This paper documents the last 10 ka evolution of one of the key parameters of climate: sea-surface temperatures (SST) in the subpolar North Atlantic. We focus on the southern Bay of Biscay, a highly sensitive oceanographic area because of its strategic and nodal position regarding the dynamics of the North Atlantic subpolar and subtropical gyres. This site furthermore offers unique sedimentary environments characterized by exceptional accumulation rates, enabling the study of Holocene archives at (infra)centennial scales. Our results mainly derive from planktonic foraminiferal association analysis on two cores from the southern Landes plateau. These associations were used as quantitative tools (thanks to the Modern Analog Technique) to track past hydrographical changes. SST reconstructions were thus obtained at an unprecedented resolution and compared to a compilation of Holocene records from the northern North Atlantic. From this regional perspective are shown fundamental timing differences between the gyre dynamics, nuancing classical views of a simple meridional overturning cell.

Sea-surface hydrographical data (annual and seasonnal SST) obtained thanks to the modern analog technique (MAT) after the analysis of planktonic foraminifera assemblages (Relative abundances as published in Mojtahid et al., 2013 for core Ks10B, and from unpublished counts for core PP10-07).

Supplement to: Mary, Yannick; Eynaud, Frédérique; Colin, Christophe; Rossignol, Linda; Brocheray, Sandra; Mojtahid, Meryem; Garcia, Jennifer; Peral, Marion; Howa, Hélène; Zaragosi, Sebastien; Cremer, Michel (2016): Changes in Holocene meridional circulation and poleward Atlantic flow: the Bay of Biscay as a nodal point. Climate of the Past Discussions, 1-30