Dissertation Research: Planktonic Coupling in Lakes of Differing Trophic Status: A Multi-Level Experimental Approach

目前湖沼学的研究主要集中在 营养供应和食物网结构对全球变暖的贡献 调节生态系统的生产力。 这一努力 促进社区和生态系统观点的综合。 这项提案的主要目标是调查一个重要的 从最近的这种综合中出现的问题是： 浮游植物-浮游动物耦合强度在 不同营养状态的湖泊 我们建议回答这个问题 通过对浮游动物进行实验操作来解决问题 四湖围隔生态系统中的营养物质， 营养状态的范围。 浮游动物的因子操纵 和营养物质将直接评估放牧的影响和程度 通过浮游动物营养物促进藻类生长 再生 浮游植物暴露于广泛的 浮游动物密度将揭示非线性藻类反应， 评估它们对浮游动物密度的反应， 由季节性或年际变化引起。 最后通过 评估藻类对物种、群落和 总（“生态系统”）水平，我们将尝试整合 具有人口、社区和生态系统特征的方法 生态 这项研究的结果将有助于理论和 和应用湖沼学家来了解这个复杂的 浮游植物和浮游动物之间的相互作用。 这 相互作用代表着一个关键的环节， 光合生产的消费者更高的食物网， 将食物网结构的变化转化为 生态系统特性，如初级生产力。

Considerable current effort in limnology focuses on the contributions of nutrient supply and food web structure to the regulation of productivity in planktonic ecosystems. This effort promotes a synthesis of community and ecosystem perspectives. The main goal of this proposal is to investigate an important question that has emerged from such recent syntheses: how does the strength of phytoplankton-zooplankton coupling change between lakes of differing trophic status? We propose to answer this question by performing experimental manipulations of zooplankton and nutrients in mesocosms in four lakes which encompass a broad range of trophic states. Factorial manipulations of zooplankton and nutrients will directly assess grazing impacts and the extent of enhancement of algal growth by zooplankton nutrient regeneration. Exposure of phytoplankton to a broad range of zooplankton densities will reveal non-linear algal responses and evaluate their responses to zooplankton densities that might arise from seasonal or inter-annual variation. Finally, by evaluating algal responses at the species, community, and aggregate ("ecosystem") levels, we will try to integrate approaches characteristic of population, community, and ecosystem ecology. The results of this study will assist both theoretical and applied limnologists in understanding the complex interaction between phytoplankton and zooplankton. This interaction represents the crucial link which transfers photosynthetic production to consumers higher in the food web and which translates changes in food web structure into changes in ecosystem properties such as primary productivity.