Date of Award


Publication Type

Master Thesis

Degree Name



Biological Sciences

First Advisor

Doust, J. L.


Biology, Ecology.




Leaf-to-root surface area ratios in Vallisneria americana provide a simple and inexpensive, relative measure of sub-lethal effects of organochlorine contamination. The present study was conducted to determine whether this index of surface area could be used as an effective biomonitor of overall site quality in stressed aquatic ecosystems. The leaf-to-root surface area ratio was determined for samples of V. americana collected from 225 microsites within 12 Areas of Concern (environmentally contaminated areas designated by the International Joint Commission) throughout the Laurentian Great Lakes of Ontario. Observations support the hypothesis that V. americana accumulates contaminants primarily from the sediments. Both the leaf-to-root fresh mass ratio, and total fresh mass of V. americana plants showed similar results and could be used as approximate substitutes for the leaf-to-root surface area ratio. Mapping contours of leaf-to-root surface area ratios appeared to correspond with suspected contours of contamination, enabling the identification of point source impact zones. It is concluded that the regression model developed here provides a simple, inexpensive means for monitoring overall site quality throughout the Great Lakes. Measures of plant structure in V. americana were also investigated for use in sediment toxicity testing. (Abstract shortened by UMI.)Dept. of Biological Sciences. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis1998 .P68. Source: Masters Abstracts International, Volume: 39-02, page: 0444. Adviser: Lesley Lovett-Doust. Thesis (M.Sc.)--University of Windsor (Canada), 1998.