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: 1260692
• 负责人: Douglas Hammond
• 金额: $ 42.12万
• 依托单位: University of Southern California
• 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 2017-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1260692&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.

海洋生物泵是人为二氧化碳从大气中封存并作为有机碳输出到深海的主要途径之一。 虽然上升流区域的养分供应与高初级生产力之间的联系已得到充分证实，但控制上升流生态系统有机碳输出效率的因素尚不清楚。 南加州大学和波莫纳学院的科学家计划确定控制生物生产两个组成部分——净社区生产（NCP）和总初级生产（GPP）——以及颗粒有机碳出口效率——的速率和大小的因素。 ，在圣佩德罗海洋时间系列中，这是加州边境的一个沿海地点，在两年的时间里上升流速度极小和很高。 在这个地点，过去和正在进行的水文学和碳雨观测将为解释工作结果和机制提供历史背景。 将使用溶解氧与氩气 (O2/Ar) 的比率以及溶解氧 (O2) 的氧三重同位素组成来量化不同上升流强度下的 NCP 和 GPP 速率。 有机碳的输出将利用水体中的 234Th（钍）剖面，结合漂浮沉积物捕集器的部署以及水体碳同位素平衡的开发来建立。 将使用大气 7Be（铍）输入的非稳态预算及其深度积分衰变来表征上升流，并根据风应力旋度的远程测量和溶解的无机碳和硅的预算来估计速率。 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积分剖面，以评估上升流对混合层输入的影响以及在上升流季节性转变期间使用非稳态模型。 所获得的综合数据集应有助于了解不同上升流情况下的有机碳输出效率，并有助于将基于卫星的叶绿素测量与这些高产生态系统的有机碳输出联系起来。更广泛的影响：一名研究生和一名本科生作为该项目的一部分，南加州大学的学生和波莫纳学院的两名本科生将得到支持和培训。