Foraging of Planktivorous Seabirds and Hydrographic Processes in the Aleutians

将进行一项多学科研究，以检验这样一种假设，即食浮性海鸟将在潮汐和亚潮间流与水深测量相互作用的地方集中觅食，在空间上可预测的上升流和锋面上运输和聚集浮游动物。据推测，准永久锋面是由混合中的水平梯度与潮汐速度和底部深度的梯度相关而产生的，对鸟类来说将是重要的。将比较布尔迪尔岛附近浅水区(100米)和深水区(600米)的物理过程和浮游生物分布，以及鸟类在水平和垂直维度对猎物集中的反应。将采用先进的技术，包括声学多普勒海流剖面仪(ADCP)、综合测深仪、多开合网(MOCNESS)和计算机化的数据输入和结果实时分析，以优化船舶的使用。这项研究提供了一个独特的机会，可以结合新技术的好处，研究物理过程如何影响支持更高营养水平的浮游生物的分布和集中。这项研究将是为数不多的同时研究阿留申群岛西部海鸟的物理过程、浮游动物分布和丰度以及海鸟觅食生态的研究之一。这套信息将使人们能够将海洋岛屿上的海鸟的海洋生态与之前研究过的附近大陆岛屿上的海鸟的海洋生态进行比较。

A multidisciplinary study will be conducted to test the hypothesis that planktivorous seabirds will concentrate their foraging where tidal and sub-tidal currents, interacting with bathymetry, transport and concentrate zooplankton near the surface in spatially predictable upwellings and fronts. It is hypothesized that quasi-permanent fronts, caused by horizontal gradients in mixing associated with gradients in tidal velocity and bottom depth, will be of importance to the birds. Physical processes and plankton distributions in both shallow (100 m) and deep (600 m) passes near Buldir Island will be compared, as will avian responses to concentrations of prey in both the horizontal and vertical dimensions. Advanced technologies including an Acoustic Doppler Current Profiler (ADCP), an integrating echosounder, multiple opening-closing nets (MOCNESS) and computerized data entry and real-time analyses of results to optimize use of the ship will be employed. The study provides a unique opportunity to combine the benefits of new technologies for investigating how physical processes affect the distribution and concentration of plankton that support higher trophic levels. The study will be one of the few to examine simultaneously physical processes, zooplankton distributions and abundance, and the foraging ecology of marine birds in the western Aleutians. This suite of information will permit comparison of the marine ecology of seabirds on oceanic islands with that of seabirds on nearby continental islands studied previously.