Removal of methane through hydrological, microbial, and geochemical processes in the shallow sediments of pockmarks along eastern Vestnesa Ridge (Svalbard)
Removal of methane through hydrological, microbial, and geochemical processes in the shallow sediments of pockmarks along eastern Vestnesa Ridge (Svalbard)
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DOI：
10.1002/lno.10299
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发表时间：
2016-11
影响因子：
4.5
通讯作者：
W. Hong;S. Sauer;G. Panieri;W. Ambrose;R. James;A. Plaza-Faverola;A. Schneider
中科院分区：
文献类型：
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作者：
W. Hong;S. Sauer;G. Panieri;W. Ambrose;R. James;A. Plaza-Faverola;A. Schneider
The recent discovery of methane sees in the Arctic region requires a better understanding of the fate of methane in marine sediments if we are to understand the contributions of methane to Arctic ecosystems and climate change. To this goal, we analyze pore water data from five sites along Eastern Vestnesa Ridge, a sediment drift off‐north‐west Svalbard, to quantify the consumption of dissolved methane across the sulfate‐methane‐transition‐zone which are 3–5 m below seafloor从研究的地点，我们使用运输模型来量化沉积物中的碳质量平衡，我们的模型结果表明，氢，微生物和地球化学过程/反应有效地从不同的时间尺度上逐渐流动的流动量来消除甲烷的碳。到渗流压力不平衡。这种向下流量通过在该深度范围内通过甲烷（AOM）氧化增强甲烷的消耗量。 ies碳酸盐的身份碳酸盐清除了由AOM生产的溶解的无机碳中的四分之一以上，并将其固定为沉积物中的身份碳酸盐，这一过程在地质时间内会隔离甲烷碳。
The recent discovery of methane seeps in the Arctic region requires a better understanding of the fate of methane in marine sediments if we are to understand the contributions of methane to Arctic ecosystems and climate change. To this goal, we analyze pore water data from five sites along eastern Vestnesa Ridge, a sediment drift off‐north‐west Svalbard, to quantify the consumption of dissolved methane across the sulfate‐methane‐transition‐zone which are 3–5 m below seafloor from the investigated sites. We use transport‐reaction models to quantify the hydrology as well as the carbon mass balance in the sediments. Pore water profiles and our model results demonstrate that hydrological, microbial, and geochemical processes/reactions efficiently remove methane carbon from fluid over different time scales. We interpret the nonsteady‐state behavior of the first 50–70 cm of our pore water profiles from the active sites as an annual scale downward fluid flow due to a seepage‐related pressure imbalance. Such downward flow supplies sulfate which enhances methane consumption through anaerobic oxidation of methane (AOM) within this depth range. Our steady‐state modeling confirms the efficiency of AOM in consuming dissolved methane in the upper 0.8–1.2 m of sediments. Based on the phosphate profiles, we estimate that AOM at the active pockmarks may have been operating for the last two to four centuries. Precipitation of authigenic carbonate removes more than a quarter of the dissolved inorganic carbon produced by AOM and fixes it as authigenic carbonate in the sediments, a process that sequestrates methane carbon over geological time.