I/Ca in epifaunal benthic foraminifera: A semi-quantitative proxy for bottom water oxygen in a multi-proxy compilation for glacial ocean deoxygenation
I/Ca in epifaunal benthic foraminifera: A semi-quantitative proxy for bottom water oxygen in a multi-proxy compilation for glacial ocean deoxygenation
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表层底栖有孔虫中的 I/Ca：冰川海洋脱氧多代理汇编中底层水氧的半定量代理
DOI：
10.1016/j.epsl.2019.116055
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发表时间：
2020
影响因子：
5.3
通讯作者：
Thomas, Ellen
中科院分区：
文献类型：
--
作者：
Lu, Wanyi;Rickaby, Rosalind E.M.;Hoogakker, Babette A.A.;Rathburn, Anthony E.;Burkett, Ashley M.;Dickson, Alexander J.;Martínez-Méndez, Gema;Hillenbrand, Claus-Dieter;Zhou, Xiaoli;Thomas, Ellen
全球海洋中溶解氧的下降(海洋脱氧)是全球变暖的一个潜在后果，可能对海洋生物地球化学和海洋生态系统产生重要影响。目前的气候模型在不同的时间尺度上对未来脱氧的轨迹并不一致，部分原因是海洋环流、生产力和有机物呼吸变化的复杂、关联影响中的不确定性。更新世冰期海洋氧气水平的更多(半)定量重建可能会对我们对海洋氧气对气候变化的响应的机制理解提供一个关键的考验。即使是最有希望的底层水氧(BWO)指标也有局限性，这就需要新的指标开发和多指标汇编来评估冰川海洋的氧合作用。我们利用全新世底栖有孔虫研究了Cibiididesspp中的I/Ca。作为BWO代理。我们认为，低I/Ca(例如，<；3μ摩尔/摩尔)与底栖有孔虫碳同位素梯度和/或有孔虫测试中的表面孔隙面积百分比(例如，>；15%)相结合，可以提供对过去海洋中低BWO(例如，<；∼50μ摩尔/公斤)的半定量估计。我们提供了五个岩芯的I/Ca记录和多项代理数据的全球汇编，表明冰川时期底层水域的含氧量普遍较低，大西洋和太平洋的部分海域的氧气含量较低(<；∼50μ/kg)。水团通风和环流可能对冰川深太平洋和南大西洋的除氧很重要，而有机物的强化再矿化可能对减少大西洋内陆的含氧量产生了更大的影响。
The decline in dissolved oxygen in global oceans (ocean deoxygenation) is a potential consequence of global warming which may have important impacts on ocean biogeochemistry and marine ecosystems. Current climate models do not agree on the trajectory of future deoxygenation on different timescales, in part due to uncertainties in the complex, linked effects of changes in ocean circulation, productivity and organic matter respiration. More (semi-)quantitative reconstructions of oceanic oxygen levels over the Pleistocene glacial cycles may provide a critical test of our mechanistic understanding of the response of oceanic oxygenation to climate change. Even the most promising proxies for bottom water oxygen (BWO) have limitations, which calls for new proxy development and a multi-proxy compilation to evaluate glacial ocean oxygenation. We use Holocene benthic foraminifera to explore I/Ca inCibicidoidesspp. as a BWO proxy. We propose that low I/Ca (e.g., <3 μmol/mol) in conjunction with benthic foraminiferal carbon isotope gradients and/or the surface pore area percentages in foraminiferal tests (e.g., >15%) may provide semi-quantitative estimates of low BWO in past oceans (e.g., <∼50 μmol/kg). We present I/Ca records in five cores and a global compilation of multiproxy data, indicating that bottom waters were generally less-oxygenated during glacial periods, with low O2waters (<∼50 μmol/kg) occupying some parts of the Atlantic and Pacific Oceans. Water mass ventilation and circulation may have been important in deoxygenation of the glacial deep Pacific and South Atlantic, whereas enhanced remineralization of organic matter may have had a greater impact on reducing the oxygen content of the interior Atlantic Ocean.