期刊
GLOBAL CHANGE BIOLOGY
卷 28, 期 13, 页码 4180-4193出版社
WILEY
DOI: 10.1111/gcb.16183
关键词
carbon cycling; global warming; mineral association; organic matter stability; paleosol; physical protection
资金
- National Natural Science Foundation of China [32171601]
- National Key Research and Development Program of China [2016YFC0500700, 2017YFA0604802]
- Spanish government project [PID2019-110521GB-I00]
- Catalan government project [SGR2017-1005]
- Fundacion Ramon Areces grant ELEMENTAL-CLIMATE.
- RUDN University Strategic Academic Leadership Program
- West-Siberian Interregional Science and Education Center's [89-DON 1]
- Stability and Functions of Soil Carbon in Agroecosystems of Russia (CarboRus) [075-15-2021-610]
This study reveals a nonlinear decrease in the temperature sensitivity of soil organic matter decomposition with increasing soil age. The availability of organic matter is found to be regulated by soil age, which in turn influences the temperature sensitivity.
Temperature sensitivity (Q(10)) of soil organic matter (SOM) decomposition is an important parameter in models of the global carbon (C) cycle. Previous studies have suggested that substrate quality controls the intrinsic Q(10), whereas environmental factors can impose large constraints. For example, physical protection of SOM and its association with minerals attenuate the apparent Q(10) through reducing substrate availability and accessibility ([S]). The magnitude of this dampening effect, however, has never been quantified. We simulated theoretical Q(10) changes across a wide range of [S] and found that the relationship between Q(10) and the log(10)-transformed [S] followed a logistic rather than a linear function. Based on the unique Holocene paleosol chronosequence (7 soils from ca. 500 to 6900 years old), we demonstrated that the Q(10) decreased nonlinearly with soil age up to 1150 years, beyond which Q(10) remained stable. Hierarchical partitioning analysis indicated that an integrated C availability index, derived from principal component analysis of DOC content and parameters reflecting physical protection and mineral association, was the main explanatory variable for the nonlinear decrease of Q(10) with soil age. Microbial inoculation and C-13-labelled glucose addition showed that low C availability induced by physical protection and minerals association attenuated Q(10) along the chronosequence. A separate soil incubation experiment indicated that Q(10) increased exponentially with activation energy (E-a) in the modern soil, suggesting that SOM chemical complexity regulates Q(10) only when C availability is high. In conclusion, organic matter availability strongly decreased with soil age, whereas Michelis-Menten kinetics defines the Q(10) response depending on C availability, but Arrhenius equation describes the effects of increasing substrate complexity.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据