Seminar: Hui Wang

Drylands store substantial organic and inorganic carbon, but the persistence and vulnerability of these pools remain poorly constrained. Using radiocarbon measurements across global and regional dryland gradients, this study shows that soil carbon becomes older with increasing aridity due to reduced recent carbon inputs, while mineral protection, microbial processing, and carbonate chemistry further regulate carbon persistence. Old organic carbon can still contribute to soil respiration, and inorganic carbon can exchange with modern soil CO2 through dissolution–reprecipitation. These findings show that dryland soil carbon is dynamic rather than inert and that radiocarbon provides critical constraints for predicting carbon vulnerability under climate and land-use change.