旧的二氧化碳从加拿大北极的一个主要河流系统的泄漏
Sanjeev Dasari1, Mark H Garnett2, Robert G Hilton1
1Department of Earth Sciences, University of Oxford, Oxford OX1 3AN, UK.
PNAS nexus
|April 15, 2024
概括
北极的变暖加快了永久土的融化,将古老的碳释放到河流中. 我们的研究表明,这种古老的碳通过麦肯齐河出口,主要是作为二氧化碳,突出了温室气体释放的重要途径.
科学领域:
- 环境科学 环境科学
- 地质化学 地质化学
- 北极研究研究北极研究
背景情况:
- 加拿大北极地区正在经历快速变暖,导致永久土融化.
- 永久土的融化释放了土壤和岩石中储存的古老碳.
- 河流网络是运输碳和温室气体的关键通道.
研究的目的:
- 调查麦肯齐河系统中溶解无机碳 (DIC) 的同位素特性.
- 了解永久土融化的老化碳动员的来源和途径.
- 量化不同来源对北极河流中老化碳池的贡献.
主要方法:
- 在DIC中分析放射性碳 (14C) 活性,以确定碳年龄.
- 对DIC的稳定同位素分析,以确定碳来源和过程.
- 在河流运输过程中对二氧化碳脱气和分离的评估.
主要成果:
- 在夏季期间,在麦肯齐河 (Mackenzie River) 发生了大量的"旧"碳出口 (平均为公元前2,380±1,040年).
- 稳定同位素数据表明,老化的碳从支流中以CO2的形式脱气.
- 60 ± 10%的老化碳可能源自生物圈有机碳氧化,碳酸气候和大气交换的贡献.
结论:
- 像麦肯齐河这样水文连接的水域是从北极永久土中调动老化碳的关键途径.
- 从河流支流中脱气的二氧化碳是释放老化碳的重要过程.
- 了解这些碳动员途径对于预测北极变暖的温室气体动态至关重要.
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