Holocene palaeoceanographic history of the western South Atlantic

Although the circulation of the western South Atlantic tightly controls the meridional heat and salt transport, our knowledge about its long-term past changes is still fragmented and sparse. While many studies focused their attention on the last glacial and deglaciation periods, Holocene studies mostly lack of an integrated analysis from the subtropical and midlatitude regions. The analysis of selected regionally distributed palaeoceanographic records along the western South Atlantic between 27 and 39S reveals that, although weaker in amplitude than the dramatic shifts of the last glacial cycle, the Brazil-Malvinas Confluence region showed substantial changes throughout the Holocene. The shift in the location of both southern and northern source waters in the Atlantic implied a strengthening of the Southern Atlantic Meridional Overturning Circulation since the Mid-Holocene. This, together with the progressive southward displacement of the Brazil-Malvinas Confluence confirms the progressive weakening of the Atlantic Meridional Overturning Circulation towards the preindustrial times.

Automated summary

Although our knowledge about the long-term past changes in the circulation of the western South Atlantic is fragmented and sparse, analysis of selected palaeoceanographic records reveals substantial changes in the Brazil-Malvinas Confluence region during the Holocene. The Southern Atlantic Meridional Overturning Circulation strengthened since the Mid-Holocene, while the Atlantic Meridional Overturning Circulation weakened towards the preindustrial times.