Dissertation Research: Influences of Inorganic Sediment on Productivity in Lotic Ecosystems

9321549格列佛洛特海生态系统由一系列已知的生物群落组成，这些生物群落受到采矿、林业和农业泥沙负荷的严重影响。迄今为止，为了考察不同的泥沙负荷对生态系统功能的影响而对整个生态系统进行操纵的受控试验很少。%使用八条建造的渠道，合作调查将研究不同的泥沙负荷对鱼类种群、初级生产者、底栖无脊椎动物和微生物的影响。该项目的这一部分将评估沉积物对光照制度、自由流湍流和营养物质通量的影响模型，以及初级生产者对这些因素的响应模型。一个主要目标是通过使用模拟河道水动力特性的改进型围堰来提高生产率测量的准确性。此外，将分别使用以下技术测量每个渠道的光合作用、河流生产力和底栖生物呼吸：氧气和14C测量；明/暗瓶子和底栖生物调查；海底呼吸仪和微电极。%泥沙对上述环境因素的影响评估和更准确的生产力测量应阐明保护河流群落免受有害土地管理做法影响的LATIC标准。

9321549 Gulliver Lotic ecosystems are composed of an array of biological communities known o be heavily impacted by sediment loads originating from mining, forestry, and agriculture. To date, few controlled experiments have been conducted in which whole ecosystems are manipulated for the purpose of examining variable sediment load effects on ecosystem functioning. %%% Using eight constructed channels, a collaborative investigation will study different sediment load impacts on fish populations, primary producers,, benthic invertebrates, and microorganisms. This part of the project will evaluate models of sediment effects on light regimes, free stream turbulence and nutrient fluxes, as well as models of primary producer response to these factors. A primary objective is to improve the accuracy of productivity measurements by using modified enclosures that simulate channel hydrodynamic characteristics. In addition, photosynthesis, stream productivity and benthic respiration will be measured in each channel using the following techniques, respectively: oxygen and 14C measurements; light/dark bottles and diel surveys; benthic respirometer and microelectrodes. %%% Evaluation of sediment impacts on the above environmental factors and more accurate measurements of productivity should elucidate the lotic criteria which can protect stream communities from deleterious land management practices.