Wet-up response of the microbial community is shaped by soil dry-down patterns

Background/Question/Methods The massive soil CO2 efflux associated with rewetting dry soils after the dry summer period significantly contributes to the annual carbon budget of Mediterranean grasslands. Rapid reactivation of soil heterotrophic activity and available carbon are both required to fuel the CO2 pulse. Better understanding of the effects of altered summer precipitation on the metabolic state of indigenous microorganisms may be important in predicting future changes in carbon cycling. We investigated the effects of a controlled rewetting event on the soil CO2efflux pulse and on the present (DNA-based) and potentially active (rRNA-based) soil bacterial and fungal communities in int…