The impact of abrupt deglacial climate variability on productivity and upwelling on the southwestern Iberian margin

Ausín, Blanca and Hodell, David A. and Cutmore, Anna and Eglinton, Timothy I. (2020) The impact of abrupt deglacial climate variability on productivity and upwelling on the southwestern Iberian margin. Quaternary Science Reviews, 230. p. 106139. ISSN 02773791 DOI https://doi.org/10.1016/j.quascirev.2019.106139

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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.

Item Type:	Article
Uncontrolled Keywords:	2019AREP; IA76
Subjects:	01 - Climate Change and Earth-Ocean Atmosphere Systems
Divisions:	02 - Geodynamics, Geophysics and Tectonics 07 - Gold Open Access
Journal or Publication Title:	Quaternary Science Reviews
Volume:	230
Page Range:	p. 106139
Identification Number:	https://doi.org/10.1016/j.quascirev.2019.106139
Depositing User:	Sarah Humbert
Date Deposited:	03 Mar 2020 18:17
Last Modified:	03 Mar 2020 18:17
URI:	http://eprints.esc.cam.ac.uk/id/eprint/4636

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