Droughts have become more intense and frequent since the 1970s and are predicted to become even more intense and frequent, creating an urgency to understand the impacts of increasing water limitations. The objective of this study was to understand whether ecosystem carbon cycling is able to recover without intervention post drought or if conservation efforts are needed. To fulfill this objective, we quantified measures of carbon cycling during the first year of recovery (ambient rainfall) in an experiment that had previously undergone four years of intensive drought. This experiment had three treatments: (1) ambient rainfall, (2) chronic drought, which reduced rainfall by 66% the entire growing season, and (3) intense drought, which reduced rainfall completely until 45% of mean annual precipitation had been reached. To understand recovery of the carbon cycle in this experiment, we measured soil respiration, microbial respiration, carbon mineralization, and potential enzymatic activities of carbon cleaving enzymes monthly over the growing season.
Results/Conclusions
The chronic treatment saw decreases in microbial respiration at the end of the growing season and increases in activity of carbon cleaving enzymes at the beginning of the season with recovery at the end of the season, while the intense treatment saw decreases in soil respiration and microbial respiration at the beginning of the season and recovery at the end. These results indicate that both the chronic and intense drought treatments are experiencing decreases in carbon cycling activity at the beginning of the season but experienced quick recovery in ambient rainfall conditions. Future directions for this project include understanding nitrogen cycling recovery and microbial community composition recovery.