Ecosystem productivity has a stronger influence than soil age on surface soil carbon storage across global biomes

8 páginas.- 3 figuras.- 81 referencias.- Supplementary information The online version contains supplementary material available at https://doi.org/10.1038/s43247-022-00567-7
Interactions between soil organic matter and minerals largely govern the carbon sequestration capacity of soils. Yet, variations in the proportions of free light (unprotected) and mineral-associated (protected) carbon as soil develops in contrasting ecosystems are poorly constrained. Here, we studied 16 long-term chronosequences from six continents and found that the ecosystem type is more important than soil age (centuries to millennia) in explaining the proportion of unprotected and mineral-associated carbon fractions in surface soils across global biomes. Soil carbon pools in highly productive tropical and temperate forests were dominated by the unprotected carbon fraction and were highly vulnerable to reductions in ecosystem productivity and warming. Conversely, soil carbon in low productivity, drier and colder ecosystems was dominated by mineral-protected carbon, and was less responsive to warming. Our findings emphasize the importance of conserving ecosystem productivity to protect carbon stored in surface soils. Soil organic carbon pools in productive tropical and temperate forests are more labile than those in drier colder ecosystems where mineral-protected organic carbon dominates, according to analyses of 16 long-term chronosequences from six continents.
M.D.-B. and P.G.-P. were supported by Ramón y Cajal grants from the Spanish Ministry of Science and Innovation (RYC2018-025483-I and RYC2018-024766-I). This project received funding from the European Union’s Horizon 2020 research and innovation program under the Marie Skłodowska-Curie grant agreement 702057 and the Spanish State Plan for Scientific and Technical Research and Innovation (2013–2016), award ref. AGL201675762-R (AEI/FEDER, UE). M.D.-B. acknowledges support from the Spanish Ministry of Science and Innovation for the I+D+i project PID2020-115813RA-I00 funded by MCIN/AEI/10.13039/501100011033. M.D.-B. is also supported by a project of the Fondo Europeo de Desarrollo Regional (FEDER) and the Consejería de Transformación Económica, Industria, Conocimiento y Universidades of the Junta de Andalucía (FEDER Andalucía 2014–2020 Objetivo temático “01—Refuerzo de la investigación, el desarrollo tecnológico y la innovación”) associated with the research project P20_00879 (ANDABIOMA). C.P. acknowledges support from the EU H2020 research and innovation programme under grant agreement No 101000224. F.B. acknowledges support from CSIC i-LINK + 2018 (LINKA20069), PID2020-114942RB-I00 funded by MCIN/AEI/10.13039/501100011033 and Fundación Séneca from Murcia Province (19896/GERM/15).