Sensitivity of the Western Mediterranean Sea to Holocene climate variability Isabel Cacho 1, Gemma Herrera 1, Jaume Frigola 1, Miquel Canals 1 & Ana Moreno 2 1 GRC Geociències Marines,Universitat de Barcelona 2 Instituto Pirenaico de Ecología – CSIC - Zaragoza CLIVAR seminar : Clima en España, Pasado, Presente y futuro (Madrid, febrero 2009) 1/16

Outline CLIVAR seminar : Clima en España, Pasado, Presente y futuro (Madrid, febrero 2009) 1.Sensitivity of the W Mediterranean surface and deep waters to past rapid climate variability 2.Climate instability/stability along the Holocene 3.Response of the W Mediterranean to Holocene millennial-centennial climate variability 4.Summary and future lines 2/16

Past climate variability in Greenland GISP2 Dansgaard- Oeschger Cycles Holocene CLIVAR seminar : Clima en España, Pasado, Presente y futuro (Madrid, febrero 2009) 3/16 Warm Cold Age (ka BP) Dansgaard et al. (1993)

Greenland-Mediterranean connections CLIVAR seminar : Clima en España, Pasado, Presente y futuro (Madrid, febrero 2009) 4/16

Age (cal. kyr B.P.) D-O variability in Mediterranean SST H1H2H3H4H5YD (%) Cacho et al (Paleoceanography) GISP2 Greenland GISP2 Dome (Greenland) Emiliania huxleyi MD Alboran Sea Age (cal. kyr B.P.) Alkenone SST (°C) ice  18 O (‰) N. pachyderma (s) CLIVAR seminar : Clima en España, Pasado, Presente y futuro (Madrid, febrero 2009) 5/16

D-O variability in WMDW? CLIVAR seminar : Clima en España, Pasado, Presente y futuro (Madrid, febrero 2009) 6/16

D-O variability in WMDW H2H1H3H5H4YD GISP2  18 O (‰)  18 O (‰)  13 C (‰) Age cal. Kyr B.P. Polar Circulation Index GISP2 Cacho et al., 2001 (Earth Planet. Sc. L.); Cacho et al., 2006 (QSR) Colder/saltier WMDW More oxygenated WMDW More intense atmospheric circulation CLIVAR seminar : Clima en España, Pasado, Presente y futuro (Madrid, febrero 2009) 7/16

Modes of WMDW variability Interstadial Mode: Pour ventilated WMDW Stadial Mode: Well ventilated WMDW CLIVAR seminar : Clima en España, Pasado, Presente y futuro (Madrid, febrero 2009) Colder/saltier WMDW More oxygenated WMDW MD (dark) and MD (light) H2H1H3H5H4YD  13 C (‰)  18 O (‰) Cacho et al., 2001 (EPSL) and 2006 (QSR) Sierro et al., 2005 (Paleoc.) 8/16

Holocene Atmospheric Variability CLIVAR seminar : Clima en España, Pasado, Presente y futuro (Madrid, febrero 2009) Mayewski et al (Quat. Res.) 9/16

Holocene variability in North Atlantic Ocean Holocene ice rafted events: fresh volcanic glass and hematite-stained grains Bond et al., (1997) CLIVAR seminar : Clima en España, Pasado, Presente y futuro (Madrid, febrero 2009) 10/16

Viking expansion during the MWP CLIVAR seminar : Clima en España, Pasado, Presente y futuro (Madrid, febrero 2009) 11/16

C 37 Alkenones (ng/g) Alkenone SST (ºC)  18 O (‰) Age (cal. Ky BP) GISP2 - Greenland MD Alboran 8.2 event Cacho et al., 2002 (JMS) Rogerson et al 2008 (G3) Last ORL CLIVAR seminar : Clima en España, Pasado, Presente y futuro (Madrid, febrero 2009) Holocene Variability in the Mediterranean (I) 12/16

GISP2 UP10 (%) Si/Al  18 O (‰) G. bulloides SST (ºC)  18 O (‰) ice  18 O (‰) ice Age (ka BP) Alboran Sea Menorca Rise Alboran SST Frigola et al., 2007 (Paleoceanography) & 2008 (Quarter. Inter.) CLIVAR seminar : Clima en España, Pasado, Presente y futuro (Madrid, febrero 2009) Fastest Deep water current Stronger WMDW overturning Holocene Variability in the Mediterranean (II) 13/16

Age (ka BP) Menorca SST ? ? UP10 (%) Si/Al SST (ºC) Frigola et al., 2007 (Paleoceanography); Herrera unpublished CLIVAR seminar : Clima en España, Pasado, Presente y futuro (Madrid, febrero 2009) Holocene Variability in the Mediterranean (III) Fastest Deep water current Stronger WMDW overturning 14/16

CLIVAR seminar : Clima en España, Pasado, Presente y futuro (Madrid, febrero 2009) Potential causes of Holocene Variability in the Mediterranean Could a persistent/intense + NAO state cause Holocene events of enhance WMDW overturning? 15/16

1. Mediterranean Sea has been very sensitive to past rapid climate variability, inducing changes in both surface and deep water masses 2. Western Mediterranean Deep Water cell was very sensitive to Holocene climate variability: - Recurrent events of faster deep water currents - Parallel cooling of surface layer (1.5-3ºC) Summary Future Lines 1. Precise characterization of the Holocene variability: reproducing present records at different sites and with different proxies and with improved timing constrain. 2. Reconstruct water properties at deep and also intermediate water layer.

Acknowledgments Consolider GRACCIE: Multidisciplinary Research Consortium on GRadual and Abrupt Climate Changes, and their Impacts on the Environment The Comer Science & Education Foundation (USA) CLIVAR seminar : Clima en España, Pasado, Presente y futuro (Madrid, febrero 2009) extra

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