Effects of contrasting precipitation patterns on the trajectory of actively growing and inactive microbial communities after rewetting

Abstract

Predicted shifts in precipitation patterns could impact soil microbial activity, and thereby terrestrial ecosystem functioning. In a Mediterranean grassland soil which had been subjected to contrasting precipitation patterns, we investigated the response of active and inactive bacterial and fungal communities to rewetting over time, using 18O stable isotope probing. Altered precipitation patterns prior to rewetting had little impact on the trajectories over time of the active and inactive bacterial communities after rewetting, as bacteria died or were recruited from the inactive to the active community. The duration of the dry summer conditions affected the diversity and phylogenetic clustering of the inactive microbial community and its functional potential, likely indicating long-lasting effects on ecosystem stability.