The impact of abrupt deglacial climate variability on productivity and upwelling on the southwestern Iberian margin
The impact of abrupt deglacial climate variability on productivity and upwelling on the southwestern Iberian margin
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DOI：
10.1016/j.quascirev.2019.106139
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发表时间：
2020-02-15
影响因子：
4
通讯作者：
Eglinton, Timothy I.
中科院分区：
文献类型：
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作者：
Ausin, Blanca;Hodell, David A.;Eglinton, Timothy I.
这项研究结合了超微化石丰度、氧和碳稳定同位素、岩心扫描X射线荧光(XRF)和冰排碎屑(IRD)的高分辨率记录，以评估伊比利亚西南部边缘最后一次冰川消融期间发生的古海洋学变化。我们的结果揭示了浮游生物生产力、中线深度和上升流现象的平行百年尺度振荡，这是以前没有观察到的，可以通过冰山融化水的到来、冰山诱导的湍流条件、SST变化和河流排放来解释。在千年时间尺度上，末次冰盛期(LGM)和波林-艾勒罗德(B/A)具有较高的初级生产力(PP)、较浅的中线和上升流发生/活跃。相反的情况(即生产力降低、中线加深和上升减弱/消失)与寒冷时期有关，例如海因里希体育场2和I(HS2和HS1)和年轻仙女座(YD)。这种古生产力的变化归因于与北大西洋大洋环流相关的热锋在纬度上的迁移，以及大西洋子午线翻转环流(AMOC)强度的振荡。全新世中高PP是由于现代季节性地表水文的发展，伊比利亚极地向流(IPC)和季节性风生上升流更为持久。(C)2020作者。爱思唯尔有限公司出版。
This study combines high-resolution records of nannofossil abundances, oxygen and carbon stable isotopes, core scanning X-ray fluorescence (XRF), and ice rafted debris (IRD) to assess the paleoceanographic changes that occurred during the last deglaciation on the SW Iberian Margin. Our results reveal parallel centennial-scale oscillations in coccolithophore productivity, nutricline depth and upwelling phenomena not previously observed, explained by means of arrival of iceberg-melting waters, iceberg-induced turbulent conditions, SST changes and riverine discharges. On millennial time-scales, higher primary productivity (PP), shallower nutricline, and upwelling occurrence/invigoration are observed for the Last Glacial Maximum (LGM) and Bolling-Allerod (B/A). The opposite scenario (i.e., lower productivity, deeper nutricline and upwelling weakening/absence) is linked to cold spells such as Heinrich Stadials 2 and I (HS2 and HS1) and the Younger Dryas (YD). Such paleoproductivity variations are attributed to latitudinal migrations of the thermal fronts associated with oceanic gyres in the North Atlantic, in parallel to oscillations in the strength of the Atlantic Meridional Overturning Circulation (AMOC). Moderate-to-high PP during the Holocene is ascribed to the development of the modern seasonal surface hydrography, with a more persistent Iberian Poleward Current (IPC) and seasonal wind-induced upwelling. (C) 2020 The Authors. Published by Elsevier Ltd.