Paleohydrological dynamics in the Western Mediterranean during the last glacial cycle

Garcia-Alix, A. , Camuera, J., Ramos-Roman, M. J., Toney, J. L. , Sachse, D., Schefuß, E., Jimenez-Epejo, F. J., Lopez-Aviles, A., Anderson, R. S. and Yanes, Y. (2021) Paleohydrological dynamics in the Western Mediterranean during the last glacial cycle. Global and Planetary Change, 202, 103527. (doi: 10.1016/j.gloplacha.2021.103527)

Abstract

The transitional regions between the low and high latitudes of the Northern Hemisphere are highly vulnerable to future climate change yet most of the current climate models usually diverge in their projections. To better understand the dynamics in these regions, the reconstruction of past hydrological fluctuations and precipitation patterns is of paramount importance to accurately constrain present and future climate scenarios. In this study, we investigated paleohydrological dynamics in the western Mediterranean region, a transitional zone between low-mid latitudes and Atlantic - Mediterranean realms. We reconstruct precipitation and moisture source changes during the last ~35 ka in order to propose the potential mechanisms driving these oscillations. To do so, we use hydrogen isotopes from sedimentary leaf waxes, more specifically the C31 n-alkane homologue, and a precipitation proxy based on previously published pollen data from a sedimentary core (Padul-15-05) in southern Iberia (Padul wetland ~37° N). With this combination we disentangle the coupled effect of precipitation amount and source on the hydrogen isotopic signature of the studied C31 n-alkane record. Our results show three main periods characterized by different precipitation patterns. Low precipitation, mainly linked to a significant contribution from an isotopically-enriched Mediterranean precipitation source, occurred from ~30 to ~15.5 ka BP and during the last ~5 ka, whereas enhanced precipitation with a predominant isotopically-depleted Atlantic precipitation source prevailed from ~15.5 to ~5 ka BP. This latter stage is here defined as the Western Mediterranean Humid Period (WMHP). In addition, some occasional millennial-scale opposite precipitation patterns can be observed during these climatically distinct periods. These changes in the source of precipitation were likely coupled to a shift in the main rainy season from winter, when Atlantic precipitation prevailed, to late winter-early spring, when the contribution of Mediterranean moisture is higher. Comparison between the studied mid-latitude terrestrial Padul-15-05 core and a low-latitude marine record offshore of northwestern Africa shows clear long-term synchronous responses of both western Mediterranean precipitation and western African monsoon systems to northern Hemisphere atmospheric dynamics, ultimately controlled by orbital forcing and ice-sheets fluctuations.

• Item Type: Articles
• Additional Information: This study was supported by the project B-RNM-144-UGR18 of the action “Proyectos I+D+i del Programa Operativo FEDER 2018 - Junta de Andalucía-UGR”, the projects CGL2013-47038-R and CGL2017-85415-R, of the “Ministerio de Economía y Competitividad of Spain and Fondo Europeo de Desarrollo Regional FEDER”, and the research group RNM-190 (Junta de Andalucía). A.G.-A. was also supported by a Marie Curie Intra-European Fellowship of the 7th Framework Programme for Research, Technological Development and Demonstration of the vEuropean Commission (NAOSIPUK. Grant Number: PIEF-GA-2012-623027) and by a Ramón y Cajal Fellowship RYC-2015-18966 of the Spanish Government (Ministerio de Economía y Competividad). J.C. acknowledges the postdoctoral funding provided by the Academy of Finland (project number 316702). J.L.T. hosted the NAOSIPUK project (PIEF-GA-2012-623027) at the University of Glasgow. A.L.-A PhD is funded by BES-2018-084293 (Ministerio de Economía y Competividad). M.J.R.R. acknowledges the postdoctoral funding by the European Research Council (ERC-2017-ADG-788616). This study was supported by an ERC Consolidator Grant (STEEPclim) to D.S. (Grant Agreement No. 647035). E.S. is supported by the DFG Cluster of Excellence 2077 ›The Ocean Floor – Earth's Uncharted Interface‹ at MARUM. We thank Ralph Kreutz for analytical support.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Garcia-Alix Daroca, Dr Antonio and Toney, Professor Jaime
• Authors: Garcia-Alix, A., Camuera, J., Ramos-Roman, M. J., Toney, J. L., Sachse, D., Schefuß, E., Jimenez-Epejo, F. J., Lopez-Aviles, A., Anderson, R. S., and Yanes, Y.
• College/School: College of Science and Engineering > School of Geographical and Earth Sciences
• Journal Name: Global and Planetary Change
• Publisher: Elsevier
• ISSN: 0921-8181
• ISSN (Online): 1872-6364
• Published Online: 25 May 2021
• Copyright Holders: Copyright © 2021 The Authors
• First Published: First published in Global and Planetary Change 202:103527
• Publisher Policy: Reproduced under a Creative Commons Licence