Collaborative Research: RAPID: Quantifying and characterizing the origin of Arctic Ocean methane from the Alaska continental shelf to the North Pole

合作研究：RAPID：量化和表征从阿拉斯加大陆架到北极的北冰洋甲烷的来源

• 批准号: 2226223
• 负责人: Cédric Magen
• 金额: $ 10.44万
• 依托单位: University of Maryland, College Park
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-06-01 至 2025-05-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2226223&HistoricalAwards=false
• 关键词: Collaborative; Research; RAPID; Quantifying; characterizing

Methane is relatively rare in Earth’s atmosphere but plays a significant role in the global carbon cycle and climate change. It is therefore key to better understand the distribution and behavior of natural sources of methane emissions and how both may change in an evolving climate. In the Arctic, large reservoirs of methane are currently trapped as permafrost (frozen soil) or gas hydrates (an ice-like substance that contains methane in its structure) on Arctic Ocean continental shelves. As the Arctic warms, permafrost and gas hydrates may degrade, releasing more methane to the atmosphere. This project, part of the United States’ contribution to the international Synoptic Arctic Survey (SAS), is determining whether rates of Arctic methane release from those natural sources are being affected by the present warming by measuring methane in Arctic Ocean from northern Alaska to the North Pole. The team is focusing especially on how much methane released from the seafloor reaches the water surface and adds to atmospheric methane. The team is sharing methane data and other results with the larger US SAS effort and teaching community college students about seagoing research methods and climate change. This project is testing the hypothesis that a warming Arctic Ocean may have accelerated the release of methane from permafrost and gas hydrate dissociation in shelf and slope sediments. The research team is measuring water column dissolved methane concentrations and stable isotopologues, as well as continuous measurements of methane in air underway along a transect from the Alaska Shelf northward. The team members are investigating the sources and processes controlling the presence of methane using methane 13C and 2H stable isotopes. Clumped isotopes of methane in air are being analyzed on selected samples identified as possible methane endmembers in the Arctic system. The project is a US contribution to the international Synoptic Arctic Survey (SAS) and is providing a baseline for measurements in the future of Arctic conditions. The measurement of the stable isotope 2H-CH4 in the Arctic Basin is the first performed in deep Arctic waters and is greatly improving our understanding of the Arctic methane cycle.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.

甲烷在地球大气中相对稀少，但在全球碳循环和气候变化中发挥着重要作用，因此，改善甲烷排放自然来源的分布和行为以及两者在北极气候变化中的变化至关重要。随着北极变暖，北冰洋大陆架上的大量甲烷目前以永久冻土（冻结的土壤）或天然气水合物（一种结构中含有甲烷的冰状物质）的形式被困住。天然气水合物可能会降解，向大气中释放更多甲烷。该项目是美国对国际北极天气调查（SAS）贡献的一部分，正在确定这些自然资源的北极甲烷释放率是否受到当前的影响。通过测量从阿拉斯加北部到北极的北冰洋的甲烷，该团队特别关注有多少甲烷从海底释放到水面并增加了大气中的甲烷含量。美国 SAS 致力于向社区大学生教授有关航海研究方法和气候变化的知识，该项目正在测试北冰洋变暖可能加速了永久冻土中甲烷的释放以及陆架和斜坡沉积物中天然气水合物的分解。测量水柱中溶解的甲烷浓度和稳定同位素体，以及沿着阿拉斯加陆架向北的横断面连续测量空气中的甲烷，团队成员正在调查控制甲烷存在的来源和过程。使用甲烷 13C 和 2H 稳定同位素对选定的样本进行分析，这些样本被确定为北极系统中可能的甲烷端元。该项目是美国对国际北极天气调查 (SAS) 的贡献，并提供基线。北极盆地稳定同位素 2H-CH4 的测量是首次在北极深水区进行的测量，这极大地增进了我们对北极盆地的了解。北极甲烷循环。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力优点和更广泛的影响审查标准进行评估，被认为值得支持。