PARENT SESSION
PM8 - Mercury: Fate, Transport, & Bioaccumulation
Monday, 18 November 2002
8:00 AM to 6:30 PM
Exhibit Hall
(P280) Upstream or Downwind? The roles of biotransport and atmospheric deposition in Hg accumulation in inland Arctic susbsistence fisheries.
Allen-Gil, Susan*,1, Ford, Jesse2, Seigle, John2, 1 Ithaca College, Ithaca, NY, USA2 Oregon State University, Corvallis, OR, USA
ABSTRACT- This project examines the role of the two amphidromous fish species (least cisco and broad whitefish) in biotransport of pollutants in northern Alaska. At selected coastal plain subsistence lakes, we collected sediment, plankton, and several fish species. Trophic position of fish is being examined using N15/N14 ratios . The relative influence of the marine system to individual fish is being examined using ratios of C13/C12 in muscle as well as Sr/Ca ratios in otoliths. Site differences were found for N15/N14, C13/C12 in least cisco and broad whitefish, but only for C13/C12 in northern pike (a resident species). Hg was not correlated with either C13/C12 or N15/N14 in least cisco or broad whitefish, but significant correlations were observed between both isotopes (C13/C12 and N15/N14) and Hg in pike, with the stronger correlation being with C13/C12. Based on the C13/C12 values of all fish species collectively, four sites had stronger signals of marine influence (less terrestrially derived C) than the other sites. These sites did not have higher [Hg] in fish, suggesting that Hg is not biotransported by fish into these systems from the marine environment to a significant extent, and that atmospheric, local and/or geological sources are probably more important.
Key words: biotransport, Hg, stable isotopes