Asymmetric response of the subtropical western South Atlantic thermocline to the Dansgaard-Oeschger events of Marine Isotope Stages 5 and 3

Autor(es)

Santos, Thiago P. ^[1] ; Ballalai, Joao M. ^[1] ; Franco, Daniel R. ^[2] ; Oliveira, Romulo R. ^[2] ; Lessa, Douglas O. ^[1] ; Venancio, Igor M. ^[3] ; Chiessi, Cristiano M. ^[4] ; Kuhnert, Henning ^[5] ; Johnstone, Heather ^[5] ; Albuquerque, Ana Luiza S. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Fed Fluminense, Programa Geociencias Geoquim, Niteroi, RJ - Brazil

^[2] Observ Nacl, Coordenacao Geofis, Rio De Janeiro - Brazil

^[3] Natl Inst Space Res INPE, Ctr Weather Forecasting & Climate Studies CPTEC, Cachoeira Paulista - Brazil

^[4] Univ Sao Paulo, Escola Artes Ciencias & Humanidades, Sao Paulo - Brazil

^[5] Univ Bremen, MARUM Ctr Marine Environm Sci, Bremen - Germany

• Tipo de documento: Artigo Científico
• Fonte: QUATERNARY SCIENCE REVIEWS; v. 237, JUN 1 2020.
• Citações Web of Science: 0

Resumo

The last glacial period (116-11.7 ka BP) was an interval characterized by a sequence of abrupt millennial-scale events well documented in Greenland and Antarctica ice-cores. Throughout this period, Greenland cold stadials were accompanied by warm conditions in the thermocline to intermediate waters of the Atlantic Ocean that may have played a role in both the basal melting of ice shelves and the rapid atmospheric warming during the onset of warm interstadials. Climate model simulations indicated an accentuated response of the subtropical western South Atlantic thermocline to the disturbances in the Atlantic circulation. Such works encourage investigations upon thermocline/deep-dwelling planktic foraminifera in this region; however, a study with this aim was not performed. Here we present a paleoceanographic reconstruction from the subtropical western South Atlantic based on the thermocline planktic foraminifera Globorotalia inflata. Our high-resolution delta O-18 record for the last glacial period presents a millennial-scale variability that strongly resembles the structure of the Greenland Dansgaard-Oeschger cycles during Marine Isotope Stage (MIS) 5. During MIS 3, this millennial-scale variability is absent or considerably dampened. Mg/Ca-derived temperature and seawater delta O-18 corrected for ice-volume for the MIS 5 interval demonstrate that the region was warmer and saltier (colder and fresher) during early-glacial stadials (interstadials). Our data suggest a reorganization of the northward heat transport throughout the last glacial, in which regions as far south as 24 degrees S acted as heat reservoirs in periods of weakened Atlantic Meridional Overturning Circulation during MIS 5 but not necessarily (or only marginally) during MIS 3. (C) 2020 Elsevier Ltd. All rights reserved. (AU)

• Processo FAPESP: 18/15123-4 - Perspectivas pretéritas sobre limiares críticos do sistema climático: a Floresta Amazônica e a célula de revolvimento meridional do Atlântico (PPTEAM)
• Beneficiário: Cristiano Mazur Chiessi
• Modalidade de apoio: Auxílio à Pesquisa - Programa de Pesquisa sobre Mudanças Climáticas Globais - Jovens Pesquisadores - Fase 2