The pool of particulate organic matter driven by primary production in western boundary continental margins is known to be smaller than the highly eutrophic upwelling systems of eastern margins. Its production and export, however, can be high compared to productive ocean environments due to inherent specific physical dynamics such as mesoscale instabilities driven by the boundary current. To investigate how such physical process influence nutrients, chlorophyll-a and particulate matter on the outer shelf of the South Brazil Bight, two oceanographic cruises were conducted three months apart (November 2012 and January 2013), both under wind conditions that favor intrusions of South Atlantic Central Water (SACW). Our results showed two distinct hydrographic scenarios derived by the relative positions of oceanographic fronts in the outer shelf and shelf break region, associated with the Brazil Current (BC). In November 2012, the oligotrophic Tropical Water occupied a larger area of the continental shelf. Low nutrients and chlorophyll-a concentrations were found, typical of a regenerated production system. In contrast, maximum concentration of particulate matter and particulate inorganic carbon occurred at deeper layers in this period, together with low POC:PON ratio — probably from sediment resuspension. In January 2013, a strong shelf break upwelling was detected that enhanced SACW intrusion, notably increasing nutrient availability in the euphotic zone and the chlorophyll-a concentration at deeper layers. These deep chlorophyll maximum layers contribute to the production and accumulation of particulate organic carbon and nitrogen under these conditions. BC mesoscale instabilities appear to act as a particulate matter transport and export agent to the deep waters throughout the South Brazil Bight outer shelf.

众所周知，西部边界大陆边缘的初级生产驱动的颗粒有机物的储量要小于东部边缘高度富营养化的上升流系统。但是，由于固有的特定物理动力学（如边界流驱动的中尺度不稳定性），与生产性海洋环境相比，其产量和出口量可能很高。为了研究这种物理过程如何影响巴西南部海岸线外层的养分，叶绿素-a和颗粒物，我们在三个有利于南方入侵的风力条件下分别进行了三个月的海洋巡游（2012年11月和2013年1月）。大西洋中央水域（SACW）。我们的研究结果显示了两种不同的水文情景，它们是由与巴西洋流（BC）相关的外陆架和陆架断裂带海洋前沿的相对位置得出的。2012年11月，贫营养的热带水占据了大陆架的更大面积。发现低养分和叶绿素-a浓度，这是再生生产系统的典型特征。相反，在此期间，颗粒物和颗粒无机碳的最大浓度出现在较深层，同时POC：PON比率也很低-可能是由于沉积物的再悬浮。2013年1月，检测到强烈的架子破裂上升流，增强了SACW入侵，显着增加了富营养区的养分利用率和更深层的叶绿素a浓度。在这些条件下，这些深层叶绿素最大层有助于颗粒有机碳和氮的产生和积累。卑诗省中尺度的不稳定性似乎是颗粒物质向整个南巴西湾外层架的深水输送和出口的媒介。