Collaborative Research: Trophic Structure and the Stoichiometry of Nitrogen and Phosphorus in the Pelagic Food Web

合作研究：远洋食物网中的营养结构和氮、磷的化学计量

• 批准号: 9119781
• 负责人: Robert Sterner
• 金额: $ 21.33万
• 依托单位: University of Texas at Arlington
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-02-15 至 1995-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9119781&HistoricalAwards=false
• 关键词: Collaborative; Research; Trophic; Structure; Stoichiometry

Ecologists are increasingly realizing that patterns of storage and processing of energy and chemical elements in ecosystems are strongly influenced by the composition of the ecological communities present in the ecosystem. In lakes, the abundance of "top predators" (i.e. fish-eating fish species like bass) can have strong effects on all levels of the system, including the abundance and productivity of plant producers and the cycling of chemical elements. This occurs because predatory fish consume plankton-feeding fish, like minnows, which in turn influence herbivorous consumers (zooplankton). Finally, zooplankton both regulate the abundance of plant producers (phytoplankton) and decomposers (bacteria) and recycle nutrients. This project focusses on the effects of food web structure on the relative availability of nutrient elements critical for microbial growth (nitrogen and phosphorus). It tests the predictions of a recently-developed, physiologically-based theory designed to understand how different zooplankton species regenerate nitrogen and phosphorus present in their food. By altering the dynamics of these herbivorous zooplankton, fish predation can therefore influence the cycling of nitrogen and phosphorus. Based at the Experimental Lakes Area in Canada, the main research approaches will in involve experimental manipulations of nutrients and zooplankton in large enclosures in lakes as well as whole-lake manipulations of food-web structure (via introduction of pike to two lakes which lack such a fish-eating species). THese studies have direct application to understanding the processes controlling elemental cycling in ecosystems; such processes play a critical role in various areas of direct societal, including global climate change, the dynamics of contaminants in the environment, and degradation of water supplies.

生态学家越来越认识到，生态系统中能量和化学元素的储存和处理模式受到生态系统中生态群落组成的强烈影响。在湖泊中，“顶级捕食者”(即像鲈鱼这样的食鱼物种)的丰度可能对系统的各个层面产生强烈的影响，包括植物生产者的丰度和生产力以及化学元素的循环。这是因为捕食性鱼类消耗以浮游生物为食的鱼类，如小鱼，这反过来又影响食草性消费者(浮游动物)。最后，浮游动物既调节植物生产者(浮游植物)和分解者(细菌)的丰度，又循环营养物质。本项目重点研究食物网状结构对微生物生长至关重要的营养元素(氮和磷)相对可获得性的影响。它测试了最近开发的一种基于生理学的理论的预测，该理论旨在了解不同的浮游动物物种如何再生食物中存在的氮和磷。因此，通过改变这些食草性浮游动物的动态，鱼类捕食可以影响氮和磷的循环。总部设在加拿大实验湖地区的主要研究方法将涉及对湖泊大型围栏中的营养物质和浮游动物的实验操作，以及对食物网结构的全湖操作(通过将梭鱼引入两个缺乏这种食鱼物种的湖泊)。这些研究直接应用于理解控制生态系统中元素循环的过程；这些过程在直接社会的各个领域发挥着关键作用，包括全球气候变化、环境中污染物的动态变化和水资源的退化。