Nitrogen addition to soil affects microbial carbon use efficiency: Meta-analysis of similarities and differences in 13 C and 18 O approaches.
Glob Chang Biol
; 28(16): 4977-4988, 2022 08.
Article
em En
| MEDLINE
| ID: mdl-35617026
ABSTRACT
The carbon use efficiency (CUE) of soil microorganisms is a critical parameter for the first step of organic carbon (C) transformation by and incorporation into microbial biomass and shapes C cycling in terrestrial ecosystems. As C and nitrogen (N) cycles interact closely and N availability affects microbial metabolism, N addition to soil may shift the microbial CUE. We conducted a meta-analysis (100 data pairs) to generalize information about the microbial CUE response to N addition in soil based on the two most common CUE estimation approaches (i) 13 C-labelled substrate addition (13 C-substrate) and (ii) 18 O-labelled water addition (18 O-H2 O). The mean microbial CUE in soils across all biomes and approaches was 0.37. The effects of N addition on CUE, however, were depended on the approach:
CUE decreased by 12% if measured by the 13 C-substrate approach, while CUE increased by 11% if measured by the 18 O-H2 O approach. These differences in the microbial CUE response depending on the estimation approach are explained by the divergent reactions of microbial growth to N addition N addition decreases the 13 C incorporation into microbial biomass (this parameter is in the numerator by CUE calculation based on the 13 C-substrate approach). In contrast, N addition slightly increases (although statistically insignificant) the microbial growth rate (in the numerator of the CUE calculation when assessed by the 18 O-H2 O approach), significantly raising the CUE. We explained these N addition effects based on CUE regulation mechanisms at the metabolic, cell, community, and ecosystem levels. Consequently, the differences in the microbial responses (microbial growth, respiration, C incorporation, community composition, and dormant or active states) between the 13 C-substrate and 18 O-H2 O approaches need to be considered. Thus, these two CUE estimation approaches should be compared to understand microbially mediated C and nutrient dynamics under increasing anthropogenic N input and other global change effects.Palavras-chave
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Base de dados:
MEDLINE
Assunto principal:
Solo
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Carbono
Tipo de estudo:
Systematic_reviews
Idioma:
En
Revista:
Glob Chang Biol
Ano de publicação:
2022
Tipo de documento:
Article
País de afiliação:
China