Element Linkage and Growth-Competition Tradeoffs in Freshwater Zooplankton

该项目将探索一个新的通用模型，该模型将三个参数——生物体的生长速度、其元素组成和一个被称为催化能力的新参数——联系在一起，以预测当一种元素的浓度控制另一种元素的变化时，生长速度和竞争能力之间将存在权衡。这个模型被称为“元素联系模型”，它是高度通用的，并且只做了一个假设——生物体保持平衡生长，或者生物体生物量中所有元素的特定变化率相等。先前大量关于淡水浮游动物中磷浓度的工作支持元素连锁模型对这些生物的应用。本项目将关注模型预测的增长与竞争的权衡。食物阈值实验（测量生长率）和竞争试验将启动，使用17种枝海洋浮游动物和一种浮游动物的6个克隆来比较元素连锁模型在几个分类水平上的预测。这些比较将用于检测种间生长竞争的权衡，连锁模型预测这种权衡将发生在低磷食物上，而不是高磷食物上。这些实验使用另一个众所周知的实验系统彻底探索了这种权衡，并将化学计量学（营养丰度和比例）模型的应用扩展到竞争性相互作用。这项研究的更广泛的影响将是推动一个潜在的重要的生态学新模型。将为PI、研究生、技术人员以及通过明尼苏达大学正在进行的倡议参与该项目的本科生和高中教师提供职业和教育机会。

This project will explore a new and general model that ties together three parameters - an organism's growth rate, its elemental composition, and a new parameter referred to as catalysis power - to predict that there will be a tradeoff between growth rate and competitive ability when the concentration of one element controls changes in another. The model, called the Elemental Linkage Model, is highly general and makes a single assumption - that organisms maintain balanced growth or equal specific rates of change of all elements within organism biomass. Considerable previous work on phosphorus concentrations in freshwater zooplankton supports the application of the Element Linkage model to these organisms. This project will focus on the growth-competition tradeoff the model predicts. Food threshold experiments (to measure growth rates) and competition trials will be initiated using seventeen species of cladoceran zooplankton and six clones of one species to compare predictions of the Elemental Linkage Model at several taxonomic levels. These comparisons will be used to detect interspecific growth-competition tradeoffs, which the linkage model predicts will occur on low-P but not high-P foods. These experiments explore thoroughly this tradeoff using an otherwise well-known experimental system and extend the application of stoichiometric (nutrient abundances and ratios) models to competitive interactions. Broader impacts of the research will be to advance a potentially important new model in ecology. Career and educational opportunities will be generated for the PI, a graduate student, a technician and extended to undergraduates and high school teachers, who will participate in the project via ongoing University of Minnesota initiatives.