13C vs PCBs separate food web members into three distinct groupings comprised of invertebrates, primary forage fish, and predatory fish. Stable isotope values of the primary organic sources indicate that the atmosphere, and not the sediment, is the most likely source of PCBs to the food web of Lake Michigan. Additionally, we suggest that seston may be important in delivering PCBs to pelagic food web members and species that receive a majority of their nutrition through pelagic sources. In contrast, settling particles are implicated in delivering PCBs to benthic organisms and Mysis relicta. " />
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SEASONAL DYNAMICS OF PCB ACCUMULATION IN A GREAT LAKES FOOD WEB. (R825151)
Citation:
Stapleton, H. M., C. Masterson, J. Scubinna, T. Coon, D. Hall, P. Ostrom, N. E. Ostrom, AND J. E. Baker. SEASONAL DYNAMICS OF PCB ACCUMULATION IN A GREAT LAKES FOOD WEB. (R825151). ENVIRONMENTAL SCIENCE & TECHNOLOGY. American Chemical Society, Washington, DC.
Description:
Seston, sediment, settling organic matter, and food web members were
collected from Grand Traverse Bay, Lake Michigan, between April 1997 and
September 1998 to examine PCB and toxaphene biomagnification. Stable isotopes of
nitrogen and carbon were analyzed in samples and used to establish trophic
structure of the food web and to determine the importance of atmospheric versus
sedimentary sources in delivering PCBs to the food web. Nitrogen isotopes were
confounded by multiple variables in this system, particularly seasonal
variation, and did not display a simple pattern of enrichment among trophic
levels. However, src="/ncer/pubs/images/delta.gif">13C displayed little seasonal
variation and was positively correlated with PCB concentrations among food web
members (r2 = 0.69). Plots of src="/ncer/pubs/images/delta.gif">13C vs PCBs separate food web
members into three distinct groupings comprised of invertebrates, primary forage
fish, and predatory fish. Stable isotope values of the primary organic sources
indicate that the atmosphere, and not the sediment, is the most likely source of
PCBs to the food web of Lake Michigan. Additionally, we suggest that seston may
be important in delivering PCBs to pelagic food web members and species that
receive a majority of their nutrition through pelagic sources. In contrast,
settling particles are implicated in delivering PCBs to benthic organisms and
Mysis relicta.