Understanding copepod life-history and diversity using a next-generation zooplankton model

进化塑造了一个物种的生理，生活史和行为，以适应其范围内的物理条件和捕食者和猎物的社区。在一个群落中，物种的数量取决于温度等物理特性和初级生产力的大小和时间等生物特性，以及捕食等生态相互作用。尽管生物多样性与温度等特性之间存在着众所周知的相关性，但驱动这些相关性的机制却没有得到很好的描述，特别是在海洋中。调查人员将对海洋生态系统的多样性模式进行基于模型的调查，重点是哲水蚤桡足类。大西洋两岸的多样性变化提出了三个主要假设，桡足类的多样性与环境稳定性，生产力和基于大小的捕食。为了测试这些，研究人员将开发一种新的桡足类种群动态模型。该模型将发展阶段和质量作为连续体，导致一个单一的偏微分方程丰度作为阶段和质量的函数。这种方法有利于使用计算流体力学的算法来解决许多桡足类丰度模型的数值色散问题。这个新的建模框架将通过建立一个模型的物种哲水蚤finmarchicus和Pseudocalanus newmani进行测试，比较先前的观察和模型的两个对比的生态系统，缅因州和圣劳伦斯湾的模型的结果。该模型形式化的温度依赖的发展，质量依赖和温度依赖的增长，质量依赖的死亡率之间的权衡。将进行一系列一维模拟，包括一系列环境条件。每个模拟将初始化与许多不同的“物种”，其中一个物种是由一组参数指定的关键生理和生活史参数。这些将与营养-浮游植物-微型浮游动物模型相结合，并进行多年的整合。这一程序将产生一个社区的桡足类适应条件，在每个模拟环境。通过研究模拟的桡足类群落如何对物理条件、生产力和捕食的变化作出反应，将测试桡足类多样性模式的机制。该项目将改进重要桡足类物种的模型，这些模型可以纳入正在进行的和未来的生态系统预测。本研究所建立的桡足类地理界限资料，可支持气候变迁下桡足类分布的估计。该模型的设计将适用于流域规模的模型。通过允许适应物理和生物条件，新兴桡足类群落应该提供更现实的估计气候变化的影响。该项目将支持一名研究生和一名博士后助理的专业发展。它还将每年聘请一名本科生暑期实习生。与此项目相关的概念将在SeascapeModeling.org的博客上向更广泛的公众传达。

Evolution has shaped the physiology, life history, and behavior of a species to the physical conditions and to the communities of predators and prey within its range. Within a community, the number of species is determined by both physical properties such as temperature and biological properties like the magnitude and timing of primary productivity, and ecological interactions such as predation. Despite well-known correlations between diversity and properties such as temperature, the mechanisms that drive these correlations are not well-described, especially in the oceans. The investigators will conduct a model-based investigation of diversity patterns in marine ecosystems, focusing on calanoid copepods. Diversity changes on both sides of the Atlantic suggest three main hypotheses, relating copepod diversity to environmental stability, productivity, and size-based predation. To test these, the investigators will develop a novel model of copepod population dynamics. The model treats developmental stage and mass as continua, leading to a single partial differential equation for abundance as a function of stage and mass. This approach facilitates the use of algorithms from computational fluid mechanics to resolve numerical dispersion problems that characterize many copepod abundance models. This new modeling framework will be tested by building a model for the species Calanus finmarchicus and Pseudocalanus newmani to compare the results of the model with prior observations and models for two contrasting ecosystems, the Gulf of Maine and Gulf of St. Lawrence. The model formalizes trade-offs between temperature-dependent development, mass-dependent and temperature-dependent growth, and mass-dependent mortality. A series of 1-D simulations will be conducted, encompassing a range of environmental conditions. Each simulation will be initialized with many distinct "species," where a species is described by a set of parameters specifying key physiological and life history parameters. These will be coupled to a nutrient-phytoplankton-microzooplankton model and integrated for many years. This procedure will produce a community of copepods adapted to conditions in each simulated environment. By studying how the modeled copepod communities respond to changes in physical conditions, productivity, and predation, mechanisms accounting for copepod diversity patterns will be tested.The project will lead to improved models for important copepod species that can be incorporated into ongoing and future ecosystem forecasts. The information on copepod biogeographic limits developed by this study could support estimates of copepod distributions under climate change. The model will be designed to work in a basin-scale model. By allowing adaption to physical and biological conditions, the emergent copepod communities should provide more realistic estimates of the impact of climate change. The project will support the professional development of one graduate student and one postdoctoral associate. It will also engage one undergraduate summer intern each year. Concepts related to this project will be communicated to the wider public on a blog at SeascapeModeling.org.