Development and Application of Geochemical and Isotopic Tracers to Investigate Environmental Processes

地球化学和同位素示踪剂的开发和应用以研究环境过程

• 批准号: RGPIN-2015-05467
• 负责人: Francois, Roger
• 金额: $ 2.4万
• 依托单位: University of British Columbia
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=651064
• 关键词: Development; Application; Geochemical; Isotopic; Tracers

Human activities are increasingly altering climate and the environment and we must improve our predictive capabilities to decide on optimal societal responses to mitigate their negative impacts. Foremost among these concerns is the rise in atmospheric CO2, resulting in global warming and ocean acidification, and multiple feedbacks that can further affect the evolution of climate and marine ecosystem services. The ocean has played a key role in past changes in atmospheric CO2 and climate, and today it is a major sink for anthropogenic CO2. The main oceanic processes that affect atmospheric CO2 are circulation and the sinking flux of organic matter produced by marine ecosystems, which both control the sequestration of carbon to the deep sea and the chemistry of surface water in contact with the atmosphere. Predicting the trajectory of future environmental and climate changes thus requires a detailed documentation of the evolution of these processes in response to past climate changes and their quantification in the modern ocean. One approach towards achieving such predictive capability is to use the inherent integrative power of multiple geochemical tracers, which are either recorded in marine archives and provide information on changes in oceanic processes in relation to past climate variability, or which are imprinted in the water column and provides information on modern oceanic processes. A wide array of geochemical tracers is being developed to provide information on multiple oceanic processes in a multi-proxy, cross-checking context. The present proposal applies this general approach and builds on results obtained in the past five years. It combines sediment and water column study of (1) natural radioisotopes (230Th, 234Th, 231Pa) to constrain particle sinking flux in the ocean and deep water circulation, (2) neodymium isotopes which trace oceanic water masses and provide information on oceanic input of essential elements from partial dissolution of minerals brought to the sea from continents (a process recently coined as "Boundary Exchange"), and (3) chromium isotopes , which provide complementary information on boundary exchange, carbon sequestration, and the redox state of modern and past oceans.***In addition to addressing these broad environmental questions, I have started and will continue to address questions pertaining more directly to environmental monitoring. I am investigating the use silver and cadmium isotopes to establish the source and dispersion of these toxic metals in coastal waters, and my group has developed a novel flow-through dissolution module to measure the kinetics of dissolution of minerals (which is also relevant to the questions of boundary exchange mentioned above), to estimate the release of toxic metals from mine wastes, and to evaluate the potential of mine waste for carbon sequestration.**

人类活动正在日益改变气候和环境，我们必须提高我们的预测能力，以决定最佳的社会反应，以减轻其负面影响。在这些担忧中，最重要的是大气中二氧化碳的增加，导致全球变暖和海洋酸化，以及可能进一步影响气候和海洋生态系统服务演变的多重反馈。海洋在过去的大气二氧化碳和气候变化中发挥了关键作用，今天它是人为二氧化碳的主要汇。影响大气CO2的主要海洋过程是海洋生态系统产生的有机物的循环和下沉通量，它们既控制着碳在深海的固存，又控制着与大气接触的地表水的化学性质。因此，预测未来环境和气候变化的轨迹需要详细记录这些过程对过去气候变化的响应及其在现代海洋中的量化。实现这种预测能力的一种方法是利用多种地球化学示踪剂固有的综合能力，这些示踪剂要么记录在海洋档案中，提供与过去气候变率有关的海洋过程变化的信息，要么烙印在水柱中，提供关于现代海洋过程的信息。目前正在开发一系列广泛的地球化学示踪剂，以便在多代理、交叉核查的情况下提供有关多种海洋过程的信息。本建议适用这一一般办法，并以过去五年取得的成果为基础。它结合了沉积物和水柱的研究：(1)天然放射性同位素（230Th, 234, 231Pa），以限制海洋和深水循环中的粒子沉降通量；(2)钕同位素，追踪海洋水团，并提供有关从大陆带到海洋的矿物部分溶解的海洋输入的基本元素的信息（这一过程最近被称为“边界交换”）；它们提供了关于边界交换、碳固存以及现代和过去海洋氧化还原状态的补充信息。除了解决这些广泛的环境问题外，我已经开始并将继续解决与环境监测更直接有关的问题。我正在研究使用银和镉同位素来确定这些有毒金属在沿海水域的来源和扩散，我的小组已经开发了一种新的流动-通过溶解模块来测量矿物溶解的动力学（这也与上面提到的边界交换问题有关），以估计矿山废物中有毒金属的释放，并评估矿山废物的碳封存潜力