氧化伪装了陆地有机物质,使其看起来像海洋一样
Aleksandar I Goranov1, Susan J Carter2, Ann Pearson2
1Department of Chemistry and Biochemistry, Old Dominion University, Norfolk, Virginia 23529, United States.
Environmental science & technology
|March 14, 2025
概括
陆地有机物 (TOM) 可以通过氧化转化为类似海洋的有机物,这挑战了以前关于海洋碳来源的假设. 这表明,比以前想象的更多的陆地碳进入海洋,影响了碳循环模型.
科学领域:
- 地质化学 地质化学
- 海洋学 海洋学 海洋学
- 生物地质化学生物地质化学
背景情况:
- 陆地有机物 (TOM) 出口到海洋被认为是最小的,在到达开放水域之前降解.
- 海洋有机碳 (δ13C值≥-22‰) 通常归因于藻类来源.
- 传统模型假设在海洋运输过程中,陆地素生物标志物和同位素特征 (δ13C) 的显著损失.
研究的目的:
- 为了调查氧化处理是否将TOM转化为类似海洋的签名.
- 挑战目前普遍认为陆地有机物对公开海洋的贡献有限的观点.
- 重新评估海洋有机物质的起源及其对全球碳模型的影响.
主要方法:
- 对8个陆地有机物样本进行了强烈的氧化梯度.
- 分析的化学成分 (木质素生物标志物,酸和含量) 和稳定的碳同位素特征 (δ13C).
- 模拟的碳损失与运输和沉积过程相一致.
主要成果:
- 氧化加工在60%以上的碳损失消除了陆地来源指标.
- 其余物表现出类似海洋的化学特性 (富有和) 和同位素特性 (δ13C丰富度为4-9‰).
- 陆地生物标志物和同位素特征丢失,模仿海洋有机物质.
结论:
- 氧化转化可以使陆地有机物与海洋来源无法区分.
- 传统的双端混合模型可能会高估海洋衍生的碳,低估陆地贡献.
- 海洋有机物质的更大一部分可能来自陆地来源,这需要对全球碳循环和封存模型进行修订.
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