Deepwater Expansion and Enhanced Remineralization in the Eastern Equatorial Pacific During the Last Glacial Maximum
Deepwater Expansion and Enhanced Remineralization in the Eastern Equatorial Pacific During the Last Glacial Maximum
复制标题
末次盛冰期赤道东太平洋深水扩张和再矿化增强
DOI：
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发表时间：
2018
影响因子：
3.5
通讯作者：
M. Bizimis
中科院分区：
文献类型：
--
作者：
N. Umling;R. Thunell;M. Bizimis
发表的估计中深度沃茨的放射性碳含量表明，在末次盛冰期（LGM; 24.0-18.1 ka）在多个地点的通风减少。冰川通风的减少会使呼吸的碳在这些沃茨中积累。随后的冰消期释放到大气中的呼吸碳库可以解释所观察到的大气中二氧化碳的增加和大气中放射性碳含量的下降。然而，年龄模型错误和14 C耗尽的地幔碳的释放也被引用为观测到的中层放射性碳耗尽的可能解释，质疑深海在LGM期间储存呼吸碳的作用。对底栖有孔虫碳同位素值（δ 13 C）和镉/钙（Cd/Ca）比值的联合测量提供了一种方法，可以将水团的海气成分与矿化度的变化隔离开来。在这里，我们使用来自赤道东太平洋的底栖有孔虫δ 13 C和Cd/Ca记录来限制末次冰期-间冰期过渡期间的矿化和水团混合的变化。这些记录补充了有孔虫自生涂层的元素测量，以监测沉积后底层水性质的变化。我们的研究结果表明，增加深水沃茨在中层深度与南大洋翻转环流的上部和下部分支之间的边界变浅。此外，我们的记录表明，在末次盛冰期的中层沃茨中有机质的矿化增加，这表明呼吸碳在通风减少的时期下在中层沃茨中积累。
Published estimates of the radiocarbon content of middepth waters suggest a decrease in ventilation in multiple locations during the last glacial maximum (LGM; 24.0–18.1 ka). Reduced glacial ventilation would have allowed respired carbon to accumulate in those waters. A subsequent deglacial release of this respired carbon reservoir to the atmosphere could then account for the observed increases in atmospheric CO2 and decline in atmospheric radiocarbon content. However, age model error and a release of 14C‐depleted mantle carbon have also been cited as possible explanations for the observed middepth radiocarbon depletions, calling into question the deep ocean's role in storing respired carbon during the LGM. Joint measurements of benthic foraminiferal carbon isotope values (δ13C) and cadmium/calcium (Cd/Ca) ratios provide a method for isolating the air‐sea component of a water mass from changes in remineralization. Here we use benthic foraminiferal δ13C and Cd/Ca records from the eastern equatorial Pacific to constrain changes in remineralization and water‐mass mixing over the last glacial‐interglacial transition. These records are complemented with elemental measurements of the authigenic coatings of foraminifera to monitor postdepositional changes in bottom water properties. Our results suggest an increase of deep waters at midwater depths consistent with a shoaling of the boundary between the upper and lower branches of Southern Ocean overturning circulation. Additionally, our records demonstrate increased organic matter remineralization in middepth waters during the LGM, suggesting that respired carbon did accumulate in middepth waters under periods of reduced ventilation.
影响因子：
--
作者：
Burke, Andrea;Stewart, Andrew L.;Thompson, Andrew F.
通讯作者：
Thompson, Andrew F.
关于古海洋学中底栖有孔虫 Ύ´13C 的使用：主要代理关系的限制
DOI：
10.1144/sp303.9
发表时间：
2008
期刊：
影响因子：
--
作者：
Mackensen
通讯作者：
Mackensen
影响因子：
3.5
作者：
Osborne, Anne H.;Hathorne, Ed C.;Frank, Martin
通讯作者：
Frank, Martin