The measurement and use of bismuth-210 as a tracer of particle flux in aquatic systems

自然产生的放射性核素提供了宝贵的“时钟”，用来研究地球和环境科学中的各种过程。半衰期较短的核素非常适合研究快速过程，但通常浓度很低，特别难以测量。探索性研究早期概念基金的目标是开发和演示一种新的分析方法，用于测量湖水、海水和相关颗粒中的铋-210(半衰期为5天)。由于铋往往与其母同位素铅-210(半衰期，22年)更多地与颗粒有关，铋-210/铅-210子体/母体对可能被用来研究与湖泊和沿海海洋中颗粒(沉积物)的形成和循环有关的极短时间尺度过程。对这些过程的了解对于理解这些多产和动态地区的碳循环和养分循环非常重要。这一探索性项目的具体目标是：1)展示一种改进的测量水生系统样品中铅-210/铋-210/钚-210三元组的方法；2)测量密歇根湖中的铅-210/铋-210/钚-210；以及3)探索使用铋-210/铅-210不平衡作为颗粒通量的替代指标的可行性。该项目将资助一名本科生研究人员度过暑假。

Naturally occurring radioactive nuclides provide invaluable "clocks" with which to investigate a wide range of processes in earth and environmental sciences. Nuclides with shorter half-lives are well suited to studying rapid processes, but are often present at very low concentrations and are particularly difficult to measure. The goal of this Early Concept Grant for Exploratory Research (EAGER) is to develop and demonstrate a new analytical method for measuring bismuth-210 (half life, 5 days) in lake water, seawater, and associated particles. Because bismuth tends to become associated with particles more than its parent isotope lead-210 (half life, 22 years), the bismuth-210/lead-210 daughter/parent pair can potentially be used to investigate very short time-scale processes associated with particle (sediment) formation and cycling in lakes and the coastal ocean. Knowledge about such processes is important to understanding carbon and nutrient cycling in these productive and dynamic areas. The specific goals of this exploratory project are to 1) demonstrate an improved method for measuring the lead-210/bismuth-210/polonium-210 trio in aquatic system samples; 2) measure lead-210/bismuth-210/polonium-210 in Lake Michigan; and 3) explore the feasibility of using bismuth-210/lead-210 disequilibrium as a proxy for particle flux. The project would support an undergraduate student researcher for the summer.