Methane-derived authigenic carbonates – A case for a globally relevant marine carbonate factory
Methane-derived authigenic carbonates – A case for a globally relevant marine carbonate factory
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DOI：
10.1016/j.earscirev.2023.104487
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发表时间：
2023-08
影响因子：
12.1
通讯作者：
Sajjad Akam;E. Swanner;H. Yao;W. Hong;Jörn Peckmann
中科院分区：
文献类型：
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作者：
Sajjad Akam;E. Swanner;H. Yao;W. Hong;Jörn Peckmann
甲烷衍生自生碳酸盐（MDAC）降水是海洋甲烷生产和消耗的重要组成部分，但MDAC对全球海洋碳循环的相对意义尚不清楚。本文从全球海洋碳生物地球化学的角度对MDAC进行了综述和展望。MDAC的形成是浅层硫酸盐带碳-硫（c单键）耦合和深层甲烷沉积物碳-硅（c单键- si）耦合的结果和存档。MDAC在现代海洋中固碳量为3.93 Tmol C yr - 1（范围2.34 ~ 5.8 Tmol C yr - 1），是海洋沉积物中第三大碳埋藏机制。该埋藏与大陆边缘29%（11-57%）的有机碳和10%（6-23%）的骨架碳酸盐碳相比较。MDAC地层也是底栖生物碱度的重要储存库，因此是导致底栖水酸化的潜在因素。在过去的50年里，我们对MDAC对全球生物地球化学循环影响的理解已经从传统上被认为是渗绿洲环境中的被动碳封存机制演变为现在被认为是一个从深层沉积物扩展到底层水的动态碳酸盐工厂——一个自前寒武纪以来一直在运行的工厂。我们认为有必要改进MDAC成藏速率和相关碳酸盐生物地球化学参数的区域尺度量化，以便在MDAC勘探的下一阶段将其纳入现在和古碳预算。
Precipitation of methane-derived authigenic carbonates (MDAC) is an integral part of marine methane production and consumption, but MDAC's relative significance to the global marine carbon cycle is not well understood. Here we provide a synthesis and perspective to highlight MDAC from a global marine carbon biogeochemistry viewpoint. MDAC formation is a result and archive of carbon‑sulfur (Csingle bondS) coupling in the shallow sulfatic zone and carbon‑silicon (Csingle bondSi) coupling in deeper methanic sediments. MDAC constitute a carbon sequestration of 3.93 Tmol C yr−1(range 2.34–5.8 Tmol C yr−1) in the modern ocean and are the third-largest carbon burial mechanism in marine sediments. This burial compares to 29% (11–57%) organic carbon and 10% (6–23%) skeletal carbonate carbon burial along continental margins. MDAC formation is also an important sink for benthic alkalinity and, thereby, a potential contributor to bottom water acidification. Our understanding of the impact of MDAC on global biogeochemical cycles has evolved over the past five decades from what was traditionally considered a passive carbon sequestration mechanism in a seep-oasis setting to what is now considered a dynamic carbonate factory expanding from deep sediments to bottom waters—a factory that has been operational since the Precambrian. We present a strong case for the need to improve regional scale quantification of MDAC accumulation rates and associated carbonate biogeochemical parameters, leading to their incorporation in present and paleo‑carbon budgets in the next phase of MDAC exploration.