Award: OCE-1639865

This one-year EAGER grant allowed PI James Waples (University of Wisconsin-Milwaukee) to develop a method for measuring the naturally occurring radionuclides of bismuth-210 (210Bi; half-life: 5.01 days), lead-210 (210Pb; half-life: 22.3 years), and polonium-210 (210Po; half-life: 138 days) in aquatic systems. 210Bi is the daughter of 210Pb and the parent 210Po, and while 210Pb and 210Po have been routinely measured in aquatic systems for nearly half a century, measurements of 210Bi are rare and its behavior in lakes and oceans is poorly understood. Community interest in naturally occurring radionuclides stems from our ability to use them as tracers of rates of aquatic system processes including e.g., particle settling, which ultimately affects the rate of carbon dioxide removal from the atmosphere and the transport and fate of many terrestrial and anthropogenic materials (e.g., nutrients and toxins) in coastal environments. This new method for measuring 210Pb, 210Bi, and 210Po (Figure 1) is simple and rapid and shortens the time currently needed for measuring 210Pb and 210Po by nearly an order of magnitude. A timeseries analysis of dissolved and particle-bound activities of 210Pb, 210Bi, and 210Po in water samples from Lake Michigan suggests that 210Bi might successfully be used as a tracer of rapid particulate flux. This field dataset is the largest yet assembled for 210Bi activities in a natural aquatic system. Results from this project have been presented at the Association for the Sciences of Limnology and Oceanography 2019 Aquatic Sciences Meeting and a manuscript describing: (1) details of the methodology; (2) decay-corrected calculations for total, dissolved, and particle-bound fractions of each nuclide; and (3) all field measurements has been submitted for peer review. Last Modified: 10/24/2019 Submitted by: James T Waples