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

Nowadays, primary productivity variations at the SW Iberian Margin (IbM) are primarily controlled by wind-driven upwelling. Thus, major changes in atmospheric circulation and wind regimes between Marine Isotope Stages (MIS) 12 9 could have driven substantial phytoplankton which remains poorly understood. We present a high-resolution calcareous nannofossil record from Shackleton Site Integrated Ocean Discovery Program U1385 that allow assessment of changing surface conditions on orbital suborbital timescales over IbM. These records directly compared integrated with terrestrial – Mediterranean forest pollen marine benthic planktic oxygen stable isotopes (?18O), alkenone concentration [C37], Uk´37-Sea Surface Temperature % C37:4 proxy U1385. Our results indicate intra-interglacial increase together intensification Azores anticyclonic high-pressure cell beyond summer suggests two-phase upwelling behavior during full interglacial MIS 11c (?420–397 ka), potentially drived NAO-like variability. Primary is largely enhanced inception glacial 10 early (?392–356 linked to intensified associated processes period strengthened circulation. In agreement observed Heinrich events last cycle, reductions abrupt cold episodes, including Heinrich-type (Ht) 4 1 (?436, 392, 384 339 ka) Terminations V IV, seems be result halocline formation induced meltwater arrival, reducing regional upward nutrient transference.