Organic Carbon Burial With Reactive Iron Across Global Environments
Organic Carbon Burial With Reactive Iron Across Global Environments
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DOI：
10.1029/2022gb007447
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发表时间：
2022-11
影响因子：
5.2
通讯作者：
Jack Longman;J. Faust;C. Bryce;W. Homoky;C. März
中科院分区：
文献类型：
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作者：
Jack Longman;J. Faust;C. Bryce;W. Homoky;C. März
有机碳（OC）在海洋和陆地沉积物中的保存通过与活性铁（FeR）的结合而增强。OC与FeR的关联（OC‐FeR）提供物理保护并阻碍微生物降解。松散海洋沉积物中储存的所有OC中约有20%和第四纪陆相沉积物中存在的所有OC中有40%以OC - FeR形式保存，但在全球沉积环境中，这一数值从10%到80%不等。本文利用已发表的碳含量与碳通量、碳埋藏和概率模型，对海洋和陆地环境中全球碳-碳埋藏率进行了新的评估。我们估计海洋OC - FeR汇量在31 - 70 Mt C / yr - 1之间（平均52 Mt C / yr - 1），陆地OC - FeR汇量在146 - 917 Mt C / yr - 1之间（平均446 Mt C / yr - 1）。在海洋环境中，大陆架（平均17mt C yr - 1）和三角洲/河口环境（平均11mg C yr - 1）是OC - fe埋藏的主要环境。在陆地上，农田（279mt C yr - 1）和草地（121mt C yr - 1）主导着OC - fe掩埋预算。地球系统在地质时期的变化影响了OC - FeR池，特别是在海洋环境中。例如，剧烈的火山喷发期可能导致海洋沉积物中净OC - fe埋藏增加。我们的工作强调了OC - FeR在海洋碳埋藏中的重要性，并证明了OC - FeR埋藏率在陆地环境中可能要大一个数量级，但这里的OC - FeR储量对气候变化的人为影响最为敏感。
Preservation of organic carbon (OC) in marine and terrestrial deposits is enhanced by bonding with reactive iron (FeR). Association of OC with FeR (OC‐FeR) provides physical protection and hinders microbiological degradation. Roughly 20% of all OC stored in unconsolidated marine sediments and 40% of all OC present in Quaternary terrestrial deposits is preserved as OC‐FeR, but this value varies from 10% to 80% across global depositional environments. Here, we provide a new assessment of global OC‐FeR burial rates in both marine and terrestrial environments, using published estimates of OC associated with FeR, carbon burial, and probabilistic modeling. We estimate the marine OC‐FeR sink between 31 and 70 Mt C yr−1 (average 52 Mt C yr−1), and the terrestrial OC‐FeR sink at between 146 and 917 Mt C yr−1 (average 446 Mt C yr−1). In marine environments, continental shelves (average 17 Mt C yr−1) and deltaic/estuarine environments (average 11 Mg C yr−1) are the primary settings of OC‐FeR burial. On land, croplands (279 Mt C yr−1) and grasslands (121 Mt C yr−1) dominate the OC‐FeR burial budget. Changes in the Earth system through geological time impact the OC‐FeR pools, particularly in marine settings. For example, periods of intense explosive volcanism may lead to increased net OC‐FeR burial in marine sediments. Our work highlights the importance of OC‐FeR in marine carbon burial and demonstrates how OC‐FeR burial rates may be an order of magnitude greater in terrestrial environments, but here OC‐FeR stocks are most sensitive to the anthropogenic impacts of climatic change.