Collaborative Research: Improving quantification of larval dispersal in the global coastal ocean to understand the genetic structure, biogeography, and spread of benthic organisms

许多海洋物种的后代或幼体被洋流携带或分散。这种扩散影响着物种在哪里存在，它们在空间中的遗传变异，以及它们如何随着气候变化传播到新的地方。这个项目使用一个现代的全球洋流模型来量化这种扩散，并探索洋流是如何影响它的。该方法的新颖之处在于模拟电流的高空间分辨率及其变异性。将对扩散的详细估计与观察到的漂流者走过的路径以及物种分布及其遗传变异的信息进行比较。大多数先前的研究都忽略了洋流来估计扩散，而是使用后代在水中漂浮的时间。当考虑到洋流时，幼虫从近海向海岸的运输是主要的焦点，而不是沿海岸发生的运输。该项目解决了这两个缺陷，并能够在全球范围内检查扩散对沿海物种空间分布的影响。该项目包括开发软件工具和数据集，以及培训视频，使研究人员、生态系统管理者、环境机构和其他感兴趣的各方能够自己模拟不同日期和地点的扩散。两名博士和六名本科生通过开展相关的跨学科研究，从海洋生态学到数值模拟和物理海洋学，为科学事业进行培训。该项目使用现代高分辨率全球模型来解释沿海海洋物种的幼虫扩散如何定量影响全球沿海海洋的生物地理学、系统地理学和入侵性。该项目的创新之处在于，根据现有的大规模数据集，对沿岸扩散的海洋学现实估计，包括洋流的大小和空间变异性进行了测试。产品包括使研究界能够轻松地估计沿全球海洋海岸散布的幼虫的工具，取代迄今为止占主导地位的粗糙且经常不正确的估计。利用墨卡托1/12度数据同化的全球环流模式计算的洋流计算的扩散路径，与全球漂流项目的地表漂流数据进行了验证。这些新的扩散数据被用来确定沿岸变化对幼虫扩散的作用：1)连通性遗传估计的大小，2)生物地理边界的位置，以及3)世界各地开放海岸线对浮游生物幼虫入侵物种的易感性变化。这项研究通过量化幼虫在近海幼虫池中被洋流沿海岸运输的距离来改进先前的研究，从而可以在全球范围内检查扩散如何影响物种内部和物种之间的空间结构。全球的、基于地点的海洋学对扩散影响的量化加深了对洋流在物种分布中所起作用的理解。反过来，了解扩散重要性的区域差异有助于预测物种对变化条件的区域特定反应。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

The offspring or larvae of many marine species are carried or dispersed by ocean currents. This dispersal impacts where species persist, their genetic variability in space, and how they can spread to new locations as climate changes. This project uses a modern model of global ocean currents to quantify this dispersal and to explore how currents affect it. The novelty of this approach comes from the high spatial resolution of the simulated currents and their variability. The detailed estimates of dispersal are compared to observed pathways traveled by drifters and against information of species distributions and of their genetic variability. Most prior efforts ignored ocean currents to estimate dispersal, using instead the time that offspring are floating in the water. When the ocean currents were in fact considered, the delivery of larvae to the coast from offshore was the main focus, rather than transport occurring along the shore. This project addresses both deficiencies and enables examination of the effect of dispersal on the distribution of coastal species space at a global scale. The project includes the development of software tools and data sets, along with training videos, that allow researchers, ecosystem managers, environmental agencies, and other interested parties to model dispersal for different dates and locations on their own. Two PhD and six undergraduate students are being trained for scientific careers by having them develop related inter-disciplinary investigations, spanning from marine ecology to numerical modeling and physical oceanography. This project uses a modern high-resolution global model to explain how larval dispersal of coastal marine species quantitatively affects the biogeography, phylogeography, and invasibility of coastal oceans globally. The project is innovative in that oceanographically realistic estimates of alongshore dispersal, including the magnitude and spatial variability of ocean currents, are tested against existing large-scale datasets. Products include tools that allow the research community to easily estimate the dispersal of larvae along the coast of the global ocean, replacing the crude, and often incorrect, estimates that have dominated approaches to date. Dispersal paths calculated with currents from the Mercator 1/12 degree data-assimilative global circulation model are validated against surface drifter data from the Global Drifter Project. This new dispersal data is used to determine the role of alongshore variation in larval dispersal on 1) the magnitude of genetic estimates of connectivity, 2) the location of biogeographic boundaries, and 3) the variation in susceptibility of open coastlines around the world to invasive species with planktonic larvae. This study improves on previous studies by quantifying the distance larvae are transported alongshore by ocean currents in the offshore larval pool, allowing an examination of how dispersal affects spatial structuring within and among species at a global scale. Global, place-based quantification of the influence of oceanography on dispersal deepens the understanding of the role currents play in species distributions. In turn, understanding the regional differences in the importance of dispersal helps predict regionally specific responses of species to changing conditions.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.