Sea surface temperature variability in the central-western Mediterranean Sea during the last 2700 years: A multi-proxy and multi-record approach

This study presents the reconstructed evolution of sea surface conditions in the central-western Mediterranean Sea during the late Holocene (2700 years) from a set of multi-proxy records as measured on five short sediment cores from two sites north of Minorca (cores MINMC06 and HER-MC-MR3). Sea surface temperatures (SSTs) from alkenones and Globigerina bulloides Mgĝ€/ĝ€Ca ratios are combined with Î 18O measurements in order to reconstruct changes in the regional evaporation-precipitation (E-P) balance. We also revisit the G. bulloides Mgĝ€/ĝ€Ca-SST calibration and re-adjusted it based on a set of core-top measurements from the western Mediterranean Sea. Modern regional oceanographic data indicate that Globigerina bulloides Mgĝ€/ĝ€Ca is mainly controlled by seasonal spring SST conditions, related to the April-May primary productivity bloom in the region. In contrast, the alkenone-SST signal represents an integration of the annual signal. The construction of a robust chronological framework in the region allows for the synchronization of the different core sites and the construction of ĝ€œstackedĝ€? proxy records in order to identify the most significant climatic variability patterns. The warmest sustained period occurred during the Roman Period (RP), which was immediately followed by a general cooling trend interrupted by several centennial-scale oscillations. We propose that this general cooling trend could be controlled by changes in the annual mean insolation. Even though some particularly warm SST intervals took place during the Medieval Climate Anomaly (MCA), the Little Ice Age (LIA) was markedly unstable, with some very cold SST events mostly during its second half. Finally, proxy records for the last centuries suggest that relatively low E-P ratios and cold SSTs dominated during negative North Atlantic Oscillation (NAO) phases, although SSTs seem to present a positive connection with the Atlantic Multidecadal Oscillation (AMO) index. © Author(s) 2016.Cores MINMC06 were recovered by the HERMES 3 cruise in 2006 on R/V Thethys II and HER-MC-MR3 cores were collected by the HERMESIONE expedition onboard R/V Hespérides in 2009. This research was financially supported by OPERA (CTM2013-48639-C2-1-R) and Consolider-Redes (CTM2014-59111-REDC). We thank Generalitat de Catalunya Grups de Recerca Consolidats for grant 2009 SGR 1305 to GRC Geociències Marines. The Project of Strategic Interest NextData PNR 2011–2013 (www.nextdataproject.it) also collaborated in the financing. We are grateful to M. Guart (Dept. de Dinàmica de la Terra i de l’Oceà, Universitat de Barcelona), M. Romero, T. Padró and J. Perona (Serveis Cientifico-Tècnics, Universitat de Barcelona), J. M. Bruach (Departament de Física, Universitat Autònoma de Barcelona), and B. Hortelano, Y. Gonzalez-Quinteiro, and I. Fernández (Institut de Diagnosi Ambiental i Estudis de l’Aigua, CSIC, Barcelona) for their help with the laboratory work; to D. Amblàs for his collaboration with the artwork of maps; and to Paleoteam for the unconditional support. E. Garcia-Solsona, S. Giralt, and M. Blaauw are acknowledged for their help. We also acknowledge the guest editor and anonymous reviewers for their comments, which contributed to improving this paper. Belen Martrat acknowledges funding from CSIC-Ramon y Cajal post-doctoral programme RYC-2013-14073. Mercè Cisneros benefited from a fellowship of the University of Barcelona. Leopoldo D. Pena acknowledges support from the Ramón y Cajal programme (MINECO, Spain). Isabel Cacho thanks the ICREA-Academia programme from the Generalitat de Catalunya.Peer reviewe