Repeated Near-Collapse of the Pliocene Sea Surface Temperature Gradient in the North Atlantic

• Published in: Paleoceanography and Paleoclimatology
• Main Authors: Naafs, B. D. A., Voelker, A. H. L., Karas, C., Andersen, N., Sierro, F. J.
• Format: Article in Journal/Newspaper
• Language: English
• Published: American Geophysical Union 2020
• Subjects: Pliocene; North Atlantic; Biomarker; Sea surface temperature; IODP; Alkenone
• Online Access: https://doi.org/10.1029/2020PA003905; https://repositorio.uchile.cl/handle/2250/175740

Sea surface temperature (SST) is used to infer past changes in the state of the climate system. Here we use a combination of newly generated and published organic paleothermometer records, together with novel high-resolution benthic foraminiferal delta O-18 stratigraphy, from four sites in the midlatitude North Atlantic (41-58 degrees N) to reconstruct the long-term evolution of the latitudinal SST gradient during the Pliocene and early Pleistocene (4.0 to 2.4 Myr), the last time atmospheric CO2 reached concentrations above 400 ppmv. We demonstrate that the latitudinal SST gradient in the North Atlantic nearly collapsed twice during this period. We conclude that the latitudinal SST gradient in the midlatitude North Atlantic has two end-members: a maximum as existing at present and a minimum that existed during certain periods of the (late) Pliocene. Our results suggest that the 400-ppmv Pliocene world was more dynamic than currently thought. Netherlands Organization for Scientific Research (NWO) Royal Society Tata University Research Fellowship Portuguese Foundation for Science and Technology IF/01500/2014 UID/Multi/04326/2019 German Research Foundation (DFG) KA3461/1-2 Spanish National Science Agency RTI2018-099489-B-I00 ANID Millennium Science Initiative/Millennium Nucleus Paleoclimate