Oxygen history off Baja California over the last 80 kyr: A new foraminiferal-based record: Oxygen History in the California Margin
Oxygen history off Baja California over the last 80 kyr: A new foraminiferal-based record: Oxygen History in the California Margin
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DOI：
10.1002/2016pa003034
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发表时间：
2017-03
期刊：
影响因子：
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通讯作者：
M. Tetard;L. Licari;L. Beaufort
中科院分区：
文献类型：
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作者：
M. Tetard;L. Licari;L. Beaufort
在末次冰期，北太平洋东部（ENP）的氧气最小区（OMZ）的强度经历了强烈的变化，反映了出口生产（O2消耗）和水团通风（O2更新）之间平衡的变化。在本文中，我们提出了一个新的底栖有孔虫组合记录，从MD 02 -2508孔，回收自墨西哥下加利福尼亚太平洋斜坡。该记录反映了过去80 kyr期间OMZ北方边界的氧气状况。我们在统计学上艾德三种组合，其特征是缺氧，亚氧和氧化条件，我们用来产生太平洋东北部[O 2 ]的第一个半定量重建。结果表明，估算的[O2]与北格陵兰冰芯项目的δ 18 O记录具有一定的协变关系。氧浓度总体表现出中等值（~ 1 mL. L（cid：1）1）在stadials，达到~2 mL.L（cid：1）1在stadials对应于海因里希事件在大西洋。相反，在海间期间，核心位置的底层沃茨中的氧气严重耗尽（< 0.5 mL.L（cid：1）1）。底栖有孔虫的丰度随着地球化学示踪剂（Cd/Al比率）记录的出口产量的增加而增加。这种输出生产信号增加（减少）与下降（上升）在[O 2 ]在interstadials（stadials），这表明这两个参数之间的关系，在这些间隔。通气对氧合的影响也是一个关键因素。O2脉冲建议的系列/螺旋测试比和丰富的含氧物种的下芯记录可以解释增强通风在海因里希stadials，在最新的建模为基础的海洋环流重建。
The intensity of the Oxygen minimum zone (OMZ) of the eastern North Paci fi c (ENP) experienced strong variations during the last glacial, mirroring changes in the balance between export production (O 2 consumption) and water mass ventilation (O 2 renewal). In this paper we present a new benthic foraminiferal assemblages record from Core MD02-2508, recovered from the Paci fi c slope off Baja California, Mexico. The record re fl ects oxygen conditions at the northern limit of the OMZ during the last 80kyr. We statistically identi fi ed three assemblages, characteristic of dysoxic, suboxic, and oxic conditions, which we used to produce the fi rst semiquantitative reconstruction of [O 2 ] for the northeastern Paci fi c Ocean. Our results show that the estimated [O 2 ] covaries with δ 18 O records from the North Greenland Ice Core Project. Oxygen concentrations overall exhibit moderate values (~1mL.L (cid:1) 1 ) during stadials, reaching ~2 mL.L (cid:1) 1 during stadials corresponding to Heinrich events in the Atlantic Ocean. Conversely, bottom waters at the core location were strongly depleted in oxygen ( < 0.5 mL.L (cid:1) 1 ) during interstadials. Benthic foraminiferal abundance increased with higher export production as recorded by geochemical tracers (Cd/Al ratio). This export production signal increases (decreases) with a fall (rise) in [O 2 ] during interstadials (stadials), suggesting a relationship between both parameters during these intervals. The in fl uence of ventilation on oxygenation is also a key player. O 2 pulses suggested by the downcore records of serial/spiral test ratio and abundance of oxic species may be explained by enhanced ventilation during Heinrich stadials, in agreement with latest modeling-based oceanic circulation reconstructions.