在LGM期间,赤道印度洋热流线中的可变通风年龄在LGM期间变化
J Raddatz1, E Beisel2, M Butzin3
1Institute of Geosciences, Goethe University Frankfurt, Altenhöferallee 1, 60438, Frankfurt Am Main, Germany. Raddatz@em.uni-frankfurt.de.
Scientific reports
|July 14, 2023
概括
在最后的冰川最大期,印度洋热带层比以前理解的要老得多,含有丰富碳的水域. 这一发现表明,浅层海洋层在冰川碳减排中发挥了更大的作用.
科学领域:
- 古海洋学是古海洋学.
- 海洋地球化学 海洋地球化学
- 气候科学 气候科学
背景情况:
- 冰河时代大气中二氧化碳的变化与海洋碳捕获有关.
- 以前的模型建议深海储存碳,但很大一部分可能存在于热流层.
- 热水的碳储存能力仍然没有得到充分的量化.
研究的目的:
- 调查在最后的冰川最大期 (LGM) 期间赤道印度洋热带的碳储存和通风动态.
- 评估热带水对冰川碳吸收的贡献.
- 评估基于放射性碳的年龄模型的准确性.
主要方法:
- 在马尔代夫群岛附近约450米深的冷水珊瑚中配对的230Th/U和14C测年.
- 放射性碳耗尽 (Δ14C, ΔΔ14C) 和地大气层 (Batm) 年龄的计算.
- 使用珊瑚地化学分析热线通风的分析.
主要成果:
- 在LGM期间,珊瑚数据揭示了放射性碳贫乏的热流层,水年龄为500-2100年 (Batm).
- 这表明,与今天 (约380年) 相比,热流层中的水域显著更古老,可能更富含碳.
- 发现热链通风年龄比先前估计的变化要多一等级.
结论:
- 印度洋LGM热带作为一个重要的碳储库,有助于冰川碳吸收.
- 深水的可变深层上游,含有大量的呼吸碳,可能解释了耗尽的热流层.
- 这些发现挑战了现有的基于放射性碳的年龄模型,并突出了上热线水在过去气候动态中的重要性.
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