Here, we present two high temporal resolution Holocene sea surface temperature (SST) and salinity (SSS) reconstructions for the SW Atlantic. Mg/Ca data together with the oxygen isotopic composition (δ 18 O) of a shallow dwelling planktonic foraminifera species ( Globigerinoides ruber (pink)). Two marine sediment cores collected at ~ 25°S are used to assess mid- to late Holocene sea surface hydrographic conditions in the continental shelf of the South Brazilian Bight. Our results show multi-centennial-scale changes of up to 2.7 °C in SST and 0.8‰ in ice volume corrected seawater δ 18 O (a proxy for SSS, indicating changes of up to 2 salinity units). In phase, multicentennial-scale negative SST and SSS incursions were interpreted to indicate shelf-break upwelling events and the northward intrusion of the Plata Plume Water (PPW) under a strengthened Brazil Current (BC) flow. The latitudinal SST gradient between our two records (ΔSST 7616–7610 ), applied here as a proxy for the BC strength, supports the existing hypothesis of antiphase between the BC and the North Brazil Current strength during the last 7 ka. Positive ΔSST 7616–7610 values suggest the presence of the PPW at latitudes of up to 25.5°S, while negative ΔSST 7616–7610 values (centred at around 5.4, 4.3, 2.2 and 1.3 cal ka BP) occurring synchronously with cold events in the Northern Hemisphere suggests that the Atlantic Meridional Overturning Circulation played a central role in the SW Atlantic mid- to late Holocene surface hydrographic conditions.

中文翻译：

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南巴西湾中晚期全新世水文波动

在这里，我们提出了西南大西洋的两个高时间分辨率全新世海面温度 (SST) 和盐度 (SSS) 重建。Mg/Ca 数据以及浅层浮游有孔虫物种（Globigerinoides ruber（粉红色））的氧同位素组成（δ 18 O）。在 ~ 25°S 收集的两个海洋沉积物岩心用于评估南巴西湾大陆架的中晚期全新世海面水文条件。我们的结果显示 SST 的百年尺度变化高达 2.7 °C，冰量校正后的海水 δ 18 O（SSS 的代表，表明变化高达 2 个盐度单位）为 0.8‰。相中，百年尺度的负 SST 和 SSS 入侵被解释为表明在加强的巴西洋流 (BC) 流下，架子破裂上涌事件和普拉塔羽流水 (PPW) 向北侵入。我们两个记录之间的纬度 SST 梯度（ΔSST 7616-7610 ），在这里用作 BC 强度的代理，支持了过去 7 ka 期间 BC 和巴西北部海流强度之间反相的现有假设。正的 ΔSST 7616-7610 值表明在高达 25.5°S 的纬度存在 PPW，而负的 ΔSST 7616-7610 值（集中在 5.4、4.3、2.2 和 1 附近）。