CAREER: Beyond N and P: How trace metal limitation influences stream ecosystem function

覆盖在河流生态系统床上的藻类为无脊椎动物和鱼类提供了重要的食物资源，并能拦截污染物。在光照和营养均衡的条件下，藻类生长迅速，资源缺乏导致藻类生长缓慢，对污染物的过滤效率低下。藻类需要几十种营养物质，但只有两种主要营养物质（氮和磷）在溪流中得到了广泛的研究。最近在海洋和大型湖泊的研究表明，微量金属对藻类的生长很重要。该项目将对微量金属在水藻生长中的作用提供基本的认识，并探索微量金属缺乏对污染过滤的影响。这项工作也将为高中生和大学生提供经验，以促进现代生物学所需的关键技能。现代生物学融合了许多其他科学领域的知识，这项工作对微量金属的研究提供了一种跨学科的方法，可以成为发展中科学家的典范。本项目将通过从斑块到河流尺度的实验，研究微量金属缺乏对河流生态系统结构和功能的影响程度、原因和后果。该项目将回答三个基本问题：(1)微量金属对五大湖溪流中藻类生长的影响频率有多高？(2)改变营养平衡如何改变藻类群落？(3)改变痕量金属的可用性如何改变藻类对污染的过滤？这项研究将在98条五大湖溪流中使用营养物扩散基质（NDS）来确定微量金属影响藻类的位置和条件。随后的研究将测量不同痕量金属条件下的藻类群落和污染物吸收率。斑块尺度上的结果将在全河尺度上通过人工河道和分河试验得到验证。该项目将在教室和实验室中使用NDS实验，为高中生和本科生提供真实的研究体验。研究人员将与肯特州立大学向上发展数学科学项目合作，向高中生介绍跨学科科学，并为他们提供真实的、基于当地的研究经验。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Algae covering the bed of stream ecosystems provide key food resources for invertebrates and fishes and can intercept pollutants. Algae grow rapidly when provided with light and a balanced supply of nutrients, and a lack of resources causes slow growth and inefficient filtering of pollutants. Algae require dozens of nutrients, but only two major nutrients (nitrogen and phosphorus) have been extensively studied in streams. Recent work in the ocean and large lakes has shown that trace metals are important for the growth of algae. This project will provide fundamental understanding of the role of trace metals in the growth of stream algae and explore the consequences of trace metal deficiencies on pollution filtering. This work will also provide experiences for high school and undergraduate students that promote key skills required of modern biology. Modern biology incorporates knowledge from many other scientific fields and this work’s study of trace metals provides an interdisciplinary approach that can be a model for developing scientists.This project will use experiments from the patch to stream scale to study the extent, cause, and consequences of trace metal deficiency for stream ecosystem structure and function. The project will answer three fundamental questions: (1) How often do trace metals influence algae growth in Great Lakes streams?, (2) How does changing the nutrient balance alter algal communities?, and (3) How does changing trace metal availability alter pollution filtering by algae? The study will use nutrient diffusing substrates (NDS) in 98 Great Lakes streams to identify locations and conditions where trace metals are influencing algae. Ensuing studies will measure algal communities and pollutant uptake rates under different trace metal conditions. Results at the patch scale will be confirmed at the whole stream scale with experiments in artificial channels and divided streams. The project will use NDS experiments in classrooms and laboratories to give high school and undergraduate students authentic research experiences. The researchers will work with the Kent State Upward Bound Math Science program to introduce high school students to interdisciplinary science and provide them with authentic, place-based research experiences in their local streams.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.