Antibiotics and temperature interact to disrupt soil communities and nutrient cycling

Soils contain immense diversity and support terrestrial ecosystem functions, but they face numerous anthropogenic pressures. Understanding how soils will respond to multiple stressors is critical for maintaining biodiversity and function. Here, we examined how introductions of low and high doses of the livestock antibiotic Monensin shape soil communities, and how these effects are mediated by soil temperature. We found that antibiotics and rising soil temperatures interacted to disrupt bacterial communities and connectivity, allowing for a rise in fungal dominance and change in soil nutrient stoichiometry. Independent of temperature, antibiotics decreased bacterial diversity, abundance, total extractable N and microbial efficiency, while increasing bioavailable C. Higher temperatures independently homogenized fungal community composition, decreased dissolved organic C and increased soil respiration rates. These results emphasize that as soils encounter multiple stressors, ecosystem efficiency, stability and resilience may be diminished.