Pathways of material and contaminant transfer within Great Lake food webs
- Michigan State Univ., East Lansing, MI (United States)
- Univ. of Connecticut, Groton, CT (United States)
- Univ. of Maryland, Solomons, MD (United States). Chesapeake Biological Lab.
Pathways of material transfer to Lake Michigan and Lake Superior sculpins were delineated using {delta}{sup 15}N values that will also provide a basis to assess the bioaccumulation of organic contaminants in these organisms. The {delta}{sup 15}N values of sculpins increased with depth along a transact from shallow to deep stations. Individuals from shallow, intermediate and deep water stations had {delta}{sup 15}N values of 11.2% {+-} 0.3, 12.99% {+-} 0.5 and 13.7% {+-} 0.7, respectively. The {delta}{sup 15}N values of mysids and amphipods from the deep station were 8.7 and 11.0, respectively. Assuming a 3% shift in {delta}{sup 15}N with trophic level, these data suggest that mysids are the dominant prey item to shallow water sculpins whereas amphipods predominate the diet of deep water sculpins. These data are consistent with stomach content analysis and, therefore, imply that short and long term dietary assessments provide similar information for sculpins. The predominance of amphipods in the diet of deep water sculpins is significant given that amphipods are much less abundant than mysids at this station. The greater attenuation of light at deep station appears to facilitate the capture of small prey, such as amphipods, by sculpins. The discrepancy between interpretations of diet based on isotope analysis and those based on relative abundance of prey items serves to emphasize the importance of a careful assessment of pathways of material transfer in food webs and suggests that isotope analysis are an important first step in delineating mechanisms of contaminant transfer.
- OSTI ID:
- 49517
- Report Number(s):
- CONF-9410273--
- Country of Publication:
- United States
- Language:
- English
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