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

The Novel Hydroxylated Tetraether Index RI‐OH′ as a Sea Surface Temperature Proxy for the 160‐45 ka BP Period Off the Iberian Margin

“…Such a contrast is also relevant for RI‐OH to a lesser extent (Figures and ). During Heinrich events H6‐H1, primary productivity dropped and the nutricline deepened (e.g., Ausín et al., 2020; Incarbona et al., 2010; Pailler & Bard, 2002). Similarly, biomarker concentrations dropped during all MIS 5 stadials (Figures 3 and ) which Eynaud et al.…”

“…During the last glacial cycle, the surface hydrology was generally similar to the modern one, with a stronger summer upwelling (e.g., Voelker & de Abreu, 2011, and references therein; Voelker et al., 2009). However, during Heinrich events, the Polar Front reached the southern Iberian Margin (Bard, Arnold, Maurice, et al., 1987; Eynaud et al., 2009), leading to a potential cessation of the upwelling (Ausín et al., 2020; Incarbona et al., 2010; Pailler & Bard, 2002) and hydrological conditions similar to modern winter ones (Eynaud et al., 2009).…”

Control Mechanisms of Primary Productivity Revealed by Calcareous Nannoplankton From Marine Isotope Stages 12 to 9 at the Shackleton Site (IODP Site U1385)

“…Addressing this question requires direct comparison of primary productivity records with those of continental and oceanic conditions derived from the same marine sequence, allowing a better evaluation of the interactions between the atmosphere, ocean and land systems, and modeling validation (e.g., Hernandez et al., 2021). Furthermore, extreme episodes of iceberg calving, such as the Heinrich events of the las glacial cycle or the Heinrich stadial‐ type events up to the middle Pleistocene, when subpolar fronts experimented marked southward displacements down to 40°N (e.g., Eynaud et al., 2009; Naughton et al., 2009; Rodrigues et al., 2011), are known to lead coastal upwelling weakening or cessation by the southward incursion of iceberg‐melting waters (e.g., Ausín et al., 2020; Voelker et al., 2010).…”

Oldest Dryas hydroclimate reorganization in the eastern Iberian Peninsula after the iceberg discharges of Heinrich Event 1

“…Discarding other sources of freshwater fluxes, such as hypothetical enhanced river runoffs that are unlikely during this time, the peaks of low δ 18 O of MAAT are presumably explained by the entrance of freshened Atlantic water. Previous records from the Mediterranean Sea suggest the arrival of such fresh water during HE-1 (Sierro et al, 2005) and few millennia before with enhanced fluvial discharges from northern European glaciers (Bazzicalupo et al, 2018; Ausín et al, 2020). Likewise, taking into account the main assumption of δ 18 O controlled by hydrological availability, any hypothetical increase in humid conditions at that time is unlikely to explain such δ 18 O excursion, since it cannot be supported by trace-metal ratios or any other hydrological proxy.…”

“…Oldest Dryas hydroclimate reorganization in the eastern Iberian Peninsula enhanced fluvial discharges from northern European glaciers (Bazzicalupo et al, 2018;Ausín et al, 2020). Likewise, taking into account the main assumption of δ 18 O controlled by hydrological availability, any hypothetical increase in humid conditions at that time is unlikely to explain such δ 18 O excursion, since it cannot be supported by trace-metal ratios or any other hydrological proxy.…”