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群落。在一个群落内，物种的数量既由温度等物理属性和初级生产力的大小和时间等生物属性决定，也由捕食等生态相互作用决定。尽管众所周知，生物多样性与温度等特性之间存在关联，但驱动这种关联的机制并没有得到很好的描述，特别是在海洋中。研究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，重点是甲鱼类桡足类动物。大西洋两岸的多样性变化提出了三个主要假说，将桡足类多样性与环境稳定性、生产力和基于大小的捕食联系起来。为了验证这一点，研究人员将开发一种新的桡足类种群动态模型。该模型将发育阶段和质量看作是连续的，导致了丰度作为阶段和质量的函数的单一偏微分方程式。这种方法便于使用计算流体力学的算法来解决许多桡足类丰度模型所特有的数值弥散问题。这一新的建模框架将通过建立物种Calanus finmarchicus和Pseudocalanus newmani的模型来测试，以将该模型的结果与缅因湾和圣劳伦斯湾这两个不同生态系统的先前观测和模型进行比较。该模型规范了依赖温度的发育、依赖于质量和依赖温度的增长和依赖于质量的死亡率之间的权衡。将进行一系列一维模拟，包括一系列的环境条件。每个模拟都将使用许多不同的“物种”进行初始化，其中一个物种由一组参数描述，这些参数指定关键的生理和生命历史参数。这些将与营养物-浮游植物-微型浮游动物模型相结合，并整合多年。这一过程将产生一个适应每个模拟环境条件的桡足类群落。通过研究所建模型的桡足类群落如何对物理条件、生产力和捕食性的变化作出反应，将测试桡足类多样性模式的机制。该项目将导致对重要的桡足类物种的改进模型，这些模型可以纳入正在进行的和未来的生态系统预测。这项研究开发的关于桡足类生物地理界限的信息可以支持对气候变化下的桡足类分布的估计。该模型将被设计成在盆地规模的模型中工作。通过允许适应物理和生物条件，新兴的桡足类群落应该对气候变化的影响提供更现实的估计。该项目将支持一名研究生和一名博士后助理的专业发展。它还将每年聘用一名本科生暑期实习生。与该项目相关的概念将在SeascapeModeling.org的博客上与更广泛的公众交流。

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.