Collaborative Research: Larval Transport in a Coupled-Estuary-Shelf System: A Modeling Study

本课题将以青蟹为模式生物，采用理论方法研究河口-陆架耦合系统中平流、混合、生物行为和环境变异性对幼虫运输的交互影响。尽管以前对幼虫运输的研究侧重于出口和重新进入河口，但迫切需要系统地审查多种因素对河口之间幼虫区域规模交换和招募可变性的相对重要性。数值环流模型和粒子跟踪算法已经成熟到可以解决这些问题的地步。研究人员将使用流体动力学-粒子跟踪耦合模型来系统地分离和评估平流、混合、生物行为和环境变异性的影响，并整合它们复杂和非线性的相互作用。观测到的风和流驱动的环流模式将用中大西洋海湾的可计算可处理的半理想化水动力模式来模拟。数值模型中的粒子将利用该地区现场调查和实验室行为研究提供的大量信息来模拟蓝蟹的早期生命阶段。这是第一次在三维数值模式中系统地关注平流、混合、生物行为和环境变异性之间的复杂相互作用的模拟工作，该模式包括对亚格子尺度湍流过程的最新理解，垂直分辨的蓝蟹幼虫行为，以及检查河口系统之间交换的能力。对于具有重要娱乐和商业价值的蓝蟹，了解其数量变化的原因和沿海种群之间联系的强度是一个重要的研究途径。蓝蟹渔业是一种宝贵的资源，其可持续性目前在切萨皮克湾受到质疑。了解产生补充变异性的物理过程以及河口种群的相互关联程度，将有助于管理人员为维持可持续的蓝蟹渔业做出更明智的决定。虽然研究的重点是蓝蟹，但研究结果将涉及控制浮游幼体在大陆架上大规模运输的因素、它们返回育苗区以及河口系统之间交换的可能性等基本的、普遍的问题。除了加强我们对影响幼虫运输和招募的复杂因素的了解外，这项研究计划还包括强大的教育和推广部分，包括开发互动网页。一名本科暑期学生将接受数值建模和数据分析培训。此外，一名教员将获得与科学家合作并将研究成果转化为教学计划的经验。参与MA-COSEE计划的研究人员、一名教师研究员的指导以及网页的开发将促进科学家和教育工作者之间的直接互动，并使研究成果得以广泛传播。

This project will investigate the interactive effects of advection, mixing, organism behavior and environmental variability on larval transport in a coupled-estuary-shelf system using a theoretical approach, and the blue crab, Callinectes sapidus, as the model organism. Although previous research on larval transport has focused on export and re-entry to an estuary, there is a critical need to systematically examine the relative importance of multiple factors on the regional-scale exchange of larvae between estuaries and on recruitment variability. Numerical circulation models and particle-tracking algorithms have matured to the point where they are ready to address these problems. Investigators will use a coupled hydrodynamic-particle tracking model to systematically isolate and evaluate the effects of advection, mixing, organism behavior and environmental variability, and to integrate their complex and nonlinear interactions. Observed wind- and flow-driven circulation patterns will be simulated with a computationally tractable semi-idealized hydrodynamic model of the Middle Atlantic Bight. Particles within the numerical model will simulate blue crab early-life stages using the extensive information available from field investigations and laboratory behavior studies in this region. This is the first modeling effort that systematically focuses on the complex interactions between advection, mixing, organism behavior and environmental variability in a 3D numerical model that includes the latest understanding of sub-grid scale turbulent processes, vertically resolved blue crab larval behavior, and the ability to examine exchange between estuarine systems. Understanding the cause of recruitment variability and the strength of connections between coastal populations is a critical avenue of research for the recreationally and commercially important blue crab. The blue crab fishery is a valuable resource whose sustainability is currently in question in Chesapeake Bay. Understanding the physical processes that generate recruitment variability, and the degree of interconnectedness of estuarine populations, will help managers make more informed decisions for maintaining a sustainable blue crab fishery. Although focused on blue crabs, research results will be address fundamental, universal questions about factors that control large-scale transport of planktonic larvae on continental shelves, their return to nursery areas, and potential for exchange between estuarine systems. In addition to enhancing our understanding of the complex factors that affect larval transport and recruitment, this research program has a strong education and outreach component, including development of an interactive web page. One undergraduate summer student will gain numerical modeling and data analysis training. Also, one teacher Fellow will gain experience working with scientists and translating research results into lesson plans. The investigators involvement in the MA-COSEE program, the mentoring of a teacher Fellow, and development of a web page will promote direct interaction between scientists and educators and enable broad dissemination of research results.