Elemental ecology: Ecological stoichiometry, limiting nutrients, and lake foodwebs

水产消费者和他们的食物之间的营养失衡会严重影响湖泊食物网和生态系统过程中的生态相互作用。例如，藻类中的低磷含量会降低湖泊浮游动物的生长和繁殖率。由于加拿大许多湖泊的特点是营养投入低(如果不是极低的话)，营养限制可能特别普遍，而且对我们湖泊生态系统的结构和功能的影响被低估。尽管营养失衡可能很重要，但关于营养失衡仍然存在不确定性--关于哪些元素最具限制性，这种限制如何影响无脊椎动物及其食物，以及这如何影响湖泊中的碳储存。该计划将采用实验室和田间相结合的方法研究营养物质对水生生态系统的影响。特别是，我们将描述湖泊食物网中营养成分的模式，记录动物和食物对养分可获得性变化的反应，并测量暴露在不同营养浓度下的有机物的分解速度。通过这样做，我们将解决新的生态学问题，即为什么会出现营养失衡，以及它们对水生群落的影响。此外，这项工作将有助于开发新的方法来跟踪水生生物的营养压力，并将它们的营养需求与生态动态联系起来。总之，这项工作将加深我们对营养物质如何影响湖泊食物网的理解，这对于更好地缓解和管理人类营养物质污染的影响是必要的。

Nutrient imbalances between aquatic consumers and their food can strongly affect ecological interactions in lake food webs and ecosystem processes. For example, low phosphorus content in algae reduces growth and reproductive rates of lake zooplankton. As many Canadian lakes are characterized by low (if not extremely low) nutrient inputs, nutritional constraints may be especially common and underappreciated in their effects on the structure and function of our lake ecosystems. Despite their possible importance, there remains uncertainty regarding nutrient imbalances- about which elements are most limiting, how this limitation affects invertebrates and their food, and how this affects carbon storage in lakes. This program will study the effects of nutrients in aquatic ecosystems using a combination of laboratory and field based approaches. In particular, we will characterize patterns of nutrient content in lake food webs, document animal and food responses to changes in nutrient availability, and measure rates of decomposition in organic matter exposed to different nutrient concentrations. By doing so, we will address novel ecological questions about why nutrient imbalances develop and what their consequences are for aquatic communities. In addition, this work will help develop new methods of tracking nutritional stress in aquatic organisms and connecting their nutritional requirements to ecological dynamics. Altogether, this work will deepen our understanding of how nutrients affect lake food webs, which is necessary to better mitigate and manage effects of human nutrient pollution.