Quantifying Food Web Changes in Lake Huron
By Dr. Douglas Haffner, Canada Research Chair Great Lakes Environmental Health, Great Lakes Institute for Environmental Research, University of Windsor
Dr. Haffner will be available for questions and discussion immediately following the seminar until 3:30 in the seminar room (B2-350).
The collapse of the food web of Lake Huron emphasizes our need to be able to quantify the effects of multiple stressors in aquatic food webs. This seminar investigates the use of persistent organic pollutants, such as PCBS, as ecological tracers to estimate energy and nutrient flow in food webs. Research is based on the assumption that super hydrophobic congeners (log Kow > 6.5) are taken up by fish as food, and these chemicals cannot be eliminated within the life time of the organism. Thus the body burden reflects total amount of food consumed by a fish at a given age. It is demonstrated how these and other bioenergetics indicators can be used to compare multiple trophic level responses to food web collapse, and provide insight to the importance of nutrient recycling by upper trophic levels. The integration of toxico-kinetic models with bio-energetic models provides a promising future of investigating in situ food web dynamics and processes.
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