in nutrient availability. Third, global change alters the C:N, C:P, and N:P ratios of primary producers, with repercussions for microbial decomposer communities and critical ecosystem services such as soil fertility. We argue that ecological stoichiometry provides a framework to analyze and predict such global change effects at various scales.