Measurements of stable carbon isotopes on board GO-SHIP cruises in the South Atlantic Ocean to enhance our ability to quantify anthropogenic CO2 uptake rates by the ocean

在南大西洋 GO-SHIP 游轮上测量稳定碳同位素，以增强我们量化海洋人为二氧化碳吸收率的能力

• 批准号: 2123768
• 负责人: Wei-Jun Cai
• 金额: $ 70.21万
• 依托单位: University of Delaware
• 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: 2021-09-01 至 2025-08-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2123768&HistoricalAwards=false
• 关键词: Measurements; stable; carbon; isotopes; board

Rising carbon dioxide concentrations in the atmosphere, global climate change, and the sustainability of the Earth’s biosphere are of great scientific and societal concern. Approximately one-quarter of fossil fuel emissions of carbon dioxide emitted each year are absorbed by the oceans, and it is important to understand where and how fast this process occurs. Stable isotopes of carbon can be used as a “signature” to identify fossil fuel-derived carbon dioxide in the atmosphere and ocean. The investigators have developed a new method for measuring the stable carbon isotope composition of dissolved carbon dioxide rapidly and precisely while at sea. They will measure several thousand samples on two research expeditions to the South Atlantic Ocean. They will compare their measurements to ones made in the same locations approximately ten years earlier, and determine the amount of carbon dioxide absorbed over that time period. The proposed research will enhance ocean carbon research infrastructure, general science education, and public awareness of climate change and environmental issues. The investigators plan to enhance diversity in earth sciences by recruiting underrepresented minority students in the research and have a graduate and an undergraduate student involved in all phases of this project. The team, including the students, will actively disseminate the research results in international, national, regional, local education and outreach activities, and in peer-review journals. In the South Atlantic Ocean, anthropogenic CO2 uptake rates are high and variable as mode and intermediate waters are formed and are sensitive to climate changes. The carbon-13 Suess effect makes delta13C-CO2 in the atmosphere a clearly defined endmember and delta13C-DIC in the ocean a powerful tracer to independently estimate anthropogenic CO2 uptake and storage in the ocean. The team has developed a precise, rapid, and sea-going method to simultaneously measure dissolved inorganic carbon (DIC) concentration (to plus or minus 2 micromol per kilogram) and stable carbon isotope composition (delta13C-DIC) (to plus or minus 0.03 permil) by combining a CO2 extraction device with a Cavity Ring-Down Spectroscopy (CRDS) isotope analyzer. They will use this method aboard GO-SHIP cruises A13.5 and A16S to analyze about 1000 samples onboard the ship and 2000 samples on land for each cruise. Extensive evaluation and comparison of this method with the traditional isotope ratio mass spectrometry (IRMS)-based method will be done. The PIs hypothesize that the formation and the strength of mode and intermediate waters have a strong influence on the lateral transport of anthropogenic carbon and thus the decadal variability of the water column anthropogenic carbon inventory change. As a result, the change in inventory has both meridional and zonal trends, and therefore a combination of A13.5 and A16S will better represent the basin-wide changes. Two objectives will be achieved in testing this hypothesis: (1) Demonstrate that precise and accurate delta13C-DIC data, comparable in quality to IRMS-based data, can be collected via the CRDS-based method, and that large numbers of samples can be analyzed onboard ships and back home with high spatial resolution comparable to other GO-SHIP level 1 parameters such as DIC; (2) Assess the spatial variations and temporal changes of the anthropogenic carbon uptake and storage rates in the South Atlantic Ocean. In particular, the PIs will compare estimated anthropogenic carbon inventories independently from delta13C-DIC and DIC observations from transect A13.5 (2022 vs. 2010 and earlier data) in the eastern basin with those of transect A16S (2024 vs. 2013 and earlier data) in the western basin. They will also compare the basin-wide water column anthropogenic 13C-DIC inventory with the surface ocean anthropogenic 13CO2 uptake flux estimated from air-sea carbon isotope disequilibrium, the difference being anthropogenic carbon carried by lateral transport.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.

