Compensatory Thermal Adaptation of Soil Microbial Respiration Rates in Global Croplands

Jian Sheng Ye*, Mark A. Bradford, Fernando T. Maestre, Feng Min Li*, Pablo García-Palacios

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

11 Scopus citations

Abstract

Understanding whether soil microbial respiration adapts to the ambient thermal climate with an enhanced or compensatory response, hence potentially stimulating or slowing down soil carbon losses with warming, is key to accurately forecast and model climate change impacts on the global carbon cycle. Despite the interest in this topic and the plethora of recent studies in natural ecosystems, it has been seldom explored in croplands. Using two recently published independent datasets of soil microbial metabolic quotient (MMQ; microbial respiration rate per unit biomass) and carbon use efficiency (CUE; partitioning of C to microbial growth vs. respiration), we find a compensatory thermal adaptive response for MMQ in global croplands. That is, mean annual temperature (MAT) has a negative effect on MMQ. However, this compensatory thermal adaptation is only half or less of that found in previous studies for noncultivated ecosystems. In contrast to the negative MMQ-MAT pattern, microbial CUE increases with MAT across global croplands. By incorporating this positive CUE-MAT relationship (greater C partitioning into microbial growth rather than respiration with increasing temperature) into a microbial-explicit soil organic carbon model, we successfully predict the thermal compensation of MMQ observed in croplands. Our model-data integration and database cross-validation suggest that a warmer climate may select for microbial communities with higher CUE, providing a plausible mechanism for their compensatory metabolic response. By helping to identify appropriate representations of microbial physiological processes in soil biogeochemical models, our work will help build confidence in model projections of cropland C dynamics under a changing climate.

Original languageEnglish (US)
Article numbere2019GB006507
JournalGlobal Biogeochemical Cycles
Volume34
Issue number6
DOIs
StatePublished - Jun 1 2020

Keywords

  • agriculture
  • ecological stoichiometry
  • global warming
  • heterotrophic respiration
  • mass specific respiration
  • microbial carbon use efficiency

ASJC Scopus subject areas

  • Global and Planetary Change
  • Environmental Chemistry
  • General Environmental Science
  • Atmospheric Science

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