Collaborative Research: Physical and biological controls on ocean carbon and oxygen uptake in the western North Pacific

合作研究：北太平洋西部海洋碳和氧吸收的物理和生物控制

• 批准号: 2049631
• 负责人: Seth Bushinsky
• 金额: $ 87.44万
• 依托单位: University of Hawaii
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-09-01 至 2024-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2049631&HistoricalAwards=false
• 关键词: Collaborative; Research; Physical; biological; controls

Understanding the mechanisms that determine when and how the ocean takes up carbon from the atmosphere is important to our fundamental knowledge of ocean biogeochemistry and to our ability to model future climate. Air-sea fluxes of oxygen are also relevant to climatic variability, and surface oxygen can act as a tracer of biological carbon production and export as well as of important physical processes. The Kuroshio Extension region of the northwest Pacific Ocean is an area of strong carbon dioxide uptake and a site of wintertime watermass formation, with Subtropical Mode Water formed to the south of the Kuroshio Extension and lighter and denser Central Mode Water formed to the north. These mode waters then sink below the surface, moving carbon dioxide to the ocean interior. There are very few wintertime vertical profiles of any carbon system parameter in these mode water formation regions and no fully resolved winter or annual cycles of measurements. In this project, the investigators will deploy robotic profiling floats to make these needed measurements. They will combine the float data with numerical modeling to advance understanding of mode water formation and air-sea fluxes of carbon dioxide and oxygen in this important region. This proposal will fund an early career scientist and expand expertise in and capability for biogeochemical profiling float operations at the University of Hawai’i, providing a foundation for future work in autonomous biogeochemical platforms. This proposal will fund a graduate student in their Ph.D. work and multiple summer undergraduate researchers. Students will gain exposure to the complementary fields of marine chemistry, ocean physics, and climate models. The team will investigate carbon and oxygen budgets in the northwest Pacific from the following: new float observations of oxygen, nitrate, and estimated dissolved inorganic carbon; longer-term float temperature and salinity observations for water mass analysis; and model output. They will deploy biogeochemical Argo floats capable of measuring pH in the heart of the Subtropical and Central Mode Water formation regions in the Kuroshio Extension to provide vertical profiles of oxygen, nitrate, and, especially, estimates of dissolved inorganic carbon. They will use these observations to both calculate the drivers of air-sea carbon dioxide and oxygen fluxes and to validate model output for further analysis. Western boundary currents, such as the Kuroshio Extension, are areas of significant carbon dioxide uptake, but the relative importance of biology and physics to that uptake and its variability on large temporal and spatial scales is not well understood. The project has three main goals: (1) to determine what fraction of the CO2 and O2 uptake in the North Pacific is the result of mode water formation and subduction, (2) to determine how the physical and biological processes that drive air-sea fluxes vary spatially in the Kuroshio Extension region, and (3) to analyze the drivers of interannual and decadal variability of mode water formation and related gas fluxes in the Kuroshio Extension region and determine how that variability is linked to the larger climate system. The new observations will be evaluated in the larger context of multiple decades of observations from ships and almost two decades of physical observations from profiling floats. The team will use model output to diagnose physical drivers of air-sea fluxes and to link the observed mechanisms to longer-term variability and climate processes. The data collected will represent the first seasonally resolved profiles of oxygen, nitrate, and derived DIC in a western boundary current and will be of use to a broad community of researchers. This project is jointly funded by the Chemical Oceanography Program, the Physical Oceanography Program, and the Established Program to Stimulate Competitive Research (EPSCoR).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.

了解决定海洋何时以及如何从大气中吸收碳的机制，对于我们对海洋生物地球化学的基本知识以及我们对未来气候进行建模的能力非常重要。海-气氧通量也与气候变异性有关，表面氧可作为生物碳生产和输出以及重要物理过程的示踪剂。西北太平洋黑潮延伸区是二氧化碳吸收强烈的区域和冬季水团形成的场所，黑潮延伸区以南形成副热带模式水，北部形成较轻、密度较大的中心模式水。这些模式的水然后沉入海面以下，将二氧化碳移动到海洋内部。在这些模式水形成区，几乎没有任何碳系统参数的冬季垂直剖面，也没有完全分辨的冬季或年度测量周期。在这个项目中，调查人员将部署机器人剖面浮标来进行这些必要的测量。他们将把浮标数据与数值模拟相结合，以促进对这一重要区域的水形成模式以及二氧化碳和氧气的海气通量的理解。这项提议将资助一名早期职业科学家，并扩大夏威夷大学生物地球化学剖面浮选作业的专门知识和能力，为自主生物地球化学平台的未来工作奠定基础。这项提案将为一名研究生的博士研究和多名暑期本科生研究人员提供资金。学生将接触到海洋化学、海洋物理和气候模型等互补领域。该小组将从以下方面调查西北太平洋的碳和氧收支：对氧、硝酸盐和估计的溶解无机碳的新的浮标观测；用于水团分析的较长期的浮标温度和盐度观测；以及模型输出。他们将部署生物地球化学ARGO浮标，能够测量黑潮延伸区副热带和中央模式水形成区中心的pH值，以提供氧、硝酸盐的垂直剖面，特别是估计溶解的无机碳。他们将使用这些观测来计算海-气二氧化碳和氧气通量的驱动因素，并验证模型输出以供进一步分析。西部边界流，如黑潮延伸区，是大量吸收二氧化碳的地区，但生物学和物理学对这种吸收的相对重要性及其在大的时间和空间尺度上的变异性还没有得到很好的了解。该项目有三个主要目标：(1)确定北太平洋二氧化碳和O2吸收的多大比例是模水形成和俯冲的结果；(2)确定驱动黑潮延伸区海气通量的物理和生物过程如何在空间上发生变化；(3)分析黑潮延伸区模水形成和相关气体通量年际和年代际变化的驱动因素，并确定这种变化如何与更大的气候系统相联系。新的观测将在更大的背景下进行评估，包括数十年的船舶观测和近20年的浮标剖面物理观测。该团队将使用模型输出来诊断海-气通量的物理驱动因素，并将观察到的机制与较长期的可变性和气候过程联系起来。收集的数据将代表西部边界流中氧、硝酸盐和衍生的DIC的第一个季节解析剖面，并将对广泛的研究人员社区有用。该项目由化学海洋学计划、物理海洋学计划和已建立的激励竞争研究计划(EPSCoR)共同资助。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。