大气中二氧化碳浓度的上升、全球气候变化以及地球生物圈的可持续性引起了科学和社会的极大关注，每年排放的化石燃料二氧化碳中约有四分之一被海洋吸收。了解这一过程发生的地点和速度很重要，可以使用碳的稳定同位素作为识别大气和海洋中化石燃料产生的二氧化碳的“特征”。研究人员开发了一种测量稳定碳的新方法。他们将在两次南大西洋研究考察中快速准确地测量溶解二氧化碳的同位素成分，并将其测量结果与大约十年前在同一地点进行的测量结果进行比较，并确定含量。拟议的研究将加强海洋碳研究基础设施、普通科学教育以及公众对气候变化和环境问题的认识。研究人员计划通过招募代表性不足的少数族裔学生来参与研究，以增强地球科学的多样性。并有一名研究生和一名本科生参与该项目的所有阶段，包括学生在内，将在国际、国家、区域、地方教育和推广活动以及同行评审期刊中积极传播研究成果。随着模式水和中间水的形成，碳13 Suess 效应使大气中的 delta13C-CO2 成为明确定义的端元，而海洋中的 delta13C-DIC 成为独立的强大示踪剂。该团队开发了一种精确、快速的海上方法来估计海洋中的人为二氧化碳吸收和储存，以同时测量溶解无机碳（DIC）浓度（每公斤正负2微摩尔）和稳定碳同位素组成（ delta13C-DIC）（正负 0.03 permil），通过将 CO2 提取装置与光腔衰荡光谱 (CRDS) 同位素分析仪相结合。他们将使用这种方法。将在 GO-SHIP 邮轮 A13.5 和 A16S 上分析每次邮轮上约 1000 个船上样本和陆地上 2000 个样本，并将对该方法与基于传统同位素比质谱 (IRMS) 的方法进行广泛的评估和比较。 PI们认为，模式水和中间水的形成和强度对人为碳的横向输送以及人为水体的年代际变化有很大影响。因此，库存变化既有经向趋势，也有纬向趋势，因此 A13.5 和 A16S 的组合将更好地代表流域范围内的变化：（1） ) 证明可以通过基于 CRDS 的方法收集精确且准确的 delta13C-DIC 数据，其质量与基于 IRMS 的数据相当，并且可以在船上和回国以可比的高空间分辨率分析大量样本与其他 GO-SHIP 1 级参数（例如 DIC）相比较； (2) 评估南大西洋人为碳吸收和储存速率的空间变化和时间变化，特别是，PI 将独立于 delta13C 来比较估计的人为碳库存。 -东部盆地A13.5断面（2022年对比2010年及更早数据）的DIC和DIC观测值以及A16S断面（2024年对比2010年及更早数据）的DIC和DIC观测结果他们还将西部流域的全流域水柱人为 13C-DIC 库存与根据海气碳同位素不平衡估计的表层海洋人为 13CO2 吸收通量进行比较，差异在于侧流携带的人为碳。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

Ocean ventilation controls the contrasting anthropogenic CO2 uptake rates between the western and eastern South Atlantic Ocean basins

海洋通风控制南大西洋盆地西部和东部之间的人为二氧化碳吸收率对比

• 发表时间: 2022-06
• 期刊: Global biogeochemical cycles
• 影响因子: 5.2
• 作者: Gao, H.;W.;M. Jin;C. Dong;A. H. V Timmerman
• 通讯作者: A. H. V Timmerman

Ocean Ventilation Controls the Contrasting Anthropogenic CO 2 Uptake Rates Between the Western and Eastern South Atlantic Ocean Basins

海洋通风控制南大西洋盆地西部和东部的人为 CO 2 吸收率对比

• DOI: 10.1029/2021gb007265
• 发表时间: 2022-06
• 期刊: Global Biogeochemical Cycles
• 影响因子: 5.2
• 作者: Gao, Hui;Cai, Wei‐Jun;Jin, Meibing;Dong, Changming;Timmerman, Amanda H. V.
• 通讯作者: Timmerman, Amanda H. V.

Performance evaluations and applications of a δ13C-DIC analyzer in seawater and estuarine waters

海水和河口水域中Ύ´13C-DIC分析仪的性能评估和应用

• DOI: 10.1016/j.scitotenv.2022.155013
• 发表时间: 2022-08
• 期刊: Science of The Total Environment
• 影响因子: 9.8
• 作者: Deng, Xue;Li, Qian;Su, Jianzhong;Liu, Chun;Atekwana, Eliot;Cai, Wei
• 通讯作者: Cai, Wei