Larval dispersal capacity and realized connectivity: integration of physical transport models, larval plasticity, and gene flow in the north central Pacific

许多重要的海洋物种成年后生活在海底或附着在海底，它们在随洋流漂移的微小幼虫阶段在不同地点之间迁徙，并在新的区域定居。大多数幼虫太小，无法在海洋中找到或跟踪，因此我们对幼虫在自然条件下能存活多长时间和生长速度知之甚少。这限制了我们了解海洋物种如何在偏远栖息地定居的能力，也限制了我们在多大程度上进行远程基因交流，以帮助种群适应不断变化的海洋条件。由于幼虫很难被跟踪，它们的活动通常是通过洋流的运输模型和对种群之间共同遗传变异的分析来间接估计的。然而，这些方法很少结合在一起，运输模型中的幼虫部分往往基于对幼虫能够存活多长时间的不切实际的估计。该项目同时从种群基因组模型和幼虫运动的运输模型中产生对幼虫扩散的估计。幼虫移动模型的基础是来自幼虫饲养实验的数据，这些实验模拟了幼虫在北中太平洋经历的自然食物和温度条件。这种结合的方法有助于解释海洋物种如何在非常孤立的岛屿地区定居和生存，以及它们跨越遥远海洋距离交换基因的可能性有多大。该项目正在为三名研究生和几名本科生研究助理提供跨学科培训。此外，调查人员正在与一名科学外展协调员合作，让夏威夷高中生参与实地和实验室工作。这项活动正在使教育目标和评估与夏威夷教育部开发的基于文化和地点的科学教育框架NāHopena A‘o(H)保持一致。该项目的中心目标是了解夏威夷群岛与热带中北部太平洋其他偏远岛链之间的远程连接的比率和模式。具体地说，研究人员正在整合幼虫生活史、生物物理运输模型和关于基因流的种群遗传推断的经验数据，以了解许多物种的幼虫延长发育和延缓变态的能力如何影响海洋系统中的扩散和连通性模式。他们正在测量与环境有关的条件下浮游幼虫的持续时间，以测试幼虫在通往和离开夏威夷群岛的扩散路径上扩展发育的能力。这些实验室实验的结果，以及过去20年收集的水柱数据，将被用于幼虫运输模型，该模型包括对温度、食物可获得性和不同生活史特征的估计。该领域从同一物种收集的种群基因组数据将评估基因流在塑造夏威夷和该地区其他孤立的群岛和岛屿之间的基因组结构中的作用，确定往返夏威夷的幼虫传播路径，测试对比基因流动的历史模型，并估计幼虫进出夏威夷的传播率。该项目由生物海洋学计划和既定的刺激竞争研究计划(EPSCoR)共同资助。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Many important marine species live on or attached to the bottom of the ocean as adults, and they move between places and colonize new areas during microscopic larval stages that drift with ocean currents. Most larvae are too small to find or track in the ocean, so we know little about how long larvae can survive and how fast they grow under natural conditions. This limits our ability to understand how marine species colonize remote habitats, or how much potential there is for long-distance gene exchange that can help populations adapt to changing conditions in the sea. Because larvae are so hard to follow, their movement is often estimated indirectly from transport models of ocean currents and analyses of shared genetic variation among populations. These approaches are rarely combined, however, and the larval component of transport models is often based on unrealistic estimates of how long larvae can stay viable. This project is simultaneously generating estimates of larval dispersal from population genomic modeling and transport models of larval movement. The larval movement models are grounded in data from larval rearing experiments that mimic the natural food and temperature conditions that larvae experience in the North Central Pacific. The combined approach is helping explain how marine species colonize and persist in very isolated island areas and how likely they are to exchange genes across vast oceanic distances. The project is providing interdisciplinary training for three graduate students and several undergraduate research assistants. In addition, the investigators are partnering with a science outreach coordinator to engage Hawaiian high school students in field and lab work. This activity is aligning educational goals and assessments with a culture-and place-based framework for science education, Nā Hopena A‘o (HĀ), developed by the Hawaii Department of Education.The central goal of this project is to understand rates and patterns of long-distance connectivity between the Hawaiian archipelago and other remote island chains of the tropical north central Pacific. Specifically, the investigators are integrating empirically-derived data on larval life histories, biophysical transport models, and population genetic inferences about gene flow to understand how patterns of dispersal and connectivity in marine systems are affected by the capacity of larvae of many species to prolong development and delay metamorphosis. They are measuring planktonic larval duration under environmentally relevant conditions to test the capacity of larvae to extend development in the dispersal pathways leading to and from the Hawaiian Islands. Results from these laboratory experiments, as well as water-column data gathered over the past two decades, will be used in larval transport models that incorporate estimates of temperature, food availability, and varying life-history traits. Population genomic data gathered from the same species in the field will assess the role of gene flow in shaping genomic structure between Hawai'i and other isolated archipelagos and islands in the region, identify larval dispersal pathways to and from Hawai'i, test contrasting historical models of gene flow, and estimate rates of larval dispersal in and out of Hawai'i. This project is jointly funded by the Biological Oceanography Program and the Established Program to Stimulate Competitive Research (EPSCoR).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.