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Apparent thermal acclimation of soil heterotrophic respiration mainly mediated by substrate availability

Citation

He, Yanghui et al. (2022), Apparent thermal acclimation of soil heterotrophic respiration mainly mediated by substrate availability, Dryad, Dataset, https://doi.org/10.5061/dryad.70rxwdc2d

Abstract

Multiple lines of existing evidence suggest that increasing CO2 emission from soils in response to rising temperatures could accelerate global warming. However, in experimental studies, the initial positive response of soil heterotrophic respiration (RH) to warming often weakens over time (referred to apparent thermal acclimation). If the decreased RH is driven by the thermal adaptation of soil microbial community, the potential for soil carbon (C) losses would be reduced substantially. In the meanwhile, the response could equally be caused by substrate depletion, and would then reflect the gradual loss of soil C. To address uncertainties regarding the causes of apparent thermal acclimation, we carried out sterilization and inoculation experiments using the soil samples from an alpine meadow with 6-years of warming and nitrogen (N) addition. We demonstrate that substrate depletion, rather than microbial adaptation, determined the response of RH to long-term warming. Furthermore, N addition appeared to alleviate the apparent acclimation of RH to warming. Our study provides strong empirical support for substrate availability being the cause of the apparent acclimation of soil microbial respiration to temperature. Thus, these mechanistic insights could facilitate efforts of biogeochemical modeling to accurately project soil C stocks in the future climate.

Funding

National Natural Science Foundation of China, Award: 31901200

Shanghai Sailing Program, Award: 19YF1413300

Fundamental Research Funds for the Central Universities, Award: 2572022BA04

National Natural Science Foundation of China, Award: 32271713

National Natural Science Foundation of China, Award: 31930072