Nitrogen isotope fractionation and geological nitrogen cycle

氮同位素分馏和地质氮循环

基本信息

批准号：
419380-2012
负责人：
Li, Long
金额：
$ 2.04万
依托单位：
University of Alberta
依托单位国家：
加拿大
项目类别：
Discovery Grants Program - Individual
财政年份：
2017
资助国家：
加拿大
起止时间：
2017-01-01 至 2018-12-31
项目状态：
已结题

来源：
https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=634051
关键词：
Nitrogen isotope fractionation geological nitrogen

项目摘要

Light stable isotopes have become a routine and robust tool to trace material sources and monitor (bio)geochemical processes in planetary and geosciences. For example, carbon isotopes have been used to examine the carbon cycle in various temporal and spatial scales on the Earth. This effort has significantly advanced our understanding of the evolution of and interaction between the Earth's mantle, crust, and particularly atmosphere, in which the level of greenhouse gas CO2 directly impacts the climate and environment. In striking contrast, the cycle of nitrogen, a component equally important as carbon in all Earth's reservoirs, is still poorly understood even though several of its species (NH3, N2O, N2) also act as greenhouse gases. This has been mainly attributed to (1) the poor knowledge of nitrogen isotope effects in key processes controlling nitrogen transfer and siting at different pressure-temperature conditions and (2) poorly constrained boundary conditions to define the nitrogen properties of different reservoirs.To fill this gap, this Discovery Program has two objectives:(1) use laboratory- and field-based investigations to determine the nitrogen isotope fractionations between different nitrogen species at a variety of temperatures related to important nitrogen cycling processes, such as abiotic nitrogen reduction, ammonium-ammonia transformation, ammonia degassing, and ammonium exchange between minerals.(2) clarify the uncertainties in the study of large-scale nitrogen cycling across subduction zones, including characterizing the nitrogen behavior in early subduction and detecting the recycled crustal nitrogen in arc volcanic rocks and their contributions to the global geological nitrogen cycle.

光稳定同位素已成为行星和地球科学中追踪材料来源和监测（生物）地球化学过程的常规且强大的工具。例如，碳同位素已被用来检查地球上不同时间和空间尺度的碳循环。这项工作极大地增进了我们对地幔、地壳，特别是大气的演化和相互作用的理解，其中温室气体二氧化碳的水平直接影响气候和环境。与此形成鲜明对比的是，尽管氮的几种物质（NH3、N2O、N2）也充当温室气体，但人们对氮的循环仍然知之甚少，氮是地球所有储库中与碳同等重要的成分。这主要归因于（1）对控制氮转移的关键过程和在不同压力-温度条件下选址的氮同位素效应了解甚少；（2）定义不同储层氮性质的边界条件约束较差。差距，该发现计划有两个目标：（1）利用实验室和现场调查来确定与重要氮循环过程相关的不同温度下不同氮物种之间的氮同位素分馏，例如非生物氮还原， (2)澄清俯冲带大规模氮循环研究中的不确定性，包括表征俯冲早期的氮行为和探测弧火山中再循环的地壳氮岩石及其对全球地质氮循环的贡献。