SGER: An opportunity to study the impact of nutrient pulsing in an oligotrophic forest stream in South Dakota

由于人类不断增加的营养物沉积往往超过了许多陆地生态系统吸收它们的能力，溪流作为陆地流域营养物运输工具的重要性日益增加。本研究将评估营养脉冲对南达科他州低营养（少营养）森林溪流的影响。急流溪是一条泉水喂养的小溪，其特点是营养物质浓度很低。它一直在经历令人讨厌的藻类繁殖。这种现象是不寻常的，因为典型的藻类繁殖与人为的营养负荷直接相关，然而这种藻类的繁殖？硅藻（双硅藻）？通常与营养贫乏的水域有关。由于这种硅藻会严重影响溪流生态系统的结构和功能，并影响渔业，南达科他州狩猎，鱼类和公园部门正在向拉皮特溪添加缓释肥料，试图防止D. geminata的开花。为了评估这种营养负荷对该河流的生物和非生物成分的影响，本研究将检查给药地点的上游和下游的营养动态。由于硅藻的生长对重要营养元素的最佳配比较为敏感，本研究将重点研究碳、氮、磷、硅等营养元素；以及生物反应，如酶活性、溶解氧和叶绿素产量的变化。这些措施将有助于了解生态系统的健康状况。该项目还加强了学生的研究培训和教育，同时产生了广泛适用于其他生态系统的宝贵数据。

The significance of streams as transporters of nutrients from terrestrial watersheds is growing as the increasing deposition of nutrients by humans often exceeds the capacity of many terrestrial ecosystems to absorb them. This study will evaluate the impact of nutrient pulsing in a low-nutrient (oligotrophic) forest stream in South Dakota. Rapid Creek is a spring fed creek characterized by very low nutrient concentrations. It has been experiencing a nuisance algal bloom. This phenomenon is unusual because typically algal blooms are directly related to anthropogenic nutrient loading, yet blooms of this algae?a diatom (Didymosphenia geminate)?are often associated with nutrient-poor waters. Since this diatom can significantly impact stream ecosystem structure and function and impact fisheries, the South Dakota Game, Fish, and Parks Department is adding slow-release fertilizer to Rapid Creek in an attempt to prevent the bloom of D. geminata. To evaluate the impact of this nutrient loading on the biological and abiotic components of this stream, this study will examine nutrient dynamics upstream and downstream of the dosing site. Since the growth of diatoms is sensitive to the optimal ratio of important nutrient elements, this study will focus on nutrients such as carbon, nitrogen, phosphorus and silica; and on biological responses such as changes in enzyme activity, dissolved oxygen and chlorophyll production. These measures will provide insights into the health of the ecosystem. This project also enhances student research training and education while generating valuable data that will be broadly applicable to other ecosystems.