Collaborative Research: Linking behavior and transport of larvae using waves and turbulence as cues

许多生活在海底的海洋物种都有幼虫，它们在水柱中的行为影响着它们的扩散和成虫的分布。蜗牛幼虫在波浪和湍流的提示下会更努力地向上游动或下沉，目前尚不清楚幼虫是否能利用这些物理提示在栖息地内停留或在栖息地之间导航。在波浪下游动的幼虫可能会在表层海水中由波浪引起的岸边漂移而滞留在大陆架上。然而，海洋变暖导致幼虫在春天释放得更早，因为那时海浪更大，沿海上升流较弱，有可能将幼虫带到较浅的水域，这超过了成虫的温度承受能力。研究人员将使用大西洋中部湾和邻近河口的物理模型来测试海浪和湍流如何影响运输模式、成虫栖息地附近的滞留以及气候引起的成虫分布变化的假设。该项目将模拟海洋环流和幼虫跟踪代码，其中包括波浪作为行为线索和运输机制；这些产品将向公众开放。研究生将做一篇相关的论文。本科生将通过一个由美国国家科学基金会资助的REU项目、阿雷斯蒂项目（Aresty program）、罗格斯大学科学与工程研究项目（Rutgers research in Science and Engineering program）和斯基德莫尔暑期研究项目（Skidmore Summer research program）参与其中。阿雷斯蒂项目让罗格斯大学的不同本科生参与研究，以提高他们在STEM专业的留用率。模型产出将用于为本科生开发学习材料，打包为案例研究，通过国家科学案例研究教学中心分发。研究结果也将通过Skidmore Encore系列讲座呈现给成人（55岁及以上）学习者。波浪的独特之处在于，它为浮游生物幼虫提供了一种与水平运输机制直接相关的行为线索，而新发现的幼虫对波浪的反应可能会对幼虫的运输和物种分布产生反直觉的影响。两种同类蜗牛的邻近栖息地的波浪气候不同：Tritia obsoleta居住在波浪较小的湍流入口和河口，而Tritia trivittata居住在波浪较大的大陆架。这两种幼虫分别感知波浪和湍流，分别为加速和涡旋诱导的身体旋转。后期河口幼虫主要表现出湍流诱导的下沉，这可以减少从入海口和河口的运输，而陆架幼虫也表现出波浪诱导的向上游动，这可以通过斯托克斯漂移帮助滞留在陆架上。自20世纪60年代以来，陆架物种的活动范围已经转移到更温暖的水域，这与基于耐热性的预测相反。这种转变可能是由波浪诱导的幼虫运输驱动的；由于海洋变暖导致产卵提前，幼虫将在春季遇到更大的波浪和较弱的上升流，加剧斯托克斯漂移和向内陆大陆架温暖、较浅水域的陆上运输。该项目将使用数值模型来验证水流诱导的幼虫行为与运输途径、局部滞留和气候驱动的范围变化之间的联系。波将分别作为行为线索和通过加速和斯托克斯漂移的平流的来源。结果将有助于解决斯托克斯漂移、欧拉回流和上升流如何相互作用以运输幼虫的不确定性。数值实验将描述气候驱动的产卵物候变化是如何影响幼虫运输的，从而有可能确定大陆架物种向温暖水域转移的复杂范围背后的机制。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。

Many bottom-dwelling marine species have larvae whose behavior in the water column impacts dispersal and adult distributions. Snail larvae swim up with more effort or sink in response to cues from waves and turbulence, and it remains unclear whether larvae can use these physical cues for retention within or navigation among habitats. Larvae that swim up under waves may be retained over the continental shelf by wave-induced shoreward drift in surface waters. However, ocean warming causes larvae to be released earlier in spring when waves are larger and coastal upwelling is weaker, potentially carrying larvae into shallower waters that exceed the adults' temperature tolerance. The investigators will use a physical model of the Middle Atlantic Bight and adjacent estuaries to test hypotheses about how waves and turbulence affect transport patterns, retention near adult habitats, and climate-induced shifts in adult distributions. The project will produce simulations of ocean circulation and larval tracking codes that include waves both as behavior cues and as a transport mechanism; these products will be made publicly available. A graduate student will do a related dissertation. Undergraduate students will be involved through an NSF-funded REU program, the Aresty Program, which engages Rutgers' diverse undergraduates in research to boost retention in STEM majors, the Rutgers Research in Science and Engineering program, which targets underrepresented minorities, and the Skidmore Summer Research program. Model outputs will be used to develop learning materials for undergraduates, packaged as a case study for distribution through the National Center for Case Study Teaching in Science. Research results will also be presented to adult (55 and over) learners through the Skidmore Encore lecture series.Waves are unique in providing planktonic larvae with a behavior cue directly tied to a horizontal transport mechanism, and newly discovered larval responses to waves could have counter-intuitive impacts on larval transport and species distributions. Wave climates differ in the adjacent habitats of two congeneric snails: Tritia obsoleta occupies turbulent inlets and estuaries where waves are small, while Tritia trivittata occupies the continental shelf where waves are much larger. These two species' larvae sense waves and turbulence separately as acceleration and vorticity-induced body rotation, respectively. Late-stage estuarine larvae mainly exhibit turbulence-induced sinking that could reduce transport out of inlets and estuaries, whereas shelf larvae also exhibit wave-induced upward swimming that could aid retention over the shelf via Stokes drift. Since the 1960s, the shelf species' range has shifted into warmer water, opposite to predictions based on thermal tolerance. This shift may be driven by wave-induced larval transport; as ocean warming induces earlier spawning, larvae will encounter larger waves and weaker upwelling in spring, intensifying Stokes drift and onshore transport toward warmer, shallower waters of the inner shelf. The project will use numerical models to test hypotheses linking flow-induced larval behaviors to transport pathways, local retention, and climate-driven range shifts. Waves will be included as a source of both behavior cues and advection through acceleration and Stokes drift, respectively. Results will help resolve uncertainties about how Stokes drift, Eulerian return flow, and upwelling interact to transport larvae. Numerical experiments will describe how climate-driven changes in spawning phenology affect larval transport, potentially identifying the mechanism behind perplexing range shifts of shelf species into warmer water.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.