Late Glacial to Holocene radiocarbon constraints on North Pacific Intermediate Water ventilation and deglacial atmospheric CO2 sources
Late Glacial to Holocene radiocarbon constraints on North Pacific Intermediate Water ventilation and deglacial atmospheric CO2 sources
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DOI：
10.1016/j.epsl.2014.04.004
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发表时间：
2014-07-01
影响因子：
5.3
通讯作者：
Xuan, C.
中科院分区：
文献类型：
--
作者：
Davies-Walczak, Maureen;Mix, A. C.;Xuan, C.
放射性碳重建过去的海洋通风率限制海洋源和汇的CO2和地下缺氧的机制。在这里，来自阿拉斯加东南部682米深的沉积物岩心中共存的底栖有孔虫和浮游有孔虫中的C-14记录了过去类似于17，000年的古通风。一个年表的基础上校准的南极有孔虫的日期，与独立的陆地区域冰川退缩的日期一致，产生冰消投影年龄适度大于全新世，这表明相对有限的通风。观测到的全新世增加的明显通风在中间深度跟踪白令海峡的淹没之间类似于11,800和13,200年前，这表明大陆架的洪水和出口低盐度的表面沃茨北极增强中层水形成在北太平洋。底栖-浮游生物放射性碳年龄梯度的突然增加，意味着深海和中层沃茨中深海放射性碳的均一化，与冰川消退期间大气CO2快速上升和大气Delta C-14耗尽的两个事件中较年轻的事件相一致（类似于11，500 - 13，000年前），这表明北太平洋是冰消过渡后半期海洋CO2向大气排放的可能途径。(C)2014爱思唯尔有限公司版权所有。
Radiocarbon reconstructions of past ocean ventilation rates constrain oceanic sources and sinks of CO2 and mechanisms of subsurface hypoxia. Here, C-14 in coexisting benthic and planktonic foraminifera from a sediment core 682 m deep off Southeast Alaska documents paleoventilation over the past similar to 17,000 years. A chronology based on calibrated planktonic foraminiferal dates, consistent with independent terrestrial dates for regional glacial retreat, yields deglacial projection ages moderately greater than those of the Holocene, suggesting comparatively limited ventilation. The observed Holocene increase of apparent ventilation at intermediate depths tracks inundation of the Bering Strait between similar to 11,800 and 13,200 years ago, suggesting that flooding of continental shelves and export of low-salinity surface waters to the Arctic enhanced intermediate water formation in the North Pacific. An abrupt increase in the benthic-planktonic radiocarbon age gradient, implying homogenization of abyssal radiocarbon in deep and intermediate waters, aligns with the younger of two episodes of rapid rise of atmospheric CO2 and depletion of atmospheric Delta C-14 during deglaciation (similar to 11,500-13,000 years ago), suggesting the North Pacific as a possible pathway for venting of oceanic CO2 to the atmosphere during the second half of the deglacial transition. (C) 2014 Elsevier B.V. All rights reserved.