Date of this Version
The Prairie Naturalist 45: 100-105. December 2013
Bioaccumulation of mercury is well-documented in aquatic ecosystems and occurs as mercury is accumulated and passed up food chains (Kidd et al. 1995, Atwell et al. 1998, Downs et al. 1998). Trophic level correlations have been widely reported for mercury (Snodgrass et al. 2000) and other metals (Barron 1995). Generally, within a system, carnivores have the highest mercury loadings, omnivores intermediate and herbivores the lowest (Phillips et al. 1980). However, little research has focused on the differences in mercury bioaccumulation for a single species that ranges across multiple trophic levels (Burger et al. 2001).
Stable isotope analysis has expanded the understanding of pathways and mechanisms that promote bioaccumulation through food webs (Peterson and Fry 1987). For example, nitrogen enrichment at each trophic transfer can describe an individual’s trophic position and often is correlated to contaminant concentrations (Sunda and Huntsman 1998) and bioaccumulation rates (Atwell et al. 1998). Further, distinct carbon signatures can describe energy inputs to a system or an individual (e.g., benthic vs. littoral energy base; Hecky and Hesslein 1995) and can provide information on how different contaminants are introduced into a water.