High sea surface chlorophyll concentration on the Argentine Continental Shelf frequently extends to the deep ocean in the vicinity of the Brazil/Malvinas Confluence (BMC). The offshore transport of shelf waters likely plays a key role in the biogeochemical balance of the western South Atlantic and promotes the offshore transport of planktonic species. We analyze data from an oceanographic survey carried out in the western South Atlantic shelf between 31°S and 38°S in October 2013. We describe the distribution and circulation of the water masses and focus on the exchanges with the open ocean. On‐shelf subsurface intrusions of oceanic waters and river discharge supply nutrients to the shelf. A low‐salinity tongue of Río de la Plata (RDP) waters extends northward to 32°S. Below these waters Subantarctic and Subtropical Shelf Waters (SASW and STSW) meet to form the Subtropical Shelf Front. The main SASW branch, oversaturated in oxygen and with high‐fluorescence mixes with a detachment of Brazil Current waters at 38°S and is exported offshore along the BMC. A second branch of SASW reaches 33°S mixing along its way with RDP and STSW and returns southward after splitting into an onshore and an offshore branch. The offshore branch is exported to the open ocean through the BMC. These export routes are in overall qualitative agreement with those indicated by a high‐resolution reanalysis. We estimate a net off‐shelf transport (geostrophic [96.2%] plus Ekman [3.8%]) of 3.44 Sv to the open ocean between 32.1°S and 37.7°S. The majority of the offshore flow occurs between 34.7°S and 37.7°S.

中文翻译：

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南大西洋西部大陆架的环流和水文学，并出口至深海：30°S至40°S

阿根廷大陆架上的高海表叶绿素浓度经常延伸至巴西/马尔维纳斯汇合处（BMC）附近的深海。架子水的海上运输可能在南大西洋西部的生物地球化学平衡中发挥关键作用，并促进浮游物种的海上运输。我们分析了2013年10月在南大西洋西部31°至38°S西部大陆架进行的海洋学调查得出的数据。我们描述了水团的分布和环流，并着眼于与远洋的交换。海水和河流排放物在架子上的地下侵入为该架子提供了营养。普拉达河（RDP）水域的低盐度舌头向北延伸至32°S。在这些水之下，亚南极和亚热带大陆架水域（SASW和STSW）汇合形成亚热带大陆架前缘。SASW的主要分支富含氧气，并带有高荧光混合物，与38°S的巴西水域分开，并沿BMC出口到近海。SASW的第二个分支沿途与RDP和STSW混合达到33°S，然后分裂为陆上和海上分支后向南返回。离岸分支机构通过BMC出口到公海。这些出口路线与高分辨率再分析表明的出口路线总体上具有定性。我们估计，在32.1°S和37.7°S之间，到开放海洋的净现成陆运量（地营养[96.2％]加埃克曼[3.8％]）为3.44 Sv。大部分海上流动发生在34.7°S至37.7°S之间。