Changes in latitudinal sea surface temperature gradients along the Southern Chilean margin since the last glacial. (15th August 2018)

• Record Type: Journal Article
• Authors: Haddam, Naoufel Abdeldjalyl; Siani, Giuseppe; Michel, Elisabeth; Kaiser, Jérôme; Lamy, Frank; Duchamp-Alphonse, Stéphanie; Hefter, Jens; Braconnot, Pascale; Dewilde, Fabien; Isgüder, Gülay; Tisnerat-Laborde, Nadine; Thil, François; Durand, Nicolas; Kissel, Catherine
• Is Part Of: Quaternary science reviews. Volume 194(2018)
• Page Start: 62
• Page End: 76
• Publication Date: 2018-08-15
• Subjects: Sea surface temperature latitudinal gradient -- Subtropical front -- Bipolar seesaw -- Sea surface salinity -- Patagonian ice sheet melting -- Last 22 kyr cal. BP; Geology, Stratigraphic -- Quaternary -- Periodicals; Stratigraphie -- Quaternaire -- Périodiques; 551.79
• DOI: 10.1016/j.quascirev.2018.06.023
• Languages: English
• ISSNs: 0277-3791

Abstract

Abstract: The comparison between different climate model simulations of water hosing experiments under glacial conditions points toward diverging responses in Sea Surface Temperature changes (SST) especially in the Southeast Pacific (SEP). This suggests that reconstituting the latitudinal SST gradient in the SEP is a critical parameter for a better understanding of the mechanisms behind the abrupt climatic events since the last glacial period. Here we present, high-resolution records of SST, using planktonic foraminiferal assemblages and alkenone temperature reconstructions and stable oxygen and carbon isotopes from three deep-sea sediment cores along a latitudinal transect off the southern Chilean coast. This allowed us to reconstruct the variations of the latitudinal SST gradient and the Subtropical Front movements in the SEP. The SST results suggest a clear Antarctic timing consistent with the bipolar seesaw control, especially during the late glacial and the deglaciation. Our records do not suggest a complete oceanic heat transfer signal, highlighting the implication of an atmospheric component in the heat transfers between the two hemispheres, controlled by the latitudinal movements of the intertropical convergence zone in the Atlantic and the associated weaker South Pacific westerly split jet. Furthermore, our records indicate variable conditions during the Holocene, and also emphasize the influence of local fresh water inputs from the Patagonian ice sheet and/or precipitation on the SST fresh water input estimates along the Chilean margin (North and South of 49° S) from the onset of the deglaciation until 8 kyr cal. BP. Highlights: Sea surface temperature reconstruction since the last 22 kyr (Southeast Pacific). Temperature were reconstructed using planktonic foraminifera assemblage counts and alkenones data. Melting of Patagonian Ice-Sheets influenced coastal temperatures. Latitudinal temperature gradient shows the migrations of the subtropical front. The movements of the subtropical front respond to the bipolar seesaw.