Thermal adaptation occurs in the respiration and growth of widely distributed bacteria

Soil microbial respiration is an important factor in regulating carbon (C) exchange between the soil and atmosphere. Thermal adaptation of soil microorganisms will lead to a weakening of the positive feedback between climate warming and soil respiration. The thermal adaptations of microbial communities and fungal species has been proven. However, studies on the thermal adaptation of bacterial species, the most important decomposers in the soil, are still lacking. Here, we isolated six species of widely distributed dominant bacteria and studied the effects of constant warming and temperature fluctuations on those species. The results showed that constant warming caused a downregulation of respiratory temperature sensitivity (Q10) of the bacterial species, accompanied by an elevation of the minimum temperature (Tmin) required for growth. Similar results were seen with the addition of temperature fluctuations, suggesting that both scenarios caused a significant thermal adaptation among the...