在地球系统模型中,陆地固定的戏剧性偏差是由自然同位素签名揭示的
Maoyuan Feng1,2,3, Shushi Peng1,2, Philippe Ciais4,5
1Sino-French Institute for Earth System Science, College of Urban and Environmental Sciences, and Laboratory for Earth Surface Processes, Peking University, Beijing 100871, China.
National science review
|December 18, 2025
概括
生物固定 (BNF) 对生态系统至关重要,但人们对其了解甚少. 这项研究使用同位素来揭示温度和菌根真菌作为关键驱动因素,发现地球系统模型低估了全球BNF.
科学领域:
- 生态生态学 生态生态学
- 生物地质化学生物地质化学
- 环境科学 环境科学
背景情况:
- 生物固定 (BNF) 是陆地生态系统中新活性的主要来源.
- 目前对BNF的估计是不确定的,因为人们对驱动因素和控制机制的理解不足.
研究的目的:
- 用同位素质量平衡来估计自然陆地生态系统中的BNF率.
- 确定控制共生BNF在总获取中的部分的关键驱动因素.
- 将基于同位素的BNF估计与来自地球系统模型 (ESM) 的估计进行比较.
主要方法:
- 扩展 (N) 同位素质量平衡理论以估计BNF率.
- 采用贝叶斯方法,使用植物 (δP) 和土壤 (δS) 的天然N同位素比率 (δ15N).
- 分析了来自18个森林地点的数据和对dP和dS的全球观测.
主要成果:
- 共生BNF (fBNFs) 的分量主要由温度 (29%) 和菌根真菌 (14%) 控制.
- 较冷的气候和较高的菌丰度与较低的fBNF相关.
- 来自自然陆地生态系统的全球总BNF估计为78.289.8 Tg N yr-1,这表明CMIP6模型低估了BNF至少18%.
结论:
- 温度和菌根真菌是BNF空间分布的重要调节者.
- 在BNF和菌根N吸收之间存在竞争关系,ESM中经常缺少的因素.
- 调查结果强调需要改进ESM中的BNF模拟,以便更准确地预测气候变化.
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