Department of Earth Science, University of Cambridge, Cambridge, UK.
Science. 2022 Aug 5;377(6606):654-659. doi: 10.1126/science.abj7761. Epub 2022 Aug 4.
The oxygen concentrations of oceanic deep-water and atmospheric carbon dioxide (CO) are intrinsically linked through organic carbon remineralization and storage as dissolved inorganic carbon in the deep sea. We present a high-resolution reconstruction of relative changes in oxygen concentration in the deep North Atlantic for the past 1.5 million years using the carbon isotope gradient between epifaunal and infaunal benthic foraminifera species as a proxy for paleo-oxygen. We report a significant (>40 micromole per kilogram) reduction in glacial Atlantic deep-water oxygenation at ~960 thousand to 900 thousand years ago that coincided with increased continental ice volume and a major change in ocean thermohaline circulation. Paleo-oxygen results support a scenario of decreasing deep-water oxygen concentrations, increased respired carbon storage, and a reduction in glacial CO across the Middle Pleistocene Transition.
海洋深水中的氧气浓度与大气二氧化碳（CO）浓度通过有机碳的再矿化和以溶解无机碳的形式在深海中储存而内在地联系在一起。我们利用外生和内生底栖有孔虫种之间的碳同位素梯度作为古氧的替代指标，提供了过去 150 万年北大西洋深海中氧浓度相对变化的高分辨率重建。我们报告说，在约 96 万至 90 万年前的冰川大西洋深海中氧气明显减少（>40 微摩尔/千克），这与大陆冰量增加和海洋热盐环流的重大变化相吻合。古氧结果支持了一种情景，即在中更新世过渡期，深层水的氧浓度降低，呼吸碳的储存增加，以及冰川 CO 的减少。
