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The early–middle pleistocene transition in the gulf of Cadiz (NE Atlantic) – an interplay between subtropical gyre and extremely cold surface waters

2025-05-20Journal article Open access
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dc.contributor.authorMega, Aline
dc.contributor.authorRodrigues, Teresa
dc.contributor.authorSalgueiro, Emilia
dc.contributor.authorPadilha, Mária
dc.contributor.authorKuhnert, Henning
dc.contributor.authorVoelker, Antje
dc.date.accessioned2025-07-03T12:22:13Z
dc.date.available2025-07-03T12:22:13Z
dc.date.issued2025-05-20
dc.description.abstractBesides the shift in dominant orbital cyclicity depicted in paleoclimate proxy records, the Mid-Pleistocene Transition or Early-Middle Pleistocene Transition (EMPT) was linked to a change in the deep thermohaline circulation. Those changes contributed to more intense and longer-lasting glacial periods and cooler sea surface temperatures (SSTs) during glacials. Within the Atlantic Ocean, the Iberian Margin is considered a key location to study climatic variations influenced by both high- and low-latitude processes. In this study we focus on IODP Site U1387 on the southern Portuguese margin to reconstruct surface water circulation changes and related plankton foraminifera ecosystems during the interval of Marine Isotope Stage (MIS) 28 to MIS 18 (1006-750 ka). Our planktonic foraminifera assemblages and SST reconstructions (foraminifera assemblages and U-37(K ') alkenone index) demonstrate warm, relative stable SST conditions during much of the interval due to persistent influence of subtropical gyre waters as indicated by the tropical-subtropical and Azores Current-related foraminifera species and the periods with dominant sinistral coiling direction of the species Globorotalia truncatulinoides. Maximum interglacial SSTs were up to 2 degrees C warmer than at present in both summer and winter, with the exception of interglacial MIS 23 with SSTs similar to 1.5 degrees C colder than in the other interglacials. Subsequent to the respective glacial inception, the relatively warm conditions were periodically interrupted by millennial-scale extreme cold events when polar species Neogloboquadrina pachyderma became abundant (> 30 %), and the SSTs, reconstructed from the foraminifera assemblage data, dropped below 10 degrees C in summer and 5 degrees C in winter, although some of those values might be overestimated. The most pronounced event, considering the amplitude of cooling and duration, occurred between 870 and 864 ka, marking the terminal stadial event of the MIS 22-MIS 21 transition (Termination X). Extreme cold events, always associated with the incursion of subpolar waters into the Gulf of Cadiz, mark all the terminal stadial events from Terminations XII to IX and the millennial-scale variability during the transitions to full glacial conditions, although the duration of the cooling varied greatly. The extreme cooling was only possible through migration of the subarctic front into the lower mid-latitudes as a consequence of cooling and freshening in the higher latitudes and the associated extreme reduction in the Atlantic Meridional Overturning Circulation. The amplitude of cooling, duration, and frequency of subpolar water incursions during MIS 24 to MIS 22 stands out, providing further evidence for the "900 ka event" being a key feature of the EMPT.eng
dc.description.sponsorshipMAR01/UIDP/04326/2020; POCI-01-0145-FEDER-022157;
dc.identifier.doi10.5194/cp-21-919-2025
dc.identifier.issn1814-9332
dc.identifier.urihttp://hdl.handle.net/10400.1/27346
dc.language.isoeng
dc.peerreviewedyes
dc.publisherCopernicus Publications
dc.relationSurface and Mediterranean Outflow Water Dynamics in the Gulf of Cadiz during the Pleistocene
dc.relationAlgarve Centre for Marine Sciences
dc.relationAlgarve Centre for Marine Sciences
dc.relationUnderstanding past short and long-term climate variations as guidelines for future climate change
dc.relationLA/P/0101/2020
dc.relation.ispartofClimate of the Past
dc.rights.urihttp://creativecommons.org/licenses/by/4.0/
dc.subjectContourite depositional system
dc.subjectGibraltar strait region
dc.subjectWestern iberian margin
dc.subjectNorth-atlantic
dc.subjectPlanktonic-foraminifera
dc.subjectGloborotalia-truncatulinoides
dc.subjectCooling events
dc.subjectIsotope stages
dc.subjectSea
dc.subjectTemperature
dc.titleThe early–middle pleistocene transition in the gulf of Cadiz (NE Atlantic) – an interplay between subtropical gyre and extremely cold surface waterseng
dc.typejournal article
dspace.entity.typePublication
oaire.awardTitleSurface and Mediterranean Outflow Water Dynamics in the Gulf of Cadiz during the Pleistocene
oaire.awardTitleAlgarve Centre for Marine Sciences
oaire.awardTitleAlgarve Centre for Marine Sciences
oaire.awardTitleUnderstanding past short and long-term climate variations as guidelines for future climate change
oaire.awardURIinfo:eu-repo/grantAgreement/FCT/3599-PPCDT/PTDC%2FMAR-PRO%2F3761%2F2012/PT
oaire.awardURIinfo:eu-repo/grantAgreement/FCT/6817 - DCRRNI ID/UIDB%2F04326%2F2020/PT
oaire.awardURIinfo:eu-repo/grantAgreement/FCT/6817 - DCRRNI ID/UIDP%2F04326%2F2020/PT
oaire.awardURIinfo:eu-repo/grantAgreement/FCT/Investigador FCT/IF%2F01500%2F2014%2FCP1251%2FCT0003/PT
oaire.citation.endPage939
oaire.citation.issue5
oaire.citation.startPage919
oaire.citation.titleClimate of the Past
oaire.citation.volume21
oaire.fundingStream3599-PPCDT
oaire.fundingStream6817 - DCRRNI ID
oaire.fundingStream6817 - DCRRNI ID
oaire.fundingStreamInvestigador FCT
oaire.versionhttp://purl.org/coar/version/c_970fb48d4fbd8a85
person.familyNameMega
person.familyNameRodrigues
person.familyNameSalgueiro
person.familyNameVoelker
person.givenNameAline
person.givenNameTeresa
person.givenNameEmilia
person.givenNameAntje
person.identifier2315310
person.identifier.ciencia-idEC18-2390-9594
person.identifier.ciencia-id3B10-07FD-161C
person.identifier.ciencia-idC11E-D8E6-CDFA
person.identifier.orcid0000-0002-9386-2261
person.identifier.orcid0000-0001-7811-7506
person.identifier.orcid0000-0003-1000-2977
person.identifier.orcid0000-0001-6465-6023
person.identifier.ridG-2912-2013
person.identifier.ridG-1019-2013
person.identifier.ridC-5427-2012
person.identifier.scopus-author-id7004330274
person.identifier.scopus-author-id23486371200
person.identifier.scopus-author-id8784446000
project.funder.identifierhttp://doi.org/10.13039/501100001871
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project.funder.identifierhttp://doi.org/10.13039/501100001871
project.funder.nameFundação para a Ciência e a Tecnologia
project.funder.nameFundação para a Ciência e a Tecnologia
project.funder.nameFundação para a Ciência e a Tecnologia
project.funder.nameFundação para a Ciência e a Tecnologia
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