土壤碳动力被古代碳量化重新塑造
Yoann Copard1, Christine Hatté2,3, Lauric Cécillon4,5
1Univ. Rouen Normandie, Université Caen Normandie, CNRS, Normandie Univ., Rouen, France.
Global change biology
|September 3, 2025
概括
古老的无放射性碳有机碳 (aOC) 偏向于土壤碳年代. 对于aOC来说,土壤碳的年龄比以前想象的要小,改善了气候模型.
科学领域:
- 地质化学
- 土壤科学
- 气候科学
背景情况:
- 土壤有机碳 (SOC) 是缓解气候变化的关键陆地储量.
- SOC的放射性碳年代是必不可少的,但由古老的无放射性碳有机碳 (aOC) 复杂化.
- 目前的SOC年龄估计可能是不准确的,原因是未定位的aOC.
研究的目的:
- 量化土壤中aOC的全球分布.
- 通过计算aOC来纠正基于放射性碳的SOC年龄估计.
- 将经验数据与地球系统模型参数化进行协调.
主要方法:
- 将线性混合方程应用于来自放射性碳数据库的313个全球土壤样本.
- 量化 aOC 含量及其对不同土壤深度的总 SOC 的贡献.
- 减去aOC贡献以计算修正的SOC年龄.
主要成果:
- 平均aOC含量为2.4 mg/g,在上层土壤中占11%,在地下土壤中占25%,在深层土壤中占50%以上.
- 安多和冷具有特别高的aOC含量.
- 非aOC碳的修正平均年龄为290年,比以前的估计年龄 (31004830年) 轻得多.
结论:
- 有氧化碳的存在显著扭曲了基于放射性碳的SOC年龄估计.
- 校正的SOC年龄与其他同位素代理和经验数据更好地一致.
- 这项研究为改善气候建模提供了对土壤碳动态的更准确的理解.
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