Advanced Radiocarbon Dating and Molecular-Level Tools for Evaluating Marine Carbon Cycling in the Canadian Arctic

用于评估加拿大北极海洋碳循环的先进放射性碳测年和分子水平工具

• 批准号: RGPIN-2020-06501
• 负责人: Walker, Brett
• 金额: $ 2.55万
• 依托单位: University of Ottawa
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2021
• 资助国家: 加拿大
• 起止时间: 2021-01-01 至 2022-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=741256
• 关键词: Advanced; Radiocarbon; Dating; Molecular; Level

The marine carbon cycle plays an important role in regulating Earth's climate on timescales of years to millennia. The Canadian Arctic is warming at nearly double the rate as the rest of the planet, and as a result, Arctic seas will undergo unprecedented change in coming decades. These changes include: increased water temperatures, acidification and hypoxia that directly affect how ecosystems function. Marine carbon takes many forms, from large particulate detritus to small dissolved organic carbon (DOC) molecules and dissolved inorganic carbon salts (DIC; primarily as bicarbonate). This proposal aims to address fundamental knowledge gaps in our understanding of the Canadian Arctic marine carbon cycle. The proposed research will couple advanced stable carbon (13C) and radiocarbon (14C) isotopic measurements together with dissolved microbial biomarker analysis and nuclear magnetic resonance spectroscopy in order to quantify carbon sources, transformations and cycling rates within three Canadian Arctic regions: Baffin Bay, the Canadian Archipelago and Hudson Bay/Foxe Basin. The core research questions are: (1) What are the distributions and 14C-ages of marine DIC and DOC in the Canadian Arctic? (2) What are the residence times and ventilation ages of Canadian Arctic water masses? (3) What are the main sources of carbon persisting in these regions? and (4) to what extent does DOC biomolecular and chemical composition ultimately determine its biological availability to heterotrophic bacteria and its long-term persistence (i.e. 14C-age) in Arctic waters? These questions will be examined in field and lab-based studies conducted by 4 MSc students, 3 PhD students and 6-8 undergraduate students, recruited and trained using approaches designed to maximize equity, diversity and inclusion. Our results will advance our understanding of marine carbon cycling dynamics within the Canadian Arctic and improve our ability to predict carbon stocks and fluxes. This work will also help advance our ability to parametrize and incorporate DOC biogeochemical cycling into future Arctic Earth System Models. The research will take advantage of new and existing collaborations with world-renowned researchers within Canada and abroad. This research will integrate the use of two National Research Facilities, the André E. Lalonde Accelerator Mass Spectrometry Laboratory and Amundsen Science - further building Canada's profile as a leader in carbon cycle research in a period of rapid Arctic climate change. I have played a leading role in developing and improving marine 14C methods that have helped us quantify rates of organic carbon cycling in the ocean. My interdisciplinary background in the fields of chemical oceanography, isotope geochemistry, and accelerator mass spectrometry make me uniquely qualified to lead the proposed research program.

海洋碳循环在数年至数千年的时间尺度上对调节地球气候起着重要作用。加拿大北极地区的变暖速度几乎是地球其他地区的两倍，因此，北极海域将在未来几十年内发生前所未有的变化。这些变化包括：水温升高，酸化和缺氧，直接影响生态系统的功能。海洋碳有多种形式，从大颗粒碎屑到小溶解有机碳（DOC）分子和溶解无机碳盐（DIC;主要是碳酸氢盐）。该提案旨在解决我们在了解加拿大北极海洋碳循环方面的基本知识差距。拟议的研究将先进的稳定碳（13 C）和放射性碳（14 C）同位素测量与溶解的微生物生物标志物分析和核磁共振光谱结合在一起，以量化加拿大北极三个地区的碳源，转化和循环率：巴芬湾，加拿大群岛和哈德逊湾/福克斯盆地。核心研究问题是：（1）加拿大北极地区海洋DIC和DOC的分布和14 C年龄是什么？(2)加拿大北极水团的停留时间和通风年龄是多少？(3)这些地区持续存在的碳的主要来源是什么？DOC的生物分子和化学组成在多大程度上决定了其在北极沃茨中对异养细菌的生物有效性和长期持久性（即14 C年龄）？这些问题将在实地和实验室为基础的研究进行了4个硕士生，3个博士生和6-8个本科生，招募和培训使用旨在最大限度地提高公平，多样性和包容性的方法。我们的研究结果将促进我们对加拿大北极地区海洋碳循环动态的理解，并提高我们预测碳储量和通量的能力。这项工作也将有助于提高我们的能力，参数化和纳入DOC地球化学循环到未来的北极地球系统模型。该研究将利用与加拿大国内外世界知名研究人员的新的和现有的合作。这项研究将整合使用两个国家研究设施，安德烈E。拉隆德加速器质谱实验室和阿蒙森科学-进一步建立加拿大的形象，作为一个领导者在碳循环研究在一个快速的北极气候变化时期。我在开发和改进海洋14 C方法方面发挥了主导作用，这些方法帮助我们量化了海洋中有机碳循环的速率。我在化学海洋学，同位素地球化学和加速器质谱领域的跨学科背景使我有资格领导拟议的研究计划。