A test of the possible influence of seabird activity on the 210Pb flux in high Arctic ponds at Cape Vera, Devon Island, Nunavut: implications for radiochronology
A large seabird colony of northern fulmars (Fulmarus glacialis) at Cape Vera on Devon Island in the Canadian high Arctic has been shown to act as an effective biological pump, transporting large quantities of marine-derived nutrients and contaminants to the ponds beneath their nesting sites. Previous research has shown that seabirds also have the potential to elevate radionuclide concentrations in their immediate surroundings. Here, we assess the influence of the Cape Vera seabird colony on the 210Pb budgets of six affected ponds and one control site, and discuss potential implications with respect to 210Pb dating methodologies. In general, fluxes of 210Pb at Cape Vera were similar to, or less than, those measured at other Arctic locations not influenced by seabirds. Plots of unsupported 210Pb activity versus depth showed a number of non-monotonic features in all sediment cores, necessitating the use of the constant-rate-of-supply (CRS) model to derive age-depth profiles. We conclude that seabird activity has not dramatically increased the 210Pb flux to the ponds at Cape Vera. Overall, the low flux of excess 210Pb made accurate dating problematic for some of the study cores, necessitating the use of independent dating markers (e.g., 137Cs and PCB concentrations) to verify the reliability of the chronologies.
Keywords210Pb radiochronology Paleolimnology Arctic ponds Biovectors Northern fulmars Polychlorinated biphenyls Contaminants
This work was funded by Strategic and Discovery grants from the Natural Science and Engineering Research Council of Canada awarded to JMB, MSVD, and JPS, and a Northern Scientific Training Program (NSTP) grant to BEK. We thank the Polar Continental Shelf Project/Étude du Plateau Continental Polaire (PCSP/ÉPCP), NSTP and Environment Canada (CWS) for financial and logistical support in the field. The quality of this manuscript was greatly improved by two anonymous reviewers. This represents PCSP/ÉPCP contribution No. 03207.
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