0000000000908924
AUTHOR
Catherine Osborne
Responses of soil bacterial and fungal communities to extreme soil drought and rewetting
Question: The patterns of resource allocation and activity of the soil microbial community over the dry summer in Mediterranean grasslands are still largely unknown. The microbial response to summer desiccation reflects adaptation strategies, setting the stage for a large rainfall-induced soil CO2 pulse upon rewetting, an important component of the ecosystem carbon budget. Methods: In three California annual grasslands, the present (DNA-based) and potentially active (RNA-based) soil bacterial and fungal communities were tracked over a summer season and in response to controlled rewetting of intact soil cores. Phylogenetic marker genes for bacterial (16S) and fungal (28S) RNA and DNA were se…
Microbial community dynamics induced by rewetting dry soil: summer precipitation matters
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 CO2 efflux pulse and on the present (DNA-based) and potentially active (rRNA-based) soil bacterial and fungal communities in intact soil cores previously s…