Nitrous oxide cycling in the Western Arctic Ocean from stable isotopic and concentration data

根据稳定同位素和浓度数据了解北冰洋西部的一氧化二氮循环

• 批准号: 1603596
• 负责人: Annie Bourbonnais
• 金额: $ 29.06万
• 依托单位: University of Massachusetts, Dartmouth
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-07-01 至 2019-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1603596&HistoricalAwards=false
• 关键词: Nitrous; oxide; cycling; Western; Arctic

Nitrous oxide is a potent greenhouse gas in the troposphere and an ozone-depleting substance in the stratosphere, yet its sources and sinks in the ocean are neither well-quantified nor well understood. Nitrous oxide is both produced and consumed by microbial processes; it is produced by different processes dependent upon the amount of oxygen present locally. The Arctic Ocean may represent an important source of nitrous oxide to the atmosphere. High nitrous oxide saturations were recently observed in productive shallow Arctic shelf waters. The proposed research will test the hypotheses that productive shelf regions of the Western Arctic Ocean (e.g., Chukchi and Beaufort seas) stimulates nitrous oxide production and contributes to offshore transport of nitrous oxide toward the central Arctic. Besides developing an important baseline data set for the Arctic science community, this project will contribute to STEM workforce development in numerous manners. It will support an early-career female scientist during the formative years of her career. It will provide summer educational research opportunities to undergraduate students. It will develop seminars for elementary school teachers and provide short classroom presentations at a local public school and contribute to an afterschool non-profit effort devoted to providing high quality educational programs to at risk youth.The primary goal of this proposed research is to evaluate nitrous oxide cycling in the Western Arctic Ocean from its concentrations, stable isotopes and isotopomers. The project will use isotopic and isotopomer measurements from both shelf and offshore waters to constrain estimates of nitrous oxide cycling in the Arctic. The data will be used to evaluate 1) the pathways of nitrous oxide production from either nitrification following organic matter decomposition in the water column or coupled nitrification-denitrification in the sediments and 2) how these processes influence nitrous oxide exchanges between the surface layer and the atmosphere. Comparisons of observations at coastal and shelf stations in the Bering and Chukchi seas with those offshore in the Deep Canadian Basin will allow the evaluation of the effects of mixing and long-range transport on geochemical signals. The measurements will also serve as a baseline for future assessment of change. The project profits from leveraging of other investments by NSF and the principal investigators? international collaborators, benefitting from measurements and samples collected during the U.S. GEOTRACES Arctic section and the 2016 CHINARE Arctic cruises.

一氧化二氮在对流层是一种强效温室气体，在平流层是一种臭氧消耗物质，但其在海洋中的来源和汇既没有很好的量化，也没有很好的理解。一氧化二氮是由微生物过程产生和消耗的;它是由不同的过程产生的，取决于当地存在的氧气量。北冰洋可能是大气中一氧化二氮的重要来源。最近在北极浅海沃茨水域观察到高的一氧化二氮饱和度。拟议的研究将检验以下假设：北冰洋西部的生产性大陆架区域（例如，楚科奇海和博福特海）刺激了一氧化二氮的产生，并有助于一氧化二氮向北极中部的近海运输。除了为北极科学界开发重要的基线数据集外，该项目还将以多种方式促进STEM劳动力的发展。 它将在职业生涯的形成期为一名职业生涯早期的女科学家提供支持。 它将为本科生提供暑期教育研究机会。 它将为小学教师举办研讨会，并在当地公立学校提供简短的课堂演示，并为一个致力于为风险青少年提供高质量教育计划的课外非营利努力做出贡献。这项拟议研究的主要目标是从其浓度，稳定同位素和同位素异构体评估北冰洋西部的一氧化二氮循环。该项目将利用大陆架和近海沃茨的同位素和同位素异构体测量结果来限制对北极一氧化二氮循环的估计。这些数据将用于评估1）一氧化二氮产生的途径，无论是在水体中有机物分解后的硝化作用，还是沉积物中的硝化-反硝化作用，以及2）这些过程如何影响表层和大气之间的一氧化二氮交换。将白令海和楚科奇海沿海和大陆架观测站的观测结果与加拿大深海盆地近海观测结果进行比较，将有助于评估混合和远距离迁移对地球化学信号的影响。这些测量结果还将作为今后评估变化的基线。 该项目的利润来自NSF和主要研究者的其他投资？国际合作者，受益于在美国GEOTRACES北极部分和2016年北极巡航期间收集的测量和样本。