Chapter 3

Overview of Aquatic Ecosystems

    • Trophic level Structure
        • Organisms interrelate through their feeding mode
        • Each organism has a feeding or trophic level defined by where it is located on the food chain
        • Organisms on one level feed on organisms on the level below (figure 3.4)
    • Healthy Ecosystem
        • Food chains within interrelate and interconnect to form a food web (figure 3.2)
        • The more complex the food web, the stronger and healthier the ecosystem

    • Greater diversity of species
        • High diversity can mean less stress from pollutants and other destabilizing forces
        • Simplicity breeds instability in an environment
    • Contaminant Transfer
        • Contaminants can be soluble in fats and oils but not water.
        • These can be absorbed across membranes and stored in body fat reserves
        • Contaminants can be absorbed as into a shell
        • Contaminants can be acquired through ingestion 
        • Contaminants can be excreted to some degree
        •  Many synthetic chemicals cannot be broken down and are retained.
        • They can bio-accumulate in a body (figure 3.8)
    • Bio-magnification
        • Takes place as organisms in each trophic level feed on the level below
          and increase levels of concentration as they go (figure 3.9)
    • Environmental Fate
        • The end result of the source-pathway-sink concept of pollution
    • Impact of pollution on an environment can be studied through the
        • distribution and population of benthic macro invertebrates

Home | Training | Gallery | Members Area
© Copyright 2001 Lake Norman CoveKEEPERS   All rights reserved.
Hosted and maintained by McBryde Internet consulting
For technical questions e-mail