DISSERTATION RESEARCH:Ecological Stoichiometry and Predation: Examining Life History Trade-Offs in Daphnia

水蚤是湖泊生态系统的组成部分。 水蚤生物学的许多方面已经得到很好的表征，包括食物质量限制对生长和繁殖的作用，捕食者-猎物相互作用的动力学，以及完整的基因组序列，使其成为综合研究化学，环境和生态学分子组成的理想模式生物。 该项目调查食物质量和捕食对水蚤生活史的影响，包括生长速度和生殖输出，通过量化基因型和一系列环境条件（反应规范）之间的相互作用产生的一组可见的性状。 将在实地检验基于实验室结果的预测，从而提供一个将营养与自然环境中的捕食联系起来的机会。 该研究解决了食物质量，捕食，物种相互作用和群落稳定性的湖泊生态系统中的基因型变异的重要性。 所获得的结果将提高人们对环境中元素比例的重要性以及对生物组成和生态系统功能的影响的认识。该项目的更广泛目标是更全面地了解水生生态系统的复杂性。 通过结合化学，生理和分子的方法来了解生态系统动态，人类引起的环境变化的影响，特别是湖泊富营养化通过磷富集，可以预测在分子，个人和食物网水平。 鉴于全球湖泊环境面临的压力日益增加，加深对淡水生态系统人为改变后果的了解至关重要。

Daphnia, the water flea, is an integral component of the lake ecosystem. Many aspects of Daphnia biology have been well characterized, including the role of food quality constraints on growth and reproduction, the dynamics of predator-prey interactions, and the complete genome sequence, making it an ideal model organism for an integrated examination of the chemical, environmental, and molecular components of ecology. This project investigates the effect of food quality and predation on Daphnia life history, including growth rate and reproductive output, by quantifying a set of visible traits produced by the interaction between the genotype and a range of environmental conditions (reaction norms). Predictions based on laboratory results will be tested in the field, providing an opportunity to relate nutrition to predation in a natural environment. The research addresses the importance of food quality, predation, and genotypic variation on species interactions and community stability in the lake ecosystem. The results obtained will increase awareness of the importance of elemental ratios in the environment and the impact on organismal composition and ecosystem function.The broader objective of the project is a more complete understanding of the complexity of the aquatic ecosystem. By incorporating chemical, physiological, and molecular approaches to understand ecosystem dynamics, the impact of human-induced environmental change, particularly the eutrophication of lakes via phosphorus enrichment, can be predicted at the molecular, individual, and food web levels. Given the growing stress on the lake environment worldwide, an increased understanding of the consequences of anthropogenic modification of freshwater ecosystems is vitally important.