Collaborative Research: Southeast Pacific and Southern Ocean Seawater Isotopes Determined from US GEOTRACES GP17-OCE and GP17-ANT Samples

合作研究：从美国 GEOTRACES GP17-OCE 和 GP17-ANT 样品中测定东南太平洋和南大洋海水同位素

• 批准号: 2049577
• 负责人: Elisabeth Sikes
• 金额: $ 30.68万
• 依托单位: Rutgers University New Brunswick
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-07-01 至 2024-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2049577&HistoricalAwards=false
• 关键词: Collaborative; Research; Southeast; Pacific; Southern

The stable isotopic composition of the oxygen atom in seawater (d18O) is controlled by evaporation, precipitation, and riverine or glacial meltwater input. Most of the deep interior water masses in the ocean are formed or modified in the Southern Ocean and sink to fill the deep layers that circulate throughout the world’s oceans. The d18O signatures in seawater can be used as tracers for these sub-surface water masses once they sink to depth. The Southern Ocean and South Pacific are critical locations for water mass formation and thus, for understanding global overturning circulation, carbon cycling and climate dynamics. However, data on the d18O of seawater, particularly in the sub-surface, is virtually nonexistent for the South Pacific and Southern Ocean. Moreover, our understanding of past temperature and oceanic processes based on the d18O signature in marine carbonates (e.g. corals and foraminifera) have relied on the assumption that variations in the oxygen isotopic composition of the sub-surface water masses are nominal through time, which can be directly tested on a wider basis using new technologies during this project. Investigators will conduct analyses of seawater d18O from samples collected from depth transects during the US GEOTRACES science expedition to the South Pacific (GP17-OCE) and the Amundsen Sea sector of the Antarctic continental margin (GP17-ANT). This ocean region is of particular significance because it is experiencing rapid environmental changes in the past few decades, including the fastest melting of ice shelves around the entire Antarctic. This project will support the development of diverse involvement in teaching and outreach efforts in a primarily undergraduate and Hispanic serving institution. The outreach activities will provide ample opportunities to engage students from underrepresented groups in both formal and informal settings. It is well-established from first principles that d18O and d2H of seawater have a positive relationship to salinity, but regional variations in the isotopic relationship of seawater to salinity are poorly constrained. Temperature reconstructions relying on d18O in calcite microfossils biologically precipitated in equilibrium with seawater and preserved in marine sediments are only quantitative if the seawater d18O (d18Osw) in which that carbonate was precipitated is known. Despite the reliance of these paleo-estimations on the d18O of modern seawater, surface measurements are few and far between and sub-surface data in the South Pacific and Southern Oceans is even more limited. Filling this fundamental gap in data to quantify the influence of precipitation, evaporation and glacial melt water on the d18O and d2H of interior seawater masses is globally relevant to our understanding of ocean circulation and broader climate dynamics. The development and improvement of new laser-based spectroscopy techniques such as off-axis integrated cavity output spectroscopy (OA-ICOS) and cavity ring-down spectroscopy, allows for seawater d18O and d2H analyses to be run quickly and cost effectively compared to traditional IRMS (Isotope Ratio Mass Spectrometry). A core aim of this project is to compare and contrast IRMS and OA-ICOS analyses to address accuracy, precision and offsets between methods. Obtaining d18Osw directly contributes to the GP17-OCE stated aims of characterizing near- and far-field trace element and isotope (TEI) inputs and to the GP17-ANT stated aims of quantifying gradients in TEI distributions and characterizing, glacial meltwater inputs in the Amundsen Sea and Southern Ocean.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

海水中tomygen原子的稳定同位素组成（D18O）由蒸发控制，河流或冰川融化了大部分海洋中的大部分深层内部水质量在南大洋中形成或修改，并沉入地下，以填充它们的深层，以填充它们的深层。循环世界的海洋可以使南太平洋南部和南太平洋的深度陷入困境。对于南太平洋和南大洋是不存在的。尽管可以直接对研究者进行测试的时间将从美国地理位置scitis pacions toe toe toe toe toe toe toe to to s oth Pacific（GP17-OCE）和南极大陆边缘的Amundsen Sea部门（GP17-ANT）具有特殊意义，因为它在过去的几十年中的发展变化，这项项目将发展各种各样的互动，并在主要的duate和西班牙裔服务学院中宣传。正式的环境是从第一个原则中建立的，即D18O和D2H与海水与盐度的盐度关系有积极的关系。 D18OSW）已知这些碳酸盐是对这些古估计的依赖于现代海水的D18O，在南太平洋和南部海洋中的地下数据较远数据中的这一基本差距是量化与我们对海洋循环和降落的理解以及改善新的新型激光光谱技术的降水，蒸发和冰川熔体对D18O和D2H的影响。 - 轴整合的腔体输出光谱（OA-ICOS）和腔戒指光谱，使海水D18O和D2H分析可以快速运行，并且比较了PEAT的传统PE比率质谱。 IRMS和OA-ICOS分析以解决方法之间的准确性，精度和偏移。南方。这一奖项反映了NSF'SFly的使命和Beendydydydydydydydydydydydydydydydydydydydydydydydydydydydydydydydydydydydydydydydydydydydydydydydydydydydydydydydydydydydydydydydydydy the Issualition使用基金会的知识分子优点和更广泛的影响评论标准。