Distribution and abundance of benthic algae (periphyton). In particular, my recent research is centered on 1) the effects of residential development on the littoral algae and invertebrates of Quebec lakes, 2) the distribution of filamentous algae and benthic cyanobacteria in the St. Lawrence River and implications of their proliferation on the chemistry and trophy of the river, 3) the response of diatom communities to metal pollution and their utilisation as early indicators of ecosystem recovery.