Abstract Plankton composition and density, and domoic acid (DA) content in microplankton and mesozooplankton were assessed over the northern Patagonian coastal shelf in late austral summer 2013. Maximum values of DA in these two plankton fractions as well as maximum densities of both Pseudo-nitzschia spp. (mainly the toxigenic P. australis) and DA potential vectors were only detected on the southern coast of San Matias Gulf and the eastern coast of Valdes Peninsula. In this zone, waters were characterized by low temperature, high nitrate, and intermediate values of silicic acid and phosphate. Based on the high association between the DA values recorded and the values of either micro- and mesozooplankton grazer density or biomass, we inferred that DA transfer from Pseudo-nitzschia spp. occurred largely through the small copepods Euterpina acutifrons and Oithona nana, Calanidae nauplii and Calanidae copepodites, Noctiluca scintillans, and euphausiid developmental stages. Small copepods, Calanidae nauplii and copepodites, and cladocerans were proposed as novel DA vectors although this suggestion requires experimental confirmation. This study provides the first lines of evidence of the co-occurrence of Pseudo-nitzschia spp. blooms with DA production and accumulation in mesozooplanktonic grazers at the base of the food web and of the environmental and oceanographic conditions that seem to favor these processes over the northern Patagonian shelf coasts.

中文翻译：

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DOMOIC 酸、Pseudo-nitzschia spp 和位于西南大西洋北部巴塔哥尼亚海岸的远洋食物网底部的潜在载体

摘要 2013 年夏末在北巴塔哥尼亚海岸陆架上评估了微型浮游生物和中型浮游生物的浮游生物组成和密度以及软骨藻酸 (DA) 含量。这两种浮游生物组分中 DA 的最大值以及两种 Pseudo-nitzschia 的最大密度属 （主要是产毒 P. australis）和 DA 潜在载体仅在圣马蒂亚斯湾南海岸和瓦尔德斯半岛东海岸检测到。在该区域，水域的特点是温度低、硝酸盐含量高、硅酸和磷酸盐含量中等。基于记录的 DA 值与微型和中型浮游动物食草动物密度或生物量值之间的高度关联，我们推断出来自 Pseudo-nitzschia spp 的 DA 转移。主要发生在小型桡足类 Euterpina acutifrons 和 Oithona nana、Calanidae nauplii 和 Calanidae 桡足类、夜光藻和 euphausiid 发育阶段。小型桡足类、Calanidae 无节幼体和桡足类以及枝角类动物被提议作为新的 DA 载体，尽管这一建议需要实验证实。这项研究提供了 Pseudo-nitzschia spp 共存的第一条证据。在食物网底部的中型浮游食草动物中，随着 DA 的产生和积累，以及似乎有利于巴塔哥尼亚北部陆架海岸这些过程的环境和海洋条件的水华。枝角类和枝角类被提议作为新的 DA 载体，尽管这一建议需要实验证实。这项研究提供了 Pseudo-nitzschia spp 共存的第一条证据。在食物网底部的中型浮游食草动物中，随着 DA 的产生和积累，以及似乎有利于巴塔哥尼亚北部陆架海岸这些过程的环境和海洋条件的水华。枝角类和枝角类被提议作为新的 DA 载体，尽管这一建议需要实验证实。这项研究提供了 Pseudo-nitzschia spp 共存的第一条证据。在食物网底部的中型浮游食草动物中，随着 DA 的产生和积累，以及似乎有利于巴塔哥尼亚北部陆架海岸这些过程的环境和海洋条件的水华。