Nitrogen addition to soil affects microbial carbon use efficiency: Meta-analysis of similarities and differences in 13C and 18O approaches

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) 13C-labelled substrate addition (13C-substrate) and (ii) 18O-labelled water addition (18O-H2O). 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 13C-substrate approach, while CUE increased by 11% if measured by the 18O-H2O 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 13C incorporation into microbial biomass (this parameter is in the numerator by CUE calculation based on the 13C-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 18O-H2O 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 13C-substrate and 18O-H2O 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. © 2022 John Wiley & Sons Ltd.

Authors
Hu J. 1 , Huang C.1 , Zhou S.1 , Kuzyakov Y. 3, 4
Publisher
Blackwell Publishing Ltd
Language
English
Status
Published
Year
2022
Organizations
  • 1 College of Forestry, Sichuan Agricultural University, Chengdu, China
  • 2 National Forestry and Grassland Administration Key Laboratory of Forest Resources Conservation and Ecological Safety on the Upper Reaches of the Yangtze River, College of Forestry, Sichuan Agricultural University, Chengdu, China
  • 3 Department of Soil Science of Temperate Ecosystems, Department of Agricultural Soil Science, University of Goettingen, Göttingen, Germany
  • 4 Peoples Friendship University of Russia (RUDN University), Moscow, Russian Federation
Keywords
approach comparison; carbon mineralization; global change; microbial growth; microbial respiration; nutrient addition
Date of creation
06.07.2022
Date of change
06.07.2022
Short link
https://repository.rudn.ru/en/records/article/record/84024/
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