Effects of Atmospheric Nitrogen Deposition on Phosphorus Limitation of Freshwater Zooplankton

大气氮沉降对淡水浮游动物磷限制的影响

• 批准号: 0516494
• 负责人: James Elser
• 金额: --
• 依托单位: Arizona State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-09-01 至 2010-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0516494&HistoricalAwards=false
• 关键词: Effects; Atmospheric; Nitrogen; Deposition; Phosphorus

The important plant nutrient, nitrogen (N), can be transported in the atmosphere and deposited into terrestrial and aquatic habitats in rainfall. During recent decades, N deposition has greatly increased as a result of human activities, largely due to expansion of fertilizer application and of formation of nitrates (NO3) during fossil fuel burning. This study will try to determine if N deposition affects lake food webs by changing the chemical composition of the microscopic plants (phytoplankton) that form the base of lake food webs. Specifically, these investigators hypothesize that increasing inputs of N to lakes cause the phytoplankton to become strongly limited by another key element, phosphorus (P). When P-limited, phytoplankton produce biomass that has a very low P content and thus potentially become nutritionally unsuitable for growth of the next feeding level, the zooplankton. (Zooplankton, in turn, provide an important food base for fish, including those that are involved in recreational and commercial fisheries.) To test this, these researchers will measure P limitation of zooplankton growth in lakes receiving different levels of N deposition in central Colorado and in southern Norway. These investigators will also perform a larger scale field study that deliberately manipulates N inputs to experimental mesocosms deployed in a lake that receives low N deposition under normal conditions. This study will help in basic understanding of how lake food webs work while also providing potentially important information about an indirect but potentially important impact of human activity on seemingly pristine ecosystems and the food webs they support.

重要的植物营养素氮（N）可以在大气中运输，并沉积在降雨中的地面和水生栖息地中。 在最近几十年中，由于人类活动的结果，N的沉积大大增加，这主要是由于化石燃料燃烧期间的肥料施用和硝酸盐的形成（NO3）。 这项研究将尝试通过改变形成湖泊食品网基础的微观植物（植物浮游生物）的化学成分（植物植物）的化学成分来确定n个沉积是否会影响湖泊食物网。 具体而言，这些研究者假设增加n到湖泊的投入导致浮游植物受到另一个关键因素磷（P）的强烈限制。 当P限制时，浮游植物会产生非常低的P含量的生物量，因此在营养上可能不适合下一个进食水平的浮游生物。 （反过来，浮游动物为鱼类提供了重要的食物基础，包括涉及休闲和商业渔业的鱼类。）为了测试这一点，这些研究人员将衡量在科罗拉多州中部和挪威南部接受不同水平的N水平的湖泊中浮游生物生长的局限性。 这些研究者还将进行大规模的现场研究，该研究故意操纵在正常情况下在正常条件下接收低N沉积的湖中部署的实验中心的N输入。 这项研究将有助于基本了解湖泊食品网的工作方式，同时还提供有关人类活动对看似原始的生态系统及其支持的食物网的潜在重要信息。