Antibiotic legacies shape the temperature response of soil microbial communities

Soil microbial communities are vulnerable to global change factors and land management decisions; these factors can therefore affect microbially-mediated ecosystem functions. Increasingly, multiple stressors are considered in investigations of ecological response to disturbances. Here, we investigate how historical exposure to antibiotics affects the soil microbial response to a subsequent temperature change. In-situ antibiotic exposure initially increased soil respiration; however, this effect diminished over time. A subsequent incubation experiment showed that historical antibiotic exposure caused an acclimation-like response to increasing temperature. This response was likely driven by a differential response in the microbial community of antibiotic-exposed soils. Microbial communities exposed to antibiotics tended to be dominated by slower-growing, oligotrophic taxa at higher temperatures. Therefore, historical exposure to one stressor is likely to influence the microbial community to subsequent stressors. To predict the response of soils to future stress, particularly increasing soil temperatures, historical context is necessary.