Abstract The western tropical Atlantic is strongly influenced by the Amazon, receiving the full discharge from the largest river basin of the world. In order to ascertain the coastal-oceanic gradient in abundance and composition of planktonic decapod communities along the Amazon River Plume (ARP) and its retroflection, 33 plankton samples were obtained along three sampling transects: Coastal and oceanic area influenced by the ARP (Coastal IARP and Ocean IARP, respectively), and oceanic waters without ARP influence (Ocean). A total of 13,117 specimens, belonging to 33 taxa, were analyzed. The distribution of planktonic decapod communities was strongly influenced by the Amazon discharge, showing the following patterns: (1) The coastal-oceanic gradients in decapod abundance are similar to other shelf areas of eastern South America, with higher abundance in the area under ARP influence, (2) meroplanktonic decapods dominate in coastal and some oceanic areas due to the offshore transport of coastal organisms along the ARP retroflection, and (3) the ARP is clearly responsible for the observed differences in community structure between the three transects. Furthermore, this study highlights the importance of coastal and shelf environments as main sources of planktonic decapods for pelagic ecosystems in the tropical Atlantic during the period of strong North Brazil Current retroflection.

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亚马逊河羽流对热带大西洋浮游十足目动物的影响

摘要 西热带大西洋受亚马逊河的强烈影响，接收了世界上最大的河流流域的全部流量。为了确定沿亚马逊河羽流 (ARP) 及其反射的浮游十足类群落丰度和组成的沿海 - 海洋梯度，沿三个采样横断面获取了 33 个浮游生物样本：受 ARP (Coastal IARP) 影响的沿海和海洋区域和海洋 IARP），以及没有 ARP 影响的海洋水域（海洋）。共分析了属于 33 个分类群的 13,117 个标本。浮游十足类群落的分布受亚马逊流域的强烈影响，呈现出以下模式：(1) 十足类动物丰度的沿海-海洋梯度与南美洲东部其他陆架区相似，随着 ARP 影响区域的丰度更高，(2) 由于沿海生物沿 ARP 反射的近海运输，小型浮游十足类在沿海和一些海洋区域占主导地位，(3) ARP 显然是观察到的群落差异的原因三个横断面之间的结构。此外，这项研究强调了沿海和陆架环境作为热带大西洋中上层生态系统中浮游十足目浮游动物主要来源的重要性，在巴西北部海流强烈逆反射期间。(3) ARP 显然对观察到的三个样带之间的群落结构差异负有责任。此外，这项研究强调了沿海和陆架环境作为热带大西洋中上层生态系统中浮游十足目浮游动物主要来源的重要性，在巴西北部海流强烈逆反射期间。(3) ARP 显然对观察到的三个样带之间的群落结构差异负有责任。此外，这项研究强调了沿海和陆架环境作为热带大西洋中上层生态系统中浮游十足目浮游动物主要来源的重要性，在巴西北部海流强烈逆反射期间。