Marine & Environmental Sciences Faculty Proceedings, Presentations, Speeches, Lectures

Using Subsistence-Harvested Bowhead Whale Baleen as a Multi-Decadal Contaminant Recorder

Event Name/Location

World Marine Mammal Conference, Barcelona, Spain, December 9-12, 2019

Presentation Date

12-9-2019

Document Type

Poster

Description

Potentially harmful concentrations of heavy metals have been recorded in marine mammals as far north as the Arctic Beaufort Sea. Bowhead whales (Balaena mysticetus) annually migrate from their winter foraging grounds of the Bering Sea into the Chukchi Sea and eastward to the Beaufort Sea (summer). A single baleen plate from a bowhead whale grows continuously and can store more than 20 years of dietary and, subsequently, environmental data. Analysis of heavy metals in western Arctic bowhead whale baleen plates, via atomic absorption spectrophotometry, confirmed successful detection of twelve heavy metals (Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Se, V, Zn). Baleen plates obtained from subsistence-harvested bowhead whales between 1966 and 1999 were analyzed, providing first-ever heavy metal data from 1947-1999. Previous stable carbon and nitrogen isotope analyses from the same baleen of these whales ascertained the general locations and seasons (Beaufort Sea in summer/fall; Bering/Chukchi seas in winter/spring) along the western Arctic population’s migration path. Comparing heavy metal concentrations to the respective stable isotope values of the same sample allowed concentrations to be attributed to general season and region. There were significant differences among elements (X2(11)=341.44, p=<2.2e-16), with copper, vanadium, and zinc having the highest average concentrations (338 ppm, 835 ppm, 226 ppm, respectively), and cadmium, chromium, and manganese having the lowest (4 ppm, 2 ppm, 3 ppm, respectively). All metal concentrations fluctuated temporally, but did not increase nor decrease over time. Seasonally, nickel and zinc were highest in winter and spring (Bering and Chukchi seas), while mercury was generally highest in summer and fall (Beaufort Sea).

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