Postdoctoral Fellowship: OPP-PRF: Tracing Polar Sediments with Short-lived Radioisotopes in 75 years of Arctic and Antarctic Sediment Cores

Results provide the first systematic study of Arctic and Antarctic sediment accretion. Improving the tools we use to track changes in sedimentation will help coastal managers and decisionmakers understand how climate change is impacting polar coastlines and marine environments, and what local communities should expect in the future. Sediment cores will be subsampled and analyzed for the activities of 210Pb (half-life = 22.3 years) and 137Cs (half-life = 30.1 years) using alpha and gamma spectroscopy, respectively.

To provide context related to depositional environment, select subsamples will also be analyzed for sediment bulk density, grain size distribution, and organic content. A subset of samples with no measurable 210Pb or 137Cs activity will be analyzed for 14C to determine whether the lack of radioisotopes in a sample is because the core is simply too old, the true surface layer is missing, or because the shorter-lived radioisotopes did not accumulate.

By undertaking comprehensive spatial analysis of the distribution of 210Pb and 137Cs in Arctic and Antarctic sediments, this research will achieve three goals: first, measure the activity of short-lived radioisotopes in archived sediment cores, a service to the science community that is urgently needed before the isotopes decay beyond detection. Second, produce a comprehensive pole-wide atlas of sediment accretion rates.

And finally, conduct a temporal analysis of sedimentation rate changes over the last ~60 to 125 years along the Beaufort Sea coast of northern Alaska, an ecologically and economically important region experiencing environmental transformation due to climate warming.