Sea surface temperature dynamics in the Ligurian Sea during the last 27.4 ka. Disentangling continental, Atlantic and ecological signals of the Globigerina bulloides Mg/Ca-based SST record

A new high-resolution Sea Surface Temperature (SST) record from the Ligurian Sea covering the last 27.4 ka was reconstructed using Mg/Ca ratios measured on Globigerina bulloides. It represents the first continuous Mg/Cabased SST reconstruction for this sector and provides a benchmark for assessing regional climate variability across major late Quaternary transitions. The record, compared with Mg/Ca-derived SSTs record from the Alboran and Balearic Seas, aligns at broader timescales with coherent SST trends associated with three major climatic phases: i) the glacial interval (27.4-14.7 ka cal BP), characterized by overall low SSTs and millennial-scale variability with pronounced cooling during Heinrich stadials; ii) the deglacial phase (14.7-11.7 ka cal BP), marked by an abrupt warming interrupted by short-lived cooling events; iii) the Holocene (11.7 ka cal BP-present), characterized by generally warmer conditions and reduced variability compared to the glacial interval. However, the SST record of the Ligurian Sea reflects a strong imprint of regional and continental forcings, superimposed on the broader Mediterranean signal. These include the influence of northerly wind systems, enhanced winter heat loss, and local oceanographic processes related to water mass formation and circulation, which modulate both the timing and amplitude of temperature changes. Our results demonstrate that Mediterranean SST variability cannot be interpreted as a uniform response to external forcing but instead reflects a mosaic of regional behaviors. The Ligurian Sea emerges as a key archive for capturing regionally driven climate signals and for improving our understanding of spatial heterogeneity in Mediterranean climate dynamics during the Late Quaternary.