EAPSI: Constraining the Isotope Effect of Denitrification to Improve Global Models of N Fluxes

EAPSI：限制反硝化的同位素效应以改进氮通量的全局模型

• 批准号: 1714064
• 负责人: Rebecca Walker
• 金额: $ 0.54万
• 依托单位: Walker Rebecca H
• 依托单位国家: 美国
• 项目类别: Fellowship Award
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-06-01 至 2018-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1714064&HistoricalAwards=false
• 关键词: EAPSI; Constraining; Isotope; Effect; Denitrification

This project will use modeling to quantify the amount of nitrogen lost from soils through denitrification, a key component of the nitrogen cycle. Quantifying denitrification is important because the gases produced during denitrification cause poor air quality that damages human health. Also, because nitrogen limits the ability of plants to grow, quantifying it will allow for better predictions about carbon storage. Denitrification is nearly impossible to measure directly, and as such, developing an accurate model is essential. This project will be conducted at the Commonwealth Scientific and Industrial Research Organization (CSIRO) in Australia under the mentorship of Dr. Ying-Ping Wang. The collaboration provides access to the expertise and computing capacity at CSIRO. Denitrification removes biologically available nitrogen (N) from ecosystems, making it an important control over the biosphere's N balance, with implications for air quality, human health, and climate change. Despite its importance, estimates of the global soil denitrification flux remain highly uncertain. Major challenges lie in directly measuring the gaseous by-products of denitrification and scaling this complex microbial processes. Process-based models constrained by empirical isotopic evidence have emerged as a method to help overcome these challenges. However, the robustness of this method is limited by incomplete understanding of isotopic expression of denitrification and how it varies across known controls, such as carbon and nitrate availability and soil moisture and temperature. The project will determine how the isotopic expression of denitrification varies across a range of environmental controls and will incorporate this data into models of denitrification. Ultimately this model will be incorporated into the CASA-CNP, the global model of nutrient limitations on terrestrial carbon sequestration developed by scientists at CSIRO. This will reduce a key uncertainty in predictions of carbon sequestration. This award, under the East Asia and Pacific Summer Institutes program, supports summer research by a US graduate student and is jointly funded by NSF and the Australian Academy of Science.

该项目将使用建模来量化土壤中损失的氮量，这是硝化量，这是氮循环的关键组成部分。量化反硝化很重要，因为在反硝化过程中产生的气体会导致空气质量差会损害人类健康。同样，由于氮限制了植物生长的能力，因此量化它将可以更好地预测碳储存。硝化几乎不可能直接测量，因此，开发准确的模型至关重要。该项目将在Ying-Ping Wang博士的指导下在澳大利亚的英联邦科学和工业研究组织（CSIRO）进行。该协作可访问CSIRO的专业知识和计算能力。反硝化消除了生态系统中生物学上可用的氮（N），使其成为对生物圈N平衡的重要控制，对空气质量，人类健康和气候变化的影响。尽管它的重要性，但对全球土壤反硝化通量的估计仍然高度不确定。主要挑战在于直接测量硝化的气态副产品并扩展这种复杂的微生物过程。受经验同位素证据限制的基于过程的模型已成为帮助克服这些挑战的方法。但是，这种方法的鲁棒性受到对同位素表达的不完全理解的硝化表达及其在已知控制中的变化，例如碳和硝酸盐的可用性以及土壤水分和温度。该项目将确定反硝化的同位素表达如何在一系列环境控制中变化，并将这些数据纳入硝化模型。 最终，该模型将纳入CASA-CNP，这是CSIRO科学家开发的陆生碳固存的全球营养限制模型。这将减少碳固存预测的关键不确定性。在东亚和太平洋夏季学院计划下，该奖项支持美国一名研究生的夏季研究，并由NSF和澳大利亚科学院共同资助。