Collaborative Research: Use of Triple Oxygen Isotopes and O2/Ar to constrain Net/Gross Oxygen Production during upwelling and non-upwelling periods in a Coastal Setting

合作研究：使用三重氧同位素和 O2/Ar 来限制沿海地区上升流和非上升流期间的净/总氧气产量

• 批准号: 1260296
• 负责人: Maria Prokopenko
• 金额: $ 22.87万
• 依托单位: Pomona College
• 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: 2013-04-15 至 2018-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1260296&HistoricalAwards=false
• 关键词: Collaborative; Research; Use; Triple; Oxygen

The marine biological pump is one of the primary pathways via which anthropogenic carbon dioxide may be sequestered from the atmosphere and exported to the deep ocean as organic carbon. While the link between nutrient supply and high primary productivity in upwelling regions is well established, factors controlling the organic carbon export efficiency of upwelling ecosystems are not well known. Scientists from the University of Southern California and Pomona College plan to determine the factors that control the rates and magnitudes of two components of biological production, Net Community Production (NCP) and Gross Primary Production (GPP), as well as particulate organic carbon export efficiency, at the San Pedro Ocean Time Series, a coastal site in the California Borderland during periods of minimal and high upwelling velocity over a 2-year span. At this site, past and ongoing observations of hydrography and carbon rain will provide an historical context for interpreting results and mechanisms at work. Rates of NCP and GPP will be quantified at different upwelling intensity, using dissolved oxygen to argon (O2/Ar) ratios and the oxygen triple isotope composition of dissolved oxygen (O2). The export of organic carbon will be established using 234Th (thorium) profiles in the water column, coupled with floating sediment trap deployments, and the development of a carbon isotope balance for the water column. Upwelling will be characterized using non-steady state budgets for atmospheric 7Be (beryllium) input and its depth-integrated decay, as well as estimating rates based on remote measurements of wind stress curl and budgets for dissolved inorganic carbon and silicon. Application of the O2/Ar ratio and the oxygen triple isotope approach will require depth-integrated profiles of these tracers to evaluate the impact of upwelling on mixed layer inputs and use of non-steady state models during seasonal transitions in upwelling. The comprehensive data set to be obtained should provide insights into the organic carbon export efficiency under variable upwelling regimes and help to relate the satellite-based measurements of chlorophyll to the organic carbon export of these highly productive ecosystems.Broader Impacts: One graduate and one undergraduate student from the University of Southern California and two undergraduate students from Pomona College would be supported and trained as part of this project.

海洋生物泵是人类活动产生的二氧化碳从大气中分离出来并作为有机碳输出到深海的主要途径之一。 虽然营养供应和高初级生产力之间的联系，在上升流地区是公认的，控制上升流生态系统的有机碳输出效率的因素还不为人所知。 来自南加州大学和波莫纳学院的科学家计划在圣佩德罗海洋时间序列中确定控制生物生产的两个组成部分，净社区生产（NCP）和总初级生产（GPP）以及颗粒有机碳出口效率的速率和幅度的因素，加州边界的一个沿海站点，在2年的时间跨度内，上升流速度最小和最高。 在这个网站上，过去和正在进行的水文和碳雨观测将提供一个历史背景下解释的结果和机制的工作。 NCP和GPP率将在不同的上升流强度，使用溶解氧氩（O2/Ar）比和溶解氧（O2）的氧三重同位素组成进行量化。 将利用水柱中的234 Th（钍）剖面，加上漂浮沉积物捕集器的部署，以及水柱碳同位素平衡的建立，来确定有机碳的输出。 上升流的特点是使用非稳态预算的大气7 Be（铍）输入和其深度综合衰减，以及估计率的基础上远程测量风应力旋度和预算溶解无机碳和硅。O2/Ar比和氧三重同位素方法的应用将需要这些示踪剂的深度集成配置文件，以评估混合层输入和使用非稳态模型在上升流的季节性转换的上升流的影响。 将获得的综合数据集应有助于深入了解各种上升流情况下的有机碳输出效率，并有助于将卫星叶绿素测量结果与这些高产生态系统的有机碳输出联系起来。南加州大学的一名研究生和一名本科生以及波莫纳学院的两名本科生将得到支持和培训，这个项目