Dryland carbon cycling: The role of extreme events when fluxes are big and pools are small

Dryland soils, particularly aridisols, have characteristically low soil organic carbon (C) pools. The action in dryland C cycling is thus skewed toward living biota and away from soil carbon. This creates a poorly buffered and variable system that is sensitive to extreme events. For C cycling, extreme events may be characterized less by single episodes of drought or rainfall, and more by idiosyncratic climatic sequences that drive large C gains or losses. Predicting the effects of such sequences requires detailed knowledge of C flux partitioning, an area with substantial knowledge gaps for dryland systems, especially below ground.