Elemental Homeostasis at the Individual, Guild and Ecosystem Levels

SternerDEB 9815597生物体内部营养成分往往比周围环境更稳定。 这种现象，稳态，是生态化学计量学的核心因素。 在水生生态系统中，浮游动物在其营养成分方面的变异性远远小于它们所消耗的浮游植物。 在本项目中，将结合实验室和实地调查，在人口、社区和生态系统层面上审查营养物质的动态平衡。 实验室实验将侧重于五种浮游动物，因为它们的营养成分范围很广。 将给动物喂食不同营养比例的食物，并评价动物反应的时间尺度。 在实地项目中，食物资源、浮游动物和鱼类的营养化学将在明尼苏达州代表南北渐变的60个湖泊中进行比较。 据推测，化学变化将减少移动湖泊的食物链从藻类到鱼类。 该项目将测试不同生境中营养水平之间的正负相关性。

SternerDEB 9815597Organisms tend to be more invariant in the internal nutrient content that their surrounding environments. This phenomenon, homeostasis, is a central factor in ecological stoichiometry. In aquatic ecosystems, zooplankton exhibit substantially less variability in their nutrient content than the phytoplankton that they consume. In this project, nutrient homeostasis will be examined at the population, community and ecosystem level using a combination of laboratory and field investigations. Laboratory experiments will focus on five species of zooplankton chosen for their wide range of nutrient contents. Animals will be fed food with different nutrient ratios and the time scales of animal response will be evaluated. In field projects, the nutrient chemistry of food resources, zooplankton and fishes will be compared across a set of 60 lakes in Minnesota representing a north-south cline. It is hypothesized that chemical variability will decrease moving up the lakes' food chains from algae to fish. The project will test for a combination of positive and negative correlations across trophic levels in the different habitats.