Title
Stoichiometric imbalances between terrestrial decomposer communities and their resources: mechanisms and implications of microbial adaptations to their resources
Author
Maria Mooshammer
Author
Wolfgang Wanek
Author
Sophie Zechmeister-Boltenstern
Institute of Soil Research, Department of Forest and Soil Sciences, University of Natural Resources and Life Sciences Vienna
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Abstract
Terrestrial microbial decomposer communities thrive on a wide range of organic matter types that rarely ever meet their elemental demands. In this review we synthesize the current state-of-the-art of microbial adaptations to resource stoichiometry, in order to gain a deeper understanding of the interactions between heterotrophic microbial communities and their chemical environment. The stoichiometric imbalance between microbial communities and their organic substrates generally decreases from wood to leaf litter and further to topsoil and subsoil organic matter. Microbial communities can respond to these imbalances in four ways: first, they adapt their biomass composition toward their resource in a non-homeostatic behavior. Such changes are, however, only moderate, and occur mainly because of changes in microbial community structure and less so due to cellular storage of elements in excess. Second, microbial communities can mobilize resources that meet their elemental demand by producing specific extracellular enzymes, which, in turn, is restricted by the C and N requirement for enzyme production itself. Third, microbes can regulate their element use efficiencies (ratio of element invested in growth over total element uptake), such that they release elements in excess depending on their demand (e.g., respiration and N mineralization). Fourth, diazotrophic bacteria and saprotrophic fungi may trigger the input of external N and P to decomposer communities. Theoretical considerations show that adjustments in element use efficiencies may be the most important mechanism by which microbes regulate their biomass stoichiometry. This review summarizes different views on how microbes cope with imbalanced supply of C, N and P, thereby providing a framework for integrating and linking microbial adaptation to resource imbalances to ecosystem scale fluxes across scales and ecosystems.
Keywords
Ecological stoichiometryhomeostasiscarbon/nutrient use efficiencyelemental imbalancesoil microbial communitiesextracellular enzymesmineralizationorganic matter decomposition
Object type
Language
English [eng]
Persistent identifier
https://phaidra.univie.ac.at/o:467113
Appeared in
Title
Frontiers in Microbiology
Volume
5
Publisher
Frontiers Media SA
Date issued
2014
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