Trace Metal Evidence for Deglacial Ventilation of the Abyssal Pacific and Southern Oceans
Trace Metal Evidence for Deglacial Ventilation of the Abyssal Pacific and Southern Oceans
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DOI：
10.1029/2021pa004226
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发表时间：
2021-08
影响因子：
3.5
通讯作者：
F. Pavia;Shouyi Wang;J. Middleton;R. Murray;R. Anderson
中科院分区：
文献类型：
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作者：
F. Pavia;Shouyi Wang;J. Middleton;R. Murray;R. Anderson
长期以来，深海一直被认为是储存更新世冰川时期从大气中去除的二氧化碳（CO2）的水库。冰川大气中的CO2向海洋中的去除可能受到海面大量营养素利用程度的增加和深海中呼吸的CO2储存量的增加（称为生物泵效率的提高）的调节。冰川期生物泵效率的提高在深海中最容易使用氧浓度的代理记录，这与呼吸CO2水平直接相关。我们的文件增强存储的呼吸CO2在末次冰期最大值（LGM）在太平洋南部海洋和最深的赤道太平洋使用记录的冰消自生锰，形成残留的峰值在底层水氧（BWO）浓度的增加。这些峰被发现在深度和区域，其他氧化历史一直模棱两可，由于成岩蚀变的自生铀，另一个代理BWO。我们的研究结果表明，整个深海太平洋低于约1 000米的富集呼吸二氧化碳和贫氧在末次冰期。在过去五次冰消期中，赤道太平洋深部存在自生Mn富集，这表明深海中呼吸的CO2的储存是晚更新世冰期的普遍特征。
The deep ocean has long been recognized as the reservoir that stores the carbon dioxide (CO2) removed from the atmosphere during Pleistocene glacial periods. The removal of glacial atmospheric CO2 into the ocean is likely modulated by an increase in the degree of utilization of macronutrients at the sea surface and enhanced storage of respired CO2 in the deep ocean, known as enhanced efficiency of the biological pump. Enhanced biological pump efficiency during glacial periods is most easily documented in the deep ocean using proxies for oxygen concentrations, which are directly linked to respiratory CO2 levels. We document the enhanced storage of respired CO2 during the Last Glacial Maximum (LGM) in the Pacific Southern Ocean and deepest Equatorial Pacific using records of deglacial authigenic manganese, which form as relict peaks during increases in bottom water oxygen (BWO) concentration. These peaks are found at depths and regions where other oxygenation histories have been ambiguous, due to diagenetic alteration of authigenic uranium, another proxy for BWO. Our results require that the entirety of the abyssal Pacific below approximately 1,000 m was enriched in respired CO2 and depleted in oxygen during the LGM. The presence of authigenic Mn enrichment in the deep Equatorial Pacific for each of the last five deglaciations suggests that the storage of respired CO2 in the deep ocean is a ubiquitous feature of late‐Pleistocene ice ages.