"Particle Radio-sensor": Development of in situ particulate radioactivity sensor

“粒子放射传感器”：原位粒子放射性传感器的开发

• 批准号: NE/R01230X/1
• 负责人: Matt Mowlem
• 金额: $ 17.42万
• 依托单位: NATIONAL OCEANOGRAPHY CENTRE
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2018
• 资助国家: 英国
• 起止时间: 2018 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FR01230X%2F1
• 关键词: Particle; Radio; sensor; Development; situ

Carbon fixation by marine autotrophs represents a significant (~26%) sink of the carbon released to the atmosphere from the cement industry and burning of fossil fuels. Inorganic carbon (CO2) is assimilated into biological material via photosynthetic uptake by plankton. This biological material flocculates and sinks, and is either remineralised within the ocean mixed layer or exported to deeper layers of the ocean for long term sequestration (the 'biological carbon pump'). Understanding how much of this particulate material is transferred to the deep ocean is important in quantifying the role the oceans will play in ameliorating anthropogenic atmospheric emissions of CO2, and hence climate change. These particulate export fluxes can be quantified using a number of approaches including radiochemical tracers and sediment trapping. Of the radiochemical techniques available, the use of 234Th is the most commonly applied. The 234Th readily adheres to particles, and combined with its short half-life (24.1 days) make it an ideal tracer of particles sinking through the ocean column. Traditionally, large volume (owing to the low particulate 234Th activities typically found in the oceans) in situ pumps are employed to collect particles making this method very labour intensive, and also requiring long periods of static ship during filtration periods. This leads to gross under-sampling in the oceans of this variable, leading to inconsistencies reported for the magnitude of the biological carbon pump. In situ sensors such as those used on Argo floats and gliders have been transformative for marine physics and chemistry, but analogous particulate sensors and samplers do not exist. This technology proposal seeks to address this data gap by taking the concept of an in situ particulate flux instrument to TRL 4. This will be achieved by developing an in situ filtration system and coupling this with a novel deployable beta detection module to measure particulate 234Th activity. This will provide the foundations for further work to raise the TRL of this device and to apply the innovative technology principles to other oceanic variables (i.e. dissolved phase radionuclides; other radionuclides). The ability to easily sample open ocean fluxes using autonomous vehicles at high spatial and temporal resolution would constitute a step-change in our ability to measure carbon export in a changing ocean (deoxygenation, acidification) and help scientists assess the long term effect of increasing atmospheric CO2 concentration.

海洋自动营养的碳固定量代表了从水泥行业释放到大气和化石燃料的大气中的碳的显着（约26％）。浮游生物通过光合作用吸收将无机碳（CO2）吸收到生物材料中。这种生物材料会絮凝和下沉，要么在海洋混合层中重新矿物质，要么被导出到海洋较深的层以进行长期隔离（“生物碳泵”）。了解这种颗粒物材料的多少被转移到深海中对于量化海洋将在改善二氧化碳的人为大气排放量以及因此气候变化中所起的作用很重要。这些颗粒物的导出通量可以使用多种方法进行量化，包括放射化学示踪剂和沉积物捕获。在可用的放射化学技术中，最常用的234使用是使用。第234条很容易粘附在颗粒上，并结合其短的半衰期（24.1天）使其成为通过海洋柱下沉的颗粒的理想示踪剂。传统上，用原位泵收集颗粒，从而使这种方法非常密集，并且在过滤期间需要长时间的静态船。这导致该变量的海洋中的沉积不足，从而导致报道的生物碳泵的幅度不一致。原位传感器（例如在Argo浮子上使用的传感器）对海洋物理和化学的转化是有变化的，但是不存在类似的颗粒传感器和采样器。该技术建议旨在通过将原位颗粒物仪器的概念提取到TRL 4来解决这一数据差距。这将通过开发原位过滤系统来实现，并将其与新颖的可部署beta检测模块耦合以测量颗粒234活性。这将为进一步的工作提供基础，以提高该设备的TRL并将创新技术原理应用于其他海洋变量（即溶解的相核素；其他放射性核素）。在高空间和时间分辨率上使用自动驾驶汽车轻松采样开放海洋通量的能力将构成我们在不断变化的海洋中测量碳出口（脱氧，酸化）的能力，并帮助科学家评估大气CO2浓度增加的长期效果。