Aeration and mineral composition of soil mediate microbial CUE

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F60077344%3A_____%2F25%3A00640608" target="_blank" >RIV/60077344:_____/25:00640608 - isvavai.cz</a>

Alternative codes found

RIV/60076658:12310/25:43910527 RIV/60461373:22330/25:43932498

Result on the web

<a href="https://soil.copernicus.org/articles/11/735/2025/soil-11-735-2025.pdf" target="_blank" >https://soil.copernicus.org/articles/11/735/2025/soil-11-735-2025.pdf</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.5194/soil-11-735-2025" target="_blank" >10.5194/soil-11-735-2025</a>

Result language

angličtina

Original language name

Aeration and mineral composition of soil mediate microbial CUE

Original language description

In ecosystem studies, microbial carbon use efficiency (CUE) is often used to estimate the proportion of organic substrate (glucose) consumed by microbial biomass that is not released from soil as CO2. While most studies assume aerobic conditions, with CO2 and microbial biomass as the predominant products of organic substrate processing, anoxic microniches are common inside soil aggregates. Microorganisms in these microniches perform fermentation and anaerobic respiration using alternative electron acceptors: processes connected with the release of extracellular intermediates. These extracellular intermediates and other compounds are not traditionally accounted for but may represent a significant C flux when compared to microbial biomass formation. Climate change may modulate soil microbial activity by altering soil aeration status on a local level. Therefore, CUE as an intrinsic parameter that is used in ecosystem studies and modelling should be defined for more realistic assumptions regarding soil aeration.This study focused on the effect of oxygen and Fe availability on C mineralisation in forest soils and quantified C distribution between biomass and different extracellular metabolites. Forest soils from two Bohemian Forest (Czechia) sites, with low and high Fe content, were incubated under oxic and anoxic conditions. A solution of 13C-labelled glucose was used to track C incorporation into the biomass, respired CO2, and extracellular metabolites. We estimated CUE based on measured cumulative microbial respiration, residual glucose, biomass, and extracellular metabolites concentration. RNA-SIP was used to identify the active bacteria under each treatment. Under oxic conditions, glucose was rapidly consumed and largely converted to CO2, with greater microbial biomass and CUE observed in the low-Fe soil compared to the high-Fe soil. In contrast, under anoxic conditions, glucose consumption was slower, leading to the accumulation of fermentation products, especially in the high-Fe soil, and higher carbon storage efficiency. Microbial growth and turnover were generally lower under anoxic conditions. A large and diverse portion of the microbial community rapidly incorporated 13C-labelled glucose under oxic conditions, with over 300 active amplicon sequence variants (ASVs) identified primarily from dominant phyla like Proteobacteria, Actinomycetota, and Bacteroidota. In contrast, anoxic conditions led to much slower and more limited labelling, with only a few ASVs (mainly Firmicutes) incorporating 13C. Our findings confirm that anoxia in soils enhances short-term C preservation and suggest that excluding exudates in mass flux calculations would underestimate C retention in the soil, especially under anoxic conditions.

Czech name

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Czech description

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Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

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OECD FORD branch

40104 - Soil science

Project

Result was created during the realization of more than one project. More information in the Projects tab.

Continuities

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2025

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Soil

ISSN

2199-3971

e-ISSN

2199-398X

Volume of the periodical

11

Issue of the periodical within the volume

2

Country of publishing house

DE - GERMANY

Number of pages

19

Pages from-to

735-753

UT code for WoS article

001584806500001

EID of the result in the Scopus database

2-s2.0-105017810804