Holocene Climate variability in the Western Mediterranean Sea: an integrated oceanic and atmospheric perspective

• Main Author: Català i Caparrós, Albert
• Other Authors: Cacho Lascorz, Isabel, Pena González, Leopoldo David, Universitat de Barcelona. Departament de Dinàmica de la Terra i de l'Oceà
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: Universitat de Barcelona 2022
• Subjects: Paleoclimatologia; Paleoceanografia; Holocè; Isòtops radioactius en geologia; Paleoclimatology; Paleoceanography; Holocene; Radioisotopes in geology; Planktonic foraminifera
• Online Access: http://hdl.handle.net/2445/194761; http://hdl.handle.net/10803/687833

[eng] The Mediterranean region is very sensitive to modern climate variability. Located in a temperate subtropical climatic zone and surrounded almost entirely by large continental masses, the Mediterranean region climate and oceanography are largely controlled by the climatic variability of the subtropical and subpolar atmospheric systems. The western Mediterranean Sea exchanges seawater through the Strait of Gibraltar with the Atlantic Ocean, where inflowing surface waters from the Atlantic Ocean enter this region. In contrast, Mediterranean waters outflow into the Atlantic at depth, a net exchange of heat and salts that is very sensitive to present and past climatic changes. This thesis presents a new approach to studying and understanding past natural climatic variability of the Mediterranean region by analysing the changes in the ocean and the atmosphere during the Holocene. This thesis aims to improve our understanding of the mechanisms and climatic/oceanographic responses that have modulated the southern Iberian Peninsula climate during the last 11.700 years. In addition, relevant methodological advances in «state-of-the-art» geochemical tools are implemented here to study past hydrological changes and, for the first time, these methods are validated using a modern time series record in the Alboran Sea. This thesis has been built on four main key points: First, a new high-resolution deglacial and Holocene Sea Surface Temperature (SST) reconstruction is presented for the Alboran Sea (western Mediterranean), based on Mg/Ca ratios measured in the planktonic foraminifera Globigerina bulloides. This new SST record is evaluated by comparison with other Mg/Ca–SST records and previously published alkenone–SST reconstructions from the same region. The comparison shows a high degree of coherence between the different Mg/Ca–SST records but strong discrepancies compared to the alkenone– SST records. We argue that these discrepancies arise from differences in the sensitivity of the proxy–response to environmental ...