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

水生消费者和他们的食物之间的营养不平衡可以强烈影响湖泊食物网和生态系统过程中的生态相互作用。例如，藻类中的低磷含量降低了湖泊浮游动物的生长和繁殖率。由于许多加拿大湖泊的特点是营养投入低（如果不是极低），营养限制可能特别常见，并且对我们湖泊生态系统的结构和功能的影响未被充分认识。尽管它们可能很重要，但营养失衡仍存在不确定性-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。该计划将使用实验室和现场为基础的方法相结合的水生生态系统中的营养物质的影响进行研究。特别是，我们将描述湖泊食物网中营养成分的模式，记录动物和食物对营养物质可用性变化的反应，并测量暴露于不同营养物质浓度的有机物的分解率。通过这样做，我们将解决新的生态问题，为什么营养不平衡的发展和它们的后果是什么水生群落。此外，这项工作将有助于开发跟踪水生生物营养压力的新方法，并将其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，这对于更好地减轻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.