Productivity-driven decoupling of microbial carbon use efficiency and respiration across global soils.
Where this comes from
- Record sourced from PubMed, PMID 41533799.
- Also identified by DOI 10.1126/sciadv.adz5319 and PMC identifier 12802823.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Despite extensive research on soil microbial carbon (C) use efficiency (CUE), its linkage to actual soil C storage remains ambiguous. A key uncertainty is that CUE estimates from short-term labeling incubations assume a linear negative relationship with respiration rates, overlooking nonlinear interactions and long-term microbial acclimation. Here, we use a stoichiometry-based approach to estimate CUE (CUE<sub>ST</sub>), which links soil resource availability to microbial demand and captures microbial adaptability under resource constraints. We synthesized 1094 paired observations of CUE<sub>ST</sub> and heterotrophic respiration rate (<i>R</i><sub>h</sub>) across natural ecosystems and found a nonlinear relationship between them governed by ecosystem productivity. In low-productivity arid and cold regions, CUE<sub>ST</sub> declined with increasing <i>R</i><sub>h</sub>, whereas in productive tropical and temperate regions, CUE<sub>ST</sub> stabilized at a low level (0.27 ± 0.11) as <i>R</i><sub>h</sub> exceeded 340 ± 10.8 grams of C per square meter per year. This shift reflects microbial trade-offs between C assimilation and stoichiometric homeostasis, revealing a decoupling of microbial growth from respiration that limits the capacity of productive ecosystems to store additional soil C.
Medical subject headings
- Soil Microbiology
- Carbon
- Soil