Dissertation research -- The role of mineralization in nutrient spiralling in heterotrophic streams

论文研究——矿化在异养溪流营养螺旋中的作用

• 批准号: 1011307
• 负责人: Jackson Webster
• 金额: $ 0.9万
• 依托单位: Virginia Polytechnic Institute and State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-09-01 至 2013-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1011307&HistoricalAwards=false
• 关键词: Dissertation; research; role; mineralization; nutrient

Human activity has greatly increased the amount of nutrients, such as nitrogen and phosphorus, applied to the global landscape. Much of this nutrient load is transported to coastal areas by streams and rivers. However, streams are not passive conduits but are sites of significant nutrient transformation. Nutrients may enter streams in dissolved inorganic forms, are transported a certain distance by water flow, and are eventually transformed into organic forms by stream organisms, which need these chemicals for maintenance and growth. This research will focus on the final stage of this cycle where stream organisms, such as bacteria, fungi, and insects, return excess nutrients to the water. Specifically, this research will determine the effect of increased nutrient input on nutrient transformations by stream organisms and their ability to influence the transport of nutrients downstream. The investigators will use a stable isotope of nitrogen to measure several nutrient processing metrics in both field and laboratory settings. This combined approach will allow for the description of broad patterns across time and space as well as the determination of specific mechanisms responsible for the observed patterns. The increased nutrient loading occurring around the globe is causing a suite of environmental problems including declines in biodiversity, contamination of drinking water, and anoxia of coastal waters. The role of streams in transporting these excess nutrients from terrestrial to marine systems makes understanding the fate of nutrients within streams vital to policy makers attempting to mitigate the negative effects of nutrient loading. The temporal and spatial scope of this research will help fill a gap in the understanding of stream nutrient cycling and will add to the body of knowledge available to policy makers. This research also provides opportunities for undergraduate students to participate in the scientific process and contribute to the understanding of a relevant environmental issue.

人类活动极大地增加了氮和磷等营养物质的数量，应用于全球景观。大部分营养物质通过溪流和河流被输送到沿海地区。然而，溪流不是被动的管道，而是重要的营养转化场所。营养物质可能以溶解的无机形式进入溪流，通过水流运输一定距离，最终由溪流生物转化为有机形式，这些生物需要这些化学物质来维持和生长。这项研究将集中在这个循环的最后阶段，在这个阶段，细菌、真菌和昆虫等溪流生物将多余的营养物质返回水中。具体来说，这项研究将确定增加营养物质输入的影响，对营养物质的转化流生物和他们的能力，影响营养物质的运输下游。研究人员将使用氮的稳定同位素来测量田间和实验室环境中的几种营养处理指标。这种综合方法将允许描述跨越时间和空间的广泛模式，并确定对观察到的模式负责的具体机制。地球仪上不断增加的营养负荷正在引起一系列环境问题，包括生物多样性下降、饮用水污染和沿海沃茨缺氧。河流在将这些多余的营养物质从陆地系统输送到海洋系统中的作用使得了解河流中营养物质的命运对于试图减轻营养物质负荷的负面影响的政策制定者至关重要。这项研究的时间和空间范围将有助于填补在河流养分循环的理解的空白，并将增加现有的知识体系的决策者。这项研究还为本科生提供了参与科学过程的机会，并有助于了解相关的环境问题。