HR: 0800h
AN: B51C-0600    [Abstracts]
TI: Mercury biomagnification in polar bears ( Ursus maritimus)
AU: * Horton, T W
EM: travis.horton@canterbury.ac.nz
AF: University of Canterbury, Private Bag 4800, Christchurch, 8140, New Zealand
AU: Blum, J D
AF: University of Michigan, Department of Geological Sciences, Ann Arbor, MI 48109-1005, United States
AU: Xie, Z
AF: University of Michigan, Department of Geological Sciences, Ann Arbor, MI 48109-1005, United States
AU: Hren, M
AF: Stanford University, Geological and Environmental Science Department, Stanford, CA 94305-2115, United States
AU: Chamberlain, C P
AF: Stanford University, Geological and Environmental Science Department, Stanford, CA 94305-2115, United States
AB: Mercury biomagnification occurs in a variety of ecosystems resulting in greater potential for toxicological effects in higher-level trophic feeders. However, Hg transport pathways through different foodweb channels are not well known, particularly in high-latitude systems affected by atmospheric Hg deposition associated with snow and ice. Stable carbon and nitrogen isotope ratios and Hg concentrations determined for 26 late 19th and early 20th century polar bear hair specimens collected from cataloged museum collections elucidate relationships between high latitude marine foodweb structure and Hg transport pathways. Nitrogen and carbon isotopic compositions suggest that polar bears derive nutrition from both open water (pelagic) and ice associated (sympagic) foodweb channels. Correlation between Hg concentrations and nitrogen isotope compositions indicate mercury biomagnification occurred in most of the polar bears investigated. Interpretation of stable isotope based foodweb structure in concert with Hg concentrations further suggests that Hg biomagnification occurred to a greater degree in polar bears participating in pelagic foodweb channels.
DE: 0439 Ecosystems, structure and dynamics (4815)
DE: 0460 Marine systems (4800)
DE: 0489 Trace element cycling (4875)
DE: 0491 Food webs and trophodynamics (4817)
DE: 1041 Stable isotope geochemistry (0454, 4870)
SC: Biogeosciences [B]
MN: 2007 Fall Meeting