The impact of abrupt deglacial climate variability on productivity and upwelling on the southwestern Iberian margin
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Date
2020-02-15
Publication Type
Journal Article
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Abstract
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 Bølling-Allerød (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 1 (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.
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Publication status
published
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Journal / series
Volume
230
Pages / Article No.
106139
Publisher
Elsevier
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Edition / version
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Date collected
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Subject
Paleoceanography; North Atlantic; Holocene; Deglaciation; Heinrich stadials; Nannofossils; IRD; Stable isotopes; AMOC
Organisational unit
03868 - Eglinton, Timothy I. (emeritus) / Eglinton, Timothy I. (emeritus)
Notes
Funding
175823 - TEMPORAL RELATIONSHIPS AMONG PROXY SIGNALS IN MARINE SEDIMENTS (TRAMPOLINE) (SNF)