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: 2017
• 资助国家: 加拿大
• 起止时间: 2017-01-01 至 2018-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=633869
• 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.

人类活动越来越多地改变气候和环境，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。这些问题中最重要的是大气二氧化碳的增加，导致全球变暖和海洋化，以及多种反馈，这些反馈可以进一步影响气候和海洋生态系统服务的发展。海洋在大气二氧化碳和气候的过去变化中发挥了关键作用，如今，它是人为二氧化碳的主要水槽。影响大气二氧化碳的主要海洋过程是循环和海洋生态系统产生的有机物的下沉通量，它们既控制着碳形成深海的形成，又控制与大气接触的地表水的化学。因此，预测未来环境和气候变化的轨迹需要详细的文献记录这些过程的演变，以响应过去的气候变化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使用多个地球化学示踪剂的固有综合能力，这些示踪剂要么记录在海洋档案中，并提供有关过去气候变化相关的海洋过程变化的信息，要么在水柱中印记，并提供有关现代海洋过程的信息。正在开发各种各样的地球化学示踪剂，以提供有关多种海洋过程的信息。本提案采用了这种一般方法，并基于在过去五年中获得的结果。它结合了（1）天然放射性病（230，234，231pa）的沉积物和水柱研究，以限制海洋中的粒子下沉的粒子下沉和深水循环，（2）新近同位素痕迹，这些neodrodmium neododmium同位素是海洋水质量的，这些同位素是从延续的海洋中汇出的基本元素的信息（三种延伸）（3月份）（3.最近）（3.最近的矿物）（3.最近的境外）（3.最近（3.同位素提供有关边界交换，碳固存以及现代和过去海洋的氧化还原状态的完整信息。