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.

海洋碳循环在调节地球气候到几年的时间表的气候中起着重要作用。随着地球的其余部分，加拿大北极的变暖几乎是速度的两倍，因此，在未来几十年中，北极海将经历前所未有的变化。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。海洋碳采用多种形式，从大型特有碎屑到小的溶解有机碳（DOC）分子，再到溶解的无机碳盐（DIC；主要作为碳酸氢盐）。该提案旨在解决我们对加拿大北极海洋碳循环的理解中的基本知识差距。拟议的研究将对先进的稳定碳（13C）和放射性碳（14C）同位素测量，以及溶解的微生物生物标志物分析和核磁共振光谱，以量化碳源，转换和循环速度，三个加拿大北极区域内的碳源，转换和循环速度：Baffin Bay，Canadian Archipelago bay和Foxs basin/foxss/Hudson/Hudson/Hudson/canadian Archipelago和Hudson。核心研究问题是：（1）在加拿大北极地区，海洋DIC和DOC的分布和14C级是什么？ （2）加拿大北极水块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？ （4）DOC生物分子和化学组成最终在多大程度上决定了其对异养细菌的生物学可用性及其在北极水域中的长期持久性（即14c-age）？这些问题将在由4位MSC学生，3名博士生和6-8名本科生进行的现场和实验室研究中进行检查，该研究使用旨在最大化公平，多样性和包容性的方法进行了招募和培训。我们的结果将提高我们对加拿大北极地区海洋碳循环动力学的理解，并提高我们预测碳储备和通量的能力。这项工作还将有助于提高我们参数化并将DOC生物地球化学循环纳入未来的北极地球系统模型的能力。这项研究将利用与加拿大和国外的世界知名研究人员的新合作和现有的合作。这项研究将整合两种国家研究设施，即安德烈·埃E.Lalonde加速器质谱实验室和阿蒙森科学 - 在北极迅速的气候变化时期，进一步构建了加拿大作为碳循环研究的领导者的概况。我在开发和改善海洋14C方法方面发挥了领先作用，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具有独特的资格来领导拟议的研究计划。