Persistence and turnover of soil organic carbon in global drylands
Abstract
Abstract Reliable predictions of dryland carbon fluxes require understanding the persistence and turnover of soil organic carbon (SOC). We measure radiocarbon to quantify the age of SOC and CO 2 released from soil respiration at 97 dryland sites across six continents. Here we show that bulk SOC contains little C fixed in the past 60 years, while respired CO 2 originates from both bomb-derived recent C and millennia-old C, challenging the idea that old C is chemically or physically protected. Radiocarbon suggests mean ages of ~2100 years for bulk SOC and ~520 years for respired CO 2 , the latter far older than machine-learning (<50 years) or Earth system models predict. Aridity, net primary productivity, and SOC content are dominant predictors for radiocarbon signatures, with abrupt shifts to older C beyond an aridity threshold of ~0.87. Our findings underscore the need to incorporate the vulnerability of older carbon into models and land management strategies.
Article Details
Authors (33)
Hui Wang
Fernando T. Maestre
Nan Lu
Guang Zhao
Yangjian Zhang
Sergio Asensio
De Shorn E. Bramble
Weiliang Chen
Michaela A. Dippold
David J. Eldridge
Juan J. Gaitán
Miguel García-Gómez
Beatriz Gozalo
Nicolas Gross
Emilio Guirado
Yoann Le Bagousse-Pinguet
Jaime Martínez-Valderrama
Betty J. Mendoza
Victoria Ochoa
Cesar Plaza
Hugo Saiz
Marion Schrumpf
Carlos A. Sierra
Andrés Tangarife-Escobar
Enrique Valencia
Sophie F. von Fromm
Cong Wang
Key Laboratory of Preclinical Study for New Drugs of Gansu Province, School of Basic Medical Sciences & Research Unit of Peptide Science, Chinese Academy of Medical Sciences, 2019RU066
Kai Wang
Yunqiang Wang
Sönke Zaehle
Bojie Fu
Susan Trumbore
Department Biogeochemical Processes, Max-Planck-Institute for Biogeochemistry
Jianbei Huang