Tracking orbital and suborbital climate variability in the westernmost Mediterranean over the past 13,000 years: New insights from paleoperspectives on marine productivity responses

This study presents a comprehensive analysis of a sediment record from the Western Alboran Basin (core
\nGP04PC), utilizing palynological and geochemical tools to investigate marine productivity responses to orbital
\nand suborbital climate variability over the past 13,000 years. High productivity during the Younger Dryas humid
\nphase (~12.4–11.7 ka) and the Holocene humidity optimum (~10.5–8.5 ka) was driven by increased local river
\ndischarges resulting from rapid mountain glaciers melting and enhanced regional precipitation. During the late
\nHolocene, frequent flood events linked to negative North Atlantic Oscillation (NAO) incursions potentially led to
\nmulticentennial-scale productivity increases. The findings indicate that periods characterized by wet regional
\nconditions and increased river run-off, influenced by orbital (e.g., insolation cycles) and suborbital factors (e.g.,
\nNAO and Atlantic Meridional Overturning Circulation changes), consistently enhanced marine productivity in
\nthe Western Alboran Basin. The study also reveals that the current high productivity and carbon export in the
\nWestern Alboran Basin are maintained by active upwelling and downwelling systems driven by a persistent
\npositive NAO phase following the southward migration of the Intertropical Convergence Zone (ITCZ) that
\noccurred around 6.5 ka. Furthermore, geochemical proxies support a strong detrital influence on trace metal
\nconcentrations, including barium (Ba), in deep Western Alboran sediments during the Holocene. This limits the
\nuse of Ba/Al ratios for accurately reconstructing productivity changes and highlights the importance of dinocyst
\nanalysis as a complementary tool for robust marine productivity reconstructions in this region. These observations
\nprovide valuable paleoperspectives on marine ecosystem responses to climate variability, contributing to
\nthe development of robust long-term productivity models essential for adapting to ongoing environmental
\nchanges in the region, and demonstrating the strong influence of North Atlantic climate and ocean dynamics on
\ncentennial-scale productivity oscillations in this region.