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Updated: Apr 1, 2026

Chemotactic Response of Marine Micro-Organisms to Micro-Scale Nutrient Layers
Published on: May 28, 2007
PCB Food Web Dynamics Quantify Nutrient and Energy Flow in Aquatic Ecosystems.
Anne M McLeod1, Gordon Paterson2, Ken G Drouillard1
1Great Lakes Institute for Environmental Research, University of Windsor , Windsor, Ontario, Canada N9B3P4.
Polychlorinated biphenyl (PCB) congeners can track nutrient and energy flow in aquatic ecosystems. Older lake trout recycle significant nitrogen, phosphorus, and energy, influencing lake nutrient levels.
Area of Science:
- Aquatic ecology
- Ecosystem dynamics
- Biogeochemical cycling
Background:
- Quantifying nutrient and energy flow in complex aquatic ecosystems is challenging.
- Understanding food web responses to stressors requires accurate flow measurements.
- Polychlorinated biphenyl (PCB) congeners offer a novel approach as ecological tracers.
Purpose of the Study:
- To demonstrate how PCB congener bioaccumulation dynamics can quantify in situ energy and nutrient flow.
- To investigate nitrogen (N), phosphorus (P), and caloric turnover rates in Lake Huron lake trout.
- To reveal how fish growth rate and life history regulate these processes.
Main Methods:
- Utilized PCB congener bioaccumulation dynamics as a tracer for nutrient and energy flow.
- Quantified N, P, and caloric turnover rates in lake trout populations.
- Analyzed the relationship between fish growth rate, life history, and nutrient/energy cycling.
Main Results:
- Slow-growing, older lake trout (>5 yr) recycled substantial amounts of N (482 Tonnes·yr(-1)), P (45 Tonnes·yr(-1)), and energy (22 TJ yr(-1)).
- Young, growing fish exhibited minimal nutrient recycling.
- Fish-driven nutrient recycling plays a significant role in regulating nutrient states of oligotrophic lakes.
Conclusions:
- PCB congener dynamics provide direct measurements of energy and nutrient flow in aquatic food webs.
- Life history and growth rate significantly influence nutrient and energy recycling by fish.
- Fish play a critical role in the biogeochemical cycling of nutrients in oligotrophic lake ecosystems.
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