Dissertation Research: Closing the nitrogen budget: Quantifying denitrification in an arid ecosystem undergoing nitrogen enrichment

论文研究：关闭氮预算：量化经历氮富集的干旱生态系统中的反硝化

• 批准号: 1309124
• 负责人: Jed Sparks
• 金额: $ 2.08万
• 依托单位: Cornell University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-07-01 至 2015-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1309124&HistoricalAwards=false
• 关键词: Dissertation; Research; Closing; nitrogen; budget

Adding reactive nitrogen, from fertilizer, deposition, or nitrogen fixing plants, to ecosystems can cause rapid and often detrimental changes considered undesirable by humans. The creation of dinitrogen gas (N2) through a process called denitrification is the primary mechanism that removes reactive nitrogen from an ecosystem. However, this process can also produce nitrous oxide (N2O), a greenhouse gas. Therefore, understanding how much N2 versus N2O is produced during denitrification is critical to understanding both climate and ecosystem nutrient balance. One of the challenges of studying denitrification in the real world is that it is very difficult to measure the production of N2 in the field. The work proposed here will take advantage of a new lab measurement technique to measure the production of N2 from soils and examine how denitrification, N2 and N2O production and nitrogen cycling change after the expansion of a nitrogen-fixing trees into an arid subtropical grassland.Arid lands occupy nearly a third of the Earth's surface and support large human populations, so understanding the processing of nitrogen in these systems is important for future land use and global climate management. This project will provide the first estimate of the N2 loss occurring during denitrification in an arid system nitrogen cycle, and help to refine a method that can then be applied to other sites and ecosystems. The primary research site used in this project is an active cattle ranch in Southern Texas that is regularly visited by students, land managers and nature enthusiasts. This project will take advantage of this public interface to educate on the effects and importance of human-driven landscape changes on ecosystem nutrient cycling.

向生态系统添加来自肥料、沉积或固氮植物的活性氮可能会导致人类不希望发生的快速且往往有害的变化。通过反硝化过程产生氮气 (N2) 是从生态系统中去除活性氮的主要机制。然而，这个过程也会产生一氧化二氮（N2O），一种温室气体。因此，了解反硝化过程中产生的 N2 与 N2O 的量对于了解气候和生态系统养分平衡至关重要。在现实世界中研究反硝化的挑战之一是很难在现场测量氮气的产生。这里提出的工作将利用一种新的实验室测量技术来测量土壤中氮的产生，并研究固氮树木扩展到干旱的亚热带草原后反硝化、N2和N2O的产生以及氮循环的变化。干旱土地占据地球表面的近三分之一并养活了大量人口，因此了解这些系统中氮的处理对于未来的土地利用和全球至关重要。 气候管理。该项目将首次估计干旱系统氮循环反硝化过程中发生的氮损失，并有助于完善一种可应用于其他地点和生态系统的方法。该项目使用的主要研究地点是德克萨斯州南部的一个活跃的养牛场，学生、土地管理者和自然爱好者定期参观该牧场。该项目将利用这个公共界面来教育人类驱动的景观变化对生态系统养分循环的影响和重要性。