Quantifying plankton dynamics in the internal tide using swarms of buoyancy-controlled robots

沿海沃茨是地球上使用最频繁和受到威胁最严重的系统之一。只有深入了解这些地区的物种动态，才能成功地预测和管理沿海资源。沿海无脊椎动物和脊椎动物种群的波动往往是由洋流向成体栖息地提供浮游幼虫所驱动的。许多研究将浮游生物-包括有经济价值物种的幼虫-的跨大陆架迁移与内潮联系起来：内潮是海洋内部以潮汐频率振荡的一种波浪。尽管人们已经研究了几十年浮游生物与内波的相互作用，但还不可能跟踪水下的单个浮游生物。因此，在内波和内潮中浮游生物跨大陆架运输的动力学仍然是自然的。该项目将使用一群新型的、自主的仿南极浮游生物漂流机器人，在现场量化高频内波和内潮驱动的浮游生物跨海岸运输。这项研究将大大提高我们对沿海物种的分布，定居模式和种群连接的理解。 一名博士生将得到支持，与圣地亚哥海洋发现计划合作的教育推广将支持课程创建，课后计划和教师发展。这些研究人员最近已经有能力在海洋中部署成群的模仿南极洲的自主漂流机器人。这些机器人，自主水下探索者（AUE），是1.5升的圆柱体，带有温度和压力传感器，水听器和调节浮力的活塞。地下三维定位是通过声学长基线导航系统完成的。每12秒获得一次每个AUE的三维位置，水平精度约为1米，垂直精度约为1厘米，范围约为5公里。这种高的空间和时间分辨率代表了对传统中性浮力浮子的重大进步。将对20个AUE群进行深度保持或等温线跟踪行为编程，并部署在大陆架上的内部潮汐中，以量化其在潮汐周期中的运输、积累和垂直运动。鱼群将通过一个系泊阵列移动，该阵列由一个垂直剖面走线器、一个热敏电阻链和两个底部安装的声学多普勒海流剖面仪组成。 这些部署的数据将与使用数值模型的过程研究相结合，以测试关于浮游生物行为对内波和内潮中的运输和积累的影响的长期假设。这项研究将提高AUE的业务能力，推进最先进的研究跨货架运输由于内波，并导致新的见解控制幼虫运输的物理和生物相互作用跨越货架。

Coastal waters are among the most heavily used and threatened systems on the planet. Successful prediction and management of coastal resources can only come from a deep understanding of the dynamics of the species in these regions. Fluctuations of coastal invertebrate and vertebrate populations are often driven by the supply of planktonic larvae to the adult habitat by ocean currents. Numerous studies have associated the cross-shelf transport of plankton - including the larvae of economically valuable species - with the internal tide: a wave in the ocean's interior that oscillates at the tidal frequency. Though the interactions of plankton with internal waves have been studied for decades, it has not been possible to track individual plankton underwater. Thus, the dynamics underlying the cross-shelf transport of plankton in internal waves and internal tides remain conjectural. This project will use undersea swarms of novel, autonomous plankton-mimicking drifting robots to quantify, in situ, the cross-shore transport of plankton driven by high-frequency internal waves and the internal tide. This research will significantly enhance our understanding of the distributions, settling patterns, and population connectivity of coastal species. One PhD student will be supported and educational outreach in collaboration with the Ocean Discovery Program in San Diego will support curricula creation, after-school programs, and teacher development.These researchers have recently gained the capability to deploy swarms of plankton-mimicking, autonomous, drifting robots in the ocean. These robots, Autonomous Underwater Explorers (AUEs), are 1.5-liter cylinders with temperature and pressure sensors, a hydrophone, and a piston that regulates buoyancy. Subsurface three-dimensional localization is accomplished through an acoustic long-baseline navigation system. The three-dimensional position of each AUE is obtained every 12 seconds with ~1 m horizontal and 1 cm vertical accuracy with a range of ~5 km. This high spatial and temporal resolution represents a major advance over traditional neutrally buoyant floats. Swarms of 20 AUEs will be programmed with either depth-keeping or isotherm-following behaviors, and deployed in the internal tide on the shelf to quantify their transport, accumulation, and vertical movement over a tidal cycle. The swarms will move through a mooring array consisting of a vertically profiling Wirewalker, a thermistor chain, and two bottom-mounted Acoustic Doppler Current Profilers. Data from these deployments will be combined with process studies using a numerical model to test long-standing hypotheses concerning the effects of plankton behavior on transport and accumulation in internal waves and the internal tide. This research will increase the operational capacity of AUEs, advancing the state of the art in studying cross-shelf transport due to internal waves, and lead to new insights into the physical and biological interactions controlling larval transport across the shelf.