Portuguese Margin MIS6 foraminiferal isotope and palynology data Margari, V.; Skinner, L.C.; Tzedakis, P.C.; Ganopolski, A.; Vautravers, M.J.; Shackleton, N.J. Margari, V. Skinner, L.C. Tzedakis, P.C. Ganopolski, A. Vautravers, M.J. Shackleton, N.J. Heinrich Events Meridional Overturning Circulation (MOC) earth science/paleoclimate/paleoceanography (depth,null,null,meter,null,paleoceanography,null,null,N,null) earth science/paleoclimate/paleoceanography (age,null,null,calendar kiloyear before present,null,paleoceanography,null,null,N,null) earth science/paleoclimate/paleoceanography (delta 18O,benthic foraminifer,null,per mil,null,paleoceanography,averaged,null,N,null) earth science/paleoclimate/paleoceanography (delta 18O,Globigerina bulloides,null,per mil,null,paleoceanography,null,null,N,null) earth science/paleoclimate/paleocean earth science/paleoclimate/paleocean earth science/paleoclimate/paleocean (MD01-2444>LATITUDE 37.561333>LONGITUDE -10.142167) During the last glacial period, iceberg discharges into the North Atlantic disrupted the meridional overturning circulation, leading to cooling in the Northern Hemisphere and warming in Antarctica. This asymmetric response can be explained by a bipolar see-saw mechanism, whereby changes in the strength of the meridional overturning circulation lead to changes in the interhemispheric heat transport. It is unclear, however, to what extent the response of the overturning circulation is a function of freshwater flux and boundary climate conditions. Here we use foraminiferal isotope and pollen records from the Portuguese margin to reconstruct surface- and deep-water hydrography and atmospheric changes during the last and penultimate glacial periods. When we compare our records with temperature reconstructions from Antarctica, we find that the bipolar see-saw was a characteristic feature of both glacial periods. However, the comparison also underlines the dependence of the bipolar see-saw on background climate and magnitude of iceberg discharge. It also suggests that an intensified hydrological cycle may lead to a weaker overturning circulation with a smaller disruption threshold and extended North Atlantic stadial durations. STUDY NOTES: The following benthic species were analysed, and adjusted as indicated: Cibicidoides sp.: +0.51; Uvigerina peregrina and similar specimens: 0.0; Globobulimina affinis: -0.4; Cibicidoides wuellerstorfi, +0.64; Globocassidulina sp.: -0.1; Hoeglundina elegans: -0.7. MD01-2444 MIS3 isotope and faunal data in Vautravers and Shackleton, 2006. NCDC-Paleoclimatology https://www.ncdc.noaa.gov/data-access/paleoclimatology-data - Bauer Bruce Investigator : Margari, V. Investigator : Skinner, L.C. Investigator : Tzedakis, P.C. Investigator : Ganopolski, A. Investigator : Vautravers, M.J. Investigator : Shackleton, N.J. 2010-09-10 ONLINE Files online, ASCII https://www.ncdc.noaa.gov/paleo/study/9627 https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/margari2010/margari2010.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/margari2010/margari2010.txt English https://www.ncdc.noaa.gov/paleo/study/9627 https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/margari2010/margari2010.txt Margari, V., L.C. Skinner, P.C. Tzedakis, A. Ganopolski, M. Vautravers and N.J. Shackleton. 2010. The nature of millennial-scale climate variability during the past two glacial periods. Nature Geoscience 3, 127 - 131. START YEAR: 193287 cal yr BP * END YEAR: 136100 cal yr BP -10.142167 37.561333 -10.142167 37.561333