Marine zooplankton play a pivotal position in the pelagic ecosystem and, as one of their principal members, copepods represent by far the most significant direct link between phytoplankton and the higher trophic levels. In this study, observational evidence of the effect of a mesoscale cyclonic eddy on the abundance of copepods (adult calanoids, adult cyclopoids and all copepodite stages) in the Bay of La Paz, southern Gulf of California, a region recognized as exhibiting high biodiversity, is presented. During a multidisciplinary research cruise in February 2006, high-resolution hydrographic profiles were obtained from a grid of stations throughout the bay, and oblique zooplankton hauls were made in its north-central portion. The results showed the presence of a mature mesoscale cyclonic eddy, which extended to 110 m depth and 30 km diameter, reaching a surface azimuthal velocity of 20 cm s^–1 at its periphery. Below the mixed layer at 50 m depth this eddy induced a cold-core water dome (~16.25 °C) at its center. Within this cold water dome, nutrients concentrations were much higher than outside the eddy. Nitrate reached up to 15 μM, soluble reactive phosphorous (SRP) up to 1.6 μM, and soluble reactive silicate (SRSi) up to 30 μM within the eddy. The total abundance of the organisms analyzed varied according to group: the calanoid copepods reached values of 8112 ind 100 m^–3, the cyclopoid copepods of 4281 ind 100 m^–3, and the highest abundance was recorded by all copepodite stages, of 32,076 ind 100 m^–3. The influence of the cyclonic structure on copepod abundance was to induce the formation of a circular shape around the eddy periphery, which could be called a ‘copepod belt shape’. We suggest that several mechanisms induce this aggregation, including: 1) the affinity of these organisms for waters with a favorable temperature, and 2) the availability of food (phytoplankton) generated by the presence of the cyclonic eddy and the sub-mesoscale processes there, as well as by the presence of a bathymetric sill. These results represent the first observational report on the influence of a mesoscale cyclonic eddy in the Bay of La Paz on zooplankton organisms in winter, which should contribute to a better understanding of the dynamics of this highly productive area.

海洋浮游动物在远洋生态系统中起着举足轻重的作用，作为其主要成员之一，co足类动物是浮游植物与较高营养级之间最直接的直接联系。在这项研究中，观测证据表明中尺度的旋风涡流对加利福尼亚南部海湾拉巴斯湾（被认为生物多样性高的地区）的co足类动物（成年的类人猿，成年的独眼巨人和所有足足类动物）的丰度产生了影响，被表达。在2006年2月的一次多学科研究航行中，从整个海湾的站点网格中获得了高分辨率的水文剖面图，并且在其中北部部分进行了倾斜的浮游动物牵引。结果表明存在成熟的中尺度气旋涡，涡旋延伸到深度为110 m，直径为30 km，^–1在其外围。在混合层下方50 m深度处，该涡流在其中心诱发了一个冷芯水穹顶（〜16.25°C）。在这个冷水穹顶中，营养物质的浓度比涡流外部的要高得多。涡流中的硝酸盐含量高达15μM，可溶性反应性磷（SRP）高达1.6μM，可溶性可溶性硅酸盐（SRSi）高达30μM。所分析生物的总丰度因组而异：an足类pe足类动物的值达到8112 ind 100 m ^–3，摆线足类pe足类动物的数量为4281 ind 100 m ^–3，并且在所有的pe足类阶段记录的丰度最高，为32,076 ind 100 m ^–3。气旋结构对co足类的丰度的影响是在涡流周围引起圆形的形成，这可以称为“足形带状”。我们建议几种机制引起这种聚集，包括：1）这些生物体对温度适宜的水的亲和力； 2）旋风涡旋的存在和那里的亚中尺度过程所产生的食物（浮游植物）的可用性，以及存在测深窗台。这些结果代表了有关冬季拉巴斯湾中尺度旋风涡对浮游生物的影响的第一份观测报告，这应有助于更好地了解这一高产区的动态。