Table_1_Mesoscale Eddies Structure Mesopelagic Communities.XLSX

Mesoscale eddies play a key role in structuring open ocean ecosystems, affecting the entire trophic web from primary producers to large pelagic predators including sharks and elephant seals. Recent advances in the tracking of pelagic predators have revealed that these animals forage in the mesopelagic and the depth and duration of their foraging dives are affected by the presence of eddies. The ways in which eddies impact the distribution of mesopelagic micronekton, however, remain largely unknown. During a multi-seasonal experiment we used a shipboard scientific echosounder transmitting at 38 kHz to observe the distribution of acoustic backscattering in the energetic mesoscale eddy field of the northwestern Atlantic. Observations were collected at 24 stations with 6 located in anticyclonic and 7 in cyclonic eddies. The sampled anticyclonic eddies are characterized by intense acoustic backscattering in the mesopelagic and changes in the intensity of acoustic backscattering layers match gradients of surface properties. Furthermore, mesopelagic daytime backscattering is positively correlated with sea level anomaly. These results suggest that anticyclonic eddies in the northwestern Atlantic impact the distribution of mesopelagic micronekton and may have the potential to locally enhance or structure spatially mesopelagic communities.

中尺度涡旋在构建开阔大洋生态系统方面发挥着关键作用，它们影响着从初级生产者到大型浮游捕食者，包括鲨鱼和海象在内的整个食物链。近期在追踪浮游捕食者方面的进展揭示了这些动物在次表层进行觅食，而其觅食潜水的深度和持续时间受涡旋存在的影响。然而，涡旋如何影响次表层微细浮游生物的分布，目前仍知之甚少。在多季节实验中，我们利用一艘船上的38 kHz科学回声测深仪，观察了西北大西洋富有活力的中尺度涡旋场中的声学回波散射分布。在24个站点收集了观测数据，其中6个位于反气旋涡旋，7个位于气旋涡旋。采集到的反气旋涡旋以次表层强烈的声学回波散射为特征，声学回波散射层强度的变化与表面特性的梯度相匹配。此外，次表层白天回波散射与海平面异常呈正相关。这些结果表明，西北大西洋的反气旋涡旋对次表层微细浮游生物的分布产生影响，并可能具有在局部增强或构建空间性次表层群落结构的潜力。