Microbial Carbon Use Efficiency in Coastal Soils Along a Salinity Gradient Revealed by Ecoenzymatic Stoichiometry

• Published in: Journal of geophysical research. Biogeosciences 2022-08, Vol.127 (8), p.n/a
• Main Authors: Dong, Y., Chen, R. R., Petropoulos, E., Yao, T. Y., Yu, B. Q., Lin, X. G., Feng, Y. Z.
• Format: Article
• Language: English
• Subjects: Abiotic stress; Adaptation; Atmosphere; Carbon; carbon constraint; Carbon cycle; Carbon/nitrogen ratio; Correlation; ecoenzymatic stoichiometry; Efficiency; Electrical resistivity; Gas exchange; Growth rate; microbial carbon use efficiency; Microorganisms; saline soils; Salinity; Salinity effects; Salinity gradients; salinity threshold; Salt; Salts; Soil; Soil salinity; Soils; Stoichiometry; Survival
• ISSN: 2169-8953; 2169-8961
• DOI: 10.1029/2022JG006800

Soil salinity affects the microbial carbon use efficiency (CUE) that in turn regulates soil‐atmosphere gas exchange and soil C sequestration. So far, little is known about CUE in salt‐affected soils. Hereby, CUE across coastal soils with electric conductivity (EC) ranging from 0.14 dS m−1 to 13.65 dS m−1 was investigated using stoichiometric modeling. Contrary to the belief that CUE decreases with salinity increase, this present study showed that CUE follows a unimodal pattern along the saline gradient with the highest CUE observed at EC = 2 dS m−1. When EC > 2 dS m−1, both CUE and soil microbial growth rate significantly decrease with salinity indicating that microorganisms sacrifice growth for survival/adaptation to high salt stress. When EC  2 dS m−1, both CUE and soil microbial growth rate significantly decrease with salinity indicating that microorganisms sacrifice growth for survival/adaptation to high salt stress. When EC