REU: Mechanisms Controlling the Production and Fate of Insect Detritivores in the Profundal of Lakes

湖泊中产生的许多有机物质下沉到深海沉积物中，在那里它支持一个底栖有害食肉动物群落，通常由摇蚊科幼虫占据主导地位。这些昆虫是浮游植物和鱼类之间重要的营养纽带。人们普遍认为，浮游植物产量较高的湖泊，这种有害的群落将产生较高的次生生产力，最终由鱼类产生。我们不知道这些生态系统组成部分之间的联系有多紧密，也不了解这种耦合的可能的营养和生活史机制。这项研究的问题是，深摇蚊的产量是否反映了对该群落的食物供应，或者人口密度是否经常太低，无法充分利用现有资源。试点实验将开发操纵食物供应和向深海底栖生物招募幼虫的技术，以测试有关可能限制深海昆虫生产的因素的假设。一个主要深海物种的次生生产模型也将量化由于捕食上升蛹而对鱼类造成的产量损失。这项工作将阐明深海底栖生物在初级生产和鱼类之间的营养联系中的作用。

Much of the organic matter produced in lakes sinks to profundal sediments where it supports a community of benthic detritivores, often dominated by larvae of the Chironomidae. These insects (midges) are an important trophic link between phytoplankton and fish. It is generally thought that lakes more productive of phytoplankton will have higher secondary production by this detritivore community, and ultimately by fish. We do not know how closely these ecosystem components are linked, nor do we understand possible trophic and life history mechanisms for such coupling. This research asks whether production by profundal chironomids reflects the food supply to this community, or whether population densities are often too low to fully utilize available resources. Pilot experiments will develop techniques for manipulating food supply and larval recruitment to the profundal benthos to test hypotheses regarding factors that may limit profundal insect production. A model of secondary production by a dominant profundal species will also quantify the loss of production to fish through predation on ascending pupae. This work will clarify the role of the profundal benthos in the trophic linkage between primary production and fish.