"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.

海洋自养生物的固碳作用是水泥工业和化石燃料燃烧释放到大气中的碳的一个重要汇（约26%）。无机碳（CO2）通过浮游生物的光合吸收被同化为生物物质。这种生物材料絮凝和下沉，并在海洋混合层中被分解或输出到海洋深层进行长期封存（“生物碳泵”）。了解有多少这种颗粒物质转移到深海，对于量化海洋在减轻人为二氧化碳大气排放，从而减轻气候变化方面的作用非常重要。这些颗粒输出通量可以量化使用一些方法，包括放射性化学示踪剂和沉积物捕集。在现有的放射化学技术中，234 Th的使用是最常用的。234 Th很容易附着在粒子上，加上它的半衰期很短（24.1天），使它成为一种理想的示踪剂，可以追踪在海柱中下沉的粒子。传统上，采用大体积（由于通常在海洋中发现的低颗粒234 Th活性）原位泵来收集颗粒，使得该方法非常劳动密集，并且在过滤期间还需要长时间的静态船舶。这导致海洋中这一变量的采样严重不足，导致报告的生物碳泵大小不一致。Argo浮标和滑翔机上使用的原位传感器对海洋物理学和化学产生了变革性影响，但类似的微粒传感器和采样器并不存在。该技术提案试图通过将原位颗粒通量仪器的概念引入TRL 4来解决这一数据缺口。这将通过开发原位过滤系统并将其与新型可部署β检测模块耦合来测量颗粒234 Th活性来实现。这将为进一步提高该装置的TRL和将创新技术原则应用于其他海洋变量（即溶解相放射性核素;其他放射性核素）的工作奠定基础。使用自动驾驶车辆以高空间和时间分辨率轻松采集公海通量的能力将使我们在不断变化的海洋中测量碳输出（脱氧，酸化）的能力发生重大变化，并帮助科学家评估大气二氧化碳浓度增加的长期影响。